Effects of processing method on proximate composition of gutted fresh Mcheni (Rhamphochromis species) (Piscies: Cichlidae) from Lake Malawi.

Abstract

The effect of sun drying, smoking, salting and combination of these processing methods on proximate composition of fresh gutted Rhamphochromis fish from Lake Malawi were investigated against whole fish as a control. Fresh whole fish had 57.24 ± 4.57%, 49.5 ± 0.18%, 35.8 ± 0.02%, 11.9 ± 0.04% and 25.6 ± 0.41% for mean moisture, crude protein, crude fat, ash and energy, respectively. Fish that were salted then later sun dried had significantly high mean moisture content (16.7 ± 0.24%) while lowest mean moisture content (9.6 ± 0.16%) was obtained in smoked fish (P<0.05). Smoked fish also retained more crude protein (45.2 ± 0.05%) while fish that were salted then sun dried had highest mean loss in crude protein (34.1 ± 0.07%) (P<0.05). Highest and lowest mean crude fat was obtained in sun dried fish (34.9±0.02%) and salted then sundried (25.8 ± 0.16%) fish respectively (P<0.05). Fish that were salted then smoked had highest mean ash value (20.4 ± 0.23%) while lowest mean values (11.4 ± 0.15%) were recorded in sun dried then smoked fish (P<0.05). Smoked fish had higher mean energy levels (23.2 ± 0.04%) while fish that were salted then sundried had lowest mean energy levels (20.1 ± 0.12%) (P<0.05). The general observation was that smoking fish increases protein retention while addition of salt result into loss of protein and fat. Furthermore, smoked fish had lowest moisture content and average fat levels suggesting a longer shelf life. This study recommends smoking as a way to obtaining maximum nutritional quality as well as longer storable product.amongst four species of seaweed.