Studies on yield, extracted leaf protein and deproteinised extract of winged bean grown as a biennial crop

The possible use of the long vegetative growing period of the winged bean, when grown as a biennial crop, as a source of extractable leaf protein was investigated in this study. The dry top yield of the crop during this period increased curvilinearly with time and followed the logistic growth law. A linear decrease with age was noted for the total and protein nitrogen extractability of this crop whereas the nitrogen percentage in dry matter of leaves and the extractable leaf protein yield gave a quadratic response. Unfractionated and heat fractionated proteins extracted from the leaves contained 61.9–85.3% protein, 4.6–12.8% fat, 0.2–4.6% ash, 0.5–2.7% crude fibre and 34.2–43.7 mg 100 g−1 β‐carotene on moisture free basis. The deproteinised juice, left after protein extraction, was also found to be ideally suited as a microbial growth medium for protein rich biomass production.