微波对茶叶中霉菌的灭菌效果研究

Study on sterilizing effect of microwave on tea moulds

为解决茶叶中霉菌的污染问题 ,研究了不同微波条件对茶叶中霉菌的杀灭效果 ,以达到在茶叶加工中综合利用微波实行加热制作和杀除霉菌的双重目的。试验结果表明 :微波对茶叶中霉菌的处理效果随茶叶水分含量的增加而增强 ,同时与茶叶的处理物料量、容器介质及水分扩散条件有关。使用 80 0W功率的微波炉 ,处理 135s ,可将 2 5 0g茶叶中的霉菌完全杀灭。处理 12 0s ,可将鲜茶料和发酵茶料中的霉菌完全杀灭。轻度的微波作用对茶叶中霉菌生长有激活效应 ,微波加热超过 15 0s ,会对茶叶本身的品质造成损害。在茶叶的初制加工过程中 ,进行微波处理 ,可有效地控制茶叶中的霉菌 ,同时实现对茶叶料的热烘干。

Moulds have been a long standing hazardous problem in food industry because it produces harmful mycotoxins. How to control moulds in the processing of tea has been a difficult technical problem for a long time. This work studied the mould preventing effect of microwave treatment on tea products and their controlling conditions. It was shown that the microwave sterilizing treatment grew more effective with the increased moisture of the tea. And the effect is also related to the quantity of tea treated, the material of container and the diffusion of water. An 800?W microwave oven killed all the moulds in 250?g tea within 135 seconds and in 250?g fresh or fermented tea within 120 seconds. Conversely, slight microwave heating augmented the growth of moulds in tea. A microwave treatment over 150 seconds harmed the quality of the tea. It was concluded that microwave treatment in the preliminary processing of tea can effectively control the growth of moulds, and at the same time dry the products. The conditions in which moulds are under control in the processing of tea with microwave are also discussed here.