Citation:Senanayake, C.M., Jayathilaka, N. and Seneviratne, K.N. 2016. Effect of Repeated Heating on The Oxidative Degradation of White Coconut Oil and Soy Bean Oil. In proceedings of the 17th Conference on Postgraduate Research, International Postgraduate Research Conference 2016, Faculty of Graduate Studies, University of Kelaniya, Sri Lanka. p 153.
Date:2016
Abstract:
Repeated heating of cooking oils is a common practice used mainly to save the cost in food
preparations. The aim of the present study was to investigative the effect of repeated heating on
the oxidative degradation of frying oils (white coconut oil and soy bean oil). Initially, fresh
potatoes were peeled off and sliced into uniform thickness (4×0.3×0.3 cm3). Sliced potatoes
(batches of 25 g) were fried in 100 mL portions of white coconut oil (WCO) and soy bean oil
(SO) separately at 180±5 °C for 10 minutes. The oils were reused for 2 more frying cycles over
a span of 3 days (1 frying cycle per day). In each day, an amount of fresh oil was added to make
the volume of frying oil in to 100 mL. After each frying cycle, oil samples were collected from
the frying pan and by extraction of fat with n-hexane from potato chips. Level of oxidation of
frying oils and lipid extracted from potato chips were assessed by measuring the peroxide value
(PV) and thiobarbituric acid reactive substances (TBARS).
Table 01 states the results of PV and TBARS. Both PV and TBARS of frying oils and lipid
extracted from potato chips increased as the number of frying cycles were increased (Table 01).
Fried SO (FSO) and lipid extracted from potato chips fried in SO (PSO) showed higher PV and
TBARS values than that of fried WCO (FWCO) and lipid extracted from potato chips fried in
WCO (PWCO) in every frying cycle (Table 01).
