Method for preparing theaflavin with immobilized substrate

A method for preparing a theaflavin using an immobilized substrate, comprising:

• (1) mixing a tea polyphenol solution with an inert adsorption carrier and conducting adsorption to obtain an adsorbed material, and subjecting the adsorbed material to water-washing and alcohol-washing in sequence to obtain an immobilized substrate, wherein the inert adsorption carrier comprises a macroporous adsorption resin;
• the macroporous adsorption resin has a pore size of 10 Å to 180 Å;
• and an alcohol solution for the alcohol-washing has a concentration of 4 wt % to 20 wt % alcohol;
• (2) mixing the immobilized substrate with an enzyme solution, and conducting an enzymatic reaction by introducing oxygen to obtain an enzyme-catalytic carrier, wherein an enzyme in the enzyme solution is polyphenol oxidase (PPO);
• and
• (3) subjecting the enzyme-catalytic carrier to desorption to obtain an eluate, and concentrating the eluate to obtain the theaflavin.