Development of Orange fleshed sweet potato and Bambara groundnut-based snacks for school children in Tanzania

Development of snacks using locally under-utilized crops such as orange fleshed sweet potatoes (OFSP) and Bambara groundnut is crucial for alleviating under-nutrition among primary school children through food-based approach. This study was aimed at developing an acceptable, shelf stable, nutrient dense snack from OFSP and Bambara groundnut. The 100% OFSP, 100% Bambara groundnuts and composite snacks at different levels of OFSP flour substitution were prepared and assessed for proximate composition, mineral and pro-vitamin A content, sensory properties, consumer acceptability and shelf life stability. The effect of extrusion on nutritional quality of the snacks was also assessed. The results showed that there were significant differences (p<0.05) in proximate composition between the developed snacks. Protein contents ranged from 4.08 ± 0.26 g/100g DM in 100% OFSP snacks to 15.03 ± 0.34 g/100g DM in 100% Bambara groundnut while pro-vitamin A ranged from 0.54 ± 0.05 mg/100g DM in 100% Bambara groundnut to 17.33 ± 0.48 mg/100g DM in 100% OFSP. Vitamin A retention after extrusion ranged between 59.08% (Bambara groundnut 100%) to 86.50% (OFSP_ 20%). The substitution of OFSP by Bambara groundnut in the formulation increased magnesium, phosphorous, potassium and iron and decreased calcium and sodium contents in the composite snacks. OFSP based snacks had higher mean acceptability scores (6.62 – 7.0) than the 100% Bambara groundnuts based snack (5.88) with orange colour and sweetness being the drivers for consumer liking of the snacks. Predicted shelf life at room temperature ranging between 118 – 150 days. The study showed that development of OFSP substituted with Bambara groundnut up to 40% enhances nutritional quality of the products, retains sensory properties and is acceptable by consumers with colour and sweetness being the main drivers for their liking.