Chen Yulian, Wang Yuanliang, Chen Jiaxu, Tang Hao, Wang Chuanhua, Li Zongjun, Xiao Yu
Hunan Yancun Ecological Farming Technology Co., Ltd. Changsha 410129 China.
College of Food Science and Technology, Hunan Agricultural University Changsha 410128 China
RSC Adv. 2020 Apr 30;10(29):16928-16941. doi: 10.1039/c9ra10344a. eCollection 2020 Apr 29.
In this study, soybean ( L.) was bioprocessed with fungal strain YL-1 by using the solid-state fermentation (SSF) technique. The effect of SSF on total phenolic content (TPC), isoflavone compositions, and antioxidant activity of soybean during different fermentation periods was evaluated. Results showed that TPC and isoflavone aglycones were significantly increased, whereas glucoside isoflavones were remarkably reduced during SSF. After 15 days of SSF, the TPC, daidzein, genistein, and total aglycones of soybeans were approximately 1.9-, 10.4-, 8.4-, and 9.4-fold higher, respectively, than those of non-fermented soybeans. During SSF, β-glucosidase activity was very high, whereas α-amylase and protease activities were at moderate levels, and cellulase activity was relatively low. A highly positive correlation was found between TPC and the activities of α-amylase (correlation coefficient = 0.9452), β-glucosidase ( = 0.9559), cellulase ( = 0.9783), and protease ( = 0.6785). Linear analysis validated that the β-glucosidase produced by contributed to the bioconversion of soybean isoflavone glucosides into their aglycone forms. The DPPH radical and ABTS˙ scavenging activity, reducing power, and ferric reducing antioxidant power of soybeans were considerably enhanced during SSF. Principal component analysis and Pearson's correlation analysis verified that the improvement in TPC and isoflavone aglycone content during SSF was mainly responsible for the improved antioxidant capacity of soybeans. Thus, our results demonstrated that solid-state bioprocessing with is an effective approach for the enhancement of the TPC, isoflavone aglycones, and antioxidant capacity of soybeans. Bioprocessed soybean products might be a healthy food supplement rich in antioxidants compared with non-fermented soybean and thus could be a source of natural antioxidants.
在本研究中，采用固态发酵（SSF）技术，利用真菌菌株YL-1对大豆（L.）进行生物加工。评估了固态发酵对大豆在不同发酵时期总酚含量（TPC）、异黄酮组成和抗氧化活性的影响。结果表明，在固态发酵过程中，总酚含量和异黄酮苷元显著增加，而葡萄糖苷异黄酮显著减少。固态发酵15天后，大豆的总酚含量、大豆苷元、染料木黄酮和总苷元分别比未发酵大豆高出约1.9倍、10.4倍、8.4倍和9.4倍。在固态发酵过程中，β-葡萄糖苷酶活性非常高，而α-淀粉酶和蛋白酶活性处于中等水平，纤维素酶活性相对较低。发现总酚含量与α-淀粉酶活性（相关系数 = 0.9452）、β-葡萄糖苷酶活性（ = 0.9559）、纤维素酶活性（ = 0.9783）和蛋白酶活性（ = 0.6785）之间存在高度正相关。线性分析证实，由 产生的β-葡萄糖苷酶有助于大豆异黄酮葡萄糖苷向其苷元形式的生物转化。在固态发酵过程中，大豆的DPPH自由基和ABTS˙清除活性、还原能力和铁还原抗氧化能力显著增强。主成分分析和Pearson相关分析证实，固态发酵过程中总酚含量和异黄酮苷元含量的提高是大豆抗氧化能力提高的主要原因。因此，我们的结果表明，用 进行固态生物加工是提高大豆总酚含量、异黄酮苷元和抗氧化能力的有效方法。与未发酵大豆相比，生物加工的大豆产品可能是一种富含抗氧化剂的健康食品补充剂，因此可能是天然抗氧化剂的来源。
