The effect of blanching process on acrylamide formation in potato crisps

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International Journal of Farming and Allied Sciences Available online at www.ijfas.

1 International Journal of Farming and Allied Sciences Available online at IJFAS Journal / / 31 December, 2014 ISSN IJFAS The effect of blanching process on acrylamide formation in potato crisps Dorin Bakhtiary 1*, Simin Asadollahi 2 and Seyed Ali Yasini Ardakani 3 1.Department of Food Science and Technology college of Agriculture, Yazd Science and Research Branch, Islamic Azad University, Yazd, Iran 2.Department of Food Science and Technology, Agricultural faculty, Varamin-Pishva Branch, Islamic Azad University, Varamin, Iran 3.Department of Food Science and Technology college of Agriculture, Yazd Science and Research Branch, Islamic Azad Uni versity, Yazd, Iran Corresponding author: Dorin Bakhtiary ABSTRACT: Acrylamide, a probable carcinogen, is formed via the Maillard reaction between reducing sugars and the amino acid asparagines during heating of carbohydrate-rich foods. Potatoes contain high levels of these precursors, and thus potato crisps can contain high levels of acrylamide. In this study, the effect of blanching process on the concentration of acrylamide content was studied in potato crisps. Prior to frying, potato slices (Agria variety, diameter: 37 mm, width: 1.5 mm) were blanched for 3 min in hot water at 50 C, 70 C and 90 C and deep-fat fried for 5 min at 180 C. Unblanched potatoe slices were considered as the control. Acrylamide content was determined by GC-ECD. Average acrylamide contents for control and blanched samples at 50 C, 70 C and 90 C were 1140, 880, 625 and 455 µg/kg (ppb) after frying respectively. Results showed that blanching process caused significant decreases in acrylamide content of fried potato. It was more efficient at 90 C for 3 min, with an average reduction of 60%. In conclusion, blanching was an efficient way to reduce acrylamide content in potato crisps. Keywords: Acrylamide, Blanching process, Unblanched potato slices, Potato crisps INTRODUCTION Potato is the raw food material that has been used the most in frying operations due to the high demand of consumers all over the world (Pedreschi., 2007). Detection of high concentrations of acrylamide in heated starch rich foodstuffs, such as potato, by the Swedish National Food Administration in April 2002 attained public concern because this product is a suspected human carcinogen (Chico Galdo, 2006). Maillard reaction is suggested as the major mechanism of acrylamide formation in fried potatoes (Stadler., 2004). The precursors of this reaction for fried potatoes are glucose, fructose and asparagines (Becalski., 2003). So, several methods based in diminishing or eliminating acrylamide precursors have been implemented (Tareke., 2000). Acrylamide formation in foods is influenced by several factors, including processing temperature, time, content and species of reducing sugars and amino acids, ph, moisture content and frying oils, indicating that acrylamide in foods can be decreased by changing processing technology (Ciesarova, 2004). In the past years, many strategies aiming to reduce acrylamide formation in potato products have been proposed (Amrein., 2007). The selection of potato varieties having a low concentration of free carbohydrates and the use of appropriate storage conditions are of pivotal importance (Biedermann., 2003). Many studies demonstrated that it is possible to define time-temperature processing conditions which guarantee low

2 acrylamide concentration and the retention of sensorial properties in terms of color, flavor, and starch gelatinization (Pedreschi., 2006; Granda., 2004). Pedreschi. (2004) showed that increasing the frying temperature from C resulted in a marked increase in acrylamide levels. The former authors also showed that the use of low-temperature vacuum frying reduced acrylamide levels (Granda., 2004). Techniques implemented prior to thermal processing also reduce acrylamide formation. The principal objective of pretreatments of potato pieces is either to minimize the concentration of acrylamide precursors in potato tubers or to minimize or to inhibit Maillard reaction during frying (Pedreschi., 2004; Motthaus., 2004; Knustsen., 2009). Soaking or blanching of the raw product can reduce acrylamide content in the cooked product (Haase, 2003; Grob., 2003; Pedreschi., 2004, 2005). However, Williams et al. (2005) found that inclusion of a water soak prior to frying had no effect on acrylamide formation. A further reduction in acrylamide levels can be achieved by immersion of the raw product in an acidic solution prior to cooking (Jung., 2003; Kita., 2004; Pedreschi., 2004). This method is particularly effective as it enhances the extraction of reducing sugars and amino acids from the product. Other pre-treatments shown to reduce acrylamide formation include addition of a flavanoid spice mix (Fernandez., 2003), use of asparginase to breakdown asparagines in the raw product (Zyzak., 2004) and the use of genetically modified potatoes having a reduced content of soluble sugars (Soyka., 2004). In a recent paper, ferulic acid, hydrogen peroxide, ferulic acid combined with H2O2 or Fe2+, tea catechin, NaHCO3 and NaHSO3 were used to test the eliminating capacity for acrylamide under different temperatures and it was found that combination of ferulic acid with H2O2 or Fe2+ showed highest efficiency for eliminating acrylamide (Ou et al., 2004). Also, Levine and Smith (2005) found that NaHCO3, NH4HCO3, cysteine, sodium bisulfate and ascorbate could eliminate acrylamide; and citric acid, ferulic acid and NaCl decreased the amount of acrylamide produced. In addition, pre-treatment with the enzyme L-asparaginase is sufficient to reduce acrylamide content, since L-asparagine is considered to be one of the main precursors for the acrylamide formation in foods (Friedman, 2003). The aim of this study was to investigate the effect of blanching process on the concentration of acrylamide content in potato crisps. MATERIALS AND METHODS Materials For this research 10 kg of potatoes (Solanum tuberosum L.), Agria variety, were purchased from Seed and Plant Improvement Institute of Iran and stored at 10 until preparing chips. For frying potatoes, refined, bleached and deodorized palm olein oil, was purchased from Behshahr factory. All chemicals and solvents used were purchased from Merck (Darmstadt, Germany) Methods Preparation of potato crisps Potato crisps (Slices) Potato tubers (Variety Agria) were washed and after peeling, slices (diameter: 37 mm, width: 1.5 mm) were prepared by using a mechanical slicer (Italimport SRL, Model 90915, China). Blanching treatment Slices were rinsed immediately after cutting for 1 min in distilled water to eliminate some starch adhering to the surface prior to frying. Blanched samples were prepared by heating raw slices in 4 l of hot water at 50 C, 70 C and 90 C for 3 min. After blanching potato slices were cooled in ice water for 10 min. Blanched slices were drained and fried at 180. Unblanched potatoe slices were considered as the control. Frying condition 100 g of each treatment were fried in an electric deep fryer with a capacity of 3 Lit of oil at 180 for 5 min in palm olein oil. After frying, the samples were dried to remove excess oil. 1221

3 Determination of Acrylamide Method of measuring acrylamide by Gas Chromatography which is equipped with an electron capture detector (ECD) is based on extraction of the acrylamide from defatted sample with sodium chloride and derivatization of acrylamide with bromine and then tracking it by an electron capture detector (ECD). Manner of extraction The samples were prepared for acrylamide analysis using a procedure described by Lehotay and Mastovska (2006). In the first stage, 5/6 g of the homogeneous sample were mixed with 500 ng/g of meta acrylamide as an internal standard, 5 ml of hexane solution and distilled water and acetonitrile in the equal ratio by vortex mixer for 15 minutes. Then, 5 g of sodium sulfate anhydrous and sodium chloride were added to it. The mixture was centrifuged at 4500 rpm for 5 minutes and after using ultrasonic for 30 minutes, the acetonitrile layer was separated completely. Manner of derivatization The collected acetonitrile layer was brominated based on a procedure described by Tareke and Rydber (2002). For this aim, potassium bromide, hydrobromic acid and saturated bromine water were used. Obtained solution was kept in the refrigerator at 4 for a day. Then, the excess of bromine became colorless by adding some drops of sodium thiosulfate solution and this solution was extracted twice with 65 ml of ethyl acetate. The obtained organic phase was dried with 1 g of sodium sulfate and transferred in to rotary vacuum evaporator. Then the solution was concentrated under the nitrogen gas till a volume of 250 µl. Finally, 1 µl from each of prepared samples was injected into the capillary column (30 m 0/25 mm 0/25 µm) of GC/ECD. Four standard solutions of acrylamide were prepared with volumes of 10, 15, 20, 25 ml and were extracted and brominated on the basis of procedure described for the samples. The calibration curve was generated by injecting 1 µl from each of acrylamide standards into the GC/ECD and acrylamide concentration formed in the samples was determined by using the calibration curve (Figure1). Figure1. GC-ECD Calibration Curve Statistical analysis The experiments were carried out in the completely randomized design (CRD) in triplicates. The average was compared with each other by Duncan method. Analysis of variance (ANOVA) and comparison of averages was done by SPSS 16.0 software. RESULTS AND DISCUSSION As shown in figure 2, Average acrylamide contents for control and blanched samples at 50 C, 70 C and 90 C were 1140, 880, 625 and 455 µg/kg (ppb) after frying respectively. Acrylamide formation was higher in the control than in blanched samples suggesting that blanching process caused significant decreases in acrylamide content of fried potato. Similar results were reported recently (El-Saied., 2008; Viklund., 2010). Blanching could reduce the content of glucose and asparagines in potato slices by leaching these compounds into hot or warm water leading to significant lower acrylamide formation than in unblanched potato chips (Pedreschi.,2004). In this study, blanched Slices at 50 C, 70 C and 90 C for 3 min, showed on average a reduction of acrylamide formation of 23%, 45% and 60% respectively, when they were compared against the control. The highest decrease was observed for those samples blanched at 90 C with an average reduction of 60%. Similar result were reported by Haase et al. (2003) who showed that a reduction of the sugar content 1222

by blanching could reduce the acrylamide concentration by about 60% according to the raw material (potato variety and field site) and the production process variables (e.g. blanching conditions and frying temperature).

4 by blanching could reduce the acrylamide concentration by about 60% according to the raw material (potato variety and field site) and the production process variables (e.g. blanching conditions and frying temperature). Figure 2. Acrylamide content of control and blanched potato strips. Control corresponds to unblanched potato strips. Numbers 1, 2 and 3 indicate the blanched potato strips at 50 C, 70 C and 90 C for 3 min respectively CONCLUSION Results showed that blanching process caused significant decreases in acrylamide content of fried potato. It was more efficient at 90 C for 3 min, with an average reduction of 60%. In conclusion, blanching was an efficient way to reduce acrylamide content in potato crisps, in addition blanching samples resulted in prepared potato strips lighter in color than those of the control (visual observations). REFERENCES Amrein TM, Andres L, Escher F and Amado R Occurrence of acrylamide in selected foods and mitigation options. Food Addit. Contam 24: Biedermann-Brem S, Noti A, Grob K, Imhof D, Bazzocco D and Pfefferle A How much reducing sugar may potatoes contain to avoid excessive acrylamide formation during roasting and baking. Eur. Food Res. Technol 217: Becalski A, Lau B, Lewis D and Seaman S Acrylamide in foods: Occurrence, sources, and modeling. Journal of Agricultural and Food Chemistry 51, Ciesarova Z, Balasova V, Kiss E, Kolek E, Simko P and Kovac M Comparison of two methods for acrylamide determination and dietary intake of acrylamide from potato crisps in Slovakia. Chemical Reactions in Foods V 22, Dequanter M, Friedman M and Van Sande J Acrylamide, an in vivo thyroid carcinogenic agent, induces DNA damage in rat thyroid cell lines and primary cultures. Molecular and cellular Endocrinology, 257, 6-14 Fernandez S, Kurppa L and Hyvonen L Content of acrylamide decreased in potato chips with addition of a proprietary flavonoid spice mix (Flavomare) in frying. Innovations in Food Technology 18, Friedman M Chemistry, biochemistry, and safety of acrylamide. A review. Journal of Agricultural and Food Chemistry 51, Granda C, Moreira RG and Tichy SE Reduction of acrylamide formation in potato chips by low-temperature vacuum frying. Journal of Food Science 69, E405-E411. Grob K, Biedermann M, Biedermann B, Noti A, Imhof D, Amrein T, Pfefferle A and Bazzocco D French fries with less than 100 mug/kg acrylamide. A collaboration between cooks and analysts. European Food Research and Technology 217, Haase NU, Matthaus B and Vosmann K Acrylamide formation in foodstuffs - minimising strategies for potato crisps. Deutsche Lebensmittel Rundschau 99(3), Jung MY, Choi DS and Ju JW A novel technique for limitation of acrylamide formation in fried and baked corn chips and in french fries. Journal of Food Science 68, Kita A, Brathen E, Knutsen SH and Wicklund T Effective ways of decreasing acrylamide content in potato crisps during processing. Journal of Agricultural and Food Chemistry, 55 (23), Knutsen SH, Dimitrijevic S, Molteberg EL, Segtnan VH, Kaabera L and Wicklund T The influence of variety, agronomical factors and storage on the potential for acrylamide formation in potatoes grown in Norway, LWT-Food Science and Technology 42: Lehotay J and Mastovska K Rapid sample preparation method for LC-MS/MS or GC-MS analysis of acrylamide in various food matrices. Journal of Agricultural and Food Chemistry 54: Levine RA and Smith RE Sources of variability of acrylamide levels in a cracker model. J. Agric. Food Chem 53: Matthaus B, Hasse NU and Vosmann K Factors affecting the concentration of acrylamide during deep-fat frying of potatoes. European Journal of Lipid Science and Technology 106: Oue SY, Lin QL, Wang Y, Huang CH and Huang XS Effect of several additives on destroying acrylamide. China Oils Fats 29: Pedreschi F, Kaack K and Granby K Reduction of acrylamide formation in potato slices during frying. Lebensmittel-Wissenschaft and Technologie 37, Pedreschi F and Zaniga RM Acrylamid and oil reduction in fried potato: A review.global Science books,3(2), Pedreschi F, Kaack K and Granby K Acrylamide content and colour development in fried potato strips. Food Res. Int 36: Pedreschi F, Kaack K, Granby K and Troncoso E Acrylamide reduction under different pretreatments in french fries. J. Food Eng., 79: Stadler RH, Robert F, Riediker S, Varga N, Davidek T, Devaud S, Goldmann T, Hau J and Blank I In-depth mechanistic study on the formation of acrylamide and other vinylogous compounds by the Maillard reaction. J. Agric. Food Chem 52:

5 Soyka S, Frohberg C, Quanz M and Essigmann B Process for reducing the acrylamide content of heat-treated foods. European PCT Patent Application, no: WO Tareke E, Rydberg P, Karlsson P, Eriksson S and Tornqvist M Acrylamide: a cooking carcinogen? Chemistry Research Toxicology, 13, Tareke E and Rydberg P Analysis of acrylamide, a carcinogen formed in heated foodstuffs. Journal of Agricultural and Food Chemistry 50: Williams JSE Influence of variety and processing conditions on acrylamide levels in fried potato crisps. Food Chemistry 90, Zyzak DV, Sanders RA, Stojanovic M, Gruber DC, Lin PYT, Villagran MDM, Howie JK and Schafermeyer RG Method for reducing acrylamide in foods, foods having reduced levels of acrylamide, and article of commerce. United States Patent Application Pub lication, No. US 2004/

Impact of Soaking in Salt Solutions after Blanching on Acrylamide Formation and Sensorial Quality of Potato Chips

Impact of Soaking in Salt Solutions after Blanching on Acrylamide Formation and Sensorial Quality of Potato Chips Dorin Bakhtiary Department of Food Science and Technology, Payame Noor University (PNU),