Variation of Proximate Contents in Selected Marine Fish from Tanzanian Coast due to Seasonality and Processing Methods

The effect of seasonality (wet and dry seasons) and processing treatments (frying and boiling) on proximate composition of selected fish species (Alectis ciliaris, Lethrinus harak, Rastrelliger kanagurta and Siganus canaliculatus) from Tanzania marine waters were assessed. The proximate composition of fish was proved to be altered by the fish feeds, salinity, geographical location, seasons and processing methods. Therefore, the fish samples were purposively collected from four selected locations (Tanga, Bagamoyo, Dar es Salaam and Mtwara) and treated as appropriately. Proximate parameters were determined using AOAC standard methods. The proximate contents varied with changing seasons in all the fish species. Crude protein and lipid contents increased in wet season while moisture and ash contents increased in dry season. The effect of changing seasons in proximate contents was significant (p < 0.05) except in ash. Frying process had a significant effect (p < 0.05) on proximate contents in the fish species than boiling process except in ash. The derived model accurately predicted the extent of variation of proximate contents with both dry and wet seasons and processing treatment in particular frying. However, it failed to predict the extent of variation of lipid, crude protein and moisture with boiling treatment. Further research is needed to establish the extent of variations of proximate contents due to other processing methods such as steaming and microwaving.