以非酵素性褐變反應為基礎開發時間溫度指示劑

Abstract

在過去數十年間，時間溫度指示劑（TTI）的領域有了重大的進展，化學型TTI是一個便利的裝置用於紀錄食品在冷鏈系統中的熱歷程，並可推算貨架期。雖然此類型的TTI 可以提供直觀且視覺化的資訊，但在食品供應鏈的實務應用上，仍有許多問題存在，包括價格高與具有毒性等。本研究旨在利用沒食子酸之非酵素性褐變反應，開發低價且無毒性的化學型TTI。此裝置在pH 值範圍6.5–8 且保藏於等溫範圍5℃至50℃下的顏色變化，可藉由紫外光/可見光分光光譜儀以最大吸收波長420 nm 進行量測。非酵素性褐變反應之反應速率及活化能適合以阿瑞尼斯方程式進行計算。研究結果顯示，沒食子酸在高pH 值及高溫下不穩定，使得非酵素性褐變反應的速率增加，顏色變深。此裝置的反應符合一級反應，在不同的反應條件（pH 值與溫度）下，由阿瑞尼斯方程式計算之反應速率為0.018 至0.7135 min-1，活化能為11.98 至14.87 kcal/mol。由沒食子酸的活化能可知，此材料具有潛力可以開發出良好的化學型TTI，應用於監控食品於運送及儲藏過程之品質變化並預測貨 架期。

Over the past several decades significant developments have taken place in the field of time-temperature indicator (TTI). A chemical type TTI is a convenient device designed for recording thermal history that could be used to predict food shelf life throughout the cold chain. Although this type of TTI can provide intuitive and visual information about food quality, there are still several problems occurred when it used in food supply chain, including high cost and toxicity. The aim of this study is to develop a low cost and nontoxicity chemical type TTI based on the non-enzymatic browning reaction carried on gallic acid. The color change of the device storage at constant temperature from 5℃ to 50℃ and pH in the range 6.5-8 was studied with the aid of UV-VIS spectroscopy at 420 nm. The rate constant and activation energy of non-enzymatic browning was well expressed by Arrhenius equation. The result showed that gallic acid is not stable at high pH and high temperature cause the non-enzymatic browning reaction rate increase and the brown color intense. The reaction obey first order reaction. By Arrhenius equation calculated, the rate constant varied from 0.0018 to 0.7135 min-1 and activation energy of the device was 11.98 to 14.87 kcal/mol in different conditions (pH and temperature). Since activation energy of the non-enzymatic browning reaction of gallic acid, it has potential to develop an optimal chemical type TTI for monitoring the quality changes of food and matching the shelf life during the distribution and storage.