Improving acetic acid production of acetobacter pasteurianus AC2005 in hawthorn vinegar fermentation by using beer for seed culture

International Journal of Food Science and Technology 2010, 45, 2209–2218 Review article Influence of soaking on the nutritional quality of common beans (Phaseolus vulgaris L.) cooked with or without the soaking water: a review Ana Carolina Fernandes, Waleska Nishida & Rossana P da Costa Proenc¸a* Graduate Program in Nutrition, Nutrition in Foodservices Research Group (NUPPRE), Department of Nutrition, Federal University of Santa Catarina (UFSC), Campus Trindade, CEP 88.040-970, Floriano´polis, SC, Brazil (Received 12 April 2010; Accepted in revised form 26 July 2010) Summary Bean soaking seems to be unanimously recommended by scientists; however, there is no consensus regarding the need to discard the soaking water before cooking Thus, the present study proposes to review the influence of maceration on the nutritional quality of common beans (Phaseolus vulgaris L.) cooked with or without the soaking water, in an attempt to achieve agreement among scientists The article search was done in a systematic way and eleven studies were found Of these, three compared the use or not of the soaking water for cooking, seven of them discarded the soaking water and one used the soaking water This review discusses each nutrient and antinutrient regarding the effects of soaking and compares them with other studies done with legumes The results were not unanimous but there was a greater advantage to discarding the soaking water before cooking Keywords Antinutrients, bioavailability, cooking, dry beans, food quality, nutritional aspects, processing effects Introduction The common bean (Phaseolus vulgaris L.) is consumed worldwide, especially in Latin America and Africa (FAO, 2009) Because of its cultural and nutritional importance, the Brazilian food pyramid shows beans in a group of their own (Philippi et al., 1999) and the Food Guide for the Brazilian Population recommends the consumption of at least one portion of beans per day (Vasconcellos et al., 2006) However, beans contain compounds that can negatively affect their nutritional value, such as trypsin inhibitors, lectins, phytates, polyphenols (especially tannins in beans) and oligosaccharides (raffinose and stachyose) Some of these are thermolabile, disappearing after proper cooking, such as trypsin inhibitors and lectins Others are thermostable, but their concentrations are reduced by dissolution in water (Haro, 1983; Silva & Silva, 1999, 2000) Soaking the beans in water and discarding the water may eliminate a percentage of these compounds Some studies (Oliveira et al., 2001a,b; Ramı´ rez-Ca´rdenas et al., 2008) found a greater reduction in the content of tannins, phytates and oligosaccharides in beans that were soaked and cooked without the soaking water *Correspondent: E-mail: rossana@mbox1.ufsc.br However, Ramı´ rez-Ca´rdenas et al (2008) pointed out some studies that state that low concentrations of phytates and phenolic compounds can be protective against cancer and cardiovascular diseases Meanwhile, oligosaccharide fermentation may have positive results such as production of short-chain fatty acids and decrease in intestinal pH (Muzquiz, 2008; Campos-Vega et al., 2009) The positive or negative effects of these compounds seem to be more closely associated with their concentration in the beans, which varies according to type of bean, as well as their interaction with other components of the diet (Muzquiz, 2008; Ramı´ rez-Ca´rdenas et al., 2008) Bean soaking before cooking seems to be unanimously recommended by scientists; however, there is no consensus regarding the discarding of the soaking water Although many authors recommend the soaking water to be discarded to eliminate antinutritional factors, others seek to prove the beneficial effects of these factors, which have been associated with the prevention of diseases In this sense, it would be advantageous not to discard the soaking water Yet, the published studies present contradicting and inconclusive results, which, according to Muzquiz (2008), can be attributed to the use of different methodologies and parameters Therefore, a consensus regarding the fate of the soaking water is yet to be achieved doi:10.1111/j.1365-2621.2010.02395.x Ó 2010 The Authors International Journal of Food Science and Technology Ó 2010 Institute of Food Science and Technology 2209 2210 Soaking and nutritional quality of beans A C Fernandes et al The objective of the present study is to perform a systematic review of the influence of soaking on the nutritional quality of common beans (P vulgaris L.) cooked with or without the soaking water, to assess and compare the preparation methods and results and search for concordant recommendations among the studies Method A systematic search of articles that discuss the influence of soaking on the nutritional quality of common beans (P vulgaris L.) cooked with or without the soaking water, published between January 2004 and March 2009 was done The following databases were searched: Scielo (Scientific Electronic Library Online), Lilacs (Latin American and Caribbean Centre on Health Sciences Information) and Scopus – which includes 100% of the publications of the Medline (National Library of Medicine) database The keywords used for the search are listed in Table S1 The search was done separately for each language, using the keywords of the first line in combination with the keywords of the lower lines A total of twenty-two articles were found in Scielo, nine in Lilacs and 392 in Scopus Nineteen repeated texts were removed, totalling 404 studies Based on the systematic search model, inclusion and exclusion criteria were established to meet the objectives of the research The inclusion criteria of the articles were (i) original articles; (ii) articles in Portuguese, English or Spanish; (iii) studies with the common bean (P vulgaris L.); (iv) studies that analysed the effects of soaking the beans on its composition, digestibility or bioavailability in vitro or in vivo The exclusion criteria were (i) review articles; (ii) articles in languages other than the ones mentioned earlier; (iii) studies with coffee (called coffee beans in English); (iv) studies with only other types of legumes or with beans of different species; (v) studies that analysed the effect of soaking on the properties of the seeds, the bean plant or bean characteristics other than the nutritional and sensorial characteristics; (vi) studies that analysed the effects of soaking beans for preparations other than the traditional preparations (such as bean sweets, flours for supplements, animal feeds); (vii) studies that only compared bean varieties or cultivars, or compared different legumes, and did not compare different processing methods; (viii) studies that only covered the influence of different processing methods on the quality of the bean; (ix) articles that were not complete, even when they were ordered from the authors After the abstracts of all the articles were read, those that did not meet the inclusion criteria were excluded Only eleven studies were specifically about the influence of soaking on the nutritional quality of common beans (P vulgaris L.) cooked with or without the soaking water International Journal of Food Science and Technology 2010 The studies were analysed according to their year of publication, country of origin, objectives, variables, preparation methods and analyses, results and conclusions and ⁄ or recommendations of the authors Characteristics of the analysed articles The characteristics verified in the selected articles are described in Table S2 Most of these studies (27.3%) were done in Brazil (Oliveira et al., 2008; Ramı´ rezCa´rdenas et al., 2008; Toledo & Canniatti-Brazaca, 2008), followed by the United States of America (18.2%) (Luthria & Pastor-Corrales, 2006; Xu & Chang, 2008); then came Mexico (Carmona-Garcı´ a et al., 2007); Spain (Pujola` et al., 2007); Turkey (Nergiz & Goăkgoăz, 2007); Ethiopia (Shimelis & Rakshit, 2007); Sudan (Elmaki et al., 2007); and Pakistan (Rehman & Shah, 2004), each with 9.1% Regarding the objectives and variables, three studies (Oliveira et al., 2008; Ramı´ rez-Ca´rdenas et al., 2008; Toledo & Canniatti-Brazaca, 2008) assessed the effects of cooking the beans with or without the soaking water The other studies analysed the effects of different bean processing methods (raw, soaked, soaked and cooked, cooked without soaking), but did not discuss the use of the soaking water for cooking Of these eight studies, only one (Nergiz & Goăkgoăz, 2007) used the soaking water to cook the beans, while the other seven studies (Rehman & Shah, 2004; Luthria & Pastor-Corrales, 2006; Carmona-Garcı´ a et al., 2007; Elmaki et al., 2007; Pujola` et al., 2007; Shimelis & Rakshit, 2007; Xu & Chang, 2008) discarded the soaking water All articles analysed more than one variable Thus, the studies also assessed the effects of different cooking methods (vapour, boiling, pressure cooking, microwave (Toledo & Canniatti-Brazaca, 2008; Xu & Chang, 2008; Shimelis & Rakshit, 2007; Nergiz & Goăkgoăz, 2007; Rehman & Shah, 2004); of dierent soaking solutions other than pure water – sodium chloride (NaCl), sodium bicarbonate (NaHCO3) and mixed (NaCl + NaHCO3) (Rehman & Shah, 2004; Carmona-Garcı´ a et al., 2007; Shimelis & Rakshit, 2007); of different types of beans, different varieties, colours and cultivars (Luthria & Pastor-Corrales, 2006; Elmaki et al., 2007; Pujola` et al., 2007; Oliveira et al., 2008; Ramı´ rez-Ca´rdenas et al., 2008); of different soaking times (Elmaki et al., 2007; Xu & Chang, 2008) and of germinating the beans in the prepreparation phase (Shimelis & Rakshit, 2007) All articles also had more than one outcome variable The outcomes investigated most often were changes in phytate content (Elmaki et al., 2007; Nergiz & Goăkgoăz, 2007; Shimelis & Rakshit, 2007; Ram rez-Cardenas et al., 2008; Toledo & Canniatti-Brazaca, 2008), followed by tannins content (Nergiz & Goăkgoăz, 2007; Shimelis & Rakshit, 2007; Ram rez-Cardenas et al., 2008; Toledo & Canniatti-Brazaca, 2008), phenol content (total, polyphe- Ó 2010 The Authors International Journal of Food Science and Technology Ó 2010 Institute of Food Science and Technology Soaking and nutritional quality of beans A C Fernandes et al nols – which also include tannins and phenolic acids) (Luthria & Pastor-Corrales, 2006; Elmaki et al., 2007; Nergiz & Goăkgoăz, 2007; Xu & Chang, 2008) and mineral content (Elmaki et al., 2007; Pujola` et al., 2007; Oliveira et al., 2008; Ramı´ rez-Ca´rdenas et al., 2008); and in vitro protein digestibility (Nergiz & Goăkgoăz, 2007; Shimelis & Rakshit, 2007; Toledo & Canniatti-Brazaca, 2008) Other changes were also verified such as centesimal composition (Ramı´ rez-Ca´rdenas et al., 2008; Toledo & Canniatti-Brazaca, 2008); starch (total, available starch and resistant starch, amylose) (Carmona-Garcı´ a et al., 2007; Pujola` et al., 2007); fibres (Rehman & Shah, 2004; Ramı´ rez-Ca´rdenas et al., 2008); trypsin-inhibiting activity (Nergiz & Goăkgoăz, 2007; Shimelis & Rakshit, 2007); oligosaccharides (Shimelis & Rakshit, 2007); in addition to the capacity to extract minerals with HCl (Elmaki et al., 2007), among others The outcome variables associated with the nutrients and antinutrients are shown separately in Tables and 2, which also show the effects of different bean preparation methods on these variables Phytates and phytic acid The authors of all studies that assessed phytates stated that a reduction of these compounds is desirable The greatest reduction of phytates and phytic acid was achieved by soaking and cooking without the soaking water (Elmaki et al., 2007; Nergiz & Goăkgoăz, 2007; Ram rez-Cardenas et al., 2008; Toledo & CanniattiBrazaca, 2008) Toledo & Canniatti-Brazaca (2008) stated that phytate reduction was equal in samples with and without soaking, however, as shown in a table of their study, the phytate content varied according to cooking method On average, the greatest phytate content was found in beans that were cooked with the soaking water, followed by beans cooked without soaking and finally beans cooked without the soaking water Among soaked beans and for all cooking methods, beans cooked without the soaking water always had statistically lower phytate content than those cooked with the soaking water Similar results were found by Oliveira et al (2001b) in an older study with common beans, and by Boateng et al (2007), who studied the phytate content in another species of bean However, phytic acid reduction may not be needed for the utilisation of some nutrients A study done by Oliveira et al (2003) showed that phytic acid in concentrations as high as eight times of that found in raw common bean did not compromise the utilisation of casein by rats during a 10-day period Studies found that soaking and cooking had different effects on different legumes For example, Aranda et al (2004) concluded that high consumption of phytate from beans (Vicia faba L.) had no negative effects on the digestion of calcium (Ca) and magnesium (Mg) by rats However, through another mechanism, soaking and cooking increased the metabolic utilisation of Ca and Mg Meanwhile, Chopra & Sankhala (2004) found a significant association between soaking and reduced phytate contents, concomitant with increased iron bioavailability in horse gram (Dolichos biflorus) and moth bean (Phaseolus aconitifolius) The reduction of phytates and phytic acid (phytate salt) may not be necessary to improve the utilisation of all nutrients However, their presence may impair the utilisation of some micronutrients, thus their reduction is desirable In this sense, soaking, especially if the soaking water is discarded, can be recommended, as it proved to be an effective way to reduce phytates and phytic acid Total phenolic compounds In all the studies that assessed total phenolic compounds (Luthria & Pastor-Corrales, 2006; Elmaki et al., 2007; Nergiz & Goăkgoăz, 2007; Toledo & Canniatti-Brazaca, 2008; Xu & Chang, 2008), the loss of these compounds was greater in soaked beans cooked without the soaking water and proportional to the length of soaking A similar reduction was obtained for velvet beans (Mucuna pruriens) by Vadivel & Pugalenthi (2008, 2009), by soaking and discarding the water not absorbed by the beans, followed by autoclaving However, in the study by Luthria & Pastor-Corrales (2006), only 2% of the total phenolic compounds are lost in the soaking water, while 83% remain in the beans and 15% are probably lost during cooking The effect of soaking on the total amount of phenolic compounds was also discussed by Anton et al (2008) and Boateng et al (2007) In the first study, there were no significant changes in the total content of phenolic compounds in soaked but uncooked navy and pinto beans In the study by Boateng et al (2007), there was a significant reduction only in the total content of phenolic compounds of pinto beans The same was not observed for kidney beans after soaking and discarding the soaking water, without cook There is no consensus regarding the reduction of total phenolic compounds in beans when the inherent reduction of their antioxidant activity is assessed Ranilla et al (2009) found a relationship between the reduction of phenolic compounds and reduced antioxidant activity in soaked beans; however, the greatest loss was found in samples where the cooking water was discarded, which may indicate that great loss is because of cooking and may be avoided by consuming the beans with the cooking water Xu & Chang (2009) also found a relationship between the content of total phenolic compounds and antioxidant activity of beans However, there was no association between total phenolic acids and antioxidant activity in black beans, only in pinto beans The authors concluded that the greatest loss of phenolic compounds Ó 2010 The Authors International Journal of Food Science and Technology Ó 2010 Institute of Food Science and Technology International Journal of Food Science and Technology 2010 2211 Preparation methods International Journal of Food Science and Technology 2010 CWS Amylopectin, total and resistant starch: RAW Amylose: MC Total, available and resistant starch: COS Lipids Cellulose, lignin and hemicellulose: NaHCO3, CC & MC Total: CWS Soluble: COS Insoluble: CWS CWS Total: NS = CWS NS = COS = CWS Soluble: CWS Insoluble: NS = COS Fibres CL & COS Fe & Zn: NS Ca & Cu: CWS CWS = COS Minerals >extracta-bility >CL & COS Mineral extractability NS, not soaked; CWS, cooked with soaking water; COS, cooked without the soaking water; H2O, water; NaHCO3, sodium bicarbonate solution; CC, cooking in common pot or Mattson cooker; PC, cooking in pressure cooker or autoclave; MC, microwave cooking COS CWS NS Protein digestibility Carbohydrates CWS = COS NS = CWS Ashes Protein Toledo & NS CWS Canniatti-Brazaca, 2008 CWS COS Oliveira et al., 2008 RAW CWS COS CWS Ramı´rez-Ca´rdenas Raw et al., 2008 NS CWS COS Nergiz & Goăkgoăz, 2007 NS CWS Carmona-Garca COS et al., 2007 NS Elmaki et al., 2007 RAW COS Cooking length (CL) Pujola` et al., 2007 RAW MC COS Rehman & Shah, 2004 COS(H2O ⁄ NaHCO3) Cooking (CC, PC, MC) Study Table Selected studies, preparation methods and results regarding nutrients, indicating the methods that resulted in the greatest contents 2212 Soaking and nutritional quality of beans A C Fernandes et al International Journal of Food Science and Technology Ó 2010 Institute of Food Science and Technology Ó 2010 The Authors Soaking and nutritional quality of beans A C Fernandes et al Table Selected studies, preparation methods and results regarding the antinutrients, indicating the methods that resulted in the greatest reductions Study Toledo & Canniatti-Brazaca, 2008 Xu & Chang, 2008 Ramrez-Cardenas et al., 2008 Nergiz & Goăkgoăz, 2007 Shimelis & Rakshit, 2007 Pujola` et al., 2007 Elmaki et al., 2007 Luthria & Pastor-Corrales, 2006 Preparation Methods NS CWS COS COS Soaking length (SL) RAW NS CWS COS NS CWS COS (H2O; NaHCO3) Germination (G) Cooking (CC, PC) RAW S COS COS Soaking length (SL) RAW COS Phytates Tannins For author: Soaked = NS table: COS NS COS > CWS Oligosaccharides Total phenolic compounds Phytic acid Solids COS Longer SL COS COS Greatest content: NS CWS CWS CWS All fl G > NaHCO3 > H2O PC > CC S COS Longer SL 2% in the soaking water COS Longer SL NS, not soaked; CWS, cooked with soaking water; COS, cooked without the soaking water; H2O, water; NaHCO3, sodium bicarbonate solution; CC, cooking in common pot or Mattson cooker; PC, cooking in pressure cooker or autoclave; S, only soaked and consequently, of the antioxidant activity of the studied beans, is because of heat They also conclude that these changes depend upon the type of beans and processing conditions and that different phenolic contents might contribute to different degrees to the overall antioxidant activity The protective effect of beans against certain chronic diseases has been associated with the presence of phenolic compounds (Boateng et al., 2007; Xu et al., 2007) However, high levels may become undesirable when they impair digestion and protein absorption, inhibiting the activity of digestive enzymes such as a-amylase and trypsin (Vadivel & Pugalenthi, 2008) In this context, associating a partial reduction of total phenolic compounds with better absorption of bean proteins, soaking and discarding the water not absorbed by the beans before cooking, seems to be more appropriate Tannins Tannins are the most studied phenolic compounds of beans Usually the studies assess total phenolic compounds or tannins Among the selected articles, the reduction of tannins was considered desirable by all authors that analysed their content In one of the studies (Ramı´ rez-Ca´rdenas et al., 2008), there was a greater tannin reduction in beans that were soaked and cooked without the soaking water While comparing soaked beans cooked with the soaking water vs unsoaked beans, Nergiz & Goăkgoăz (2007) found lower tannin content in soaked beans On the other hand, Toledo & Canniatti-Brazaca (2008) found the lower tannin contents in all unsoaked samples and all cooking methods The authors justify that the greater loss is because of a longer cooking period, required when the beans are not previously soaked However, when the soaked beans are compared, the same study shows lower values for soaked beans cooked without the soaking water In the study by Oliveira et al (2001b), for whom tannin reduction was desirable, a greater reduction in tannin content was also obtained by discarding the soaking water In other studies with rojo bean (Mosha & Vicent, 2004), horse gram and moth bean (Chopra & Sankhala, 2004), soaking reduced the tannin levels significantly However, such compounds did not affect the bioavailability of zinc and iron in the study done by Hemalatha et al (2007) Tannins are also considered bioactive compounds because of their antioxidant capacity (Xu et al., 2007; Xu & Chang, 2009); however, they may have beneficial or adverse nutritional effects (Xu et al., 2007) In this sense, even though tannins not always interfere with the utilisation of nutrients, their reduction was considered desirable by all authors as they are Ó 2010 The Authors International Journal of Food Science and Technology Ó 2010 Institute of Food Science and Technology International Journal of Food Science and Technology 2010 2213 2214 Soaking and nutritional quality of beans A C Fernandes et al primarily an antinutritional factor Soaking and discarding the soaking water was the most effective way to reduce tannins Thus, this procedure can be recommended in the preparation of beans, also because soaking does not completely eliminate tannins from beans, thus the antioxidant activity attributed to this compound is partially preserved Thus, part of the antioxidant potential attributed to this compound can be preserved Oligosaccharides Only one of the selected studies assessed the oligosaccharide content of beans and how it changed with different preparation methods Shimelis & Rakshit (2007) studied the reduction of raffinose, stachyose and a-galactosides in two bean varieties (kidney bean) after soaking in water or a solution of sodium bicarbonate (NaHCO3) and cooking without the soaking water in a pot or autoclave The authors consider that reducing these oligosaccharides is desirable as they cause flatulence According to Shimelis & Rakshit (2007), both soaking solutions reduced the raffinose, stachyose and a-galactoside contents in both bean varieties The germination process, also investigated by the study, was the most effective method to reduce these compounds However, soaking also reduced their levels significantly, especially when a NaHCO3 solution was used Both soaking and cooking independently reduced the levels of all oligosaccharides Consequently, when the two processes were associated, there was a greater reduction of these sugars, which was even more effective when the beans were cooked in an autoclave (Shimelis & Rakshit, 2007) According to Granito et al (2007) in their study with Phaseolus lunatus beans, ⁄ of the raffinose content and ⁄ of the stachyose content are lost in the soaking water and the rest remained in the cooking water In another two studies that aimed to reduce stachyose and raffinose in bean-based processed products, soaking and cooking were effective for some bean varieties (Matella et al., 2005) or for some types of oligosaccharides (Siddiq et al., 2006) Matella et al (2005) found that soaking followed by discarding the soaking water reduced the oligosaccharide content of Michigan black beans and but did not affect the oligosaccharide contents of red and navy beans The analysis was done only in raw beans On the other hand, Siddiq et al (2006) found a significant reduction in the raffinose and stachyose contents of red kidney beans after soaking and discarding the soaking water Cooking further reduced the raffinose content but did not affect the stachyose content Although there are differences in the effectiveness of bean processing to reduce oligosaccharides, which depend on the specific oligosaccharide or bean variety, International Journal of Food Science and Technology 2010 soaking with subsequent discarding of the soaking water before cooking seems to reduce these compounds, something considered desirable in the reviewed studies Proteins and protein digestibility Protein content depended on preparation method and varied from study to study Toledo & Canniatti-Brazaca (2008) did not observe differences in the protein content of soaked beans cooked with or without the soaking water Meanwhile, Ramı´ rez-Ca´rdenas et al (2008) found greater absolute protein contents in beans cooked with the soaking water; this difference was not confirmed statistically Pujola` et al (2007) found a greater protein content in soaked beans cooked without the soaking water than in raw beans or uncooked soaked beans Other studies with legumes investigated if different preparation methods, such as soaking, extrusion and especially thermal treatments, led to protein loss (Osman, 2007; Teguia & Fon Fru, 2007; Huma et al., 2008) Rehman & Shah (2005) found that the protein content of lentils, chick peas, red kidney beans, white kidney beans and black grams (Vigna mungo) may not be affected by soaking, discarding the soaking water and cooking Toledo & Canniatti-Brazaca (2008) found that protein digestibility was lowest in beans cooked without the soaking water, but there was no difference between unsoaked cooked beans and beans cooked with the soaking water On the other hand, Nergiz & Goăkgoăz (2007) found that protein digestibility was greater in beans cooked with the soaking water than in unsoaked, cooked beans, but they did not investigate beans cooked without the soaking water A common observation is that bean processing reduces protein content but increases protein digestibility While studying chick peas, lentils and different types of beans, Martı´ n-Cabrejas et al (2009) and Rehman & Shah (2005) found that protein digestibility increased after soaking and cooking without the soaking water Soaking and cooking may reduce the contents of some antinutrients as, according to Shimelis & Rakshit (2005), tannins, trypsin inhibitors and some oligosaccharides correlate with lower protein digestibility in the haricot bean (P vulgaris L.) Although antinutritional factors are associated with lower protein digestibility, studies not agree on whether the soaking water should be discarded Preparation method does not seem to change protein content and digestibility Ashes, loss of solids, minerals and bioavailability Beans cooked with the soaking water had the highest ash contents (Ramı´ rez-Ca´rdenas et al., 2008; Toledo & Canniatti-Brazaca, 2008); however, soaking caused a Ó 2010 The Authors International Journal of Food Science and Technology Ó 2010 Institute of Food Science and Technology Soaking and nutritional quality of beans A C Fernandes et al greater loss of total solids, regardless of cooking with or without the soaking water (Pujola` et al., 2007) The lower ash content of soaked beans may be because of not only mineral lixiviation but also antinutritional factors Shimelis & Rakshit (2005) found a positive correlation between ash content and zinc and phytic acid contents in haricot beans (P vulgaris L.) Thus, a reduction of the ash content may be desirable Cooking also seems to reduce ash content (Osman, 2007) Mineral content varied from study to study Oliveira et al (2008) found that the mineral content of beans cooked with or without the soaking water were equal; Ramı´ rez-Ca´rdenas et al (2008) found higher contents of zinc and iron in unsoaked beans and calcium and copper in beans cooked with the soaking water Elmaki et al (2007) found that increasing the soaking length of beans or discarding the soaking water resulted in greater loss of minerals However, these treatments were also associated with greater HCl-extractability Thus, although minerals are lost in the soaking water, soaking and discarding the soaking water increases the bioavailability of the minerals that remained in the beans This is probably caused by a reduction of antinutrients that chelate minerals, as they are also reduced when beans are soaked and the soaking water discarded Studies with other types of beans and legumes also found differing mineral contents Huma et al (2008) found that soaking and cooking can reduce the amount of minerals significantly Granito et al (2007) observed that there was a greater loss of calcium, magnesium, potassium, zinc and iron in cooked beans than in soaked beans cooked without the soaking water However, minerals lost during cooking lixiviate to the cooking water; (Huma et al., 2008) consequently, bean preparations consumed with the cooking water retain those minerals Meanwhile, Chopra & Sankhala (2004) found that soaking decreases the tannin and phytate contents of horse gram (D biflorus) and moth bean (P aconitifolius), but calcium and magnesium contents are not reduced significantly by dissolution; the digestibility and metabolism of both minerals also increased with soaking Aranda et al (2004) also observed that soaking and discarding the soaking water decreases tannin and phytate contents, which improves iron bioavailability Hence, studies with legumes in general and this review are concordant regarding mineral bioavailability: it increases with soaking, especially when the soaking water is discarded and is associated with a reduction of antinutritional factors Carbohydrates As observed with proteins, studies are not concordant in relation to carbohydrate content Ramı´ rez-Ca´rdenas et al (2008) found a greater carbohydrate content in unsoaked, cooked beans and lower content in beans cooked with the soaking water; however, statistical analyses were not done In relation to starch fractions, Carmona-Garcı´ a et al (2007) found greater proportions of total starch and available starch in beans cooked without the soaking water, considering the average found for samples soaked in different solutions There were divergences regarding resistant starch: a sodium chloride (NaCl) solution was more effective in reducing resistant starch than a sodium bicarbonate (NaHCO3) solution In both cases, the beans were cooked without the soaking water The starch, amylopectin and resistant starch contents of raw beans and the amylose content of soaked beans were higher than those of beans cooked without the soaking water (Pujola` et al., 2007) However, these results are not relevant because beans are not eaten raw, or soaked without subsequent cooking Different results were also obtained by other authors while studying the carbohydrate content of beans Oliveira et al (2001b) found that cooking soaked common beans without the soaking water reduced the starch content by 26.8% Salgado et al (2005) found a greater resistant starch content in macassar beans (Vigna unguiculata L Walp) when they were soaked but cooked without the soaking water Kutosˇ et al (2003) found that unsoaked, cooked beans and soaked beans cooked without the soaking water had equal resistant starch contents The authors of the two studies (Kutosˇ et al., 2003; Salgado et al., 2005) did not investigate beans cooked with the soaking water In agreement with Pujola` et al (2007), Oliveira et al (2001b) found that soaking associated or not with cooking, slightly reduced the starch content of beans Additionally, Apata (2008) states that cooking reduces the carbohydrate content even if the beans are not previously soaked Other authors second the influence of cooking on starch content and also mention other factors that influence starch content, such as postcooking handling, cooking method, bean variety, maturation stage of the seeds and length of time stocked frozen (Osorio-Dı´ az et al., 2002 and Salgado et al., 2005) Most authors agree that cooking without the soaking water reduces the carbohydrate content of beans, but resistant starch content remains unchanged, which is desirable as resistant starch resembles soluble fibre (Salgado et al., 2005) If only starch is taken into account, it would not be recommended to cook soaked beans without the soaking water However, when all carbohydrates are considered, it may be advantageous to discard the soaking water, as this reduces the contents of undesirable sugars, such as sucrose and the oligosaccharides that cause flatulence Fibres Unsoaked beans and beans cooked with the soaking water seem to have more fibre than beans cooked Ó 2010 The Authors International Journal of Food Science and Technology Ó 2010 Institute of Food Science and Technology International Journal of Food Science and Technology 2010 2215 2216 Soaking and nutritional quality of beans A C Fernandes et al without the soaking water However, when soluble and insoluble fibre fractions are analysed separately, their contents vary in beans cooked with or without the soaking water (Ramı´ rez-Ca´rdenas et al., 2008; Toledo & Canniatti-Brazaca, 2008) Rehman & Shah (2004) studied soaked beans cooked without the soaking water and found that the cellulose, hemicellulose and lignin contents were higher when the beans were soaked in a sodium bicarbonate solution (NaHCO3) and cooked in a microwave oven or regular pot According to Kutosˇ et al (2003), soaking and cooking pinto beans increase soluble fibre content, but a higher increase was found in unsoaked, cooked beans On the other hand, processing decreased the insoluble fibre content, which was less affected by cooking without the soaking water than by cooking without soaking Total fibre content decreased discretely and was less affected by cooking without soaking, as found by Vidal-Valverde et al (1998) in their study with faba beans (V faba L major) For this reason, Kutosˇ et al (2003) believe that it is better not to soak beans to maintain total fibre content It is important to emphasise that resistant starch content, which resembles soluble fibre, was similar between unsoaked, cooked beans and cooked beans without the soaking water (Kutosˇ et al., 2003) Chopra et al (2009) studied five different types of uncooked legumes where the soaking water was discarded and found that all fibre fractions increased with soaking, Thus, legume soaking is beneficial to health because it increases the dietary fibre content, especially soluble fibre content Considering the findings on nutrients and antinutrients covered in the studies, the different effects of prepreparation and preparation are summarised in Table S3 Conclusion The articles reviewed in this paper are based on studies that analyse the soaking of common beans (P vulgaris L.) in water or other solutions (e.g sodium bicarbonate, sodium chloride, acetic acid) to reduce the antinutritional and flatulence factors, as well as to increase nutrient availability They also investigated if the losses were significant during the preparation processes The results of these articles were systematically analysed by comparing the statistically analysed data Discarding the soaking water before cooking was found to be advantageous This procedure seems to reduce some carbohydrate fractions of beans and can reduce, maintain or increase fibre content Meanwhile, resistant starch content remains unchanged, whose function is similar to that of soluble fibres This method also reduced phytates, phytic acid, total phenolic compounds and tannins Even though mineral content was International Journal of Food Science and Technology 2010 also reduced, the bioavailability of most studied minerals increased Furthermore, the different preparation methods not seem to affect the protein content and digestibility of the studied beans Soaking before cooking and discarding the soaking water also seems to be an effective way to reduce the amounts of oligosaccharides that cause flatulence This is an important issue because an excess of these oligosaccharides can lead an individual to avoid eating beans altogether, because of the intestinal discomfort So, despite the fact that these compounds present some functional properties, if beans are not consumed to avoid intestinal discomfort, these compounds will also not be consumed and their benefits will not be enjoyed It should be emphasised that although thermal processing of beans is by far the factor that most reduces antinutrient and nutrient contents, beans are not eaten raw, especially because they contain toxic substances, so cooking is mandatory Finally, the contents of the analysed compounds in beans can be affected by bean variety, crop location and stocking and distribution methods As these factors will always be present, we suggest that beans should always be soaked and the soaking water discarded before cooking when preparing beans to improve their nutritional quality References Anton, A.A., Ross, K.A., Beta, T., Gary Fulcher, R & Arntfield, S.D (2008) Effect of pre-dehulling treatments on some nutritional and physical properties of navy and pinto beans (Phaseolus vulgaris L.) LWT – Food Science and Technology, 41, 771–778 Apata, D.F (2008) Effect of cooking methods on available and unavailable carbohydrates of some tropical grain legumes African Journal of Biotechnology, 7, 2940–2945 Aranda, P., Lo´pez-Jurado, M., Fernande´z, M., Moreu, M.D.C., Porres, J.M & Urbano, G (2004) Bioavailability of calcium and magnesium from faba beans (Vicia faba L var major), soaked in different pH solutions and cooked, in growing rats Journal of the Science of Food and Agriculture, 84, 1514–1520 Boateng, J., Verghese, M., Walker, L.T & Ogutu, S (2007) Effect of processing on antioxidant contents in selected dry beans (Phaseolus spp L.) LWT – Food Science and Technology, 41, 1541–1547 Campos-Vega, R., Reynoso-Camacho, R., Pedraza-Aboytes, G et al (2009) Chemical composition and in vitro polysaccharide fermentation of different beans (Phaseolus vulgaris L.) Journal of Food Science, 74, T59–T65 Carmona-Garcı´ a, R., Osorio-Dı´ az, P., Agama-Acevedol, E., Tovar, J & Bello-Pe´rez, L.A (2007) Composition and effect of soaking on starch digestibility of Phaseolus vulgaris (L.) cv ‘Mayocoba’ International Journal of Food Science and Technology, 42, 296–302 Chopra, S & Sankhala, A (2004) Effect of soaking and sprouting on tannin, phytate and in vitro iron in underutilized legumes – horse gram (Dolichos biflorus) and moth bean (Phaseolus aconitifolius) Journal of Food Science and Technology, 41, 547–550 Chopra, H., Sa, U & Ghugre, P (2009) Dietary fibre content of selected legumes: varietal differences and effect of processing Journal of Food Science and Technology, 46, 266–268 Elmaki, H.B., Abdelrahaman, S.M., Idris, W.H., Hassan, A.B., Babiker, E.E & El Tinay, A.H (2007) Content of antinutritional Ó 2010 The Authors International Journal of Food Science and Technology Ó 2010 Institute of Food Science and Technology Soaking and nutritional quality of beans A C Fernandes et al factors and HCl-extractability of minerals from white bean (Phaseolus vulgaris) cultivars: influence of soaking and ⁄ or cooking Food Chemistry, 100, 362–368 FAO FAOSTAT (2009) Consumption: Crops Primary Equivalent, Food and Agriculture Organisation Statistics Division Rome, Italy: FAO (Food and Agriculture Organisation of the United Nations) http://faostat.fao.org/site/609/default.aspx#ancor (last accessed 16 August 2010) Granito, M., Brito, Y & Torres, A (2007) Chemical composition, antioxidant capacity and functionality of raw and processed Phaseolus lunatus Journal of the Science of Food and Agriculture, 87, 2801–2809 Haro, A (1983) La calidad nutritiva de las leguminosas: grano y su control gene´tico In: Leguminosas de grano (edited by J.I Cubero & M.T Moreno) Pp 213–224 Madrid, Spain: Ediciones MundiPrensa Hemalatha, S., Platel, K & Srinivasan, K (2007) Zinc and iron contents and their bioaccessibility in cereals and pulses consumed in India Food Chemistry, 102, 1328–1336 Huma, N., Anjum, F.M., Sehar, S., Khan, M.I & Hussain, S (2008) Effect of soaking and cooking on nutritional quality and safety of legumes Nutrition and Food Science, 38, 570–577 Kutosˇ , T., Golob, T., Kacˇ, M & Plestenjak, A (2003) Dietary fibre content of dry and processed beans Food Chemistry, 80, 231– 235 Luthria, D.L & Pastor-Corrales, M.A (2006) Phenolic acids content of fifteen dry edible bean (Phaseolus vulgaris L.) varieties Journal of Food Composition and Analysis, 19, 205–211 Martı´ n-Cabrejas, M.A., Aguilera, Y., Pedrosa, M.M et al (2009) The impact of dehydration process on antinutrients and protein digestibility of some legume flours Food Chemistry, 114, 1063–1068 Matella, N.J., Dolan, K.D., Stoeckle, A.W., Bennink, M.R., Lee, Y.S & Uebersax, M.A (2005) Use of hydration, germination, and – galactosidase treatments to reduce oligosaccharides in dry beans Journal of Food Science, 70, C203–C207 Mosha, T.C.E & Vicent, M.M (2004) Nutritional value and acceptability of homemade maize ⁄ sorghum-based weaning mixtures supplemented with rojo bean flour, ground sardines and peanut paste International Journal of Food Sciences and Nutrition, 55, 301– 315 Muzquiz, M (2008) Conference: Componentes nutricionalmente activos en leguminosas: implicaciones en nutricio´n y salud In: Scientific memories – 1st International Scientific Congress and National Bean Fair (edited by A.C Herna´ndez) ISBN: 978-97043-0376-1 Pp 226–227 Celaya, Me´xico: Instituto Nacional de Investigaciones Forestales, Agr colas y Pecuarias Nergiz, C & Goăkgoăz, E (2007) Effects of traditional cooking methods on some antinutrients and in vitro protein digestibility of dry bean varieties (Phaseolus vulgaris L.) grown in Turkey International Journal of Food Science and Technology, 42, 868–873 Oliveira, A.C., Carraro, F., Reis, S.M.P.M et al (2001a) The elimination of the not absorved water during common bean soaking resulted in weight gain in rats Brazilian Journal of Nutrition, 14, 153–155 Oliveira, A.C., Queiroz, K.S., Helbig, E., Reis, S.M.P.M & Carraro, F (2001b) The domestic processing of the common bean resulted in a reduction in the phytates and tannins antinutritional factors, in the starch content and in the raffinose, stachiose and verbascose flatulence factors Archivos Latinoamericanos de Nutricio´n, 51, 276–283 Oliveira, A.C., Reis, S.M.P.M., Carvalho, E.M et al (2003) Increasing quantities of phytic acid in the diet did not affect casein digestibility and weight gain in rats Brazilian Journal of Nutrition, 16, 211–217 Oliveira, V.R., Ribeiro, N.D., Jost, E & Londero, P.M.G (2008) Nutritional and microbiological quality of common beans (Phaseolus vulgaris L.) cooked with or without the use of soaking water Revista Cieˆncia e Agrotecnologia, 32, 1912–1918 Osman, M.A (2007) Effect of different processing methods, on nutrient composition, antinutrional factors, and in vitro protein digestibility of Dolichos lablab bean [Lablab purpuresus (L) sweet] Pakistan Journal of Nutrition, 6, 299–303 Osorio-Dı´ az, P., Bello-Pe´rez, L.A., Agama-Acevedo, E., VargasTorres, A., Tovar, J & Paredes-Lo´pez, O (2002) In vitro digestibility and resistant starch content of some industrialized commercial beans (Phaseolus vulgaris L.) Food Chemistry, 78, 333– 337 Philippi, S.T., Latterza, A.R., Cruz, A.T.R & Ribeiro, L.C (1999) Adapted food pyramid: a guide for a right food choice Brazilian Journal of Nutrition, 12, 65–80 Pujola`, M., Farreras, A & Casan˜as, F (2007) Protein and starch content of raw, soaked and cooked beans (Phaseolus vulgaris L.) Food Chemistry, 102, 1034–1041 Ramı´ rez-Ca´rdenas, L., Leonel, A.J & Costa, N.M.B (2008) Effect of domestic processing on nutrient and antinutritional factor content in different cultivars of common beans Cieˆncia e Tecnologia de Alimentos, 28, 200–213 Ranilla, L.G., Genovese, M.I & Lajolo, F.M (2009) Effect of different cooking conditions on phenolic compounds and antioxidant capacity of some selected Brazilian bean (Phaseolus vulgaris L.) cultivars Journal of Agricultural and Food Chemistry, 57, 5734–5742 Rehman, Z.-U & Shah, W.H (2004) Domestic processing effects on some insoluble dietary fibre components of various food legumes Food Chemistry, 87, 613–617 Rehman, Z.U & Shah, W.H (2005) Thermal heat processing effects on antinutrients, protein and starch digestibility of food legumes Food Chemistry, 91, 327–331 Salgado, S.M., Melo Filho, A.B., Andrade, S.A.C., Maciel, G.R., Livera, A.V.S & Guerra, N.B (2005) Modification of the concentration of resistant starch in macassar bean (Vigna unguiculata L Walp) hydrothermal process and freezing Cieˆncia e Tecnologia de Alimentos, 25, 259–264 Shimelis, E.A & Rakshit, S.K (2005) Antinutritional factors and in vitro protein digestibility of improved haricot bean (Phaseolus vulgaris L.) varieties grown in Ethiopia International Journal of Food Sciences and Nutrition, 56, 377–387 Shimelis, E.A & Rakshit, S.K (2007) Effect of processing on antinutrients and in vitro protein digestibility of kidney bean (Phaseolus vulgaris L.) varieties grown in East Africa Food Chemistry, 103, 161–172 Siddiq, M., Nyombaire, G., Dolan, K.D., Matella, N.J & Harte, J.B (2006) Processing of sugar-coated red kidney beans (Phaseolus vulgaris): fate of oligosaccharides and phytohemagglutinin (PHA), and evaluation of sensory quality Journal of Food Science, 71, C521–C526 Silva, M.R & Silva, M.A.A.P (1999) Nutritional aspects of phytates and tannins Brazilian Journal of Nutrition, 12, 21–32 Silva, M.R & Silva, M.A.A.P (2000) Antinutritional factors: protease inhibitors and lectins Brazilian Journal of Nutrition, 13, 3–9 Teguia, A & Fon Fru, S (2007) The growth performances of broiler chickens as affected by diets containing common bean (Phaseolus vulgaris) treated by different methods Tropical Animal Health and Production, 39, 405–410 Toledo, T.C.F & Canniatti-Brazaca, S.G (2008) Chemical and nutritional evaluation of Carioca beans (Phaseolus vulgaris L.) cooked by different methods Cieˆncia e Tecnologia de Alimentos, 28, 355–360 Vadivel, V & Pugalenthi, M (2008) Effect of various processing methods on the levels of antinutritional constituents and protein digestibility of Mucuna pruriens (L.) DC var utilis (Wall ex Wight) Baker ex Burck (velvet bean) seeds Journal of Food Biochemistry, 32, 795–812 Vadivel, V & Pugalenthi, M (2009) Effect of soaking in sodium bicarbonate solution followed by autoclaving on the nutritional and Ó 2010 The Authors International Journal of Food Science and Technology Ó 2010 Institute of Food Science and Technology International Journal of Food Science and Technology 2010 2217 2426 Odorant compounds in Oloroso sherry wines L Zea et al browning is caused by different chemical reactions of condensation between phenols and ⁄ or their oxidation products (Oszmianski et al., 1988; Lopez-Toledano et al., 2004a; Merida et al., 2006), although the resulting increase in brown colour might also be because of the presence of Maillard reactions (Palacios et al., 2002) The aroma of wine, which is the result of a wide variety of compounds with a specific odorant impact, is among its most characteristic sensory attributes Taking into account that the odour activity values (OAVs) of a substance are defined as the ratio of odorant concentration to odour threshold, it can be reasonably assumed that the compounds with the highest OAVs will be those most strongly contributing to the overall aroma of wine (Gil et al., 2006; Selli et al., 2006; Vilanova & Sieiro, 2006; Chaves et al., 2007; Gomez-Miguez et al., 2007; Lasekan et al., 2007; Mun˜oz et al., 2007; Sanchez et al., 2007; Plutowska & Wardencki, 2008) These compounds with some odorant impact, in individual way or in groups of similar odour descriptors, considerably facilitate the analysis of the aroma profile of wine by appreciably reducing the number of variables to be examined Specifically, odorant series have recently been used as analytical tools (Moyano et al., 2002; Chaves et al., 2007; Mun˜oz et al., 2007; Zea et al., 2007, 2008) with a view to examining and ⁄ or comparing the aroma profiles for different types of sherry wines produced in Montilla-Moriles region (southern Spain) In this work, we studied changes in the active odorant compounds of Oloroso sherry type wines during their oxidative ageing, to identify the odorant series most markedly contributing to their aroma profile and estimate the significance of the active odorants synthesised by chemical pathways from ethanol during the process Materials and methods Wines Oloroso sherry type wines (grape cv Pedro Ximenez) obtained by industrial oxidative ageing for 0, 3, 6, and 14 years were used Because the concept of vintage is not applicable to sherry wines, the ageing times were calculated following commercial criteria (by considering the age and volume of the mixed wines in the ‘criaderas and solera’ system) The wine samples were chosen as more representatives by the Quality Regulation Board of the Montilla-Moriles designation of origin among the wines produced in fifteen cellars from this region One sample for each ageing degree was taken of each cellar All wines of the same ageing degree were mixed and immediately analysed by triplicate The Oloroso wine is produced by the typical industrial ageing process, known as ‘criaderas and solera’, in American oak casks The cask wood has about 25 years old, with a medium International Journal of Food Science and Technology 2010 toasted level The American oak wood has a high density, and low porosity and permeability Experimental analyses Oenological variables The ethanol was quantified by the Crowell & Ough (1979) method The titratable and volatile acidities were determined according to the European Community Official Analytical Methods (1990) The absorbance values were obtained in a Perkin–Elmer Lambda 25 model spectrophotometer (PerkinElmer Life and Analytical Sciences, Shelton, CT, USA) at 280, 420 and 520 nm on 10 -mm path length quartz cells Perception thresholds and aroma descriptors A panel of thirty-three volunteer panellists of both sexes (thirteen women and twenty men) between 20 and 55 years old from the University of Cordoba participated in the study Thirteen judges of the abovementioned panel had previous experience in sherry wine sensory evaluation However, all judges were trained in preliminary sessions as described in Ferreira et al (2003) Reference standards taken from Sigma-Aldrich (Munich, Germany) and from ‘Le nez du vin’ (Jean Lenoir, Provence, France) were presented (five per session) During the training, judges discussed about odour terms and modified it by eliminating terms they considered irrelevant or redundant and by adding terms their considered pertinent For the determination of the perception, thresholds samples were prepared 30 before the test, to allow time for the vapour pressure to reach equilibrium at ambient temperature The odour substances (1 mL) are poured directly into the glass flasks containing a piece of cotton and were closed immediately Judges evaluated five aroma compounds per session (fourteen sessions) by direct method of smelling The concentration levels of the odorant solutions used were prepared according to annex A (ISO 5496) Starting from the lowest concentration solution, the judges indicated the first solution with an odorant sensation different to the perceived in the control (14% v ⁄ v ethanol ⁄ water), according to the annex B (ISO 5496) standard This sensation must be detected by at least 50% of the judges in a taste panel In addition, the judges were asked for the aroma descriptors and the responses were compiled for all twenty-two aroma compounds and those odour descriptors cited by less than 15% of the panel were eliminated Perception thresholds and odour descriptors are listed in Table Identification and quantification of aroma compounds Each one of the twenty-two aroma compounds analysed was identified by means of its retention time, coeluted with a standard solution of commercial product and Ó 2010 The Authors International Journal of Food Science and Technology Ó 2010 Institute of Food Science and Technology Odorant compounds in Oloroso sherry wines L Zea et al confirmed by mass spectrometry (Hewlett-Packard 5972 MSD, Palo Alto, CA, USA) Positive ion electron impact mass spectra were acquired in scan mode, with a range of m ⁄ z 39–300, and scan rate of 1.6 scan s)1 The chromatographic column, injector and oven temperatures, carrier gas and its flow were the same that those used for the quantification, as described below The volatile compounds were quantified by capillarycolumn gas chromatography after continuous extraction of 100 mL of wine sample with 100 mL of freon-11 for 24 h Previously, wine was adjusted to pH 3.5 and mL of internal standard (30 mg L)1 of 2-octanol) was added The freon extract containing the volatile compounds was concentrated to 0.2 mL in a KudernaDanish microconcentrator and lL was injected into a Hewlett-Packard-5890 series II gas chromatograph equipped with an HP-INNOWax fused silica capillary column (60 m · 0.32 mm ID, 0.25 lm film thickness), with a FID and a sniffing port connected by a flow splitter to the column exit The oven temperature programme was as follows: at 45 °C, °C min)1 ramp to 185 °C and 30 at 185 °C Injector and detector temperatures were 275 and 300 °C, respectively The carrier gas was helium at 70 kP and split 1:30 The quantification was made by using chromatographic response factors, calculated for each compound in relation to the internal standard, in standard solutions of commercial products supplied by Sigma-Aldrich Acetaldehyde was quantified by using the enzymatic test from R-Biopharm (Darmstadt, Germany) Gas chromatography-olfactometry analysis The sniffing port was an Olfactory detector, part No 093500 (SGE-International, Ringwood, Australia) connected by a flow splitter to the column exit The GC effluent was split 1:2 between the FID and the sniffing port Humidified air was added in the sniffing port at 33 mL min)1 All the chromatographic conditions were the same to quantification of volatile compounds above described Three trained judges, one woman and two men, selected for their ability to generate accurate terms as well as experienced in gas chromatography-olfactometry analysis (GC-O) sherry wines, performed the sniffing of the extracts Sniffings were carried out during 140 min, with a maximum time of 15 per judge Samples were sniffed at least two times, one session per day, and retention times and odour intensity were recorded Judges were asked to quantify the intensity of each odour in simple terms use a 3-point category scale (i, intense odour; w, weak odour; np, not perceived) Statistical procedures Principal components and simple regression analyses were carried out by using the StatgraphicsÔ 5.0 (STSC Inc., Rockville, MD, USA) computer program )1 Table Retention times (Rt), odour descriptors, odorant series and thresholds (mg L ) of the aroma compounds (odour activity values > 1) identified in Oloroso sherry type wine Rt Compound Odour descriptors Odorant seriesa Threshold – 9.24 9.66 10.63 11.40 12.05 13.98 15.34 20.38 21.83 28.47 33.75 41.09 67.02 77.08 86.36 92.59 96.30 103.6 108.1 123.8 160.5 Acetaldehyde Ethyl acetate 1,1-Diethoxyethane Ethyl isobutanoate 2,3-Butanedione Ethyl butanoate Isobutanol Isoamyl acetate Isoamyl alcohols Ethyl hexanoate Acetoin Ethyl lactate Ethyl octanoate 2,3-Butanediol Methionol Phenethyl acetate Ethyl furoate Phenethyl alcohol Z-Oak lactone 4-Ethylguaiacol Eugenol Sotolon Overripe apple Pineapple, varnish, balsamic Green fruit, licorice Strawberry, melon Butter Banana, pineapple, strawberry Alcohol, wine like, nail polish Banana Alcohol, nail polish Banana, green apple Buttery, cream Strawberry, raspberry, buttery Pineapple, pear Buttery, creamy Cooked potato, cut hay Rose, honey Glue, paint Rose, honey Coconut, burnt woody, vanilla Toasted bread, smoky, clove Cinnamon, clove Walnut, candyfloss, curry 1, 1, 2 1, 1, 7 1, 6, 1, 10 7.5 0.015 0.1 0.020 40 0.030 65 0.005 30 100 0.002 668 0.5 0.25 10 0.035 0.046 0.005 0.005 a 2, 3 5 6, 8 6, 1, fruity; 2, chemical; 3, balsamic; 4, vegetable; 5, fatty; 6, empyreumatic; 7, floral; 8, spicy Ó 2010 The Authors International Journal of Food Science and Technology Ó 2010 Institute of Food Science and Technology International Journal of Food Science and Technology 2010 2427 2428 Odorant compounds in Oloroso sherry wines L Zea et al Results and discussion Table shows the odour descriptors, odorant series and thresholds of the aroma compounds with odour activity values (OAVs > 1) in Oloroso sherry type wine Although the odour descriptors and thresholds of the compounds can be obtained by scan of bibliographical sources, the high content in ethanol of the studied wines recommended their determination by a panel on 14% (v ⁄ v) ethanol solutions of each compound The odorant compounds with similar odour descriptor were grouped into eight odorant series (fruity, chemical, balsamic, vegetable, fatty, empyreumatic, floral and spicy) These series were chosen by adapting the Wine Aroma Wheel terms to de peculiar aroma of sherry wines, according to criteria adopted in previous works Table shows the ethanol content, titratable and volatile acidities, and absorbances at 280, 420 and 520 nm of the studied wines after 0, 3, 6, and 14 years of oxidative ageing As can be seen, ethanol exhibited a slight concentrating effect during ageing that can be mainly attributed to evaporation of water from the wine On the other hand, the increases in titratable and volatile acidities were the result of acetic acid production from ethanol and acetaldehyde of wine The absorbance at 280 nm increased with time by effect of the gradual extraction of phenolic compounds from the oak wood and ⁄ or the possible changes in molar absorptivity coefficient of the brown polymers in relation to their precursor compounds (Lopez-Toledano et al., 2004b) The contents in brown- and red-coloured compounds, measured as A420 and A520, respectively, revealed gradual increased formation of phenolic polymers during the oxidative ageing process until years, maintaining their values with oscillations from this point up to 14 years Table shows the twenty-two compounds with OAV > in some point during the ageing process In brackets are shown the results obtained by sniffing, being these perceptions ranked as intense or weak As can be seen, most of the studied compounds were perceived throughout the ageing process, excepted for isobutanol, acetoin, 2,3-butanediol and ethyl furoate that were undetectable by sniffing throughout ageing The most active odorants in the 14-year-old wines (those of the highest quality) were ethyl butanoate, ethyl octanoate and sotolon, all with an OAV > 50 and showing intense perception by sniff The contents in the former two compounds increased through chemical esterification of ethanol with butanoic and octanoic acids, respectively, and contributed essentially with fruity notes to the wine Sotolon is a c-lactone synthesised by reaction of acetaldehyde with a-ketobutyric acid formed from the biochemical deamination of threonine (Pham et al., 1995) Sotolon is widely documented to contribute nutty, curry and candyfloss notes to wine aroma Acetaldehyde, and its derivatives 1,1-diethoxyethane and 2,3-butanedione, showed medium OAVs (between 10 and 50) and intense olfactometry perception The 1,1-diethoxyethane is an acetal resulting from the reaction of one acetaldehyde molecule with two ethanol molecules On the other hand, it is possible that 2,3-butanedione results from the oxidation of acetoin previously formed by condensation of two acetaldehyde molecules Other compounds with medium OAVs, and intensely perceived, were ethyl isobutanoate, ethyl hexanoate, ethyl acetate, eugenol and Z-oak lactone All others compounds exhibited OAV less than 10, although in most cases showed intense perception by sniff Table lists a perception index (PI) for each studied compound at the end of the oxidative ageing process Such an index was calculated as the ratio of the perceived intensity after 14 years of ageing to that at the beginning of the process The theoretical perceived intensity of each compound, w, was calculated from Stevens’ law (Mayol & Acree, 2001), w = kun, where w is the perceived intensity, k is a constant for each compound, u the stimulus (OAV) and n the Stevens’ exponent (0.6) As can be seen, the compound exhibited most markedly increasing in PI was Z-oak lactone, which comes from casks wood (Maga, 1996) The ethyl Ageing time (years) Ethanol (% v ⁄ v) Titratable aciditya Volatile acidityb A280 (a.u.)c A420 (a.u.) A520 (a.u.) 14 18.21 ± 0.06 4.75 ± 0.01 0.32 ± 0.03 0.185 ± 0.001 0.522 ± 0.001 0.139 ± 0.001 19.0 ± 0.1 4.90 ± 0.01 0.38 ± 0.01 0.279 ± 0.001 0.591 ± 0.001 0.177 ± 0.001 19.8 ± 0.1 5.32 ± 0.01 0.49 ± 0.04 0.399 ± 0.001 1.182 ± 0.001 0.396 ± 0.001 19.3 ± 0.1 5.35 ± 0.01 0.49 ± 0.03 0.348 ± 0.001 0.908 ± 0.001 0.292 ± 0.001 20.1 ± 0.1 5.58 ± 0.01 0.73 ± 0.01 0.435 ± 0.001 1.171 ± 0.001 0.354 ± 0.001 Table Oenological variables of Oloroso sherry type wine during the oxidative ageing The values are given by the means and standard deviations (n = 3) g tartaric acid L)1 g acetic acid L)1 c Dilution 1:50 a b International Journal of Food Science and Technology 2010 Ó 2010 The Authors International Journal of Food Science and Technology Ó 2010 Institute of Food Science and Technology Odorant compounds in Oloroso sherry wines L Zea et al Table Means and standard deviations (n = 3) for the odour activity values of the odorant active compounds in oloroso sherry type wine during the oxidative ageing In bracket is indicated the intensity of the perception by sniff (i, intense; w, weak; np, not perceived) The perception index (PI) for each compound was calculated as the ratio between the odorant intensity perceived at 14 years and the corresponding to unaged wines (0 years), according to the Stevens’ law Ageing time (years) Compounda 14 PI Acetaldehyde Ethyl acetate 1,1-Diethoxyethane Ethyl isobutanoate 2,3-Butanedione Ethyl butanoate Isobutanol Isoamyl acetate Isoamyl alcohols Ethyl hexanoate Acetoin Ethyl lactate Ethyl octanoate 2,3-Butanediol Methionol Phenethyl acetate Ethyl furoate Phenethyl alcohol Z-Oak lactone 4-Ethylguaiacol Eugenol Sotolon 7.5 ± 0.3 (i) ± (i) ± (i) 30 ± (i) 13.9 ± 0.2 (i) 4.9 ± 0.6 (i) 1.1 ± 0.1 (np) 7.8 ± 0.5 (i) 10.4 ± 0.1 (i) ± (i) 0.3 ± 0.1 (np) 1.19 ± 0.08 (i) 14 ± (i) 1.20 ± 0.06 (np) ± (i) 0.31 ± 0.06 (i) 0.53 ± 0.06 (np) 6.6 ± 0.4 (i) 0.5 ± 0.2 (w) 3.0 ± 0.1 (i) ± (i) 19 ± (w) ± (i) 12.5 ± 0.3 (i) 8.3 ± 0.3 (i) 35 ± (i) 46 ± (i) 24 ± (i) 1.09 ± 0.03 (np) 4.4 ± 0.4 (i) 10.1 ± 0.2 (i) 29.2 ± 0.7 (i) 1.03 ± 0.08 (np) 3.01 ± 0.04 (i) 35 ± (i) 1.30 ± 0.07 (np) 6.6 ± 0.6 (i) 0.4 ± 0.2 (i) 1.1 ± 0.3 (np) 5.6 ± 0.3 (i) 1.0 ± 0.6 (w) ± (i) 29.1 ± 0.6 (i) 23.1 ± 0.7 (w) 8.1 ± 0.5 (i) 18 ± (i) ± (i) 28 ± (i) 35 ± (i) 31 ± (i) 1.17 ± 0.01 (np) 5.3 ± 0.3 (i) 10.0 ± 0.5 (i) 27 ± (i) 1.1 ± 0.3 (np) 3.3 ± 0.1 (i) 52 ± (i) 1.7 ± 0.3 (np) 2.2 ± 0.4 (i) 1.4 ± 0.3 (i) 0.41 ± 0.08 (np) 4.9 ± 0.8 (i) 3.0 ± 0.7 (i) ± (w) 28 ± (i) 24 ± (i) 8.9 ± 0.6 (i) 19.4 ± 0.8 (i) ± (i) 33.9 ± 0.4 (i) 41 ± (i) 42 ± (i) 1.15 ± 0.05 (np) ± (i) 9.6 ± 0.2 (i) 31 ± (i) 0.90 ± 0.07 (np) 3.1 ± 0.2 (i) 57.3 ± 0.3 (i) 1.7 ± 0.2 (np) 2.1 ± 0.3 (i) 1.52 ± 0.02 (i) 1.08 ± 0.02 (np) 5.1 ± 0.5 (i) 3.74 ± 0.09 (i) 2.6 ± 0.4 (w) 27 ± (i) 33 ± (i) 11 ± (i) 28 ± (i) 14 ± (i) 39.3 ± 0.9 (i) 46 ± 11 (i) 67 ± 10 (i) 1.09 ± 0.01 (np) ± (i) 9.0 ± 0.9 (i) 38 ± (i) 1.0 ± 0.1 (np) 3.64 ± 0.04 (i) 63 ± (i) 2.1 ± 0.4 (np) 1.9 ± 0.5 (i) 2.3 ± 0.1 (i) 1.1 ± 0.4 (np) 5.6 ± 0.1 (i) 11 ± (i) 2.3 ± 0.1 (w) 20 ± (i) 57 ± (i) 1.26 2.12 1.66 1.18 2.05 4.80 0.995 1.02 0.917 3.03 2.06 1.96 2.47 1.40 0.422 3.39 1.55 0.906 6.39 0.853 1.43 1.93 The compounds are arranged by retention time butanoate, phenethyl acetate and ethyl hexanoate also exhibited high PI values at the end of wine ageing By contrast, isoamyl alcohols, methionol, phenethyl alcohol and 4-ethylguaiacol showed the lowest PI To more easily observe the aroma profile of the wine during ageing, the OAVs for the eighteen compounds detected by sniff were grouped by their common descriptors into eight series (Table 1) Figure shows the variation of the OAVs for the major odorant series (OAV > 50) during the ageing process As can be seen, the fruity series was exhibiting the highest OAVs throughout, with a final value close to 350, and was followed by the fatty and spicy series (OAVs about 100), and empyreumatic series (OAVs about 70) In addition, the fruity series grouped the greatest number of compounds and exhibited a high correlation with the ageing time (r2 = 0.9628) Therefore, this series could be considered as most representative of the changes in aroma profile during the ageing of Oloroso wine Figure shows the variation of the OAVs for the minor odorant series (OAV < 50) As can be seen, the chemical and balsamic series evolved similarly during the ageing process, reaching final values about 40 On the other hand, the floral series and, especially, the 400 Fruity Fatty Spicy Empyreumatic 300 OAVs a 200 100 0 14 Aging years Figure Changes for the odour activity values (OAVs) of the major odorant series (OAVs > 50) during the oxidative ageing of the Oloroso wines vegetable series were those less contributors to aroma profile, the latter even lost odorant activity as ageing progressed This result not detract from the sensory properties of the wines because these aromas are associated to typically unpleasant odours such as baked potato, cut hay or grass Ó 2010 The Authors International Journal of Food Science and Technology Ó 2010 Institute of Food Science and Technology International Journal of Food Science and Technology 2010 2429 Odorant compounds in Oloroso sherry wines L Zea et al 50 Table Means and standard deviations (n = 3) for the odour activity values of the odorant groups according to the chemical origin of the compounds included into them Chemical Balsamic 40 Floral Vegetable Ageing time (years) OAVs 30 20 10 0 Odorant groups 14 Ethyl esters Acetaldehyde Cask wood Alcohols Other non-ethyl esters 139 ± 13 86 ± 36 ± 22.3 ± 0.8 4.8 ± 0.4 159 ± 10 76 ± 36 ± 17.1 ± 0.9 6.7 ± 0.6 187 ± 91 ± 33 ± 16.7 ± 0.4 8±1 239 ± 127 ± 15 33 ± 16.4 ± 0.8 10 ± 64 ± 46 ± 12 ± 24 ± 8.1 ± 0.4 14 Aging years Figure Changes for the odour activity values (OAVs) of the minor odorant series (OAVs < 50) during the oxidative ageing of the Oloroso wines PC2 (6.6%) 2430 0 Year Years Years Years 14 Years –1 –2 –5 –4 –3 –2 –1 PC1 (87.0%) Figure Principal components analysis performed on the eight odorant series describing the aroma of the studied wines To better observe the contribution of the series to the different levels of ageing, the OAVs for the eight odorant series were subjected to principal components analysis (PCA) As can be seen from Fig 3, the first two PCs jointly accounted for 93.6% of the variance and the first alone for 87% Based on the scores for this last component, which was essentially influenced by the fruity, chemical and balsamic series (variables with the highest statistical weights), the wines can be classified according to ageing time, although no clear-cut distinction can be made between wines aged for and years In any case, the aromas included in the above-described series can reasonably be used as indices to evaluate the degree of ageing (quality) of these wines On the other hand, it is useful to know the chemical origin of the compounds that play an important role in the aroma profile of Oloroso wines, to assess possible changes in some odorant properties during the wine ageing In this sense, five major groups of odorants were International Journal of Food Science and Technology 2010 established according to their chemical and ⁄ or source origin in the wine One such group consisted of ethyl (acetate, isobutanoate, butanoate, hexanoate, lactate and octanoate) esters, which contributed to fruity notes mainly The second group consisted of other non-ethyl esters (isoamyl acetate, and phenethyl acetate), which can be ascribed to fruity, chemical, fatty and floral notes The third group was that of compounds coming from cask wood and included Z-oak lactone, 4-ethylguaiacol and eugenol (Singleton, 1995; Maga, 1996; Perez-Coello et al., 1997), which contribute mainly to empyreumatic and spicy notes The acetaldehyde group comprised these compounds, 1,1-diethoxyethane, 2,3butanedione and sotolon, contributing to fruity, balsamic, fatty, empyreumatic and spicy notes Finally, the alcohol group consists of isoamyl alcohols, methionol and phenethyl alcohol, exhibiting chemical, fruity, floral and vegetable notes The remaining four compounds (isobutanol, acetoin, 2,3-butanediol and ethyl furoate) were included in none of the previous groups because they were undetected by sniffing Because ethanol plays a role in the formation of ethyl esters and also in the production of acetaldehyde, and indirectly on some of its derivatives, these two groups were highly correlated (r2 = 0.8738) Table shows the variation of the OAVs for the five above-described groups during ageing of the wine As can be seen, the ethyl esters exhibited the highest OAVs from the beginning and reached a final mean value of 239 They were followed by the acetaldehyde group, which a mean OAV of 127 in the 14-year-old wines Odorant activity in this group changed little between the third and ninth year of ageing, but increased markedly at the beginning and end of the oxidative ageing The compounds from cask wood exhibited an OAV of 33, without significant changes after the third year Finally, taking into account, the five odorant groups established, the alcohols and the other non-ethyl esters accounted for only 6% of odorant activity in the oldest wines, the last exhibiting an irregular variation and the latter virtually without change during the ageing process Ó 2010 The Authors International Journal of Food Science and Technology Ó 2010 Institute of Food Science and Technology Odorant compounds in Oloroso sherry wines L Zea et al Summarising twenty-two active odorants (OAV > 1) in the Oloroso wines were studied, eighteen of them detected by GC-O Of which ethyl butanoate, ethyl octanoate and sotolon were the most active odorants The OAVs of the eight odorant series established by grouping the eighteen olfactometry detected compounds showed the fruity and vegetable series as those with the highest and lowest OAVs, respectively, throughout the ageing On the other hand, the fruity, chemical and balsamic series were those best discriminating between wines of different age in terms of aroma, which was very similar in the wines aged for and years, however Finally, the compounds related to the chemical activity of ethanol (ethyl esters plus acetaldehyde and its derivatives) increased in odorant significance in a higher proportion than those not synthesised from this alcohol (non-ethyl esters, alcohols and compounds from cask wood) during the ageing process In conclusion, the use of odorant series allows more accurately to determine de degree of oxidative ageing in relation to its time of duration, with a view to ensuring maximal standardization in the commercial product Acknowledgement This work was supported by a grant from the Spain Government (AGL 2006 04285) References Chaves, M., Zea, L., Moyano, L & Medina, M (2007) Changes in color and odorant compounds during oxidative aging of Pedro Ximenez sweet wines Journal of Agricultural and Food Chemistry, 55, 3592–3598 Crowell, E.A & Ough, C.S (1979) A modified procedure for alcohol determination by dichromate oxidation American Journal of Enology and Viticulture, 30, 61–63 E.E.C (1990) Official Report of the European Community Madrid, Spain: Mundi Prensa Fabios, M., Lopez-Toledano, A., Mayen, M., Merida, J & Medina, M (2000) Phenolic compounds and browning in sherry wines subjected to oxidative and biological aging Journal of Agricultural and Food Chemistry, 48, 2155–2159 Ferreira, V., Pet’ka, J., Aznar, M & Cacho, J (2003) Quantitative gas-chromatography-olfactometry Analytical characteristics of a panel of judges using a simple quantitative scale as gas chromatography detector Journal of Chromatography A, 1002, 169–178 Gil, M., Cabellos, J.M., Arroyo, T & Prodanov, M (2006) Characterization of the volatile fraction of young wines from the Denomination of Origin ‘‘Vinos de Madrid’’ (Spain) Analytica Chimica Acta, 563, 145–153 Gomez-Miguez, M.J., Cacho, J.F., Ferreira, V., Vicario, I.M & Heredia, F.J (2007) Volatile component of Zalema white wines Food Chemistry, 100, 1464–1473 Lasekan, O., Buettner, A & Christlbauer, M (2007) Investigation of important odorants of palm wine (Elaeis guineensis) Food Chemistry, 105, 15–23 Lopez-Toledano, A., Mayen, M., Merida, J & Medina, M (2004a) Optimization of the operating conditions for color correction in white wines based on the use of yeast as fining agent Journal of Food Science, 69, 599–603 Lopez-Toledano, A., Villan˜o-Valencia, D., Mayen, M., Merida, J & Medina, M (2004b) Interaction of yeasts with the products resulting from the condensation reaction between (+)-catechin and acetaldehyde Journal of Agricultural and Food Chemistry, 52, 2376–2381 Maga, J (1996) Oak lactones in alcoholic beverages Food Reviews International, 12, 105–130 Mayol, A & Acree, T (2001) Advances in gas chromatographicolfactometry In: Gas Chromatographic-Olfactometry The State of the Art (edited by J Leland, P Schieberle, A Buettner & T Acree) Pp 1–10 Washington, DC: American Chemical Society Merida, J., Lopez-Toledano, A & Medina, M (2006) Influence of aerobic and anaerobic conditions and yeasts on the reaction between (+)-catechin and acetaldehyde European Food Research and Technology, 222, 451–457 Mosedale, J.R (1995) Effects of oak wood on the maturation of alcoholic beverages with particular reference to whisky Forestry, 68, 203–230 Moyano, L., Zea, L., Moreno, J & Medina, M (2002) Analytical study of aromatic series in sherry wines subjected to biological aging Journal of Agricultural and Food Chemistry, 50, 7356–7361 Mun˜oz, D., Peinado, R.A., Medina, M & Moreno, J (2007) Biological aging of sherry wines under periodic and controlled microaerations with Saccharomyces cerevisiae var capensis: effect on odorant series Food Chemistry, 100, 1188–1195 Nishimura, K.M., Ohnishi, M., Masuda, M., Koga, K & Matsuyama, R (1983) Reactions of wood components during maturation In: Flavour of Distilled Beverages: Origin and Development (edited by J.R Piggott) Pp 241–255 London, UK: Society of Chemical Industry Ortega, A.F., Lopez-Toledano, A., Mayen, M., Merida, J & Medina, M (2003) Changes in color and phenolic compounds during oxidative aging of sherry white wine Journal of Food Science, 68, 2461–2468 Oszmianski, J., Ramos, T & Bourzeix, M (1988) Fractionation of phenolic compounds in red wines American Journal of Enology and Viticulture, 39, 259–262 Palacios, V., Valcarcel, M., Caro, I & Perez, L (2002) Chemical and biochemical transformations during the industrial process of Sherry vinegar aging Journal of Agricultural and Food Chemistry, 50, 4221– 4225 Perez-Coello, M.S., Sanz, J & Cabezudo, M.D (1997) Analysis of volatile components of oak wood by solvent extraction and direct thermal desorption-gas chromatography-mass spectrometry Journal of Chromatography A, 778, 427–434 Pham, T.T., Guichard, E., Schlich, P & Charpentier, C (1995) Optimal conditions for the formation of sotolon from a-ketobutyric acid in the French vin jaune Journal of Agricultural and Food Chemistry, 43, 2616–2619 Plutowska, B & Wardencki, W (2008) Application of gas chromatography-olfactometry (GC-O) in analysis and quality assessment of alcoholic beverages – a review Food Chemistry, 107, 449–463 Rous, C & Anderson, B (1983) Phenolic extraction curves for white wine aged in French and American oak barrels American Journal of Enology and Viticulture, 34, 211–215 Sanchez, E., Diaz-Maroto, M.C., Gonzales-Vin˜as, M.A., SorianoPerez, A & Perez-Coello, M.S (2007) Aroma profile of wines from Albillo and Muscat grape varieties at different stages of ripening Food Control, 18, 398–403 Selli, S., Canbas, A., Cabaroglu, T., Erten, H & Gunata, Z (2006) Aroma components of cv Muscat of Bornova wines and influences of skin contact treatment Food Chemistry, 94, 319–326 Singleton, V (1995) Maturation of wines and spirits: comparisons, facts, and hypotheses American Journal of Enology and Viticulture, 46, 98–115 Ó 2010 The Authors International Journal of Food Science and Technology Ó 2010 Institute of Food Science and Technology International Journal of Food Science and Technology 2010 2431 2432 Odorant compounds in Oloroso sherry wines L Zea et al Tulyathan, V., Boulton, R.B & Singleton, V.L (1989) Oxygen uptake by gallic acid as a model for similar reactions in wines Journal of Agricultural and Food Chemistry, 37, 844–849 Vilanova, M & Sieiro, C (2006) Determination of free and bound terpene compounds in Albarin˜o wine Journal of Food Composition and Analysis, 19, 694–697 International Journal of Food Science and Technology 2010 Zea, L., Moyano, L., Moreno, J & Medina, M (2007) Aroma series as fingerprints for biological ageing in fino sherry-type wines Journal of the Science of Food and Agriculture, 87, 2319–2326 Zea, L., Moyano, L & Medina, M (2008) Odorant active compounds in Amontillado wines obtained by combination of two consecutive ageing processes European Food Research and Technology, 227, 1687–1692 Ó 2010 The Authors International Journal of Food Science and Technology Ó 2010 Institute of Food Science and Technology International Journal of Food Science and Technology 2010, 45, 2433–2439 Original article Physicochemical and functional properties of full-fat and defatted Moringa oleifera kernel flour Babatunde S Ogunsina,1* Cheruppanpullil Radha2 & Raichur S Govardhan Singh2 United Nations University, Advanced Centre for Food Science and Technology, Mysore 570 020, India Department of Protein Chemistry and Technology, Central Food Technological Research Institute (Council of Scientific and Industrial Research), Mysore 570 020, India (Received 30 March 2010; Accepted in revised form August 2010) Summary Full-fat and defatted Moringa oleifera kernel flours were analysed for their functional properties The effect of pH and NaCl concentrations on the functional properties of the flours was investigated following standard procedures The protein content of full-fat and defatted flour was 36.18 and 62.76 g ⁄ 100 g, respectively The concentrations of other proximate constituents of the defatted flour were higher than those of the full-fat flour Nitrogen solubility was lowest at pH of 4.0 and 9.0, respectively, with maximum solubility occurring at pH of 6.0 Defatting increased the water absorption and fat absorption capacities of Moringa oleifera kernel flour The foaming capacity and foam stability of the defatted flour were 86.0% and 82.0 mL, whereas that of full-fat flour were 20.6% and 18.5 mL respectively The defatted flour showed better emulsification (97.2 mL g)1) than full-fat flour (66.0 mL g)1) The least gelation concentration of the defatted and full-fat flours was 14% and 16% (w ⁄ v) respectively Moringa oleifera kernel flour can be a valuable source of vegetable protein in fortified food products formulation Keywords Flour, functional properties, Moringa oleifera kernel, vegetable protein Introduction As the world food situation worsens daily, occasioned by high population, poverty and malnutrition, animal protein foods (milk, fish, meat, egg, and sea foods) and other vital human dietary needs are unaffordable by low income groups (Kinsella, 1976) Soybean and cowpea, which are popular sources of vegetable protein, have now become cash crops, and emphasis has shifted to other nonconventional legumes and oilseeds such as pigeon pea, winged bean, mucuna bean, madhuca and jack bean (Oshodi & Ekperigia, 1989; Okezie & Bello, 1988) Moringa oleifera, hereafter simply referred to as moringa, is an important traditional vegetable tree in India and some other parts of the tropics; the leaves, flowers and tender immature pods are widely eaten as vegetable curries (Foidl et al., 2001; The Wealth of India, 1985) In some places, the roasted kernels are eaten like peanuts, but the most reported use of the powdered or defatted meal is as a natural flocculent for water purification (Katayon et al., 2006; Foidl et al., *Correspondent: Tel: +234-805-9881048; e-mail: bsogunsina@yahoo.com 2001; Al-Kahtani & Abou-Arab, 1993) Several previous studies on moringa leaves found that it is substantially rich in iron and beta-carotene and a proven antidote for malnutrition in infants and nursing mothers (Ramachandran et al., 1980) The high protein content of the moringa kernel and its good balance of essential amino acids (Foidl et al., 2001; Gopalan et al., 2007; The Wealth of India, 1985) suggest that it can supplement cereal and tuber flours, which are not only low in protein but deficient in essential amino acids; however, there is little information on its functional properties and possible food applications Vegetable proteins in the form of defatted, detoxified or debittered flours, concentrates, isolates and hydrolysates are desirable in various food products (Kinsella, 1976) Their utilisation and consumer acceptance in food systems largely depend on their functional properties that involve their capacity to go into solution and their behaviour at air ⁄ water and oil ⁄ water interface in food systems (Adebowale & Lawal, 2004; Padilla et al., 1996) This work therefore focuses on the functional properties of full-fat and defatted Moringa oleifera kernel flours with the view to providing valuable information regarding their possible utilisation in various food applications doi:10.1111/j.1365-2621.2010.02423.x Ó 2010 The Authors International Journal of Food Science and Technology Ó 2010 Institute of Food Science and Technology 2433 2434 Physicochemical and functional properties of moringa kernels flour B S Ogunsina et al Materials and methods Source of material and samples preparation Ten kg of matured and dry Moringa oleifera seeds was purchased randomly from local market The seeds were dehulled using an attrition plate mill (Model A-453, Chandra Manufacturing Co., Chennai, India), and the hulls were separated using an aspirator Foreign matters and immature or defective kernels were removed from the lot, and it was then kept in airtight containers under refrigeration until when needed About kg of the kernels was milled in a Quadrumat mill (Brabender, Duisburg, Germany) to obtain full-fat moringa kernels flour (FFMF), which passed through 100 -lm mesh Preliminary experiment indicated that the optimum moisture content (MC) for flaking moringa kernels is 8.5% (w.b.); hence, about 3.5 kg of the kernels was conditioned from an initial MC of 5.46 to 8.5 g of H2O ⁄ 100 g (w.b.) and flaked at a drum clearance of 0.85 mm using a flaking machine (Model J #6725; Kvarnmaskiner Malmo, Sweden) The flakes were dried at 50–55 °C for h to 5.5 g of H2O ⁄ 100 g MC (w.b.) and subsequently defatted by repeated washing with hexane until the fat content was below 1% The defatted sample was air dried at room temperature (30 °C) for about 24 h (Arogundade et al., 2004) to remove residual solvent and milled to pass through a 100- lm mesh stainless steel sieve This was designated as defatted moringa kernels flour (DMSF) The two flour samples (i.e FFMF and DMSF) were stored in airtight containers Experimental procedure Proximate analysis The proximate composition of the flour samples was determined following standard method (AOAC, 2000) Moisture content of the sample was determined by oven drying About 20 g of FFMF was extracted in petroleum ether (b.p 40–60 °C) under reflux for h using a soxhlet unit The extract was desolventised in a flash evaporator (Rotavac Heidolph Laborota 4002, Heidolph Instruments GmbH & Co KG, Schwabach, Germany) to obtain crude fat content, the percentage of which was determined by gravimetry Total nitrogen content was estimated using the Kjeldahl procedure, and crude protein was obtained with multiplying the nitrogen content by 6.25 Energy content was calculated using Atwater factors in which energy in kcal ⁄ 100 g ofsample = · fat + · protein + · carbohydrate (Alobo et al., 2009) Determinations were carried out in triplicates Determination of functional properties Water and fat absorption capacities were determined following the procedure of Beuchat (1977) Approx- International Journal of Food Science and Technology 2010 imately g of the sample was mixed with 10 mL of distilled water (or refined groundnut oil for fat absorption capacities) in a 15 mL centrifuge tube at 27.5 °C for 30 The mixture was centrifuged at 5000 · g for 30 min, and the supernatant was quantified using a 10 mL graduated cylinder Water and fat absorption capacities were expressed as grams of water or oil bound per 100 g of flour, taking the density of water and that of groundnut oil as and 0.9 g mL)1, respectively The bulk density of the flour samples was determined following the method of Alobo et al (2009) About 25 g of flour sample was placed in a 50 mL graduated cylinder, and the loose bulk density was calculated as a ratio of the weight of sample to the loose volume The cylinder was tapped gently on a laboratory table top several times (up to eighty tappings) until there was no further diminution of the flour Tap bulk density was calculated as a ratio of the weight of sample to the tap volume The values reported were averages of five determinations Hausner ratio of the flour samples was calculated as a ratio of tap density to loose density Nitrogen solubility of the sample was determined using the method of Chobert et al (1988) considering pH ranging from 2.0 to 10.0 Samples were dispersed in distilled water (1% w ⁄ v) and mixed thoroughly at 27.5 °C for using a magnetic stirrer The pH of the solution was adjusted with 0.1 m HCl or 0.1 m NaOH using a controlled dynamics pH meter (CD Instruments, Bangalore, India) After 45 of stirring, the pH was measured (or readjusted if necessary), and the samples were centrifuged at 10 000 · g for 30 The supernatant was filtered to obtain a clear solution The nitrogen content in the supernatant was determined by Kjeldahl method (AOAC, 2000) Triplicate determinations were carried out, and solubility profile was obtained by plotting average values of nitrogen solubility (%) against pH Nitrogen solubility was calculated as follows: Nitrogen solubility (% ) Nitrogen content in the supernatant  100 ¼ Total nitrogen content in the sample ð1Þ Foaming capacity and stability of the flour samples were determined according to Booma & Prakash (1990) A 2% aqueous dispersion of the sample was mixed thoroughly in a kitchen blender for The content was immediately transferred into a 250 mL graduated cylinder, and the foam volume noted Foaming capacity was calculated as percentage increase in foam volume of the dispersion upon mixing, while foaming stability was estimated as the relative volume of foam left after 30 Foaming capacity (%) Vol after whipping - Vol before whipping 100 2ị ẳ Vol before whipping ể 2010 The Authors International Journal of Food Science and Technology Ó 2010 Institute of Food Science and Technology Physicochemical and functional properties of moringa kernels flour B S Ogunsina et al Emulsion capacity was determined according to the method of Pearce & Kinsella (1978) About g flour sample was dispersed in 50 mL distilled water (and different concentrations of NaCl ranging from 0.02– 0.5 m) and homogenised in a kitchen blender at high speed to disperse the proteins thoroughly As the dispersion was being homogenised, refined groundnut oil was added at about 0.5 mL s)1 from a burette As the process continued, oil addition was interrupted after each addition of 5–10 mL to prevent sudden rise in temperature until the emulsion became thick and attained maximum viscosity The rate of oil addition was reduced to 2–3 drops until the emulsion reached breakpoint, at which oil and water separated into two phases Emulsion capacity was measured as mL of oil emulsified and held per gram of flour Determinations were carried out at room temperature, and reported values were means of triplicates The minimum gelation concentration was determined following the procedure of Alobo (2004) Sample suspensions of 2%, 4%, 6%, 8%, 10%, 12%, 14%, 16% and 30% (w ⁄ v) were prepared in distilled water The suspensions were heated inside a boiling water bath for h and afterwards subjected to rapid cooling in a cold water bath and further cooling at ± °C for h The minimum gelation concentration was taken as the concentration in which the test tube content did not fall or slip when inverted comparable to that of beniseed, groundnut, mustard and linseed (Yusuf et al., 2008; Gopalan et al., 2007) moringa kernels flour like soybean may be of valuable use as protein enrichment in food products development However, the presence of antinutritional components such as trypsin inhibitors, phytate, tannins, saponins and oxalates in moringa kernels which were reported by Foidl et al (2001) and Makkar & Becker (1997) are subjects for further investigation regarding its suitability and utilisation as human food Functional properties The functional properties of FFMF and DMSF are summarised in Table A significant increase (P < 0.05) was observed in the water and fat absorption of DMSF above that of FFMF because of defatting Similar results had been obtained for full-fat and defatted flours of beniseed, soybean, fluted pumpkin and cashew nuts (Egbekun & Ehieze, 1997; Radha, 2006; Fagbemi & Oshodi, 1991; Alobo et al., 2009) The water absorption capacity of FFMF in this study compares favourably with 130 g ⁄ 100g for full-fat soy flour (Oshodi & Ekperigia, 1989); however for DMSF, it Table Proximate composition of full-fat and defatted moringa kernel flours Composition (g ⁄ 100 g) Statistical analysis Data were presented as means of three determinations ± SD Statistical analyses were performed with SAS (2002) Data were subjected to analysis of variance, and means were separated using Duncan multiple range tests Protein Ash Fat Carbohydrate Energy (kCal ⁄ 100 g) Full-fat flour 36.18 3.73 43.58 16.51 747.70 ± ± ± ± ± Defatted flour b 0.04 0.04b 0.08a 0.07b 0.22a 62.76 6.75 0.08 30.42 373.44 ± ± ± ± ± 0.16a 0.03a 0.0015b 0.05a 0.13b Values are means of triplicates ± SD Means with different letters on same row are significantly different Results and discussion Proximate composition The proximate composition of the FFMF and DMSF is presented in Table As result of defatting, the protein content of the flour increased significantly (P < 0.05) from 36.18 to 62.76 g ⁄ 100 g The defatted flour exhibited increases in carbohydrate and ash contents Earlier reports by Egbekun & Ehieze (1997) and Alobo et al (2009) have showed similar changes in soybeans, beniseed and cashew nut The results showed that the energy value of the full-fat flour was higher than that of the defatted flour; this is because the fat content of a food material contribute more to its energy per unit weight than protein and carbohydrate contents The protein content of moringa kernel flour is comparable to that of soybean and sponge gourd seeds With 39.4 g ⁄ 100 g of sample, the crude fat content of moringa kernels is Table Functional and physical properties of full-fat and defatted moringa kernel flours Property Full-fat flour Defatted flour Water absorption capacity (g of H2O per 100 g of sample) Fat absorption capacity (g of oil ⁄ 100 g of sample) Foaming capacity (%) Foaming stability (mL) Emulsion capacity (mL of oil ⁄ g of sample) Loose bulk density (g cm)3) Tap bulk density (g cm)3) Hausner ratio 115.7 ± 0.2b 130.5 ± 1.0a 129.8 ± 0.3b 208.0 ± 2.6a 20.6 ± 0.4b 18.5 ± 0.1b 66.0 ± 1.0b 86.0 ± 1.0a 82.2 ± 0.4a 97.2 ± 1.6a 0.37 ± 0.01a 0.59 ± 0.01a 1.6a 0.26 ± 0.004b 0.38 ± 0.01b 1.5b All values are means of triplicates ± SD a, b Means with same letters on same row are significantly different Ó 2010 The Authors International Journal of Food Science and Technology Ó 2010 Institute of Food Science and Technology International Journal of Food Science and Technology 2010 2435 Physicochemical and functional properties of moringa kernels flour B S Ogunsina et al International Journal of Food Science and Technology 2010 pH of 6.0 for the two flour samples The flour showed increasing and decreasing trends as pH varied from acidic to alkaline, reaching a peak at pH 6.0 and decreased similarly afterwards up to pH 9.0 Between pH 9.0 and 10.0, an increase in the nitrogen solubility was observed The foaming capacity and foaming stability of FFMF and DMSF at different pH are shown in Figs and It 140 120 Nitrogen solubility (%) is less than the values reported for soy flour and cashew kernels (Narayana & Narasinga Rao, 1982 and Alobo et al., 2009) The fat absorption capacity of FFMF increased upon defatting and compares favourably with defatted soybean and cashew kernels flours (Yusuf et al., 2008; Alobo et al., 2009) Kinsella (1976) earlier established that hydrophobic proteins have superior ability in binding of lipids Water ⁄ fat-binding capacity of proteins is an index of its ability to absorb and retain water ⁄ oil, which in turn influences their behaviour in food products This is an important parameter for flours intended for baked or aqueous foods where hydration and shortening is desirable While water absorption capacity is considered critical for proteins intended for use in viscous foods like soups, gravies, dough and baked products, fat absorption capacity determines the texture and mouth feel of the protein material of the flour will give desirable in extenders, comminuted meats and baked foods (Igene et al., 2005) With the good potentials shown by its properties, moringa kernel flours may replace some legumes and oilseeds as thickeners used in some liquid and semi-liquid foods In Table 2, it was observed that the loose and tap bulk densities of FFMF were significantly higher (P < 0.05) than that of DMSF This may be attributed to the reduction in the weight per unit volume of the flour particles upon defatting The bulk density of DFMF was less than that of cashew nut (Alobo et al., 2009); soybean (Padilla et al., 1996) and beniseed (Egbekun & Ehieze, 1997) Bulk density is an important parameter in food products handling, packaging, storage, processing and distribution It is particularly useful in the specification of products derived from size reduction or drying processes (Barbosa-Canovas et al., 2005) For the two flour samples, hausner ratio (HR), which measures the flowability of the flours, was observed to be >1.4 A flour sample with HR > 1.4 will usually not fluidise easily (Barbosa-Canovas et al., 2005) These results indicate that the two flours that were studied have low flowability and can be categorised as difficult flowing flours, and usually, the lower the flowability a flour, the more compressible it becomes The nitrogen solubility profiles of the two flour samples as affected by pH are shown in Fig It was observed that the highest solubility was 52.6% for DMSF and 55% for FFMF Defatting had no noticeable effect on nitrogen solubility For both flours, minimum solubility occurred around pH 4.0 and 9.0; (i.e 27.82 and 29.2% for FFMF and DMSF respectively) showing two isoelectric points This behaviour is quite different from that of some other seed flours (e.g soybean, beniseed and cashew nut) that have one isoelectric point (Radha, 2006; Yusuf et al., 2008; Alobo et al., 2009) This trend suggests that for moringa kernel flours, soluble proteins are recoverable at both acidic and alkaline pH Maximum solubility was observed at 100 DMSF FFMF 80 60 40 20 pH 10 Figure Nitrogen solubility profile of the moringa kernel flour in water as a function of pH ranging from 2.0 to 10.0 (h) Defatted moringa kernels flour ( ) Full-fat moringa kernels flour 140 120 Foaming capacity (mL) 2436 DMSF 100 FFMF 80 60 40 20 10 pH Figure Foaming capacity as a function of pH Foam was produced by whipping 2% aqueous dispersion of the protein sample in a kitchen blender for at 27 °C (h) Defatted moringa kernels flour ( ) Full-fat moringa kernels flour Ó 2010 The Authors International Journal of Food Science and Technology Ó 2010 Institute of Food Science and Technology Physicochemical and functional properties of moringa kernels flour B S Ogunsina et al Table Gelation properties of full-fat and defatted moringa kernel 140 flours Foam stability (mL) 120 Flour concentration (% w ⁄ v) DMSF FFMF 100 Flour sample 10 12 14 16 30 80 DMSF FFMF ) ) ) ) ) ) ± ) ± ) ± ± + ± + + + + 60 ), Not gelled; ±, slightly gelled but slipped; +, gelled 40 20 10 pH Figure Foam stability as a function of pH Foam was produced by whipping 2% aqueous dispersion of the protein sample in a kitchen blender for at 27 °C (h) Defatted moringa kernels flour ( ) Full-fat moringa kernels flour 140 Emulsion capacity (mL g—1) DMSF 120 FFMF 100 80 60 40 20 0 0.02 0.05 0.1 0.2 0.3 0.4 0.5 NaCl concentration (M) Figure Emulsion capacity as a function of NaCl concentration Emulsion was produced by homogenising 2% protein sample in a kitchen blender with continuous addition of oil at a flow rate of 0.5 mL s)1 (h) Defatted moringa kernels flour ( ) Full-fat moringa kernels flour was observed that the FC and FS of DMSF was far greater than that of the FFMF at almost all pH As the pH varied from 2.0 to 10.0, the foaming capacities of FFMF decreased from 26% to 14% attaining a peak of 28% at pH 6.0, whereas for DMSF, it increased from 56% to 98% with a peak occurring at pH 8.0 (Fig 2) For both flour samples, it was observed that foaming capacity reduced after pH 8.0 Foaming stability of DMSF increased with slight fluctuations as pH increased from 2.0 to 10.0 Peak values of 84 and 112 mL were observed at pH 4.0 and 8.0, respectively, whereas for FFMF, a consistent decrease in foaming stability was observed Akintayo et al (1998) linked high foaming capacity to the flexible protein molecules that reduce surface tension, while low foaming capacity is because of highly ordered globular proteins, which are relatively difficult to denature The good foaming properties of DMSF suggest its usefulness as aerating agent in food systems, where high foaming capacity and stability are required e.g whipped toppings and ice-cream mixes Figure shows the emulsion capacity of the flour samples at different concentrations of NaCl ranging from 0.02–1 m The emulsion capacity of the FFMF and DMSF flours was observed to be 66 and 97.2 mL g)1 Maximum values were 114 for DMSF and 76 mL g)1 for FFMF at 0.05 m of NaCl concentration For DMSF, the peak was maintained at 0.1 m concentration of NaCl after which a decrease was observed The lowest values of emulsion capacity were 81 mL g)1 for DMSF at 0.3 m and 55 mL g)1 for FFMF at 0.5 m Sathe et al (1982) had earlier reported that the emulsion capacity of winged bean protein increased as the concentration of protein in solution decreased Concentration-dependent emulsifying activity has been explained based on adsorption kinetics (Phillips, 1981) When protein concentration is low, the rate of adsorption is diffusion controlled, but at high protein concentration, there is an activation barrier to adsorption (Adebowale & Lawal, 2004) Under the later conditions, the ability of the protein molecule to create space in the existing film and to penetrate and rearrange on the surface reduces The minimum gel concentration (w ⁄ v) of DMSF and FFMF was 14% and 16% (w ⁄ v) respectively (Table 3) The DMSF was observed to gel slightly and showed evidence of slipping at 8% concentration, whereas for FFMF, a similar behaviour was exhibited at a concentration of 12% Minimum gelation concentration (w ⁄ v) of 14% had been reported earlier for Caryodendron orinocense (Padilla et al., 1996), lupine seed (Sathe et al., 1982) and Adenopus breviflorus (Oshodi, 1992), but this is higher than 10% for soybean flour (Padilla et al., 1996) The ability of proteins to form gels varies for Ó 2010 The Authors International Journal of Food Science and Technology Ó 2010 Institute of Food Science and Technology International Journal of Food Science and Technology 2010 2437 2438 Physicochemical and functional properties of moringa kernels flour B S Ogunsina et al different legume and oil seed flours (Moure et al., 2006) Sathe et al (1982) suggested that this variation depends on the relative ratios of different constituent proteins, carbohydrates and lipids, and the interactions between such components may affect functional properties Narayana & Narasinga Rao (1982) also linked gelation to structured aggregation of denatured molecules that increases with protein and starch concentration; as the proteins undergo dissociation by heat, carbohydrates are gelatinised and crude fibre becomes swollen (Mulvihihill & Kinsella, 1987; Alobo et al., 2009) This provides the required structural matrix for holding water, flavours, sugars and food ingredients and enhances the functionality of flours in food products Conclusion The results of this study show that the proximate composition and functional properties of moringa kernel flour were affected by defatting The defatted flour had higher protein solubility, water and fat absorption than the full-fat flour The foaming and emulsion properties of the flour improved, following defatting In view of the assessed functional properties, moringa kernel flour may be suggested as a good source of vegetable protein in model food systems that could be explored especially in the developing countries where malnutrition is prevalent Acknowledgments The fellowship of the United Nations University, Tokyo, Japan and Central Food Technological Research Institute (CFTRI), Mysore, India, where this research was undertaken are gratefully acknowledged Many thanks to The Director, CFTRI, Dr V Prakash; The Head of PCT Department, Dr A.G Appu Rao and Ms T.N Indira for their selfless commitment to the success of this aspect of the work References Adebowale, K.O & Lawal, O.S (2004) Comparative study of the functional properties of bambara groundnut (Voandzeia subterranean), jack bean (Canavalia ensiformis) and mucuna bean (Mucuna pruriens) flours Food Research International, 37, 355–365 Akintayo, E.T., Oshodi, A.A & Esuoso, K.O (1998) Effects of NaCl, ionic strength and pH on the foaming and gelation of pigeon pea (Cajanus cajan) protein concentrates Food Chemistry, 64, 1–6 Al-Kahtani, H.A & Abou-Arab, A.A (1993) Comparison of physical, chemical, and functional properties of Moringa peregrina (AlYassar or Aoă-Ban) and soybean proteins Cereal Chemistry, 70, 619–626 Alobo, A.P (2004) Proximate composition and selected functional properties of defatted papaya (Carica papaya L.) kernel flour Plant Foods for Human Nutrition, 58, 1–7 Alobo, A.P., Agbo, B.N & Ilesanmi, S.A (2009) Physicochemical and functional properties of full fat and defatted cashew kernel flours International Journal of Food Science and Technology, 44, 581–585 International Journal of Food Science and Technology 2010 AOAC (2000) Official Methods of Analysis Association of Official Analytical Chemists Vol II 17th Edn (edited by P Cunnif), Pp 1–37 Arlington, VA, USA: AOAC Arogundade, L.A., Akinfenwa, M.O & Salawu, A.A (2004) Effect of NaCl and its partial or complete replacement with KCl on some functional properties of defatted Colocynthis citrullus L seed flour Food Chemistry, 84, 187–193 Barbosa-Canovas, G.V., Ortega-Rivas, E., Juliano, P & Yan, H (2005) Food Powders: Physical Properties, Processing and Functionality Pp 71–74 London: Kluwer Academic Publishers Beuchat, L.B (1977) Functional and electrophoretic characteristics of succinylated peanut flour protein Journal of Agricultural and Food Chemistry, 25, 258–261 Booma, K & Prakash, V (1990) Functional properties of the flour and the major protein fraction from sesame seed, sunflower seed and safflower seed Acta Alimentaria, 19, 163–176 Chobert, J.M., Sitohy, M.Z & Whitaker, J.R (1988) Solubility and emulsifying properties of casein modified enzymatically by Staphylococcus aureus V8 protease Journal of Agricultural and Food Chemistry, 36, 883–892 Egbekun, M.K & Ehieze, M.U (1997) Composition and functional properties of full fat and defatted beniseed (Sesamum indicum L.) flour Plant Foods for Human Nutrition, 51, 35–41 Fagbemi, T.N & Oshodi, A.A (1991) Chemical composition and functional properties of full fat fluted pumpkin seed flour (Telfairia occidentalis) Nigerian Food Journal, 9, 26–32 Foidl, N., Makkar, H.P.S & Bekker, K (2001) The potential of Moringa oleifera for agricultural and industrial uses Moringa Review Tanzania: Dar Es salaam Gopalan, C., Rama Sari, B.V & Balasubramanian, S.C (2007) Nutritive Value of Indian Foods Pp 20–30 Hyderabad: National Institute of Nutrition, Indian Council of Medical Research Igene, F.U., Oboh, S.O & Aletor, V.A (2005) Effects of some processing techniques on the functional properties of winged bean seed flours Journal of Food, Agriculture & Environment, 3, 28–31 Katayon, S., Megat Mohd Noor, M.J., Asma, M et al (2006) Effects of storage conditions of Moringa oleifera seeds on its performance in coagulation Bioresource Technology, 97, 1455–1460 Kinsella, J.E (1976) Functional properties of proteins in foods: a Survey Critical Reviews in Food Science and Nutrition, 7, 219–280 Makkar, H.P.S & Becker, K (1997) Nutrients and antiquality factors in different morphological parts of the Moringa oleifera tree Journal of Agricultural Science, Cambridge (128, 311–322) Cambridge University Press USA Moure, A., Sineiro, J., Dominguez, H & Parajo, J.C (2006) Functionality of oilseed protein products: a Review Food Research International, 39, 945–963 Mulvihihill, D.H & Kinsella, J.E (1987) Gelation characteristics of whey proteins and b-lactoglobulins Food Technology, 41, 102– 111 Narayana, R & Narasinga Rao, M.S (1982) Functional properties of raw and heat processed winged bean (Psophocarpus tetragonolobus) flour Journal of Food Science., 57, 1534–1538 Okezie, O & Bello, A.B (1988) Physico-chemical and functional properties of winged beans flour and isolate compared with soy isolate Journal of Food Science, 53, 450–454 Oshodi, A.A (1992) Proximate composition, nutritionally valuable minerals and functional properties of Adenopus breviflorus Benth seed flour and protein concentrate Food Chemistry, 45, 79–83 Oshodi, A.A & Ekperigia, M.M (1989) Functional properties of pigeon pea Food Chemistry, 34, 1–5 Padilla, F.C., Alvarez, M.T & Alaro, M.J (1996) Functional properties of barinas nut (Caryodendron orinecense Karst., Euphorbiaceae) flour compared to those of soybean Food Chemistry, 57, 191–196 Pearce, K.N & Kinsella, J.E (1978) Emulsifying properties of protein: evaluation of a turbidimetric technique Journal of Agricultural and Food Chemistry, 26, 716–723 Ó 2010 The Authors International Journal of Food Science and Technology Ó 2010 Institute of Food Science and Technology Physicochemical and functional properties of moringa kernels flour B S Ogunsina et al Phillips, M.C (1981) Protein conformation at liquid interfaces and its role in stabilizing emulsions and foams Journal of Food Technology, 35, 50 Radha, C (2006) Enzymatic and physical modifications for preparing soy flour for better functional properties PhD Thesis India: Department of Protein Chemistry and Technology Central Food Technology Research Institute, University of Mysore Ramachandran, C., Peter, K.V & Gopalakrishnan, P.K (1980) Drumstick (Moringa oleifera): a multipurpose Indian vegetable Economic Botany., 34, 276–283 SAS (2002) Statistical Analytical Software Guide for Personal Computers.Release 9.1 Cary NC 27513, USA: SAS Institute Inc Sathe, S.K., Deshpande, S.S & Salunkhe, D.K (1982) Functional properties of winged bean (Psophocarpus tetragonolobus) protein Journal Food Science, 47, 503–509 The Wealth of India (1985) A Dictionary of Indian Raw Materials and Industrial Products, Vol VI, (Council of Scientific and Industrial Research, New Delhi), 425–429 Yusuf, A.A., Ayedun, H & Sanni, L.O (2008) Chemical composition and functional properties of raw and roasted Nigerian benniseed (Sesamum indicum) and bambara groundnut (Vigna subterranean) Food Chemistry, 111, 277–282 Ó 2010 The Authors International Journal of Food Science and Technology Ó 2010 Institute of Food Science and Technology International Journal of Food Science and Technology 2010 2439 International Journal of Food Science and Technology 2010, 45, 2440 2440 Book review Stored-Product Insect Resource By D W Hagstrum, B Subramanyam USA: AACC International Inc., 2009 Hard cover, 509 pp ISBN: 978-1-891127-66-3 Price: $175 [http://www.apae.uth.gr/_en/CV_en/CV_Stamopoulos_en pdf] Stored-product Insect Resource is a broad-ranging survey and an extensive database of insect species associated with stored commodities during storage, transportation, processing and marketing It is the result of an extensive compilation of about 2200 relative scientific articles summarising about 11.000 records of insect association with stored products worldwide The book encloses three major sections organised into 11 chapters The first section (chapters 1–7 and 11) provides alphabetical lists of stored-product insect species, their synonyms, their distribution worldwide, literature and websites at which pictures can be found, identification and biology sources, and commodities and facilities they can be found The different lists are compiled by genus (Ch.1), by families (Ch 2), by keys (Ch 3), by commodities that insect species are reported to be associated with (Ch and 7), by their damage potential (Ch 5), by their common names (Ch 6) and by the generic names of insect species (Ch 11) The second section (Ch and 10) provides a huge and extensive relative literature and an overview of additional books and review articles on stored-product insects Finally, the third section (Ch 9) discusses the methods of collecting and preserving insects for identification purposes My only reservation in such type of works is the potential sources of error that any compilation could embody because host records in the literature are frequently ambiguous and at the root lies misidentification of either host plant or pest by the original observer or recorder Furthermore, a circumstantial presence of a species in a commodity or an ‘artificial’ plant attack in laboratory experiments, does not presuppose an insect– plant relationship In such cases, erroneous host plant records are frequently reproduced by different authors, and so they end by representing false scientific data Such typical example is the family of Bruchidae where erroneous host records are very common (see e.g Acanthoscelides obtectus as a pest of Lentis esculenta and Vicia faba or Bruchus rufimanus as pest of Phaseolus vulgaris) Nevertheless, Stored-product Insect Resource is undoubtedly a welcome addition to the literature on stored-product pests, particularly for stored-product entomologists or technicians as well as for urban entomologists It will also appeal to the food industry which is deeply concerned about the impact of storedproduct insects on food quality and food safety As a researcher, I find this book very interesting and helpful Prof D C Stamopoulos Department of Agriculture, Ichthyology & Aquatic Environment, School of Agricultural Sciences, University of Thessaly, 38446 Volos, Greece doi:10.1111/j.1365-2621.2010.02329.x Ó 2010 The Author International Journal of Food Science and Technology Ó 2010 Institute of Food Science and Technology ... health: fermentation and short-chain fatty acids Journal of Clinical Gastroenterology, 40, 235–243 Supporting Information Additional Supporting Information may be found in the online version of this... (Table 1) There was an increase in bulk density with frying time, indicating an increase in mass per unit volume of coating sample as a result of fat intrusion during frying Kassama & Ngadi (2005b)... although minerals are lost in the soaking water, soaking and discarding the soaking water increases the bioavailability of the minerals that remained in the beans This is probably caused by a reduction