• Winged bean seed;
  • soaking;
  • boiling;
  • water absorption;
  • leached solids;
  • water holding capacity;
  • swelling power


The effects of soaking small, medium and large seeds of Psophocarpus tetragonolobus (L) DC for up to 24h and then boiling the seeds for up to 30 min, or boiling the raw seeds for up to 120 min, were examined. Trends for hardness and water absorption of the beans were similar for all bean sizes. Soaking and/or boiling reduced the hardness of beans and increased the water absorption leached solids, water holding capacity and swelling power. Small beans were the hardest and showed the lowest level of the other characteristics. Medium sized beans were softer and had higher values of the above four parameters. Soaking for 24 h and then boiling for 30 min was more efficient in reducing the hardness of the beans than boiling for 2h. Linear regression showed high correlations among almost all the parameters measured.