浏阳豆豉发酵过程中抗氧化成分及活性变化研究

通过测定大豆异黄酮、总黄酮、总多酚含量的变化,结合发酵过程中浏阳豆豉的抗氧化活性的变化,来探讨浏阳豆豉抗氧化活性变化的机理。结果表明:虽然总黄酮与总大豆异黄酮的含量逐步减少,但发酵初期原料中大豆异黄酮主要为糖苷型(占85.75%),而发酵末期则主要为更具活性的苷元型大豆异黄酮(占81.41%),且总多酚经发酵从2.78 mg/g提升至5.76 mg/g,发酵最后一天(L20)豆豉的总抗氧化能力、DPPH·、·OH、O₂^-·清除率分别增加至1088.91 U/g、93.67%、90.24%、88.38%,此外相关性结果表明苷元型大豆异黄酮要比总多酚对豆豉抗氧化活性的影响更大。实验证明发酵有助于大豆中总多酚的增加以及糖苷型大豆异黄酮向苷元型大豆异黄酮转换,这是提高豆豉抗氧化能力及功能性的关键因素之一。

Study on Antioxidant Components and Activity Changes of Liuyang Douchi during Fermentation

In order to investigate underling mechanism for the antioxidant activity of Liuyang Douchi,the contents of antioxidants(including polyphenols,flavonoids and soybean isoflavones)and the antioxidant activity of Liuyang Douchi during fermentation were measured. Results showed that although the content of total flavonoids of Douchi decreased gradually,the glycoside type soybean isoflavones accounted for 85.75% at the beginning of fermentation while aglyn-type soybean isoflavones accounted for 81.41% at the end of the fermentation. The total polyphenols increased from 2.78 mg/g to 5.76 mg/g by fermentation,and the total antioxidant capacity,DPPH·,hydroxide(·OH),superoxide anion(O₂-·)radical-scavenging rate of Douchi increased to 1088.91 U/g,93.67%,90.23%,88.38%,respectively.In addition,the results of correlation analysis showed that aglycogenic soybean had a greater effect on the antioxidant activity of Douchi than total polyphenols.It indicated that fermentation was helpful to the increase of total polyphenols in soybean and the conversion of glycosidic soybean isoflavones to aglycone isoflavones,which was one of the key factors to enhance the antioxidant capacity and improve the functionality of Liuyang Douchi.