Analysis of Metabolic Differences and Core Regulatory Pathways in Lactic Acid Bacteria-Fermented Broths of Different Ziziphus jujuba Mill. Varieties Based on LC-MS Untargeted Metabolomics.

Ziziphus jujuba Mill. is a characteristic resource with both medicinal and edible values. At present, its lactic acid bacteria-fermented products are plagued by ambiguous variety selection and low added value. To clarify the variety-specific regulatory effects of Z. jujuba cultivars on metabolic profiles during lactic acid bacteria fermentation, this study analyzed the metabolic characteristics of fermented broths of Tan jujube, Jun jujube, and Ban jujube under a unified fermentation system using LC-MS untargeted metabolomics technology. Significantly differential metabolites were screened with the criteria of p < 0.05 and VIP > 1, and the metabolic regulatory mechanisms were further elucidated, combined with KEGG pathway enrichment analysis. The results showed that a total of 570 metabolites were identified in the three fermented broths. Tan jujube was enriched in linolenic acid, Ban jujube was rich in D-xylitol and dethiobiotin, and Jun jujube had prominent contents of S-adenosylmethionine and pyridoxine. All the aforementioned metabolites are involved in important physiological processes such as anti-inflammation and intestinal homeostasis maintenance. The differential metabolites were mainly enriched in 6 key pathways, including central carbon metabolism, ABC transporters, and phenylpropanoid biosynthesis, among which central carbon metabolism and ABC transporters were the core regulatory pathways. This study constructed an association network of Z. jujuba variety-differential metabolite-key pathway, systematically elucidated the metabolic differentiation mechanisms of fermented broths from different Z. jujuba cultivars, and provided a scientific basis for the precise selection of Z. jujuba varieties dedicated to fermentation and the targeted development of high-value-added functional fermented foods.