Oxidative stability and compositional characteristics of oil from microwave irradiated black cumin seed under accelerated oxidation condition

Abstract

The present work evaluated the impact of microwave pre-treatment on the storage stability, fatty acids and triacylglycerol contents in black cumin seed oil (BCO) during storage at 62 ºC. During storage, the oxidative indicator values (free acidity, peroxide value, p-anisidine value, TOTOX, specific extinctions and thiobarbituric acid) for the oils increased faster in untreated oil samples than in the microwaved samples. The degradation rate of polyunsaturated fatty acids (PUFAs) and triacylglycerol species (LLL and OLL) during storage were higher in untreated samples compared to treated ones, indicating that oxidation proceeded more slowly in the treated samples. During storage, the generation of hydroperoxides, their degradation and the formation of secondary oxidation products as investigated by FTIR, were lower in the treated oils. In conclusion, microwave pre-treatment prior to oil extraction reduced the oxidative degradation of oil samples, thereby increasing the storage stability of BCO.