Longan whole fruit wine rich in polyphenols and preparation method of longan whole fruit wine

Abstract

The invention relates to the field of food, in particular to preparation and development of longan fruit wine rich in polyphenol. According to the method, beneficial polyphenol components in longan are fully excavated through fermentation of the whole longan fruit, the longan fruit wine product rich in polyphenol is prepared, and the fruit wine is dark red in color and good in taste and shows better antioxidant activity compared with traditional pulp fermented fruit wine through evaluation of activity such as antioxidant activity. The method disclosed by the invention is simple and reasonable, so that the selected fermentation method can greatly save the production cost of the fruit wine and improve the nutritional value of the fruit wine.

Description

Technical Field

[0001] The invention relates to the field of food, in particular to longan whole-fruit wine rich in polyphenols and a preparation method thereof. Background Art

[0002] At present, longan fruit has been widely recognized and favored by consumers for its "medicine and food" characteristics and tonic effects.

[0003] As a high-value fruit, the processing and utilization of longan has always been a focus of the entire industry. Among the many deep-processed longan products, the development of longan wine is considered an important development direction.

[0004] In this regard, Liang Siyu and others submitted a patent application on September 24, 2014, the name of which is "A longan fruit wine brewing process" (authorization number: CN104195004B); and Zeng Weicai and others submitted another patent application on March 17, 2022, the name of which is "A longan fruit wine and its preparation method" (application publication number: CN 114456895A).

[0005] Both methods are dedicated to preparing longan fruit wine with different flavors.

[0006] However, these methods still rely mainly on fermenting the longan pulp, or mixing the pulp and pit in a certain ratio for fermentation. Although these methods can meet market demand to a certain extent, they do not effectively solve the high cost of peeling and pitting longan.

[0007] Therefore, although the development prospects of longan fruit wine are broad, it still faces certain difficulties in the actual promotion and production process, which also makes the marketization process of longan fruit wine somewhat difficult.

[0008] The existing technology also has drawbacks: adjusting the color of the wine requires adding pigments, and alcohol-soluble food pigments must be used, which is costly.

[0009] On June 4, 2025, a search was conducted in the China Patent Publication Database using "longan and whole fruit and wine and fermentation" as abstract keywords and "allow synonym expansion" checked, but no relevant literature was found.

[0010] On June 4, 2025, an abstract search was conducted on CNKI for "longan and whole fruit and wine and fermentation". The following documents were found: "Characterization of Red Dragon Fruit Wine Fermented with a NewlyIdentified Yeast Strain Saccharomyces cerevisiae M7." 2025-03-01; Optimization of the Fermentation Process of Longan, Jujube and Ginger Wine by Response Surface Methodology Jiang Haixia; Zhao Hai 2024-12-15; "Tannin-Tolerant Saccharomyces cerevisiae Isolated from TraditionalFermented Tea Leaf (Miang) and Application in Fruit Wine Fermentation UsingLongan Juice Mixed with Seed Extract as Substrate; Somsay Phovisay;Pratthana Kodchasee;Aliyu Dantani Abdullahi;Nang NwetNoon Kham;Kridsada Unban》2024-04-26; Analysis of aroma components in different longan wines based on HS-SPME-GC-MS 2024-04-25; "The variation on structure and immunomodulatory activity ofpolysaccharide during the longan pulp fermentation" 2022-10-11; Optimization of Longan Fruit Wine Fermentation Process and Related Quality Analysis 2022-08-22; Optimization of longan wine fermentation process, research on antioxidant activity and quality analysis; "Key technologies and industrial demonstration for the design and creation of longan probiotic fermented intestinal health functional foods" 2021-12-27; Research on Brewing Technology of Longan and Red-fleshed Pitaya Composite Wine and Its Organic Acid Analysis 2021-10-18; Effect of Acetic Acid Bacteria on Acetic Acid Fermentation of Longan Fruit Wine, July 23, 2021 Research Progress on Preservation and Processing of Lingnan Specialty Fruits (November 16, 2020) Preparation of composite fruit wine of garlic extract and grape juice, December 20, 2019; "Effects of Saccharomyces cerevisiae in association with Torulaspora delbrueckii on the aroma and amino acids in longan wines." 2019-09-29; Analysis of changes in organic acids during the brewing process of longan wine, July 20, 2019; Optimization of Acetic Acid Fermentation Process and Analysis of Flavor Components of Compound Longan Fruit Vinegar, December 10, 2018; Research on Brewing Technology of Forsythia Longan Sparkling Wine, August 15, 2018 "Fermentation process optimization and chemical constituent analysis on longan (Dimocarpus longan Lour.) wine" 2018-08-01; Conghua Traditional Chinese Medicine and Natural Products Key Technology Integrated Innovation Platform, March 6, 2018; Research on Brewing Technology of Longan and Lychee Wine and Its Comprehensive Processing and Utilization, January 1, 2018; Research on Brewing Technology of Luzhou Late-ripening Longan Fruit Wine, June 20, 2017; Research on Optimization of Fermentation Conditions for Hainan Longan Fruit Wine, May 20, 2017 Comparison of Fermentation Performance of Longan Fruit Wine Fermented by Different Yeasts, September 15, 2016 Key Technologies and Industrialization of Comprehensive Processing of Bulk Fruits in South China, August 31, 2016 Optimization of Fermentation Conditions and Antioxidant Activity of Longan Fruit Wine, July 25, 2015; Research on Improving the Quality of Papaya Wine, December 28, 2014 "Fruit wine is popular, has great development potential and will lead the future wine industry" 2014-12-15; "Development of Longan and Lychee Wine Brewing Technology and Its Comprehensive Processing and Utilization" 2013-06-04; Study on the Double Yeast Mixed Fermentation of Longan-Pineapple Composite Wine, July 1, 2012; Screening of Longan Fruit Wine Brewing Yeast and Optimization of Fermentation Conditions, February 25, 2008 Key Banana Processing Technologies and Product Development, December 15, 2007 "Compound Pure Bacteria Brewing Longan Fruit Wine and Its Process Optimization" 2007-07-18; Research on Key Fermentation Technologies of Lychee and Longan Wine and Comprehensive Utilization of By-products, March 7, 2007; "New Technology for Processing Fruit Wine and Vinegar in Southern Subtropical Areas" 2007-01-01; Screening of strains and process optimization for brewing longan wine 2006-06-30 "Research and Development of Sub-Related Fruit Wine" 2006-01-01.

[0011] After careful reading, the above documents do not disclose the idea of ​​this patent.

[0012] It is completely different from the conception of this patent. Summary of the Invention

[0013] Purpose of the invention: To provide a better longan whole fruit wine rich in polyphenols and a preparation method thereof. For specific purposes, please refer to the multiple substantial technical effects in the implementation part.

[0014] In order to achieve the above purpose, the present invention adopts the following technical solutions: The polyphenol-rich longan whole fruit wine is characterized in that the whole longan fruit is crushed without peeling or removing the core and then fermented, and contains enriched polyphenol compounds.

[0015] A further technical solution of the present invention is to include the following steps: S1 Raw material processing: Screening and processing of fresh longan whole fruits. Fresh longan removes branches to obtain whole fruits, washes with clean water, and then crushes with a screw pump; S2 Saccharification: Add sulfur dioxide and sugar water according to the proportion to the sterilized and crushed longan pulp for saccharification; S3 Fermentation: Mix sugar water with longan raw materials, add pectinase, mix well, and then add yeast for fermentation; S4 Separation: After fermentation is completed, let it stand for 5 days, and then separate the original wine and pomace through the sieve plate provided in the fermentation tank; S5 After standing for 45 days, the precipitate was removed and 0.005% bentonite was added for adsorption for 15 days to obtain the original longan fruit wine.

[0016] A further technical solution of the present invention is that the disinfection treatment in step S1 is carried out by soaking in 75% ethanol for 1 hour.

[0017] A further technical solution of the present invention is that in the saccharification treatment described in step S2, the concentration of sulfur dioxide added is 0.01%, the ratio of sugar to water is 1:1, and the concentration of sugar water is: (fermentation liquid volume * 230g / L - longan raw material sugar content * longan raw material weight) / sugar water volume.

[0018] A further technical solution of the present invention is that in step S3, pectinase is added at a concentration of 0.002%, and after enzymatic hydrolysis for 1 hour, 0.02% CECA yeast is added, and the fermentation temperature is controlled at 19°C; the yeast activation process is as follows: CECA yeast is dissolved in longan juice containing 5% sugar water at 35-40°C, kept warm for 20-25 minutes, and yeast is added when the fermentation tank temperature reaches 28°C, and kept warm for 24 hours.

[0019] A further technical solution of the present invention is that the fermentation endpoint in step S4 is defined as the fermentation sugar content being lower than 20 g / L.

[0020] A further technical solution of the present invention is that in step S5, the alcohol content of the original wine is 13±0.5%vol, and the polyphenol content is ≥1000mg / L The longan fruit wine prepared by the preparation method is used in the preparation of fruit wine or health products.

[0021] Method for adjusting the color of longan whole fruit wine using longan peel and longan core.

[0022] The invention discloses a method for increasing the contents of gallic acid, catechin, vanillic acid and catechin in longan whole fruit wine by fermentation, and a method for improving the free radical scavenging and antioxidant capabilities.

[0023] The present invention adopting the above technical solution has the following beneficial effects compared with the prior art: (1) The present invention adopts the whole fermentation of longan, eliminating the longan peeling and core removal process, greatly shortening the raw material processing and processing costs, making full use of the functional active substances in the longan peel and core, and greatly exerting the "medicine and food homology" characteristics of longan.

[0024] (2) The process for preparing longan fruit wine is simple, suitable for industrial production, and conducive to promotion and application. (3) The longan fruit wine produced by the present invention is rich in polyphenols (total phenols ≥ 1000 mg / L), has a brownish-yellow color, good taste, and is rich in nutrients, making it suitable for most people. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to further illustrate the present invention, the following is further described with reference to the accompanying drawings: Figure 1 Table 1 is the sensory scoring table of longan fruit wine; Figure 2 For comparison of fermentation results; Figure 3 For the appearance comparison of fermentation results; Figure 4 and Figure 5 This is a comparison of the enrichment of key components in whole fruit fermented wine (LZ) and pulp fermented wine (LZ); Figure 6 For the comparison of the ingredients of fruit wine; Figure 7 It is a line graph of total antioxidant. DETAILED DESCRIPTION

[0026] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0027] This patent provides multiple parallel solutions. The differences in expression are improvements based on the basic solution or parallel solutions. Each solution has its own unique characteristics. In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0028] The preparation and development of a longan fruit wine rich in polyphenols comprises the following steps: Remove the branches and leaves of fresh longan, wash it, disinfect it with 75% ethanol, and then crush it.

[0029] Add sulfur dioxide and pectinase to the crushed longan jam and mix it with a certain proportion of sugar water for saccharification Add activated yeast to the saccharified longan pulp for fermentation After fermentation is complete, filter with a sieve plate to separate the lees After 45 days of precipitation, the precipitate was removed and 0.05% bentonite was added for adsorption. After 15 days, the supernatant was taken to obtain the original longan fruit wine.

[0030] Preferably, the sugar water is added in a ratio of 1:1, and the concentration of the sugar water is: (fermentation liquid volume*230g / L-longan raw material sugar content*longan raw material weight) / sugar water volume.

[0031] Preferably, the added amount of sulfur dioxide is 0.01%, and the added amount of pectinase is 0.002%.

[0032] Preferably, the saccharification time is 12-14 hours and the saccharification temperature is 28°C.

[0033] Preferably, the yeast activation method is: dissolving CECA yeast in 5% sugar water (longan juice) at 35-40° C. and keeping the temperature for 20-25 minutes.

[0034] Preferably, the yeast is added in an amount of 0.02% and is added to a fermentation tank and kept warm at 28° C. for 24 hours.

[0035] Preferably, the fermentation temperature is 19° C., and the fermentation endpoint is a sugar content lower than 20 g / L.

[0036] Preferably, the polyphenol content in the fruit wine is ≥1000 mg / L. Example

[0037] Preparation of longan whole fruit fermented wine: 300 kg of fresh and plump "Qiuxiang" variety longan with a sugar content of 13°Bx was selected. After removing the branches and leaves, 250 kg was selected and washed with clean water. The longans were soaked in 75% ethanol for 15 minutes, dried, crushed with a screw pump, and loaded into a 500L fermentation tank. 25 g of sulfur dioxide was added.

[0038] Add 5g of pectinase and 250L of sugar water with a sugar content of 33°Bx to the fermentation tank. After enzymatic hydrolysis for 2 hours, saccharify at 28°C for 12 hours, add 50g of activated yeast, mix well, and keep warm at 28°C for 24 hours.

[0039] The temperature of the fermentation tank was adjusted to 19°C, and the fermentation was terminated when the sugar content reached 2°Bx at constant temperature. The fermentation liquid was filtered through a sieve plate to obtain the fermentation liquid.

[0040] The fermented liquid was allowed to stand for 45 days, with the tank being emptied every 15 days to remove the precipitate. After 45 days, 0.05% bentonite was added and adsorbed for 15 days to obtain longan fruit wine.

[0041] Comparative Example 1 Preparation of longan pulp fermented wine: The method is consistent with that in Example 1, and the raw material is 250 kg of peeled and pitted longan pulp.

[0042] Experimental example The physical and chemical indicators and flavor characteristics of the longan fruit wine obtained in Example 1 and Comparative Example 1 were tested. The methods used were all conventional test methods, and the specific operations were as follows: Sensory evaluation of longan fruit wine (GB / T15038-2006 General analytical methods for grape wine and fruit wine) Determination of polyphenol content in longan fruit wine (T / AHFLA005-2018 Determination of total polyphenol content in plant extracts and their products - Spectrophotometric method) Determination of proanthocyanidins in longan fruit wine (DB12 / T 885-2019 Determination of proanthocyanidins in plant extracts - UV / Vis spectrophotometry) Sensory evaluation of longan fruit wine Referring to GB / T115038-2006, sensory analysis refers to the evaluator's examination of the sensory characteristics of the product through the mouth, eyes, nose and other sensory organs, that is, the inspection, analysis and evaluation of the sensory characteristics of wine and fruit wine products such as color, aroma, taste and typicality.

[0043] A panel of 10 tasters with relevant experience conducted a sensory evaluation of the appearance, aroma, taste, typical flavor characteristics and other sensory indicators of longan fruit wine. The sensory scoring standard for longan fruit wine is shown in Table 1, and the total score is 40 points.

[0044] Table 1 Sensory scoring table for longan fruit wine Table 1 Sensory evaluation standards of Iongan fruit wine The test results of the flavor characteristics, physical and chemical indicators, pesticide residue indicators, etc. of the longan fruit wine obtained in Example 1 and Comparative Example 1 are shown in Table 1.

[0045] (1) Physical and chemical indicators index Experimental group (LZ) Control group (LR) Alcohol content (%vol) 12.4 13.5 Total sugar (g / L) 54.1 46.5 Total acid (g / L) 5.7 6.6 Total esters (g / L) 0.79 0.51 Total polyphenols (mg / L) 1198 196 Proanthocyanidins (mg / L) N 118 Crude polysaccharides (mg / L) 718 1160 Note: “N” means not detected.

[0046] The results showed that the polyphenol content of the whole fruit fermentation group (LZ) was 1198 mg / L, which was much higher than the 196 mg / L of the control group (LR), successfully achieving the preparation of polyphenol-rich fruit wine.

[0047] (2) Sensory evaluation analysis The color of whole fruit fermented wine (LZ) is golden yellow, and the color of pulp fermented wine (LZ) is light yellow. The comprehensive sensory evaluation of LZ is 35 points (total score 40 points), and LR scores 26 points. LZ shows better color and taste, and better flavor.

[0048] (3) Analysis of polyphenol composition The results showed that both LZ and LR contained polyphenols, including gallic acid, epicatechin, protocatechuic acid (3,4-dihydroxybenzoic acid), vanillic acid, 4-hydroxybenzoic acid, and catechin. The gallic acid content in LZ was 980.90 mg / L, 20 times that of LR, indicating that whole-fruit fermentation significantly increased the epicatechin content in the wine. Furthermore, LZ also contained significant amounts of epicatechin (211.02 mg / L), vanillic acid (31.92 mg / L), and catechin (11.13 mg / L), indicating that whole-fruit fermentation significantly increased the contents of gallic acid, catechin, vanillic acid, and catechin in longan wine, achieving polyphenol enrichment in whole-fruit fermented longan wine.

[0049] Polyphenols LZ (mg / L) LR (mg / L) Gallic acid 980.90 44.85 Epicatechin 211.02 1.54 Vanillic acid 31.92 1.25 Salicylic acid 26.74 28.34 3,4-Dihydroxybenzoic acid 22.30 21.83 4-Hydroxybenzoic acid 11.19 11.94 Catechin 11.13 0.02 Syringic acid 9.00 1.78 Phthalic acid 6.69 5.62 Kaempferol-3-O-glucoside 4.03 0.12 Benzoic acid 3.39 4.19 Hydrocinnamic acid 2.40 0.61 (+)-Dihydroquercetin 2.27 0.29 Quercetin 1.73 0.79 Luteoloside 1.41 0.02 (+)-Dihydrokaempferol 1.17 0.19 Genistin 0.98 0.00 Note: Content ≤1mg / L is not listed (4) Antioxidant activity analysis The results showed that the DPPH scavenging rate of the LZ wine reached 87.1%, significantly higher than the 36.6% DPPH scavenging rate of the LR wine. Furthermore, in the evaluation of total antioxidant capacity, the Abs (590 nm) of the LZ wine was 0.58, significantly higher than the 0.39 of the LR wine, indicating that whole-fruit fermentation significantly enhances the antioxidant activity of wine.

[0050] The present invention generally relates to the food industry, and more particularly to the preparation and development of polyphenol-rich longan fruit wine. This method utilizes whole-fruit fermentation to fully exploit the beneficial polyphenol components in longan, producing a polyphenol-rich longan fruit wine product. The wine has a dark red color and excellent taste, and exhibits superior antioxidant activity compared to traditional pulp-fermented wines, as assessed by antioxidant activity and other evaluations. The method described herein is simple and rational, and the selected fermentation method can significantly reduce wine production costs and improve the nutritional value of the wine.

[0051] A method for fermenting whole longan fruit wine is provided. By optimizing the fermentation process, a specific whole-fruit fermentation process is established, reducing raw material processing costs, simplifying the production process, and making it suitable for industrial production. Whole-fruit fermentation improves the quality of the wine, enriching it with functional active substances such as polyphenols and proanthocyanidins, thus providing health benefits.

[0052] Moreover, this patent does not use any pigments, and can make the entire fruit have a dark red color as a result of natural fermentation without pigments, and as a fruit wine, it has excellent appearance.

[0053] Appendix 1 Microbiological indicators and pesticide residues of two fruit wines Appendix II Microbiological indicators and pesticide residues of two fruit wines The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention, and such changes and modifications are intended to fall within the scope of the claims.

Claims

1. A longan whole fruit wine rich in polyphenols, characterized in that: The method uses whole longan fruits without peeling or removing the core, and then crushes them for fermentation, which contains enriched polyphenol compounds.

2. The method for preparing the polyphenol-rich longan whole fruit wine according to claim 1, wherein: The following steps are involved: S1 Raw material processing: Screening and processing of fresh longan fruits. Fresh longan fruits are removed from branches to obtain whole fruits, washed with clean water, and crushed by a screw pump; S2 Saccharification: Add sulfur dioxide and sugar water according to the proportion to the sterilized and crushed longan pulp for saccharification; S3 Fermentation: Mix the sugar water with the longan raw materials, add pectinase and yeast, and then ferment; S4 Separation: After fermentation is completed, let it stand for 5 days, and then separate the original wine and pomace through the sieve plate provided in the fermentation tank; S5 After standing for 45 days, the precipitate was removed and 0.005% bentonite was added for adsorption for 15 days to obtain the original longan fruit wine.

3. The method for preparing the polyphenol-rich longan whole fruit wine according to claim 2, wherein: The disinfection treatment in step S1 is performed by soaking in 75% ethanol for 1 hour.

4. The method for preparing the polyphenol-rich longan whole fruit wine according to claim 2, wherein: In the saccharification treatment described in step S2, the concentration of added sulfur dioxide is 0.01%, the ratio of sugar to water is 1:1, and the concentration of sugar water is: (fermentation liquid volume * 230g / L - longan raw material sugar content * longan raw material weight) / sugar water volume.

5. The method for preparing the polyphenol-rich longan whole fruit wine according to claim 2, wherein: In step S3, pectinase is added at a concentration of 0.002%. After enzymatic hydrolysis for 1 hour, 0.02% CECA yeast is added, and the fermentation temperature is controlled at 19°C. The yeast activation process is as follows: CECA yeast is dissolved in longan juice containing 5% sugar water at 35-40°C, kept warm for 20-25 minutes, and yeast is added when the fermentation tank temperature reaches 28°C, and kept warm for 24 hours.

6. The method for preparing the polyphenol-rich longan whole fruit wine according to claim 3, wherein: The fermentation endpoint in step S4 is defined as the fermentation sugar concentration being lower than 20 g / L.

7. The method for preparing the polyphenol-rich longan whole fruit wine according to claim 3, wherein: In step S5, the alcohol content of the base liquor is 13±0.5% vol, and the polyphenol content is ≥1000 mg / L.

8. Use of the whole longan fruit wine prepared by the method for preparing longan fruit wine according to any one of claims 2 to 7 in the preparation of fruit wine or health products.

9. Method of adjusting the color of longan whole fruit wine using longan peel and longan core.

10. A method for increasing the content of gallic acid, catechin, vanillic acid and catechin polyphenols in longan whole fruit wine fermented by fermentation, and a method for improving free radical scavenging and antioxidant capabilities.

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