Nutrient composition of solar dried and traditionally smoked Oreochromis mossambicus (Peters, 1852)

Abstract

Fish is a highly nutritious food in Malawi providing the most affordable dietary animal protein. In the lower Shire valley area of the country, the commonest consumed fish species is Oreochromis mossambicus (Mozambique Tilapia) which is usually smoked before marketing and/or consumption. Recently, the solar tent drying method has been introduced in the area as an environmentally smart technology to reduce dependency on use of fuel wood for processing fish as well as reducing problems faced during rainy season. However, processing affects nutrient value of foods underpinning the importance of consumer knowledge regarding proximate profiles in food to ensure that these are within the range of dietary requirement. This study determined the nutrient composition (protein, fat, ash and moisture; minerals – calcium, iron and magnesium) of Oreochromis mossambicus processed in a solar drier and traditionally smoked. Protein content was 50.62%, 61.26% and 54.79%; while crude fat was 5.91%, 13.43% and 8.90% respectively for fresh, solar dried and traditionally smoked fish. Determined moisture content was 91.97%, 15.90% and 24.54% in fresh, solar dried and traditionally smoked fish respectively, with significant differences between treatments (P<0.05). Ash content was also significantly different (P<0.05) between treatments - 11.12% (fresh), 17.58% (solar dried) and 14.72% (traditionally smoked). Mineral contents did not show any significant differences (P>0.05). It is concluded that fish processed in the solar drier are more nutritious and with a longer storage period than traditionally smoked fish. The lower Shire valley is the hottest area in Malawi hence use of solar drier could be an efficient, affordable and sustainable method of processing fresh fish.