Improvement of the water brewing of Vietnamese green tea by pretreatment with supercritical carbon dioxide

Raw material Vietnamese green tea leaves were processed by different procedures involving supercritical carbon dioxide flow and periodical decompressions of high pressure CO2, in order to determine their influence on the extraction of active components by water phase during tea brewing. Several thermodynamic characteristics of supercritical fluid CO2 decaffeination of Vietnamese green tea are reported as a function of temperature and pressure. The imbibition of green tea leaves in supercritical CO2 conditions intensifies mass transfer of active components of green tea in water brewing, an optimal combination of degree of tea leaf quality preservation, low prime cost and good profitability.