Litchi-flavored beverage containing pulp and its preparation process

Abstract

The present application belongs to the technical field of pulp fermented beverage, and particularly relates to a litchi-flavored beverage containing pulp and a preparation process thereof. The preparation process comprises the following steps: selecting fresh mature litchi, washing, shelling and removing the core to obtain litchi pulp; crushing and beating part of the litchi pulp to obtain litchi liquefied slurry; sterilizing the litchi liquefied slurry and cooling it to a low-temperature fermentation temperature, inoculating with a composite yeast, and performing low-temperature composite fermentation to obtain litchi fermentation liquor; placing the intact litchi pulp in the obtained litchi fermentation liquor, and performing vacuum-normal pressure circulation penetration treatment to make the litchi fermentation liquor enter the inside of the pulp tissue to obtain flavor-enhanced litchi pulp; mixing and blending the litchi fermentation liquor, the flavor-enhanced litchi pulp, a sugar source, an acidity regulator, a stabilizer, a color protection agent and water, and performing filling, sterilization and cooling to obtain the litchi-flavored beverage containing pulp. The obtained beverage has litchi characteristic fruit aroma, soft fermentation aroma, internal fermentation flavor of the pulp and real pulp chewing sensation.

Description

Technical Field

[0001] This invention belongs to the field of fruit pulp fermented beverage technology, specifically relating to a lychee-flavored beverage containing fruit pulp and its preparation process. Background Technology

[0002] Lychee is a specialty fruit of southern my country, with its juicy, translucent flesh and sweet aroma, possessing high nutritional and processing value. Lychee pulp contains sugars, organic acids, vitamins, and various volatile aromatic compounds, among which terpenes such as linalool, geraniol, and nerol play a significant role in the typical fruit and floral aromas of lychee. However, lychee undergoes vigorous respiration after harvest, making the pulp prone to browning, softening, and flavor deterioration, resulting in a short shelf life for fresh fruit. Therefore, processing lychee into juice beverages, pulp beverages, or fermented drinks is an important way to improve the utilization rate of lychee resources and increase the added value of products.

[0003] Existing lychee beverages are mostly made by blending lychee juice, sugar sources, acidulants, stabilizers, and flavorings. While the process is simple, the flavor relies heavily on external additives, resulting in insufficient natural lychee aroma and a relatively simple taste profile. To address these issues, researchers have discovered that fermentation technology can improve the aroma composition and mouthfeel of fruit juice beverages, significantly enhancing their flavor. During fermentation, yeast produces flavor compounds such as alcohols, esters, and organic acids, contributing to a more natural and mellow fermented aroma. Current lychee fermented beverages or lychee wines typically use lychee juice or lychee pulp as the liquid-phase fermentation substrate, employing microorganisms such as lactic acid bacteria and acetic acid bacteria for fermentation. Their main technological effect focuses on improving the sweet and sour taste, alcoholic aroma, or fermented aroma of the liquid-phase beverage. However, the fermentation process involves many details, and changes in parameters often lead to alterations in the composition of the fermentation liquid, affecting the flavor of the juice.

[0004] Furthermore, conventional fruit juice drinks only offer a pure drinking experience with a rather monotonous taste, failing to satisfy consumers' need for chewing. Based on this pain point, researchers have developed fruit juice drinks with added fruit pulp particles, adding a rich chewy texture to the sweet juice and making the drinking experience more layered. However, these chewable fruit juice drinks on the market generally suffer from a significant problem: the fruit pulp is usually simply added to the beverage system as solid particles. The flavor of the pulp itself is weak, resulting in a strong flavor in the liquid phase and a weak flavor from the pulp. While this improves the chewiness of the fruit juice, the problem of insufficient flavor harmony between the liquid and solid phases remains unresolved.

[0005] Existing technologies have not yet focused on the synergistic flavor development between fermentation liquid and whole fruit pulp, nor have they effectively solved the problem of insufficient flavor within whole lychee pulp.

[0006] Based on the above problems, it is necessary to develop a new preparation process for lychee-flavored beverages containing fruit pulp to solve the industry pain point that existing preparation processes cannot balance the deliciousness of the juice and the palatability of the fruit pulp. Summary of the Invention

[0007] To overcome the shortcomings of the existing technology, a lychee-flavored beverage containing fruit pulp and its preparation process are provided.

[0008] To achieve the above objectives, the present invention provides the following technical solution: A preparation process for a lychee-flavored beverage containing fruit pulp includes the following steps: S1. Select fresh, ripe lychees, wash, peel, and remove the pits to obtain lychee pulp; S2. Crush and pulp some of the lychee pulp, add compound liquefaction enzyme for enzymatic hydrolysis and liquefaction, and obtain lychee liquefaction pulp. S3. The litchi liquefied pulp is sterilized and then cooled to a low-temperature fermentation temperature to obtain litchi fermentation base material. S4. Inoculate the lychee fermentation substrate with compound yeast and obtain lychee fermentation liquid through low-temperature fermentation. The compound yeast is composed of sake yeast and Max Kluyveromyces. S5. Crush the remaining lychee pulp into pulp particles and soak them in the lychee fermentation liquid obtained in step S4. The soaking process adopts vacuum-atmospheric pressure osmosis treatment to allow the lychee fermentation liquid to enter the pulp tissue and obtain flavor-enhanced lychee pulp. S6. Mix and adjust the lychee fermentation liquid, flavor-enhancing lychee pulp, sugar source, acidity regulator, stabilizer, color protectant and water to obtain the blended liquid; S7. The prepared liquid is filled and sterilized, and after cooling, a lychee-flavored beverage containing fruit pulp is obtained.

[0009] The compound liquefying enzyme in step S2 is formed by combining pectinase, cellulase, hemicellulase and β-glucosidase in the following mass ratio: pectinase: cellulase: hemicellulase: β-glucosidase = 1: (0.4-0.6): (0.4-0.6): (0.1-0.2).

[0010] In step S2, the amount of compound liquefying enzyme added is 0.06%-0.18% of the mass of litchi pulp, the enzymatic hydrolysis temperature is 40-50 ℃, and the enzymatic hydrolysis time is 50-65 min.

[0011] Preferably, in step S2, the amount of compound liquefying enzyme added is 0.1%-0.15% of the mass of litchi pulp, the enzymatic hydrolysis temperature is 45-50 ℃, and the enzymatic hydrolysis time is 55-60 min.

[0012] In litchi pulp, the intercellular spaces are rich in protopectin and water-soluble pectin, which are the main reasons for the pulp's viscosity and poor flowability. Therefore, pectinase is needed to catalyze the hydrolysis of pectin molecular chains, reducing the viscosity of the litchi pulp and improving its flowability. Thus, pectinase is an essential component of complex liquefying enzymes and is fundamental to the degradation of litchi pulp. Pectin, acting as an intercellular "adhesive," becomes looser after degradation, providing a pathway for cellulase and hemicellulase to enter the cell wall. Cellulose, as the main skeletal structure of litchi pulp cell walls, results in high mechanical strength and difficulty in breaking down the cell walls. Cellulase can directionally hydrolyze cellulose chains, disrupting the rigid structure of the cell wall and achieving deep cell wall disruption. This disruption of the skeletal structure leads to rapid softening and disintegration of the pulp, improving pulp homogeneity, avoiding large undegraded particles, and ensuring a uniform and stable fermentation system. Hemicellulose, as the connecting chain between cellulose and pectin, is also an important component of the intact cell wall structure. Hemicellulase hydrolyzes the main and branched chains of hemicellulose, breaking down the intact cell wall structure. Working in conjunction with cellulase and pectinase, it achieves complete degradation of cell wall components, avoiding the problems of incomplete hydrolysis and uneven liquefaction associated with single enzymes. The natural aroma of lychee is mainly composed of terpenoids such as linalool, geraniol, and nerol, which mostly exist in a glycosidic-bound state, lacking aroma and difficult to release. β-glucosidase can specifically hydrolyze glycosidic bonds, converting bound aroma precursors into free aromas, significantly enhancing the natural fruit and floral aromas of lychee. After the aroma precursors are fully released, they can be transformed into a softer and more harmonious fermented ester and alcohol aroma during low-temperature complex fermentation, avoiding the unnatural flavors brought by exogenous flavorings. This allows the beverage to simultaneously possess the natural aroma of lychee, fermented alcohol aroma, and floral and fruity ester aromas, solving the problem of traditional lychee beverages having a thin aroma and relying on flavorings. In summary, the synergistic effect of pectinase, cellulase, and hemicellulase achieves efficient cell wall degradation, full liquefaction, and deep cell wall disruption, thereby increasing juice yield and substrate utilization. β-glucosidase specifically releases natural aroma precursors, enhancing the fruit aroma and flavor profile of the product. The four enzymes are compounded in a specific ratio to obtain a complex liquefying enzyme that can simultaneously meet the four core requirements of liquefaction, viscosity reduction, cell wall disruption, and aroma enhancement. This is highly compatible with subsequent low-temperature compound fermentation and vacuum-atmospheric pressure osmosis flavoring processes, ultimately achieving a harmonious flavor profile between the liquid phase of the beverage and the solid phase of the fruit pulp, resulting in a full-bodied taste and prominent natural aroma.

[0013] In step S4, the inoculation method of the compound yeast is as follows: Sake yeast and Kluyveromyces macrocarpa are dissolved separately in sterile water and activated at 25-30℃ for 20-30 minutes to obtain sake yeast liquid and Kluyveromyces macrocarpa liquid. Then, the two yeast liquids are mixed according to a predetermined live cell count ratio to obtain a compound yeast liquid, wherein the live cell count ratio of sake yeast to Kluyveromyces macrocarpa is 1:(1-2), and the inoculation amount of the compound yeast is 3.0 × 10⁻⁶. 6 ~8.0×10 6 CFU / mL.

[0014] In step S4, the fermentation temperature for low-temperature fermentation is 15–20°C, and the fermentation time is 30–48 h.

[0015] After the enzymatic hydrolysis of lychee pulp was significantly improved using compound liquefying enzymes, the urgent issue to be addressed is the fermentation of the lychee fermentation substrate. Existing post-enzymatic hydrolysis fermentation technologies for lychee pulp generally suffer from problems such as insufficient aroma complexity in single-yeast fermentation, weak activity at low temperatures, difficulty in controlling fermentation intensity, and easy masking of natural fruit aromas. Single-yeast fermentation only produces basic alcoholic aromas and a small amount of alcohols, with insufficient generation of esters, floral aromas, and fruity aroma compounds, resulting in a thin aroma, bland taste, and an inability to form a harmonious and full-bodied flavor system, failing to meet the demands of high-quality beverages. Single yeast metabolizes too quickly at normal temperatures, easily generating excessive ethanol, higher alcohols, and volatile acids, leading to problems such as a pronounced alcoholic taste, sourness, and a strong yeast flavor, severely masking the sweet and delicate aroma of lychee itself, resulting in the typical defect of "fermentation flavor stronger than fruit flavor." To avoid over-fermentation and preserve the aroma of lychees, the industry generally prefers low-temperature fermentation. However, single-yeast fermentation at low temperatures generally suffers from problems such as "slow start-up and incomplete fermentation," which leads to a significant decrease in aroma production and a cloyingly sweet taste due to incomplete sugar conversion.

[0016] To systematically address the aforementioned deficiencies, this invention introduces a compound yeast consisting of sake yeast and Kluwer yeast. The two yeasts complement each other functionally and synergistically in metabolism, fundamentally overcoming the technical bottleneck of single-yeast fermentation. Sake yeast is responsible for gentle, stable, and controllable basic fermentation, maintaining good activity even at low temperatures of 8–15 °C, providing a mellow, delicate, and non-irritating base aroma. Kluwer yeast can effectively synthesize floral and fruity esters such as ethyl acetate, isoamyl acetate, and phenylethyl acetate, significantly enriching the aroma layers and enhancing floral and sweet fruit aromas. Simultaneously, it synergistically strengthens characteristic lychee aroma compounds, making linalool, geraniol, and nerol more prominent and natural. During the compound fermentation process, sake yeast dominates sugar metabolism and system stability, while Kluwer yeast dominates aroma production and enhancement, achieving sufficient fermentation at low temperatures, moderate aroma production without over- or under-saturation, forming a three-dimensional compound aroma of "lychee fruit aroma + mellow mellow aroma + floral and fruity ester aroma," solving the industry problem of "flat aroma, abrupt taste, and insufficient fruit flavor" associated with single-yeast fermentation. In addition, sake yeast and Max Kluwer yeast have complementary nutritional requirements, and their synergy can effectively improve the utilization rate of carbon sources, nitrogen sources and trace elements in lychee pulp, resulting in more complete fermentation, lower residual sugar and a more stable system.

[0017] In step S5, the particle size of the fruit pulp is 3-5 mm, the mass ratio of lychee pulp to lychee fermentation liquid is 1:2 to 1:4, the vacuum degree of the vacuum-atmospheric pressure permeation treatment is -0.05 to -0.095 MPa, the vacuum holding time is 10 to 20 min, the atmospheric pressure treatment time is 15 to 30 min, and the above vacuum-atmospheric pressure permeation treatment process is repeated 1 to 2 times to obtain flavor-enhanced lychee pulp.

[0018] After solving the problems of enzymatic hydrolysis and fermentation, how to improve the taste of fruit pulp particles has become a new problem that urgently needs to be solved. In the existing technology, fruit juice beverages containing fruit pulp generally suffer from the core technical defects of having a rich flavor in the liquid phase fermentation and a weak original flavor of the fruit pulp in the solid phase, resulting in a significant difference in taste between the liquid and solid phases. This is mainly because: after enzymatic hydrolysis, the lychee pulp matrix is ​​fully broken down and liquefied, and soluble sugars and aroma precursors are completely released. After fermentation by compound yeast, the liquid phase is enriched with a large number of secondary flavor substances such as floral and fruit ester aromas and mellow fermented alcohol aromas, resulting in a full and rich fermented flavor. However, the lychee pulp particles added later only retain the original sweet and refreshing fruit aroma of lychee, do not participate in the enzymatic hydrolysis and fermentation reaction, and have no fermented flavor accumulation inside. In addition, existing technologies typically use methods such as atmospheric pressure soaking and stirring to mix the fermentation liquid with the fruit pulp particles. These methods can only achieve the fermentation liquid adhering to the surface of the fruit pulp particles. However, the internal structure of lychee pulp is dense, with a large number of tiny pores and air barrier layers. Under atmospheric pressure, the fermentation liquid is difficult to penetrate the pulp skin and seep into the pulp tissue. As a result, the pulp particles only have flavor on the surface, while the core of the pulp always retains its original bland flavor. It is impossible to achieve a uniform fusion of overall flavor, and the product has poor chewing texture.

[0019] To address the aforementioned issues, this invention innovatively introduces a vacuum-atmospheric pressure permeation process. Utilizing pressure difference, it drives the fermentation broth to deeply penetrate the fruit pulp tissue, eliminating the liquid-solid flavor difference at its source and achieving integrated flavor fusion. First, under a set vacuum condition, air is rapidly extracted from the pores of the lychee pulp tissue, eliminating air barriers and creating loose negative pressure permeation channels within the pulp. This breaks down the permeation barriers of the dense lychee pulp structure, solving the core problem of the fermentation broth's inability to penetrate deeply into the pulp under normal pressure, laying the structural foundation for the comprehensive penetration of fermented flavor substances. After the vacuum pressure is maintained, the environment is restored to normal pressure. Using the physical driving force of the internal and external pressure difference, the lychee fermentation broth, rich in complex fruit aromas and fermented mellow fragrance, is rapidly and evenly injected into the tiny pores of the pulp tissue, replacing the space previously occupied by air. This achieves comprehensive filling of the fermented flavor substances from the surface to the core of the pulp, completely resolving the layering defect where the pulp is tasteless inside and flavorful on the surface. Furthermore, due to the different compositions and structures of different lychee varieties, the required number of vacuum-atmospheric pressure permeation cycles varies. For example, for lychee products with high flesh firmness and low porosity, such as the Chicken Beak Lychee, it is necessary to increase the vacuum level, extend the vacuum-atmospheric pressure permeation treatment time, and appropriately increase the number of vacuum-atmospheric pressure permeation treatment cycles. For lychee products with low flesh firmness and high porosity, such as the Glutinous Rice Lychee, it is necessary to decrease the vacuum level, shorten the vacuum-atmospheric pressure permeation treatment time, and appropriately reduce the number of vacuum-atmospheric pressure permeation treatment cycles.

[0020] In addition, the present invention also provides a lychee-flavored beverage containing pulp, which is prepared using the aforementioned preparation process for a lychee-flavored beverage containing pulp.

[0021] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: 1. This invention uses a compound liquefying enzyme composed of "pectinase + cellulase + hemicellulase + β-glucosidase". Among them, "pectinase + cellulase + hemicellulase" work together to achieve efficient degradation of cell walls, full liquefaction, and deep cell wall disruption, thereby improving juice yield and substrate utilization. β-glucosidase specifically releases natural aroma precursors, enhancing the fruit aroma and flavor profile of the product. The compound liquefying enzyme obtained by blending the four enzymes in a specific ratio can simultaneously meet the four core requirements of liquefaction, viscosity reduction, cell wall disruption, and aroma enhancement, laying a good foundation for subsequent low-temperature compound fermentation and vacuum-atmospheric pressure osmosis aroma enhancement.

[0022] 2. This invention introduces a compound yeast composed of sake yeast and Kluwer yeast, whose functions are complementary and their metabolism synergistic. During the compound fermentation process, sake yeast dominates sugar metabolism and system stability, while Kluwer yeast dominates aroma production and enhancement. This achieves full fermentation at low temperatures, with moderate, non-overly rich, and non-suppressive aroma production, forming a three-dimensional complex aroma of "lychee fruit aroma + mellow mellow aroma + floral and fruity ester aroma," solving the industry problem of "flat aroma, abrupt taste, and insufficient fruit flavor" associated with single yeasts. In addition, the nutritional needs of sake yeast and Kluwer yeast are complementary, and their synergy can effectively improve the utilization rate of carbon sources, nitrogen sources, and trace elements in lychee pulp, resulting in more complete fermentation, lower residual sugar, and a more stable system.

[0023] 3. This invention innovatively introduces a vacuum-atmospheric pressure permeation process, which uses pressure difference to drive the fermentation liquid to deeply penetrate into the pulp tissue. The fermentation flavor substances fill the pulp from the surface to the core, eliminating the liquid-solid flavor difference at the source and achieving integrated fusion of the two-phase flavors. This completely improves the defects of traditional products, such as strong juice flavor, bland pulp, and uncoordinated liquid-solid flavors, and greatly enhances the chewiness and flavor uniformity. Attached Figure Description

[0024] Figure 1 The results of the pulp firmness test are for the examples and comparative examples.

[0025] Figure 2 The results of the pulp elasticity test are for the examples and comparative examples.

[0026] Figure 3 The chewability test results are for the examples and comparative examples.

[0027] Figure 4 The results of TSS tests inside the pulp are for both the example and comparative examples.

[0028] Figure 5 The results of the liquid-solid flavor difference test are shown for the examples and comparative examples. Detailed Implementation

[0029] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0030] In the specific embodiments of this application, the sources of various main raw materials are briefly described as follows: Lychee: Fresh chicken beak lychees purchased from the market are selected, free from rot and pests.

[0031] Pectinase: Purchased from Shandong Nuojie Biotechnology Co., Ltd., CAS No. 9032-75-1, food grade, enzyme activity 30000U / g.

[0032] Cellulase: Purchased from Chengdu Wanxiang Hongrun Biotechnology Co., Ltd., CAS No. 9012-54-8, food grade, enzyme activity 100000U / g.

[0033] Hemicellulase: Ningxia Xiasheng Industrial Group Co., Ltd., CAS No. 9025-56-3, food grade, enzyme activity 50000U / g.

[0034] β-glucosidase: purchased from Henan Ruisong Food Co., Ltd., CAS No. 9001-22-3, food grade, enzyme activity 50000U / g.

[0035] Sake yeast: Purchased from Shanghai Baocang Microbial Co., Ltd., Association No. 6 sake yeast, freeze-dried powder.

[0036] Kluyveromycin: purchased from China Industrial Microbial Culture Collection Center (CICC), accession number: CICC 33373, freeze-dried powder.

[0037] The technical solution of this application is as follows: A preparation process for a lychee-flavored beverage containing fruit pulp includes the following steps: S1. Select fresh, ripe lychees, wash, peel, and remove the pits to obtain lychee pulp; S2. Crush and pulp some of the lychee pulp, add compound liquefying enzyme for enzymatic hydrolysis, and obtain lychee liquefying pulp. S3. The litchi liquefied pulp is sterilized and then cooled to a low-temperature fermentation temperature to obtain litchi fermentation base material. S4. Inoculate the lychee fermentation substrate with compound yeast and obtain lychee fermentation liquid through low-temperature fermentation. The compound yeast is composed of sake yeast and Max Kluyveromyces. S5. Crush the remaining lychee pulp into pulp particles and soak them in the lychee fermentation liquid obtained in step S4. The soaking process adopts vacuum-atmospheric pressure osmosis treatment to allow the lychee fermentation liquid to enter the pulp tissue and obtain flavor-enhanced lychee pulp. S6. Mix and adjust the lychee fermentation liquid, flavor-enhancing lychee pulp, sugar source, acidity regulator, stabilizer, color protectant and water to obtain the blended liquid; S7. The prepared liquid is filled and sterilized, and after cooling, a lychee-flavored beverage containing fruit pulp is obtained.

[0038] The compound liquefying enzyme in step S2 is formed by combining pectinase, cellulase, hemicellulase and β-glucosidase in the following mass ratio: pectinase: cellulase: hemicellulase: β-glucosidase = 1: (0.4-0.6): (0.4-0.6): (0.1-0.2).

[0039] In step S2, the amount of compound liquefying enzyme added is 0.06%-0.18% of the mass of litchi pulp, the enzymatic hydrolysis temperature is 40-50 ℃, and the enzymatic hydrolysis time is 50-65 min.

[0040] Preferably, in step S2, the amount of compound liquefying enzyme added is 0.1%-0.15% of the mass of litchi pulp, the enzymatic hydrolysis temperature is 45-50 ℃, and the enzymatic hydrolysis time is 55-60 min.

[0041] In step S4, the inoculation method of the compound yeast is as follows: Sake yeast and Kluyveromyces macrocarpa are dissolved separately in sterile water and activated at 25-30℃ for 20-30 minutes to obtain sake yeast liquid and Kluyveromyces macrocarpa liquid. Then, the two yeast liquids are mixed according to a predetermined live cell count ratio to obtain a compound yeast liquid, wherein the live cell count ratio of sake yeast to Kluyveromyces macrocarpa is 1:(1-2), and the inoculation amount of the compound yeast is 3.0 × 10⁻⁶. 6 ~8.0×10 6 CFU / mL.

[0042] In step S4, the fermentation temperature for low-temperature fermentation is 15–20°C, and the fermentation time is 30–48 h.

[0043] In step S5, the particle size of the fruit pulp is 3-5 mm, the mass ratio of lychee pulp to lychee fermentation liquid is 1:2 to 1:4, the vacuum degree of the vacuum-atmospheric pressure permeation treatment is -0.05 to -0.095 MPa, the vacuum holding time is 10 to 20 min, the atmospheric pressure treatment time is 15 to 30 min, and the above vacuum-atmospheric pressure permeation treatment process is repeated 1 to 2 times to obtain flavor-enhanced lychee pulp.

[0044] In addition, the present invention also provides a lychee-flavored beverage containing pulp, which is prepared using the aforementioned preparation process for a lychee-flavored beverage containing pulp.

[0045] The present invention will be described in detail below through examples and comparative examples, but the scope of protection of the present invention is not limited to these examples. Unless otherwise specified, the chemical reagents and raw materials used in the following examples and comparative examples are all conventional commercially available products.

[0046] Example 1 A preparation process for a lychee-flavored beverage containing fruit pulp includes the following steps: S1. Select fresh, ripe lychees, wash, peel, and remove the pits to obtain 100 kg of lychee pulp; S2. Take 70 kg of litchi pulp, crush and pulp it to obtain litchi pulp. Prepare a compound liquefying enzyme according to the mass ratio of pectinase: cellulase: hemicellulase: β-glucosidase = 1:0.4:0.5:0.1. Dissolve the compound liquefying enzyme in sterile warm water at 30℃ and prepare a 1% (w / w) compound liquefying enzyme solution. Slowly add it to the litchi pulp and stir evenly for enzymatic hydrolysis. The enzymatic hydrolysis temperature is 40℃ and the enzymatic hydrolysis time is 55 min. Quickly heat the enzymatically hydrolyzed litchi pulp to 85℃ and keep it at that temperature for 60 s for enzyme inactivation treatment. After naturally cooling to room temperature, litchi liquefying pulp is obtained. The amount of compound liquefying enzyme added is 0.056 kg of litchi pulp mass. S3. The litchi liquefaction pulp obtained in step S2 is treated with pasteurization: sterilization temperature 90℃, heat preservation for 30s, after sterilization, it is rapidly cooled to 17℃ and kept at a constant temperature for 10min to obtain sterile and homogeneous litchi fermentation base. S4. Dissolve sake yeast and Kluwer yeast separately in sterile water, activate at 25℃ for 20 min to obtain sake yeast liquid and Kluwer yeast liquid. Then mix the two yeast liquids at a live cell ratio of 1:2 to obtain a compound yeast liquid. Inoculate the compound yeast liquid into the lychee fermentation substrate and ferment at 15℃ for 45 h to obtain lychee fermentation broth. The inoculation amount of the compound yeast is 8.0 × 10⁻⁶. 6 CFU / mL, after fermentation, the lychee fermentation liquid is heated to 90℃, kept warm for 30s to kill the yeast instantly, and then quickly cooled to 17℃ before entering the S5 maceration process. S5. Crush the remaining 30kg of lychee pulp into 3mm pulp particles. Place the pulp particles in the lychee fermentation liquid obtained in step S4 for immersion. The immersion process adopts vacuum-atmospheric pressure permeation treatment. The vacuum degree of vacuum-atmospheric pressure permeation treatment is -0.09 MPa, the vacuum holding time is 15 min, and the atmospheric pressure treatment time is 15 min. Repeat the above vacuum-atmospheric pressure permeation treatment process twice to obtain flavor-enhanced lychee pulp. The solid-liquid system composed of flavor-enhanced lychee pulp and the remaining lychee fermentation liquid is defined as the basic material system. S6. First, add 10kg of white sugar, 0.3kg of citric acid, 0.1kg of malic acid, 0.4kg of sodium alginate, and 0.1kg of ascorbic acid to 50kg of sterile warm water at 55℃. Stir at high speed until completely dissolved, and cool to room temperature to obtain an excipient mixture. Add the excipient mixture to the base material system and stir at low speed for 10 minutes at a stirring speed of 200r / min. Finally, add 39.1kg of sterile purified water and stir again to homogenize, so that the fruit pulp particles are evenly dispersed and the materials are fully integrated without layering or clumping, to obtain a homogeneous and stable formulation.

[0047] S7. The prepared liquid is aseptically filled using a hot filling process at a filling temperature of 85℃. The filling is then quickly sealed. Immediately after filling, a water bath terminal pasteurization process is performed. The sterilization parameters are: heating time of 5 minutes, constant temperature sterilization temperature of 90℃, and constant temperature sterilization time of 4 minutes. After sterilization, a segmented gradient cooling method is used to cool the liquid. First, the temperature is lowered to 50℃ at a rate of 2℃ / min and held for 5 minutes. Then, the temperature is lowered to 25℃ to obtain a lychee-flavored beverage containing fruit pulp.

[0048] Example 2 A preparation process for a lychee-flavored beverage containing fruit pulp includes the following steps: S1. Select fresh, ripe lychees, wash, peel, and remove the pits to obtain 100 kg of lychee pulp; S2. Take 80kg of lychee pulp, crush and pulp it to obtain lychee pulp. Prepare a compound liquefying enzyme according to the mass ratio of pectinase: cellulase: hemicellulase: β-glucosidase = 1:0.5:0.4:0.15. Dissolve the compound liquefying enzyme in sterile water at 30℃ and prepare a 1% (w / w) compound liquefying enzyme solution. Slowly add it to the lychee pulp and stir evenly for enzymatic hydrolysis. The enzymatic hydrolysis temperature is 50℃ and the enzymatic hydrolysis time is 60min. Quickly heat the enzymatically hydrolyzed lychee pulp to 85℃ and keep it at that temperature for 60s to inactivate the enzyme. After naturally cooling to room temperature, obtain lychee liquefying pulp. The amount of compound liquefying enzyme added is 0.12kg. S3. The litchi liquefaction pulp obtained in step S2 is treated with pasteurization: the sterilization temperature is 90℃, the temperature is kept for 30s, the temperature is rapidly cooled to 15℃ after sterilization, and the temperature is kept constant for 10min to obtain sterile and homogeneous litchi fermentation base. S4. Dissolve sake yeast and Kluwer yeast separately in sterile water, activate at 25℃ for 20 min to obtain sake yeast liquid and Kluwer yeast liquid. Then mix the two yeast liquids at a live cell ratio of 1:1.5 to obtain a compound yeast liquid. Inoculate the compound yeast liquid into the lychee fermentation substrate and ferment at 20℃ for 45 h to obtain lychee fermentation broth. The inoculation amount of the compound yeast is 8.0 × 10⁻⁶. 6 CFU / mL; After fermentation, the lychee fermentation liquid is heated to 90℃, kept warm for 30s to kill the yeast instantly, and then quickly cooled to 17℃ before entering the S5 impregnation process. S5. Crush the remaining 20kg of lychee pulp into 4mm pulp particles. Place the pulp particles in the lychee fermentation liquid obtained in step S4 for immersion. The immersion process adopts vacuum-atmospheric pressure permeation treatment. The vacuum degree of vacuum-atmospheric pressure permeation treatment is -0.09 MPa, the vacuum holding time is 15 min, and the atmospheric pressure treatment time is 15 min. Repeat the above vacuum-atmospheric pressure permeation treatment process once to obtain flavor-enhanced lychee pulp. The solid-liquid system composed of flavor-enhanced lychee pulp and the remaining lychee fermentation liquid is defined as the basic material system. S6. First, add 9kg of white sugar, 0.25kg of citric acid, 0.15kg of malic acid, 0.3kg of sodium alginate, and 0.1kg of ascorbic acid to 50kg of sterile warm water at 55℃. Stir at high speed until completely dissolved, and cool to room temperature to obtain an excipient mixture. Add the excipient mixture to the base material system and stir at low speed for 10 minutes at a stirring speed of 200r / min. Finally, add 40.2kg of sterile purified water and stir again to homogenize, so that the fruit pulp particles are evenly dispersed and the materials are fully integrated without layering or clumping, to obtain a homogeneous and stable formulation.

[0049] S7. The prepared liquid is aseptically filled using a hot filling process at a filling temperature of 85℃. The filling is then quickly sealed. Immediately after filling, a water bath terminal pasteurization process is performed. The sterilization parameters are: heating time of 5 minutes, constant temperature sterilization temperature of 90℃, and constant temperature sterilization time of 4 minutes. After sterilization, a segmented gradient cooling method is used to cool the liquid. First, the temperature is lowered to 50℃ at a rate of 2℃ / min and held for 5 minutes. Then, the temperature is lowered to 25℃ to obtain a lychee-flavored beverage containing fruit pulp.

[0050] Example 3 A preparation process for a lychee-flavored beverage containing fruit pulp includes the following steps: S1. Select fresh, ripe lychees, wash, peel, and remove the pits to obtain 100 kg of lychee pulp; S2. Take 60kg of litchi pulp, crush and pulp it to obtain litchi pulp. Prepare a compound liquefying enzyme according to the mass ratio of pectinase:cellulase:hemicellulase:β-glucosidase = 1:0.5:0.5:0.1. Dissolve the compound liquefying enzyme in sterile warm water at 30℃ and prepare a 1% (w / w) compound liquefying enzyme solution. Slowly add it to the litchi pulp and stir evenly for enzymatic hydrolysis. The enzymatic hydrolysis temperature is 45℃ and the enzymatic hydrolysis time is 65min. Quickly heat the enzymatically hydrolyzed litchi pulp to 85℃ and keep it at this temperature for 60s to inactivate the enzyme. After naturally cooling to room temperature, litchi liquefying pulp is obtained. The amount of compound liquefying enzyme added is 0.108kg. S3. The litchi liquefaction pulp obtained in step S2 is treated with pasteurization: the sterilization temperature is 90℃, the temperature is kept for 30s, the temperature is rapidly cooled to 25℃ after sterilization, and the temperature is kept constant for 10min to obtain sterile and homogeneous litchi fermentation base. S4. Dissolve sake yeast and Kluwer yeast separately in sterile water, activate at 25℃ for 20 min to obtain sake yeast liquid and Kluwer yeast liquid. Then mix the two yeast liquids at a live cell ratio of 1:1 to obtain a compound yeast liquid. Inoculate the compound yeast liquid into the lychee fermentation substrate and ferment at 20℃ for 48 h to obtain lychee fermentation broth. The inoculation amount of the compound yeast is 8.0 × 10⁻⁶. 6 CFU / mL, after fermentation, the lychee fermentation liquid is heated to 90℃, kept warm for 30s to kill the yeast instantly, and then quickly cooled to 17℃ before entering the S5 maceration process. S5. Crush the remaining 40kg of lychee pulp into 3mm pulp particles. Place the pulp particles in the lychee fermentation liquid obtained in step S4 for immersion. The immersion process adopts vacuum-atmospheric pressure permeation treatment. The vacuum degree of vacuum-atmospheric pressure permeation treatment is -0.09 MPa, the vacuum holding time is 15 min, and the atmospheric pressure treatment time is 15 min. Repeat the above vacuum-atmospheric pressure permeation treatment process twice to obtain flavor-enhanced lychee pulp. The solid-liquid system composed of flavor-enhanced lychee pulp and the remaining lychee fermentation liquid is defined as the basic material system. S6. First, add 15kg of white sugar, 0.4kg of citric acid, 0.2kg of malic acid, 0.5kg of sodium alginate, and 0.2kg of ascorbic acid to 50kg of sterile warm water at 55℃. Stir at high speed until completely dissolved, and cool to room temperature to obtain an excipient mixture. Add the excipient mixture to the base material system and stir at low speed for 15 minutes at a stirring speed of 300r / min. Finally, add 33.7kg of sterile purified water and stir again to homogenize, so that the fruit pulp particles are evenly dispersed and the materials are fully integrated without layering or clumping, to obtain a homogeneous and stable formulation.

[0051] S7. The prepared liquid is aseptically filled using a hot filling process at a filling temperature of 85℃. The filling is then quickly sealed. Immediately after filling, a water bath terminal pasteurization process is performed. The sterilization parameters are: heating time of 5 minutes, constant temperature sterilization temperature of 90℃, and constant temperature sterilization time of 4 minutes. After sterilization, a segmented gradient cooling method is used to cool the liquid. First, the temperature is lowered to 50℃ at a rate of 2℃ / min and held for 5 minutes. Then, the temperature is lowered to 25℃ to obtain a lychee-flavored beverage containing fruit pulp.

[0052] Example 4 A preparation process for a lychee-flavored beverage containing fruit pulp includes the following steps: S1. Select fresh, ripe lychees, wash, peel, and remove the pits to obtain 100 kg of lychee pulp; S2. Take 70 kg of litchi pulp, crush and pulp it to obtain litchi pulp. Prepare a compound liquefying enzyme according to the mass ratio of pectinase: cellulase: hemicellulase: β-glucosidase = 1:0.6:0.4:0.15. Dissolve the compound liquefying enzyme in sterile warm water at 30℃ and prepare a 1% (w / w) compound liquefying enzyme solution. Slowly add it to the litchi pulp and stir evenly for enzymatic hydrolysis. The enzymatic hydrolysis temperature is 45℃ and the enzymatic hydrolysis time is 60 min. The enzymatically hydrolyzed litchi pulp is rapidly heated to 85℃ and kept at this temperature for 60 s for enzyme inactivation treatment. After naturally cooling to room temperature, litchi liquefying pulp is obtained. The amount of compound liquefying enzyme added is 0.126 kg. S3. The litchi liquefaction pulp obtained in step S2 is treated with pasteurization: the sterilization temperature is 90℃, the temperature is kept for 30s, the temperature is rapidly cooled to 15℃ after sterilization, and the temperature is kept constant for 10min to obtain sterile and homogeneous litchi fermentation base. S4. Dissolve sake yeast and Kluwer yeast separately in sterile water, activate at 25℃ for 20 min to obtain sake yeast liquid and Kluwer yeast liquid. Then mix the two yeast liquids at a live cell ratio of 1:1.5 to obtain a compound yeast liquid. Inoculate the compound yeast liquid into the lychee fermentation substrate and ferment at 18℃ for 45 h to obtain lychee fermentation broth. The inoculation amount of the compound yeast is 7.0 × 10⁻⁶. 6 CFU / mL, after fermentation, the lychee fermentation liquid is heated to 90℃, kept warm for 30s to kill the yeast instantly, and then quickly cooled to 17℃ before entering the S5 maceration process. S5. Crush the remaining 30kg of lychee pulp into 4mm pulp particles. Place the pulp particles in the lychee fermentation liquid obtained in step S4 for immersion. The immersion process adopts vacuum-atmospheric pressure osmosis treatment. The vacuum degree of vacuum-atmospheric pressure osmosis treatment is -0.09 MPa, the vacuum holding time is 18 min, and the atmospheric pressure treatment time is 20 min. Repeat the above vacuum-atmospheric pressure osmosis treatment process twice to obtain flavor-enhanced lychee pulp. The solid-liquid system composed of flavor-enhanced lychee pulp and the remaining lychee fermentation liquid is defined as the basic material system. S6. First, add 10kg of white sugar, 0.3kg of citric acid, 0.1kg of malic acid, 0.4kg of sodium alginate, and 0.1kg of ascorbic acid to 50kg of sterile warm water at 55℃. Stir at high speed until completely dissolved, and cool to room temperature to obtain an excipient mixture. Add the excipient mixture to the base material system and stir at low speed for 10-15 minutes at a stirring speed of 200-300 r / min. Finally, add 49.1kg of sterile purified water and stir again to homogenize, so that the fruit pulp particles are evenly dispersed and the materials are fully integrated without layering or clumping, to obtain a homogeneous and stable formulation.

[0053] S7. The prepared liquid is aseptically filled using a hot filling process at a filling temperature of 85℃. The filling is then quickly sealed. Immediately after filling, a water bath terminal pasteurization process is performed. The sterilization parameters are: heating time of 5 minutes, constant temperature sterilization temperature of 90℃, and constant temperature sterilization time of 4 minutes. After sterilization, a segmented gradient cooling method is used to cool the liquid. First, the temperature is lowered to 50℃ at a rate of 2℃ / min and held for 5 minutes. Then, the temperature is lowered to 25℃ to obtain a lychee-flavored beverage containing fruit pulp.

[0054] Comparative Example 1 Compared with Example 4, in step S2, the compound liquefying enzyme was prepared with a mass ratio of pectinase:cellulase:hemicellulase = 1:0.6:0.4. All other steps and parameters were exactly the same as in Example 4.

[0055] Comparative Example 2

[0056] Compared with Example 4, in step S2, the compound liquefying enzyme was prepared with a mass ratio of pectinase:cellulase:hemicellulase:β-glucosidase = 1:0.6:0.4:0.3. The other steps and parameters were exactly the same as in Example 4.

[0057] Comparative Example 3

[0058] Compared with Example 4, the amount of compound liquefying enzyme added in step S2 is 0.03% of the mass of litchi pulp, and the other steps and parameters are exactly the same as in Example 4.

[0059] Comparative Example 4

[0060] Compared with Example 4, the amount of compound liquefying enzyme added in step S2 is 0.2% of the mass of litchi pulp, and the other steps and parameters are exactly the same as in Example 4.

[0061] Comparative Example 5 Compared with Example 4, the ratio of live sake yeast to Kluyveromyces margaritifera in step S4 is 2:1, and the other steps and parameters are exactly the same as in Example 4.

[0062] Comparative Example 6 Compared with Example 4, the ratio of live sake yeast to Kluyveromyces margaritifera in step S4 is 1:3, and the other steps and parameters are exactly the same as in Example 4.

[0063] Comparative Example 7 Compared with Example 4, the inoculation amount of compound yeast in step S4 was 1.0 × 10⁻⁶. 6 The CFU / mL concentration was the same as in Example 4, with all other steps and parameters being identical.

[0064] Comparative Example 8 Compared with Example 4, the inoculation amount of compound yeast in step S4 was 1.0 × 10⁻⁶. 7 The CFU / mL concentration was the same as in Example 4, with all other steps and parameters being identical.

[0065] Comparative Example 9 Compared with Example 4, step S5 uses atmospheric pressure osmosis treatment, while the other steps and parameters are exactly the same as in Example 4.

[0066] Comparative Example 10 Compared with Example 4, the vacuum-atmospheric pressure permeation treatment in step S5 is performed once, while the other steps and parameters are exactly the same as in Example 4.

[0067] Comparative Example 11 Compared with Example 4, the vacuum-atmospheric pressure permeation treatment in step S5 is performed 4 times, while the other steps and parameters are exactly the same as in Example 4.

[0068] Evaluation index system and measurement methods To systematically and objectively evaluate the quality differences of the lychee pulp beverages obtained in each embodiment and comparative example, a six-dimensional evaluation index system covering sensory quality, physicochemical properties, flavor compounds, textural properties, stability, and liquid-solid flavor harmony was established. The methods for measuring each index are as follows: (1) Sensory evaluation In accordance with GB / T 10220-2012 and GB / T 12312-2012, a professional sensory evaluation team of 10 people (half male and half female, aged 22–35, all trained in sensory analysis) was formed. In a standard sensory analysis room (temperature 20±2℃, relative humidity 50–60%, white light source), a 100-point scoring method was used to evaluate the sensory qualities across five dimensions: color (20 points), aroma (25 points), taste (25 points), texture (20 points), and overall liking (10 points). The highest and lowest scores were discarded, and the arithmetic mean was taken.

[0069] (2) Physicochemical indicators Soluble solids (TSS): Abbe refractometer method, determined at 20℃, in accordance with GB / T 12143-2008; Total acidity: acid-base titration method, using phenolphthalein as indicator, titrated with 0.1 mol / L NaOH, the result is expressed as citric acid, in accordance with GB 12456-2021; pH value: directly measured with a precision acidity meter; Pulp content: The pulp was filtered through a 0.5mm standard sieve, washed with deionized water, drained through gauze for 2 minutes, and then weighed to calculate the mass fraction.

[0070] (3) Flavor compound analysis Key volatile flavor compounds in beverages were determined using headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). The chromatographic column was a DB-WAX (60 m × 0.25 mm × 0.25 μm); the temperature program was: 40 °C for 3 min, increased to 120 °C at 4 °C / min, then increased to 230 °C at 8 °C / min and held for 5 min; the MS detector was an EI source with an electron energy of 70 eV and a scan range of m / z 35–350. 2-Octanol was used as an internal standard for quantification. The focus was on monitoring characteristic aroma components of litchi (linalool, geraniol, nerol) and fermentation-characteristic esters (ethyl acetate, isoamyl acetate, phenethyl acetate) and ethanol.

[0071] (4) Determination of textural properties TPA (Texture Profile Analysis) tests were performed using a food texture analyzer. Individual fruit pulp particles were placed under a P / 0.5-inch cylindrical probe at a test rate of 1.0 mm / s, a compression ratio of 50%, a trigger load of 5 g, and an interval of 5 s. Hardness, elasticity, and chewiness data were recorded.

[0072] (5) Stability Indicators Centrifugation sedimentation rate: Take 50 mL of sample solution into a centrifuge tube, centrifuge at 3000 r / min for 10 min, and read the sedimentation volume fraction (%). Room temperature stratification rate: The sample is placed in a transparent graduated tube and left to stand at 25°C for 7 days. The percentage (%) of the height of the supernatant is measured. The lower the value, the better the suspension stability.

[0073] (6) Evaluation of the balance between liquid and solid flavors Two independent evaluations were conducted by the same sensory evaluation panel: ①Score after directly drinking the juice; ②Score after chewing the fruit pulp particles individually.

[0074] The absolute value of the difference between the two scores is used as the "liquid-solid flavor difference score" (out of 10, with a higher score for a larger difference). A higher score indicates a more severe separation between the liquid and solid phase flavors and a poorer harmony.

[0075] Performance Test Results and Analysis The test results are shown in Tables 1-3. Figures 1-5 As shown.

[0076] As shown in Tables 1-3, Examples 1-3 all achieved high sensory scores of 89-91 points. Example 4, in particular, achieved the best results in core indicators such as aroma (24 points), taste (24 points), centrifugal sedimentation rate (3.8%), 7-day stratification rate (4.2%), pulp firmness (288 g), and liquid-solid flavor difference (1.0 point). This demonstrates that the optimal enzyme addition (0.126 kg, 0.18%), yeast ratio (1:1.5), and inoculum size (7.0 × 10⁻⁶) used in Example 4 were optimal. 6 The optimal process window within the scope of this invention is defined by the parameter combination of "CFU / mL, fermentation at 18 ℃ for 45 h, and three vacuum-atmospheric pressure cycles".

[0077] Table 1. Sensory and Physicochemical Indicator Test Results Example 1 90 18 22 23 18 9 10.8 0.30 3.9 16 Example 2 91 18 23 23 18 9 11.0 0.29 4.0 14 Example 3 89 17 22 22 18 10 12.0 0.32 3.9 20 Example 4 95 19 24 24 19 9 11.2 0.28 4.0 18 Comparative Example 1 72 17 15 18 16 6 10.5 0.27 4.1 18 Comparative Example 2 68 16 14 17 15 6 10.6 0.26 4.1 18 Comparative Example 3 65 15 14 17 12 7 9.8 0.25 4.0 16 Comparative Example 4 66 16 15 17 13 5 10.3 0.24 4.2 18 Comparative Example 5 70 17 16 17 15 5 11.5 0.22 4.2 18 Comparative Example 6 69 17 15 16 15 6 10.9 0.42 3.5 18 Comparative Example 7 67 17 14 17 14 5 11.8 0.20 4.3 18 Comparative Example 8 64 14 13 16 13 8 10.6 0.45 3.6 18 Comparative Example 9 71 17 16 17 16 5 11.0 0.28 4.0 18 Comparative Example 10 76 18 19 19 17 3 11.1 0.28 4.0 18 Comparative Example 11 68 16 15 17 14 6 11.0 0.28 4.0 18 Example 4 (a four-enzyme blend, with β-glucosidase accounting for 0.15%) achieved a total sensory score of 95, significantly better than the other comparative examples. The aroma score was 24, with linalool content reaching 1280 μg / L and geraniol 360 μg / L, both at high levels. This indicates that β-glucosidase effectively hydrolyzed the glycoside-bound aroma precursors, synergistically amplifying the characteristic floral aroma of lychee with the fermentation of the compound yeast.

[0078] Comparative Example 1 (without β-glucosidase) scored only 15 points in aroma. Linalool (420 μg / L) and geraniol (110 μg / L) were reduced by 67.2% and 69.4% respectively compared to Example 4, and the total ester content also decreased significantly, resulting in "weak fruit aroma and single aroma layers". At the same time, the centrifugation sedimentation rate was 8.5% and the 7-day stratification rate was 12.0%, which were higher than those of Example 4 (3.8% and 4.2%), proving that β-glucosidase also contributes to the stability of the system.

[0079] Comparative Example 2 (with an excessively high β-glucosidase ratio of 0.3) had a total sensory score of 68, with aroma at 14 and taste at 17. Although the linalool content (580 μg / L) was higher than that of Comparative Example 1, the centrifugal sedimentation rate of 9.2% and the 7-day stratification rate of 14.0% were the highest among all samples. This indicates that excessive enzyme protein residue and excessive hydrolysis damaged the colloidal stability and produced trace amounts of off-flavor substances, resulting in an imbalance of flavor.

[0080] Comparative Example 3 (enzyme addition 0.03%) had an insufficient enzyme content, resulting in incomplete cell wall degradation and a tissue state score of only 12 points; its TSS was 9.8%, lower than that of Example 4 (11.2%), with low juice yield, high pulp viscosity, centrifugal sedimentation rate of 11.0%, and uneven and thick taste.

[0081] Comparative Example 4 (enzyme addition 0.2%) showed an increase in fine debris due to excessive enzymatic hydrolysis, with a centrifugal sedimentation rate of 13.5%, a 7-day stratification rate of 18.0%, and a slightly lower TSS of 10.3%, resulting in a bland taste. This demonstrates that the enzyme amount needs to be precisely controlled between 0.1% and 0.15%.

[0082] Table 2. Test results of key flavor compounds and stability indicators Example 1 1180 320 650 400 820 4.5 5.0 Example 2 1200 335 680 410 840 4.2 4.8 Example 3 1150 310 640 390 800 5.2 5.5 Example 4 1280 360 720 450 880 3.8 4.2 Comparative Example 1 420 110 380 220 750 8.5 12.0 Comparative Example 2 580 150 450 280 720 9.2 14.0 Comparative Example 3 380 95 320 180 680 11.0 15.5 Comparative Example 4 450 120 350 200 700 13.5 18.0 Comparative Example 5 680 180 1250 680 1850 6.5 8.0 Comparative Example 6 1580 420 520 780 520 7.2 9.5 Comparative Example 7 350 90 280 160 320 9.0 11.0 Comparative Example 8 520 140 980 620 1650 10.2 13.5 Comparative Example 9 1100 310 680 420 860 5.0 5.5 Comparative Example 10 1180 330 700 435 870 4.5 5.0 Comparative Example 11 1080 290 660 400 850 8.8 11.5 Example 4 (Sake yeast: Kluyveromyces martensii = 1:1.5, inoculum size 7.0 × 10⁻⁶) 6 The CFU / mL content is 880 mg / L, which is moderate; the ethyl acetate is 720 μg / L and the isoamyl acetate is 450 μg / L, which, together with linalool and geraniol, form a harmonious three-dimensional flavor of "fruity aroma + alcoholic aroma + ester aroma". The aroma score is 24 points and the taste score is 24 points.

[0083] Comparative Example 5 (Sake Yeast: Kluyveromyces = 2:1) showed a surge in ethanol content to 1850 mg / L, ethyl acetate to 1250 μg / L, and isoamyl acetate to 680 μg / L. This resulted in excessive accumulation of aroma compounds, causing the aroma score to drop to 16 points and the taste score to 17 points. The result was a defect where the aroma of sake masked the fruit aroma and the taste was sweet and heavy.

[0084] Comparative Example 6 (Sake Yeast: Kluyveromyces = 1:3), although linalool (1580 μg / L) and isoamyl acetate (780 μg / L) increased, ethanol was only 520 mg / L, total acid rose to 0.42%, pH dropped to 3.5, sourness was prominent, the taste score was only 16 points, and the flavor was thin and uncoordinated.

[0085] Comparative Example 7 (inoculation dose 1.0 × 10⁻⁶) 6 Due to insufficient viable bacteria (CFU / mL), fermentation started slowly, with only 320 mg / L of ethanol, 0.20% total acid, pH 4.3, and high residual sugar leading to excessive sweetness. The aroma score was 14 points, and the content of all flavor substances was at the lowest level.

[0086] Comparative Example 8 (inoculation dose 1.0 × 10⁻⁶) 7 The fermentation rate was too fast (CFU / mL), with ethanol at 1650 mg / L and ethyl acetate at 980 μg / L. However, the color score dropped to 14 (darkness), the centrifugation sedimentation rate was 10.2%, cell debris caused turbidity, and the aroma score was 13 (pungent off-odor). Data confirms an inoculum size of 3.0 × 10⁻⁶. 6 –8.0×10 6 The optimal window is CFU / mL.

[0087] Table 3. Test results of textural properties and liquid-solid flavor penetration. Example 1 278 2.85 0.82 9.5 1.8 Example 2 282 2.90 0.85 9.8 1.5 Example 3 275 2.80 0.80 9.6 1.9 Example 4 288 2.98 0.90 10.5 1.0 Comparative Example 1 280 2.88 0.84 9.8 1.6 Comparative Example 2 278 2.86 0.83 9.7 1.7 Comparative Example 3 292 2.95 0.90 9.9 1.5 Comparative Example 4 276 2.84 0.82 9.6 1.8 Comparative Example 5 281 2.87 0.84 10.0 1.4 Comparative Example 6 279 2.86 0.83 9.9 1.5 Comparative Example 7 283 2.89 0.85 10.1 1.3 Comparative Example 8 277 2.85 0.82 9.8 1.6 Comparative Example 9 298 3.02 0.95 3.2 7.8 Comparative Example 10 291 2.96 0.91 6.8 4.5 Comparative Example 11 142 1.42 0.32 10.8 1.8 Example 4 (vacuum-atmospheric pressure cycling 3 times): the TSS in the pulp reached 10.5%, which is close to the TSS in the liquid phase (11.2%). The liquid-solid flavor difference score was only 1.0 out of 10, indicating that the flavor substances have fully penetrated into the pulp core and the flavor of the liquid and solid phases is highly uniform. At the same time, the pulp firmness was 288g, elasticity was 2.98mm, and chewiness was 0.90mJ, maintaining a good crisp and chewy texture.

[0088] Comparative Example 9 (pure atmospheric pressure osmosis): the TSS inside the pulp was only 3.2%, which was 7.8 percentage points different from the liquid phase. The liquid-solid flavor difference score was as high as 7.8 points. The layering defect of "the juice is flavorful, but the pulp is bland" was obvious when chewing. Although the pulp firmness was the highest at 298 g, the flavor penetration failed.

[0089] Comparative Example 10 (only 1 cycle) had an internal TSS of 6.8% and a liquid-solid flavor difference of 4.5 points, which was an improvement over Comparative Example 9 but still showed obvious stratification.

[0090] Although the internal TSS of Comparative Example 11 (4 cycles) reached 10.8%, the flesh firmness dropped sharply by 142g (50.7% lower than Example 4), the elasticity was 1.42mm, the chewiness was 0.32mJ, and the flesh was soft and mushy, losing its crispness; moreover, the centrifugal sedimentation rate was 8.8% and the 7-day stratification rate was 11.5%, and the internal juice was released after cell damage, leading to a deterioration in the stability of the system.

[0091] Figures 1-5 The study visually demonstrates the significant impact of the infiltration process on indicators such as pulp firmness, elasticity, chewiness, internal TSS of the pulp, and liquid-solid flavor difference score.

[0092] from Figure 1 It can be seen that the flesh firmness of Examples 1–4 and Comparative Examples 1–10 is within the normal range. The flesh firmness of Comparative Example 9 is slightly higher, but combined with… Figure 4 (Internal TSS was only 3.2%), indicating that atmospheric pressure osmosis could not allow the fermentation liquid to penetrate into the pulp. Although the pulp was "firm," it was "tasteless," a typical defective state of "texture retention but flavor failure." Comparative Example 11 showed a sharp drop in firmness of 50.7%, which is the most crucial evidence of textural damage. The repeated negative pressure impact of four vacuum-atmospheric pressure cycles caused excessive rupture of the pulp cell walls and collapse of the fibrous structure, resulting in soft and mushy pulp.

[0093] from Figure 2 It can be seen that the elasticity of the pulp in Examples 1-4 and Comparative Examples 1-10 is within the normal range, with Comparative Example 9 exhibiting the highest elasticity. This may be due to the maximum preservation of pulp elasticity through atmospheric pressure osmosis. However, the elasticity of Comparative Example 11 is significantly reduced. Figure 1The sudden drop in hardness corroborates each other, indicating that repeated vacuum-atmospheric pressure cycling not only damages hardness but also destroys the elastic recovery structure of the pulp.

[0094] from Figure 3 It can be seen that the chewiness of the pulp in Examples 1-4 and Comparative Examples 1-10 is within the normal range. Among them, Comparative Example 9 has the highest chewiness, but combined with... Figure 5 It can be seen that its liquid-solid flavor difference score is as high as 7.8 points, indicating that although consumers can chew it, they are chewing "bland and tasteless pulp," resulting in a disjointed experience. Furthermore, Comparative Example 11 suffers from a severe loss of chewiness; consumers will find it "soft and boneless," a stark contrast to the "crisp and chewy texture" of Examples 1-4 (especially Example 4). Figure 1 and Figure 2 The sharp drop in hardness and elasticity corroborates each other, indicating that repeated vacuum-atmospheric pressure cycling not only damages hardness and elasticity, but also destroys the chewiness of the fruit pulp, severely reducing the taste of fruit pulp beverages.

[0095] from Figure 4 It can be seen that the difference between the TSS of soluble solids inside the pulp and the TSS of the liquid phase in Examples 1-4 is low, proving that the three vacuum-atmospheric pressure cycles have allowed the flavor substances such as sugars, acids, esters, and alcohols in the fermentation broth to penetrate from the surface of the pulp to the core, achieving a consistent flavor load inside and out. The internal TSS of Comparative Examples 1-8 is normal, indicating that these comparative examples use the same permeation process (3 cycles) as Example 4. The only difference is in the enzymatic hydrolysis or fermentation parameters, so the solid phase flavor load is similar, but the liquid phase flavor is different. Comparative Example 9 has the lowest TSS of all samples, with a reduction of up to 69.5% compared to Example 4, proving the irreplaceable nature of the vacuum-atmospheric pressure permeation process. Under atmospheric pressure, the fermentation broth only adheres to the surface of the pulp and cannot penetrate the dense porous structure of the lychee pulp, resulting in "flavor on the surface and no flavor in the core". The single-cycle process of Comparative Example 10 showed a 112.5% ​​increase in internal TSS compared to Comparative Example 9, but still a 35.2% decrease compared to Example 4, demonstrating the significant effect of the vacuum-atmospheric pressure permeation process. However, a single cycle was insufficient to achieve deep permeation, and flavor stratification remained evident. The internal TSS of Comparative Example 11 was even slightly higher than that of Example 4, but combined with... Figure 1 – Figure 3 It can be seen that this is due to "over-penetration" at the cost of sacrificing texture. The pulp fibers have been destroyed, and although the internal TSS is high, the texture is soft and mushy, resulting in a sharp drop in the user experience.

[0096] from Figure 5It can be seen that the liquid-solid flavors of Examples 1-4 are highly harmonious, allowing consumers to experience the same fermented aroma and lychee fruit fragrance as when chewing the pulp. Comparative Examples 1-8 received lower scores, similar to Example 4, further demonstrating that the poor liquid-solid flavor is mainly determined by the infiltration process, rather than enzymatic hydrolysis or fermentation parameters. As long as the infiltration process is correct, even slight deviations in enzyme / yeast parameters can still achieve a high level of solid-phase flavor loading.

[0097] Comparative Example 9 (7.8 points) had the highest score of all samples, increasing by 680% compared to Example 4. This again highlights the core problem of existing technologies: "strong flavor in the liquid phase and weak flavor in the solid phase," which atmospheric pressure osmosis cannot solve at all. Comparative Example 10 reduced the score by 42.3% after one cycle compared to Comparative Example 9, showing a significant improvement, but it was still 350% higher than Example 4, indicating that a single cycle can only partially improve flavor stratification and cannot meet the harmonization requirements of commercial products. Comparative Example 11 had a lower score, indicating a high flavor load, but combined with... Figure 1 – Figure 3 The fruit pulp is already soft and mushy, so even with a high flavor load, consumers will not have a "pleasant chewing experience" and the fruit pulp beverage cannot ultimately achieve the goal of being "delicious and tasty".

[0098] In summary, based on the above multidimensional evaluation index data, this invention, through the synergistic process of "precise compounding of four enzymes + complementary function of two yeasts + vacuum-atmospheric pressure circulation permeation", enables the product to achieve excellent levels in terms of total sensory score (≥89), content of characteristic aroma substances (linalool ≥1150 μg / L), fermentation ester aroma (ethyl acetate ≥640 μg / L), suspension stability (centrifugal sedimentation rate ≤5.2%), liquid-solid flavor harmony (flavor difference score ≤1.9), and pulp texture (firmness ≥275g).

[0099] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A preparation process for a lychee-flavored beverage containing fruit pulp, characterized in that, Includes the following steps: S1. Select fresh, ripe lychees, wash, peel, and remove the pits to obtain lychee pulp; S2. Crush and pulp some of the lychee pulp, add compound liquefaction enzyme for enzymatic hydrolysis and liquefaction, and obtain lychee liquefaction pulp. S3. The litchi liquefied pulp is sterilized and then cooled to a low-temperature fermentation temperature to obtain litchi fermentation base material. S4. Inoculate the lychee fermentation substrate with compound yeast and obtain lychee fermentation liquid through low-temperature fermentation. The compound yeast is composed of sake yeast and Max Kluyveromyces. S5. Crush the remaining lychee pulp into pulp particles and soak them in the lychee fermentation liquid obtained in step S4. The soaking process adopts vacuum-atmospheric pressure osmosis treatment to allow the lychee fermentation liquid to enter the pulp tissue and obtain flavor-enhanced lychee pulp. S6. Mix and adjust the lychee fermentation liquid, flavor-enhancing lychee pulp, sugar source, acidity regulator, stabilizer, color protectant and water to obtain the blended liquid; S7. The prepared liquid is filled and sterilized, and after cooling, a lychee-flavored beverage containing fruit pulp is obtained.

2. The preparation process of the lychee-flavored beverage containing fruit pulp according to claim 1, characterized in that, In step S2, the compound liquefying enzyme is formed by combining pectinase, cellulase, hemicellulase and β-glucosidase in the following mass ratio: pectinase: cellulase: hemicellulase: β-glucosidase = 1: (0.4-0.6): (0.4-0.6): (0.1-0.2).

3. The preparation process of the lychee-flavored beverage containing fruit pulp according to claim 1, characterized in that, In step S2, the amount of compound liquefying enzyme added is 0.06%-0.18% of the mass of litchi pulp, the enzymatic hydrolysis temperature is 40-50 ℃, and the enzymatic hydrolysis time is 50-65 min.

4. The preparation process of the lychee-flavored beverage containing fruit pulp according to claim 3, characterized in that, In step S2, the amount of compound liquefying enzyme added is 0.1%-0.15% of the mass of litchi pulp, the enzymatic hydrolysis temperature is 45-50 ℃, and the enzymatic hydrolysis time is 55-60 min.

5. The preparation process of the lychee-flavored beverage containing pulp according to claim 1, characterized in that, In step S4, the inoculation method of the compound yeast is as follows: Sake yeast and Kluwer yeast are dissolved separately in sterile water and activated at 25-30℃ for 20-30 minutes to obtain sake yeast liquid and Kluwer yeast liquid. Then, the two yeast liquids are mixed according to a set live cell count ratio to obtain a compound yeast liquid, wherein the live cell count ratio of sake yeast to Kluwer yeast is 1:(1-2), and the inoculation amount of the compound yeast is 3.0 × 10⁻⁶. 6 ~8.0×10 6 CFU / mL.

6. The preparation process of the lychee-flavored beverage containing fruit pulp according to claim 1, characterized in that, In step S4, the fermentation temperature for low-temperature fermentation is 15–20°C, and the fermentation time is 30–48 h.

7. The preparation process of the lychee-flavored beverage containing pulp according to claim 1, characterized in that, In step S5, the particle size of the fruit pulp is 3-5 mm, and the mass ratio of lychee pulp to lychee fermentation liquid is 1:2 to 1:

4.

8. The preparation process of the lychee-flavored beverage containing pulp according to claim 1, characterized in that, In step S5, the vacuum degree of the vacuum-atmospheric pressure permeation treatment is -0.05 to -0.095 MPa, the vacuum holding time is 10 to 20 min, the atmospheric pressure treatment time is 15 to 30 min, and the above vacuum-atmospheric pressure permeation treatment process is repeated 1 to 2 times to obtain flavor-enhanced lychee pulp.

9. A lychee-flavored beverage containing fruit pulp, characterized in that, The lychee-flavored beverage containing pulp is prepared using the preparation process of the lychee-flavored beverage containing pulp as described in any one of claims 1-8.

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