Longan fruit wine with high content of ester and preparation method thereof

Abstract

The present application belongs to the technical field of fruit wine, and particularly relates to a longan fruit wine with high ester content and a preparation method thereof. The preparation method comprises the following steps: S1. Longan pulp is squeezed to obtain pulp residue and longan juice; S2. The pulp residue is crushed and added with live yeast for fermentation to obtain pulp fermentation product; S3. The longan juice is taken and added with brewing yeast for fermentation to obtain juice fermentation product; S4. The pulp fermentation product and the juice fermentation product are mixed, added with pectinase, and then added with Pichia anomala for secondary fermentation after standing to obtain crude fruit wine; and S5. The crude fruit wine is subjected to filtration, clarification, aging and sterilization to obtain the longan fruit wine. The longan fruit wine prepared by the present application has longan-specific aroma, coordinated and complete wine body, and good taste; the total ester content in the fruit wine composition is high, which effectively improves the quality of the longan fruit wine.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of fruit wine, and particularly relates to a longan fruit wine with high ester content and a preparation method thereof. BACKGROUND

[0002] Longan is also called longan, which belongs to the family of Sapindaceae and is a kind of fruit for both medicine and food in China. The pulp of longan is rich in monosaccharides and disaccharides (sugar content is up to 20%), various amino acids, phospholipids, ascorbic acid, riboflavin, iron and selenium and other nutrients, and also contains active polysaccharides, polyphenols, nucleosides and other physiological active ingredients, which has the effects of nourishing heart and spleen, tonifying qi and blood, anti-inflammatory, anti-aging, regulating immunity and the like. A large amount of longan is produced in China every year, but due to the restriction of preservation conditions and deep processing capacity and other factors, a large part of longan cannot be consumed in time, and finally it is mildewed and rotted, which causes not small economic losses. With the change of people's consumption concept, low-alcohol fruit wine with rich nutritional value and unique flavor is more and more favored by consumers, and brewing high-quality fruit wine is an important way for deep processing of longan, which can also alleviate the problem of longan being wasted in a large amount to some extent.

[0003] The quality of fruit wine depends on its alcohol content, sugar and acid concentration, and the types and contents of volatile aroma substances. The aroma substances in longan fruit wine are mainly esters and alcohols, and the esters are mainly pentyl formate, ethyl acetate, isoamyl acetate and ethyl hexanoate; the alcohol substances are mainly isobutyl alcohol, n-pentanol, isoamyl alcohol and beta-phenyl ethanol and other higher alcohols.

[0004] In the existing research on longan fruit wine, most of them focus on fermenting longan with other fruits or medicinal materials to prepare compound flavor fruit wine, such as patent applications CN113528261A and CN110699213A, and most of the quality aspects also focus on the health value of fruit wine. Some scholars have compared the effects of different fermentation methods on various components in longan fruit wine, but the content of ester substances in the final fruit wine is not ideal. SUMMARY

[0005] Therefore, the purpose of the present application is to provide a longan fruit wine with high ester content and a preparation method thereof, which can further improve the taste and value of the fruit wine on the basis of maintaining the original nutritional components in the fruit wine.

[0006] The purpose of the present application is achieved by the following technical solutions:

[0007] A preparation method of longan fruit wine with high ester content, comprising the following steps:

[0008] S1. Taking fresh longan, peeling and removing the core, and then squeezing the obtained pulp to obtain pulp residue and longan juice;

[0009] S2. The pulp residue is crushed, glucose solution, live yeast and appropriate amount of yeast nutrient salt are added, mixed evenly and then fermented to obtain a pulp fermentation product;

[0010] S3. The Longan juice is taken, the acidity and sugar content are adjusted, and then wine yeast is added for fermentation to obtain a juice fermentation product;

[0011] S4. The pulp fermentation product and the juice fermentation product are mixed, pectinase is added, and then Pichia anomala is added for secondary fermentation after standing to obtain a crude Longan wine;

[0012] S5. The crude Longan wine is subjected to filtration, clarification, aging and sterilization steps to obtain the Longan wine, wherein the filtration, clarification, aging and sterilization steps are all routine operations in the art.

[0013] In some embodiments, in step S1, the water content of the pulp residue is 10-15%.

[0014] In some embodiments, in step S2, the pulp residue is crushed to a particle size of 1-2 cm.

[0015] In some embodiments, in step S2, the mass ratio of the pulp residue, glucose solution and live yeast is 100-120: 5-8: 0.02-0.03, and the yeast nutrient salt serves to provide some essential nutrients for the growth of yeast to promote the growth of yeast. A person skilled in the art can add an appropriate amount according to experience.

[0016] In some embodiments, in step S2, the glucose solution is a saturated solution.

[0017] In some embodiments, in step S2, the live yeast is activated before being added.

[0018] In some embodiments, in step S2, the fermentation temperature is 25-30℃ and the fermentation time is 5-10d.

[0019] In some embodiments, in step S3, the acidity is adjusted with tartaric acid, and the pH value of the Longan juice after adjustment is 4.5-5.

[0020] In some embodiments, in step S3, the sugar content is adjusted with glucose or sucrose, and the sugar content of the Longan juice after adjustment is 20-25°Bx.

[0021] In some embodiments, in step S3, the mass ratio of the Longan juice to wine yeast is 100-120: 0.02-0.03.

[0022] In some embodiments, in step S3, the wine yeast is activated before being added.

[0023] And / or, in step S3, the fermentation temperature is 19-23℃, and the fermentation time is 10-12d.

[0024] In certain embodiments, in step S4, the added amount of pectinase and Pichia anomala is 0.05-0.1% and 0.01-0.02% of the total weight of the pulp fermentate and the juice fermentate, respectively, and the standing time after adding the pectinase is 1-2h.

[0025] And / or, in step S4, the Pichia anomala is activated before being added.

[0026] In certain embodiments, in step S4, the fermentation temperature is 18-25℃, and the fermentation time is 7-10d.

[0027] The application also provides the longan fruit wine prepared by the above method.

[0028] It should be noted that in the prior art, the general process for brewing fruit wine is: fresh pulp → pulping → acid adjustment → enzymatic hydrolysis → sugar adjustment → inoculation → fermentation → filtration → clarification → aging. Since there is no step of separating the pulp from the juice, the fermentation substrate is a semi-solid material containing juice and insoluble substances such as cellulose in the pulp, and the subsequent fermentation is directly carried out in this semi-solid material by inoculating yeast.

[0029] The performance of yeast is also one of the important factors affecting the quality of fruit wine. Saccharomyces cerevisiae has good alcohol-producing capacity, but relatively weak aroma-producing capacity. Fruit wine fermented by purebred Saccharomyces cerevisiae usually has thin aroma and flat flavor. Aroma-producing yeast has relatively strong aroma-producing capacity and can generate a variety of aromatic substances, which positively affect the flavor of fruit wine, but also has some defects, such as weak alcohol tolerance, low fermentation power, and high acetic acid yield. Therefore, mixed fermentation of Saccharomyces cerevisiae and aroma-producing yeast, so that different strains can "make up for each other's weaknesses", is a hot spot in current fruit wine brewing research. However, existing research has confirmed that whether Saccharomyces cerevisiae or aroma-producing yeast is added first, or both are added at the same time, the microbial competition or the change of the physical and chemical properties of the substrate during the fermentation process will inhibit the level of micro-metabolism, resulting in an unsatisfactory final fermentation result.

[0030] The beneficial effects of the application are:

[0031] 1. Based on the above-mentioned problems, the application creatively separates the pulp and juice of longan and uses aroma-producing yeast and Saccharomyces cerevisiae for fermentation, respectively. The fermentation of juice is mainly for alcohol production, and the fermentation of pulp is mainly for aroma production. Separate fermentation can effectively avoid the adverse effects caused by the mutual competition between the two strains, so that alcohol production and aroma production can be fully carried out.

[0032] 2. The fruit juice ferment contains abundant ethanol, and a certain amount of organic acid originally exists in the fruit pulp ferment, after mixing the two, pectinase is added, under the action of pectinase, the fruit pulp is further hydrolyzed, which has the effect of clarification, and at the same time, a part of organic acid is produced, after adding the Pichia anomala, the esterification enzyme produced in the fermentation process is used to convert ethanol and organic acid into ester, which effectively improves the content of ester in the longan fruit wine;

[0033] 3. The longan fruit wine prepared by the method has the characteristics of clear and transparent, luster, unique longan aroma, coordinated and complete wine body, and good taste; the total ester content in the fruit wine is high, which effectively improves the quality of the longan fruit wine, and provides an effective way for the deep processing of longan. DETAILED DESCRIPTION

[0034] The technical scheme of the present application will be further described in detail in combination with examples, but the protection scope of the present application is not limited to the following description.

[0035] Example 1

[0036] A preparation method of longan fruit wine with high ester content, comprising the following steps:

[0037] S1. Fresh longan is peeled and cored, and the obtained fruit pulp is pressed by a press to obtain longan juice and fruit pulp residue with a water content of 12-14%;

[0038] S2. The fruit pulp residue is crushed to a particle size of 1-2 cm, and 100 parts of the crushed fruit pulp residue, 5 parts of saturated glucose solution, 0.02 parts of active dry yeast purchased from Angel Yeast Company and 0.02 parts of yeast nutrient salt (purchased) are taken according to weight parts, the active dry yeast is activated according to the general method in the art, and then mixed uniformly with the saturated glucose solution, the fruit pulp residue and the yeast nutrient salt, and then fermented at 28-29℃ for 7 days to obtain a fruit pulp ferment;

[0039] S3. 100 parts of the longan juice are taken according to weight parts, tartaric acid is used to adjust the pH value to about 4.5, and sucrose is used to adjust the sugar content to 24°Bx, then 0.02 parts of SY fruit wine active dry yeast purchased from Angel Yeast Company is taken, activated according to the general method in the art, and then added into the longan juice, stirred and then fermented at about 20-22℃ for 10 days to obtain a fruit juice ferment;

[0040] S4. The fruit pulp ferment and the fruit juice ferment are mixed, 0.05% of pectinase (purchased from Chengdu Wanxiang Hongrun Biological Technology) of the total weight of the fruit pulp ferment and the fruit juice ferment is added, and after standing for 2 hours, 0.02% of Pichia anomala (activated before adding) of the total weight of the fruit pulp ferment and the fruit juice ferment is added, and then fermented at about 20℃ for 7 days to obtain a crude fruit wine.

[0041] S5. The crude fruit wine is filtered, clarified, aged, and sterilized according to the general method in the art to obtain the Longan fruit wine.

[0042] Example 2

[0043] A method for preparing a Longan fruit wine with high ester content, comprising the following steps:

[0044] S1. Fresh Longan is peeled and cored, and the obtained pulp is squeezed by a squeezer to obtain pulp residue and Longan juice with a water content of 12-14%;

[0045] S2. The pulp residue is crushed to a particle size of 1-2 cm, and 120 parts of the crushed pulp residue, 8 parts of saturated glucose solution, 0.03 parts of active dry yeast of Angel Yeast Co., Ltd., and 0.02 parts of yeast nutrient salt (purchased) are taken by weight, the active dry yeast is activated according to the general method in the art, and then mixed uniformly with the saturated glucose solution, the pulp residue, and the yeast nutrient salt, and then fermented at 28-29°C for 10 days to obtain a fermented pulp;

[0046] S3. 120 parts of the Longan juice are taken by weight, tartaric acid is used to adjust the pH value to about 5, and sucrose is used to adjust the sugar content to 23°Bx, then 0.03 parts of RW fruit wine active dry yeast from Angel Yeast Co., Ltd. is taken, activated according to the general method in the art, and then added to the Longan juice, stirred, and then fermented at about 20-22°C for 12 days to obtain a fermented juice;

[0047] S4. The fermented pulp and the fermented juice are mixed, 0.08% of pectinase (purchased from Chengdu Wanxiang Hongrun Biological Technology) of the total weight of the fermented pulp and the fermented juice is added, and then placed for 1.5 hours, 0.01% of Pichia anomala (activated before adding) of the total weight of the fermented pulp and the fermented juice is added, and then fermented at about 20°C for 10 days to obtain a crude fruit wine;

[0048] S5. The crude fruit wine is filtered, clarified, aged, and sterilized according to the general method in the art to obtain the Longan fruit wine.

[0049] Example 3

[0050] A method for preparing a Longan fruit wine with high ester content, comprising the following steps:

[0051] S1. Fresh Longan is peeled and cored, and the obtained pulp is squeezed by a squeezer to obtain pulp residue and Longan juice with a water content of 12-14%;

[0052] S2. The pulp residue is crushed to a particle size of 1-2 cm. Take 120 parts of the crushed pulp residue, 6 parts of saturated glucose solution, 0.03 parts of active dry yeast purchased from Angel Yeast Company, and 0.02 parts of yeast nutrient salt (purchased) by weight. Activate the active dry yeast according to the general method in the art, then mix it evenly with the saturated glucose solution, pulp residue and yeast nutrient salt. Then ferment at 28-29°C for 5 days to obtain the pulp fermentation product.

[0053] S3. Take 120 parts of the longan juice by weight. Adjust the pH value to about 4.5 with tartaric acid and the sugar content to 23°Bx with sucrose. Then take 0.03 parts of Baijiu Wang brewing active dry yeast purchased from Angel Yeast Company, activate it according to the general method in the art, and then add it to the longan juice. After stirring, ferment at about 20-22°C for 10 days to obtain the juice fermentation product.

[0054] S4. Mix the pulp fermentation product and juice fermentation product, add 0.1% pectinase (purchased from Chengdu Wanxiang Hongrun Biological Technology) of the total weight of the pulp fermentation product and juice fermentation product, and stand for 1 h. Then add 0.02% of Pichia anomala (activated before adding) of the total weight of the pulp fermentation product and juice fermentation product, and ferment at about 20°C for 9 days to obtain the crude fruit wine.

[0055] S5. Filter, clarify, age, and sterilize the crude fruit wine according to the general method in the art to obtain the longan fruit wine.

[0056] Comparative Example 1

[0057] According to the method in the literature "Yuan Xinrui, Yu Xuechun, Yang Fang, et al. Study on the combined fermentation of aromatic yeast and Saccharomyces cerevisiae for longan fruit wine [J]. China Brewing, 2020, 39(07): 74-77.", a longan fruit wine was brewed using the optimal conditions.

[0058] Comparative Example 2

[0059] A method for preparing a longan fruit wine. Fresh longans are peeled and cored, then pulped according to the method known to those skilled in the art. Then adjust the pH value of the pulp solution to about 4.5 with tartaric acid and the sugar content of the pulp solution to 24°Bx with sucrose. Then activate 0.03% SY fruit wine active dry yeast and aromatic active dry yeast (purchased from Angel Yeast) by weight of the pulp solution, respectively. After activation, add them to the pulp solution. Ferment at 25°C for 7 days, then add 0.05% pectinase of the mass of the pulp solution. After standing for 2 h, add 0.02% Pichia anomala (activated before adding) of the mass of the pulp solution. Ferment at about 20°C for 7 days. After filtration, clarification, aging, and sterilization, the longan fruit wine is obtained.

[0060] Comparative Example 3

[0061] A preparation method of longan fruit wine, the steps are the same as those in example 1, the difference is that the active dry yeast in step S1 of example 1 is replaced by SY fruit wine active dry yeast, and the SY fruit wine active dry yeast in step S3 is replaced by active dry yeast, that is, the active dry yeast is used for fermenting fruit juice, and the wine yeast is used for fermenting fruit pulp.

[0062] Comparative example 4

[0063] A preparation method of longan fruit wine, which is different from example 1 in that the steps of adding pectinase and adding Pichia anomala fermentation in step S4 are omitted, and the fruit pulp fermentation and fruit juice fermentation are mixed uniformly, then filtered, clarified, aged, sterilized.

[0064] Comparative example 5

[0065] A preparation method of longan fruit wine, which is different from example 1 in that the steps of adding pectinase and standing in step S4 are omitted, and the fruit pulp fermentation and fruit juice fermentation are mixed uniformly and inoculated with Pichia anomala for fermentation.

[0066] According to the sensory evaluation standard of longan fruit wine prepared by Yuan Xinrui et al. (literature: Research on longan fruit wine fermented by active dry yeast and wine yeast), 10 professional personnel from Sichuan Food Fermentation Industry Research and Design Institute Co., Ltd. evaluated the longan fruit wine prepared in each of the above examples and comparative examples according to the standard, and the average value of the scores of the other 8 professional personnel was taken after removing the highest score and the lowest score, and one decimal place was reserved. Table 1 below is the sensory evaluation standard.

[0067] Table 1

[0068] Item Scoring criteria Score Color (20) Golden yellow, bright and attractive, with luster 16-20 Yellow, with some luster 11-15 Light yellow, basically without luster 6-10 Slightly yellow, without luster 0-5 Aroma (30) Pure and fragrant, rich and harmonious wine aroma, harmonious fruit aroma and wine aroma 26-30 Rich and harmonious Longan aroma and wine aroma 21-25 Longan aroma and wine aroma are relatively weak, without bad smell 16-20 Unpleasant aroma or bad smell 11-15 Insufficient aroma, with obvious bad smell 0-10 Taste (40) Full-bodied, mellow and smooth, with appropriate acidity and sweetness, long aftertaste 31-40 Full-bodied, mellow and smooth, with appropriate acidity and sweetness, long aftertaste 21-30 Light-bodied, without obvious off-flavor, with single aftertaste 11-20 Flat taste, with heavy acidity and astringency, basically without aftertaste 0-10 Typicality (10) Typical and perfect 9-10 Typical and good 7-8 Typical and general 5-6 Without Longan fruit wine style, typical and poor 0-4

[0069] The total sugar, total acid and alcohol content of the longan fruit wine were determined according to GBT 15038-2006 "General analysis method for grape wine and fruit wine", and the total ester content was determined according to the method in GBT 27588-2011 "Liquor". The determination results are shown in Table 2.

[0070] Table 2

[0071] Item Alcohol content (%vol) Total sugar (g·L-1) Total acid (g·L-1) Total ester (mg·L-1) Sensory score Example 1 18.9 2.3 5.1 331.55 85.3 Example 2 19.1 2.2 5.0 326.87 84.6 Example 3 18.5 2.4 4.8 340.66 82.1 Comparative Example 1 13.2 3.2 6.5 280.74 75.2 Comparative Example 2 20.0 2.1 7.0 285.32 77.6 Comparative Example 3 14.4 4.3 6.8 209.15 65.0 Comparative Example 4 15.3 3.7 6.2 240.71 71.3 Comparative Example 5 18.1 2.4 4.9 315.93 80.1

[0072] According to table 2, the longan fruit wine prepared by the application is better than the comparative examples in overall sensory score, the fruit wine is clear and transparent with luster, has the unique aroma of longan, the wine body is coordinated and complete, and the taste is good; the total ester content in the fruit wine is significantly higher, which effectively improves the quality of longan fruit wine and provides an effective way for deep processing of longan.

[0073] The foregoing is considered as illustrative only of the principles of the application. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the application to the exact construction and operation described. Accordingly, all such variations are intended to be included within the scope of the present application as defined in the claims below and their equivalents.

Claims

1. A method for preparing a longan fruit wine having a high content of ester substances, characterized by, The method comprises the following steps: S1. Taking fresh longan and peeling and removing the core, and then squeezing the obtained pulp to obtain pulp residue and longan juice; S2. Crushing the pulp residue, adding glucose solution, live yeast and appropriate amount of yeast nutrient salt, mixing uniformly and then fermenting to obtain pulp fermentation product; S3. Taking the longan juice, adjusting the acidity and sugar content, and then adding Saccharomyces cerevisiae for fermentation to obtain juice fermentation product; S4. Mixing the pulp fermentation product and the juice fermentation product, adding pectinase, standing, and then adding Pichia anomala for secondary fermentation to obtain crude longan fruit wine; S5. Filtering, clarifying, aging and sterilizing the crude longan fruit wine to obtain the longan fruit wine. In S4, the adding amount of the pectinase and the Pichia anomala is 0.05%-0.1% and 0.01%-0.02% of the total weight of the pulp fermentation product and the juice fermentation product respectively; and the Pichia anomala is activated before being added.

2. The method of claim 1, wherein the ester content of the wine is increased by adding a fruit extract of longan. In S1, the water content of the pulp residue is 10-15%. ​ 3. The method of claim 1, wherein the ester content of the wine is increased by adding a fruit extract of longan. In S2, the pulp residue is crushed to a particle size of 1-2 cm. ​ 4. The method for preparing a longan fruit wine with high ester content according to claim 1, characterized in that, In S2, the mass ratio of the pulp residue, glucose solution and live yeast is 100-120:5-8:0.02-0.

03. In S2, the glucose solution is a saturated solution.

5. The method for preparing a longan fruit wine with high ester content according to claim 1, characterized in that, In S2, the live yeast is activated before being added. In S2, the fermentation temperature is 25-30℃ and the fermentation time is 5-10 d.

6. The method of claim 1, wherein the ester content of the wine is increased by adding a fruit extract of longan to the wine. 5 In S3, the acidity is adjusted by tartaric acid, and the pH value of the longan juice after adjustment is 4.5-5. In S3, the sugar content is adjusted by glucose or sucrose, and the sugar content of the longan juice after adjustment is 20-25°Bx.

7. The method according to claim 1, wherein the ester content of the wine is increased by adding 0.1 to 0.5% of the fruit of the plant of the genus Vaccinium to 1 kg of the wine. In S3, the mass ratio of the longan juice and Saccharomyces cerevisiae is 100-120:0.02-0.

03. In S3, the Saccharomyces cerevisiae is activated before being added. In S3, the fermentation temperature is 19-23℃ and the fermentation time is 10-12 d.

8. The method according to claim 1, wherein the ester content of the wine is increased by adding 0.1 to 0.5% of the extract of the fruit of the plant of the genus of Garcinia. In S4, the secondary fermentation temperature is 18-25℃ and the fermentation time is 7-10 d.

9. The longan fruit wine prepared by the method according to any one of claims 1-8.