真空乾燥及低溫沸騰技術開發與應用

Development and Applications of Vacuum Drying and Low Temperature Boiling

蔡順德(Shun-Te Tsai)

指導教授 ： 陳恕行

崑山科技大學/工程學院/機械工程研究所/碩士(2012年)

摘要

傳統的茶葉製作過程中,須經由日光委凋以去除部分水份,然而若氣候狀況不佳,溫度過高或過於乾燥,往往容易影響委凋效果,造成委凋時間無法確實掌握,且由於傳統的乾燥製作過程屬熱風乾燥方式,通常是將高溫空氣接觸茶葉表面,使茶葉內水份不斷的蒸發脫水,以達到乾燥的目的,然而茶葉的香氣主要是在製茶過程中產生,熱風所產生的高溫空氣,會使茶葉中所蘊含的揮發性成分茶葉水份一併蒸發而消失,且其高溫乾燥會破壞茶葉的茶綠素,或造成茶葉過焦,使實用時會感覺到焦味、苦澀,造成茶葉原味喪失,影響整體茶葉的品質。
傳統的乾燥方式一般為除濕機、空調、低溫乾燥或熱風乾燥，然而都是由外而內乾燥去除水份,往往需要控制的非常精準，否則容易造成茶葉變質、變形或過焦，使表面雖已乾燥而其內部仍含有水分，無法完全達到乾燥效果，或也有採用遠紅外線、高調波、低調波、微波乾燥方式，雖然以達到由內而外的乾燥效果，但都是以升溫方式去除水份，其高溫仍會造成影響茶質好壞的重要因素，以上所述的種種缺陷，確有待改良的必要性。
為解決前述問題，本實驗研究目的在於提供一種茶葉水份乾燥奈米化成型方法及裝置，其主要利用真空乾燥方式，以在製作過程中輔助或取代傳統的熱風乾燥方式，利用真空乾燥的低溫低壓條件，利用負壓狀態使水分膨脹且沸點降低，避免如傳統製作過程因高溫而破壞茶質,且其可使水分細小化以增加水分輸出，確實提高乾燥效果，可有效保留茶葉的葉綠素與茶香，使產品達到品質 佳並可提昇其利用性與實用價值。

關鍵字

真空乾燥 ； 酵素褐變 ； 低溫沸騰 ； 低溫冷凍

並列摘要

Traditional tea production process, subject to the Commission by the sun withered to remove part of the water, however, poor weather conditions, the temperature is too high or too dry, they often influence the effect of Commission withered, resulting in withered Committee can not really grasp, and because dry production process is a hot air drying method, usually the high-temperature air contact with the tea surface moisture evaporation in the tea dehydration, in order to achieve the purpose of drying, however, the aroma of tea in the tea production process, hot air together with evaporation of high-temperature air, and make tea contains volatile components of tea water and disappeared, and its hot and dry will destroy the tea, green tea pigment, or cause the tea burnt, so that practical when you feel burnt smell, bitter, resulting in the loss of tea flavor, affecting the overall quality of tea.
And wherein, the traditional drying method is generally dehumidifiers, air conditioning, low-temperature drying or hot air drying, however, are from outside to dry to remove water, often require very precise control, or likely to cause the tea deterioration, deformation or burnt the surface Although dry while still contained within the water, unable to fully meet the drying effect, or using far infrared, high-profile, low-key, microwave drying, in order to achieve the drying effect from the inside out, but they are warming way to remove water, the high temperature will cause an important factor affecting the quality of tea quality, and above all the defects, and indeed the need to need to be improved.
To solve these problems, the experimental study aims to provide a tea water dry nano-molding method and device, the main use of vacuum drying method, and to complement or replace traditional hot air drying method in the production process, the use of vacuum drying low temperatures low-pressure conditions, the use of the vacuum state so that the moisture expansion and the boiling point lower, to avoid the destruction of the tea quality such as the traditional production process due to high temperatures, and small allows water to increase water output has really improved drying effect, which can effectively retain tea chlorophyll tea, to achieve good quality and will increase its use and practical value.

並列關鍵字

vacuum drying ； enzyme browning ； low boiling ； freezing

參考文獻

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