ABSTRACT

Protein energy malnutrition and Vitamin A deficiency remains a major problem in Nigeria and Sub Saharan Africa. As a result, this study was aimed at developing acceptable and nutrient- dense biscuits using Vitamin A bio-fortified crop, Orange-fleshed sweet potatoes and locally underutilized crop, Bambara groundnut at different substitution levels with wheat flour. Biscuits were produced from composite flour blends obtained from Bambara groundnut (BGF) (Vigna subterranean L.verdc), Orange fleshed sweet potato (OFSPF) (Ipomoea batatas), and wheat flour (Triticum aestivum). In order to reduce the level of trans fatty acids in the biscuit, Sunflower oil was used to replace margarine. The resulting flour blends were analysed for functional and anti-nutritional properties while the biscuit samples were subjected to nutritional and sensory evaluations. The results were subjected to Statistical Analysis of Variance (ANOVA) and means were separated using the Duncan multiple range test and judged significant at 95% confidence level (P<0.05). The Protein, Fibre, Ash and Carbohydrate content of the biscuit samples were found to significantly (P<0.05) increase as the level of substitution with Bambara nut increased. On the other hand, there was a significant decrease in the Moisture and Fat content of the biscuit samples as the level of substitution with Bambara nut increased. The Provitamin A content of the samples was found to increase as OFSPF and BGF were included in the samples. However, Vitamin B3 content reduced significantly with increase in BGF substitution. The results obtained also showed that tannin and phytate content of the flour blends were in the range of 0.09 to 0.14mg/100g and 0.07 to 0.15mg/100g respectively. There were found to be within the acceptable limits for human consumption. The bulk density, oil absorption capacity, water absorption capacity, swelling index, foam capacity and foam stability of the flour blends were found to increase significantly when the level of Bambara nut was increased. The sensory attributes of the biscuits showed that biscuit samples from wheat flour (control) had the highest rating for all the attributes. However, biscuit samples made from wheat-OFSPF blends (W80-O20) and wheat- OFSPF and BGF (W60-O20-B20) compared favourably with the control sample with the later having the highest general acceptability score. Other biscuit samples were generally acceptable to the panel as they scored above 5 which is the minimum acceptable score in a 9 point hedonic scale. Generally, no sensory attribute contributed less than 50% to the general acceptability thus indicating that all attributes had a significant contribution to the general acceptability of the biscuit samples.