Abstract:Metapenaeus ensis was used as the material to study the inhibitory effect of reduced glutathione (GSH) on polyphenol oxidase (PPO) activity, with optimal inhibitory effect on PPO activity determined at a GSH concentration of 4 g/L and a treatment time of 30 min. PPO activity, total volatile basic nitrogen (TVB-N) content, whiteness, salt-soluble muscle protein, and sensory evaluation were used as indicators to study the effect of different reduced GSH-composite preservatives on the quality of M. ensis during frozen storage at -18 ℃. Our results showed that 4 g/L GSH effectively inhibited PPO activity and decreased melanin accumulation. The preservatives prepared from 4 g/L GSH+10 g/L sorbitol and 4 g/L GSH+5 g/L citric acid reduced the generation of TVB-N and decreased the degradation rate of salt-soluble protein during storage. Shrimp treated with the preservative composed of 4 g/L GSH+10 g/L sorbitol+5 g/L citric acid possessed the highest sensory evaluation score. These findings suggested that the preservative composed of 4 g/L GSH+10 g/L sorbitol+5 g/L citric acid exhibited the best fresh-keeping effect for the storage of M. ensis.
