Preparation method of tea polyphenol of glechoma hedracea tea leaves

Abstract

The invention provides a preparation method of tea polyphenol of glechoma hedracea tea leaves. The preparation method comprises the following steps of: 1) picking fresh glechoma hedracea tea leaves, then freezing the glechoma hedracea tea leaves with liquid nitrogen, and immediately crushing the treated glechoma hedracea tea leaves to obtain a tea leaf crushed matter; 2) immediately adding the tea leaf crushed matter into water, the temperature of which is 70-90 DEG C, and then performing extraction by employing an ultrasonic-microwave synergistic extraction machine, wherein the extraction process parameters are as follows: the ultrasonic wave is 60-80W, the microwave is 30-400W, and the time is 20-60 minutes; 3) after extraction, performing cooling and centrifugal separation to obtain supernate containing tea polyphenol; and 4) performing reverse osmosis concentration on the supernate obtained in the step 3), and drying the supernate at normal temperature to obtain tea polyphenol extract powder of glechoma hedracea tea leaves. The method can obtain tea polyphenol which is relatively high in extraction rate without using an organic solvent.

Description

technical field [0001] The invention belongs to the technical field of tea extraction, and in particular relates to a method for preparing tea polyphenols from syringae tea leaves. Background technique [0002] Glechoma longituba (Nakai) Kupr., also known as Huoxuedan, Touguxiao, Tougufeng, Mandixiang, Jiangsu Desmodium, etc., is the dry aerial part of Huoxuedan, a perennial herb of Lamiaceae. Except for Northwest China and Inner Mongolia, it is distributed all over the country. Pungent in the mouth, slightly bitter, slightly cold in nature, enters liver, kidney, urinary bladder channel. It is good at promoting dampness and treating stranguria, clearing away heat and detoxification, dispelling blood stasis and reducing swelling. It is a commonly used medicinal material among the people, and is recorded in "Chinese Pharmacopoeia" (2010 edition). Clinically, it is mainly used to treat urolithiasis, hepatolithiasis, damp-heat jaundice and injury from falls, and has been used ...

AI Technical Summary

Problems solved by technology

[0003] The extraction process of tea polyphenols or catechins from tea leaves has formed production capacity: organic solvent extraction method; metal ion precipitation method and resin adsorption method. Among them, the metal ion precipitation method has high product purity, but the operation is complicated. The extraction rate is low, and it has been eliminated in the industry. Although the resin adsorption method has a high extraction rate and low energy consumption, the caffeine content in the product is high, and only crude tea polyphenols can be produced. Currently, in order to obtain tea polyphenols content> 98 %, tea polyphenols with caffeine content ≤ 3.0%, all adopt the leaching-solvent extraction method, the process of this method is simple to operate, and the yield is not low at 6-9%. The disadvantage is that chloroform or chlorinated organic compounds are introduced into the process Caffeine removal and ethyl acetate extraction process, the former is a toxic organic solvent, although acid solutions such as citric acid are also used to remove caffeine, but extraction with organic solvent ethyl acetate is inevitable

Ethyl acetate residues in the product will bring adverse effects on human health. If catechins are further purified as raw materials for medicines, the residues of ethyl acetate will have fatal effects