Total polyphenol content and perceived astringency of yerba mate "ilex paraguariensis" infusions

The relation of total polyphenol content and dynamical astringency was investigated on infusions of yerba mate (YM) (Ilex paraguariensis St. Hilaire), a mild stimulant beverage habitually consumed in South America. YM is a heterogeneous mixture of leaves and small sticks giving place to the types with sticks (YM-S) and without sticks (YM-L) according to the composition. Phytochemical and sensory analysis on three brands of each YM type were performed in order to know if there are differences between types and among brands of the same type. Total polyphenol content, determined by spectrophotometry in six YM infusions at 5% w/v, showed that chlorogenic acid levels were higher for two brands of the YM-L type. Time-intensity (TI) curves revealed that infusions prepared with YM-S lowered their maximal perceived astringency. Neither the type nor the brand of YM assessed affected temporal parameters of astringency TI curves.