INCREASING THE SHELF-LIFE TROUT FILLETS BY SODIUM CASEINATE-PERSIAN GUM BIOCOMPOSITE FILM INCORPORATED WITH GINGER EXTRACT

Abstract

The effects of sodium caseinate (SC)-Persian gum (PG) films enriched with Zingiber officinale extract (ZOE) were investigated on the quality of rainbow trout over a 16 day at 4°C. The trout filets were divided to 4 groups as uncoated, coated with SC-PG, SC-PG-1% ZOE and SC-PG-1.5% ZOE. Sensorial, chemical and microbial characteristics of trout samples were evaluated on 0, 4, 8, 12 and 16 days of storage. GC-MS analysis exhibited that ZOE is rich in phenolic compounds including zingiberene and cis-6-shogaol. Active films embedded with 1.5% of ZOE revealed a remarkable decline in bacterial growth over the storage time. Wrapping with SC-PG-1.5%ZOE composite film tended to delay the elevation of thiobarbituric acid and peroxide value. Samples containing 1.5% ZOE were mostly preferred by sensory panelists. Based on the results of the present study, the edible films were suitable candidates for preserving quality properties and extending the shelf life of rainbow trout fillets.