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Food Additives & Contaminants: Part B: Surveillance Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/tfab20
Aflatoxin M1 in Tarhana chips a
b
Mustafa Özçam , Ersel Obuz & Halil Tosun
a
a
Department of Food Engineering, Faculty of Engineering, Celal Bayar University, Manisa, Turkey b
Department of Bioengineering, Faculty of Engineering, Celal Bayar University, Manisa, Turkey Accepted author version posted online: 11 Dec 2013.Published online: 20 Feb 2014.
To cite this article: Mustafa Özçam, Ersel Obuz & Halil Tosun (2014) Aflatoxin M1 in Tarhana chips, Food Additives & Contaminants: Part B: Surveillance, 7:3, 182-185, DOI: 10.1080/19393210.2013.874373 To link to this article: http://dx.doi.org/10.1080/19393210.2013.874373
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions
Food Additives & Contaminants: Part B, 2014 Vol. 7, No. 3, 182–185, http://dx.doi.org/10.1080/19393210.2013.874373
Aflatoxin M1 in Tarhana chips Mustafa Özçama*, Ersel Obuzb and Halil Tosuna a
Department of Food Engineering, Faculty of Engineering, Celal Bayar University, Manisa, Turkey; bDepartment of Bioengineering, Faculty of Engineering, Celal Bayar University, Manisa, Turkey
Downloaded by [UQ Library] at 23:45 03 November 2014
(Received 29 October 2013; accepted 8 December 2013) Tarhana chips are a popular traditional fermented food consumed widely in the Kahramanmaraş region of Turkey. Tarhana chips are different from many other types of fermented food in that they are produced in the form of tortilla chips. Cereal and yoghurt are the main ingredients in Tarhana chips. Aflatoxin M1 (AFM1) levels in dairy and dairy-based products are of concern for human health. To investigate AFM1 contamination, a total of 40 samples were collected from Kahramanmaraş region and AFM1 levels were determined by competitive enzyme-linked immunosorbent assay (ELISA). Furthermore, physicochemical characteristics of Tarhana chips were investigated and compared with classic fried chips in terms of nutritional value. Based on data obtained from enzyme-linked immunosorbent assay, 21 (52.5%) out of 40 samples contained AFM1 in the range 0.5–36.6 ng/kg, so AFM1 levels of all samples were below the legal limit. Keywords: Tarhana; chips; Aflatoxin M1; ELISA
Introduction Tarhana is a cereal and yoghurt-based fermented food with a very high consumption rate in Turkey. It is produced by mixing different raw materials such as wheat flour, yoghurt, vegetables, spices and yeast. The next step is fermentation (at 25–30°C during 1–7 days) and drying (Ibanoglu et al. 1999). There are four different types of tarhana, as given by the Turkish Standardization Institute: flour tarhana, semolina tarhana, goce (cracked wheat) tarhana and mixed tarhana (Anonymous 1981). Tarhana production methods differ depending on the region (Daglioglu 2000), but cereals and yoghurt are always the major component (Ibanoglu et al. 1995). There are some other products similar to tarhana in different countries such as kishk in Syria, Jordan and Egypt (Youssef 1990), kushuk in Iraq (Alnouri & Duitschaever 1974), trahana in Greece, atole in Scotland (Tamime et al. 2000) and tahanya/talkuna in Hungary and Finland (Hayta et al. 2002). Tarhana is generally consumed as soup in winter days (Ibanoglu & Ibanoglu 1999). But a different kind of tarhana called Tarhana chips are dried as a thin layer on nugget and usually consumed as tortilla chips instead of soup especially in the Kahramanmaraş region Turkey (Erbas et al. 2005). Obesity has become a major problem in the United States and in many Western countries (Flegal et al. 2002). The major factor causing obesity is high consumption of energy-dense foods, especially snack food (McCrory et al. 1999). Chips account for a high percentage of energy-dense snack foods. Most snack chips are deep fried in hot oil or fat, resulting in products that have a high fat content (Moreira et al. 1999). Consuming large amount of fats *Corresponding author. Email: [email protected] © 2014 Taylor & Francis
and oils, particularly saturated fats, increases coronary heart disease, hypertension, diabetes and cancer risk (Saguy & Dana 2003). In addition, the frying process can release acrylamide, which is classified in Group 2A as a “probable carcinogen to humans” (IARC 2002). It is formed via the Maillard reaction when asparagine and reducing sugars are heated at high temperatures (Stadler et al. 2002; Stadler & Scholz 2004). Potatoes have high amounts of asparagine and reducing sugars. Consequently, fried potato products, such as French fries and chips have been found to contain high levels of acrylamide (Lineback et al. 2012; Medeiros Vinci et al. 2012). However, Western consumers have increasing awareness about a relationship between nutrition, food and health (Saguy & Dana 2001). In recent years, a new diet lifestyle is gaining popularity and consumers have great interest in traditional food products because of their beneficial effect on health (Settanni et al. 2011). Within this framework, Tarhana chips can be considered a healthy alternative instead of classical high-fat fried chips, because Tarhana chips contain cereal and yoghurt, have lower fat and do not contain acrylamide. Yoghurt is one of the two major components of Tarhana chips (Ibanoglu et al. 1995). Hence, Tarhana chips can be recognised as a dairy (yoghurt)-based fermented food. Aflatoxin M1 (AFM1) levels in dairy and dairy-based products are of interest because of human health (Elkak et al. 2012). Yoghurt having low microbiological quality may increase AFM1 levels in Tarhana chips, when it is produced with locally supplied yoghurt which could be contaminated with AFM1. AFM1 is known to be hepatotoxic and carcinogenic, which could
Food Additives & Contaminants: Part B
Downloaded by [UQ Library] at 23:45 03 November 2014
cause mycotoxicosis (Van Egmond 1994). For this reason the European Union (European Commission, 2006) and Turkish Food Codex (Anonymous 2008) set maximum levels for AFM1 in food. Based on Turkish Food Codex, maximum level of AFM1 is 50 ng/kg in potentially risky food (Anonymous 2008). Although there are several studies on total aflatoxin, aflatoxin B1 (AFB1), ochratoxin A (OTA) level (Arıcı 2000; Colak et al. 2012; Ozden et al. 2012) and microbiological quality of tarhana (Ibanoglu at al. 1999; Erbas et al. 2005; Settanni et al. 2011; Sengun & Karapinar 2012), there is no study on the AFM1 level of Tarhana chips. Thus, the objective of this study was to investigate AFM1 contamination of Tarhana chips and to determine colour, proximate composition and textural properties.
Materials and methods Samples Forty Tarhana chips samples were collected randomly during August 2011 to September 2011 from different local producer in Kahramanamaraş, Turkey. Sampling sizes were between 500 and 1000 g. All samples were transported to the Celal Bayar University, Food Engineering Research Laboratory, divided into two portions in a sterile bag and stored at 4°C in the original packages before they were ground. One portion was used for AFM1 analysis and another portion for proximate and textural analysis. The samples were milled completely by a laboratory grinder. For textural and proximate analysis 5 g is taken and 10 g from the remaining ground sample is used for AFM1 analysis.
AFM1 analysis AFM1 levels were determined by a commercial test kit (RIDASCREEN®, R-Biofarm Darmstadt, Germany) with competitive ELISA (ELx 800, BioTek Instruments, Winooski, VT 05404, USA) and calculated by the Gen5 computer program. The test kit included different concentrations of standard solutions (0, 5, 10, 20, 40 and 80 pg/kg). The kit also included reagents and substrate/chromogen solutions, conjugates, stop solutions, buffer and washing solutions. The limit of detection of kits for AFM1 was 0.05 pg/kg. The recovery rate was 70–110%.
AFM1 test procedure 10 g of ground Tarhana chips was mixed with 100 mL pure water. The solution was extracted 5 min by shaking. The extract was centrifuged for 10 min at 10°C with 3500 × g. The upper cream layer was completely removed. The sublayer was used directly for AFM1
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analysis. 100 µL of standard solutions and samples prepared in duplicate were poured into the separate microtitre wells. After shaking gently, the plate was incubated for 30 min at room temperature (25°C). The wells were washed three times with 250 µL washing buffer. Thereafter 100 µL enzyme conjugate was added to each well and the plate was incubated for 15 min at room temperature (25°C). The washing steps were repeated three times with 250 µL washing buffer. 100 µL substrate/chromagen was added to all wells and the plate was incubated for 15 min at room temperature (25°C). After adding 100 µL stop solution to each well, absorbance was measured at 450 nm in the plate reader. Proximate analysis Protein, oil, salt, moisture, pH and ash content of Tarhana chips were determined as described in the Official Methods of Analysis Handbook of the Association of Analytical Chemists (1990). Texture profile analysis Texture profile analysis was used to determine instrumental hardness of the Tarhana chips samples. It was determined by a TA.XT II Plus Texture Analyzer (Vienna Court, Surrey, England). Original size Tarhana chips were used for analysis. A P-5 cylindrical probe was used and pre-test speed, test speed and post-test speed were stated as 2, 1 and 2 mm/sec, respectively. Hardness values of the samples were determined according to the graphics obtained by the TA.XT II Plus Texture Analyzer software. The maximum height of the first peak on the first compression was described as hardness (N) (Szczesniak 1963). Colour measurement The lightness (L* value), redness (a* value) and yellowness (b* value) of Tarhana chips were determined by a Hunter calorimeter (Minolta CR310, Osaka, Japan). Ground samples were placed into a petri dish lid. Six readings were taken per sample and their arithmetic mean was calculated. Results and discussion All data are given in the database. They are summarised in Table 1. Out of 40 samples, 21 contained AFM1, ranging from 0.5 to 36.6 ng/kg. Mean AFM1 level in positive samples was 17.6 ng/kg. This result indicated that AFM1 level of all samples was below the limit of 50 ng/kg of the Turkish Food Codex (Anonymous 2008). While a number of studies have been carried out to determine AFB1 and OTA levels of tarhana (Arıcı 2000; Colak et al. 2012;
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Table 1. AFM1 levels and physicochemical properties of Tarhana chips. Parameter
Mean
Minimum
Maximum
Aflatoxin M1 (ng/kg) Moisture % Oil % Protein % Salt % Ash % pH Hardness (N) Colour L* a* b*
17.6 7.6 5.9 15.3 2.6 4.4 3.8 5.0
0.5 4.6 0.7 7.9 1.3 2.4 3.5 1.3
36.6 9.6 11.6 24.4 3.9 6.9 4.0 9.6
72.9 4.8 24.7
55.3 2.3 21.7
81.4 14.0 32.1
Ozden et al. 2012), no studies have been carried out on AFM1 levels in tarhana. Ozden et al. (2012) reported the presence of OTA in 47 out of the 87 tarhana samples with levels ranging from 0.1 to 1.9 µg/kg. Colak et al. (2012) determined total aflatoxin and AFB1 levels in 138 tarhana samples collected from İstanbul, Turkey. In their study, 32 out of the 138 samples contained total aflatoxins ranging from 0.7 to 16.8 µg/kg. Also, 29 out of 139 samples contained AFB1 ranging from 0.2 to 13.2 µg/kg. In the same study 14 out of 138 tarhana samples (10%) were reported to exceed Turkish Food Codex limits (Colak et al. 2012). Morover, Arıcı (2000) detected 4 AFB1 positive samples out of 31 tarhana samples (Arıcı 2000). AFM1 is monohydroxylated derivate of AFB1 which is excreted into the milk of mammary glands of dairy cows as a result of feeding with aflatoxin contaminated feed (Allcroft et al. 1967; Asi et al. 2012). Therefore AFM1 is the typical mycotoxin in milk (Aycicek et al. 2005). Oil content of Tarhana chips was between 0.7 g/100 g and 11 g/100 g solid and the mean was 5.8 g/100 g solid. In a study, fried potato chips were found to contain 39.8 g/100 g solid, corn chips 36.6 g/100 g solid and corn chips 25.2 g/100 g solid (Moreira et al. 1999). Oil content of Tarhana chips (5.8 g/100 g solid) is much lower than any of these classical chips. Moreover, several researchers focused on reducing oil content of chips by using different production methods (Rima-Brncic et al. 2004; Garmakhany et al. 2008; Dueik & Bouchon 2011; Pandey & Moreira 2012; Kim & Moreira 2013). Thus, Tarhana chips might be an alternative for low energy and healthy snack food. Protein content of Tarhana chips was between 8.0–24.0 g/100 g solid with an arithmetic mean of 15.0 g/100 g solid. Randon-Villalobos et al. (2009) reported that, protein content means of corn tortilla chips were 9.1 g/100 g indicating that Tarhana chips had higher protein than corn tortilla chips (15.0 g/100 g solid).
Conclusion In conclusion, even though 21 samples out of 40 samples were contaminated with AFM1, the contamination level was lower than the limits in Turkish Food Codex and EU Regulations. Therefore, the AFM1 level in positive samples may not pose a risk to public health. Physicochemical analysis data showed that Tarhana chips had high protein and low oil and salt content, when compared to classical chips.
References Allcroft R, Roberts BA, Butler WH. 1967. Aflatoxin in milk. Food Cosmet Toxicol. 5:597–598. Alnouri FF, Duitschaever CL. 1974. The use of pure cultures for the preparation of kushuk. Can Inst Food Sci Technol J. 7:228–229. Anonymous. 1981. Tarhana Standard (TS 2282). Ankara (Turkey): Turkish Standard Institute. Anonymous. 2008. Türk Gıda Kodeksi (Tebliğ No:2008/26). Gıda Maddelerindeki bulaşanların maksimum limitleri hakkındaki tebliğ. Resmi Gazete 17.05.2008-26879. Available from: http://www.gidamo.org.tr/mevzuat/mevzuat_ detay.php?kod=70 Association of Analytical Chemists. 1990. Official methods of analysis. 15th ed. Washington (DC): Association of Analytical Chemists. Arici M. 2000. Microbiological studies and mycotoxin analysis of a fermented cereal product (Tarhana). ErnahrungsUmschau. 47:477. Asi MR, Iqbal SZ, Ariño A, Hussain A. 2012. Effect of seasonal variations and lactation times on aflatoxin M1 contamination in milk of different species from Punjab, Pakistan. Food Contr. 25:34–38. Aycicek H, Aksoy A, Saygi S. 2005. Determination of aflatoxin levels in some dairy and food products which consumed in Ankara, Turkey. Food Contr. 16:263–266. Colak H, Hampikyan H, Bingol EB, Cetin O, Akhan M, Turgay I. 2012. Determination of mould and aflatoxin contamination in Tarhana, a Turkish fermented food. Sci World J. 2012:218679. Daglioglu O. 2000. Tarhana as a traditional Turkish fermented cereal food. Its recipe, production and composition. Nahrung. 44:85–88. Dueik V, Bouchon P. 2011. Development of healthy low-fat snacks: understanding the mechanisms of quality changes during atmospheric and vacuum frying. Food Rev Int. 27:408–432. Elkak A, Atat OE, Habib J, Abbas M. 2012. Occurrence of aflatoxin M1 in cheese processed and marketed in Lebanon. Food Contr. 25:140–143. Erbas M, Certel M, Uslu MK. 2005. Microbiological and chemical properties of tarhana during fermentstion and storage as wetsensorial properties of tarhana soup. LWT. 38:409–416. European Commission. 2006. Regulation 2006/1881/EC of 19 December 2006 replacing Regulation (EC) 466/2001 setting maximum levels for certain contaminants in foodstuffs [Internet]. OJ L 364/5-24, 20.12.2006. Available from: http://eur-lex.europa.eu/LexUriServ/LexUriServ.do? uri=CONSLEG:2006R1881:20100701:EN:PDF Flegal KM, Carrol MD, Ogden CL, Johnson CL. 2002. Prevalence and trends in obesity among US adults, 1999–2000. J Am Med Assoc. 288:1723–1727. Garmakhany AD, Mirzaei HO, Nejad MK, Maghsudlo Y. 2008. Study of oil uptake and some quality attributes of potato
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Food Additives & Contaminants: Part B chips affected by hydrocolloids. Eur J Lipid Sci Technol. 110:1045–1049. Hayta M, Alpaslan M, Baysar A. 2002. Effect of drying methods on functional properties of tarhana: a wheat flour-yogurt mixture. J Food Sci. 67:740–744. Ibanoglu S, Ainsworth P, Wilson G, Hayes GD. 1995. The effect of fermentation conditions on the nutrients and acceptability of tarhana. Food Chem. 53:143–147. Ibanoglu S, Ibanoglu E. 1999. Rheological properties of cooked Tarhana, a cerealbased soup. Food Res Int. 32:29–33. Ibanoglu S, Ibanoglu E, Ainsworth P. 1999. Effect of different ingredients on the fermentation activity in tarhana. Food Chem. 64:103–106. International Agency for Research on Cancer. 2002. Acrylamide. In: IARC monographs on the evaluation of carcinogenic risks to humans [Internet]. Lyon (France): International Agency for Research on Cancer; p. 389–433. Available from: http:// monographs.iarc.fr/ENG/Monographs/vol82/mono82.pdf Kim T, Moreira RG. 2013. De-oiling and pretreatment for high-quality potato chips. J Food Process Eng. 36:267–275. Lineback DR, Coughlin JR, Stadler RH. 2012. Acrylamide in foods: a review of the science and future considerations. Ann Rev Food Sci Technol. 3:15–35. McCrory MA, Fuss PJ, McCallum JE, Yao M, Vinken AG, Hays NP, Roberts SB. 1999. Dietary variety within food groups: association with energy intake and body fatness in men and women. Am J Clin Nutr. 69:440–447. Medeiros Vinci R, Mestdagh F, De Meulenaer B. 2012. Acrylamide formation in fried potato products - present and future, a critical review on mitigation strategies. Food Chem. 15:1138–1154. Moreira RG, Castell-Perez ME, Barrufet MA. 1999. Deep fat frying: fundamentals and applications. Gaithersburg (MD): Chapman & Hall Food Science Book. Ozden S, Akdeniz AS, Alpertunga B. 2012. Occurrence of ochratoxin A in cereal-derived food products commonly consumed in Turkey. Food Contr. 25:69–74. Pandey A, Moreira RG. 2012. Batch vacuum frying system analysis for potato chips. J Food Process Eng. 35:863–873.
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R-Biopharm GmbH. 1999. Enzyme immunoassay for the quantitative analysis of aflatoxins. Ridascreen Aflatoxin M1 Art. No: R-1101. Darmstadt, Germany. Rendon-Villalobos JR, Bello-Perez LA, Agarma-Acevedo E, Islas-Hernandez JJ, Osorio-Diaz P, Tovar J. 2009. Composition and characteristics of oil extracted from flaxseed-added corn tortilla. Food Chem. 117:83–87. Rima-Brncic SR, Lelas V, Rade D, Simundic B. 2004. Decreasing of oil absorption in potato strips during deepfat frying. J Food Eng. 64:237–241. Saguy IS, Dana D. 2001. Integrated approach to deep fat frying: engineering, nutrition, health and consumer aspects. J Food Eng. 56:143–152. Saguy IS, Dana D. 2003. Integrated approach to deep fat frying: engineering, nutrition, health and consumer aspects. J Food Eng. 56:143–152. Sengun IY, Karapinar M. 2012. Microbiological quality of Tarhana, Turkish cereal based fermented food. Qual Assur Saf Crops Food. 4:17–25. Settanni L, Tanguler H, Moschetti G, Reale S. 2011. Evolution of fermenting microbiota in tarhana produced under controlled technological conditions. Food Microbiol. 28:1367–1373. Stadler RH, Blank I, Varga N, Robert F, Hau J, Guy PA, Robert MC, Riediker S. 2002. Acrylamide from Maillard reaction products. Nature. 419:449–450. Stadler RH, Scholz G. 2004. Acrylamide: an update on current knowledge in analysis, levels in food, mechanisms of formation, and potential strategies of control. Nutr Rev. 62:449–467. Szczesniak AS. 1963. Classification of textural characteristics. J Food Sci. 28:385–389. Tamime AY, Muir DD, Khaskheli M, Barclay MNI. 2000. Effect of processing conditions and raw materials on the properties of Kishk 1. Compositional and microbiological qualities. Lebensm Wiss Technol. 33:444–451. Van Egmond HP. 1994. Aflatoxins in milk. In: Eaton DL, Groopman JD, editors. The toxicology of aflatoxins: human health, veterinary, and agricultural significance. San Diego (CA): Academic Press, Inc; p. 65–381. Youssef MM. 1990. Instantization and evaluation of some traditional Egyptian foods. Food Chem. 38:247–254.
Food Additives & Contaminants: Part B: Surveillance Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/tfab20
Aflatoxin M1 in Tarhana chips a
b
Mustafa Özçam , Ersel Obuz & Halil Tosun
a
a
Department of Food Engineering, Faculty of Engineering, Celal Bayar University, Manisa, Turkey b
Department of Bioengineering, Faculty of Engineering, Celal Bayar University, Manisa, Turkey Accepted author version posted online: 11 Dec 2013.Published online: 20 Feb 2014.
To cite this article: Mustafa Özçam, Ersel Obuz & Halil Tosun (2014) Aflatoxin M1 in Tarhana chips, Food Additives & Contaminants: Part B: Surveillance, 7:3, 182-185, DOI: 10.1080/19393210.2013.874373 To link to this article: http://dx.doi.org/10.1080/19393210.2013.874373
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions
Food Additives & Contaminants: Part B, 2014 Vol. 7, No. 3, 182–185, http://dx.doi.org/10.1080/19393210.2013.874373
Aflatoxin M1 in Tarhana chips Mustafa Özçama*, Ersel Obuzb and Halil Tosuna a
Department of Food Engineering, Faculty of Engineering, Celal Bayar University, Manisa, Turkey; bDepartment of Bioengineering, Faculty of Engineering, Celal Bayar University, Manisa, Turkey
Downloaded by [UQ Library] at 23:45 03 November 2014
(Received 29 October 2013; accepted 8 December 2013) Tarhana chips are a popular traditional fermented food consumed widely in the Kahramanmaraş region of Turkey. Tarhana chips are different from many other types of fermented food in that they are produced in the form of tortilla chips. Cereal and yoghurt are the main ingredients in Tarhana chips. Aflatoxin M1 (AFM1) levels in dairy and dairy-based products are of concern for human health. To investigate AFM1 contamination, a total of 40 samples were collected from Kahramanmaraş region and AFM1 levels were determined by competitive enzyme-linked immunosorbent assay (ELISA). Furthermore, physicochemical characteristics of Tarhana chips were investigated and compared with classic fried chips in terms of nutritional value. Based on data obtained from enzyme-linked immunosorbent assay, 21 (52.5%) out of 40 samples contained AFM1 in the range 0.5–36.6 ng/kg, so AFM1 levels of all samples were below the legal limit. Keywords: Tarhana; chips; Aflatoxin M1; ELISA
Introduction Tarhana is a cereal and yoghurt-based fermented food with a very high consumption rate in Turkey. It is produced by mixing different raw materials such as wheat flour, yoghurt, vegetables, spices and yeast. The next step is fermentation (at 25–30°C during 1–7 days) and drying (Ibanoglu et al. 1999). There are four different types of tarhana, as given by the Turkish Standardization Institute: flour tarhana, semolina tarhana, goce (cracked wheat) tarhana and mixed tarhana (Anonymous 1981). Tarhana production methods differ depending on the region (Daglioglu 2000), but cereals and yoghurt are always the major component (Ibanoglu et al. 1995). There are some other products similar to tarhana in different countries such as kishk in Syria, Jordan and Egypt (Youssef 1990), kushuk in Iraq (Alnouri & Duitschaever 1974), trahana in Greece, atole in Scotland (Tamime et al. 2000) and tahanya/talkuna in Hungary and Finland (Hayta et al. 2002). Tarhana is generally consumed as soup in winter days (Ibanoglu & Ibanoglu 1999). But a different kind of tarhana called Tarhana chips are dried as a thin layer on nugget and usually consumed as tortilla chips instead of soup especially in the Kahramanmaraş region Turkey (Erbas et al. 2005). Obesity has become a major problem in the United States and in many Western countries (Flegal et al. 2002). The major factor causing obesity is high consumption of energy-dense foods, especially snack food (McCrory et al. 1999). Chips account for a high percentage of energy-dense snack foods. Most snack chips are deep fried in hot oil or fat, resulting in products that have a high fat content (Moreira et al. 1999). Consuming large amount of fats *Corresponding author. Email: [email protected] © 2014 Taylor & Francis
and oils, particularly saturated fats, increases coronary heart disease, hypertension, diabetes and cancer risk (Saguy & Dana 2003). In addition, the frying process can release acrylamide, which is classified in Group 2A as a “probable carcinogen to humans” (IARC 2002). It is formed via the Maillard reaction when asparagine and reducing sugars are heated at high temperatures (Stadler et al. 2002; Stadler & Scholz 2004). Potatoes have high amounts of asparagine and reducing sugars. Consequently, fried potato products, such as French fries and chips have been found to contain high levels of acrylamide (Lineback et al. 2012; Medeiros Vinci et al. 2012). However, Western consumers have increasing awareness about a relationship between nutrition, food and health (Saguy & Dana 2001). In recent years, a new diet lifestyle is gaining popularity and consumers have great interest in traditional food products because of their beneficial effect on health (Settanni et al. 2011). Within this framework, Tarhana chips can be considered a healthy alternative instead of classical high-fat fried chips, because Tarhana chips contain cereal and yoghurt, have lower fat and do not contain acrylamide. Yoghurt is one of the two major components of Tarhana chips (Ibanoglu et al. 1995). Hence, Tarhana chips can be recognised as a dairy (yoghurt)-based fermented food. Aflatoxin M1 (AFM1) levels in dairy and dairy-based products are of interest because of human health (Elkak et al. 2012). Yoghurt having low microbiological quality may increase AFM1 levels in Tarhana chips, when it is produced with locally supplied yoghurt which could be contaminated with AFM1. AFM1 is known to be hepatotoxic and carcinogenic, which could
Food Additives & Contaminants: Part B
Downloaded by [UQ Library] at 23:45 03 November 2014
cause mycotoxicosis (Van Egmond 1994). For this reason the European Union (European Commission, 2006) and Turkish Food Codex (Anonymous 2008) set maximum levels for AFM1 in food. Based on Turkish Food Codex, maximum level of AFM1 is 50 ng/kg in potentially risky food (Anonymous 2008). Although there are several studies on total aflatoxin, aflatoxin B1 (AFB1), ochratoxin A (OTA) level (Arıcı 2000; Colak et al. 2012; Ozden et al. 2012) and microbiological quality of tarhana (Ibanoglu at al. 1999; Erbas et al. 2005; Settanni et al. 2011; Sengun & Karapinar 2012), there is no study on the AFM1 level of Tarhana chips. Thus, the objective of this study was to investigate AFM1 contamination of Tarhana chips and to determine colour, proximate composition and textural properties.
Materials and methods Samples Forty Tarhana chips samples were collected randomly during August 2011 to September 2011 from different local producer in Kahramanamaraş, Turkey. Sampling sizes were between 500 and 1000 g. All samples were transported to the Celal Bayar University, Food Engineering Research Laboratory, divided into two portions in a sterile bag and stored at 4°C in the original packages before they were ground. One portion was used for AFM1 analysis and another portion for proximate and textural analysis. The samples were milled completely by a laboratory grinder. For textural and proximate analysis 5 g is taken and 10 g from the remaining ground sample is used for AFM1 analysis.
AFM1 analysis AFM1 levels were determined by a commercial test kit (RIDASCREEN®, R-Biofarm Darmstadt, Germany) with competitive ELISA (ELx 800, BioTek Instruments, Winooski, VT 05404, USA) and calculated by the Gen5 computer program. The test kit included different concentrations of standard solutions (0, 5, 10, 20, 40 and 80 pg/kg). The kit also included reagents and substrate/chromogen solutions, conjugates, stop solutions, buffer and washing solutions. The limit of detection of kits for AFM1 was 0.05 pg/kg. The recovery rate was 70–110%.
AFM1 test procedure 10 g of ground Tarhana chips was mixed with 100 mL pure water. The solution was extracted 5 min by shaking. The extract was centrifuged for 10 min at 10°C with 3500 × g. The upper cream layer was completely removed. The sublayer was used directly for AFM1
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analysis. 100 µL of standard solutions and samples prepared in duplicate were poured into the separate microtitre wells. After shaking gently, the plate was incubated for 30 min at room temperature (25°C). The wells were washed three times with 250 µL washing buffer. Thereafter 100 µL enzyme conjugate was added to each well and the plate was incubated for 15 min at room temperature (25°C). The washing steps were repeated three times with 250 µL washing buffer. 100 µL substrate/chromagen was added to all wells and the plate was incubated for 15 min at room temperature (25°C). After adding 100 µL stop solution to each well, absorbance was measured at 450 nm in the plate reader. Proximate analysis Protein, oil, salt, moisture, pH and ash content of Tarhana chips were determined as described in the Official Methods of Analysis Handbook of the Association of Analytical Chemists (1990). Texture profile analysis Texture profile analysis was used to determine instrumental hardness of the Tarhana chips samples. It was determined by a TA.XT II Plus Texture Analyzer (Vienna Court, Surrey, England). Original size Tarhana chips were used for analysis. A P-5 cylindrical probe was used and pre-test speed, test speed and post-test speed were stated as 2, 1 and 2 mm/sec, respectively. Hardness values of the samples were determined according to the graphics obtained by the TA.XT II Plus Texture Analyzer software. The maximum height of the first peak on the first compression was described as hardness (N) (Szczesniak 1963). Colour measurement The lightness (L* value), redness (a* value) and yellowness (b* value) of Tarhana chips were determined by a Hunter calorimeter (Minolta CR310, Osaka, Japan). Ground samples were placed into a petri dish lid. Six readings were taken per sample and their arithmetic mean was calculated. Results and discussion All data are given in the database. They are summarised in Table 1. Out of 40 samples, 21 contained AFM1, ranging from 0.5 to 36.6 ng/kg. Mean AFM1 level in positive samples was 17.6 ng/kg. This result indicated that AFM1 level of all samples was below the limit of 50 ng/kg of the Turkish Food Codex (Anonymous 2008). While a number of studies have been carried out to determine AFB1 and OTA levels of tarhana (Arıcı 2000; Colak et al. 2012;
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Table 1. AFM1 levels and physicochemical properties of Tarhana chips. Parameter
Mean
Minimum
Maximum
Aflatoxin M1 (ng/kg) Moisture % Oil % Protein % Salt % Ash % pH Hardness (N) Colour L* a* b*
17.6 7.6 5.9 15.3 2.6 4.4 3.8 5.0
0.5 4.6 0.7 7.9 1.3 2.4 3.5 1.3
36.6 9.6 11.6 24.4 3.9 6.9 4.0 9.6
72.9 4.8 24.7
55.3 2.3 21.7
81.4 14.0 32.1
Ozden et al. 2012), no studies have been carried out on AFM1 levels in tarhana. Ozden et al. (2012) reported the presence of OTA in 47 out of the 87 tarhana samples with levels ranging from 0.1 to 1.9 µg/kg. Colak et al. (2012) determined total aflatoxin and AFB1 levels in 138 tarhana samples collected from İstanbul, Turkey. In their study, 32 out of the 138 samples contained total aflatoxins ranging from 0.7 to 16.8 µg/kg. Also, 29 out of 139 samples contained AFB1 ranging from 0.2 to 13.2 µg/kg. In the same study 14 out of 138 tarhana samples (10%) were reported to exceed Turkish Food Codex limits (Colak et al. 2012). Morover, Arıcı (2000) detected 4 AFB1 positive samples out of 31 tarhana samples (Arıcı 2000). AFM1 is monohydroxylated derivate of AFB1 which is excreted into the milk of mammary glands of dairy cows as a result of feeding with aflatoxin contaminated feed (Allcroft et al. 1967; Asi et al. 2012). Therefore AFM1 is the typical mycotoxin in milk (Aycicek et al. 2005). Oil content of Tarhana chips was between 0.7 g/100 g and 11 g/100 g solid and the mean was 5.8 g/100 g solid. In a study, fried potato chips were found to contain 39.8 g/100 g solid, corn chips 36.6 g/100 g solid and corn chips 25.2 g/100 g solid (Moreira et al. 1999). Oil content of Tarhana chips (5.8 g/100 g solid) is much lower than any of these classical chips. Moreover, several researchers focused on reducing oil content of chips by using different production methods (Rima-Brncic et al. 2004; Garmakhany et al. 2008; Dueik & Bouchon 2011; Pandey & Moreira 2012; Kim & Moreira 2013). Thus, Tarhana chips might be an alternative for low energy and healthy snack food. Protein content of Tarhana chips was between 8.0–24.0 g/100 g solid with an arithmetic mean of 15.0 g/100 g solid. Randon-Villalobos et al. (2009) reported that, protein content means of corn tortilla chips were 9.1 g/100 g indicating that Tarhana chips had higher protein than corn tortilla chips (15.0 g/100 g solid).
Conclusion In conclusion, even though 21 samples out of 40 samples were contaminated with AFM1, the contamination level was lower than the limits in Turkish Food Codex and EU Regulations. Therefore, the AFM1 level in positive samples may not pose a risk to public health. Physicochemical analysis data showed that Tarhana chips had high protein and low oil and salt content, when compared to classical chips.
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