Dietary fiber
LW T - Food Science and Technology 64 (2015) 446e451 Contents lists available at ScienceDirect LWT - Food Science and Technology j o u r n a l h om e p a g e : w w w e l s e v i e r c o m / l o c a t e / l w t Dietary fiber, mineral elements profile and macronutrients composition in different edible parts of Opuntia microdasys (Lehm.) Pfeiff and Opuntia macrorhiza (Engelm.) Hassiba Chahdoura a, b, Patricia Morales c, Joa~o C.M Barreira a, **, Lillian Barros a , Virginia Ferna ndez-Ruiz c, Isabel C.F.R Ferreira a, *, Lotfi Achour b a Mountain Research Centre (CIMO), ESA, Polytechnic Institute of Bragança, Campus de Santa Apolo nia, Ap 1172, 5301-855 Bragança, Portugal Laboratoire de Recherche “Bioressources: Biologie Int egrative & Valorisation”, Institut Sup erieur de Biotechnologie de Monastir, Universit e de Monastir, Avenue Tahar Hadded, BP 74, 5000, Monastir, Tunisia c Departamento de Nutricio n y Bromatología II, Facultad de Farmacia, Universidad Complutense de Madrid (UCM), Plaza Ramo n y Cajal, s/n, E-28040 Madrid, Spain b a r t i c l e i n f o Article history: Received 10 January 2015 Received in revised form 25 April 2015 Accepted May 2015 Available online 18 May 2015 Keywords: Opuntia spp Cladodes Dietary fiber Micro- and macro-elements a b s t r a c t In this era of functional foods, people constantly seek for new healthier food products with suitable ratios of bioactive components such as fiber and/or mineral elements The genus Opuntia, commonly known as cactus, has the required characteristics to be considered as a functional food Opuntia microdasys (Lehm.) Pfeiff and Opuntia macrorhiza (Engelm.), were previously studied for their phytochemical profiles and antioxidant activity, demonstrating their potential applications Each botanical part showed distinct characteristics, allowing its use for different purposes Bearing this in mind, this follow-up work was designed to acquire an irreproachable knowledge on the morphological characters, nutritional compo- sition, fiber and mineral elements profiles of the cladodes, pulp and seeds Most of the parameters were also studied in the juice Seeds gave the highest contents in micro (Fe: 37e94; Cu: 392e992; Mn: 64 e158; Zn: 143e237, in mg/100 g fw) and macroelements (Ca: 76e89; Mg: 5.1e7.3; Na: 8e13; K: 63e176, in mg/100 g fw), nutritional compounds (fat: 6.5e8.5; protein: 2.3e2.9; carbohydrates: 61, in g/100 g fw) and fibers (IDF: 39e40; SDF: 15e26, in g/100 g fw) The acquired knowledge is essential to define suitable dietary guidelines, strengthening Opuntia spp as a potential functional food © 2015 Elsevier Ltd All rights reserved Introduction Nowadays, consumers are highly concerned in following a healthy diet with low caloric value, low levels of cholesterol and saturated fats, preferring the so called functional foods, due to their potential positive effects on health Among the top priorities, consumers seek food products with high dietary fiber content, since a daily intake of 25 g of fiber is recommended in order to prevent different pathologies, namely constipation, colon cancer, cardiovascular disease and obesity, among others (Ayadi, Abdelmaksoud, Ennouri, & Attia, 2009; Kim et al., 2012; Ternent et al., 2007) The mineral content of any food commodity is also * Corresponding author Tel.: þ351 273303219; fax: þ351 273325405 ** Corresponding author Tel.: þ351 273303309; fax: þ351 273325405 E-mail addresses: jbarreira@ipb.pt (J.C.M Barreira), iferreira@ipb.pt (I.C.F.R Ferreira) http://dx.doi.org/10.1016/j.lwt.2 015.05.011 0023-6438/© 2015 Elsevier Ltd All rights reserved of high importance, since mineral elements (at suitable levels) play a vital role in human health: acid-base balance maintenance; osmotic regulation of fluid and oxygen transport in the body; catalytic processes within enzymatic activities associated with metabolic, endocrine and immune systems; bones growth and formation (McDowell, 2003; Nabrzyski, 2007; Soetan, Olaiya, & Oyewole, 2010) Cactus (Opuntia spp.) is considered to have originated in tropical America, but it has been introduced to other regions of the world, such as Europe (particularly the Mediterranean countries) and Af- rica More than 1500 species of cactus (Cactaceae family) belong to the Opuntia genus and many produce edible and highly flavored berry type fruits These fruits consist of a thick pericarp (peel) with a number of glochids of small prickles, reddish purple, yellow or white in color, with a luscious sweet pulp intermixed with a number of small seeds (Abdel-Hameed, Nagaty, Salman, & Bazaid, 2014; Felker et al., 2005) This genus presents modified stems, 22 H Chahdoura H Chahdoura et al et /al.LWT / LWT - Food - Food Science Science andand Technology Technology 64 (2015) 64 (2015) 446e451 446e451 22 known as cladodes, which are succulent and articulate organs composed by an outer part (formed by the chlorenchyma, where photosynthesis occurs) and an inner part (formed by a white medullar parenchyma whose main function is water storage) (Kim et al., 2013) The cladodes are usually consumed after a removing the spines, washing, cutting and decoction (Ramírez-Moreno, Co rdoba-Díaz, Sa nchez-Mata, Díez-Marque s, & Gon~ i, 2013) The cladodes are used in many varieties of salad (after being cut in small cubes and immerged in vinegar), as flour quality enhancers (Kim et al., 2012; Ramírez-Moreno, Co rdoba-Díaz, Sanchez-Mata, Díez- Marque s, & Gon~ i, 2015), or consumed as dehydrated foods (Medina-Torres, Gallegos-Infante, Gonzalez-Laredo, & Rocha- Guzman, 2008) Opuntia fruits are used to extract juice and as jam ingredients, as well as to produce a special type of honey, named “the Honey of Tuna” (Mezzour, 2000), but they still have little industrial utilization, being mainly consumed as fresh fruits (Castro-Mun~ oz, Barraga n-Huerta, & Ya n~ezFerna ndez, 2015) Opuntia fruits are also used for the extraction of natural pigments and to prepare an alcoholic beverage named “Colonche” (Touil, Chemkhi, & Zagrouba, 2010) Recent studies indicate also poten- tial utilizations of cactus cladodes and fruits (juices, concentrates and powders) as functional ingredients for the soft drink market (Kim et al., 2013) The scientific community has been focused in the nutritional and health-promoting benefits of Opuntia spp (e.g., Ammar, Ennouri, & Attia, 2015; Chahdoura et al., 2014; Gopi, Kanimozhi, & Kavitha, 2015; Kwon & Song, 2005; Lee, Kim, & Lee, 2004; Park, Lee, & Kang, 2005; Stintzing & Carle, 2005) Furthermore, cactus pear fruit is one of the most representative fruits in some cultures and has recently gained attention for its nutritional value Its high levels of betalains, taurine, dietary fiber, minerals (calcium and magnesium) and antioxidants deserve special attention (Morales, Ramírez-Moreno, Sanchez-Mata, Carvalho, & Ferreira, 2012; Piga, 2004; Prieto-García et al., 2006) In terms of bioactivity, Opuntia spp cladodes and fruits are known for medicinal proper- ties in the treatment of arteriosclerosis (Kwon & Song, 2005; Zhao et al., 2012), diabetes (Lo pez-Romero et al., 2014) or hyperglycemia (Andrade-Cetto & Wiedenfeld, 2011), and also for their antitumoral (Sreekanth, Arunasree, & Roy, 2007) and antileishmanial (Bargougui et al., 2014) activities Herein, different botanical parts (cladodes, pulp and seeds) and the juice of Opuntia microdasys (Lehm.) Pfeiff and Opuntia macro- rhiza (Engelm.) were characterized for their nutritional composi- tion, dietary fiber and mineral elements The botanical parts were also evaluated for their morphological characters The obtained results raise the possibility of using Opuntia spp as sources of functional ingredients in food industry, or consuming these plants as functional foods per se bottom) Fruit skins were removed and the pulp (edible portion) was manually separated from the seeds, which were further subtracted of any mucilaginous material The juice was extracted by mechanical pressure avoiding contact with any metallic surface All botanical parts and the obtained juice were lyophilized (FreeZone 4.5 model 7750031, Labconco, Kansas City, MO, USA) Freeze-dried Material and methods Total mineral content (ashes) and mineral elements analysis were performed on dried samples The method 930.05 (1965) of AOAC was used (Horwitz & Latimer, 2005); 500 mg of each sample were subject to dry-ash mineralization at 550 ± 15 C The residue of incineration was extracted with HCl (37 g/100 g of solution) and HNO3 (50 g/100 g of solution) and made up to an appropriate volume with distilled water, where Fe, Cu, Mn and Zn were directly measured An additional 1/10 (mL/mL) dilution of the sample extracts and standards was performed to avoid interferences between different elements in the atomic absorption spectroscopy: for Ca and Mg analysis in 1.16 g La2O3/100 mL HCl solution (leading to LaCl2); for Na and K analysis in CsCl 2.1 Samples O microdasys (Lehm.) Pfeiff and O macrorhiza (Engelm.) were collected from the Cliff of Monastir (Tunisia) between June and July 2013, according to the phenological cycle of each species (MoussaAyoub, El-Samahy, Rohn, & Kroh, 2011; Pin~ a, Montan~ a, & Man- dujano, 2010) The number of selected terminal fruiting cladodes (9 for each species) and fruits (27 for each species) was defined ac- cording to well established practices (ValdezCepeda, Blanco- Macías, Magallanes-Quintanar, Va zquezAlvarado, & Me ndez-Gal- legos, 2013) All botanical parts were stored under cooling condi- tions (5e7 C) between harvest and sample preparation The cladodes (cut in small portions) and the fruits were washed and manually peeled, after removing of uncolored sides (top and material was further ground and stored at 18 C until analysis 2.2 Morphological properties Cladodes were selected from the uppermost part of the plants ensuring they were 1-year-old All cladodes were cleaned with distilled water, paper-dried to remove washing water and immediately weighted Length and width of each fruit, cladode and seed were measured using a caliper micrometer 2.3 Chemical composition Moisture, protein, fat and ash were determined following the AOAC procedures (AOAC, 1995) The crude protein content (N 6.25) was estimated by the macro-Kjeldahl method; the crude fat was determined using a Soxhlet apparatus by extracting a known weight of sample with petroleum ether; the ash and min- eral content was determined by incineration at 550 ± 15 C Total carbohydrates were calculated by difference Energy was calculated according to the following equation: Energy, kJ/100 g fresh weight (fw) ¼ [4 (gprotein þ gcarbohydrate) þ (gfiber) þ (gfat)] 4.184 2.4 Soluble and insoluble dietary fiber assay AOAC enzymatic-gravimetric methods (993.19 and 991.42) were used for soluble dietary fiber (SDF) and insoluble dietary fiber (IDF) analysis (Horwitz & Latimer, 2005) In brief, freeze-dried samples were treated with alpha-amylase (heat-stable), protease and amyloglucosidase The soluble and insoluble fractions were sepa- rated by vacuum filtration Waste from the digests was dried at 100 C, and protein content was determined in the residue Total fiber is the sum of soluble and insoluble fiber fractions; both were expressed as g/100 g fw sample 2.5 Mineral elements (macro and microelements) (0.2 g/100 g solution) (Ferna ndez-Ruiz, Olives, Ca mara, Sa nchez-Mata, & Torija, 2011; Ruiz-Rodríguez et al., 2011) All measurements were performed in atomic absorption spectroscopy (AAS) with air/acetylene flame in Analyst 200 Perkin Elmer equipment (Perkin Elmer, Waltham, MA, USA), comparing 33 H Chahdoura H Chahdoura et al et /al.LWT / LWT - Food - Food Science Science andand Technology Technology 64 (2015) 64 (2015) 446e451 446e451 absorbance responses with >99.9% purity analytical standard solutions for AAS made with Fe (NO3)3, Cu (NO3)2, Mn (NO3)2, 33 Zn (NO3)2, NaCl, KCl, CaCO3 and Mg band The results were expressed in mg per 100 g of fresh weight 2.6 Statistical analysis For each botanical part, three independent samples were used Each of the samples was taken from pooled cladodes (3 cladodes/ sample), fruits (9 fruits/sample), seeds, juices or pulps Data were expressed as mean ± standard deviation All statistical tests were performed at a 5% significance level using SPSS software, version 22.0 (IBM Corp., USA) For each botanical part and parameter, a t-student test was applied to check for statistically significant differences among species The homogeneity of variance was tested by means of the Levene's test Principal components analysis (PCA) was applied as pattern recognition unsupervised classification method The number of dimensions to keep for data analysis was assessed by the respective eigenvalues (which should be greater than one), by the Cronbach's alpha parameter (that must be positive) and also by the total per- centage of variance (that should be as higher as possible) explained by the number of components selected The number of plotted dimensions was chosen in order to allow meaningful interpretations Results and discussion 3.1 Morphological characteristics O microdasys and O macrorhiza are very distinct plants, despite belonging to the same genus O microdasys is shorter (approxi- mately 60e80 cm tall) and the cladodes present dense areoles, without true spines, presenting also glochids in the center of these “pseudo-spines” In the studied samples, the cladodes dimensions varied around 12 cm long vs cm wide, weighting about 61 g (Table 1) O macrorhiza, on the other hand, is a much larger plant, reaching about 2e5 m high, and the cladodes present long spines (3e8 cm) besides being considerably bigger: around 23 cm long vs 14 cm wide and weighting about 163 g The fruits of both Opuntia also showed noticeable differences, especially concerning the weight (5-fold higher for O macrorhiza) and also regarding its density (data not tabled), since the fruits of O macrorhiza had an approximate volume only 2-fold higher than those of O microdasys Besides these features, the fruit of O microdasys present a deep red- purple colored pulp and thick peel with very small glochids (20e50/fruit), while the fruits of O macrorhiza are red, and have few glochids (about 8/fruit) The seeds of O macrorhiza are as well higher, being also more lignified than O microdasys' seeds All the morphological characters are comparable with those reported in the same species (Anderson, 1999; Haustein, 2004), presenting lower dimensions than those found in Opuntia ficus-indica (ValdezCepeda et al., 2013) In view, of the potential use of Opuntia as a food or feed product, these morphological differences act favoring O macrorhiza (the dimensions were statistically larger and thicker Table Morphological characteristics of fresh cladodes, whole fruits and seeds of Opuntia microdasys (Lehm.) Pfeiff and Opuntia macrorhiza (Engelm.) Sample Species Length (cm) Width (cm) Weight (g) Cladode O microdasys O macrorhiza t-student p-value O microdasys O macrorhiza t-student p-value O microdasys O macrorhiza t-student p-value 12 ± 23 ± 0.001 3.3 ± 0.2 5.0 ± 0.1