CN113004997A

CN113004997A - Persimmon leaf fermented product, preparation method and application thereof, and beverage

Info

Publication number: CN113004997A
Application number: CN202110418220.6A
Authority: CN
Inventors: 田辉; 范文广; 赵萍; 曹莹莹; 尹丹丹; 张燕龙; 王永刚; 任海伟; 李雪; 李欣荣; 甄梦佳; 王琰
Original assignee: Lanzhou University of Technology
Current assignee: Lanzhou University of Technology
Priority date: 2021-04-19
Filing date: 2021-04-19
Publication date: 2021-06-22

Abstract

The invention is suitable for the technical field of food, and provides a persimmon leaf fermented product, a preparation method, application and a beverage thereof, wherein the preparation method of the persimmon leaf fermented product comprises the following steps: placing folium kaki and sugar in water, heating and leaching to obtain folium kaki juice; inoculating lactobacillus plantarum and yeast into the persimmon leaf juice for fermentation to obtain persimmon leaf fermented product. According to the preparation method of the persimmon leaf fermented product provided by the embodiment of the invention, the persimmon leaves are subjected to synergistic fermentation by adopting the lactobacillus plantarum and the saccharomycetes, so that the extraction amount of flavonoid substances in the persimmon leaves can be increased, and the taste and flavor of the persimmon leaf fermented product can be improved; the persimmon leaf fermented product prepared by the preparation method has low alcoholic strength and high average content of flavonoids, has yeast and lactobacillus plantarum fermented flavor and persimmon leaf specific flavor, and can be used as beverage.

Description

Persimmon leaf fermented product, preparation method and application thereof, and beverage

Technical Field

The invention belongs to the technical field of food, and particularly relates to a persimmon leaf fermented product, and a preparation method, application and beverage thereof.

Background

With the improvement of the economic level and the continuous improvement of the quality of life in China, people are pursuing healthier diet or functional diet more and more. The lactic acid bacteria and the yeast are adopted to ferment the plant raw materials, and the prepared fermented product containing the specific bioactive components is gradually favored by people, such as plant enzyme, fermented fruits and vegetables and other biological products for manufacturing functional foods. Wherein the edible plant ferment is prepared from microorganism (yeast, lactobacillus, etc.) by fermentation, and contains specific bioactive components. At present, the edible plant enzyme is about 100 million t all over the world, the sale amount reaches 30 hundred million dollars, and more than 3000 plant enzyme manufacturers all over the world exist.

By artificially inoculating microorganisms, the growth advantage of beneficial strains can be quickly formed in a fermentation environment, the propagation of mixed bacteria and pathogenic bacteria is inhibited, the production safety of fermentation products is ensured, and the flavor and the generation of active substances are improved.

Lactic acid bacteria are a class of bacteria that utilize fermentable sugars to produce large amounts of lactic acid. Lactic acid bacteria can generate organic acids such as lactic acid and the like, and various natural substances for inhibiting harmful bacteria such as bacteriocin, hydrogen peroxide, diacetyl and the like through a series of complex metabolic processes, and the substances can maintain the balance of flora in the gastrointestinal tract and improve the immunity of the body.

The probiotic fermented fruit and vegetable juice has the advantages of both fruits and vegetables and probiotics, and can produce special fermented flavor and nutrient substances such as organic acid, vitamins, amino acids, various enzymes and the like on the basis of the original flavor and nutrition of fruits and vegetables, so that the flavor and functionality of fruit and vegetable products are improved. If Zhang Jing and the like utilize lactobacillus brevis to ferment the apple juice, the result shows that the quality of the fermented apple juice is obviously improved, the contents of lactic acid, fumaric acid, acetic acid and quinic acid are obviously increased, and the contents of malic acid and succinic acid are continuously reduced. 1 plant of lactobacillus plantarum with good gastrointestinal tract environment tolerance is screened from the jade and the like, the strain is found to be suitable for fermenting various fruit and vegetable juices, particularly, the fresh smell of carrot juice can be improved, and the number of the fermented viable bacteria reaches 1.24 multiplied by 10⁹CFU/mL, and the strain has the function of relaxing bowel and good fermentation characteristic, so that the strain can be used for developing probiotic functional fruit and vegetable fermented beverages. According to researches on the production of fermented pear juice by lactobacillus plantarum, the fermentation of lactobacillus produces acid, so that the activity of polyphenol oxidase is inhibited, and the preservation of phenols, ascorbic acid and other substances in the pear juice is facilitated.

The Yeast (Yeast) is a large variety, and the Yeast (Saccharomyces sp) is the most closely related to human, and the Saccharomyces cerevisiae (Saccharomyces cerevisiae) is the representative strain of Saccharomyces, and has been used for brewing and leavening for the first time. Yeast cells are rich in proteins, amino acids, nucleic acids, B vitamins, trace elements and various digestive enzymes. The cell wall contains various bioactive substances (mannose, beta-glucan, glutathione, ergosterol), can be absorbed as nutrient substances, and can promote immunoreaction and proliferation of beneficial bacteria such as Bacillus bifidus and Lactobacillus. Converting saccharide into ethanol and CO by saccharomyces cerevisiae through anaerobic fermentation₂And other flavor substances, and thus are widely used in fruit wine, beer, yellow wine and the likeIn the liquor industry.

Persimmon tree (Diospyros kaki L.) is an important commercial fruit crop and is widely cultivated in asian countries of china, japan, korea, and the like. The folium kaki is fresh leaf or dry leaf of Diospyros kaki Thunb. Persimmon leaf is a traditional Chinese medicine and was first recorded in Yunnan materia Medica of Ming Dynasty. Shuangshi leaf can be used for treating chronic ulcer. The persimmon leaves are clinically applied to the treatment of the apoplexy and the apoplexy symptoms for a long time, and the ischemic apoplexy, the angina pectoris, the internal hemorrhage, the paralysis, the frostbite, the burn, the hemorrhage and the constipation are improved. Persimmon leaf has free radical scavenging, neuroprotective, thrombosis inhibiting, atherosclerosis inhibiting, antimutagenic, antihistaminic and antiallergic properties. In addition, they are used as hypotensive drugs in japanese traditional medicine. The brain-heart-clearing tablets prepared from the persimmon leaf extract are listed in the supplement version of Chinese pharmacopoeia in 2010 and are used as traditional Chinese medicine protection varieties for preventing and treating coronary heart disease and cerebral arteriosclerosis. The curative effects of persimmon leaf on cough, internal hemorrhage, hypertension, cerebral arteriosclerosis and coronary heart disease are reported in Guangxi Chinese herbal medicine Standard (1990). The persimmon leaf tea contains abundant flavonoids and high content of vitamin C, and can partially replace expensive citrus fruits. Persimmon leaves have long been used as a raw material for health drinks, such as in china and japan, for lowering blood pressure, eliminating cholesterol accumulation and preventing melanin accumulation, and are popular with china and japanese. Persimmon leaves also have a whitening effect, and are becoming more and more popular not only in pharmaceutical applications but also in the cosmetic and food industries. In addition, it can also regulate immune function and inhibit inflammation. Persimmon leaf has various pharmacological and therapeutic effects of protecting heart, resisting oxidation, resisting inflammation, resisting atherosclerosis, resisting diabetes, stopping bleeding, etc., and may be caused by various flavonoids and terpenoids contained in persimmon leaf. Persimmon leaves have good food safety, and no side effect or toxicity report has been reported for years on the herbal medicine. The toxicity research at present shows that the persimmon leaves have no toxic effect. More and more scientific evidence indicates that persimmon leaves as health care products will develop vigorously in the future.

However, the existing products fermented by persimmon leaves have the problems of higher alcoholic strength, lower concentration of flavonoids and the like, so improvement of the persimmon leaf fermentation process is urgently needed.

Disclosure of Invention

The embodiment of the invention aims to provide a preparation method of persimmon leaf fermented product, aiming at solving the problems in the background art.

The embodiment of the invention is realized in such a way that the preparation method of the persimmon leaf fermented product comprises the following steps:

placing folium kaki and sugar in water, heating and leaching to obtain folium kaki juice;

inoculating lactobacillus plantarum and yeast into the persimmon leaf juice for fermentation to obtain persimmon leaf fermented product.

In a preferable embodiment of the present invention, the mass concentration of the persimmon leaves in the persimmon leaf juice is 2 to 3% W/V.

In another preferable embodiment of the present invention, the mass concentration of sugar in the persimmon leaf juice is 1 to 3% W/V.

As another preferred embodiment of the present invention, the sugar is sucrose. The sugar may be selected from sugars such as stevia, glucose, and fructose, but is not limited thereto.

As another preferable scheme of the embodiment of the invention, the temperature of the heating leaching is 90-100 ℃, and the time of the heating leaching is 10-30 min.

As another preferable scheme of the embodiment of the invention, the inoculation amount of the lactobacillus plantarum is 0.5-1.5% V/V of persimmon leaf juice; the inoculation amount of the yeast is 0.5-1.5% V/V of the persimmon leaf juice.

As another preferable scheme of the embodiment of the invention, the fermentation temperature is 35-39 ℃, and the fermentation time is 12-48 h.

Another object of the present invention is to provide a persimmon leaf fermented product prepared by the above preparation method.

Another object of the present invention is to provide an application of the persimmon leaf fermented product in preparing a beverage.

Another object of the present invention is to provide a beverage, which comprises a part or all of the above persimmon leaf fermented product.

The beverage may be tea, beverage, etc., and may further contain food additives such as sucrose, but is not limited thereto.

According to the preparation method of the persimmon leaf fermented product, provided by the embodiment of the invention, the persimmon leaves are subjected to synergistic fermentation by adopting the lactobacillus plantarum and the saccharomycetes, so that the extraction amount of flavonoid substances in the persimmon leaves can be increased, and the taste and flavor of the persimmon leaf fermented product can be improved; the persimmon leaf fermented product prepared by the preparation method has low alcoholic strength and high average content of flavonoids, has yeast and lactobacillus plantarum fermented flavor and persimmon leaf specific flavor, and can be used as beverage.

Drawings

FIG. 1 is a graph of rutin standard curve.

FIG. 2 is a graph of ethanol standard curve.

FIG. 3 is a graph showing the variation of the concentration of total flavonoids in persimmon leaf fermented product during fermentation.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

The embodiment provides a preparation method of persimmon leaf fermented product, which comprises the following steps:

s1, picking fresh persimmon leaves, naturally drying to obtain dried persimmon leaves, and storing in a self-sealing bag for later use.

S2, subpackaging the dried persimmon leaves into glass containers in a shape of 3cm in side length, adding sucrose, adding water to a constant volume, sealing, placing into a water bath kettle, heating and leaching at 90 ℃ for 10min, and cooling to obtain persimmon leaf juice; wherein the mass concentration of the persimmon leaves in the persimmon leaf juice is 2% W/V, and the mass concentration of the sucrose is 1% W/V.

S3, strain activation: inoculating the freeze-preserved Lactobacillus plantarum strain (isolated from traditional Chinese cabbage, commercially available product) at a ratio of 2% (V/V) into MRS broth culture medium under aseptic condition, culturing at 37 deg.C for 24 hr, and continuously activating for 2 times to obtain Lactobacillus plantarum; under aseptic conditions, active dry yeast (a commercial product) is inoculated into a Potato Dextrose Agar (PDA) culture solution at a ratio of 1% (W/V), shake-cultured for 24h at 37 ℃, and then activated for 1 time at a ratio of 2% (V/V) to obtain the yeast.

S4, inoculating 0.5% (V/V) lactobacillus plantarum and 0.5% (V/V) yeast into the cooled persimmon leaf juice, fermenting at 35 ℃ for 12h, filtering under aseptic condition to remove persimmon leaves, and collecting filtrate to obtain persimmon leaf fermented product. And adding a certain amount of sucrose into the persimmon leaf fermented product to make the final total sugar degree of the persimmon leaf fermented product be 6 DEG Bx, thus obtaining the persimmon leaf beverage.

Example 2

S2, subpackaging the dried persimmon leaves into glass containers in a shape of 5cm long, adding sucrose, adding water to a constant volume, sealing, placing into a water bath kettle, heating and leaching at 100 ℃ for 30min, and cooling to obtain persimmon leaf juice; wherein the mass concentration of the persimmon leaves in the persimmon leaf juice is 3% W/V, and the mass concentration of the sucrose is 3% W/V.

S3, strain activation: inoculating the strain of Lactobacillus plantarum to MRS broth at 2% (V/V) under aseptic condition, culturing at 37 deg.C for 24 hr, and continuously activating for 2 times to obtain Lactobacillus plantarum; inoculating active dry yeast into PDA culture solution at a ratio of 1% (W/V) under aseptic condition, shake culturing at 37 deg.C for 24h, and activating at a ratio of 2% (V/V) for 1 time to obtain yeast.

S4, inoculating 1.5% (V/V) lactobacillus plantarum and 1.5% (V/V) yeast into the cooled persimmon leaf juice, fermenting at 39 ℃ for 48 hours, filtering to remove persimmon leaves under aseptic conditions, and collecting filtrate to obtain persimmon leaf fermented product. And adding a certain amount of sucrose into the persimmon leaf fermented product to make the final total sugar degree of the persimmon leaf fermented product be 8 DEG Bx, thus obtaining the persimmon leaf beverage.

Example 3

S2, subpackaging the dried persimmon leaves into glass containers in a shape of 4cm in side length, adding sucrose, adding water to a constant volume, sealing, placing into a water bath kettle, heating and leaching at 93 ℃ for 15min, and cooling to obtain persimmon leaf juice; wherein the mass concentration of the persimmon leaves in the persimmon leaf juice is 2.3% W/V, and the mass concentration of the sucrose is 1.5% W/V.

S4, inoculating 0.8% (V/V) lactobacillus plantarum and 1.2% (V/V) yeast into the cooled persimmon leaf juice, fermenting at 36 ℃ for 24 hours, filtering to remove persimmon leaves under aseptic conditions, and collecting filtrate to obtain persimmon leaf fermented product. And adding a certain amount of sucrose into the persimmon leaf fermented product to make the final total sugar degree of the persimmon leaf fermented product be 8 DEG Bx, thus obtaining the persimmon leaf beverage.

Example 4

S2, subpackaging the dried persimmon leaves into glass containers in a shape of 4cm in side length, adding sucrose, adding water to a constant volume, sealing, placing into a water bath kettle, heating and leaching at 95 ℃ for 25min, and cooling to obtain persimmon leaf juice; wherein the mass concentration of the persimmon leaves in the persimmon leaf juice is 2.5% W/V, and the mass concentration of the sucrose is 2.5% W/V.

S4, inoculating 1.2% (V/V) lactobacillus plantarum and 0.8% (V/V) yeast into the cooled persimmon leaf juice, fermenting at 38 ℃ for 36h, filtering under aseptic conditions to remove persimmon leaves, and collecting filtrate to obtain persimmon leaf fermented product. And adding a certain amount of sucrose into the persimmon leaf fermented product to make the final total sugar degree of the persimmon leaf fermented product be 7 DEG Bx, thus obtaining the persimmon leaf beverage.

Example 5

S2, subpackaging the dried persimmon leaves into glass containers in a shape of 4cm in side length, adding sucrose, adding water to a constant volume, sealing, placing into a water bath kettle, heating and leaching at 90 ℃ for 20min, and cooling to obtain persimmon leaf juice; wherein the mass concentration of the persimmon leaves in the persimmon leaf juice is 3% W/V, and the mass concentration of the sucrose is 2% W/V.

S4, inoculating 1% (V/V) lactobacillus plantarum and 1% (V/V) yeast into the cooled persimmon leaf juice, fermenting at 37 ℃ for 12h, filtering to remove persimmon leaves under aseptic condition, and collecting filtrate to obtain persimmon leaf fermented product. And adding a certain amount of sucrose into the persimmon leaf fermented product to make the final total sugar degree of the persimmon leaf fermented product be 8 DEG Bx, thus obtaining the persimmon leaf beverage.

Experimental example:

the first experiment method comprises the following steps: the persimmon leaf fermented product with the optimal combination is obtained through orthogonal experiments, and meanwhile, a certain content of sucrose is added into the persimmon leaf fermented product, so that the optimal sucrose adding amount is determined according to sensory evaluation (see table 1).

The experimental process is as follows:

1. single factor experiments: and analyzing factors and levels thereof influencing the flavor of the persimmon leaf fermented product.

(1) Addition amount of folium kaki

Adding 1%, 2% and 3% (W/V) dry folium kaki into glass bottle, adding water to desired volume, extracting at 100 deg.C for 20min, and cooling. The extract was subjected to sensory evaluation in terms of flavor (see table 1).

(2) Leaching temperature and time

Leaching at 2% (W/V) of folium kaki at 90 deg.C for 10min, 90 deg.C for 20min, 90 deg.C for 30min, 100 deg.C for 10min, and 100 deg.C for 20 min. After cooling, the taste and smell of the leaching solution were evaluated organoleptically (see table 1), and the flavonoid content was determined.

(3) Time of fermentation

Referring to the preparation method provided in example 5, persimmon leaves were extracted at 90 ℃ for 30min at 2% (W/V) and 1% (V/V) lactobacillus plantarum and 1% (V/V) yeast were inoculated, fermented at 37 ℃ for 12h, 18h and 24h, respectively, subjected to sensory evaluation (see table 1), and pH, ethanol content and flavonoid content were measured.

TABLE 1 sensory evaluation Table

2. Orthogonal experiment: taking the addition amount of folium kaki, extraction time and fermentation time as factor indexes, and performing single factor experiment to obtain L of folium kaki fermented product₉(3⁴) And (4) performing orthogonal experiments. The factor levels are shown in Table 2.

TABLE 2 levels of factors in persimmon leaf fermentation orthogonality experiments

3. Determination of pH: measured using a pH meter.

4. Measurement of sugar degree: measured using a hand-held refractometer.

5. And (3) determination of ethanol content: the ethanol content in the persimmon leaf fermentation product is measured by collecting distillate by a distillation method and titrating by using a potassium dichromate method.

(1) Preparation of ethanol Standard Curve

Ethanol standard solution: 0.25mL of absolute ethanol is added into a 100mL volumetric flask, and water is added to the scale mark, so as to obtain a 2.0mg/mL ethanol solution. 0mL, 1 mL, 2 mL, 3 mL, 4 mL, 5mL, 6 mL and 7mL are respectively taken from the ethanol solution, transferred into a 10mL colorimetric tube, added with 2.0mL of 5% (W/V) potassium dichromate solution, added with water to scale and mixed evenly. Heating in 100 deg.C water bath for 10min, and cooling. The absorbance of each standard solution was measured at a wavelength of 600nm with reference to a blank standard (tube No. 1) and plotted as a standard curve.

(2) Determination of ethanol content in persimmon leaf fermentation product

0.25mL of the distillate of the persimmon leaf fermented product was extracted and added to a 10mL colorimetric tube, the absorbance was measured by the standard curve method, and the ethanol content was calculated from the standard curve and expressed in mg/mL or V/V.

6. And (3) measuring the flavone content: the existing flavone content determination method is adopted, and details are shown in the existing literature (Wangli, Xubohui, Huaping, development of persimmon leaf flavone health-care beverage [ J ]. beverage industry, 2014,17(10): 21-24.).

II, experimental results:

1. rutin standard curve: rutin is used as reference substance of flavonoid, and standard curve of its content and absorbance value is prepared, as shown in figure 1.

2. Ethanol standard curve: according to the experimental results, a standard curve of ethanol content versus absorbance value was plotted, as shown in fig. 2.

3. Single factor experimental results:

(1) influence of persimmon leaf addition on flavor of leaching liquor: after the heat extraction, the persimmon leaf extract (persimmon leaf juice) with different concentrations has different flavors (see table 3).

TABLE 3 sensory evaluation results of persimmon leaf juice at different persimmon leaf addition levels

Wherein 1% (W/V) of the leaching liquor has light smell and taste and high sweetness; the 3% (W/V) leaching solution has high folium kaki concentration and heavy bitter taste; the 2% (W/V) leaching solution has pure smell, special taste of folium kaki, and moderate bitter taste. Therefore, the sensory acceptability of persimmon leaf juice was highest with an added amount of 2% (W/V) persimmon leaves.

(2) Influence of heating conditions on flavor of persimmon leaf juice and extraction amount of flavonoids: after determining the optimum amount of added persimmon leaves, the effect of different leaching temperatures and times on persimmon leaf juice was studied (see table 4).

TABLE 4 sensory evaluation results of persimmon leaf juice and flavonoid concentration under different extraction conditions

The increase of the leaching strength enhances the bitter taste of the persimmon leaf juice, the smell of the persimmon leaves is heavier, and the acceptance is reduced. Wherein the sensory evaluation score is highest when the extract is extracted at 90 ℃ for 20 min. The extraction amount of the flavonoid substances in the persimmon leaves can be improved by prolonging the extraction time or increasing the temperature, but the result difference is not obvious. Therefore, the optimum leaching conditions were determined to be 90 ℃ for 20min based on the sensory evaluation results.

(3) The influence of the fermentation time on the flavor of the persimmon leaf fermented product and the concentration of flavonoids substances is as follows: on the premise of the determined optimal addition amount of persimmon leaves and leaching conditions, the influence of fermentation time on persimmon leaf fermentation products was analyzed, and the results are shown in table 5.

TABLE 5 sensory evaluation results of persimmon leaf fermented products at different fermentation times

As can be seen from Table 5, the pH of the persimmon leaf fermented product gradually decreased and the ethanol content increased as the fermentation time increased, and the sensory evaluation score was the highest at 18 hours. The acidity and the ethanol content increase influence the flavor of the persimmon leaf fermented product.

In addition, after 2% (W/V) persimmon leaves are leached at 90 ℃ for 20min, the persimmon leaves are not filtered, 95% (V/V) medical alcohol is added into persimmon leaf juice to enable the ethanol content to be 0.5% (V/V) (the content is the standard of alcoholic beverages), the persimmon leaf juice is used as an alcohol control group, persimmon leaf leavening inoculated with lactobacillus plantarum and saccharomycetes is used as an inoculation experimental group, fermentation is carried out for 24h, and the concentration change of flavonoids is measured (see figure 3).

As shown in FIG. 3, the concentration of flavonoids in the alcohol control group also showed a trend of rising first and then falling, but the change range was small, with the highest concentration of flavonoids (0.082mg/mL) at 12 h. In the persimmon leaf fermented product inoculated with the microorganisms, the concentration of flavonoids is greatly increased at the early stage and gradually reduced at the later stage, and reaches the highest concentration of 0.131mg/mL which is 1.6 times of the highest concentration in an alcohol control group within 18 hours, and the content of flavonoids in dried persimmon leaves in unit weight is 6.55 mg/g. Therefore, the leaching amount of flavonoid substances in the persimmon leaves is greatly improved due to the fermentation effect of the lactobacillus plantarum and the yeast. According to the sensory evaluation score and the content of flavonoid substances, the optimal fermentation time is 18 h.

4. Orthogonal experiment results: as shown in table 6.

TABLE 6 results of orthogonal experiments

As shown in Table 6, each was analyzed based on the range differenceThe influence of the factors on the sensory evaluation score of the persimmon leaf fermented product is respectively as follows: added amount of folium kaki (A)>Extraction time (B)>Fermentation time (C), and the optimum process combination is A₁B₂C₃. However, 9 groups of orthogonal experimental results show that the optimal sensory evaluation combination of the persimmon leaf leavening is A₁B₃C₃. Experimental verification is therefore required. The sugar content, pH, alcohol content and flavonoid content of the persimmon leaf fermented products of the 3 combinations (experiment nos. 2, 3 and 8) having the highest sensory evaluation scores were measured (see table 7).

TABLE 7 results of measuring physical and chemical properties of preferred combinations

The results show that the physicochemical properties of different combinations have certain difference, wherein the concentration of the flavonoid is combined as No. 8 (A)₃B₂C₁) The highest was due to the high amount of persimmon leaves added and the highest sensory evaluation score of combination No. 3 (A)₁B₃C₃) The low concentration of the flavonoids may be caused by partial decomposition of the flavonoids due to too long fermentation time (24 h).

Sugar content, pH value and alcohol content can affect the taste and smell of persimmon leaf fermented product. Because the addition amount of sucrose in the initial persimmon leaf extract juice is 2% (W/V), the sucrose in the persimmon leaf fermented product is partially decomposed and utilized through the microbial metabolism process, the sugar degree is lower, and the correct judgment of sensory evaluation is not facilitated, so that the sucrose needs to be supplemented into the persimmon leaf fermented product, the sugar-acid ratio needs to be adjusted, and the beverage formula needs to be optimized.

5. Formula optimization of fermented persimmon leaf beverage

Based on the results of the orthogonal experiments, the 3 combinations (experiment numbers 2, 3 and 8) with the highest score and 1 presumed optimal combination A were selected₁B₂C₃Verification experiments were performed (see table 8). And adding a certain amount of sucrose into the persimmon leaf fermented product to optimize the formula of the beverage, and performing sensory evaluation to determine the optimal combination.

TABLE 8 sensory evaluation results of the preferred combinations after addition of sugar

Note: predicting optimal combinations A for orthogonal experiments₁B₂C₃。

As is clear from Table 8, sensory evaluation scores of persimmon leaf fermented products after addition of sugar were shown to be combination No. 8 (A)₃B₂C₁) Highest, and the highest flavonoid content of the combination, therefore, a was finally determined₃B₂C₁Is an optimal process combination for fermenting the persimmon leaf beverage.

In conclusion, according to the preparation method of the persimmon leaf fermented product provided by the embodiment of the invention, the persimmon leaf is subjected to synergistic fermentation by adopting lactobacillus plantarum and saccharomycetes, so that the extraction amount of flavonoid substances in the persimmon leaf can be increased, and the taste and flavor of the persimmon leaf fermented product can be improved; the persimmon leaf fermented product prepared by the preparation method has low alcoholic strength and high average content of flavonoids, has yeast and lactobacillus plantarum fermented flavor and persimmon leaf specific flavor, and can be used as beverage. Wherein when the fermentation temperature is 37 ℃, the initial sucrose content is 2% (W/V), and the inoculation ratio of the yeast and the lactobacillus plantarum is 1:1(V/V), the best process of the persimmon leaf fermented product is as follows: the addition amount of folium kaki is 3% (W/V), extraction time is 20min, and fermentation time is 12h, and the total sugar amount is 8% (W/V) after adding sucrose twice. The alcoholic strength of the fermented persimmon leaf beverage is 0.89% (V/V), the average content of flavonoids is 0.19(mg/mL), and the fermented persimmon leaf beverage has yeast and lactobacillus plantarum fermentation flavor and persimmon leaf specific flavor.

Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

Claims

1. A preparation method of persimmon leaf fermented product is characterized by comprising the following steps:

2. The method for preparing the persimmon leaf fermented product according to claim 1, wherein the mass concentration of persimmon leaves in the persimmon leaf juice is 2-3% W/V.

3. The method for preparing the persimmon leaf fermented product according to claim 1, wherein the mass concentration of sugar in the persimmon leaf juice is 1-3% W/V.

4. The method of producing a persimmon leaf fermented product according to claim 1 or 3, wherein the sugar is sucrose.

5. The method for preparing the persimmon leaf fermented product according to claim 1, wherein the temperature of the heating and leaching is 90 to 100 ℃, and the time of the heating and leaching is 10 to 30 min.

6. The method for preparing the persimmon leaf fermented product according to claim 1, wherein the inoculation amount of lactobacillus plantarum is 0.5-1.5% V/V of persimmon leaf juice; the inoculation amount of the yeast is 0.5-1.5% V/V of the persimmon leaf juice.

7. The method for preparing the persimmon leaf fermented product according to claim 1, wherein the fermentation temperature is 35-39 ℃ and the fermentation time is 12-48 hours.

8. A fermented persimmon leaf obtained by the production method according to any one of claims 1 to 7.

9. Use of the persimmon leaf fermented product of claim 8 in the preparation of a beverage.

10. A beverage comprising the fermented persimmon leaf according to claim 8 partially or entirely.