The effect of pre-treatments on the proximate composition and microbial quality of smocked Nangnang fish (Brycinus Nurse)

Abstract

Nangnang fish (Brycinus Nurse) is one of the pelagic fishes caught in Uganda. It is mostly a delicacy among the Alur people of the West-Nile region in Uganda making it one of their major cheap sources of proteins. To preserve and add value to Nangnang fish, it is usually fried, salted, sundried and smoked. This study investigated the effect of Pre-treatments (Brining and Blanching) before smoking at 75ºc on the proximate composition and microbial quality of smoked Nangnang fish. Raw fish was the control for all the samples whereas Fresh smoked was the control for the pre-treated smoked fish (brined and blanched). Results of proximate analysis for the four samples showed a significant difference (p> 0.05). Ash, protein and Crude fat increased with an increase in smoking time. This is because as more moisture content was lost by evaporation due to smoking, proximate components become concentrated per unit weight expressed as a percentage of the whole sample weight. However, freshly smoked fish had an averagely more proximate composition, an indication that some nutrients were lost due to the effects of the pre-treatments on the fish. Freshly smoked had means of 7.67%, 25.00%, 39.00% for Ash, crude fat, and Crude protein respectively as compared to 6.67%, 23.00%, 36.67% for brined smoked fish and 7.00%, 18.00%, 33.33% for blanched fish. Carbohydrates were less than 1% in all the fish samples. On the other hand, the overall microbial quality was least detected in brined fish and highest in fresh fish as compared to blanched fish. This trend was also observed in raw fish subjected to pretreatments before smoking, no yeast and moulds were detected in smoked fish.