Abstract: Microencapsulation is an effective method to protect biologically active materials from the damage by environmental factors. Yeast cells are natural and edible microencapsules. In the present study, yeast cells were pre-treated by alcohol, 3% sodium chloride, alkaline protease and sodium hydroxide to obtain ACY, AEY, AY and AWGP, respectively. The treated yeast cells were used to adsorb tea polyphenols in aqueous solution. The results indicated that the absorption rates of tea polyphenols in 4 kinds of pre-treated yeast cells such as ACY, AEY, AY and AWGP with the addition of 2.00 g tea polyphenols were 98.1%, 94.3%, 93.2%, and 73.2% under the conditions with absorption time of 4 h, absorption temperature of 40℃, and tea polyphenol solution at pH 4.0. The adsorption capacities of ACY, AEY, AY and AWGP on tea polyphenols were 319.8, 307.4, 303.8 mg/g and 238.5 mg/g, respectively. Adsorption kinetics analysis showed that four kinds of pre-treated yeast cells were in accordance with Langmuir and Freundlich isotherm models. Antioxidant experiments confirmed that yeast cells could function as the role of microencapsules.

Key words: yeast cells, tea polyphenols, adsorption, microencapsules