CN-122004319-A - Tibetan tea insoluble dietary fiber and extraction method thereof

CN122004319ACN 122004319 ACN122004319 ACN 122004319ACN-122004319-A

Abstract

The invention provides Tibetan tea insoluble dietary fiber and an extraction method thereof, wherein Tibetan tea powder is subjected to cold ball milling-low temperature plasma gas phase modification synergistic pretreatment, a compact cell wall structure is destroyed, the hydrophilicity of the tea powder is improved, then multienzyme sequential enzymolysis is carried out under the assistance of an alkyl glycoside-chitosan/graphene quantum dot compound, the graphene quantum dot in the compound can permeate and expand holes, the alkyl glycoside can expand a fiber structure and protect enzyme activity, the chitosan can adsorb impurities, the inhibition effect of polyphenol on the enzyme is effectively overcome, and the enzymolysis efficiency and the impurity removal effect are improved. The invention obviously improves the extraction purity and the yield of the Tibetan tea insoluble dietary fiber through the synergistic effect of physical wall breaking and functional compound auxiliary enzymolysis, and provides a new way for the high-value utilization of Tibetan tea resources.

Inventors

CHEN HONG
Zhong Xiushuang
LI PANPAN
LI PENG
Zhou Digang
LI CHAOGUI

Assignees

四川农业大学
雅安茶厂股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260331

Claims (10)

1. The extraction method of the Tibetan tea insoluble dietary fiber is characterized by comprising the following steps of: S1, crushing Tibetan tea, sieving to obtain Tibetan tea powder, mixing the Tibetan tea powder with zirconia balls to obtain a mixture, adding the mixture into a freezing ball milling tank, adding absolute ethyl alcohol, sealing, freezing and ball milling to obtain ball-milled tea powder; S2, transferring the ball-milled tea powder to a low-temperature plasma gas-phase modification cavity, introducing argon-oxygen mixed gas, treating for 3-4min, purging with argon, taking out the tea powder, degreasing, and drying to obtain pretreated tea powder; s3, mixing the pretreated tea powder with water, uniformly stirring to prepare tea slurry, adding the alkyl glycoside-chitosan/graphene quantum dot compound, and uniformly stirring at room temperature to obtain slurry; S4, regulating the pH of the slurry to 6.5 by using 1mol/L NaOH, adding alpha-amylase, carrying out enzymolysis for 1.5-2 hours at 55-65 ℃, regulating the pH to 4.5,55-65 ℃, adding saccharifying enzyme for enzymolysis for 0.5-1.5 h, regulating the pH to 7.0 again, adding neutral protease, carrying out enzymolysis for 1.5-2.5 h at 60-70 ℃, inactivating enzyme, centrifuging, collecting precipitate, washing and drying to obtain the Tibetan tea insoluble dietary fiber.
2. The method for extracting insoluble dietary fiber from Tibetan tea according to claim 1, wherein the Tibetan tea comprises banker, strip tea, tender stem and red moss.
3. The extraction method of Tibetan tea insoluble dietary fibers according to claim 1, wherein the mass ratio of Tibetan tea powder to zirconia balls in the mixture in the step S1 is (4-6): 1, the solid-liquid ratio of the mixture to absolute ethyl alcohol is (8-12): 1, and the ball milling is specifically carried out for 10min and 5min in a pause mode, and is repeated for 3 times.
4. The extraction method of Tibetan tea insoluble dietary fiber according to claim 1, wherein in the step S2, the power of plasma in a low-temperature plasma gas phase modification cavity is 60-80W, the cavity temperature is 25-30 ℃, the volume ratio of argon to oxygen in the mixed gas is (8-10): 1, and the flow rate is 10-15mL/min.
5. The extraction method of Tibetan tea insoluble dietary fibers according to claim 1, wherein the feed liquid ratio of the pretreated tea powder to water in the step S3 is 1 (8-10), and the adding amount of the alkyl glycoside-chitosan/graphene quantum dot compound is 0.2-0.4% of the mass of tea pulp.
6. The extraction method of Tibetan tea insoluble dietary fiber according to claim 5, wherein the preparation method of the alkyl glycoside-chitosan/graphene quantum dot compound is as follows: Step 1, adding 8-10mg/mL graphene quantum dot aqueous dispersion liquid into 40-50mg/mL chitosan acetic acid solution, stirring for 1.5-2h at 25-35 ℃, and regulating pH to 7.0 to obtain chitosan/graphene quantum dot suspension; And 2, adding 24-28 mg/mL alkyl glycoside ethanol solution into the chitosan/graphene quantum dot suspension, stirring for 10-14h at 30-40 ℃, centrifuging, collecting precipitate, washing, redispersing in deionized water, and freeze-drying to obtain the alkyl glycoside-chitosan/graphene quantum dot compound.
7. The method for extracting Tibetan tea insoluble dietary fiber according to claim 6, wherein the volume ratio of the chitosan acetic acid solution to the graphene quantum dot aqueous dispersion in the step 1 is (4-6): 1.
8. The extraction method of Tibetan tea insoluble dietary fiber according to claim 6, wherein the volume ratio of the chitosan/graphene quantum dot suspension to the alkyl glycoside ethanol solution in the step 2 is (4-6): 1.
9. The method for extracting Tibetan tea insoluble dietary fiber according to claim 1, wherein the alpha-amylase is added in an amount of 5-6% by mass of the pretreated tea powder, the saccharifying enzyme is added in an amount of 0.8-1.2% by mass of the pretreated tea powder, and the neutral protease is added in an amount of 7-8% by mass of the pretreated tea powder in the step S4.
10. Tibetan tea insoluble dietary fiber prepared by the extraction method according to any one of claims 1 to 9.

Description

Tibetan tea insoluble dietary fiber and extraction method thereof Technical Field The invention belongs to the technical field of dietary fibers, and particularly relates to Tibetan tea insoluble dietary fibers and an extraction method thereof. Background The dietary fiber is used as a seventh nutrient necessary for human body, has physiological effects of improving intestinal functions, regulating blood sugar and blood fat, preventing obesity and the like, and is widely used as food quality texture improving agent and functional ingredients due to good physical and chemical properties such as water holding, oil holding, emulsification and the like. Dietary fibers can be classified into Soluble Dietary Fibers (SDF) and Insoluble Dietary Fibers (IDF) according to solubility. The insoluble dietary fiber mainly comprises cellulose, hemicellulose and lignin, mainly plays roles of filling, water holding, adsorption, texture support and the like in a food system, and has important application value in low-fat meat products, baked foods and functional formula foods. Tibetan tea belongs to black tea, is mainly produced in Sichuan yaan, and is a main tea product for people in Tibetan area to drink daily. Researches show that the Tibetan tea is rich in functional components such as tea polysaccharide, polyphenol, organic acid and the like, and has health benefits such as antioxidation, blood lipid regulation, digestion assistance and the like. However, most of the prior researches focus on water-soluble active substances of Tibetan tea, and few researches on extraction methods and properties of insoluble components, particularly insoluble dietary fibers of Tibetan tea, are carried out. However, it is difficult to obtain insoluble dietary fiber of high purity using conventional dietary fiber extraction methods due to the particularities of Tibetan tea raw materials themselves. Firstly, the Tibetan tea is subjected to processes such as fermentation, pressing and the like, cellulose, hemicellulose and lignin in the cell wall are crosslinked to form a compact structure, in the conventional enzymolysis method, complex enzyme is difficult to penetrate the cell wall to enter the cell interior, only a small amount of substrate on the surface of tea powder can be acted, so that impurities such as starch, protein and the like wrapped in the cell cannot be fully enzymatically released, the subsequent separation and purification of insoluble dietary fibers are affected, the extraction efficiency is reduced, secondly, the Tibetan tea is rich in a large amount of polyphenol substances, the substances have stronger reducibility and chelating capacity, in the enzymolysis process, the polyphenol can be combined with the active center of the complex enzyme to destroy the spatial conformation of the enzyme, so that the enzyme activity is reduced or even inactivated, meanwhile, the polyphenol can be combined with an enzymolysis substrate to form an insoluble complex, the effective contact of the enzyme and the substrate is hindered, the progress of the enzymolysis reaction is further inhibited, and finally the enzymolysis time is prolonged, and the substrate conversion rate is lower. In addition, residual starch and protein caused by insufficient enzymolysis can be combined with target insoluble dietary fibers, so that the residual starch and protein are difficult to remove by conventional washing, impurities such as soluble polyphenol, pigment, micromolecular sugar and the like in Tibetan tea are easy to adsorb on the surface of the insoluble dietary fibers, and part of fat-soluble impurities are difficult to dissolve by a water-soluble enzymolysis system, so that the impurity content of a final product is higher, the purity is insufficient, and the subsequent application requirements cannot be met. Therefore, there is a need to develop a method for extracting Tibetan tea insoluble dietary fiber, which can effectively break the compact structure of Tibetan tea cell walls, relieve the inhibition effect of polyphenol on enzymes, and realize the sufficient removal of impurities such as starch, protein and the like, so as to improve the extraction efficiency and the product purity, and provide technical support for the high added value utilization of Tibetan tea resources. Disclosure of Invention Aiming at the technical problems, the invention aims to provide Tibetan tea insoluble dietary fiber and an extraction method thereof, and the method aims at solving the technical problems of compact Tibetan tea cell wall and enzyme activity inhibition by polyphenol, wherein Tibetan tea powder is subjected to cold ball milling-low-temperature plasma synergistic pretreatment to destroy a compact cell wall structure and improve hydrophilicity of the tea powder, then multienzyme sequential enzymolysis is carried out under the assistance of an alkyl glycoside-chitosan/graphene quantum dot compound, the graphene quantum dot in the compound can permeate