Abstract:

This study aimed to establish a phenol-sulfuric acid method for the determination of the polysaccharide content
in green tea and evaluate its performance in comparison with that of the anthrone-sulfuric method. In the phenol-sulfuric
acid method, three experimental conditions including phenol concentration, sulfuric acid dosage and color development time
were optimized by single factor experiments and response surface methodology using absorbance value as the dependent
variable. A mathematical regression model was established. The optimum experimental conditions were found as followes:
1 mL of 4.8% aqueous phenol solution, 5 mL of concentrated sulfuric acid, and detection at 488 nm after 29 min of color
development. There was a good linear relationship between absorbance and concentration in the range from 0 to 0.2 mg/mL.
The experimental results showed that the average recovery rate was equal to or higher than 97.55% with good reproducibility
(RSD = 1.82%, n = 7). The phenol-sulfuric acid method was rapid, accurate, sensitive and suitable for the determination of
polysaccharide in green tea.

Key words: tea polysaccharide, phenol-sulfuric acid method, anthrone-sulfuric method, response surface methodology