Chitosan-based Edible Coatings for Quality Preservation of Postharvest Whiteleg Shrimp (Litopenaeus vannamei)

Postharvest shrimp is highly susceptible to both microbiological spoilage and endogenous enzymatic browning, so it should be preserved properly using effective and appropriate methods. The effects of 1.0% and 1.5% O-carboxymethyl chitosan (CMC) and 1.0% and 1.5% chitosan (CH) coatings on the quality changes of whiteleg shrimp (Litopenaeus vannamei) during refrigerated storage (0 +/- 1 degrees C) of 10 d were investigated. The pretreatment with CMC and CH solution (1.0% or 1.5%) retarded growth of psychrophilic bacteria throughout storage in comparison with the control (P < 0.05). The lower increases in pH and total volatile base (TVB) content were obtained in the shrimp treated with CMC and CH solution at both levels, compared with the control samples (P < 0.05). Loss in freshness and melanosis decreased after the shrimp was treated with CMC and CH. In addition, CMC and CH (1.0% or 1.5%) showed inhibitory activity toward total viable bacteria counts of white shrimp in a dose-dependent manner. Therefore, chitosan and O-carboxymethyl chitosan can be used as promising melanosis inhibitors as well as antimicrobial agents during refrigerated storage.