Differential analysis and bioactivity identification of Neurospora crassa metabolites based on okara by widely-targeted metabolomics

UHPLC-QqQ-MS widely-targeted metabolomics was used to analyze comparatively the okara-based metabolites of Neurospora crassa (the strain NC-a and NC-b) at fermented for 24 and 40 h. NC-b could produce cellulase and protease with higher activity than NC-a, especially in the later stage of fermenting okara, and their metabolic profiles between 24 and 40 h had significant difference. A total of 783 metabolites were identified, including 77 key bioactive pharmaceutical ingredients against six major diseases, among which flavonoids were the most abundant and diverse. It could be inferred that the okara fermented by NC-b exhibited higher health-promoting value than that by NC-a possibly due to more abundant flavonoids, and excessive fermentation could reduce flavonoids. The work demonstrated systematically the chemical basis of NC fermented okara as functional food ingredients, and thereby lay the groundwork for it as high value-added low-cost materials of food and medicine.