Investigating the amount of TFAs, CLAs and ω6/ω3 of various brands of corn oil heated at different time-temperature treatments.

Abstract

A qualitative and quantitative analysis of trans fatty acids (TFAs), conjugated linoleic acids (CLAs) and linoleic acid/α-linolenic acid (ω6/ω3) in eleven different brands of fresh and heated corn oil was investigated. Corn oil was subjected to thermal treatment at 180, 210 and 230°C for 4, 8 and 12h. The kinds of fatty acids were almost the same in all eleven brands of corn oil, but there were differences in the quantities of TFAs, CLAs and ω6/ω3 among the brands. The formation of TFAs in different brands of corn oil increased slowly at 180°C and rapidly at 230°C with the maximum increase of 28 and 374%, respectively. The formation of CLAs also increased during the heating with the amount of 0.00-0.32g/100g in fresh corn oil and 0.71-1.12g/100g in corn oil heated at 230°C for 12h. The value of ω6/ω3 was high in corn oil and increased with heating temperature and time. The largest rise of ω6/ω3 can reach upwards of 239:1. The results showed that temperature control was essential for maintaining the quality and nutritional value of corn oil.