Development of New Crushing Mill for Manufacturing Powdered Green Tea from Dried Tea Leaves

Abstract

A new batch-type crushing mill has been developed that enables efficient and stable processing of dried tea leaves to a powdered green tea representing high-quality powdered foodstuffs. The powdered green tea processed by the new mill has a quality equivalent to the powdered green tea processed by using a traditional stone mill. Its features are high uniformity of the grain size of the crushed powder, ease of grain size control, and deterioration-free colour, flavour and taste of the product due to the suppression of the increase in temperature throughout the operation. One new mill is equal to about twenty stone mills in a capacity. The effect of sterilization has been observed on the processed powder and the product meets the requirement of the Food Sanitation Law. The basis of the new crushing mill is a ball mill, and the added functions that enable excellent performance of the new mill are installation of equipment that allows both the revolution and rotation of the chamber and the addition of a horizontal centre shaft equipped with agitation pins inside the chamber. The new crushing mill has the possibility of application to various types of powdered foodstuffs and also the possibility of further development to a continuous-type crushing mill.