Adsorption and Flocculation Effect of Attapulgite on Water Extract of Stevia Leaves

OBJECTIVE To study the adsorption and flocculation effect of attapulgite(ATP) on water extract of stevia leaves. METHODS The factors influencing adsorptive and flocculate properties of ATP such as the temperature, pH value, the concentration of the water extract of stevia leaves and the amount of ATP addition were investigated by single factor experiment and orthogonal experiment. RESULTS The optimum condition abtained were 60 ℃ temperature and pH 8, respectively, and the addition of ATP was 0.4 g for 30 mL water extract. The adsorption method of ATP showed the higher retention rate of rebaudioside A (92.2%) and solids (70.5%) than the chemical ones (62.6% and 57.3%, respectively). CONCLUSION ATP can be used as a new flocculant for isolation and purification of Chinese herb extracts.