Metabolomics analysis functional metabolites shaped by Ganoderma lucidum fermentation of daylily.

Edible fungi fermentation is an effective strategy for enhancing the functional value of traditional foods, while postbiotics offer multiple health benefits, primarily produced through heating. This study aimed to uncover the key components and metabolic mechanisms in Ganoderma lucidum BZ5-fermented daylilies in heat processing, providing a scientific basis for developing novel functional foods. The fermentation parameters (including daylily concentration, glucose amount, inoculum size, and fermentation period) were optimized using a single-factor and response surface methodology. Under the optimized conditions (0.5% (w/v) daylily, 1% (w/v) glucose, 10% (v/v) inoculum, 5 days), the metabolite profiles of fermented and control samples were comprehensively analyzed by UPLC-MS/MS-based metabolomics. A total of 1,433 metabolites were identified. The addition of daylily, glucose, and trace elements significantly altered the metabolic profile, particularly facilitating the diverse production of organic acids while maintaining a stable total acid content. Among the significantly altered metabolites (including amino acids, ketones, vitamins, alkaloids, and carbohydrates), sinapinic acid exhibited the most dramatic increase and a strong correlation with fermentation, suggesting its potential as a characteristic marker of the heating process in this system. Notably, the level of the potent antioxidant L-ergothioneine increased significantly upon the addition of daylilies. This study delineates the specific metabolic reprogramming induced by G. lucidum BZ5 fermentation in daylilies, highlighting sinapinic acid and L-ergothioneine as key bioactive constituents. These findings give key insights into the composition and formation of functional ingredients in the fungal-fermented plant system. They also laid a strong foundation for developing G. lucidum functional foods with enhanced health-promoting effects.