Variations in Proximate Composition of Clupea harengus (Fillet & Skin, Head and Bones (SHB)) after Different Heat Treatment

Abstract

Clupea harengus is a table fish locally called sawa in south west Nigeria. It is among the freshwater fishes that are abundant and economically cheap. Present study assessed the effect of heat treatment on proximate composition and sensory qualities in the fillet and SHB (skin, head and bone) of Clupea harengus; using smoking (wood and coal) and poaching methods. Proximate analysis was done via standard analytical techniques and sensory evaluation of the processed fish was conducted by categorical ranking. All processing methods significantly (p<0.05) increased levels of protein and ash, but (p<0.05) reduced the fat and crude fibre contents in the fillet. Wood smoking of SHB recorded highest protein, ash and crude fiber contents of 55.65±4.20, 15.26± 0.53 and 13.40± 1.14 respectively. Highest protein concentration was obtained for wood & charcoal smoked in both fillet and SHB; but lowest in the poached fish (fillet and SHB). Moisture content was highest (72.07± 1.29%) in the poached SHB; but lowest in charcoal smoked fillet & SHB (44.01± 0.03 & 44.01± 0.00%) respectively. Wood and charcoal smoked fish samples were found most palatable by the panellists. Data obtained from this study demonstrated that processed fillet and SHB could be a veritable source of valuable ingredients for human consumption and animal feeds.

Keywords; Heat treatment; Clupea harengus; proximate; sensory evaluation, agricultural waste; discards