真空辅助浸泡对陈粳米饭风味的影响

Effect of Vacuum-Assisted Soaking on Flavor of Aged Japonica Rice

摘要:

电饭煲热处理可赋予米饭怡人的特征风味，但其在改善陈粳米饭的气味品质方面仍存在一定的局限。本研究借助气相色谱-嗅闻-质谱和气味活性值确定了造成陈粳米饭不良气味的特征化合物。采用气-质联用对不同条件浸泡处理的陈粳米饭气味特性进行分析，并结合脂肪酶活力、游离脂肪酸组成、过氧化值和丙二醛含量的变化剖析真空辅助浸泡对陈粳米脂质氧化程度的影响。结果表明，采用50 ℃真空辅助浸泡处理10 min可以通过抑制米粒中脂肪酶的催化活性，调控脂质氧化的进程，使己醛、(E)-2-庚烯醛、壬烯醛、(E, E)-2, 4-癸二烯醛等关键陈味物质的含量分别下降了12.4%、4.2%、100%、53.9%，显著改善了电饭煲蒸煮陈粳米饭的气味品质。

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.