Abstract
Various amino or nitrogen compounds were reacted with various reducing sugars in aqueous solutions of each 2 M concentration under the condition at 100°C for 5 hr and at initial pH ca. 6. 5. The resulting brown solutions were dialyzed and the inner solution was freeze-dried. All these nondialyzable browning reaction products showed inhibitory effects against autoxidation of 40% ethanol solution of fatty acids. Of these, the products obtained from D-glucose and L-arginine, L-histidine or L-cysteine had a stronger antioxidant activity. The product from guanidine and D-glucose reacted at initial pH 12 showed a very strong activity. When the initial pH of the browning reaction was higher, and also when the concentration ratio of glycine was higher than that of D-xylose in the reaction between glycine and xylose, the nondialyzable brown products obtained showed stronger antioxidant activity and gave higher nitrogen contents, indicating correlationship between the activity and the nitrogen content. In the present work, as substrate of autoxidation were used a mixture of fatty acids, purified linoleic acid and linolenic acid, and it was assumed that the activity was affected largely by the purity of the substrate.
