Thermal degradation of groundnut oil during continuous and intermittent frying
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The quality of refined groundnut oil, as affected by frying Poori, was assessed with respect to two types of frying operations viz., continuous frying and intermittent frying. Continuous frying was carried out consistently for 8 h, whereas intermittent frying was performed for 2 h everyday for 4 days for a total of 8 frying hours. The purpose of the study was to compare the level of deterioration that occurred during the two operations. Among the parameters studied, peroxide value (11.3 ± 0.26 meqO2/kg), anisidine value (172.4 ± 2.71), diene value (1.57 ± 0.095), oxidized fatty acid (2.6 ± 0.17%) and viscosity (103.8 ± 2.5 mPa s−1), were found to be higher after 8 h due to intermittent frying. The corresponding values 4.9 ± 0.15, 133.3 ± 0.49, 0.811 ± 0.04, 0.38 ± 0.023 and 81.8 ± 2.02 were observed in continuous frying. Parameters such as iodine value, unsaturated fatty acids, saponification value and smoke point decreased significantly (P < 0.5) due to intermittent frying. Results showed that intermittent frying caused more quality degradation to GNO than continuous frying.
KeywordsContinuous frying Intermittent frying Quality Oxidation Hydrolysis
Authors are grateful to the Director, CFTRI for his keen interest in the study. Thanks are due to Dr. KSMS Raghavarao, Dr. BR Lokesh, Mr. KK Bhat, Dr. K Venkatesh Murthy and Dr. R Ravi. A special thank to Dr. Chetana R. for her support during frying study.
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