Process for preparing tea polyphenol

Abstract

The invention provides a process for preparing tea polyphenol. The process comprises the following steps: (1) pretreating tea leaves: picking fresh tea leaves for spreading and airing, then carrying out enzyme deactivation on the tea leaves under microwaves by utilizing enzyme deactivation crushing equipment until the water content is 70-75%, and then crushing the standby tea leaves in a crusher to prepare tea powder for later use; (2) wall breaking: mixing the tea powder for later use with a citric acid aqueous solution according to the ratio of 1 kg of tea powder to (20-40) L, firstly performing microwave extraction, and then adding wood fiber hydrolase superfine powder for enzymolysis; then adding pectinase superfine powder and xylanase superfine powder for enzymolysis, and then performing boiling; and (3) extraction: extracting the enzymatic hydrolysate obtained in the step (2) for 10-15 minutes at the pressure of 0.5-0.8 MPa and the temperature of 90-100 DEG C in a reaction kettle, then performing extraction for 5-8 minutes at the ultrasonic power of 80-100 W, performing filtration to remove residues, centrifuging the filtrate, and collecting the supernate. The preparation process is simple, and the crusher provided by the invention can integrate fixation and crushing, and is automatic in operation and convenient and fast to use.

Description

technical field [0001] The present application relates to the technical field of tea polyphenol processing, in particular to a process for preparing tea polyphenols. Background technique [0002] At present, the traditional methods for preparing tea polyphenols from tea leaves are mainly divided into the following three categories: solvent extraction method, which impregnates tea leaves with polar solvents, then performs liquid-liquid extraction and separation of the leaching solution, and finally concentrates to obtain products. The current industrial production The yield of tea polyphenols in this method is 5% to 10%, and the product purity is 80% to 98%. The solvents used include acetone, ether, methanol, hexane and chloroform. pollution; the ion precipitation method uses metals to precipitate tea polyphenols to separate them from caffeine. This method uses heavy metals that are toxic to the human body as a precipitant. The products produced by this method are difficult t...

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Problems solved by technology

[0002] At present, the traditional methods for preparing tea polyphenols from tea leaves are mainly divided into the following three categories: solvent extraction method, which impregnates tea leaves with polar solvents, then performs liquid-liquid extraction and separation of the leaching solution, and finally concentrates to obtain products. The current industrial production The yield of tea polyphenols in this method is 5% to 10%, and the product purity is 80% to 98%. The solvents used include acetone, ether, methanol, hexane and chloroform. pollution; the ion precipitation method uses metals to precipitate tea polyphenols to separate them from caffeine. This method uses heavy metals that are toxic to the human body as a precipitant. The products produced by this method are difficult to meet the requirements of the food and pharmaceutical industries; the column separation preparation method mainly For gel column, adsorption column and ion exchange column method, the key of this technology is column packing and eluting

Studies have shown that the yield of tea polyphenols is between 4% and 8% and the purity can reach 98% by using the column separation preparation method, but the column packing material is very expensive, and many kinds and a large amount of organic solvents are used for rinsing. Not suitable for industrial production

The above traditional methods generally have some problems and disadvantages, and the products cannot fully meet the requirements of the food additives and pharmaceutical industries in terms of safety, price and purity

[0003] Prior art CN1482126A discloses a method for extracting tea polyphenols, including tea extraction, coarse filtration of tea water, ultrafiltration to remove pectin, nanofiltration or reverse osmosis dehydration and concentration, vacuum concentration, sprayer drying to obtain powdered tea extract, Under carbon dioxide supercritical fluid pressure 25-30MPa, temperature 35-50 ℃, water as auxiliary solvent, separation and analysis pressure 5-6MPa decompression separation, remove caffeine and extract tea polyphenols in powdered tea extract, no Tea extract is dissolved in ionized water, extracted with ethyl acetate, and high-purity tea polyphenols are obtained through desolvation and spray drying. The product purity is greater than 98%, the extraction rate is greater than 10%, and the caffeine is less than 0.1%. However, this invention uses supercritical CO2 extraction Technical equipment has high operating pressure, frequent switching, lack of design experience and effective design methods, sealing components cannot be used repeatedly, and there is no design and production standard for this kind of equipment in China, and large-scale standardized production is impossible, and there is too much tea in the extraction process Phenols are oxidized or structurally destroyed. Furthermore, if the tea leaves are not treated in advance, because tea contains natural polyphenol oxidase, the destruction of cells will lead to the release of polyphenol oxidase, which will affect the production and production of tea polyphenols. quality

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