Abstract: Ultrasound-assisted biosorption of anthocyanins from blueberry pomace by waste beer yeast was investigated as a function of various processing parameters. The adsorption kinetics, isotherms and mechanism were determined, and the change of anthocyanin composition before and after adsorption was analyzed by high performance liquid chromatography (HPLC). It was found that the adsorption quantity of anthocyanins in the presence of ultrasound was significantly higher than that in the absence of ultrasound or with shaking (P < 0.05). The adsorption amount increased with the increase of adsorption time and the adsorption equilibrium was reached at 120 min. Furthermore, the adsorption amount increased with increasing ultrasonic intensity, temperature and initial concentration. The adsorption process was fitted to a pseudo-second-order kinetic model and the adsorption behavior could be well described by Temkin isotherm model. Fourier transform infrared spectroscopy results suggested that the amino, hydroxyl and amide groups on the yeast surface may play a key role in the biosorption of anthocyanins. HPLC analysis indicated that waste beer yeast could adsorb various anthocyanins to different extents. Overall, ultrasound can improve the adsorption efficiency of blueberry anthocyanins by waste beer yeast.

Key words: blueberry pomace, anthocyanins, waste beer yeast, ultrasound, biosorption