Method for preparing theaflavin by recycling polyphenol oxidase

Abstract

The invention provides a method for preparing theaflavin by recycling polyphenol oxidase. The method comprises the following steps: 1) adding a polyphenol oxidase liquid and a tea liquid into a fermentation liquid; (2) introducing oxygen according to the amount of 0.5-2 units per minute, and performing fermentation for 40-150 minutes at a temperature of 20-40 DEG C at a rotating speed of 60-150 r / min; 3) performing filtration in an inert gas environment at a fermentation liquid temperature of 20-35 DEG C; and 4) purifying, concentrating and drying permeate to obtain theaflavin, wherein the polyphenol oxidase liquid returns to the fermentation liquid in the step (1) to participate in fermentation, so that the polyphenol oxidase liquid is recycled and the high-purity theaflavin is obtained.The polyphenol oxidase liquid is recycled, the activity of polyphenol oxidase is maintained, waste of polyphenol oxidase is avoided, the production cost of the theaflavin is greatly reduced, continuous production is facilitated, and safety and reliability are achieved.

Description

technical field [0001] The invention relates to a method for preparing theaflavins, in particular to a method for preparing theaflavins by recycling polyphenol oxidase, and belongs to the field of biotechnology. [0002] technical background [0003] Theaflavins (theaflavins, TFs) were first discovered by Roberts E.A.H (1957). It is a compound formed by the oxidation of polyphenols that can dissolve in ethyl acetate and is orange-yellow and has a benzotropolone structure. general term. There are 25 components of theaflavins whose structures have been clarified, the main components of which are: theaflavin (theaflavin, TF), theaflavin-3-monogallate (theaflavin-3-gallate, TF-3- G), theaflavin-3'-mono-gallate (theaflavin-3'-gallate, TF-3'-G) and theaflavin-3,3'-bis-gallate (theaflavin-3,3' -gallate, TF-3,3'-G) and epitheaflagallin-3-gallate (TF4), etc. The content of theaflavins in black tea is generally 0.3% to 1.5%. They are the main components of black tea and play a decis...

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Problems solved by technology

However, in the industrial production of theaflavins prepared by enzymatic oxidation, since polyphenol oxidase is not recovered and reused, after a single fermentation, in order to prevent theaflavins from being continuously Oxidation can only terminate the reaction for enzyme inactivation and passivation, which will cause waste of polyphenol oxidase, resulting in a 30-50% increase in production costs, and heat inactivation is often used for enzyme inactivation and passivation, and theaflavins exist The problem of poor thermal stability, thus causing the oxidative degradation of theaflavins, which has a low extraction rate

[0005] In the prior art of producing theaflavins by enzymatic oxidation, Chinese patents such as CN1155717C and CN02071232A, although the stability of the enzyme is better after immobilization, but the use of immobilized polyphenol oxidase to ferment theaflavins technology, there are still the following deficiencies: 1. In the stage of extracting and purifying polyphenol oxidase and immobilization, the activity of the enzyme is seriously lost, especially in the stage of enzyme immobilization, the activity of the enzyme after immobilization drops to about 50% of that before immobilization; Most of the solvents used to extract polyphenol oxidase are toxic acetone, which not only pollutes the environment, but also makes the product contain toxic solvents and affects its application, thus limiting the industrialization of theaflavins.

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