Optimization of supercritical CO2 extraction process for aroma compounds in green tea and composition analysis
2025
LI Guangcai | LU Xiaoshuang | ZHANG Mengcong | LIU Ailing | LIU Zhonghua | ZHANG Sheng
ObjectiveTo optimize the supercritical CO2 extraction process of green tea and clarify its aroma quality characteristics.MethodsYunnan Pu'er sun-dried green tea is used as the experimental material, and a single-factor experiment combined with response surface design is used to optimize the supercritical CO2 extraction process, so as to obtain the best process for extracting the aroma substances of green tea. The aroma compounds in supercritical CO2 extract of green tea are identified by solid-phase microextraction-full two-dimensional gas chromatography-time-of-flight mass spectrometry (SPME-GC×GC-QTOF-MS), odor activity value (OAV), and gas chromatography-olfactometry (GC-O).ResultsThe optimum process parameters are obtained as pressure of 21 MPa, extraction temperature of 50 ℃, extraction time of 2 h, CO2 flow rate of 21 L/h, and entrainer addition of 160 mL, and the extraction yield reaches 1.076 8% under such conditions. The supercritical extract of green tea is analyzed for identification of aroma compounds, and 81 aroma compounds are detected, including alcohols, terpenes, hydrocarbons, and esters, among which the content of alcohols is highest. Twenty-nine major aroma compounds with OAV values >1 are screened out, and 11 key aroma compounds such as geraniol and β-ionone are further identified by GC-O, which impart floral and sweet flavors to the supercritical extract of green tea.ConclusionEleven key aroma compounds, including geraniol, with different fragrance types, make significant contributions to the formation of the aroma in the supercritical extract of Yunnan Pu'er sun-dried green tea.
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