PHYTIC ACID HYDROLYSIS AND BEAN SUSCEPTIBILITY TO STORAGE INDUCED HARDENING

Abstract
Two bean cultivars were stored over a 33-day period (75% RH and 41°C). After this period, cooked hardness, levels of phytate, phytase activity and integrity of protein bodies were monitored. The Michigan cultivar, which was the most susceptible to hardening, showed higher initial content of phytate which decreased by 20.7% after 30 days of storage. In contrast, Ojo de cabra, the cultivar less susceptible to hardening, presented lower initial content of phytate and a marked drop of 66.1% in its level during the same period of time. The phytase activity and the autolytic protein body destruction were higher in the last one than those in the former one. These results suggest that the contents of phytate or its rate of hydrolysis are not the major contributor to the seed susceptibility to storage induced hardening of different bean varieties.