This study aimed to assess the influence of time and sodium sulfite concentration on tannin yield in Curupay bark and propose better extraction conditions. The extractions were performed using 100 g of dried bark and 1500 mL of water at 70 °C, with extraction times of 2, 3, and 4 h and amount of extractor salt at the concentrations of 0, 1, 2, 3, and 4%. The following parameters were evaluated: content of total solids, total yield of solids, Stiasny index, and gravimetric yield of condensed tannins and non-tannins. Results show that the higher the concentration of sodium sulfite, the higher the content and yield of solids, as well as the higher the extraction of non-tannin compounds. Three-hour extraction time at 3.0% sodium sulfite concentration was the best condition to extract tannins from Curupay bark, under which a condensed tannin yield of 20.46% was obtained.
