Antioxidant Effects of Wheat Gliadin and Hen’s Egg White in Powder Model Systems: Protection against Oxidative Deterioration of Safflower Oil and Sardine Oil

Abstract

The antioxidant effects of various food proteins such as gluten, casein, gelatin, gliadin and egg white were examined in powder model systems of these proteins simply mixed with safflower oil or sardine oil under a moderate environment (37°C, RH = 30~50%). Both the peroxide and TBA values in the mixture of gliadin and safflower oil or sardine oil were maintained at marginal levels throughout the experimental period. After indicated periods, the amounts of oil (triglyceride) and its constituent ‘PUFA’ were measured by thin-layer and gas chromatographic means, respectively. As a result, the two kinds of oils were found left almost intact in their corresponding mixtures. Although egg white was somewhat inferior to gliadin in the preservability of safflower oil at stages exceeding a period of 4 weeks, similar effectiveness was observed for the mixtures of this protein and oils. The other proteins were not so effective as gliadin or egg white in protecting these edible oils against oxidative damage. It thus may safely be said that the high antioxidant effect of gliadin or egg white can be elicited not only upon free PUFA but also upon edible oils rich in PUFA.