A survey of acrylamide levels in foods from the Turkish market

A survey of acrylamide levels in foods from the Turkish market, A survey of acrylamide levels in foods from the Turkish market, A survey of acrylamide levels in foods from the Turkish market

ARTICLE IN PRESS Journal of Food Composition and Analysis 21 (2008) 564– 568 Contents lists available at ScienceDirect Journal of Food Composition and Analysis journal homepage: www.elsevier.com/locate/jfca Original Article A survey of acrylamide levels in foods from the Turkish market ¨ lmez Ã, Fatih Tuncay, Nihat O ¨ zcan, Songu¨n Demirel Huălya O ă BITAK MRC-Food Institute, PO Box 21, Gebze Kocaeli 41470, Turkey TU a r t i c l e in f o a b s t r a c t Article history: Received 28 December 2007 Received in revised form 16 April 2008 Accepted 19 April 2008 This study reports the results of the survey study on acrylamide levels in foods obtained from the Turkish market In addition to the processed foods, traditional Turkish foods especially desserts, were analysed for their acrylamide content A total of 311 samples were analysed for acrylamide content with the GC–MS method including the bromine derivatization Results revealed that the acrylamide content of processed foods shows a great variation between different food groups as well as between brands and within brands No significant change in acrylamide content was observed in foods during months of storage time after their production date & 2008 Elsevier Inc All rights reserved Keywords: Acrylamide GC–MS Food Storage time Introduction Acrylamide is a compound which gained a considerable attention in recent years as it was found to be formed as a result of heat processing in foods Acrylamide is listed as ‘probably carcinogenic to humans’ under the Group 2A by the International Agency for Research on Cancer (IARC) (IARC, 1994) It is now well documented that acrylamide is formed as a result of the reactions of reducing sugars with free amino acids, especially asparagine at high temperatures (Surdyk et al., 2004; Zyzak et al., 2003; Mottram et al., 2002; Stadler et al., 2002; Becalski et al., 2003) Studies revealed that in the daily diet of the Swedes and the Dutch, product groups including potato crisps, French fries, coffee, bread, biscuits and breakfast cereals have a contribution of more than 90% intake of acrylamide (Svensson et al., 2003; Konings et al., 2003) These products are important from the point of view of exposure assessment, either because they contain much higher levels of acrylamide compared to other foods or they are a part of the normal diet for the general population, thus have a high consumption rate The average acrylamide intake through diet was reported to be 0.001 mg acrylamide/kg body weight/day for general population and 0.004 mg/kg body weight/day for high consumers Compared with the BMLD (lower confidence limit for benchmark dose) of 0.30 mg/kg bw/day for the induction of mammary tumours in rats, the margin of exposure (MOE) was calculated to be 300 for general population and 75 for high consumers Since acrylamide is both genotoxic and carcinogenic, the Joint FAO/WHO Expert à Corresponding author Tel.: +90 2626773204; fax: +90 2626412309 ă lmez) E-mail address: Hulya.Olmez@mam.gov.tr (H O 0889-1575/$ - see front matter & 2008 Elsevier Inc All rights reserved doi:10.1016/j.jfca.2008.04.011 Committee on Food Additives considered these MOE values to be low and concluded that it may indicate a human health concern (FAO/WHO, 2005) This study includes data on acrylamide content of the processed foods and the traditional Turkish foods from the Turkish market The variations in acrylamide content of a specific food product depending on the brand and storage time were also highlighted Materials and methods 2.1 Chemicals Acrylamide (+99%, purity) was purchased from Sigma Aldrich (St Louis, MO) Deuterium-labelled acrylamide-d3 was obtained from Cambridge Isotope Laboratory (Andover, MA) The remaining chemicals were purchased from Merck (Darmstadt, Germany) 2.2 Apparatus GC–MS analysis of acrylamide was performed with a PerkinElmer gas chromatography (Perkin-Elmer Autosystem XL, Shelton, USA) coupled to a Perkin-Elmer TurboMass (Perkin-Elmer, Shelton, USA) mass spectrometer equipped with an autosampler The GC column was an HP 50C (30 m  0.25 mm i.e., 0.25 mm film thickness) capillary column from Agilent (USA) 2.3 Sampling A total of 311 samples were analysed for acrylamide content The processed food samples were obtained from local retail stores ARTICLE IN PRESS ă lmez et al / Journal of Food Composition and Analysis 21 (2008) 564–568 H O between the years 2004 and 2006 The traditional foods were purchased from local restaurants They were selected from the foods having a high contribution to the Turkish diet, and expected to contain acrylamide During sampling, for long shelf-life samples (such as biscuits, crisps, flakes, etc.), products in their first–second month of shelf life were selected in order to be able to exclude the effect of storage period (if any) on the level of acrylamide detected, so as to allow the comparison between different brands All the samples were homogenized in a waring commercial blender (Waring Products Division Dynamics Corporation of America, Connecticut, USA) before the analysis For the analysis of foods, five packages from each of three different production dates of the same brand were obtained They were homogenized and 10 g of sub-samples were taken for analysis For most of the the processed foods, at least three most current brands (if available) were selected on the basis of market shares To assess the effect of storage period on acrylamide levels in foods, potato crisps, baby biscuits and wheat flakes were monitored during months after their production date Once the samples were opened, the packages were heatsealed and stored at their normal storage conditions The potato chips were repackaged under nitrogen to be able to simulate the original packaging conditions 2.4 Acrylamide analysis Acrylamide analysis was performed according to the method of Castle et al (1991) Ten grams of homogenized sample was placed into a 250 ml Erlenmeyer flask Twenty microlitres of internal standart (d3-acrylamide, ng/mL in water) was added Then mixed with 50 mL of distilled water at room temperature by stirring for After centrifugation at 2000g for 15 min, the supernatant was decanted through a funnel containing a piece of glass wool into a 250 mL conical flask The solid pellets were resuspended in 25 mL water and recentrifuged For food products with high fat content (crisps, chips, roasted nuts, olive, hazelnut paste, peanut paste, traditional desserts, meals), defatting was performed by using 20 mL of hexane twice at room temperature The combined 565 supernates were treated with 82 mL brominating solution (152 g KBr, mL HBr, 50 mL bromine water and 600 mL water) and allowed to stand for h at 1C After derivatization with bromine, M thiosulphate solution was added to remove the excess bromine until the yellow colour disappeared The solution was transferred into a 250 ml separatory funnel and extracted twice with ethyl acetate The organic phase was centrifuged at 1500g for 15 and the water phase removed with a Pasteur pipette Sodium sulphate anhydrous was used to dry the remaining organic phase The extract was evaporated under a stream of nitrogen gas to about 100 mL at 50 1C Preconditioned Bond-Elut silica gel column with 20% v/v ethyl acetate/hexane was used for clean-up After adding 75 mL of extract, the clean-up column washed with 20% ethyl acetate/hexane (2.5 mL) and 35% ethyl acetate (5 mL) The first mL was discarded and the next mL was collected which was evaporated to a final volume of 50 mL and transferred into a brown autosampler vial Five microlitres of the sample was injected to GC–MS system for the analysis The temperature programme for GC was as follows: held at 50 1C for min, increased to 175 1C at a rate of 10 1C/min and held for min, then increased at a rate of 20 1C/min–270 1C and held for The carrier gas was helium at a constant flow of 0.6 mL/min Analyses were conducted in EI mode by selected ion monitoring of the major ion at m/z 150 and 152 for brominated acrylamide and m/z 153 and 155 for d3-acrylamide 2.5 Quality control The laboratory participated in proficiency tests organized by Food Analysis Performance Assessment Scheme (FAPAS) of the Central Science Laboratory (CSL) York (UK), for breakfast cereal (FAPAS, 2007) and crispbread (FAPAS, 2006), also the second proficiency (2004) test on acrylamide in crispbread, organized by EU Directorate General Joint Research Center Institute for Reference Materials and Measurements (DG JRC IRMM) Moreover, analytical quality control was implemented by the use of certified reference materials (FAPAS 3001-crispbread, 3002-potato crisp, and 3008-coffee) obtained from CSL 14.75 100 m/z 153, 155 (d3-acrylamide) Relative Response (%) m/z 150, 152 (acrylamide) % 15.44 13.25 13.50 13.75 14.00 14.25 14.50 Time (min) 14.75 15.00 Fig GC–MS chromatogram of acrylamide in baby biscuit 15.25 15.50 15.75 ARTICLE IN PRESS 566 ă lmez et al / Journal of Food Composition and Analysis 21 (2008) 564–568 H O 2.6 Statistical analysis Statistical analysis of the data was performed in STATISTICA using non-parametric descriptive statistics and Bow–Whiskers plot procedures ANOVA was applied in order to test the difference in acrylamide levels depending on the brand and storage time Results and discussion 3.1 Acrylamide For acrylamide analysis, the linearity was tested in the range of 120–1200 mg/kg (R2 ¼ 0.999) and the limit of detection (LOD) and the limit of quantification (LOQ) was found to be 10 and 30 mg/kg, respectively The precision of the method was determined by analysing a certified reference material for consecutive days giving a relative standard deviation of 6.6% The recovery of the method calculated for the certified reference material was 107% A sample chromatogram is given in Fig The repeatability relative standard deviation (RSDr) for the validation study for FAPAS T 3001 (crispbread) and T 3002 (potato crisp) were 6.6% (mean ¼ 1305 mg/kg, acceptable tolerance levels ¼ 836–1590 mg/kg) and 4.1% (mean ¼ 168 mg/kg, acceptable tolerance levels ¼ 97–237 mg/kg), respectively The RSDr for the coffee reference material (FAPAS T 3008) obtained from CSL was found to be 18%, with a mean of 240 mg/kg and acceptable tolerance level of 102–247 mg/kg Participation in FAPAS proficiency tests resulted in z-scores of À1.1 and À1.4, respectively, for the breakfast cereal (FAPAS, 2007) (mean ¼ 218 mg/kg, assigned value ¼ 279 mg/kg) and crispbread (FAPAS, 2006) (mean ¼ 925 mg/ kg, assigend value ¼ 1179 mg/kg) samples Participation in the second proficiency test organized by DG JRC IRMM resulted in z-scores of À1.1, 0.9 and 0.2 for three crispbread samples (means 526, 34 and 399 mg/kg, assigned values 497, 46 and 413 mg/kg, respectively) Table shows the mean, median and the ranges for the acrylamide contents of the traditional Turkish foods, and the processed foods of different brands obtained from the Turkish market A total of 311 samples were analysed As the data for the food groups did not show a normal distribution and since the sample size was small, non-parametric statistics were used for the data analysis and the data were plotted using the Box– Whiskers multiple plot procedure (Fig 2) For statistical analysis, values that were lower than the LOD were taken as zero In Fig 2, the medians were demonstrated by the central lines in the box and the ranges by the whiskers As observed in previous survey studies (Koh, 2006; Murkovic, 2004; Konings et al., 2003; Svensson et al., 2003), among all the food groups analysed, the highest level of acrylamide was observed in potato crisps, 2336 mg/kg being the highest value detected Within the group of breakfast cereals, wheat flakes contained the highest level of acrylamide with a median value of 121 mg/kg for the 24 samples analysed Only of the 24 samples were below the LOD Biscuits and crackers were another group of products containing appreciably high levels of acrylamide with median values of 82 and 213 mg/kg, respectively Within the group of nuts, higher levels of acrylamide were detected for roasted almonds and roasted corn A wide variation was observed for the acrylamide content of roasted hazelnuts, which can be attributed to the differences in time–temperature regimes of roasting and also to variety differences of the hazelnuts Among the traditional Turkish foods, desserts cooked by frying or high temperature oven baking, such as baklava and tulumba, contained higher levels of acrylamide (Table 1) The wide variation in the acrylamide content within a specific dessert Table Acrylamide levels in 311 processed and traditional Turkish foods Food group Wheat flakes Oat flakes Rice flake Corn flakes Biscuits Crackers Baby biscuits Infant food (powder) Infant food (canned puree) Bread Toasted bread Crispbread Potato crisps Corn crisps Pidea Bakery (pog˘ac- a) Roasted hazelnut Roasted almond Roasted corn Roasted chickpea (leblebi) Roates peanut Olive (pickled, black) Hazelnut paste Peanut paste Baby food (fresh cheese) Mashed potato powder Instant soups Instant coffee Turkish coffee Hamburger Wafer Chocolate Meat patty Syrup-soaked fried pastries made from unleavened dough lumpb Tulumbac Kadayıfd Kemalpas-a dessertc Tahini (Sesame paste) Molasses (pekmez) Halva Pilaf (boiled rice) Deep-fried vegetabless Fried potato (home-made) Fried potato (fast food rest) Fried potato (frozen potato) Chicken schnitzel Pop corn Omelet Strawberry jam Kakao powder Dried red pepper Mean (mg/kg) Median (mg/kg) 177 34 45 122 198 247 152 19 o10 38 164 95 834 425 o10 120 128 260 194 12 66 82 53 54 o10 o10 50 260 266 o10 180 75 68 193 121 27 68 67 82 213 98 0 43 58 73 818 371 12 19 42 260 195 o10 68 70 35 54 o10 o10 53 254 264 o10 103 78 o10 242 241 o10 512 69 95 93 o10 o10 63 403 74 34 171 o10 o10 o10 o10 50 o10 512 61 42 86 o10 o10 63 414 74 34 171 o10 o10 o10 o10 Range Number of samples o10–468 o10–82 o10–90 35–478 o10–648 26–587 32–613 o10–108 o10–34 o10–85 41–474 o10–226 59–2336 109–835 o10–16 o10–441 o10–421 207–313 100–288 o10–33 o10–120 o10–216 o10–141 45–63 24 16 18 24 22 5 5 4 6 o10–88 95–402 200–336 o10–16 78–486 37–100 o10–203 o10–288 o10–701 o10–23 445–578 o10–145 o10–297 o10–229 60–66 355–436 72–76 5 4 1 1 a A traditional type of slightly leavened, flat pizza-like bread A traditional Turkish dessert composed of finely layered pastry filled with nuts and steeped in syrup c Syrup-soaked fried pastries made from unleavened dough lump d A very fine vermicelli-like pastry baked in syrup and filled with nuts b could be attributed to the level of heat treatment it underwent and the differences in the recipes which is known to play an important role in acrylamide formation A wide variation was also observed for the acrylamide content of molasses, which could be attributed to the production technology, whether it is produced through a traditional open pan boiling process or through evaporation at lower temperatures under pressure Results revealed that the acrylamide content of food groups, such as wheat flakes, biscuits, crackers and potato crisps (Fig 1) also shows a wide variation Differences in processing parameters, ARTICLE IN PRESS ă lmez et al / Journal of Food Composition and Analysis 21 (2008) 564–568 H O 567 2600 2400 2200 2000 Acrylamide (µg/kg) 1800 1600 1400 1200 1000 800 600 400 200 Wheat flakes Oat flakes Rice flakes Corn flakes Biscuits Crackers Baby biscuits Infant foods Bread Crispbread Pide Bakery products Potato crisps Corn crisps Roasted nuts Roasted almond Roasted corn Roasted chickpea (Leblebi) Roasted peanut Hazelnut paste Peanut paste Olive (pickled, black) Mashed potato powder Instant soups Instant coffee Turkish coffee Kakao powder Hamburger Wafers Chocolate Meat patty Chicken schnitzel Baklava Tulumba Kadayif Kemalpaşa dessert Tahini Molasses Halva Pilaf Deep-fried vegetables Fried potato (home-made) Fried potato (fast food) Pop corn Omelet Strawberry jam Dried red pepper Fig Acrylamide levels in food groups analysed with median values, ranges and sample numbers Table Variations in acrylamide content of food samples between different brands and within the same brand Food sample Mean (mg/kg) Median (mg/kg) Range Number of samples Wheat flakes Brand Brand 104a 324b 97 340 65–140 176–468 6 Baby biscuits Brand Brand Brand 232c 96d 287c 211 92 155 98–382 80–119 102–613 5 Values with the same superscript are not significantly different at a level of po0.05 processing methods, type and quality of raw materials, formulations may all account for these variations In order to compare the differences between the same products from different brands, samples of different brands were collected simultaneously from the retail market during years Table depicts the variation of the acrylamide contents between different brands for wheat flakes and baby biscuits For wheat flakes, the data obtained from the samples collected and analysed simultaneously from two different brands showed that Brand contains significantly lower (po0.05) levels of acrylamide compared to its equivalent in Brand For baby biscuits, Brand was found to contain significantly lower (po0.05) levels of acrylamide compared to the other two brands The differences in acrylamide contents between the same product of different brands is worth investigating, as they may give clues on the ways of producing the same product with a lower acrylamide content, if collaborative studies between the industry and the research bodies could be established and the differences in terms of the raw material properties, the processing regimes and the ingredients used in these products can be obtained from the processors clearly This type of data may also provide a guidance for the consumers to choose the brands with lower acrylamide levels Consequently, this may give a push to the industry to decrease the acrylamide levels in their products and may support the as low as reasonably achievable (ALARA) principle to be implemented Table summarizes the effect of storage time on the levels of acrylamide in potato chips, wheat flakes and baby biscuits Unlike Hoenicke and Gatewrmann (2005), the products were stored at their normal storage conditions as recommended on the package As shown in the table, during months of storage after the production date no significant (p40.05) changes in the acrylamide contents of these products were detected ARTICLE IN PRESS ă lmez et al / Journal of Food Composition and Analysis 21 (2008) 564–568 H O 568 Table Effect of storage period on acrylamide levels (mg/kg) in some products Food Second month of shelf life Fourth month of shelf life Sixth month of shelf life Baby biscuits Potato crisps Wheat flakes 153a 432b 456c 144a 437b 463c 151a 446b 446c Values with the same superscript are not significantly different at a level of po0.05 Conclusion A survey of the traditional Turkish foods and the processed foods from the Turkish market was performed for determining the acrylamide contents in these products The traditional Turkish foods and the home-made foods were specifically included in the survey study for acrylamide, so as to use the data in order to evaluate the dietary exposure estimates of the Turkish people The highest level of acrylamide was detected in the potato crisps In general, crisps, biscuits and crackers, coffee, fast food style fried potatoes, roasted nuts and some of the traditional Turkish desserts were among the food products with high levels of acrylamide Significant differences were observed in the acrylamide contents of different brands of the baby biscuits and the wheat flakes No significant change in the acrylamide contents of the baby biscuits, potato crisps and wheat flakes were observed during the months of storage time after their production dates Acknowledgements ă BITAK (The Scientic This study was equally financed by the TU and National Research Council of Turkey) and the European Commission under the FP6 project HEATOX (Contract no FOODCT-2003-506820 Specific Targeted Project) The views expressed in this publication are the sole responsibility of the authors and not necessarily reflect the views of the European Commission Neither the European Commission nor any person acting on behalf of the Commission is responsible for the use which might be made of the information contained herein References Becalski, A., Lau, B.P.Y., Lewis, D., Seaman, S.W., 2003 Acrylamide in foods: occurrence, sources, and modelling Journal of Agricultural and Food Chemistry 51, 802–808 Castle, L., Campos, M., Gilbert, J., 1991 Determination of acrylamide monomer in hyroponically grown tomato fruit by capillary gas-chromatography–massspectrometry Journal of the Science of Food and Agriculture 54, 549–555 FAO/WHO Joint Expert Committee on Food Additives, 2005 Sixty-fourth Meeting Rome, 8–17 February 2005, Summary and Conclusions Available at: /ftp:// ftp.fao.org/es/esn/jecfa/jecfa64_summary.pdfS Hoenicke, K., Gatewrmann, 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Wheat flakes Oat... GC was as follows: held at 50 1C for min, increased to 175 1C at a rate of 10 1C/min and held for min, then increased at a rate of 20 1C/min–270 1C and held for The carrier gas was helium at a. .. (pickled, black) Mashed potato powder Instant soups Instant coffee Turkish coffee Kakao powder Hamburger Wafers Chocolate Meat patty Chicken schnitzel Baklava Tulumba Kadayif Kemalpa? ?a dessert Tahini