豆渣固态发酵过程中主要营养成分及抗氧化特性变化

Changes in Major Nutritional Components and Antioxidant Activity of Fermented Okara

目的:研究豆渣固态发酵过程中主要营养成分及抗氧化特性的动态变化,为利用豆渣开发功能性食品或配料提供理论参考。方法:分别以米根霉、少孢根霉为发酵菌种对豆渣进行固态发酵,测定发酵过程中还原糖含量、可溶性蛋白含量、纤维素酶活力、糖化酶活力、蛋白酶活力及还原力、2,2’-联氮-二3-乙基-苯并噻唑-6-磺酸二铵盐(2,2’-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid),ABTS)自由基清除能力、Fe^(2+)螯合能力为评价指标的抗氧化活性的变化。结果:与未发酵豆渣相比,还原糖含量、可溶性蛋白含量、纤维素酶活力、糖化酶活力、蛋白酶活力均随着发酵时间的延长而增加。豆渣经米根霉发酵24 h,其还原力、ABTS^+·清除活性、Fe^(2+)螯合能力分别提高了1.63、1.48、2.82倍;经少孢根霉发酵24 h,分别提高了1.88、1.63、3.18倍。结论:用米根霉和少孢根霉发酵豆渣可以提高豆渣的营养成分及抗氧化活性。

The objective of this work was to assay the effect of solid-state fermentation（SSF） on the major nutritional components and antioxidant activity of okara with the aim to obtain value-added fermented okara and to develop it into functional foods. Individual cultures of Rhizopus oryzae or Rhizopus oligosporus were used to ferment okara in solid-state cultivation and changes in reducing sugar, soluble protein, cellulase activity, glycoamylase activity, and protease activity were expored during the fermentation. In addition, reducing power, 2,2-azinobis（3-ethylbenzothiazoline-6-sulfonic acid） diammonium salt（ABTS） scavenging capacity and ferrous ion chelating activity assays were carried out to investigate the antioxidant activities of fermented okara. Results showed that reducing sugar, soluble protein, cellulase activity, glycoamylase activity and protease activity increased significantly as fermentation progressed. Fermented okara showed high antioxidant activities in terms of reducing power, ABTS^＋· scavenging capacity and ferrous ion-chelating activity. Compared with the unfermented control, these antioxidant activities increased by 1.63, 1.48 and 2.82 folds for okara fermented by Rhizopus oryzae for 24 h, and by 1.88, 1.63 and 3.18 folds for okara fermented by Rhizopus oligosporus for 24 h, respectively. Thus, the present study showed that fermented okara with enhanced nutritional properties and antioxidant capacity can be served as nutraceuticals and functional foods for health promotion.