Efficacy of Edible Coatings on Enhancing the Shelf-Life of Fresh and Frozen Tilapia (Oreochromis niloticus) Fish

Abstract

Tilapia (Oreochromis niloticus) is generally processed to fresh and frozen fillets for domestic consumption. Deterioration of fish quality in refrigerator storage has great impact on the nutritious value of fish and the health of consumers. Freezing and cold storage is an efficient method which preserves taste and nutritional value. Glazing is a process used to reduce undesirable drying or dehydration of fish during frozen or cold storage. Objective of the current research studied the feasibility of edible coating in maintaing and preserving the chemical, microbial and sensory attributes of fresh and frozen tilapia fillet. The fresh and frozen tilapia fillets were treated with different formulas (N₀: control; N₁: 1.5% w/w chitosan and peracetic acid; N₂: 1.5% w/w chitosan and gelatin; N₃: 1.5% w/w whey protein isolate and ethanol; N₄: 1.5% w/w xanthan gum). The chemical quality was based on the analyzed results of ammonia (µNH₃/g) and pH; biogenic amines such as putrescine (mg/kg), cadaverine (mg/kg), histamine (mg/kg), spermine (mg/kg), spermidine (mg/kg); lipid oxidation or malondialdehyde value (mg/kg); microorganism such as Total plate count (cfu/g), Enterobacteriaceae (cfu/g), Coliform (cfu/g), E. coli (cfu/g), Staphylococus (cfu/g), Listeria (cfu/g), Salmonella (cfu/g), Vibrio (cfu/g); sensory score. All treated fresh tilapia fillets were tested after 21 days of cool storage (4^oC). All treated frozen tilapia fillets were tested after 12 months of cold storage (-18^oC). Results revealed that the incorporation of 1.5% w/w chitosan and peracetic acid could inhibit microbial spoilage and lipid oxidation and therefore maintain the freshness of tilapia fillet for 21 days at 4^oC and 12 months at -18^oC storage. The study indicated that the combination treatment with edible coating could be commercially utilized to maintain the freshness and prolong the shelfâ€life of fresh and frozen tilapia fillet effectively.

Keywords: Frozen, Tilapia fillet, Chitosan, Peractic acid, Gelatin, Whey protein isolate, Ethanol, Xanthan gum.