評估水活性檢測做為中藥材含水程度之指標

Evaluation of Water Activity as an Indicator for the Moisture Content of Chinese Herbal Medicine

林雅如(Ya-Ju Lin)

指導教授 ： 蔡東榮

高雄醫學大學/藥學院/藥學研究所碩士在職專班/碩士(2007年)

摘要

本研究的目的希望能建立準確而可信的中藥材等溫吸濕方程式，開發一個可快速估算中藥材水分含量的方法。中藥材乾燥減重試驗費時至少5小時；而採用水活性檢測，透過等溫吸濕曲線方程式以估算藥材水分含量只需5-10分鐘，極具經濟效益。
由市場取得中藥材檢體共39種195件檢體，藉此暸解市場中藥材之乾燥減重值與水活性值的分布趨勢；建立其中4種常用藥材之等溫吸濕曲線及方程式，以計算藥材理論之適當水含量；再以市場中藥材水活性實測值，透過方程式換算水分含量，再藉由計算市售藥材之乾燥減重值與方程式水分含量估算值之偏差程度，以評估水活性檢測做為中藥材含水程度之指標的可行性。
乾燥減重試驗係將藥材置105℃乾燥 5小時，乾燥至恆量，計算檢品之乾燥減重百分率。水活性檢測則採用冷卻鏡露點法（AOAC method 978.18），設定溫度於 25 ± 0.5℃，時間5-10分鐘，直接讀取數值。
結果顯示市售中藥材水活性值低於0.65之比例約53.8%，超過0.65的比例約46.2%，可見約半數之市售中藥材可能有發霉變質之虞；市場品之乾燥減重值分布範圍極大，似無規律可言。
藉由方程式計算之適當水分含量與藥典規格值比較發現，藥典規格值多落於藥材適當水分推論範圍內，可見推得之適當水分含量可以作為乾燥減重規格值設定之參考。以水活性實測值透過方程式，求得之水分含量與中藥材乾燥減重實測值進行比較，結果顯示藥材乾燥減重值與估算之水分含量之偏差低於10%。本研究結果認為以水活性檢測作為中藥材含水程度之新指標，的確具有相當之可行性，值得更多、更深入地研究。

關鍵字

水活性 ； 乾燥減重 ； 中藥材 ； 等溫吸濕曲線

並列摘要

The purpose of this research is to develop a method with accurate and feasible equation of moisture sorption isotherm (MSI) in order to rapidly calculate the moisture content in Chinese herbal medicine. The time of the loss on drying test of Chinese herbal medicine is needed not less than 5 hours. It is more economical for the time of the water activity test and got the moisture content from the equation of MSI is just needed 5-10 minutes.
We take samples of all 195 traditional Chinese herbs of 39 different species and attempt to determine the distribution tendency of the result of loss on drying and water activity. Furthermore, we will attempt to establish the MSI and equations of four commonly used Chinese herbal medicine. After an appropriate equation is developed, we wish to estimate a rationed level of water content for the various Chinese herbal medicine on the market, observe the deviation between the true and estimated values, and evaluated the water activity values as the rational index of the water content for Chinese herbal medicine.
In order to determine the loss on drying, we will keep the herbs at 105℃for five hours, dry to the constant weight, and then calculate the percentage of loss on drying. The water activity test uses the chilled- mirror dew point method (AOAC method 978.18), temperature is 25 ± 0.5℃, for five to ten minutes read the water activity value directly.
The result showed the water activity values of 53.8% of the herbs in the market below 0.65, and 46.2 % of them are above 0.65, it means about half of herbs in the market make mildew a possibility. The distribution of the loss on drying values of herbs in the market are broad, seems no rules to obey.
The comparisons of the equation estimated water content and the specification of pharmacopoeia indicate the specification of pharmacopoeia is under the range of estimated rational level of water content. Estimated rational water content is appropriate to be reference for setting the specification of the loss on drying. The moisture content got from the water activity of the equation of MSI, carries on the comparison the loss on drying of herbs. The result showed that the deviation of the loss on drying values of Chinese herbal medicine and the estimated moisture content is not more than 10%. The conclusion of this study is water activity to be a new indicator about assessing the moisture content in Chinese herbal medicine has quite the feasibility, and it is worth doing more deep researches.

並列關鍵字

Water activity ； Loss on drying ； Chinese herbal medicine ； moisture sorption isotherm

參考文獻

1. 孟憲紓，中成藥分析，人民衛生出版社，1998，pp.58-60，中國北京。

2. 闞建全，食品化學，新文京出版社，2006，台灣台北。

3. 行政院衛生署中華藥典編修小組，中華藥典第五版補篇(中藥集)附錄，行政院衛生署編印，2003，pp.15-16，台灣台北。

4. 日本公定書協會監修，第十四次改正日本藥局方解說書 v.1-4，廣川書店，2001，日本東京。

5. 國家藥典委員會編，中華人民共合國藥典2005年版一部，化學工業出版社，2005，中國北京。