Effect of different brewing times on antioxidant activity and polyphenol content of loosely packed and bagged black teas (Camellia sinensisL.)

Objective: Determination and comparison of the effect of infusion time on the antioxidant activity and total polyphenol contents of bagged and loosely packed black teas. Materials and Methods: For twenty loosely packed and eleven bagged tea sles, the antioxidant activity and total polyphenol content were analyzed using FRAP and FolinCiocalteau methods, respectively. The ANOVA with Tukey posthoc test and independent ttest were used for statistical analysis. Results: The antioxidant activity and polyphenol content of various brands of tea sles were significantly different. There were significant differences in the antioxidant activity of loosely packed teas between 5, 15(p=0.03), 30(p=0.02) and 60(p=0.007) minutes of brewing times. Besides, there was a significant difference in antioxidant activity of bagged sles infused for 1 minute with four other infusion time points (p<0.001). In the case of polyphenol content, in looselypacked tea sles, there were not significant differences between different brewing times (p=0.15). However, in bagged sles, the polyphenol contents of sles that were brewed for 1 minute were significantly lower than sles brewed for 3, 4, and 5 minutes (p<0.05). The antioxidant activity and polyphenol content of tea bags were significantly higher than those oflooselypacked forms of the same brands at 5min of brewing time (p<0.001). Conclusion: The infusion time and the form of tea (loosely packed or bagged) were shown to be important determinants of the antioxidant activity and polyphenol content of black tea infusions in addition to the variety, growing environment and manufacturing conditions.