Abstract:Heat treatment in electric cookers can give rice pleasant characteristic flavors, but there are still some limitations in improving the odor quality of aged Japonica rice. The characteristic compounds causing the off-flavor of aged Japonica rice were determined by gas chromatography-olfactometry-mass spectrometry and odor activity value. Gas chromatography-mass spectrometry was used to analyze the odor characteristics of aged Japonica rice with different soaking treatments. The effect of vacuum-assisted soaking on lipid oxidation degree of aged Japonica rice was investigated by analyzing the changes of lipase activity, composition of free fatty acid, peroxide value, and malondialdehyde content. The results showed that vacuum-assisted soaking at 50℃ for 10 min could regulate the process of lipid oxidation by inhibiting the catalytic activity of lipase in rice grains, and reduce the accumulated content of key aged flavor compounds such as hexanal, (E)-2-heptenal, nonanal and (E, E)-2, 4-decadienal by 12.4%, 4.2%, 100% and 53.8%, respectively, significantly improving the odor quality of aged Japonica rice cooked with an electric rice cooker.
