Optimization of Assaying Conditions about Condensed-Tannin in Cotton

This research was designed to discuss the optimal extracting condition of condensed tannin in cotton plant,the tannin was extracted by methanol-water or ethanol-water solvent,then the content of tannin was determined by vanillin colorimetry.Firstly,the best extracting condition of methanol or ethanol was obtained by single-factor experiments.Secondly,ethanol was chosen as a better extracting reagent by comparing the amount of condensed tannin in the best extracting condition of methanol or ethanol.Finally,the optimized extracting condition of ethanol was ascertained by orthogonal experiment,and it showed below: the ratio of material to solvent was 1∶20(g/mL),the concentration of ethanol was 40%(V/V),the time of ultrasonic-extracting was 30 minutes.