Effect of Processing Methods on Qualities of Bambara Groundnut ( Voandzeia subterranea (L.) Thouars) Flour and their Acceptability in Extruded Snacks

摘要

This study evaluated the effects of either germination, roasting or germination-roasting of Bambara groundnut (BGN) seeds prior to milling into flour, on their chemical composition and determined acceptability of the flour samples in extruded snacks.The flour samples were mixed with equal proportion of other ingredients such as acha (Digitaria exile Staff), carrot, sugar, fat and spices and extruded using a single screw Brabender laboratory extruder at 150°C, 170 rpm screw speed and 20% feed moisture content. The extrudates were cooled and subjected to proximate, anti-nutrient, functional and sensory analyses using standard methods. Data generated was subjected to one way analysis of variance using SPSS version 17, while means were separated usingDuncan's new multiple range test and significance was accepted at p = 0.05. Result of proximate analysis revealed that the protein contents of roasted (23.09%) and germinated-roasted (23.20%) flours were significantly (p<0.05) higher than those of othersamples. The samples differed significantly (p<0.05) in their trypsin inhibitor, tannic acid, phytate and haemagglutinnin activities. Roasting process reduced concentration of trypsin inhibitor by 37.5%, germination reduced it by 17%, while a combination of germination and roasting caused highest reduction (68%). There were significant (p<0.05) differences in Water Binding Capacity (WBC), Foaming Capacity (FC) and Nitrogen Solubility (NS) of the samples. Roasting BGN flour yielded extruded snack with improved taste, aroma/flavor and overall acceptability. Acceptable snacks of adequate nutritional and anti-nutritional qualities were produced by roasting or/and germination of BGN seeds prior to extrusion cooking of their flour with other ingredients. Bambara groundnut should be exploited in combating protein-energy malnutrition prevalent in Nigeria and other African countries.