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The Development of a Rotary Tea Roasting Machine and the Study of its Optimum Operation Conditions
|關鍵字:||Rotary;滾筒式;Tea Roasting Machine;Optimum Operation Conditions;焙茶機;最適操作條件||出版社:||農業機械工程學系||摘要:||
A rotary tea roasting machine was developed in order to improve the roasting operation. The operation variables of this new machine were roasting temperature（80℃、100℃、120℃）, time（2hr、4hr、6hr）, and weight（24㎏、36㎏、48㎏）. The response surface methodology was used to investigate the effects of operation variables on the product’s physical properties（moisture content, lightness, color difference, maximum shear force, bulk density and true density）, chemical property（total polyphenol content）and the sensory evaluation. And then, the optimum operation conditions of this new developed roasting machine were found.
The experimental results showed that：
1.Increasing the roasting temperature decreased the moisture content and maximum shear force of the product, but increased the color difference and total polyphenol content. However, the lightness and bulk density first increased and then decreased gradually with increasing roasting temperature.
2.Increasing the roasting time increased the color difference, bulk density and maximum shear force, but decreased the moisture content. Total polyphenol content decreased gradually then increased with increasing the roasting time. The roasting time did not affect the lightness of tea product.
3.Lift the roasting weight had not significant effects on the moisture content, bulk density, and true density, however, decreased the total polyphenol content.
4.Under the conditions of color difference<15.4NBS, maximum shear force<6.0N, total polyphenol content<136mg/g, the optimum operation conditions of this new developed tea roasting machine were found as roasting temperature between 86.61℃~101.04℃, roasting time from 3.13hr~4.16hr, and roasting weight between 34.43㎏~48.00㎏. Base on the machine performance and the convenience of the operator, the optimum operation conditions of this machine were recommended as roasting temperature between 90.0℃~100.0℃, roasting time from 3.5hr~4.0hr, and roasting weight between 34.5㎏~48.0㎏.
5.An experiment was taken to testify the responses of dependent variables under the optimum operation conditions. The results showed that there were no significant differences between the regression and experimental results for the color difference, maximum shear force, and total polyphenol content. The optimum operation conditions and the regression model developed were useful in this study. And this technique can be extended to the research of the tea product.
|Appears in Collections:||生物產業機電工程學系|
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