Quality deterioration of winged bean during storage.

Seeds of winged bean (Psophocarpus tetragonolobus) were stored under four different sets of conditions; 65% relative humidity (RH) at 5 degrees C, 35% RH at 37 degrees C, 65% RH at 37 degrees C, and 85% RH at 37 degrees C. After storage for three and five months, samples were taken out to explore quality changes during storage. The germination capacity decreased during storage at high temperatures. Although little change was found in content in extractable oil, a decrease in the iodine value and an increase in the acid value and in the TBA value were significant during storage at high temperature and high moisture, indicating deterioration of oil. Aldehyde in defatted bean extract increased under all conditions for storage. Protein extractability was greatly reduced at 36 degrees C and 85% RH, while no reduction was observed at other conditions.