Proximate composition of Oreochromis niloticus subjected to different preservation methods

Twenty one (21) specimens of Oreochromis niloticus (total weight 400g) were collected from a market in Enugu metropolis and used to assess the effects of different preservation methods on proximate composition. The fish samples were stored for 28 days. Preservation and processing methods adopted were: refrigeration, deep-freezing, oven-drying, straight-smoking and salted smoking. The oven-dried, straight-smoked, and salted-smoked samples were stored in polythene bags at room temperature in the laboratory. Moisture, protein, fat, fiber and ash contents of all the sample were determined according to the Association of Official Analytical Chemists procedures. Free preservation on storage led to significant decrease (P<0.05) in the percentage ash, crude protein and fat contents of fish samples. The greatest reduction was observed in refrigerated samples while salted-smoked samples were the least affected. There was a significant difference (P<0.05) between the storage period and the free-fatty acid of the samples. The refrigerated samples showed the highest levels of rancidity while the salted-smoked method gave the highest level of stabilizing in the proximate composition on storage for 28 days.Keywords: Oreochromis niloticus, Preservation methods, Proximate statusAnimal Research International (2012) 9(3): 1619 – 162