Study On Tea Flower Extracts By Super-critical CO₂and Its Functional Properties Research

In this paper, supercritical CO₂was employed to extract tea flower and response surfacemodel was used to optimize the processing parameters of extraction. GC-MS was alsoemployed to compare the components and contents of tea flower extracts by supercritical CO₂,subcritical CO₂and petroleum ether medium. The extracts by supercritical CO₂extractionwere microcapsulated by β-cyclodextrins under the optimized conditions. The abilities ofanti-hyperlipidemic and anti-oxidation of the extracts were also compared.The factors that affect the yield of extracts were determined by single–factor experimentprior to multi-factor optimization experiment via response surface methodology. Theoptimized parameters for the supercritical CO₂extraction were as followings:35MPa;48℃;43%of co-solvent （w/w）. The yield under these conditions was reached about2.785%±0.068%.The components of the extracts from tea flower via supercritical CO₂, subcritical CO₂and petroleum ether mediums individually were detected and compared with GC-MS. Theresults showed that the main components of the three extracts were basically the same, butdifferent in quantity. All the extracts were found containing58components involved in10categories, specifically17kinds of aliphatic and aromatic hydrocarbon,7esters,7acids,6terpenol and terpenone,6aliphatic ketones,5terpenes,4aromatic alcohols and aromaticketones,2aliphatic alcohols,2aldehydes, and2other compounds. Extracts by supercriticalCO₂had the highest contents of acetophenone, phenethanol, α-phenethanol, linalool oxide incontent, which were the key odorant of tea flower. With the method of principle componentanalysis by SPSS, two principle components were identified. Component1was thecomponents those are relevant to the key odorant, and component2was the components thoseare irrelevant to the key odorant.Microcapsulation of the supercritical CO₂-extracts was carried out with β-cyclodextrinsas the embodier. The microcapsulation was evaluated by elctron microscopy, FTIR and X-raydiffraction. The optimal parameters for the microcapsulation were as followings: wall/coreratio11:1; microcapsulation temperature53℃; microcapsulation time140min. The inclusionembeded rate reached about83.585%±0.084%under the optimized conditions.The tea flower extracts by supercritical CO₂extraction and ethanolic extract residues hadthe greatest adsorption rate to sodium taurocholate and sodium glycocholate when theconcentration was32mg/mL （highest）. The residues extracts with ethanol had similar adsorption rate to the two bile salts with cholestyramine, but higher than the extracts bysupercritical CO₂extraction; the clearance rates of DPPH radical, superoxide anion andhydroxide radical did not differ much between the residues extracts with ethanol and BHT,and both are higher than extracts by supercritical CO₂. The clearance rates of radical wasincreasing with the concentration of samples.