Volatile constituents of glutathione--ribose model system and its antioxidant activity.

Reaction between glutathione and ribose was carried out to study the volatiles formed via Maillard reaction and their antioxidant activity as well as their role in inhibition of LDL oxidation. The simultaneous distillation-extraction technique was used for trapping the volatile components followed by GC-MS analysis. Thirty six compounds were identified with the predominance of carbonyls and sulfur-containing compounds in the volatiles of this model system. Sensory evaluation was performed for the model system product according to the International Standard Methods (ISO). The results showed a high decrease in roasted and burnt attributes and remarkable increase in the like-boiled and roasted meat attributes. The sensory results of the model system product were confirmed by the presence of high concentrations of some volatile compounds having meat--like aroma such as 2-methyl-3-furanthiol and 2-furylmethanethiol. The radical scavenging activity of glutathione-ribose model system was quantified spectrophotometrically, using DPPH radical. The activity of the model system product was found to be slightly lower than that of gallic acid and BHA, but it was much higher than that of cinnamic acid (200 ppm. for each). A highly antioxidative activity was recorded by the model system product during the inhibition of LDL-oxidation in comparison with L-ascorbic acid as well as reduced glutathione (as a concentration of 0.5 micromol/L, for each) which may be due to the presence of some compounds such as 2-furylmethanethiol, 2-acetyl thiazole, 4-hydroxy-5-methyl-3(2H)-furanone.