Lactic acid fermentation of a novel Sea buckthorn-monk fruit beverage: Phenolic profile, volatile compounds, and antidiabetic and antihypertensive potential

Functional foods offer health benefits that extend beyond basic nutrition, addressing critical public health challenges such as diabetes and hypertension. This study developed a novel lactic acid bacteria (LAB)-fermented beverage integrating sea buckthorn and monk fruit, two bioactive-rich ingredients with complementary properties. Sea buckthorn provides a robust profile of antioxidants, while monk fruit's natural sweetness and low glycemic index make it an ideal ingredient for health-conscious consumers. Three LAB strains (Lactiplantibacillus plantarum (LP), Lacticaseibacillus paracasei (LPC), and Lactobacillus acidophilus (LA) were utilized individually and in combination to evaluate their impact on the beverage's bioactive and functional properties. Phenolic profiling (HPLC) revealed 13 phenolic compounds, with LPC fermentation achieving the highest total polyphenol content (232.50 ± 2.37^a). Quinic acid and neochlorogenic acids were most abundant in all samples, with significantly elevated concentrations observed in fermented samples. Remarkably, LAB fermentation induced the formation of kaempferol, a phenolic compound with well-documented therapeutic properties, which was absent in the control. Volatile compound analysis (HS-SPME-GC–MS) and aroma profiling (E-nose) demonstrated that LP and LPC + LA fermentations enhanced key volatile compounds and improved sensory complexity, as corroborated by aroma profiling. The functional properties of the beverage were assessed through α-amylase, α-glucosidase, and angiotensin-converting enzyme (ACE) inhibitory assays. LP and LP + LPC demonstrated superior antidiabetic and antihypertensive potential. A Mantel test confirmed strong correlations between phenolic profiles and bioactivities, substantiating the role of LAB fermentation in enhancing therapeutic potential.