13.

Simulated release profile of tartrazine dye adsorbed on BSY in gastric (A) and intestinal (B) environments. Experimental conditions: Samples containing 50 mL of tartrazine dye (10 mg·L^–1) and 0.1 g of dry BSY were prepared and incubated at pH 2 (25 °C) and pH 7 (37 °C) for 2 h. After centrifugation (5000g, 10 min), the precipitate was transferred to buffer solutions at pH 2 or 7 (HCl or KH₂PO₄) and incubated at 37 °C under agitation. Samples of 3 mL were collected at 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, and 120 min and analyzed at 425 nm to determine the release of the dye from the BSY.