Effect of frying cycles on physical, chemical and heat transfer quality of rice bran oil during deep-fat frying of poori: An Indian traditional fried food

• Published in: Food and bioproducts processing Vol. 90; no. 2; pp. 249 - 256
• Main Authors: Debnath, Sukumar, Rastogi, Navin K., Gopala Krishna, A.G., Lokesh, B.R.
• Format: Journal Article
• Language: English
• Published: Rugby Elsevier B.V 01.04.2012; Institution of Chemical Engineers
• Subjects: Biological and medical sciences; Deep-fat frying; Fat industries; Food industries; Fundamental and applied biological sciences. Psychology; Heat transfer coefficient; Oryza sativa; Poori; Rice bran oil; Viscosity; Viscosity; Deep-fat frying; Heat transfer coefficient; Poori; Rice bran oil; Heat treatment; Deep-frying; Quality; Fat; Vegetable oil; Edible oil; Cycle; Heat transfer; Food
• ISSN: 0960-3085; 1744-3571
• DOI: 10.1016/j.fbp.2011.05.001

► Rice bran oil contains components such as γ-oryzanol, phytosterols, tocotrienols and tocopherols, which renders the oil resistance to thermal oxidation and deterioration during frying. ► The convective heat transfer coefficient of rice bran oil was found to decrease with an increase in frying cycle due to increase in viscosity of oil for every frying cycle. ► The changes in total polar material which is an indicator for deterioration of oil indicated that the maximum numbers of frying cycles could be used for rice bran oil was 28. Beyond these numbers of frying cycles the total polar material crossed 24%. The present work deals with the effect of frying cycles on physical, chemical and heat transfer quality of rice bran oil (RBO) during the preparation of poori (an Indian traditional fried food) by deep-fat frying. The frying was carried out in intermittent mode (5 batches each for 3min in a day without any time lag) and repeated for 6 frying cycles. Result indicated that in first two cycles, free fatty acid content, peroxide value and total polar materials increased, while radical scavenging activity decreased. Further increase in frying cycles did not result in any significant changes in these parameters (p>0.05). Similar trends were observed for these parameters in case of heating. Relative amounts of total saturated fatty acids increased due to marginal decrease in total unsaturated fatty acids content during frying cycles, however, no significant change was observed during heating. The convective heat transfer coefficient was found to decrease with an increase in frying cycle due to increase in kinematic viscosity of RBO for every frying or cycles. Despite the marginal changes in physical and chemical properties, there was no significant difference (p>0.05) in the sensory characteristics of poori prepared in oil subjected to different cycles of frying.