Abstract
The lack of aroma and natural taste is a critical problem in production and consumption of instant green teas. A method to prepare instant green teas high in-natural-aroma and low-caffeine by the novel column chromatographic extraction with gradient elution is reported. This method simultaneously extracted aroma (or volatile) and non-aroma compounds from green tea. Green tea was loaded into columns with 2.0-fold of petroleum ether (PE): ethanol (8:2). After standing for 3 h until the aroma compounds dissolved, the column was sequentially eluted with 3.0-fold 40% ethanol and 3.5-fold water. The eluant was collected together and automatically separated into PE and ethanol aqueous phases. The aroma extracts was obtained by vacuum-evaporation of PE phase at 45 °C. The ethanol aqueous phase was vacuum-concentrated to aqueous and partially or fully decaffeinated with 4% or 9% charcoal at 70 °C. A regular instant green tea with epigallocatechin-3-gallate: caffeine of 3.5:1 and a low-caffeine instant green tea (less than 1% caffeine) with excellent aroma and taste were prepared, by combining the aroma and non-aroma extracts at a 1:10 ratio. This work provides a practical approach to solve the low-aroma and low-taste problems in the production of high quality instant green teas.
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Acknowledgements
This work is supported by the Guangdong Provincial Science and Technology Programs (No. 2014A010107026 and No. 2013B020503069), China Central Government Agricultural Technology Promotion No. 2015-60-43, the Natural Science Funds of Guangdong Province (Program 2014A030313423), the Special Research Fund for University Ph. D Programs (No. 20134407120004) and the Guangdong Special Funds for Development of Science and Technology Innovation of University Students (Program No. pdjh2015b0146).
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Li, QR., Wu, M., Huang, RJ. et al. Extraction and preparation of high-aroma and low-caffeine instant green teas by the novel column chromatographic extraction method with gradient elution. J Food Sci Technol 54, 2186–2192 (2017). https://doi.org/10.1007/s13197-017-2655-z
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DOI: https://doi.org/10.1007/s13197-017-2655-z