Screening of Plant-derived Polyphenol Oxidase for the Formation of Theaflavins and Theasinensins from the Oxidation of Catechins

Objective:To find the plant-derived PPO which can oxidize catechins to form TFs and TSs efficiently. Methods:Fengshui pear,Gong pear,Xiang pear,Hongfushi apple,tea fresh leaves and laccase were selected as the tested materials to study the PPO activity of different source. Effects of the PPO from Fengshui pear,Hongfushi apple,laccase on the synthesis of TFs and TSs from catechins were analysed. Results:The PPO in Fengshui pear had the highest activity which was 621.4 U/(min·g),approximately 2.8 times of that in fresh tea leaves. The ability to synthesis of TFs was Fengshui pear > Hongfushi apple > laccase. And concentrations of TFs were 0.228,0.011 and 0.008 mg/mL,respectively. TF-3'-G and TFDG were the major oxidation production with PPO of Fengshui pear. However,the other two PPO were contributed to the formation of TF. Meanwhile,the ability to synthesis of TSs was Fengshui pear > laccase > Hongfushi apple. And the concentrations of TSs were up to 0.958,0.158 and 0.100 mg/mL,respectively. The Fengshui pear PPO was contributed to the formation of TSA,TSB,while the other two PPO were contributed to the formation of TSA,TSC. Under the catalysis of three kinds of enzymes,the concentrations of TSs were all higher than TFs. Conclusion:The PPO in Fengshui pear had the stronger ability to synthesis of TFs and TSs than PPO from Hongfushi apple and laccase.