Effect of light intensity and processing conditions on bioactive compounds in maté extracted from yerba mate (Ilex paraguariensis A. St.-Hil.)

This is the first report investigating the effects of cultivation, growth under full sunlight (MSL) or shade (MS), and processing (drying, sapeco and roasting) on the composition and antioxidant potential of maté. Samples were roasted (180 °C, 200 °C, 220 °C or 240 °C) for a fixed time (10 min) or roasted (10, 20, 30 or 40 min) at a fixed temperature (200 °C). HPLC/UV/MS analysis and measures of total phenolic content (TPC) and antioxidant activity (2,2-diphenyl-1-picrylhydrazyl (DPPH) inhibition and soybean oil oxidation) were used to analyse phytochemicals. There were significant differences (p < 0.05, ANOVA/Tukey) in phenolics between MS and MSL samples following certain processing steps, but Principal Component Analysis (PCA) indicated no distinction between MS and MSL samples, suggesting that light intensity had no effect on phenolics. Caffeine increased significantly (p < 0.05) in MS samples. Temperature was more important than time, since pyrolysis of phenolics was more intense at 240 °C.