Abstract: In order to effectively remove patulin from pear juice, the adsorption of attapulgite towards patulin in pear juice was studied. The adsorption isotherms were determined at different temperatures and the thermodynamics and kinetics of the adsorption process were analyzed. Besides, the changes in nutritional quality of pear juice before and after adsorption were examined. The results showed that increasing temperature in the range of 30–50 ℃ was conducive to the adsorption of patulin. The adsorption isotherms accorded with Freundlich equation (R2 > 0.99). The adsorption was a spontaneous endothermic process and the adsorbed patulin was not easily desorbed. At the same time, the adsorption kinetics conformed with the pseudo first-order kinetics model. Nutritional analysis showed that the contents of total acids, reducing sugar, soluble solids and total phenols as well as viscosity in pear juice decreased significantly (P < 0.05), while light transmittance and color values decreased at a slow rate during the adsorption process. The maximum and minimum rate of change in total acidity (46.96%) and light transmittance (2.64%), respectively were observed of the tested parameters when the adsorption was performed at 40 ℃ for 24 h at an initial patulin concentration of 3 μg/mL with the addition of 4.15 g/L of attapulgite. According to the static adsorption curves, the maximum adsorption efficiency of 70.57% was obtained after 24 h of adsorption at 40 ℃ with 4.15 g/L of attapulgite. Under these conditions, attapulalgite could reduce the content of patulin to the maximum extent.

Key words: attapulgite, adsorption, pear juice, patulin, quality