Studies on products of browning reaction. Antioxidative activities of products of browning reaction prepared from glucosamine.

Abstract

Products of browning reaction of glucosamine were prepared from glucosamine-HCl by incubating it at 37°C for 0-30 days, and the antioxidative activity, reducing power, degree of browning, aminosugar contents, pH, moisture and total nitrogen contents of the products were measured. In addition, the brown products prepared from glucosamine by incubation at 37°C for 0, 15 and 30 days were fractionated by gel filtration using Sephadex G-15, and the antioxidative activity, reducing power, degree of browning and pH of each fraction were also measured. The results obtained were as follows: 1) When white powder of free glucosamine was allowed to stand for 3 days at 37°C, it transformed to a brown paste. 2) The strongest antioxidative activity was observed in the product obtained after incubation between 20 and 30 days. 3) The increase in antioxidative activity of the products of browning reaction was accompanied by the increase in the degree of browning. 4) The brown products prepared from glucosamine by long incubation were fractionated into fractions according to their molecular weights. Antioxidative activity was detected in the fractions corresponding to intermediate molecular weight.