Exploring the influence of fruit ripeness on the microbiome, bioactive components, and flavor profiles of naturally fermented noni (Morinda citrifolia L.) juice.

Abstract

Raw fruit ripeness is an important factor affecting fermented noni fruit juice (FNJ). This study investigated the physicochemical properties, active and volatile components, microbiota, and functional characteristics of FNJ prepared from noni fruits at varying ripening stages. The results showed that deacetylasperulosidic acid (203.54-805.89 mg/L) and asperulosidic acid (102.78-393.41 mg/L) were detected across in all FNJs during fermentation. As noni fruit ripens, the levels of octanoic acid and hexanoic acid in FNJs gradually decreased, while the content of esters significantly increased, particularly during the final stage of ripeness. Metagenomic analysis revealed that Acetobacter sp. and Gluconobacter sp. were core microbes responsible for FNJs, primarily contributing to fatty acid metabolism. Correlation analysis further indicated that the fruit's ripeness significantly influenced its functional properties and volatile components of FNJs. This study offered new insights into selecting the optimal ripeness of noni fruits for the preparation of FNJ and its potential industrial applications.