冷冻干燥技术加工高绿度抹茶的研究

Study on the Processing of High Green Matcha by Freeze-drying Technology

色泽是衡量抹茶品质的重要因素之一,如今抹茶初制加工中的蒸汽、热风等杀青技术能最大程度地保持茶叶原有的绿色,而干燥过程中的高温会导致色素氧化和叶绿素脱镁,从而使抹茶绿度损失,所以干燥方式的创新是提升抹茶绿度的关键。本试验选取3种茶树鲜叶,经蒸汽、热风杀青后随机取样作为冻干原料,取同品种用传统干燥方式加工的碾茶混样作为试验对照,采用冷冻干燥技术所得的冻干抹茶,较传统烘干加热干燥的抹茶叶绿素含量明显提高,绿度值提升了13%~25%,且氨基酸和茶多酚等内含物含量变化不明显。通过审评发现冻干抹茶略带青味,但后续研究发现可通过再次短时烘干和拼配的方式加以改良。冻干抹茶无食品安全风险,而且于5℃保存1年后在绿度、内含物、微生物方面均基本保持稳定。所以,相较于传统生产模式,冷冻干燥技术加工的抹茶产品绿度更高。

Color is one of the important factors to measure the quality of Matcha.Nowadays,the steam,hot wind and other technologies could maximize the original green of tea,while the high temperature during the drying process will lead to the pigment oxidation and chlorophyll demagnification,which will result in the loss of the Matcha green degree.Three kinds of fresh tea leaves were selected for this experiment.After steam and hot wind sterilization,random samples were taken as the freeze-dried raw material.The mixed samples of ground tea of the same cultivar were used as the test control.The freeze-dried Matcha obtained by freeze-drying technology significantly increased the chlorophyll content and the greenness value by 13%~25%compared with the traditional drying methods,while the contents of amino acids,tea polyphenols and other components did not change significantly.Through the review,it was found that freeze-dried Matcha has the disadvantage of slightly green flavor.However,subsequent studies found that it can be improved by shorttime drying and matching again.Freeze-dried Matcha has no food safety risks.Moreover,its greenness,inclusion and microorganisms are basically stable after being stored at 5℃for one year.Therefore,freeze-drying technology can safely and healthily produce Matcha products with higher green degree than the traditional production mode.