YERBA MATE PARTICLE SIZE INFLUENCE ON PHENOLIC COMPOUNDS AND ANTIOXIDANT ACTIVITY

The yerba mate (Ilex paraguariensis ST. Hill) is a widely grown plant in southern Brazil, Paraguay and Argentina. The plant has been the object of studies due to the high bioactivity related to several compounds such as phenols, methylxanthines, flavonoids and saponins. These compounds present high antioxidant properties which is attributed to health benefits. Its traditional consumption is in the form of chimarrão or tea, however, the extrability of these compounds and its activities can be influenced by the preparation process such as the particle size. The objective of this study was to evaluated the impact of yerba mate particle size on total phenolic compounds and antioxidant activity. The yerba mate leaves in nature were blanched and dried in a circulating oven. Afterwards, the blanched yerba mate were ground in a knife mill to reach particle sizes of ≤ 250 and ≤ 600 μm, named Fine Yerba Mate (FYM) and Coarse Yerba Mate (CYM). The total phenolic compounds (TPC) was measured by the Folin-Ciocalteau method and antioxidant capacity by the ABTS radical method. The smallest particle size presented TPC of 2256.66 ± 157.63 mg GAE 100 g-1 and inhibition of ABTS radical of 32254.09 ± 296.16 μM Trolox g-1, compared to 1672.65 ± 185.09 mg GAE 100 g-1 and 22837.62 ± 210.49 μM Trolox g-1 of TPC and ABTS, respectively, to CYM. The highest values for both TPC and antioxidant activity of FYM can be due to the larger contact area, allowing better phytochemical extraction. In conclusion, the particle size of yerba mate leaves is a crucial parameter for evaluation prior a application and development of new products with high functional compounds and activities.