微波处理对大米脂质和脂氧合酶的影响

Effect of microwave treatment on the lipids and lipoxygenase of rice

研究了微波处理对大米脂质和脂氧合酶活性的影响。结果表明,微波(700 W,100 s)处理后,糙米和精米的水分、总脂质含量及其游离态和结合态脂质的脂肪酸组成的变化不显著。微波处理的糙米的脂氧合酶活性[(1.26±0.12)ΔOD/min·g样品]明显低于对照糙米[(2.13±0.18)ΔOD/min·g样品];并且经过37℃储藏90 d后,微波处理的糙米的脂氧合酶活性[(1.12±0.17)ΔOD/min·g样品]同样显著低于对照糙米[(1.85±0.16)ΔOD/min·g样品]。微波处理糙米的游离脂肪酸值的增加不显著,与微波能够显著钝化稻米的脂肪氧化酶活性、延缓稻米脂肪的氧化有关。研究结果为进一步开发稻米微波保鲜技术提供了基础数据。

The effect of microwave treatment on the lipids and lipoxygenase of rice was investigated in the present research. The research results showed that the changes of moisture, lipid contents and fatty acid composition in the free and bound lipids of brown rice and milled rice were not significant after microwave treatment（700 W, 100 s）. The lipoxgenase activity of brown rice [（1.26±0.12）ΔOD/min·g sample] treated with microwave was significantly lower than that of control [（2.13±0.18）ΔOD/min·g sample]. The lipoxgenase activity of brown rice [（1.12±0.17）ΔOD/min·g sample] treated with microwave was also significantly lower than that of control [（1.85±0.16）ΔOD/min·g sample] following storage at 37 ℃ for 90 days. The increase of free fatty acid value of brown rice treated with microwave was not significant, which was related to the ability of microwave to passivate the lipid oxidase activity of rice and delay the oxidation of rice lipids. This present research provides basic date for the further development of rice microwave preservation technology.