CN114391591B

CN114391591B - Tea extract, preparation method thereof and tea product

Info

Publication number: CN114391591B
Application number: CN202210103259.3A
Authority: CN
Inventors: 杨晓丽; 李国华; 胡国伟; 朱小聪; 陈家伯
Original assignee: Shanghai Kangshi Food Technology Co ltd
Current assignee: Shanghai Kangshi Food Technology Co ltd
Priority date: 2022-01-27
Filing date: 2022-01-27
Publication date: 2024-05-28
Anticipated expiration: 2042-01-27
Also published as: CN114391591A

Abstract

The specific embodiment of the invention provides a tea extract, a preparation method thereof and a tea product, wherein the preparation method of the extract is characterized in that tea is extracted by two steps, an alkaline aqueous solution is used for extraction, and then an acidic aqueous solution is used for extraction.

Description

Tea extract, preparation method thereof and tea product

Technical Field

The invention belongs to the technical field of beverage processing, and particularly relates to tea extract, a preparation method thereof and a tea product.

Background

Tea is a traditional national drink in China and has wide consumer groups. The tea cup needs to be drunk, so that not only is the tea cup and the water needed, but also proper brewing methods are needed: reasonable tea quantity, water temperature and brewing time. In particular to the industrial production of beverages, namely high-quality extraction water, tea water ratio of tea extraction, extraction temperature and extraction time.

The industrial production of tea beverage is usually started from the extraction of tea raw materials, and the process flows of centrifugation, filtration, blending, sterilization, canning and the like are carried out. The extraction is one of key links in the tea beverage production process, is also a process which is vital to influence the tea beverage quality, and the quality of the leaching effect directly influences the utilization rate of tea raw materials and the subsequent production process, so that the efficient and high-quality extraction process has great significance on the tea beverage quality. The traditional production process of the tea beverage generally adopts a one-time, high-temperature and long-time extraction process, in the existing extraction process, the aroma of the tea is seriously damaged along with the rising of the temperature and the prolonging of the time, and some tea beverages also generate unpleasant 'cooked soup flavor', lose the original aroma and the thick taste of the tea, have heavy bitter taste and weak sweet return.

Disclosure of Invention

Aiming at the problems of the prior tea beverage adopting the one-time, high-temperature and long-time extraction process, the specific embodiment of the invention provides a tea extract, a preparation method thereof and a tea product.

A method for preparing tea extract, comprising the following steps:

1) Extracting tea leaves with alkaline water, and carrying out solid-liquid separation after extraction to obtain tea leaves A and extract A;

2) Extracting the tea A with acidic water, and performing solid-liquid separation after extraction to obtain an extract B;

3) Combining the extract A and the extract B to obtain the tea extract.

Optionally, the tea is oolong tea

Optionally, the extraction temperature in the step 1) is 70-100 ℃ and the extraction time is 1-30 minutes.

Optionally, the extraction temperature in the step 1) is 85-95 ℃ and the extraction time is 3-10 minutes.

Optionally, the extraction temperature in the step 2) is 40-70 ℃ and the extraction time is 1-30 minutes.

Optionally, the extraction temperature in the step 2) is 50-60 ℃ and the extraction time is 3-10 minutes.

Optionally, the alkaline water is formulated with a weak acid and strong base salt.

Optionally, the weak acid strong alkali salt is one or more of sodium carbonate, sodium bicarbonate, potassium carbonate or potassium bicarbonate.

Optionally, the addition amount of the weak acid strong alkali salt is 0.5-5 g per 1Kg of water.

Alternatively, the acidic water is formulated with an organic acid.

Optionally, the organic acid is one or more of ascorbic acid, citric acid, malic acid or tartaric acid.

Optionally, the organic acid is added in an amount of 0.1 to 2g per 1Kg of water.

Optionally, the tea is Pu' er tea, black tea, high-baking green tea or chrysanthemum tea.

A tea extract prepared by any of the above preparation methods.

A tea product prepared from the tea extract described above.

Optionally, the tea product is instant tea powder, tea concentrate or tea beverage. The preparation method of the tea extract comprises the steps of extracting tea leaves in two steps, extracting the tea leaves by using an alkaline aqueous solution, and extracting the tea leaves by using an acidic aqueous solution.

Detailed Description

The specific embodiment of the invention provides a preparation method of tea extract, which comprises the following steps:

3) Combining the extract A and the extract B to obtain the tea extract.

According to the preparation method of the tea extract liquid, firstly, tea leaves are extracted by alkaline water, firstly, as the main components of the cell walls of the tea leaves are cellulose, hemicellulose, pectin and the like, and the environment of plant cells of the tea leaves is acidic, under the alkaline condition, partial glycosidic bond breakage of cellulose and pectin molecular degradation can be promoted, so that leaching of the effective components of the tea leaves can be promoted, the extraction yield of the tea leaves can be improved, the utilization rate of the tea leaves can be improved, the production cost can be reduced, secondly, under the alkaline condition, the polysaccharide substance produced by extraction has certain viscosity although the polysaccharide substance does not have sweet taste, saliva contains salivary amylase in the saliva, the starch can be catalyzed to hydrolyze into maltose, the maltose has sweet taste, and the polysaccharide is decomposed by enzymes for a certain time, so that the reaction time difference causes a 'sweet return' feeling, meanwhile, part of polysaccharide can be used as a substrate for extraction in acidic water, then polyphenols in the polysaccharide can be oxidized under alkaline conditions, so that the bitter taste of tea soup can be controlled at a proper level, the sweet taste is enhanced, finally, most of protein in tea is insoluble in water and can be dissolved in water to form water-soluble protein only accounting for 1-2 wt%, the content of alkali-soluble protein is more than 80wt%, the alkali-soluble protein contains hydrophobic functional groups and disulfide bonds, the alkaline solution has a destructive effect on secondary bonds of the tea protein, especially hydrogen bonds, the solubility of the protein is increased, and the dissolution rate of the protein is improved, so that under alkaline conditions, the dissolution of non-water-soluble protein in tea can be promoted, the taste and concentration of tea soup are promoted, and the effects of acidic amino acids such as aspartic acid and glutamic acid can be promoted, theanine and the like are rapidly dissolved out, and the delicate flavor of the tea soup is obviously enhanced. According to the preparation method of the tea extract, as the hemiacetal bond between the polysaccharides has small space and is folded, common reagents are difficult to enter and only hydrogen ions can enter and exit freely, so that the polysaccharides can only be hydrolyzed in an acidic solution, and the tea A is extracted by acidic water, so that the decomposition of the polysaccharides can be promoted, a certain amount of oligosaccharides, disaccharides and monosaccharides are generated, and the sweet feeling of tea soup can be increased.

In order to achieve both the extraction efficiency and flavor of tea leaves, in some embodiments, the temperature of the tea leaves is different from the temperature of the tea leaves extracted with acidic water, and the extraction is performed at a relatively higher temperature when the tea leaves are extracted with alkaline water, so that the extraction yield is advantageously improved, while the extraction is performed at a relatively lower temperature when the tea leaves A are extracted with acidic water, so that the influence of the excessive temperature on the flavor is prevented, and specific extraction temperature settings can be set according to the characteristics of different tea leaves, for example, in some embodiments, the tea leaves are oolong tea leaves, the extraction temperature of the oolong tea leaves is 70-100 ℃, the extraction temperature of the oolong tea leaves is further 85-95 ℃, and the extraction temperature of the oolong tea leaves is 40-70 ℃, and the extraction temperature of the oolong tea leaves is further 50-60 ℃.

In the preparation method of the tea extract according to the specific embodiment of the invention, considering that the extraction time is too long, although the extraction of the taste substances is sufficient, a great amount of bitter components such as ester catechin such as EGCG are extracted along with the extraction time, the aroma of tea is more lost along with the extension of the extraction time, and the concentration of tea pigment is increased along with the increase of the extraction time, so that the color of tea soup is too deep.

In some embodiments, the method for preparing the tea extract according to the embodiments of the present invention is generally obtained by adding an alkaline substance, which may be an inorganic base, an organic base, a strong base, or a weak base, to obtain the alkaline water, and in some embodiments, the alkaline water is prepared with a weak acid strong base salt, which is one or more of sodium carbonate, sodium bicarbonate, potassium carbonate, or potassium bicarbonate, and the addition amount of the weak acid strong base salt is 0.5 to 5g per 1Kg of water, and further 1 to 1.5g per 1Kg of water, for effective extraction without affecting the flavor of tea.

In some embodiments, the acidic water is generally obtained by adding an acidic substance, which may be an inorganic acid, an organic acid, a strong acid, or a weak acid, and in some embodiments, the acidic water is formulated with an organic acid, which is one or more of ascorbic acid, citric acid, malic acid, or tartaric acid, and the organic acid is added in an amount of 0.1 to 2g per 1Kg of water, and further 0.2 to 1g per 1Kg of water, for efficient extraction without affecting the flavor of the tea. The tea pigment in tea soup is usually weak ionized acid, under alkaline condition, ionization degree of tea pigment is enhanced, color is darkened, when organic acid such as citric acid, tartaric acid and malic acid is added, hydrogen ions are increased, ionization of tea pigment is restrained, so that the color is lighten, in particular, ferrous iron contained in tea is easily oxidized into ferric iron in alkaline water extraction process, and reacts with tannic acid in tea to generate dark iron tannate, and organic acid such as ascorbic acid, citric acid, tartaric acid or malic acid has reducibility, so that the ferrous iron can be reduced into ferrous iron, thereby lightening the color of tea water.

In some embodiments, the tea is oolong tea, such as North Min oolong tea or Guangdong oolong tea or strong-flavor Tieguanyin tea. The leaf of the oolong tea has slow dissolution rate of the contained substances due to the characteristic of hypertrophy, and the leaf is firstly extracted by alkaline water, so that the leaching of the effective components of the tea can be promoted, the extraction yield of the oolong tea is obviously improved, the utilization rate of the tea is further improved, and the production cost is reduced.

In some embodiments, the tea leaves are Pu' er tea, black tea, high-baking green tea and other tea leaves with high fermentation degree and high baking degree, and in some embodiments, the tea leaves are chrysanthemum tea and other tea leaves containing phenols.

In some embodiments, the tea is a finished tea, such as a tea processed by withering, green making, green removing, rolling (kneading), drying, or a deep-fermented, deep-baked tea.

In some embodiments, the weight ratio of tea to water is 1:8-1:50, further 1:25-1:35, and the weight ratio of tea A to water is 1:8-1:50, further 1:25-1:35 when the extraction is performed with alkaline water.

The specific embodiment of the invention also provides a tea extract, which is prepared by the preparation method of the tea extract.

The specific embodiment of the invention also provides a tea product which is prepared from the tea extract.

In some embodiments, the tea product of embodiments of the present invention is an instant tea powder, tea concentrate or tea beverage. For example, in some embodiments, the instant tea powder is prepared from the tea extract by filtration, sterilization, and spray drying, in some embodiments, the tea concentrate is prepared from the tea extract by filtration, concentration, and sterilization, and in some embodiments, the tea beverage is prepared from the tea extract by filtration, blending, and sterilization canning.

The tea product of embodiments of the present invention may be filtered using a variety of existing tea extract filtration modes, for example, in some embodiments, the filtration employs a combination of disc centrifugation and cartridge filtration.

In some embodiments, the tea product of embodiments of the present invention is formulated by adding water to the filtered tea extract, or by adding water and a food additive, such as a sweetener (e.g., sugar), an antioxidant, an acidity regulator, vitamin C, flavoring, and the like.

The tea product of embodiments of the present invention may be sterilized in any of a variety of conventional sterilization methods, for example, in some embodiments, microwave sterilization, UHT sterilization, or the like may be used for the sterilization process.

The invention is further illustrated by the following examples.

Examples

Description of evaluation method

Sensory evaluation: the extract was diluted with deionized water to brix=0.25%, pH adjusted to 6.3±0.2, and sensory evaluation was performed by 10 well trained sensory panelists. Sensory analysis included 7 indices of tea aroma, tea taste, bitter taste, astringency, aftertaste, sweet aftertaste, and smooth feel. The references are as follows: very good 10 minutes; 8 minutes; slightly better 6 minutes; slightly worse by 4 minutes; a difference of 2 minutes; very poor 0 minutes.

Example 1

Adding 3000g of deionized water into 4g of sodium bicarbonate for dissolution, heating to 90 ℃, adding 100g of Dahongpao tea, extracting for 4 minutes, carrying out solid-liquid separation, and cooling to obtain an extract A of Dahongpao tea and an extract A of Dahongpao tea for later use.

Adding 1g of citric acid into 3000g of deionized water for dissolution, heating to 50 ℃, adding the Dahongpao tea A, extracting for 4 minutes, carrying out solid-liquid separation, and cooling to obtain the Dahongpao tea extract B.

The above Dahongpao tea extract A and Dahongpao tea extract B were mixed to obtain Dahongpao tea extract, and the sensory evaluation results were shown in Table 1 below.

Example 2

Adding 3000g of deionized water into 2g of ascorbic acid for dissolution, heating to 50 ℃, adding the Dahongpao tea A, extracting for 4 minutes, carrying out solid-liquid separation, and cooling to obtain the Dahongpao tea extract B.

Example 3

Adding 3.5g of sodium bicarbonate into 3000g of deionized water for dissolution, heating to 90 ℃, adding 100g of Dahongpao tea, extracting for 4 minutes, carrying out solid-liquid separation, and cooling to obtain an extract A of Dahongpao tea and an extract A of Dahongpao tea for later use.

Example 4

300G of Dahongpao tea extract in examples 1-3 is respectively taken, 700g of deionized water is added, a certain amount of vitamin C is added according to actual conditions to adjust the pH of tea soup to 6.3+/-0.2, and the mixture is uniformly mixed to obtain 1kg of Dahongpao tea blending liquid.

Comparative example 1

Adding 1g of citric acid into 3000g of deionized water for dissolution, heating to 50 ℃, adding 100g of Dahongpao tea, extracting for 4 minutes, carrying out solid-liquid separation, and cooling to obtain an extract A of Dahongpao tea and an extract A of Dahongpao tea for later use.

Adding 3000g of deionized water into 4g of sodium bicarbonate for dissolution, heating to 90 ℃, adding the Dahongpao tea A, extracting for 4 minutes, carrying out solid-liquid separation, and cooling to obtain the Dahongpao tea extract B.

Comparative example 2

Adding 3000g of deionized water into 1g of sodium bicarbonate for dissolution, heating to 90 ℃, adding the Dahongpao tea A, extracting for 4 minutes, carrying out solid-liquid separation, and cooling to obtain the Dahongpao tea extract B.

Comparative example 3

Adding 3000g of deionized water into 2g of ascorbic acid for dissolution, heating to 50 ℃, adding 100g of Dahongpao tea, extracting for 4 minutes, carrying out solid-liquid separation, and cooling to obtain Dahongpao tea extract A and Dahongpao tea A for later use.

Table 1 examples 1-3, comparative examples 1-3 sensory evaluation results

According to the sensory evaluation results of table 1 above, in the sensory evaluation of examples 1 to 3, each index was significantly better than that of comparative examples 1 to 3, indicating that the flavor of the tea extract obtained by the method of extracting with an aqueous alkaline solution first and then with an aqueous acidic solution was significantly better than that obtained by the method of extracting with an aqueous acidic solution first and then with an aqueous alkaline solution, or with an aqueous alkaline solution only or with an aqueous acidic solution only.

Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention, and the scope of the invention should be assessed accordingly to that of the appended claims.

Claims

1. A method for preparing tea extract, comprising the steps of:

1) Extracting tea leaves with alkaline water at 85-95 ℃ for 3-10 min, and performing solid-liquid separation to obtain tea leaves A and extract A after extraction;

2) Extracting the tea A with acidic water at 50-60 ℃ for 3-10 min, and performing solid-liquid separation to obtain an extract B;

3) Combining the extract A and the extract B to obtain the tea extract.

2. The method of preparation according to claim 1, wherein the tea is oolong tea.

3. The method of claim 1, wherein the alkaline water is formulated with a weak acid and strong base salt.

4. A method of preparation according to claim 3 wherein the weak acid strong base salt is one or more of sodium carbonate, sodium bicarbonate, potassium carbonate or potassium bicarbonate.

5. The method according to claim 4, wherein the weak acid strong alkali salt is added in an amount of 0.5 to 5g per 1Kg of water.

6. The method of claim 1, wherein the acidic water is formulated with an organic acid.

7. The method of claim 6, wherein the organic acid is one or more of ascorbic acid, citric acid, malic acid, or tartaric acid.

8. The method according to claim 7, wherein the organic acid is added in an amount of 0.1 to 2g per 1Kg of water.

9. The method of claim 1, wherein the tea is Pu' er tea, black tea, high-fired green tea or chrysanthemum tea.

10. A tea extract, characterized in that it is prepared by the preparation method of any one of claims 1 to 9.

11. A tea product prepared from the tea extract of claim 10.

12. The tea product of claim 11, wherein the tea product is an instant tea powder, a tea concentrate or a tea beverage.