Improving functionality and metabolite profiles of black sapote juice through lactic acid bacteria fermentation

Black sapote, a tropical fruit rich in vitamins and bioactive compounds, is known for its high antioxidant activity. However, its rapid deterioration during postripening poses challenges for transportation and commercialization. Although lactic acid bacterial (LAB) fermentation is widely used to increase the nutritional content and shelf-life of various foods, its application to black sapote juice (BSJ) has not been explored until now. This study investigated the impact of LAB strains (Lactococcus cremoris, Lacticaseibacillus rhamnosus, and Limosilactobacillus reuteri) on the quality of BSJ. These results demonstrate that BSJ is an excellent substrate for LAB proliferation. Fermentation significantly altered the sugar and acid contents and notably increased the concentrations of phytochemicals and antioxidant activity. The ABTS radical scavenging activity of L. rhamnosus increased by 76%, and its total phenolic content improved by 35%. Furthermore, volatile compound and metabolomic profiling analyses indicated that fermentation significantly increased the relative abundances of benzaldehyde, linalool, ascorbic acid, and caffeic acid and generated novel compounds such as acetoin. Therefore, LAB fermentation markedly altered both the flavor profile and metabolic characteristics of BSJ, influencing multiple metabolic pathways. These findings open new avenues for BSJ processing, positioning it as a promising candidate for the development of innovative functional foods.