UV-B辐射对紫花苜蓿幼苗品质和抗氧化性的影响

Effects of UV-B radiation on quality and antioxidant properties of alfalfa(Medicago sativa L.) sprouts

以紫花苜蓿幼苗（Medicago sativa L.）为材料,对紫花苜蓿幼苗分别进行了2、4、6、8、10、12 h UV-B辐射处理,以白光（W）为对照,研究UV-B对其营养品质、药用价值及抗氧化性的影响。结果表明：与对照组相比,UV-B照射4、6、8、10 h的可溶性糖含量分别增加了68.4%、57.3%、71.1%、43.9%,差异均达到极显著水平（P〈0.01）;照射4 h后可溶性蛋白含量增加了22.4%,差异达到极显著水平（P〈0.01）;UV-B照射后,苯丙氨酸解氨酶（PAL）的活性于（4-10）h之间分别增加了49.2%、49.4%、66.7%、69.5%,差异均达到极显著水平（P〈0.01）;总酚、类黄酮、花青素等紫外吸收物质的含量显著提高：照射4 h时,总酚含量增加了5.3%,差异达到极显著水平（P〈0.01）;照射10 h时,类黄酮含量增加了4.6%,差异达到极显著水平（P〈0.01）;花青素含量于照射8、10、12 h时分别增加了44.4%、81.8%、63.7%,差异均达到极显著水平（P〈0.01）;此外,UV-B辐射后的紫花苜蓿幼苗抗氧化能力明显提高,照射12 h时增加了7.8%,差异达到极显著水平（P〈0.01）。由此可见,UV-B辐射可以显著提高紫花苜蓿幼苗的品质及抗氧化能力。

The effects of UV-B radiation on nutritional quality, medicinal value and antioxidant properties of alfalfa（Medicago sativa L.） sprouts were investigated with treatments of 2 h, 4 h, 6 h, 8 h, 10 h, 12 h respectively in comparison with those of white. The results showed that the soluble sugar contents of UV-B increased extremely significantly by 68.4%, 57.3%, 71.1%, 43.9% after 4 h, 6 h, 8 h, 10 h respectively（p〈0.01）. The soluble protein contents of UV-B increased extremely significantlyby 22.4% after 4 h（p〈0.01）. The phenylalanine ammonia-lyase（PAL） activity of UV-B increased extremely significantly by 49.2%, 49.4%, 66.7%, 69.5% after 4 h, 6 h, 8 h, 10 h respectively（p〈0.01）. Total phenolics, flavonoids and total anthocyanin contentsof UV-B were extremely significantly improved： total phenolic contentsincreased by 5.3% after 4 h（p〈0.01）. Flavonoids contents increased by 4.6% after 10 h（p〈0.01）.Total anthocyanin contentsincreased by 44.4%, 81.8%, 63.7% after 8 h, 10 h, 12 h respectively（p〈0.01）. Moreover, the 1,1-diphenyl-2-picrylhydrazyl（DPPH） radical scavenging activity increased extremely significantly by 7.8% after 12 h（p〈0.01）. These results revealed that UV-B radiation were effective in promoting quality and antioxidant properties of alfalfa.