OPTIMIZATION OF POLYPHENOL EXTRACTION FROM AGED TEA LEAVES USING DESIRABILITY METHODOLOGY
Tóm tắt
In this study, polyphenol extraction from aged tea leaves was performed by water solvent. The tea extract was analysed for the content of total polyphenols by Folin-Denis method and the antioxydant activity of this extract was determined by DPPH free radical scavenging effect. Thus polyphenol extraction was optimized by using desirability methodology with experimental order of central composite orthogonal design (CCOD). Four main effective factors namely temperature, pH, solvent/material ratio (v/m) and extraction time were studied. The statistical analysis showed that in studied range the solvent/material ratio and temperature have had significant effects on extraction yield; meanwhile antioxydant activity was influenced by temperature, pH and solvent/material ratio. The optimal condition for polyphenol extraction was as followings: extraction time 42 minutes, pH 2.9, solvent/material ratio 10/1 (v/m) and extraction temperature 77oC. Extraction yield and antioxydant activity have reached 73.16%, 57.29%, respectively.
