Preparation of decaffeinated and high caffeine powders from green tea

The aims of this study were to develop optimal conditions for decaffeination and spray drying procedures to produce decaffeinated and high caffeine powders from green tea (Camellia sinensis). Blanching the tea leaves with water at 100 °C for 4 min at a water-to-tea ratio of 20:1 mL/g removed 83% of the caffeine while retaining 94% of the catechins. The optimal spray drying conditions, which gave the highest yield of green tea powder and the highest concentrations of the naturally occurring epistructured catechins were found to be 180 °C for the inlet temperature and 115 °C for the outlet temperature. Using these optimal conditions, a decaffeinated green tea powder (7 mg/g caffeine) and a high caffeine powder (95 mg/g) were produced. These two green tea powders had excellent physical properties and could be used as instant teas by consumers or utilized in the food, cosmetic and nutraceutical industries.