Abstract
The oxidation of edible oils leads to the production of undesirable odors and harmful substances. Therefore, the oxidation inhibition is crucial. The inhibitory effect of conventional lipid-soluble antioxidants on the oxidation of functional oils such as flaxseed oil, rich in polyunsaturated fatty acids (PUFA), is not so high. In this study, polyethylenimine (PEI) containing amine groups which can regenerate vitamin E (VEH) was introduced as a novel, odorless, insoluble antioxidant. PEI's insolubility in oil minimized its contribution to oxidation promotion, unlike lipid-soluble antioxidants. Experimental results demonstrated that PEI showed a synergist effect on oxidation inhibition with added VEH particularly in a VEH-added lipid model by regenerating VEH. When applied to flaxseed oil, PEI outperformed other antioxidant systems by acting in concert with original VEH contained in PEI. Consequently, the addition of insoluble PEI to oils can become an effective method for protection against PUFA oxidation in oils, although the inhibition of PUFA oxidation in oils has been thought to be difficult up to now.
