Analysis of Antioxidant Activity, Chlorogenic Acid, and Rutin Content of Camellia sinensis Infusions Using Response Surface Methodology Optimization

Optimization of the extraction process of green tea using response surface methodology (RSM) was performed. The optimized conditions were 14.91 min and 94.15 °C (2,2-diphenyl-1-picrylhydrazyl (DPPH) assay). The experimental values were close with the predicted values. The procedure was used to measure antioxidant activity using DPPH free radical and phenolic compounds of all types of Camellia sinensis and Tabebuia impetiginosa infusions. The antioxidant activity of infusions was in the order (mean for analyzed types) of pure green tea > white tea > green tea with additives > black tea = Pu-erh tea > semifermented tea > Red Lapacho. After the fermentation process, the content of rutin is lowered and the amount of gallic acid in infusions is increased. A negative correlation between total phenolic acids and organic acids was also observed (R 2 = 0.6437). Red Lapacho infusion contains phenolic acids such as caffeic, protocatechuic, p-coumaric, ferulic, and syringic. No rutin and quercetin were found in this beverage.