Abstract    The effect of frying pressure on the kinetics of color changes during atmospheric and vacuum deep fat frying of Reshteh Khoshkar has been studied. The Hunter color parameters redness, yellowness, lightness and total color difference were used to estimate color changes during frying as a function of process. Lightness (L*) decreased from 85.37 to 75.01 with vacuum frying time, while redness (a*), yellowness (b*) and total color difference increased from -2.09, 4.92 and 0 to 1.22, 37.01 and 31.56, respectively. It was observed that the severity of colour change was higher in atmospheric frying process than the vacuum frying process. The changes in color parameters were modeled by zero-order, first-order and a combined kinetics model. The two first-order and combined kinetics models fitted properly the values of color changes during frying, with good coefficient of determination. The combined model used can describe the experimental colour parameters better than the other studied kinetics models.

Keywords    Vacuum frying; Color; Kinetics

چکیده    در این پژوهش اثر فشار سرخ کردن بر تغییرات رنگ رشته خوشکار طی سرخ کردن عمیق بررسی شد. پارامترهای رنگی هانتر شامل زردی، قرمزی، روشنایی و تغییرات کلی رنگ برای تخمین تغییرات رنگ طی سرخ کردن به‌عنوان تابعی از فرایند مورداستفاده قرار گرفتند. پارامتر روشنایی با گذشت زمان سرخ کردن طی خلأ از 37/85 به 01/75 کاهش یافت درحالی‌که پارامترهای زردی، قرمزی و تغییرات کلی رنگ به ترتیب از 09/2، 92/4 و 0 به 22/1، 01/37 و 56/31 افزایش یافتند. مشاهده شد که شدت تغییرات رنگ در فرایند سرخ کردن تحت شرایط اتمسفری بیشتر از شرایط تحت خلأ بود. مدل‌های درجه صفر، درجه اول و مدل مرکب برای بررسی تغییرات رنگ به کار رفتند. نتایج نشان دادند که تغییرات زردی، قرمزی، روشنایی و تغییرات کلی رنگ با هر دو مدل درجه اول و مدل مرکب قابل‌بیان هستند. مدل مرکب فراسنجه های رنگ مورد آزمون را بهتر از سایر مدل‌های سینتیکی موردبررسی تشریح کرد.

References    1.      Dana, D. and Saguy, I. S., "Review: Mechanism of oil uptake during deep-fat frying and the surfactant effect-theory and myth", Advances in Colloid and Interface Science,  Vol. 128, (2006), 267-272. 2.      Krokida, M., Oreopoulou, V., Maroulis, Z. and Marinos-Kouris, D., "Colour changes during deep fat frying", Journal of Food Engineering,  Vol. 48, No. 3, (2001), 219-225. 3.      Teruel, M. d. R., Gordon, M., Linares, M. B., Garrido, M. D., Ahromrit, A. and Niranjan, K., "A comparative study of the characteristics of french fries produced by deep fat frying and air frying", Journal of Food Science,  Vol. 80, No. 2, (2015), E349-E358. 4.      Andres-Bello, A., Garcia-Segovia, P. and Martinez-Monzo, J., "Vacuum frying: An alternative to obtain high-quality dried products", Food Engineering Reviews,  Vol. 3, No. 2, (2011), 63-78. 5.      Shahidi, S. A., Mohebbi, M., Motamedzadegan, A., Ziaiifar, A. M., Abolfazli, E. J. and Mortazavi, S. A., "Evaluation of atmospheric and vacuum frying on properties of deep fat fried reshte-khoshkar", Journal of Research and Innovation in Food Science and Technology, Vol. 2, No. 2, (2013), 179-192. 6.      Shyu, S.-L., Hau, L.-B. and Hwang, L. S., "Effect of vacuum frying on the oxidative stability of oils", Journal of the American Oil Chemists' Society,  Vol. 75, No. 10, (1998), 1393-1398. 7.      Granda, C., Moreira, R. and Tichy, S., "Reduction of acrylamide formation in potato chips by low‐temperature vacuum frying", Journal of Food Science,  Vol. 69, No. 8, (2004), E405-E411. 8.      Da Silva, P. F. and Moreira, R. G., "Vacuum frying of high-quality fruit and vegetable-based snacks", LWT-Food Science and Technology,  Vol. 41, No. 10, (2008), 1758-1767. 9.      Dueik, V., Robert, P. and Bouchon, P., "Vacuum frying reduces oil uptake and improves the quality parameters of carrot crisps", Food Chemistry,  Vol. 119, No. 3, (2010), 1143-1149. 10.    Shyu, S.-L. and Hwang, L. S., "Effects of processing conditions on the quality of vacuum fried apple chips", Food Research International,  Vol. 34, No. 2, (2001), 133-142. 11.    Troncoso, E., Pedreschi, F. and Zuniga, R., "Comparative study of physical and sensory properties of pre-treated potato slices during vacuum and atmospheric frying", LWT-Food Science and Technology,  Vol. 42, No. 1, (2009), 187-195. 12.    Amiryousefi, M. R., Mohebbi, M. and Khodaiyan, F., "Kinetics of mass transfer in microwave precooked and deep-fat fried ostrich meat plates", Food and Bioprocess Technology,  Vol. 5, No. 3, (2012), 939-946. 13.    Nasiri, F. D., Mohebbi, M., Yazdi, F. T. and Khodaparast, M. H. H., "Kinetic modeling of mass transfer during deep fat frying of shrimp nugget prepared without a pre-frying step", Food and Bioproducts Processing,  Vol. 89, No. 3, (2011), 241-247. 14.    Sundaria, A., Neelamegamb, P. and Subramanianc, C., "Drying kinetics of muscat grapes in a solar drier with evacuated tube collector", International Journal of Engineering-Transactions B: Applications,  Vol. 27, No. 5, (2013), 811-818. 15.    Ubale, A., Pangavhane, D. and Autic, A., "Experimental and theoretical study of thompson seedless grapes drying using solar evacuated tube collector with force convection method", International Journal of Engineering-Transactions C: Aspects,  Vol. 28, No. 12, (2015), 1796-1801. 16.    Karim, A. A., Sulebele, G., Azhar, M. and Ping, C., "Effect of carrageenan on yield and properties of tofu", Food Chemistry,  Vol. 66, No. 2, (1999), 159-165. 17.    Cai, T., Chang, K., Shih, M., Hou, H. and Ji, M., "Comparison of bench and production scale methods for making soymilk and tofu from 13 soybean varieties", Food Research International,  Vol. 30, No. 9, (1997), 659-668. 18.    Ateba, P. and Mittal, G., "Dynamics of crust formation and kinetics of quality changes during frying of meatballs", Journal of Food Science,  Vol. 59, No. 6, (1994), 1275-1278. 19.    Mariscal, M. and Bouchon, P., "Comparison between atmospheric and vacuum frying of apple slices", Food Chemistry,  Vol. 107, No. 4, (2008), 1561-1569. 20.    Ibarz, A., Pagan, J. and Garza, S., "Kinetic models for colour changes in pear puree during heating at relatively high temperatures", Journal of Food Engineering,  Vol. 39, No. 4, (1999), 415-422. 21.    Garza, S., Ibarz, A., Pagan, J. and Giner, J., "Non-enzymatic browning in peach puree during heating", Food Research International,  Vol. 32, No. 5, (1999), 335-343. 22.    Carabasa-Giribet, M. and Ibarz-Ribas, A., "Kinetics of colour development in aqueous glucose systems at high temperatures", Journal of Food Engineering,  Vol. 44, No. 3, (2000), 181-189. 23.    Ngadi, M., Li, Y. and Oluka, S., "Quality changes in chicken nuggets fried in oils with different degrees of hydrogenatation", LWT-Food Science and Technology,  Vol. 40, No. 10, (2007), 1784-1791. 24.    Sosa-Morales, M. E., Orzuna-Espiritu, R. and Velez-Ruiz, J. F., "Mass, thermal and quality aspects of deep-fat frying of pork meat", Journal of Food Engineering,  Vol. 77, No. 3, (2006), 731-738. 25.    Velez‐Ruiz, J. and Sosa‐Morales, M., "Evaluation of physical properties of dough of donuts during deep‐fat frying at different temperatures", International Journal of Food Properties,  Vol. 6, No. 2, (2003), 341-353. 26.    Baik, O. and Mittal, G., "Kinetics of tofu color changes during deep-fat frying", LWT-Food Science and Technology,  Vol. 36, No. 1, (2003), 43-48. 27.    Kim, T. and Moreira, R. G., "De‐oiling and pretreatment for high‐quality potato chips", Journal of Food Process Engineering,  Vol. 36, No. 3, (2013), 267-275. 28.    Hashemi Shahraki, M., Ziaiifar, A., Kashaninejad, S. and Ghorbani, M., "Optimization of pre‐fry microwave drying of french fries using response surface methodology and genetic algorithms", Journal of Food Processing and Preservation,  Vol. 38, No. 1, (2014), 535-550. 29.    Maskan, M., "Kinetics of colour change of kiwifruits during hot air and microwave drying", Journal of Food Engineering,  Vol. 48, No. 2, (2001), 169-175. 30.    Baixauli, R., Salvador, A., Fiszman, S. M. and Calvo, C., "Effect of the addition of corn flour and colorants on the colour of fried, battered squid rings", European Food Research and Technology,  Vol. 215, No. 6, (2002), 457-461. 31.    Pedreschi, F., Bustos, O., Mery, D., Moyano, P., Kaack, K. and Granby, K., "Color kinetics and acrylamide formation in nacl soaked potato chips", Journal of Food Engineering,  Vol. 79, No. 3, (2007), 989-997. 32.    Sahin, S., "Effects of frying parameters on the colour development of fried potatoes", European Food Research and Technology,  Vol. 211, No. 3, (2000), 165-168. 33.    Pedreschi, F., Leon, J., Mery, D., Moyano, P., Pedreschi, R., Kaack, K. and Granby, K., "Color development and acrylamide content of pre-dried potato chips", Journal of Food Engineering,  Vol. 79, No. 3, (2007), 786-793. 34.             Hutchings, J., "Food color and appearance. Gaithersburg, Md.", Aspen Publishers, Inc, (1999).