Functional properties of raw and heat processed winged bean (Psophocarpus tetragonolobus) flour.

N solubility, emulsification capacity, foam capacity, fat and water absorption capacity of raw and heat-processed winged bean flour were compared with those of raw soy flour, both as a function of pH and NaCl concn. N solubility vs. pH profile showed only one min. at pH 4.5. Heat processing of winged bean flour lowered N solubility. Water and fat absorption capacity of winged bean flour were 2.1 and 1.4 g/g, resp.; those of raw soy flour were 3.1 and 1.2. Heat processing increased water and fat absorption capacity of winged bean flour by 38 and 57%, resp. Emulsification capacity of raw winged bean flour was higher than that of raw soy flour by about 30-60% depending on the pH. Heat processing diminished emulsification and foam capacity of winged bean flour by about 35 and 18%, resp. Incorporation of NaCl up to 0.4M improved emulsification capacity of winged bean flour and foam capacity up to 0.2M .