Chemical and physical characteristics of five Nigerian 440 varieties of fresh green immature soybean (Glycine max (L.) Merrill)

Purpose - The study aims to investigate the potential of green immature soybean among Nigeria soybean varieties as human food. Design/methodology/approach - Five Nigeria soybean varieties were harvested at 90 days old. The fresh green immature soybean seed were evaluated for chemical composition, physical and sensory characteristics. The physical characteristics looked into seed size (breadth and length), weight, seed colour, hull thickness and percentage of hydration. The chemical composition was compared to mature soybean seeds while the sensory attributes were compared to fresh green peas. Findings - The raw mature soybean (RMS) was significantly higher and lower in chemical composition and anti-nutritional factors respectively. The highest moisture content ranges from 62.8 per cent in TGX 1019-2(EB) to 65.4 per cent in TGX 1485-1(D). The protein content (15.3 per cent) was highest in TGX1485-1(D) and lowest value in TGX1448-2(E). The level of tannin was significantly higher in TGX1448-2(E) and 923-2(E) while trypsin inhibitor was significantly (p < 0.05) higher in TGX1440-1(E) and TGX1485-1(D). TGX1485-1(D) had superior physical characteristics to other immature varieties with significant (p < 0.05) higher value for breadth, length and height. The hull thickness of the seeds was within 0.01 to 0.05 and the percentage of hydration ranges within 5.5 to 6.8 per cent. All varieties had a green colour for the seed coat. Overall sensory acceptability of TGX TGX1440-1(E), 1485-1(D) and 1019-2(EB) compared favourably well with green peas used as control for sensory evaluation. Originality/value - This study could help to identify the potential of some Nigerian soybean cultivars for production for use as a source of vegetable in the diet and also provided valuable information for further improvement of soybean for food uses.