Production, physicochemical and sensory characterization of sweet potato–bambara groundnut mixed semolina (dackere) as affected by germination and fermentation using Lactobacillus plantarum

Abstract

Dackere is a granular food which is usually consumed with or without curdled milk. It can be produced from either cereals or tuber flours including corn, cassava, millet, sweet potato. However, dackere is poor in proteins. This work is aimed at evaluating the nutritional and sensory properties of dackere made from sweet potatoes and bambara groundnuts blended flour and the effect of the seeds treatments such as germination and fermentation. Results revealed significant effects of blending, germination of bambara seeds and fermentation of the blend on the properties of the dackeres. In this respect, 50 % substitution induced an increase in protein content from 5.7 % in sweet potato dackere to 12.1 % in sweet potato–bambara dackere blend. Similarly the ash and fat content increased from 1.2 and 1.4 %, respectively to 2.4 and 4.2 %. While germination affected only the reducing sugar level which increased, fermentation of the blend induced a significant increase in the proteins and reducing sugars. Blending with bambara groundnut also affected the functional properties such as the decrease in water and oil absorption capacities, the peak, set back and final viscosities, and the increase in least gelation concentration. The functional properties also varied significantly with germination and fermentation. In particular, the peak, set back and final viscosities decreased with fermentation while the ability to absorb water increased. The most accepted dackere was fermented ungerminated-sweet potato blend which exhibited a lighter colour.