Isolation and physicochemical properties of starch from winged bean (Psophocarpus tetragonolobus).

The preparation and physico-chemical properties of starch from winged bean seeds were studied. Tabulated results showed gelatinization temp. of 61-65.5-70 degree C, with single stage swelling and low solubility (from 0.20% at 30 degree C to 15.40 at 100 degree C), swelling power 3.35% at 30 degree C and 18.50 at 100 degree C, with extensive solubility in dimethylsulphoxide (about 80% in 35 h) possibly due to heterogeneous bonding forces within the granule. The starch was non-ionic, with an amylose content of 38.5%. Glucoamylase hydrolysed native starch by 79.8%, gelatinized starch by 98.6% in 60 h at 37 degree C; salivary alpha-amylase hydrolysed native starch by 14.8%, gelatinized starch by 40.5% in 100 h at 37 degree C. (1.0 and 36.0% resp. in 10 h, or 0.70 and 30.0 in 1 h).