不同粒径抹茶粉体物化特性研究

Study on Physicochemical Characteristics of Matcha Powder with Different Particle Sizes

以物化特性为指标,利用生产型球磨机将碾茶进行超微粉碎,得到中值粒径为117.094、60.176、40.041、30.646、25.282、21.090、19.199、14.209μm的抹茶,探究不同粒径下抹茶的物化特性。结果表明,随着粉碎时间的延长,粉体粒径逐渐减小,细胞破碎程度显著增加,但茶粉主要成分的官能团结构并未见改变;当粒度细化到一定程度后,比表面积和表面能增大,颗粒处于能量不稳定状态,易发生粘附及团聚现象;粉体的容重减小,这与粉体的孔隙率增大有关;由于茶样比表面积增大,粉体内部物质暴露,使得水分有所减少,总含水量降低;茶粉亮度逐渐升高,绿度增加;随着粉碎时间的延长,样品的茶多酚、游离氨基酸等物质含量呈现先增加后降低的趋势,抗坏血酸和EGCG等物质含量呈现减少的趋势。以上结果表明,超微粉碎过程对抹茶的物化特性总体影响显著。

Taking the physicochemical characteristics as indicators,the tea was superfine grinding by a production type ball mill to obtain Matcha with medium particle size of 117.094,60.176,40.041,30.646,25.282,21.090,19.199 and 14.209μm,and to explore the physicochemical characteristics of Matcha at different particle sizes.The results show that with the pulverization time prolonged,the particle size of the powder gradually decreased and the degree of cell breakage increased remarkably.However,the functional group structure of the main component of the tea powder did not change.When the particle size was refined to a certain extent,the specific surface area and surface energy increased,the particles were in an unstable energy state,and prone to adhesion and agglomeration.The bulk density of the powder reduced,which was related to the increase of the porosity of the powder.Due to the increased specific surface area of the tea sample,the internal substances of the powder exposed,so that the water content and total water content reduced.The brightness of tea powder gradually increased,and the greenness increased.With the pulverization time prolonged,the content of tea polyphenols,free amino acids and other substances incr eased first and then decreased,while the contents of ascorbic acid and EGCG tended to reduce.The above results show that the superfine grinding process had a significant impact on the physicochemical characteristics of Matcha.