Isoflavone Content and Profile Comparisons of Cooked Soybean-Rice Mixtures: Electric Rice Cooker versus Electric Pressure Rice Cooker

摘要

This study examined the effects of heat and pressure on the isoflavone content and profiles of soybeans and rice cooked together using an electric rice cooker (ERC) and an electric pressure rice cooker (EPRC). The total isoflavone content of the soybean-rice mixture after ERC and EPRC cooking relative to that before cooking was similar to 90% in soybeans and 14-15% in rice. Malonylglucosides decreased by an additional similar to 20% in EPRC-cooked soybeans compared to those cooked using the ERC, whereas glucosides increased by an additional similar to 15% in EPRC-cooked soybeans compared to those in ERC-cooked soybeans. In particular, malonylgenistin was highly susceptible to isoflavone conversion during soybean-rice cooking. Total genistein and total glycitein contents decreased in soybeans after ERC and EPRC cooking, whereas total daidzein content increased in EPRC-cooked soybeans (p < 0.05). These results may be useful for improving the content of nutraceuticals, such as isoflavones, in soybeans.