Active products of browning reaction formed in irradiated fructose solution

Irradiated D-fructose solution exhibited marked enhancement in browning reaction with amino acid, and this effect depended on some radiolytic products of fructose. The radiolytic products formed in solution under aerated and anaerobic conditions were fractionated by column chromatography on Sephadex G-10, LH-20 and ion-exchange resin and by TLC on silica gel. The browning activity of each fraction was determined by reaction with glycine. The browning active products in the fraction were identified by GLC, GC-MS and TLC; they were: 6-deoxy-D-threo-2,5-hexodiulose, D-threo-2,5-hexodiulose, D-arabino-hexosulose and 4-deoxy-L-glycero-2,5-hexodiulose from irradiated solution under anaerobic conditions and D-threo-2,5-hexodiulose and D-arabinohexosulose from solution under aerated conditions. The browning reactions of the model compounds with glycine also indicated that D-threo-2,5-hexodiulose and 6-deoxy-D-threo-2,5-hexodiulose were more active than D-arabinohexosulose and 3-deoxy-D-erythrohexosulose. (author)