The effect of pomegranate peel extract (PPE) on the polyphenol oxidase (PPO) and quality of Pacific white shrimp (Litopenaeus vannamei) during refrigerated storage

•Pomegranate peel extract can serve as antioxidant and antibacterial agent of shrimp.•Pomegranate peel extract of shrimp-alternative to sodium metabisulfite, is suggested.•Pomegranate peel extract could reduce the melanosis of cold stored shrimp.•Pomegranate peel extract could inhibit polyphenol oxidase of shrimp.

The effect of pomegranate peel extract (PPE) (methanolic) on the enzyme polyphenol oxidase (PPO) activity and quality of Pacific white shrimp (Litopenaeus vannamei) during refrigerated storage of 10 days was investigated. The inhibitory activity of PPE toward the PPO of shrimp appeared to follow a dose-dependent manner. With storage, treating the shrimp with either 1 g/100 mL or 2 g/100 mL PE solution could appreciably retard the mesophilic, psychrophilic, lactic acid bacteria (LAB) and enterobacteriaceae counts (P < 0.05). With storage also, treating the shrimp with PE solution at both levels could significantly decrease the total volatile basic nitrogen (TVB-N), trimethylamine (TMA) and thiobarbituric acid (TBA) (P < 0.05). By day 6, PPE-treated shrimp obtained lower melanosis score but by day 10, odor, texture, color as well as overall likeness received higher sensory scores. Hence, the PPE could serve as a preservative method as well as melanosis inhibitor of shrimp and could substitute for sodium metabisulphite.