固态发酵诱导大豆Glyceollins的积累及抗氧化评价

Accumulation of Soybean Glyceollins Induced by Solid-state Fermentation and Antioxidant Activity Evaluation

大豆异戊烯基异黄酮(Glyceollins)作为植物抗毒素家族的一员,具有雌激素受体调节剂活性及防治绝经后骨质疏松症等功效。本文以南农99-6大豆为原料,通过筛选食品级霉菌菌株,优化固态发酵条件,实现糖苷型异黄酮向苷元及Glyceollins的转化和积累,并对发酵大豆进行体外抗氧化活性评价。结果表明,大豆经过微生物诱导子刺激能实现异黄酮向苷元及Glyceollins的转化及积累,且转化效率受霉菌种类、接种量、发酵时间、损伤及发芽前处理影响。最优条件为,选用孢子浓度为107个/g大豆的米曲霉(Aspergillus oryzae)CICC2436对大豆进行固态发酵3 d后可获得富含苷元和Glyceollins的发酵大豆;同时,损伤及发芽前处理均能促进糖苷向苷元的转化,但Glyceollins积累主要受损伤这一诱导子的影响。DPPH自由基清除率及铁还原力证实,发酵大豆具有较高的体外抗氧化活性。

Soybean glyceollin is a member of the phytoalexin family, and shows estrogen receptor modulator activity. Therefore, it has been used to control and prevent postmenopausal osteoporosis. In this study, using Nannong 99-6 soybean as the raw material, the conversion of soybean glucosidic isoflavones into aglycone and glyceollins, and the accumulation of aglycone and glyceollins were achieved by screening food-grade fungal strains and optimizing the solid-state fermentation process. Furthermore, the in vivo antioxidant activity of fermented soybean was evaluated. The results indicated that stimulation by microbial elicitors could result in the successful conversion of isoflavone to aglycone and glyceollins, and in the consequent accumulation of aglycone and glyceollins in soybeans. Moreover, the conversion efficiency was influenced by inoculation conditions（microorganism species, inoculation concentration, fermentation time, injury treatment, and germination pretreatment）. The optimal solid-state fermentation process to obtain aglycone- and glyceollins-rich soybean-fermented products was to carry out the solid-state fermentation of soybeans with Aspergillus oryzae CICC2436 at a spore concentration of 107/g soybeans for three days. Moreover, the injury and germination pretreatments were also conducive to the conversion of soybean isoflavone, but the accumulation of glyceollins was mainly affected by the elicitor–injury treatment. The 2, 2-diphenyl-1-picrylhydrazyl（DPPH） radical scavenging rate and ferric-reducing power value confirmed the high in vitro antioxidant activity of fermented soybean.