Abstract:
Cleaned Bambara groundnut seeds were divided into four lots. Each lot was separately pretreated thus: germinated, roasted, germinated and roasted, and unprocessed which served as control. Each sample was ground, sieved, and extruded using single screw extruder. Consumer preference test was done by a taste panel of 50 people who rated the products on the attributes of colour, taste, flavour and overall acceptability using a 9-point hedonic scale. The treatment (roasting) given on the most preferred product was adopted in producing composite of bambara and “acha” flour, which was mixed with graded levels of carrot and other ingredients, and extruded. The product samples were subjected to analyses for chemical composition, residual anti-nutrients, physico-chemical and sensory properties using standard methods. The samples were stored for six months under ambient conditions (28±2ºC) and analysed at 2 months interval for moisture, texture, provitamin A (b-carotene) and sensory properties. Extruded snacks from the composite of bambara groundnut, hungry rice and carrot had high protein (15-16%), b-carotene (180-550.13mg/100g retinol) and minerals (iron and zinc) contents. Inclusion of carrot to the composite increased (p£0.05) the b-carotene content of the product, when compared with the control. There were no significant differences (p>0.05) between the sensory qualities of the control and products with 5% to 15% carrot. Extrusion cooking significantly (p<0.05) reduced moisture content and brought about concentration of other proximate components. It also significantly (p£0.05) reduced phytate from 91.01-81.11mg/100g to 36.75-30.58mg/100g, tannin from 0.16mg-0.26/100g to 0.06-0.09mg/100g. Trypsin inhibitor and haemagglutinin activities were reduced from 6.81-8.32mg/100g and 4.01-6.50Hu/mg protein, respectively, to undetectable levels. Extrusion cooking improved protein digestibility of the snacks. b-carotene and minerals were not significantly (p>0.05) affected by the extrusion cooking, while there was a significant reduction (p<0.05) of vitamin C from 6.21-8.96mg/100g to 2.51-4.05mg/100g in the extruded snacks. Significant (p<0.05) reductions were observed in vitamin B1(40-50%), B2(15-24%), B3(15-24%) and B6(25-30%) content of the extruded snacks. Storage for six months did not adversely influence the sensory characteristics of the developed snacks. It is evident from the composition of the developed products that protein-energy malnutrition and micronutrient deficiency problems can be averted through dietary diversification and extrusion cooking technology.
