Effect of temperature regulation on microbial community, volatile flavours, amino acid profiles, and iridoid glycosides during noni (Morinda citrifolia L.) fruit fermentation.

Noni fruit has an unpleasant flavour but is highly bioactive. Therefore, it is necessary to clarify the effect of temperature regulation on quality of fermented noni fruit. In the present study, the formation of flavours, amino acid profiles, and iridoid glycosides during noni fruit fermentation at different temperatures were investigated. We initially found that different temperatures affected core microbial communities. The general evolutionary trends of Acetobacter and Gluconobacter were influenced by different temperatures. Furthermore, high temperature helped maintain low octanoic and hexanoic acids. Subsequently, we found that high temperature improved total amino acids and iridoid glycosides. The correlation network analysis revealed that bacterial communities impacted the quality (volatile flavours, amino acid profiles, and iridoid glycosides) of fermented noni fruit. Overall, altering the temperature induced variations in microbial communities and quality during the noni fruit fermentation process. These results are instrumental in the pursuit of quality control in natural fermentation processes.