Effect of Storage on the Nutritional Composition and Mycoflora of Sphenostylis stenocarpa Stored for Twenty Weeks

Abstract

The nutritional and mycoflora changes in dried African yam beans (Sphenostylis stenocarpa) were investigated during a storage period of twenty weeks. The result of the proximate analysis (g/100 g) showed that the following moisture content decreased from 11.15-9.80, fat 1.25-0.49, crude fibre 6.18-2.64, crude protein 77.92-62.14 while the ash content increased from 3.20-3.78, carbohydrate content 0.36-18.32. The mineral analysis (mg/100 g) showed a decrease in all parameters investigated, sodium (Na) 2.57-1.35, potassium (K) 42.26-31.75, calcium (Ca) 21.45-12.56, magnesium (Mg) 27.75-20.72, iron (Fe) 0.25-0.12, zinc (Zn) 0.06-0.05, copper (Cu) 0.03-0.03, phosphorus (P) 32.08-22.03, manganese (Mn) 0.11-0.06, chromium (Cr) 0.002-0.001. Lead (Pb), cadmium (Cd) and nickel (Ni) were not detected. Five fungi comprising four genera were isolated using direct plating, washing and dilution methods on Potato Dextrose Agar (PDA), and identified using their cultural and morphological features with reference to standard procedures. The fungi isolated were Aspergillus niger, Aspergillus flavus, Penicillium sp., Mucor sp. and Phytophthora palmivora. It can be concluded that storage encourages proliferation of mycoflora thereby leading to reduction in the nutritional and mineral composition of the stored sample.