低频静磁场对发芽玉米酚类物质富集及降糖活性的影响

本实验以玉米（‘吉单66’）为研究对象，采用磁场强度为2.5、3.5、4.5 mT的低频静磁场分别对玉米进行12、24、36、48、60、72 h的处理，随后在25 ℃下发芽96 h（以未经磁场处理发芽至96 h的玉米作为对照），分析发芽玉米主要生理指标、酚类物质含量、多酚代谢关键酶活力以及酚类物质降糖活性的变化情况。结果表明：在磁场强度为3.5 mT条件下处理60 h后，与对照组相比，玉米籽粒的芽长、发芽率明显提高，结合酚、游离酚含量分别提高72.72%、47.16%，丁香酸和对香豆酸在游离酚中含量提高显著（P＜0.05）；此外，经适度磁场处理后，苯丙氨酸解氨酶、4-香豆酸-CoA连接酶、肉桂酸-4-羟化酶活性得到提高；体外降糖实验结果表明，游离酚和结合酚对α-葡萄糖苷酶、α-淀粉酶活性的抑制作用普遍增强。结论：静磁场处理能够促进玉米发芽、诱导酚类物质的积累，同时还能够提高发芽玉米酚类物质的降糖效果。

Effect of Low-Frequency Static Magnetic Field on Enrichment of Phenolics and Hypoglycemic Activity of Germinated Maize (Zea mays L.)

Maize kernels (cv. ‘Jidan 66’) were exposed to different intensities (2.5, 3.5 and 4.5 mT) of low-frequency static magnetic fields for different time periods (12, 24, 36, 48, 60 and 72 h) and germinated at 25 ℃ for 96 h. The changes in the growth indices, the phenolic contents, the hypoglycemic activity of phenolic compounds and the key enzyme activities related to polyphenol metabolism in germinated maize kernels were investigated. The results showed that the sprout length and germination rate of maize seeds treated at magnetic field intensity of 3.5 mT for 60 h were significantly increased, and the contents of bound and free phenols were increased by 72.72% and 47.16%, and the contents of syringic acid and p-coumaric acid were also significantly increased compared to the untreated control (P < 0.05). In addition, the activity of phenylalanine ammonia lyase (PAL), 4-coumaric acid-CoA ligase (4CL), and cinnamate 4-hydroxylase (C4H) were improved under low frequency static magnetic field, and the α-glucosidase and α-amylase inhibitory activity of bound and free phenolics were enhanced. These pieces of evidence indicated that low frequency static magnetic field can promote the growth of maize seeds and the accumulation of phenolic compounds, and improve the hypoglycemic activity of phenolic compounds in germinated maize seeds .