Improving the Physicochemical Properties, Organic Acids, Amino Acids, Volatile Organic Compounds, and Metabolites of Laohan Melon Juice Through Fermentation With Different Lactic Acid Bacteria

Fermentation with various lactic acid bacteria (LAB) strains was evaluated for its impacts on the physicochemical properties, functional components, and volatile and nonvolatile metabolic features of Laohan melon juice (LMJ). The results revealed that lactic acid fermentation decreased sugar contents and pH values, while simultaneously modifying juice color parameters. Fourteen amino acids were detected, with higher levels of Leu, Ile, and Val after fermentation, contributing to the synthesis of floral and fruity compounds. In total, 66 volatile organic compounds (VOCs) were detected, and fermented LMJ exhibited greater diversity and higher abundance of VOCs than unfermented LMJ. The metabolic pathway of amino acids and the biosynthesis of flavonoids may be associated with these differences. These strain‐specific effects are critical for enhancing the flavor and functional attributes of fermented LMJ, and offer a theoretical basis for the development of high‐quality Laohan melon juice products.