Enhancement the Stability, Quality and Functional Properties of Rapeseed Oil by Mixing with Non-conventional Oils
Objective: The main target of this study was to raise stability, quality and functional properties of rapeseed oil by mixing with non-conventional oils, namely apricot kernels, grape seed, tomato seed and wheat germ containing high levels of phytonutrients. Methodology: These components such as tocopherols, tocotrienols and phytosterols as well as fatty acid composition were determined by HPLC and GLC. Rancimat was used for detecting oxidative stability. Results: Admix rapeseed oil (95, 90 and 80% v/v) with four non-conventional oils resulted in a decrease in the ratio of polyunsaturated/saturated fatty acids which have a positive influence on oxidative stability. The ratio of omega-6 to omega-3 in mixed oils was attained to desirable ratios having positive effects in decrease the risk of some diseases. Oxidative stability of rapeseed oil blended with wheat germ oil was highest. The amount of β-sitosterol was increased by increasing the ratios of non-conventional oils. Adding wheat germ oil to rapeseed oil leads to an increase in total tocopherols and α-tocopherol. Conclusion: Admixed rapeseed oil with non-conventional oil at a level of 20% v/v is more satisfactory and superior to other blends in terms of stability which is an important indicator the oil quality and shelf life of edible oils.