Nutritive value of sun dried and traditionally smoked oreochromis shiranus (boulenger, 1897) raised in earthen ponds

Abstract

Oreochromis shiranus (Boulenger, 1897) is a strain of tilapia found in the Shire River (Malawi) and it is the commonest of the tilapia species raised by farmers in Malawi due to amongst many reasons, its ease of management and the ability to breed in captivity. Immediately after harvest from ponds, the fish are usually sold fresh. The need for consuming processed food products is however, rapidly gaining popularity among people with the knowledge that processed products are handy, nutritious and display a long shelf life. For nutritionists, it is also important to remember that processing also alters nutrient composition of food especially methods that involve use of heat. In this study, nutritional composition (moisture content, crude protein, crude fat and ash) of traditionally smoked and sun dried pond raised Oreochromis shiranus was analyzed. Sun dried fish had significantly (P<0.05) higher crude protein (62.43±0.50), ash (17.44±0.26) and crude fat (19.15±0.47) than smoked fish except for moisture (P>0.05). Apart from the high ash content in sun dried fish, nutrient content of the processed fish (smoked and sun dried) was significantly lower (P<0.05) than in fresh fish. Fish provides the highest source of dietary animal protein to many people in Malawi including those with low incomes who cannot afford other protein sources such as beef. The study provides empirical evidence to suggest that more nutrients can be obtained in sun dried Oreochromis shiranus hence recommending its use. Further, lower moisture content in sun dried fish may entail a product with qualities of a longer shelf life (storage) since moisture provides favourable environment for rapid microbial growth