Thermo-oxidative degradation of some common edible oils during frying

Department of Chemical Technology, University College of Science & Technology, University of Calcutta, 92, Acharya Prafulla Chandra Road, Kolkata-700 009, India E-mail: mahuag@gmail.com, mgchemtech@caluniv.ac.in Fax: 91-33-23519755 Manuscript received 25 August 2012, revised 28 September 2012, accepted 28 September 2012 The present study includes the deterioration of four widely used frying oils in India, viz. soybean oil, sunflower oil, rice bran oil and palm olein oil during frying at higher temperature. The oil samples were heated at 180- 190 °C for 24 h along with potato chips and fried oil samples were collected after every 4 h. Fresh oil was never added to the frying vessel. The oil quality parameters viz. acid value, iodine value, peroxide value, p-anisidine value, conjugated diene and conjugated triene were determined. The investigation revealed that soybean oil possesses the least thermal stability. Though palm olein oil showed a greater thermal stability than others but from nutritional point of view, because of its higher degree of saturation, it is less suitable for human health. Considering all the aspects, rice bran oil came out as best option in the choice of frying oil