Stirred media mill: A novel efficient technology for improving the physicochemical properties and aroma of matcha

Matcha is a finely ground powder made from green tea leaves called tencha. Stirred media mills have the potential to produce matcha efficiently, but there is limited research on their application for matcha grinding. Our investigation focused on analyzing the changes in particle characteristics, nutrient composition, and volatile components during the grinding process at various time intervals (20–140 min). We observed that as the grinding time increased from 20 to 140 min, the median particle size of MP decreased from 330.3 to 17.1 μm, the specific surface area increased. The color of the matcha powder became brighter and greener, and the active polyphenols and amino acids were successfully preserved. Moreover, the grinding process facilitated the formation of benzaldehyde and α-ionone, which are characteristic flavor substances of matcha. These results indicate that the utilization of SMM shows promise as a technology for preparing matcha with desirable appearance, nutritional composition, and aroma.