Evaluation of proximate and anti-nutritional composition of six different accessions of vigna subterranea (l.) verdc.

Abstract

Vigna subterranea L. Verdcis an annual seed crop widely favoured by resource-limited rural farmersin sub-Saharan Africa. The fresh seeds can be consumed raw or cooked or utilized to make different delicacies. The study evaluatedthenutritional and anti-nutritional content of seeds of sixdifferent accessions of V. subterraneato obtain information on their potential suitability as an alternative source of protein for humans and livestock. Seeds of each accession were ground to fine powder, sieved and labelled separately. Three replicates of each were then analysed for both proximate and anti-nutritional factors using standard methods. The results obtained were subjected to statistical analysis using one-way analysis of variance (ANOVA) and the results were expressed as mean ± standard deviation. The result showed that the sixaccessions are rich in protein (19.43±0.07%), crude fibre(4.38±0.23 %) and carbohydrate (55.59±2.52%) but also contained asubstantial amount of anti-nutritional factors such as oxalate (4.63±0.14 mg/g) and phytic acid (4.51±0.03 mg/g). TVSu 352, an accession originating from theUSA, had the highest protein (20.11%), high nitrogen-free extract (53.24%) and lowest fat (4.60%) content making it the most nutritious among the accessions studied, though it also contained the highest tannin (4.60 mg/g) level. TVSu 277 exhibited thelowest crude protein (18.91 %), lowest crude fibre (3.28 %), highest carbohydrate (57.43 %) and highest nitrogen-free extract (54.15 %). These showed that the accessions are quite rich, and exhibited diversity, in both proximate and anti-nutritional characteristics. It can be concluded that TVSu 352 is the most-nutritious among the accessions studied and can, therefore, be recommended for consumption or industrial utilization and widespread cultivation but further study is required to unravel its yield stability and resistance status. It can also be inferred that with adequate processing, the seeds of V. subterranea will be a good substitute for cowpea as an alternative source of protein in both humans and livestock because they are very rich in nutritional compounds.