Influence of chitosan-gelatin edible coating incorporated with longkong pericarp extract on refrigerated black tiger Shrimp (Penaeus monodon)

Chitosan-Gelatin (CHI-Gel) based edible coating incorporated with longkong pericarp extract (LPE) was developed and investigated for its impact on the quality of black tiger shrimp (Penaeus monodon) during refrigerated storage (4 ​°C) for 20 days. Shrimp coated with CHI-Gel-LPE (1.5%) had better quality indices than control (no coating), those coated with CHI, CHI-Gel, and CHI-Gel-LPE at lower concentrations (0.5 and 1%). The CHI-Gel-LPE inhibited melanosis and polyphenol oxidase (PPO) and controlled the pH changes in a dose-dependent manner. Lipid oxidation indices such as TBARS, PV, p-anisidine, and totox values were significantly controlled by the treatments throughout the storage. The CHI-GEL-LPE-1.5% coated sample had the lowest protein oxidation, and it's ascertained by the lowest loss of sulfhydryl groups, with the lowest carbonyl content throughout the storage (P ​< ​0.05). CHI-Gel-LPE (0.5–1.5%) coated samples had the lowest microbial growth (total viable count, lactic acid bacteria, Enterobacteriaceae, and Psychrotrophic bacteria) relative to the other treatments. Efficacy in quality maintenance of shrimp by LPE incorporated coating was improved with augmenting concentration used. Overall, LPE in the CHI-Gel edible coating served as a natural antioxidant, with antimicrobial activity and inhibiting melanosis, thus retain the quality and extend the shelf-life of shrimp stored at a refrigerated temperature.