The Use of Phytate-Degrading Enzyme Extracted From Germinated Legumes in Food Processing

The aim of this study was an attempt to use phytase enzyme extracted from plant sources such as germinated legumes to reduce phytic acid content in faba bean, lentil, pea, chickpea and kidney bean during soaking and germination processes. Legume seeds are a good source of phosphorus compounds. Phytic acid contents in raw legume seeds such as faba bean, lentil, pea, chickpea and kidney bean were 1.10, 0.95, 0.86, 0.73 and 1.20%, respectively. The highest phytase activity was found in the germinated faba bean for 144 hrs with partial purification by acetone 80%. Soaking process of legumes with ordinary water without addition of phytase extract led to minimal reduction of phytate content in all tested legumes. The reduction rate of phytate was 6 and 12% of its initial content in raw seeds after 8 and 12 hours, respectively. The hydrolysis of phytate was enhanced with increasing ratio of added phytase extract to water (45 : 55) during soaking for 12 hrs. A significant reduction in phytate content during the germination process as a result of the phytase extract addition was found. The loss rates of phytate were 47.9, 59.2, 70.4, 75.8 and 90.3% of its content in raw seeds after 24, 48, 72, 96 and 120 hrs respectively. The high loss of phytate content during soaking and germination was due to the addition of high activity enzyme extract as well as the endogenous enzyme effects. As a result of phytate hydrolysis during germination, the inorganic phosphorus(Pi) in all germinated legumes was librated in a large amounts with addition exogenous phytase compared to the phosphorus released by the native phytase.