Effect of thermal treatment on aroma compounds formation and microbial succession during greengage spontaneous fermentation

• Thermal treatment increased the acidity of greengage wine. • Thermal treatment enhanced the synthesis of acetate esters and fatty acids. • Thermal treatment accelerated volatile decomposition in the end of fermentation. • PLS was used to reveal the key microbes corresponding to the greengage wine aroma. Thermal treatment is a primary postharvest technology for greengage. This study aimed to investigate the effects of thermal treatment on aroma development and microbial succession during greengage spontaneous fermentation. Results indicated that thermal treatment enhanced citric acid and acetic acid levels. In the early fermentation stage, it promoted the release of volatile compounds in greengage wine, especially acetate esters and fatty acids. However, by the end of fermentation, volatile content dropped significantly compared to the control group. Heating also led to lower fungal and bacterial diversity in the early fermentation stage. Throughout fermentation process, non- Saccharomyces cerevisiae like Pichia, Candida , and Starmerella were dominant. VPA and Mantel analysis revealed that organic acids most significantly impact microbial metabolism, while heating weakens this effect. PLS analysis showed that Candida, Pichia , and Starmerella were major aroma contributors, and heating increased Lactobacillus and Acetobacter 's aroma contributions. To sum up, thermal treatment has the ability to rapidly initiate the fermentation of greengage wine, releasing more volatile compounds early on, but causing a significant drop in volatile content later. This study provided a theoretical basis for understanding the impact of thermal treatment on quality of processed fruit products.