Evaluation of probiotic carboxymethyl cellulose-sodium caseinate films and their application in extending shelf life quality of fresh trout fillets

An increasing interest has risen on the development of active food packaging to improve freshness and avoid external contamination of seafood commodities. The aims of the present study were to fabricate carboxymethyl cellulose-sodium caseinate films containing Lactobacillus acidophilus, L. reuteri, L. casei, L. rhamnosus, and Bifidobacterium bifidum, and evaluate their application on quality properties of raw trout fillets during refrigerated storage for 14 days. The physicochemical, mechanical, structural, and morphology properties of designated films were evaluated using standard procedures. The refrigerated fillets were examined for microbial (Enterobacteriaceae, lactic acid bacteria, total viable count, and psychrotrophic bacteria) and chemical (protein carbonyl, total volatile base nitrogen, peroxide value, thiobarbituric acid reactive substances, and biogenic amine formation) properties. There was a negative correlation between the probiotic's viability and storage time (P < 0.05). The probiotic films provoked retardation of microbial growth of fillets compared to the control at the end of storage period. Chemical changes in all treated fillets were significantly lower than untreated group during the study (P < 0.05). It could be concluded that probiotic films could extend shelf life of trout fillets at least two weeks, at the same time, it could be a method to incorporate beneficial probiotic bacteria to the trout fish.