Processing of green tea pastes by micro wet milling system: Influences on physicochemical and functional properties

摘要

This study aimed to develop green tea paste using a new micro wet milling (MWM) system. The influence of milling conditions on the particle size, morphology, solubility, and antioxidant properties of Matcha, shaded Yabukita, unshaded Yabukita, and Hojicha pastes were studied. MWM green tea paste retained smaller particles, better color, higher solubility, and antioxidant properties than the dry milled Matcha paste. Storage temperature and time affected the stability of ascorbic acid and visual green color at 20, 4, -18, and -60 degrees C for four weeks. Kinetic analysis demonstrated that first-order kinetic models could predict the degradation of ascorbic acid and the reduction in visual green color of green tea pastes during storage. Temperature-dependent rate constants of ascorbic acid and color of green tea pastes obeyed the Arrhenius relationship. The total viable count revealed that green tea paste could be stored for 7 days at 20 degrees C and 21 days at 4 degrees C within the permissible limit.