Process development, nutrition and sensory characteristics of spiced-smoked and sun-dried Dagaa ( Rastrineobola argentea) from Lake Victoria, Tanzania

Abstract

Dagaas (Rastrineobola argentea), also known as silver cyprinid, are tiny fishes (<9 g) found mostly in Lake Victoria, Nabugabo and Kyoga, and also in the River Nile. Dagaa is a very popular food in the Lake Victoria area and is used for formulating animal feeds due to their nutritional quality. The harvesting of dagaa is a demanding activity and the methods used include scoop net, seine net and catamaran or lift net. The harvesting of dagaa employs a lot of people who carry out the fishing and preservation and selling of the products. Dagaa product manufacturing is therefore considered to be a very important sector for job creation, income generation and food security. However, the traditional method of preserving dagaa, sun-drying (SDD), is often affected by heavy and prolonged rains in Tanzania. The present study was therefore undertaken to evaluate and compare the processing of spiced-smoked dagaa (SSD) and SDD; the year-round supply and marketing of these products were also compared. The results showed that SSD could be produced throughout the year; it showed a significantly (p<0.05) lower moisture content than SDD (1.81% vs. 2.4%). It also had an insignificant increase in fat content (14.9% vs. 14.1%) and a significantly higher ash content (17.3% vs. 15.7%). Dry matter content was insignificantly increased in SSD compared to SDD (98.2% vs. 97.6%). Crude protein was more or less unaffected in the two products (48.32% vs. 47.75%). Sensory evaluation results showed that SSD had significantly (p<0.05) higher scores in appearance (4.2 vs. 3.4), taste (4.1 vs. 3.15), flavour (4.5 vs. 3.2) and consumer preference or acceptability (4.47 vs. 3.63). Similar results were also shown by the consumers on the open market around the lake. Both products had no signs of dirt or filth. SSD was therefore considered to be superior. Despite SSD's good qualities, preference and availability, it could not match the sales volume of SDD on the local market due to its unfamiliarity and higher price.