School of Mechanical & Automotive Engineering, South China Univ. of Technology, Guangzhou, 510640, China.
J Food Sci. 2010 May;75(4):C363-8. doi: 10.1111/j.1750-3841.2010.01604.x.
Low-caffeine or caffeine-removed tea and its products are widely welcomed on market in recent years. In the present study, we adopt ultrasonic-enhanced supercritical fluid extraction process to remove caffeine from green tea. An orthogonal experiment (L16 (4(5))) was applied to optimize the best removal conditions. Extraction pressure, extraction time, power of ultrasound, moisture content, and temperature were the main factors to influence the removal rate of caffeine from green tea. The 5 factors chosen for the present investigation were based on the results of a single-factor test. The optimum removal conditions were determined as follows: extraction pressure of 30 MPa, temperature at 55 degrees C, time of 4 h, 30% moisture content, and ultrasound power of 100 W. Chromatogram and ultraviolet analysis of raw material and decaffeinates suggests that under optimized conditions, the caffeine of green tea was effectively removed and minished without damaging the structure of active ingredients in green tea.
近年来，低咖啡因或无咖啡因茶及其制品在市场上广受欢迎。在本研究中，我们采用超声强化超临界流体萃取工艺从绿茶中去除咖啡因。采用正交实验（L16 (4(5)))优化最佳去除条件。萃取压力、萃取时间、超声功率、含水量和温度是影响绿茶中咖啡因去除率的主要因素。本研究选择的 5 个因素是基于单因素试验的结果。确定的最佳去除条件如下：萃取压力 30 MPa，温度 55°C，时间 4 h，含水量 30%，超声功率 100 W。原料和脱咖啡因的色谱和紫外分析表明，在优化条件下，绿茶中的咖啡因被有效去除和减少，而绿茶中有效成分的结构没有受到损害。
