Effect of handling treatment on fillet yields and quality of tropical fish

Abstract

The effect on fillet yields and quality of the cold shock reaction of tropical fish when they are iced immediately following death was investigated. Tilapia (Oreochromis moss‐ambicus/niloticus hybrid) were subjected to three handling treatments: filleting immediately following death; icing the whole fish immediately following death and filleting after 3 days; ageing the fish for 6 hr at ambient temperature prior to icing and then filleting after 3 days. All fillets were stored on ice until 9 days after death. Pre‐rigor filleting resulted in the highest filleting yields with the least drip loss and gaping on storage but the shortest shelf life. This was accompanied by the highest post‐mortem metabolic rate. The lowest yields and highest drip loss were obtained by icing the fish immediately at death followed by filleting after 3 days. A 6‐hr delay before icing gave yields and drip loss which were between these two extremes and also the slowest post‐mortem metabolism. The two post‐rigor filleting procedures produced fillets with increased gaping but a longer shelf life compared with pre‐rigor filleting. The implications of the cold shock reaction in terms of recommended codes of practice and handling operations in tropical fisheries are discussed.