Extraction and Removal of Caffeine from Green Tea by Ultrasonic-Enhanced Supercritical Fluid |
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| Authors: | Wei-Qiang Tang Di-Cai Li Yang-Xiao Lv Jian-Guo Jiang |
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| Affiliation: | 1. Authors Tang and Lv are with School of Mechanical & Automotive Engineering, South China Univ. of Technology, Guangzhou, 510640, China. Authors Li and Jiang are with College of Food and Bioengineering, South China Univ. of Technology, Guangzhou, 510640, China. Direct inquiries to authors Tang and Jiang (E-mails: wqtang@scut.edu.cn;2. jgjiang@scut.edu.cn). |
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| Abstract: | ABSTRACT: 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 (45)) 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 °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. |
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| Keywords: | caffeine extraction green tea supercritical fluid ultrasonically enhanced |
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