Gao Ya Xin, Xu Bin, Fan Hai Ru, Zhang Meng Ran, Zhang Li Jing, Lu Cong, Zhang Na Na, Fan Bei, Wang Feng Zhong, Li Shuying
Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, No. 2 Yuan Ming Yuan West Road, Beijing 100193, China.
Food Res Int. 2020 Dec;138(Pt A):109686. doi: 10.1016/j.foodres.2020.109686. Epub 2020 Oct 11.
Microbial fermentation can endow food with unique flavors, increase its nutritional value and enhance functional characteristics. Our previous research has shown that liquid fermentation of soymilk by Bacillus subtilis BSNK-5 imparted new functional properties of to the fermented product via production of nattokinase. In this study, in order to further investigate the changes in the flavor, nutritional quality and functional characteristics of soymilk during fermentation using proton nuclear magnetic resonance (H NMR) metabolomics to monitor the metabolite profile of BSNK-5-fermented soymilk. A total of 44 differential metabolites were identified between BSNK-5-fermented soymilk and uninoculated/unfermented soymilk, among which the levels of flavor-related substances (acetate, isovalerate and 2-methylbutyrate), nutrient-related substances (12 free amino acids), and functional substances (taurine, GABA and genistein) significantly increased after fermentation. These metabolites were closely associated with eight potential metabolic pathways. This work highlighted the significance of BSNK-5 strain in improving the nutritional quality and functional characteristics of fermented soymilk; however, the use of the strain also caused flavor deterioration. This study lays a theoretical foundation for the improvement and development of fermented soy products via liquid fermentation with B. subtilis.
微生物发酵可以赋予食品独特的风味，增加其营养价值并增强功能特性。我们之前的研究表明，枯草芽孢杆菌BSNK-5对豆浆进行液体发酵，通过产生纳豆激酶赋予了发酵产品新的功能特性。在本研究中，为了进一步研究豆浆发酵过程中风味、营养品质和功能特性的变化，采用质子核磁共振（H NMR）代谢组学技术监测BSNK-5发酵豆浆的代谢产物谱。共鉴定出44种BSNK-5发酵豆浆与未接种/未发酵豆浆之间的差异代谢物，其中发酵后风味相关物质（乙酸、异戊酸和2-甲基丁酸）、营养相关物质（12种游离氨基酸）和功能物质（牛磺酸、γ-氨基丁酸和染料木黄酮）的含量显著增加。这些代谢物与8条潜在代谢途径密切相关。这项工作突出了BSNK-5菌株在改善发酵豆浆营养品质和功能特性方面的重要性；然而，该菌株的使用也导致了风味劣化。本研究为利用枯草芽孢杆菌进行液体发酵改善和开发发酵豆制品奠定了理论基础。
