Formation of dimethyl sulfide from the decomposition of S-methylmethionine in tea (Camellia sinensis) during manufacturing process and infusion brewing

Dimethyl sulfide (DMS) is a typical odorant contributing a cooked corn-like odor to tea (Camellia sinensis). In the study, noticeable increases of DMS (>350%) occurred in green, black, yellow, and white tea during brewing. Thermal model and quantitative analysis of S-methylmethionine (SMM) confirmed the thermal decomposition of SMM into DMS (44-80%) in tea infusion. The quantitative analysis on green and black tea manufacturing processes demonstrated thermal decomposition of SMM (12% and 9.0%, respectively) leads to DMS formation during the drying step. Besides, DMS was firstly suggested to be biosynthesed from yet unknown precursors due to high concentrations in fresh leaves (180 and 1700 mu g/kg) and increases during rolling (190 and 2800 mu g/kg) and fermentation (6400 mu g/kg in black tea). The findings provided new insight of DMS formation from the decomposition of SMM in tea during manufacturing process and infusion brewing, which also help exploring its biosynthetic pathway during tea production.

Automated summary

The study found that the formation of dimethyl sulfide (DMS) in tea during the manufacturing process and infusion brewing is due to the thermal decomposition of S-methylmethionine (SMM). It was also suggested that there may be other unknown precursors involved in the biosynthesis of DMS during tea production. These findings provide new insights into the formation of DMS in tea and its biosynthetic pathway.