Characterization and determination of the total polyphenols contents and the antioxidant activity in four types of yerba mate (Ilex paraguariensis St. Hill.) for preparing chimarrão

Abstract

Considering the wide use of the yerba mate leaves, and the benefits derived from them, the present study aimed at evaluating the quality of four kinds of native yerba-mate of chimarrão-type: traditional; specimens with addition of 5 % and 10 % of sugar; and thick ground sample. The homogeneity aspect was analyzed in three batches of products, corresponding to different weeks of processing. Also, the physicochemical properties, the total polyphenols contents and the antioxidant activity were evaluated. The aqueous extracts of yerba mate were prepared at 85 °C kept in decoction in a closed system, for 10 and 30 minutes. The yerba mate with sugar addition showed lower levels of mineral material and crude fiber, when compared with the traditional and the thick ground types. The thick ground kind of yerba mate wrapped in laminated package showed the lowest values of water activity in relation to other types of herbs wrapped in paper package. The laminated package also contributed to the low oxygen absorption delaying the oxidation of chlorophyll, maintaining the green coloration of the product. The extracts prepared from the thick ground kind of yerba mate, and those exposed to the longer decoction showed higher levels of total polyphenols.