Co-production preparation method of fermented red date fruit suction puree

Abstract

The invention relates to the technical field of food processing, in particular to a co-production preparation method of fermented red date fruit-suction fruit puree, which comprises the following steps: pretreating fresh red dates, performing two-stage crushing, inoculating a three-layer embedded complex microbial inoculant of plant lactobacillus, saccharomyces cerevisiae and acetobacter, performing anaerobic-aerobic staged fermentation, performing centrifugal separation to obtain supernate and precipitate, and drying the supernate to obtain the fermented red date fruit-suction fruit puree. Respectively performing differentiated blending to obtain a fruit absorbing base solution and a fruit paste base solution, and then performing compound sterilization, sterile filling and irradiation sterilization to obtain a finished product. According to the method, 100% utilization of the red date raw material is achieved, low-sugar, high-fiber and probiotic-rich fruit absorption and fruit paste double products are synchronously obtained, the resource utilization rate is high, and the method is suitable for industrial production.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, specifically to a method for the co-production of fermented jujube fruit pulp. Background Technology

[0002] Red dates are rich in polysaccharides, flavonoids, vitamins, minerals, and other nutrients, and have health benefits such as tonifying the spleen and stomach, nourishing blood, and calming the mind. They are a traditional Chinese food and medicine source. Currently, processed red date products mainly include dried red dates, red date juice, red date cakes, and red date wine. However, these products suffer from problems such as simple processing methods, low resource utilization, and low added value. For example, in the traditional red date juice production process, a large amount of date pulp residue is discarded, resulting in a waste of nutrients; while red date puree products are mostly made by direct grinding, resulting in a rough texture, monotonous flavor, and poor preservation. Fermentation technology is an effective means of enhancing the nutrition and flavor of fruits and vegetables. Through microbial fermentation, large-molecule nutrients in jujubes can be converted into smaller molecules, improving their absorption rate and producing a unique fermented aroma. However, existing fermented jujube products are mostly single-product preparations, such as fermented jujube juice or fermented jujube paste. There is currently no technology for the simultaneous production of two or more fermented jujube products. Furthermore, the fermentation strains used are mostly conventional commercial strains, which lack compatibility with the jujube substrate, resulting in low nutrient conversion efficiency. In addition, traditional fermentation processes suffer from insufficient enzymatic hydrolysis, single fermentation strains, and poor product stability, limiting the industrial production and market promotion of fermented jujube products.

[0003] Therefore, developing a co-production technology that is rational in process, has high resource utilization, and can simultaneously produce high-quality fermented jujube fruit pulp and fruit puree has important practical significance and application value. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a method for the co-production of fermented jujube fruit pulp. This method is suitable for the simultaneous industrial production of fruit-sucking gel foods and fruit pulp viscous foods, solving the problems of single jujube processing products, low resource utilization, and imperfect fermentation process in the past. It realizes the efficient utilization of jujube resources and simultaneously obtains two fermented jujube products with unique flavors, rich nutrition, and good stability, which are characterized by low sugar, high fiber, and rich probiotics.

[0005] To achieve the above objectives, the technical solution designed by the present invention is as follows: This invention provides a method for the co-production of fermented jujube fruit pulp, comprising the following steps: (1) Raw material pretreatment: Select fresh red dates, remove impurities, wash them several times with warm water, and dry them until the moisture content is 25-30%. (2) Graded crushing: The pre-treated jujubes are graded and crushed by a two-stage crusher to obtain jujube fragments; (3) Segmented fermentation: Add water to the jujube pieces and stir well at 30-35℃ to obtain a mixed liquid. Add a compound fermentation agent to the mixed liquid, and first carry out anaerobic fermentation, then aerobic fermentation to obtain a fermented liquid. The compound fermentation agent is composed of *Lactobacillus plantarum* CICC 20265, *Saccharomyces cerevisiae* CICC 1308, and *Acetobacter* CICC 7010, and the amount of compound fermentation agent added is 0.3-0.5% of the weight of the mixed liquid. (4) Centrifugal separation: The fermentation liquid was centrifuged to obtain the supernatant (fruit absorbent base material) and the precipitate (fruit puree base material). The precipitate was ground into a particle size of ≤100μm by a colloid mill to obtain the crude fermented jujube puree. (5) Differentiated allocation of dual products: a. Fermented red dates and fruit juice blend: Add 8-12% erythritol, 0.1-0.2% citric acid, 0.4-0.6% compound gelling agent, and 0.05-0.1% vitamin C by weight to the supernatant. Stir well and continue stirring. During stirring, raise the temperature from room temperature to 60-70℃ and cook for 15-20 minutes (stirring speed 300-400 r / min). Filter through a screen, cool to 45-55℃ and gel for 20-30 minutes to obtain fermented jujube fruit base liquid. In the compound gelling agent, the weight ratio of konjac gum and carrageenan is 1:2. b. Preparation of fermented jujube puree: Add 5-8% by weight of erythritol, 0.5-1.0% by weight of pectin, 0.2-0.3% by weight of konjac gum, and 0.05-0.1% by weight of vitamin C to the crude fermented jujube puree. After stirring evenly, homogenize it at a pressure of 20-25 MPa and a temperature of 60-65℃ to obtain the base liquid of fermented jujube puree. (6) Sterilization and packaging: The fruit absorbent base liquid and the fruit pulp base liquid were subjected to compound sterilization treatment, aseptic filling and irradiation sterilization treatment respectively to obtain fermented jujube fruit absorbent and fermented jujube fruit pulp.

[0006] Further, in step (1), the fresh red dates are selected from red dates with a maturity of ≥85%, soluble solids ≥18°Brix, and dietary fiber ≥6g / 100g; The water temperature should be 30-40℃, and the washing should be repeated 2-3 times. The drying temperature is 60-70℃.

[0007] Furthermore, in step (2), the primary crushing is carried out to a particle size of 10-15 mm, and the secondary crushing is carried out to a particle size of 2-5 mm.

[0008] Furthermore, in step (3), the water is deionized water, and the amount of deionized water used is 1.5-2.0 times the weight of the jujube pieces; The anaerobic fermentation temperature is 30-32℃, and the anaerobic fermentation time is 24-36h; The aerobic fermentation temperature is 28-30℃, and the aerobic fermentation time is 12-18h; Throughout the fermentation process, the pH of the mixed liquid should be controlled between 3.8 and 4.2.

[0009] Furthermore, in the compound fermentation agent, the viable count of *Lactobacillus plantarum* CICC 20265 is ≥1.0 × 10¹. 0 CFU / g, viable count of Saccharomyces cerevisiae CICC 1308 ≥ 1.0 × 10⁻⁶ 9 CFU / g, viable count of Acetobacter spp. CICC 7010 ≥1.0×10⁻⁶ 8 CFU / g.

[0010] The mass ratio of Lactobacillus plantarum CICC 20265, Saccharomyces cerevisiae CICC 1308, and Acetobacter spp. CICC 7010 was 2:1:1. Among the above-mentioned compound fermentation agents, *Lactobacillus plantarum* (… Lactiplantibacillus plantarum CICC20265 was purchased from the China Industrial Microbial Culture Collection Center, whose website is https: / / www.china-cicc.org / cicc / detail2 / ?sid=2411; brewing yeast ( Saccharomyces cerevisiae CICC 1308 was purchased from the China Industrial Microbial Culture Collection Center, whose website is https: / / www.china-cicc.org / cicc / detail2 / ?sid=1338; Acetobacter spp. ( Acetobacter sp. CICC 7010 was purchased from the China Industrial Microbial Culture Collection Center, whose website is https: / / www.china-cicc.org / cicc / detail2 / ?sid=13357.

[0011] The above-mentioned compound fermentation agent is prepared by encapsulating Bacillus plantarum CICC 20265, Saccharomyces cerevisiae CICC 1308, and Acetobacter spp. CICC 7010 in three layers with an encapsulating agent. The mass ratio of maltodextrin, gum arabic, and chitosan in the encapsulating agent is 3:2:1.

[0012] The above-mentioned compound fermentation agent has a viable bacteria retention rate of ≥80% under pasteurization conditions of 70℃ and 20min.

[0013] Furthermore, in step (4), the centrifugation speed is 4000-5000 r / min, the centrifugation time is 15-20 min, the clarity of the supernatant is ≥95%, and the fiber retention rate of the precipitate is ≥98%.

[0014] Furthermore, in step (5), the stirring speed is 300-400 r / min and the mesh size of the filter screen is 300 mesh; In step b of step (5), the stirring speed is 300-400 r / min. The homogenization pressure was 22-24 MPa, the temperature was 62-65℃, and the homogenization was performed twice.

[0015] Furthermore, in step (5), the cooking temperature is 62-68℃, the stirring speed is 350-380r / min, and the cooking time is 16-18min.

[0016] The above-mentioned fermented jujube fruit extract and fermented jujube fruit puree have a solubility rate of ≥99%, no visible lumps, and a light transmittance of ≥90% after gelation.

[0017] Furthermore, in step (6), the specific steps of compound sterilization are to pasteurize the fruit absorbent liquid or fruit pulp liquid at a temperature of 65-70℃ for 15-20 minutes, then perform ultra-high temperature instantaneous sterilization at a temperature of 135-140℃ for 3-5 seconds, and then quickly cool it to 25-30℃ after sterilization. The specific steps of irradiation sterilization are to irradiate the fruit-based liquid filling product or the fruit puree-based liquid filling product with cobalt-60 γ rays to obtain fermented jujube fruit-based product and fermented jujube fruit puree product, respectively; wherein, the irradiation dose is 2-3kGy, and the product temperature is controlled ≤35℃ during the irradiation process.

[0018] Furthermore, the fermented jujube fruit extract is a transparent gel with an elasticity ≥50g / cm². The fermented jujube fruit extract contains 3.5-4.0g / 100g of dietary fiber, 45-50mg / 100g of vitamin C, 240-260kJ / 100g of energy, has a pH of 3.5-4.0, and contains ≥1×10⁻⁶ viable bacteria of *Lactobacillus plantarum* CICC 20265. 6 CFU / g, total microbial count ≤10CFU / g, no pathogenic bacteria detected, shelf life at room temperature (25℃) ≥12 months, shelf life at frozen (-18℃) ≥24 months; The fermented jujube puree has a fine and viscous texture with a viscosity of 5000-8000 mPa. The fermented jujube puree (at 25℃) contains 4.5-5.0g / 100g of dietary fiber, 50-55mg / 100g of vitamin C, 260-280kJ / 100g of energy, and has a viable count of ≥1×10⁻⁶ *Lactobacillus plantarum* CICC 20265. 6 CFU / g, total microbial count ≤10CFU / g, no pathogenic bacteria detected, shelf life at room temperature (25℃) ≥12 months, shelf life at frozen (-18℃) ≥24 months.

[0019] After irradiation sterilization, the vitamin C retention rate in fermented jujube fruit extract and fermented jujube pulp was ≥85%, the survival rate of Lactobacillus plantarum CICC 20265 was ≥70%, the sensory scores (color, flavor, and taste) decreased by ≤3 points compared with those before irradiation, and no irradiation off-odor was produced.

[0020] This invention addresses the core pain points of the existing jujube processing industry through multi-dimensional technological innovation, achieving the following significant beneficial effects: 1. Maximize resource utilization to achieve green and low-carbon production. The innovative "segmented fermentation-precision centrifugal separation" co-production process simultaneously transforms jujube raw materials into two products: fruit juice and fruit puree. This increases raw material utilization from 60-70% in traditional single-product production to 100%, with zero waste discharge, effectively solving the industry problem of jujube residue waste during processing. The high efficiency and cost-saving characteristics of this co-production model are specifically reflected in: a 30-35% reduction in raw material consumption per unit product; a 25-30% reduction in equipment energy consumption compared to producing both products separately; a reduction in production cycle from 120 hours to 96-102 hours (a 15-20% reduction); a 100% reduction in solid waste treatment costs; and a 20-25% decrease in overall production costs, aligning with the development trend of green food processing.

[0021] 2. The strains have strong adaptability, resulting in significant nutrient conversion and flavor enhancement. The compound fermentation agent is made from Lactobacillus plantarum CICC 20265, Saccharomyces cerevisiae CICC 1308, and Acetobacter spp. CICC7010, which are encapsulated in three layers with an encapsulating agent. The conversion efficiency of nutrients such as polysaccharides and flavonoids is more than 30% higher than that of conventional commercial strains, resulting in a significant increase in the content of absorbable small molecule nutrients in the product. At the same time, it produces a unique jujube-scented fermentation flavor without any off-flavors. The sensory score is 15-20 points higher than that of products fermented with conventional strains, and the product flavor is more distinctive.

[0022] 3. Product quality has been comprehensively upgraded, with significant improvements in sensory appeal and stability. Fruit absorbent products: They use a konjac gum-carrageenan (1:2) compound gelling system, which synergistically leverages the high elasticity of konjac gum and the thermal stability of carrageenan, resulting in fruit absorbent elasticity ≥50g / cm², which is more than 30% higher than that of single gelling agent products; and they also exhibit unexpected stability effects, with no cracking, water separation, or shrinkage after 3 freeze-thaw cycles, solving the defects of insufficient elasticity and poor low-temperature stability of traditional fruit absorbent products; Fruit puree products: Through a two-stage process of "colloid milling + 20-25MPa high-pressure homogenization", combined with a pectin-konjac gum compound stabilization system, the fruit puree particle size is ≤100μm (the lowest in the example is 80μm), the fineness score is ≥95 points, and there is no layering or sedimentation after standing for 30 days. The smoothness of the taste is 40% higher than that of traditional fruit puree, solving the problems of rough texture and easy layering of existing fruit puree. 4. Nutrient retention rate exceeds expectations, with outstanding health benefits. Both products retain the natural color and flavor of jujubes, with a vitamin C content of 45-55mg / 100g and a dietary fiber content of 3.5-5.0g / 100g. The nutrient retention rate is 15-20% higher than that of traditional processes. Erythritol is used instead of traditional sucrose, resulting in an energy content of 240-280kJ / 100g, only 60-70% of that of sucrose-flavored products. Furthermore, erythritol does not participate in blood sugar metabolism and does not cause tooth decay, making it suitable for people controlling their blood sugar, children, and the elderly. The compound fermentation agent undergoes triple encapsulation treatment, resulting in a viable bacteria retention rate of ≥80% after pasteurization. The finished product contains ≥1×10⁻⁶ viable bacteria of *Lactobacillus plantarum* CICC 20265. 6 CFU / g can regulate the balance of intestinal flora and achieve functional upgrades for the product.

[0023] 5. Synergistic optimization of sterilization and preservation extends shelf life and ensures safety. The innovative "low-temperature pasteurization + ultra-high temperature instantaneous sterilization + low-dose irradiation sterilization" composite sterilization system ensures product safety while achieving a shelf life of ≥12 months at room temperature and ≥24 months when frozen, which is more than 50% better than traditional single sterilization processes. Moreover, the irradiation process controls the product temperature to ≤35℃, and there is no irradiation odor, which takes into account both long-term freshness and nutrient retention.

[0024] 6. High degree of process standardization, suitable for large-scale industrial production. The quantitative parameters of each key process are clearly defined, the process fluctuation range is small, the product batch stability is strong, and the pass rate is ≥98%. All the equipment used are conventional equipment in the food industry, and no special customized equipment is required. The modification difficulty is low and the investment cost is small. It can be directly connected to the production line of existing jujube processing enterprises and is suitable for industrial application. Attached Figure Description

[0025] Figure 1This is a schematic diagram of the fermented jujube fruit extract product prepared by the method in Example 1; Figure 2 This is a schematic diagram of the fermented jujube puree product prepared by the method in Example 1. Detailed Implementation

[0026] The present invention will now be described in further detail with reference to specific embodiments, so that those skilled in the art can understand it.

[0027] Example 1 A method for co-producing fermented jujube fruit pulp includes the following steps: (1) Raw material pretreatment: Select 50kg of fresh jujubes (88% maturity, 19°Brix soluble solids, 6.8g / 100g dietary fiber), wash them three times with 35℃ warm water, and dry them with hot air at 65℃ until the moisture content is 28%, to obtain 38kg of dried jujube raw material; (2) Graded crushing: The pre-treated jujubes are crushed in two stages: the first stage crushes them to a particle size of 12mm and the second stage crushes them to a particle size of 3mm to obtain jujube fragments. (3) Segmented fermentation: Add 76 kg of deionized water (twice the weight of the jujube pieces) to the jujube pieces, stir well at 32°C, and adjust the pH to 5.0 with citric acid to obtain a well-mixed liquid. Add 570g of a three-layer embedded compound fermentation agent (0.5% of the weight of the mixed liquid) to the mixed liquid. The compound fermentation agent is *Lactobacillus plantarum* CICC 20265 (live count 1.2 × 10¹). 0 CFU / g), Saccharomyces cerevisiae CICC 1308 (live count 1.1×10⁻⁶) 9 CFU / g), Acetobacter spp. CICC 7010 (viable count 1.3 × 10⁻⁶) 8 The mixture (CFU / g) was prepared by mixing maltodextrin, gum arabic, and chitosan in a mass ratio of 2:1:1 and then encapsulating them in three layers using a maltodextrin: gum arabic: chitosan ratio of 3:2:1 as the encapsulating agent. The mixed solution was placed in a fermenter and first anaerobically fermented at 31°C for 30 hours, followed by aerobic fermentation at 29°C for 15 hours. The final pH of the fermentation was 4.0. Throughout the fermentation process, the pH of the mixed solution was controlled between 3.8 and 4.2 to obtain the fermented solution. Among the above-mentioned compound fermentation agents, *Lactobacillus plantarum* (… Lactiplantibacillus plantarum CICC20265 was purchased from the China Industrial Microbial Culture Collection Center, whose website is https: / / www.china-cicc.org / cicc / detail2 / ?sid=2411; brewing yeast ( Saccharomyces cerevisiae CICC 1308 was purchased from the China Industrial Microbial Culture Collection Center, whose website is https: / / www.china-cicc.org / cicc / detail2 / ?sid=1338. Acetobacter spp. ( Acetobacter sp. CICC 7010 was purchased from the China Industrial Microbial Culture Collection Center, whose website is https: / / www.china-cicc.org / cicc / detail2 / ?sid=13357.

[0028] (4) Centrifugal separation: A disc centrifuge was used to centrifuge at 4500 r / min for 18 min, collecting 87 kg of supernatant and 26 kg of precipitate. The clarity of the supernatant was ≥95%, and the fiber retention rate of the precipitate was ≥98%. The precipitate was ground to a particle size of 80 μm (≤100 μm) using a colloid mill to obtain crude fermented jujube pulp. (5) Differentiated allocation of dual products: a. Fermented red dates and fruit juice blend: Add 8.7 kg of erythritol, 0.13 kg of citric acid, 0.43 kg of compound gelling agent, and 0.06 kg of vitamin C to the supernatant. After stirring evenly, continue stirring at 350 r / min. During stirring, raise the temperature from room temperature to 65℃ and keep it at that temperature for 18 min. Filter through a 300-mesh filter, cool to 50℃ and keep it at that temperature for 25 min to gel, obtaining 96.3 kg of fermented jujube fruit extract. The weight ratio of konjac gum and carrageenan in the compound gelling agent is 1:2. b. Preparation of fermented jujube puree: Add 1.56 kg of erythritol, 0.2 kg of pectin, 0.06 kg of konjac gum, and 0.02 kg of vitamin C to the fermented jujube puree. After stirring evenly, homogenize twice at a pressure of 22 MPa and a temperature of 65℃ to obtain 27.78 kg of fermented jujube puree base liquid.

[0029] (6) Sterilization and packaging: The fruit-based liquid and fruit-based liquid were subjected to a compound sterilization treatment: first, pasteurization at 68℃ for 18 minutes, followed by ultra-high temperature instantaneous sterilization at 138℃ for 4 seconds. After sterilization, the liquid was rapidly cooled to 28℃ and aseptically filled. After filling, cobalt-60 gamma rays were used for irradiation sterilization at a dose of 2.5 kGy. During the irradiation process, the product temperature was controlled to be ≤35℃, resulting in fermented jujube fruit-based liquid product 1 and fermented jujube fruit-based liquid product 1, respectively.

[0030] Example 2 In this embodiment, the steps of raw material pretreatment, grading and crushing, segmented fermentation, centrifugation, fruit puree preparation, sterilization and packaging are the same as in Example 1, except that the fruit puree preparation step is adjusted as follows: (5) Differentiated allocation of dual products: a. Fermented red dates and fruit juice blend: Add 8.7 kg erythritol, 0.13 kg citric acid, 0.478 kg compound gelling agent (konjac gum: carrageenan = 1:2), and 0.06 kg vitamin C to the clear liquid. Stir evenly at 380 r / min, then heat to 67℃ and cook for 16 min. Filter through a 300 mesh filter, cool to 52℃ and gel for 22 min to obtain fermented jujube fruit base liquid.

[0031] Example 3 In this embodiment, the steps of raw material pretreatment, grading and crushing, segmented fermentation, centrifugation, fruit puree preparation, sterilization and packaging are the same as in Example 1. The fruit juice preparation and fruit puree preparation steps are adjusted as follows: (5) Differentiated allocation of dual products: a. Preparation of fermented jujube fruit extract: Add 9.57 kg of erythritol to the supernatant, and the remaining auxiliary materials and process parameters are the same as in Example 1 to obtain the fermented jujube fruit extract base liquid.

[0032] b. Preparation of fermented jujube puree: Add 1.82 kg of erythritol to the crude fermented jujube puree. The remaining auxiliary materials are the same as in Example 1. The homogenization parameters are adjusted to 24 MPa and 63 °C. Homogenize twice to obtain the base liquid of fermented jujube puree.

[0033] Example 4 In this embodiment, the raw material pretreatment and grading crushing steps are the same as in Example 1 in the method for preparing fermented jujube fruit extract product 4 and fermented jujube fruit puree product 4. The segmented fermentation and subsequent steps are adjusted as follows: (3) Segmented fermentation: Add 57 kg of deionized water (1.5 times the weight of the jujube pieces) to the jujube pieces and stir evenly at 35°C to obtain a homogeneous liquid. Add 0.3% (by weight of the homogeneous liquid) of a compound fermentation agent to the homogeneous liquid; the composition of the compound fermentation agent is the same as in Example 1. Place the homogeneous liquid in a fermentation tank and first perform anaerobic fermentation at 30°C for 36 hours, followed by aerobic fermentation at 28°C for 18 hours. The final pH of the fermentation is 4.2. Throughout the fermentation process, the pH of the homogeneous liquid is controlled between 3.8 and 4.2 to obtain the fermented liquid.

[0034] (4) Centrifugation: A disc centrifuge was used to centrifuge at 5000 r / min for 15 min. The supernatant and precipitate were collected. The precipitate was ground in a colloid mill until the particle size was ≤100 μm to obtain the crude fermented jujube pulp.

[0035] (5) Differentiated allocation of dual products: a. Preparation of fermented jujube fruit extract: Add 12% erythritol, 0.2% citric acid, 0.6% compound gelling agent (konjac gum: carrageenan = 1:2), and 0.1% vitamin C to the supernatant. Stir evenly and stir at 400 r / min. Heat to 70℃ and keep warm for 15 min. Filter through a 300-mesh filter and cool to 55℃ and keep warm for 20 min to gel, thus obtaining the fermented jujube fruit extract base liquid.

[0036] b. Preparation of fermented jujube puree: Add 8% by weight of erythritol, 1.0% by weight of pectin, 0.3% by weight of konjac gum and 0.1% by weight of crude fermented jujube puree to the mixture. After stirring evenly, homogenize twice at a pressure of 25 MPa and a temperature of 60°C to obtain fermented jujube puree base liquid.

[0037] (6) Sterilization and Packaging: The fruit-based liquid and fruit-based liquid were subjected to compound sterilization treatment: first, pasteurization at 70℃ for 15 min, then ultra-high temperature instantaneous sterilization at 135℃ for 5 s, and then rapidly cooled to 25℃ for aseptic filling. After filling, cobalt-60 γ-rays were used for irradiation sterilization at a dose of 3 kGy. During the irradiation process, the product temperature was controlled to be ≤35℃, resulting in fermented jujube fruit-based liquid product 4 and fermented jujube fruit-based liquid product 4.

[0038] Example 5 In this embodiment, the centrifugal separation, differentiated blending of the two products, sterilization, and packaging steps in preparing fermented jujube fruit extract product 5 and fermented jujube fruit puree product 5 are consistent with those in Example 1. Adjustments were made to the raw material pretreatment, grading and crushing, and segmented fermentation: (1) Raw material pretreatment: Select 50kg of fresh jujubes (90% maturity, 20°Brix soluble solids, 7.2g / 100g dietary fiber), wash twice with 30℃ warm water, and dry with 60℃ hot air to 25% moisture content to obtain dried jujube raw materials.

[0039] (2) Graded crushing: The pre-treated jujubes are graded and crushed by a two-stage crusher. The first stage crushes the jujubes to a particle size of 10 mm, and the second stage crushes them to a particle size of 2 mm to obtain jujube fragments.

[0040] (3) Segmented fermentation: Add deionized water (1.8 times the weight of the jujube pieces) to the jujube pieces and stir evenly at 30°C to obtain a mixed liquid. Add compound fermentation agent (0.4% of the weight of the mixed liquid) to the mixed liquid. The composition of the compound fermentation agent is the same as in Example 1. Place it in a fermentation tank and first anaerobic ferment at 32°C for 24 hours, then aerobic ferment at 30°C for 12 hours. The pH at the end of the fermentation is 3.8. The pH of the mixed liquid is controlled at 3.8-4.2 throughout the fermentation process to obtain the fermented liquid.

[0041] Comparative Example 1 Except for the use of a single carrageenan (0.41 kg) instead of a compound gelling agent in the fruit pulp preparation, the other steps (raw material pretreatment, grading and crushing, segmented fermentation, centrifugation, fruit pulp preparation, sterilization and packaging, and irradiation sterilization) are the same as in Example 1.

[0042] Comparative Example 2 Except for the use of sucrose instead of erythritol in both fruit juice and fruit puree preparation (the amount added is the same as in Example 1), the other steps (raw material pretreatment, grading and crushing, segmented fermentation, centrifugation, gelling agent ratio, sterilization and packaging, and irradiation sterilization) are the same as in Example 1.

[0043] Comparative Example 3 Lactobacillus plantarum ( Lactiplantibacillus plantarum CICC20265 was used without encapsulation; only fruit-based products were prepared, and the precipitate was discarded directly (raw material utilization rate was about 70%); the fruit puree was not subjected to high-pressure homogenization (only ground to 150μm with a colloid mill); the remaining steps (raw material pretreatment, grading and crushing, fermentation conditions, centrifugation parameters, gelling agent ratio, sterilization and packaging, irradiation sterilization) were consistent with those in Example 1.

[0044] Comparative Example 4 Lactobacillus plantarum ( Lactiplantibacillus plantarum CICC20265, the remaining steps (raw material pretreatment, grading and crushing, fermentation conditions, centrifugation, dual product blending, sterilization and packaging, irradiation sterilization) are the same as in Example 1.

[0045] The performance of the fermented jujube fruit extract and fermented jujube puree products prepared in the above embodiments and comparative examples was tested. 1. The method for detecting fruit-absorbing samples is as follows: a. Elasticity was measured using a TA-XT2i texture analyzer and determined by the compressibility test method of texture profile analysis (TPA); b. The viable count of *Lactobacillus plantarum* CICC 20265 was determined by plate counting method, in accordance with GB4789.35 "Food Microbiology Examination - Lactic Acid Bacteria Examination"; the total microbial count (colon total count) was determined in accordance with GB4789.2 "Food Microbiology Examination - Determination of Total Colony Count".

[0046] c. Sensory evaluation adopts a 100-point comprehensive evaluation method, referring to GB / T16860, and scores are given from four dimensions: color (25 points), texture (25 points), taste (30 points), and flavor (20 points). The average score of 10 professional evaluators is taken.

[0047] d. Dietary fiber content is determined according to GB5009.88 "Determination of Dietary Fiber in Food"; e. Vitamin C content was determined by high performance liquid chromatography, referring to GB5009.86 "Determination of ascorbic acid in food"; f. Energy values ​​are calculated according to the formula specified in GB28050 "General Rules for Nutrition Labelling of Prepackaged Foods".

[0048] h. The shelf life at room temperature (25℃) and frozen (-18℃) is evaluated by a combination of sample retention observation and accelerated stability testing. Sensory, microbiological and physicochemical indicators of the samples are tested regularly. The 90-day stability under refrigeration is assessed by visually observing whether the samples show changes in tissue state such as water separation and shrinkage after static storage at 4℃.

[0049] i. The flavonoid conversion efficiency was determined by high-performance liquid chromatography (HPLC) to measure the flavonoid content before and after conversion, using the following formula: Conversion efficiency (%) = (flavonoid content after conversion / flavonoid content of substrate) × 100%.

[0050] 2. The testing method for fruit puree samples is as follows: a. Viscosity was measured using an NDJ series rotational viscometer; b. The fineness score adopts a 100-point sensory evaluation method, focusing on evaluating the particle texture and uniformity of the sample, in accordance with GB / T16860; the stability after 30 days of standing is determined by visually observing whether the sample shows stratification, water separation and precipitation after standing at room temperature; the particle size is determined by laser particle size analyzer.

[0051] c. The detection methods for viable count, total microbial count, dietary fiber, vitamin C, energy, shelf life at room temperature / frozen, and flavonoid conversion efficiency of *Lactobacillus plantarum* CICC20265 were consistent with those for fruit samples.

[0052] Table 1 Comparison of Fruit Absorption Performance Test Results Table 2 Comparison of Fruit Puree Performance Test Results The test results are analyzed as shown in Tables 1 and 2: 1. Advantages of Co-production Technology: Examples 1-5 utilize a "segmented fermentation-precision centrifugal separation" co-production technology to achieve 100% utilization of jujube raw materials with no waste discharge. Compared to Comparative Example 3 (single product production, raw material utilization rate 70%), this completely solves the industry pain point of waste in jujube processing. In terms of production efficiency, the examples reduce raw material consumption per unit product by 32%, equipment energy consumption by 27%, and the production cycle is reduced from 120 hours in the traditional process to 96-102 hours (a reduction of 18%). Solid waste treatment costs are reduced to zero, and overall production costs decrease by 20-25%. Even though Comparative Example 4 uses a co-production process, the lack of core innovations such as compound microbial strains still cannot compensate for the gap in nutrient conversion and flavor. This further proves the necessity of co-production technology in conjunction with other innovative technologies, and its high efficiency and cost-saving characteristics are fully adapted to the needs of industrial green production.

[0053] 2. Advantages of Compound Fermentation Agents: Examples 1-5 utilize compound fermentation agents, achieving a conversion efficiency of 65-71% for nutrients such as flavonoids in the jujube matrix. This is over 30% higher than Comparative Example 3 (conventional strain + single product, conversion efficiency 40-41%) and Comparative Example 4 (conventional single strain + co-production, conversion efficiency 42-43%), significantly increasing the content of absorbable small-molecule nutrients in the product. In terms of flavor, the sensory scores of the examples reached 88-94 points, an increase of 8-16 points compared to Comparative Example 3 (78 points) and Comparative Example 4 (82 points). The unique jujube aroma and fermented flavor are free of off-flavors, resulting in higher product recognition. This confirms the irreplaceable role of compound fermentation agents in nutrient retention and flavor optimization.

[0054] 3. Effect of the compound gelling system: Examples 1-5 use a compound gelling system of konjac gum and carrageenan (1:2), with an elasticity of 51-58 g / cm², which is 34-53% higher than Comparative Example 1 (carrageenan alone, elasticity 38 g / cm²). Moreover, there is no water separation or shrinkage after 90 days of refrigeration, and the product still maintains its integrity after 3 freeze-thaw cycles, which solves the defects of insufficient elasticity and easy water separation at low temperature of traditional fruit gelling agents. In contrast, Comparative Example 1, due to the lack of synergistic effect of a single gelling agent, has a shelf life of only 8 months at room temperature, which is 33% shorter than that of the examples. Regarding the fruit puree product, the example used a two-stage treatment of "colloid milling + 22-25MPa high-pressure homogenization" combined with a pectin-konjac gum compound stabilization system, resulting in a particle size as low as 75-83μm and a fineness score of 92-97. After standing for 30 days, there was no stratification or sedimentation. In contrast, Comparative Example 3 only underwent colloid milling (particle size 150μm), with a fineness score of only 65 and severe stratification. Comparative Example 4, although using a combined production process, did not optimize the homogenization and stabilization system, resulting in a particle size of 110μm and a fineness score of 88, but still exhibited slight stratification. This fully demonstrates the core role of the two-stage treatment and the compound stabilization system in the fineness and stability of the fruit puree.

[0055] 4. Sugar Substitute and Probiotic Protection Technology: Regarding sugar substitute application, Examples 1-5 use erythritol to replace sucrose. The product energy is controlled at 250-280 kJ / 100g, only 62-73% of Comparative Example 2 (sucrose flavoring, energy 385-402 kJ / 100g), and the sweetness is equivalent to 60-70% of sucrose, without masking the flavonoid and polyphenol flavor of the jujube itself, making it suitable for people controlling their blood sugar, children, and the health needs of middle-aged and elderly people. Regarding probiotic protection, the examples utilize a three-layer encapsulation technology of maltodextrin-ginger-chitosan (3:2:1) to achieve a viable count of 9.2 × 10⁻⁶ *Lactobacillus plantarum* CICC 20265 in the fruit juice and pulp. 6 -1.3×10 7 CFU / g; while Comparative Example 3, which did not undergo encapsulation treatment, had a viable bacterial count of only 6.2 × 10⁻⁶. 4 -8.5×10 4 With a CFU / g and a survival rate of less than 10%, the three-layer encapsulation technology effectively constructs a heat-resistant protective barrier, ensuring a high retention rate of probiotics after sterilization and achieving product functional upgrades.

[0056] 5. Optimization of the Composite Sterilization System: Examples 1-5 employ a composite process of "low-temperature pasteurization + ultra-high-temperature instantaneous sterilization + low-dose irradiation." This achieves a shelf life of 12 months at room temperature and 24 months frozen, while controlling the total microbial count to ≤10 CFU / g and eliminating the detection of pathogenic bacteria. This represents a 100-118% improvement over Comparative Example 3 (6 months at room temperature and 11 months frozen). Furthermore, the irradiation process controls the product temperature to ≤35℃, eliminating any irradiation odor. Although the comparative example partially meets the microbial control standards, its single sterilization process results in significant shortcomings in shelf life and nutrient retention rate.

[0057] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the present invention. Without departing from the technical principles of the present invention, appropriate adjustments can be made to the process parameters, such as enzymatic hydrolysis temperature, fermentation time, and ingredient ratios; these adjustments all fall within the scope of protection of the present invention.

Claims

1. A method for the co-production of fermented jujube fruit pulp, characterized in that: Includes the following steps: (1) Raw material pretreatment: Select fresh red dates, remove impurities, wash them several times with warm water, and dry them until the moisture content is 25-30%. (2) Graded crushing: The pre-treated jujubes are graded and crushed by a two-stage crusher to obtain jujube fragments; (3) Segmented fermentation: Add water to the jujube pieces and stir well at 30-35℃ to obtain a mixed liquid. Add a compound fermentation agent to the mixed liquid, and first carry out anaerobic fermentation, then aerobic fermentation to obtain a fermented liquid. The compound fermentation agent is composed of *Lactobacillus plantarum* CICC 20265, *Saccharomyces cerevisiae* CICC 1308, and *Acetobacter* CICC 7010, and the amount of compound fermentation agent added is 0.3-0.5% of the weight of the mixed liquid. (4) Centrifugal separation: The fermentation liquid was centrifuged to obtain supernatant and precipitate. The precipitate was ground in a colloid mill to a particle size of ≤100μm to obtain crude fermented jujube pulp. (5) Differentiated allocation of dual products: a. Fermented red dates and fruit juice blend: Add 8-12% erythritol, 0.1-0.2% citric acid, 0.4-0.6% compound gelling agent, and 0.05-0.1% vitamin C by weight to the supernatant. Stir well and continue stirring. During stirring, raise the temperature from room temperature to 60-70℃ and simmer for 15-20 minutes. Filter through a screen, cool to 45-55℃ and gel for 20-30 minutes to obtain fermented jujube fruit base liquid. In the compound gelling agent, the weight ratio of konjac gum and carrageenan is 1:

2. b. Preparation of fermented jujube puree: Add 5-8% by weight of erythritol, 0.5-1.0% by weight of pectin, 0.2-0.3% by weight of konjac gum, and 0.05-0.1% by weight of vitamin C to the crude fermented jujube puree. After stirring evenly, homogenize it at a pressure of 20-25 MPa and a temperature of 60-65℃ to obtain the base liquid of fermented jujube puree. (6) Sterilization and packaging: The fruit absorbent base liquid and the fruit pulp base liquid were subjected to compound sterilization treatment, aseptic filling and irradiation sterilization treatment respectively to obtain fermented jujube fruit absorbent and fermented jujube fruit pulp.

2. The co-production method according to claim 1, characterized in that: In step (1), the fresh red dates are selected from red dates with a maturity of ≥85%, soluble solids ≥18°Brix, and dietary fiber ≥6g / 100g; The water temperature should be 30-40℃, and the washing should be repeated 2-3 times. The drying temperature is 60-70℃.

3. The co-production method according to claim 1, characterized in that: In step (2), the primary crushing is carried out to a particle size of 10-15 mm, and the secondary crushing is carried out to a particle size of 2-5 mm.

4. The co-production method according to claim 1, characterized in that: In step (3), the water is deionized water, and the amount of deionized water is 1.5-2.0 times the weight of the jujube pieces. The anaerobic fermentation temperature is 30-32℃, and the anaerobic fermentation time is 24-36h; The aerobic fermentation temperature is 28-30℃, and the aerobic fermentation time is 12-18h; Throughout the fermentation process, the pH of the mixed liquid should be controlled between 3.8 and 4.

2.

5. The co-production method according to claim 1, characterized in that: The viable count of *Lactobacillus plantarum* CICC 20265 in the compound fermentation agent is ≥1.0 × 10¹. 0 CFU / g, viable count of Saccharomyces cerevisiae CICC 1308 ≥ 1.0 × 10⁻⁶ 9 CFU / g, viable count of Acetobacter spp. CICC 7010 ≥1.0×10⁻⁶ 8 CFU / g; The mass ratio of Lactobacillus plantarum CICC 20265, Saccharomyces cerevisiae CICC 1308, and Acetobacter spp. CICC 7010 was 2:1:

1.

6. The co-production method according to claim 1, characterized in that: In step (4), the centrifugation speed is 4000-5000 r / min, the centrifugation time is 15-20 min, the clarity of the supernatant is ≥95%, and the fiber retention rate of the precipitate is ≥98%.

7. The co-production method according to claim 1, characterized in that: In step (5), the stirring speed is 300-400 r / min and the filter mesh size is 300 mesh. In step b of step (5), the stirring speed is 300-400 r / min. The homogenization pressure was 22-24 MPa, the temperature was 62-65℃, and the homogenization was performed twice.

8. The co-production method according to claim 1, characterized in that: In step (5), the cooking temperature is 62-68℃, the stirring speed is 350-380r / min, and the cooking time is 16-18min.

9. The co-production method according to claim 1, characterized in that: In step (6), the specific steps of compound sterilization are to pasteurize the fruit absorbent liquid or fruit pulp liquid at a temperature of 65-70℃ for 15-20 minutes, then sterilize it at an ultra-high temperature of 135-140℃ for 3-5 seconds, and then quickly cool it to 25-30℃ after sterilization. The specific steps of irradiation sterilization are to irradiate the fruit-based liquid filling product or the fruit puree-based liquid filling product with cobalt-60 γ rays to obtain fermented jujube fruit-based product and fermented jujube fruit puree product, respectively; wherein, the irradiation dose is 2-3kGy, and the product temperature is controlled ≤35℃ during the irradiation process.

10. The co-production method according to claim 1, characterized in that: The fermented jujube fruit extract is a transparent gel with an elasticity ≥50g / cm². It contains 3.5-4.0g / 100g of dietary fiber, 45-50mg / 100g of vitamin C, 240-260kJ / 100g of energy, a pH of 3.5-4.0, and a viable count of *Lactobacillus plantarum* CICC 20265 ≥1×10⁻⁶. 6 CFU / g, total microbial count ≤10 CFU / g; The viscosity of the fermented jujube puree is 5000-8000 mPa. The fermented jujube puree contains 4.5-5.0 g / 100g of dietary fiber, 50-55 mg / 100g of vitamin C, 260-280 kJ / 100g of energy, and ≥1×10⁻⁶ viable bacteria of *Lactobacillus plantarum* CICC20265. 6 CFU / g, total microbial count ≤10 CFU / g.

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