Abstract:  An assay method was established for thedetermination of total catechins, the major functional component of tea, inbread made with ultrafine green tea powder as an ingredient. The method was optimizedwith a 3-factor (i.e., solid-liquid ratio, extraction temperature, and extractiontime) and 3-level orthogonal experiment for the 95% ethanol extraction prior toa colorimetric measurement after the sulfuric acid-vanillin reaction. The optimizedethanol extraction was conducted under a solid-liquid ratio of 1:20 (g·mL^-1) in a 70℃water bath for 45m. Subsequently, 0.5 mL of the extract were added with 2.5mL each of 1% vanillin and 30% sulfuric acid ethanol solutions to stand at 20℃ for 10～30 min. Spectrophotometricabsorbance at 500 nm of the reaction solution was obtained. The readings werefound correlated linearly with the standard catechins concentrations in therange of 0.025～0.3 mg·mL^-1 with a R² of 0.9996. The RSD of 6 replicates measured by thenew method was 1.31%. And, the catechins recovery at high-to-low concentrationsranged from 98.75% to 103.25%. The method appeared appropriate for the totalcatechins determination in bread containing green tea.