Composite vegetable gum step-by-step fermented jelly and preparation method thereof

Abstract

The invention provides a compound vegetable gum step-by-step fermented jelly and a preparation method thereof. Comprising the following steps: (1) taking konjaku flour and locust bean gum as raw materials, and preparing a high-elasticity layer by utilizing lactobacillus plantarum fermentation; (2) taking iota-carrageenan, sodium alginate and low-ester pectin as raw materials, and preparing a temperature-sensitive quick-melting layer by utilizing lactobacillus acidophilus and aroma-producing yeast; (3) gradient cooling: carrying out 25 DEG C / 10-15 min to 10 DEG C / 25-30 min to obtain the double-layer jelly; (4) electrostatically spraying a naringin-beta-cyclodextrin embedding substance solution on the surface of the double-layer jelly; and (5) carrying out UV-C irradiation, packaging and refrigerating. According to the invention, a gradient gel network is constructed through step-by-step fermentation of lactic acid bacteria and yeast by using pH and temperature response characteristics of different colloids through a composite vegetable gum step-by-step fermentation technology (konjaku flour-locust bean gum high-elasticity layer fermentation and carrageenan-sodium alginate temperature-sensitive quick-melting layer fermentation), so that the double-layer texture of soft upper part and tough lower part is realized, the upper layer melts in the mouth, and the taste is good. And the lower layer is chewy (similar to the mouth feel of a lava cake).

Description

Technical Field

[0001] This invention relates to the technical field of food processing, specifically to a composite plant gum stepwise fermented jelly and its preparation method. Background Art

[0002] As a popular snack, jelly's traditional production process suffers from numerous technological limitations, urgently requiring innovative breakthroughs. Currently, commercially available jelly products primarily utilize single-colloid compound systems such as carrageenan, konjac gum, or gelatin, combined with numerous food additives (such as citric acid, potassium sorbate, and artificial flavorings) to maintain texture and flavor stability. This traditional process faces several key technological bottlenecks: First, in terms of nutritional value, traditional jelly products have a simple nutritional composition, primarily consisting of water and sugar, lacking functionally active nutrients. Although some products may have added vitamins or minerals, their bioavailability is often low. More significantly, traditional processes completely fail to retain active ingredients such as probiotics; the high-temperature sterilization process inactivates all microorganisms, causing the product to lose its potential gut health regulating function. Second, regarding textural properties, single-colloid systems struggle to balance elasticity and palatability. For example, while carrageenan alone achieves high gel strength, the product is brittle and lacks resilience; conversely, using konjac gum alone results in an overly elastic product lacking a melt-in-your-mouth feel. To balance the texture, manufacturers have had to blend multiple colloids (such as carrageenan, xanthan gum, and locust bean gum), which not only significantly increases raw material costs but may also lead to compatibility issues between the colloids. Furthermore, traditional technologies face a dilemma in terms of preservation: high-temperature sterilization to ensure microbial safety completely inactivates functional components; refrigeration to preserve live bacteria significantly increases cold chain costs and limits shelf life. While some improved technologies have been reported in recent years, these technologies only address single problems and cannot achieve synergistic optimization of texture, nutrition, and flavor. Therefore, developing a healthy, palatable jelly that also enhances product value has broad market prospects. Summary of the Invention

[0003] Technical Problem to be Solved: To address the aforementioned technical problems, the purpose of this invention is to provide a composite plant gum stepwise fermented jelly and its preparation method. This invention utilizes a composite plant gum stepwise fermentation technology (konjac flour-locust bean gum high-elasticity layer fermentation and ι-carrageenan-sodium alginate-low-ester pectin temperature-sensitive quick-melting layer fermentation). Taking advantage of the pH and temperature response characteristics of different colloids, a gradient gel network is constructed through stepwise fermentation by lactic acid bacteria and yeast. Specifically, the high-elasticity layer (pH 4.0): konjac flour and locust bean gum, under the fermentation of *Lactobacillus plantarum*, undergo β-mannanase degradation to produce low-molecular-weight polysaccharides, which synergistically form a three-dimensional network structure with lactic acid. The temperature-sensitive quick-melting layer (pH 5.0-6.0): ι-carrageenan and sodium alginate, under the action of polysaccharides produced by yeast fermentation, form a thermally reversible helical structure. This achieves a "soft on top, chewy on the bottom" double-layer texture; the upper layer melts in the mouth, while the lower layer is chewy (similar to the texture of a "lava cake").

[0004] Technical solution: A composite plant colloid stepwise fermented jelly, the jelly having a pH-sensitive color-changing effect, is formed by stepwise fermentation of composite plant colloids under dual pH / temperature control, forming an upper temperature-sensitive fast-melting layer and a lower highly elastic layer.

[0005] Furthermore, the composite plant gum of the temperature-sensitive quick-melting layer is carrageenan and sodium alginate; the composite plant gum of the high-elasticity layer is konjac powder and locust bean gum.

[0006] The preparation method of the above-mentioned compound plant gum stepwise fermentation jelly includes the following steps: (1) Fermentation and preparation of high elasticity layer: Take 3-6% konjac powder and 1-2% locust bean gum, mix them evenly and disperse them in 80℃ pure water, stir to dissolve for 10 min, cool to 45℃, add 0.5% yeast extract; inoculate with Lactobacillus plantarum, adjust the pH to 4.0 with lactic acid, ferment at 30-35℃ for 9-10 h; quickly cool to 20℃, pour into mold to 45-55% height, let stand for 30 min to form the lower layer; (2) Fermentation and preparation of temperature-sensitive quick-melting layer: Mix 0.5-0.8% 1-carrageenan, 0.3-0.5% sodium alginate, 0.2-0.4% low-ester pectin and 0.08% purple cabbage anthocyanin, and dissolve in 75℃ purified water; cool to 40℃, add 0.05-0.1% KCl, stir at 200-300rpm for 5min, add 2% sucrose, inoculate with Lactobacillus acidophilus and aroma-producing yeast, adjust pH to 5.0-6.0, and ferment at 30-40℃ for 6h; slowly pour into the mold with the solidified lower layer until the mold is full; (3) Gradient cooling: First, keep the temperature at 25℃ for 10-15 minutes to allow the colloid to initially form a network structure, then cool down to 10℃ and keep it for 25-30 minutes to promote complete curing of the colloid and obtain a double-layer jelly. (4) Electrostatically spray a solution of naringin-β-cyclodextrin encapsulation onto the surface of the double-layer jelly; (5) Irradiate with UV-C for 4-5 minutes, then package and refrigerate.

[0007] Furthermore, in step (1), the *Lactobacillus plantarum* is either *Lactobacillus plantarum* 550 or *Lactobacillus plantarum* 360, and the inoculation amount is 1.0 × 10⁻⁶. 7 -2.0×10 7 CFU / mL.

[0008] Furthermore, the inoculum size of Lactobacillus acidophilus in step (2) is 5.0 × 10⁻⁶. 5 -6.0×10 5 CFU / mL; the aroma-producing yeast was Kluyveromyces martensii, and the inoculum size was 1.0 × 10⁻⁶. 7 -2.0×10 7 CFU / mL.

[0009] Furthermore, in step (3), the cooling rate from 25°C to 10°C is 1°C / min.

[0010] Furthermore, the preparation method of the naringin-β-cyclodextrin encapsulating solution in step (4) is as follows: Step 1: Mix β-cyclodextrin and purified water at a mass ratio of 1:10, heat to 50-60℃, and dissolve with ultrasonic assistance; Step 2: Dissolve naringin in a 30-50% ethanol solution, and slowly add it dropwise to a β-cyclodextrin aqueous solution. Maintain the temperature at 50-60℃ and stir continuously at 200-300 rpm for 4-5 hours. Step 3: High-pressure homogenization at 50-60 MPa, repeated 3 times; Step 4: Spray drying was performed to obtain the naringin-β-cyclodextrin encapsulated compound; Step 5: Disperse the naringin-β-cyclodextrin encapsulated compound in a 5% glycerol solution and stir at 100 rpm for 10 min to obtain the final product.

[0011] Furthermore, the molar ratio of β-cyclodextrin in step 1 to naringin in step 2 is 1:1-1.5.

[0012] Furthermore, the parameters for spray drying in step 4 are as follows: inlet air temperature: 170-190℃; outlet air temperature: 80-90℃; atomization pressure: 0.3-0.5MPa; feed rate: 5-10L / min.

[0013] Furthermore, in step 5, the mass ratio of naringin-β-cyclodextrin encapsulation to 5% glycerol solution is (1-3):(97-99).

[0014] Furthermore, in step (4), the voltage of electrostatic spraying is 13-15kV and the flow rate is 1.5-2mL / min.

[0015] Beneficial effects: This invention utilizes a multi-step fermentation technology combining plant gums (konjac flour-sophora bean gum high-elasticity layer fermentation and ι-carrageenan-sodium alginate-low-ester pectin temperature-sensitive quick-melting layer fermentation). Taking advantage of the pH and temperature response characteristics of different colloids, a gradient gel network is constructed through stepwise fermentation by lactic acid bacteria and yeast. The high-elasticity layer (pH 4.0): Konjac flour and sophora bean gum, under the fermentation of *Lactobacillus plantarum*, undergo degradation by β-mannanase to produce low-molecular-weight polysaccharides, which synergistically form a three-dimensional network structure with lactic acid. The temperature-sensitive quick-melting layer (pH 5.0-6.0): ι-carrageenan, sodium alginate, and low-ester pectin, under the action of extracellular polysaccharides produced by yeast fermentation, form a thermally reversible helical structure. This achieves a double-layered texture that is "soft on top and chewy on the bottom," with the upper layer melting in the mouth and the lower layer requiring chewing (similar to the texture of a "lava cake").

[0016] This invention utilizes a composite colloid interpenetrating network technology (fermentation metabolites driving colloid self-assembly) to achieve a dynamic gelation mechanism: lactic acid from the highly elastic layer diffuses to the temperature-sensitive quick-melting layer, triggering localized gelation enhancement of sodium alginate; extracellular polysaccharides from the temperature-sensitive quick-melting layer permeate to the elastic layer, thereby improving the water-holding capacity of konjac flour.

[0017] This invention employs gradient cooling technology and phase transition control in stages: a 25℃ holding stage (10-15 min) allows ι-carrageenan to complete the conformational transition from a random coil to a single helix; a 10℃ holding stage (25-30 min) promotes the formation of a stable network between konjac glucomannan and locust bean gum through hydrogen bonds; and cooling rate control: a linear cooling rate of 1℃ / min ensures that the upper carrageenan fully forms a "weak gel" structure (melting point at 25-30℃), while the lower konjac powder achieves slow dehydration and shrinkage (improved water retention).

[0018] This invention utilizes a probiotic-yeast co-fermentation technology (Lactobacillus plantarum 550 + Kluyveromyces martensii). Lactobacillus plantarum produces acid to form a gel matrix, while simultaneously degrading some konjac flour into oligosaccharides (prebiotics). Sophora japonica gum forms a highly elastic gel under acidic conditions. Yeast metabolism generates flavor esters, resulting in a natural fruity aroma (ethyl acetate).

[0019] This invention utilizes naringin-β-cyclodextrin encapsulation technology to encapsulate hydrophobic bitter molecules (naringin) in a cavity of β-cyclodextrin, increasing the bitterness score from 2.8 to 4.5, improving solubility by 20 times, and achieving a sustained-release effect.

[0020] This invention utilizes pH-responsive colorimetric technology (0.08% purple cabbage anthocyanins), which allows anthocyanins to reversibly change color between pH 4.0 (red) and 5.5 (blue), with a ΔE value of 25.3, thus enhancing the user experience.

[0021] This invention utilizes UV-C cold sterilization technology, where short-wave ultraviolet light destroys microbial DNA. Due to the protection of sodium alginate, the viable bacteria retention rate is ≥90%, extending the shelf life.

[0022] This invention utilizes electrostatic spraying technology to achieve uniform distribution of the embedded material through charge adsorption, thereby improving the survival rate of live bacteria. Detailed Implementation

[0023] This invention proposes a stepwise fermentation jelly using composite plant gum and its preparation method. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the following will provide a more detailed description of the invention with reference to specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0024] Example 1 The preparation method of the naringin-β-cyclodextrin encapsulation solution is as follows: Step 1: Mix 10g of β-cyclodextrin and 100g of purified water, heat to 55℃, and dissolve with ultrasonic assistance; Step 2: Dissolve 5.12g of naringin in 20mL of 40% ethanol aqueous solution, and slowly add it dropwise to β-cyclodextrin aqueous solution. Maintain the temperature at 550℃ and stir continuously at 300rpm for 4h. Step 3: High-pressure homogenization at 55 MPa, repeated 3 times; Step 4: Perform spray drying. The spray drying parameters are: inlet air temperature: 180℃; outlet air temperature: 80℃; atomization pressure: 0.4MPa; feed rate: 8L / min, to obtain naringin-β-cyclodextrin encapsulated compound. Step 5: Disperse 2g of naringin-β-cyclodextrin encapsulation in 98g of 5% glycerol solution and stir at 100rpm for 10min to obtain the final product.

[0025] Example 2 The preparation method of the naringin-β-cyclodextrin encapsulation solution is as follows: Step 1: Mix 10g of β-cyclodextrin and 100g of purified water, heat to 55℃, and dissolve with ultrasonic assistance; Step 2: Dissolve 6.00g of naringin in 20mL of 40% ethanol aqueous solution, and slowly add it dropwise to β-cyclodextrin aqueous solution. Maintain the temperature at 550℃ and stir continuously at 300rpm for 4h. Step 3: High-pressure homogenization at 55 MPa, repeated 3 times; Step 4: Perform spray drying. The spray drying parameters are: inlet air temperature: 180℃; outlet air temperature: 80℃; atomization pressure: 0.4MPa; feed rate: 8L / min, to obtain naringin-β-cyclodextrin encapsulated compound. Step 5: Disperse 2g of naringin-β-cyclodextrin encapsulation in 98g of 5% glycerol solution and stir at 100rpm for 10min to obtain the final product.

[0026] Example 3 The preparation method of the naringin-β-cyclodextrin encapsulation solution is as follows: Step 1: Mix 10g of β-cyclodextrin and 100g of purified water, heat to 55℃, and dissolve with ultrasonic assistance; Step 2: Dissolve 7.68g of naringin in 20mL of 40% ethanol aqueous solution, and slowly add it dropwise to β-cyclodextrin aqueous solution. Maintain the temperature at 550℃ and stir continuously at 300rpm for 4h. Step 3: High-pressure homogenization at 55 MPa, repeated 3 times; Step 4: Perform spray drying. The spray drying parameters are: inlet air temperature: 180℃; outlet air temperature: 80℃; atomization pressure: 0.4MPa; feed rate: 8L / min, to obtain naringin-β-cyclodextrin encapsulated compound. Step 5: Disperse 2g of naringin-β-cyclodextrin encapsulation in 98g of 5% glycerol solution and stir at 100rpm for 10min to obtain the final product.

[0027] Example 4 The preparation method of the naringin-β-cyclodextrin encapsulation solution is as follows: Step 1: Mix 10g of β-cyclodextrin and 100g of purified water, heat to 55℃, and dissolve with ultrasonic assistance; Step 2: Dissolve 6.00g of naringin in 20mL of 40% ethanol aqueous solution, and slowly add it dropwise to β-cyclodextrin aqueous solution. Maintain the temperature at 550℃ and stir continuously at 300rpm for 4h. Step 3: High-pressure homogenization at 55 MPa, repeated 3 times; Step 4: Perform spray drying. The spray drying parameters are: inlet air temperature: 180℃; outlet air temperature: 80℃; atomization pressure: 0.4MPa; feed rate: 5L / min to obtain naringin-β-cyclodextrin encapsulated compound. Step 5: Disperse 2g of naringin-β-cyclodextrin encapsulation in 98g of 5% glycerol solution and stir at 100rpm for 10min to obtain the final product.

[0028] Example 5 The preparation method of the naringin-β-cyclodextrin encapsulation solution is as follows: Step 1: Mix 10g of β-cyclodextrin and 100g of purified water, heat to 55℃, and dissolve with ultrasonic assistance; Step 2: Dissolve 6.00g of naringin in 20mL of 40% ethanol aqueous solution, and slowly add it dropwise to β-cyclodextrin aqueous solution. Maintain the temperature at 550℃ and stir continuously at 300rpm for 4h. Step 3: High-pressure homogenization at 55 MPa, repeated 3 times; Step 4: Perform spray drying. The spray drying parameters are: inlet air temperature: 180℃; outlet air temperature: 80℃; atomization pressure: 0.4MPa; feed rate: 10L / min to obtain naringin-β-cyclodextrin encapsulated material. Step 5: Disperse 2g of naringin-β-cyclodextrin encapsulation in 98g of 5% glycerol solution and stir at 100rpm for 10min to obtain the final product.

[0029] Performance testing: Encapsulation efficiency: determined by HPLC.

[0030] Solubility (water): The embedded material was added to water, magnetically stirred at 25°C for 30 min, and the supernatant was taken after centrifugation to determine the concentration of naringin (HPLC).

[0031] Bitterness masking effect: Sensory evaluation: 10 people were randomly selected from the company for blind testing, with scores ranging from 0 (extremely bitter) to 5 (no bitterness); Test solution: 5% sucrose aqueous solution containing 0.1% of the encapsulated material.

[0032] Storage stability: After 30 days at 40℃ / 75% relative humidity, the decrease in encapsulation rate was measured.

[0033] The results are shown in Table 1 below: Table 1

[0034] Taking into account the performance of each embodiment, the naringin-β-cyclodextrin encapsulation solution prepared in Example 2 was selected for subsequent experiments.

[0035] The *Lactobacillus plantarum* used in the following experiments was *Lactobacillus plantarum* 550, purchased from Sichuan Gaofuji Biotechnology Co., Ltd.; the *Lactobacillus acidophilus* was *Lactobacillus acidophilus* LA05, purchased from Weikang Probiotics (Suzhou) Co., Ltd.; and the aroma-producing yeast was *Kluyveromyces martensii*, purchased from the Microbial Strains Query Network, number: bio-119798.

[0036] Example 6 A method for preparing a composite plant gum stepwise fermented jelly includes the following steps: (1) Fermentation and preparation of the high-elasticity layer: Take 3% konjac powder and 2% locust bean gum, mix them evenly and disperse them in 80℃ pure water, stir to dissolve for 10 min, cool to 45℃, add 0.5% yeast extract; inoculate with 550 Lactobacillus plantarum, with an inoculation amount of 1.0×10 7 CFU / mL, adjust pH to 4.0 with lactic acid, ferment at 35℃ for 9h; rapidly cool to 20℃, pour into molds to 50% height, and let stand for 30min to form the lower layer; (2) Fermentation and preparation of temperature-sensitive rapid-melting layer: Mix 0.7% ι-carrageenan, 0.4% sodium alginate, 0.3% low-ester pectin and 0.08% purple cabbage anthocyanin, and dissolve in purified water at 75℃; cool to 40℃, add 0.08% KCl, stir at 250rpm for 5min, add 2% sucrose, and inoculate with Lactobacillus acidophilus LA05 (inoculation amount is 5.5×10 5 CFU / mL) and Kluyveromyces martensii (inoculation amount of 1.5 × 10⁻⁶ CFU / mL) 7 (CFU / mL), adjust pH to 5.5, ferment at 35℃ for 6 hours; slowly pour into the mold with the solidified lower layer until the mold is full; (3) Gradient cooling: First, keep the temperature at 25℃ for 13 min to allow the colloid to initially form a network structure. Then, cool the temperature to 10℃ and keep it for 28 min. The cooling rate is 1℃ / min to promote the complete solidification of the colloid and obtain a double-layer jelly. (4) Electrostatically spray a naringin-β-cyclodextrin embedding solution onto the surface of the double-layer jelly. The spraying amount is 8 mg solution / kg double-layer jelly. The voltage of electrostatic spraying is 14 kV and the flow rate is 1.8 mL / min. (5) Irradiate with UV-C for 5 minutes at an intensity of 1.6 mW / cm. 2 Packaging and refrigeration.

[0037] Example 7 A method for preparing a composite plant gum stepwise fermented jelly includes the following steps: (1) Fermentation and preparation of the high elasticity layer: Take 5% konjac powder and 1.5% locust bean gum, mix them evenly and disperse them in 80℃ pure water, stir to dissolve for 10 min, cool to 45℃, add 0.5% yeast extract; inoculate with 550 Lactobacillus plantarum, with an inoculation amount of 1.5×10 7 CFU / mL, adjust pH to 4.0 with lactic acid, ferment at 35℃ for 9h; rapidly cool to 20℃, pour into molds to 50% height, and let stand for 30min to form the lower layer; (2) Fermentation and preparation of temperature-sensitive rapid-melting layer: Mix 0.7% ι-carrageenan, 0.4% sodium alginate, 0.3% low-ester pectin and 0.08% purple cabbage anthocyanin, and dissolve in purified water at 75℃; cool to 40℃, add 0.08% KCl, stir at 250rpm for 5min, add 2% sucrose, and inoculate with Lactobacillus acidophilus LA05 (inoculation amount is 5.5×10 5 CFU / mL) and Kluyveromyces martensii (inoculation amount of 1.5 × 10⁻⁶ CFU / mL) 7 (CFU / mL), adjust pH to 5.5, ferment at 35℃ for 6 hours; slowly pour into the mold with the solidified lower layer until the mold is full; (3) Gradient cooling: First, keep the temperature at 25℃ for 13 min to allow the colloid to initially form a network structure. Then, cool the temperature to 10℃ and keep it for 28 min. The cooling rate is 1℃ / min to promote the complete solidification of the colloid and obtain a double-layer jelly. (4) Electrostatically spray a naringin-β-cyclodextrin embedding solution onto the surface of the double-layer jelly. The spraying amount is 8 mg solution / kg double-layer jelly. The voltage of electrostatic spraying is 14 kV and the flow rate is 1.8 mL / min. (5) Irradiate with UV-C for 5 minutes at an intensity of 1.6 mW / cm. 2 Packaging and refrigeration.

[0038] Example 8 A method for preparing a composite plant gum stepwise fermented jelly includes the following steps: (1) Fermentation and preparation of the high-elasticity layer: Take 6% konjac powder and 1% locust bean gum, mix them evenly and disperse them in 80℃ pure water, stir to dissolve for 10 min, cool to 45℃, add 0.5% yeast extract; inoculate with 550 Lactobacillus plantarum, with an inoculation amount of 2.0×10 7 CFU / mL, adjust pH to 4.0 with lactic acid, ferment at 35℃ for 9h; rapidly cool to 20℃, pour into molds to 50% height, and let stand for 30min to form the lower layer; (2) Fermentation and preparation of temperature-sensitive rapid-melting layer: Mix 0.7% ι-carrageenan, 0.4% sodium alginate, 0.3% low-ester pectin and 0.08% purple cabbage anthocyanin, and dissolve in purified water at 75℃; cool to 40℃, add 0.08% KCl, stir at 250rpm for 5min, add 2% sucrose, and inoculate with Lactobacillus acidophilus LA05 (inoculation amount is 5.5×10 5 CFU / mL) and Kluyveromyces martensii (inoculation amount of 1.5 × 10⁻⁶ CFU / mL) 7 (CFU / mL), adjust pH to 5.5, ferment at 35℃ for 6 hours; slowly pour into the mold with the solidified lower layer until the mold is full; (3) Gradient cooling: First, keep the temperature at 25℃ for 13 min to allow the colloid to initially form a network structure. Then, cool the temperature to 10℃ and keep it for 28 min. The cooling rate is 1℃ / min to promote the complete solidification of the colloid and obtain a double-layer jelly. (4) Electrostatically spray a naringin-β-cyclodextrin embedding solution onto the surface of the double-layer jelly. The spraying amount is 8 mg solution / kg double-layer jelly. The voltage of electrostatic spraying is 14 kV and the flow rate is 1.8 mL / min. (5) Irradiate with UV-C for 4 minutes at an intensity of 1.6 mW / cm. 2 Packaging and refrigeration.

[0039] Example 9 A method for preparing a composite plant gum stepwise fermented jelly includes the following steps: (1) Fermentation and preparation of the high elasticity layer: Take 5% konjac powder and 1.5% locust bean gum, mix them evenly and disperse them in 80℃ pure water, stir to dissolve for 10 min, cool to 45℃, add 0.5% yeast extract; inoculate with 550 Lactobacillus plantarum, with an inoculation amount of 1.5×10 7 CFU / mL, adjust pH to 4.0 with lactic acid, ferment at 35℃ for 9h; rapidly cool to 20℃, pour into molds to 50% height, and let stand for 30min to form the lower layer; (2) Fermentation and preparation of temperature-sensitive rapid-melting layer: Mix 0.5% 1-carrageenan, 0.5% sodium alginate, 0.3% low-ester pectin and 0.08% purple cabbage anthocyanin, and dissolve in purified water at 75℃; cool to 40℃, add 0.05% KCl, stir at 250rpm for 5min, add 2% sucrose, and inoculate with Lactobacillus acidophilus LA05 (inoculation amount is 5.5×10⁻⁶). 5 CFU / mL) and Kluyveromyces martensii (inoculation amount of 1.5 × 10⁻⁶ CFU / mL) 7 (CFU / mL), adjust pH to 5.5, ferment at 35℃ for 6 hours; slowly pour into the mold with the solidified lower layer until the mold is full; (3) Gradient cooling: First, keep the temperature at 25℃ for 13 min to allow the colloid to initially form a network structure. Then, cool the temperature to 10℃ and keep it for 28 min. The cooling rate is 1℃ / min to promote the complete solidification of the colloid and obtain a double-layer jelly. (4) Electrostatically spray a naringin-β-cyclodextrin embedding solution onto the surface of the double-layer jelly. The spraying amount is 8 mg solution / kg double-layer jelly. The voltage of electrostatic spraying is 14 kV and the flow rate is 1.8 mL / min. (5) Irradiate with UV-C for 4 minutes at an intensity of 1.6 mW / cm. 2 Packaging and refrigeration.

[0040] Example 10 A method for preparing a composite plant gum stepwise fermented jelly includes the following steps: (1) Fermentation and preparation of the high elasticity layer: Take 5% konjac powder and 1.5% locust bean gum, mix them evenly and disperse them in 80℃ pure water, stir to dissolve for 10 min, cool to 45℃, add 0.5% yeast extract; inoculate with 550 Lactobacillus plantarum, with an inoculation amount of 1.5×10 7 CFU / mL, adjust pH to 4.0 with lactic acid, ferment at 35℃ for 9h; rapidly cool to 20℃, pour into molds to 50% height, and let stand for 30min to form the lower layer; (2) Fermentation and preparation of temperature-sensitive rapid-melting layer: Mix 0.6% ι-carrageenan, 0.4% sodium alginate, 0.3% low-ester pectin and 0.08% purple cabbage anthocyanin, and dissolve in purified water at 75℃; cool to 40℃, add 0.07% KCl, stir at 250rpm for 5min, add 2% sucrose, and inoculate with Lactobacillus acidophilus LA05 (inoculation amount is 5.5×10⁻⁶). 5 CFU / mL) and Kluyveromyces martensii (inoculation amount of 1.5 × 10⁻⁶ CFU / mL) 7 (CFU / mL), adjust pH to 5.5, ferment at 35℃ for 6 hours; slowly pour into the mold with the solidified lower layer until the mold is full; (3) Gradient cooling: First, keep the temperature at 25℃ for 13 min to allow the colloid to initially form a network structure. Then, cool the temperature to 10℃ and keep it for 28 min. The cooling rate is 1℃ / min to promote the complete solidification of the colloid and obtain a double-layer jelly. (4) Electrostatically spray a naringin-β-cyclodextrin embedding solution onto the surface of the double-layer jelly. The spraying amount is 8 mg solution / kg double-layer jelly. The voltage of electrostatic spraying is 14 kV and the flow rate is 1.8 mL / min. (5) Irradiate with UV-C for 4 minutes at an intensity of 1.6 mW / cm. 2 Packaging and refrigeration.

[0041] Example 11 A method for preparing a composite plant gum stepwise fermented jelly includes the following steps: (1) Fermentation and preparation of the high elasticity layer: Take 5% konjac powder and 1.5% locust bean gum, mix them evenly and disperse them in 80℃ pure water, stir to dissolve for 10 min, cool to 45℃, add 0.5% yeast extract; inoculate with 550 Lactobacillus plantarum, with an inoculation amount of 1.5×10 7 CFU / mL, adjust pH to 4.0 with lactic acid, ferment at 35℃ for 9h; rapidly cool to 20℃, pour into molds to 50% height, and let stand for 30min to form the lower layer; (2) Fermentation and preparation of temperature-sensitive rapid-melting layer: Mix 0.8% ι-carrageenan, 0.3% sodium alginate, 0.2% low-ester pectin and 0.08% purple cabbage anthocyanin, and dissolve in purified water at 75℃; cool to 40℃, add 0.05% KCl, stir at 250rpm for 5min, add 2% sucrose, and inoculate with Lactobacillus acidophilus LA05 (inoculation amount is 5.0×10⁻⁶). 5 CFU / mL) and Kluyveromyces martensii (inoculation amount of 2.0 × 10⁻⁶ CFU / mL) 7 (CFU / mL), adjust pH to 5.5, ferment at 35℃ for 6 hours; slowly pour into the mold with the solidified lower layer until the mold is full; (3) Gradient cooling: First, keep the temperature at 25℃ for 13 min to allow the colloid to initially form a network structure. Then, cool the temperature to 10℃ and keep it for 28 min. The cooling rate is 1℃ / min to promote the complete solidification of the colloid and obtain a double-layer jelly. (4) Electrostatically spray a naringin-β-cyclodextrin embedding solution onto the surface of the double-layer jelly. The spraying amount is 8 mg solution / kg double-layer jelly. The voltage of electrostatic spraying is 14 kV and the flow rate is 1.8 mL / min. (5) Irradiate with UV-C for 5 minutes at an intensity of 1.6 mW / cm. 2 Packaging and refrigeration.

[0042] Example 12 A method for preparing a composite plant gum stepwise fermented jelly includes the following steps: (1) Fermentation and preparation of the high elasticity layer: Take 5% konjac powder and 1.5% locust bean gum, mix them evenly and disperse them in 80℃ pure water, stir to dissolve for 10 min, cool to 45℃, add 0.5% yeast extract; inoculate with 550 Lactobacillus plantarum, with an inoculation amount of 1.5×10 7 CFU / mL, adjust pH to 4.0 with lactic acid, ferment at 35℃ for 9h; rapidly cool to 20℃, pour into molds to 50% height, and let stand for 30min to form the lower layer; (2) Fermentation and preparation of temperature-sensitive rapid-melting layer: Mix 0.8% ι-carrageenan, 0.4% sodium alginate, 0.4% low-ester pectin and 0.08% purple cabbage anthocyanin, and dissolve in purified water at 75℃; cool to 40℃, add 0.1% KCl, stir at 250rpm for 5min, add 2% sucrose, and inoculate with Lactobacillus acidophilus LA05 (inoculation amount is 6.0×10⁻⁶). 5 CFU / mL) and Kluyveromyces martensii (inoculation amount of 1.0 × 10⁻⁶ CFU / mL) 7 (CFU / mL), adjust pH to 5.5, ferment at 35℃ for 6 hours; slowly pour into the mold with the solidified lower layer until the mold is full; (3) Gradient cooling: First, keep the temperature at 25℃ for 13 min to allow the colloid to initially form a network structure. Then, cool the temperature to 10℃ and keep it for 28 min. The cooling rate is 1℃ / min to promote the complete solidification of the colloid and obtain a double-layer jelly. (4) Electrostatically spray a naringin-β-cyclodextrin embedding solution onto the surface of the double-layer jelly. The spraying amount is 8 mg solution / kg double-layer jelly. The voltage of electrostatic spraying is 14 kV and the flow rate is 1.8 mL / min. (5) Irradiate with UV-C for 4 minutes at an intensity of 1.6 mW / cm. 2 Packaging and refrigeration.

[0043] Example 13 A method for preparing a composite plant gum stepwise fermented jelly includes the following steps: (1) Fermentation and preparation of the high elasticity layer: Take 5% konjac powder and 1.5% locust bean gum, mix them evenly and disperse them in 80℃ pure water, stir to dissolve for 10 min, cool to 45℃, add 0.5% yeast extract; inoculate with 550 Lactobacillus plantarum, with an inoculation amount of 1.5×10 7 CFU / mL, adjust pH to 4.0 with lactic acid, ferment at 35℃ for 9h; rapidly cool to 20℃, pour into molds to 50% height, and let stand for 30min to form the lower layer; (2) Fermentation and preparation of temperature-sensitive rapid-melting layer: Mix 0.7% ι-carrageenan, 0.4% sodium alginate, 0.3% low-ester pectin and 0.08% purple cabbage anthocyanin, and dissolve in purified water at 75℃; cool to 40℃, add 0.08% KCl, stir at 250rpm for 5min, add 2% sucrose, and inoculate with Lactobacillus acidophilus LA05 (inoculation amount is 5.5×10 5 CFU / mL) and Kluyveromyces martensii (inoculation amount of 1.5 × 10⁻⁶ CFU / mL) 7 (CFU / mL), adjust pH to 5.5, ferment at 35℃ for 6 hours; slowly pour into the mold with the solidified lower layer until the mold is full; (3) Gradient cooling: First, keep the temperature at 25℃ for 10 min to allow the colloid to initially form a network structure, then cool down to 10℃ and keep it for 30 min. The cooling rate is 1℃ / min to promote the complete solidification of the colloid and obtain a double-layer jelly. (4) Electrostatically spray a naringin-β-cyclodextrin embedding solution onto the surface of the double-layer jelly. The spraying amount is 8 mg solution / kg double-layer jelly. The voltage of electrostatic spraying is 14 kV and the flow rate is 1.8 mL / min. (5) Irradiate with UV-C for 5 minutes at an intensity of 1.6 mW / cm. 2 Packaging and refrigeration.

[0044] Example 14 A method for preparing a composite plant gum stepwise fermented jelly includes the following steps: (1) Fermentation and preparation of the high elasticity layer: Take 5% konjac powder and 1.5% locust bean gum, mix them evenly and disperse them in 80℃ pure water, stir to dissolve for 10 min, cool to 45℃, add 0.5% yeast extract; inoculate with 550 Lactobacillus plantarum, with an inoculation amount of 1.5×10 7 CFU / mL, adjust pH to 4.0 with lactic acid, ferment at 35℃ for 9h; rapidly cool to 20℃, pour into molds to 50% height, and let stand for 30min to form the lower layer; (2) Fermentation and preparation of temperature-sensitive rapid-melting layer: Mix 0.7% ι-carrageenan, 0.4% sodium alginate, 0.3% low-ester pectin and 0.08% purple cabbage anthocyanin, and dissolve in purified water at 75℃; cool to 40℃, add 0.08% KCl, stir at 250rpm for 5min, add 2% sucrose, and inoculate with Lactobacillus acidophilus LA05 (inoculation amount is 5.5×10 5 CFU / mL) and Kluyveromyces martensii (inoculation amount of 1.5 × 10⁻⁶ CFU / mL) 7 (CFU / mL), adjust pH to 5.5, ferment at 35℃ for 6 hours; slowly pour into the mold with the solidified lower layer until the mold is full; (3) Gradient cooling: First, keep the temperature at 25℃ for 15 minutes to allow the colloid to initially form a network structure. Then, cool the temperature to 10℃ and keep it for 25 minutes. The cooling rate is 1℃ / min to promote the complete solidification of the colloid and obtain a double-layer jelly. (4) Electrostatically spray a naringin-β-cyclodextrin embedding solution onto the surface of the double-layer jelly. The spraying amount is 8 mg solution / kg double-layer jelly. The voltage of electrostatic spraying is 14 kV and the flow rate is 1.8 mL / min. (5) Irradiate with UV-C for 4 minutes at an intensity of 1.6 mW / cm. 2 Packaging and refrigeration.

[0045] Comparative Example 1 (no step-by-step fermentation, single-layer jelly) The preparation method of single-layer jelly includes the following steps: (1) Mix 5% konjac powder, 1.5% locust bean gum, 0.7% 1-carrageenan and 0.4% sodium alginate and dissolve at 80℃; (2) Adjust the pH to 5.0 and inoculate with 550 g of Lactobacillus plantarum (1.5 × 10⁻⁶ g). 7 (CFU / mL), fermented at 35℃ for 9 hours; (3) Cool directly to 10℃, cure, and then irradiate with UV-C for 5 minutes at an intensity of 1.6 mW / cm. 2 Packaging and refrigeration.

[0046] Comparative Example 2 (Spraying without β-cyclodextrin embeddings) The preparation method is the same as in Example 7, but step (4) is omitted.

[0047] Comparative Example 3 (High-Temperature Sterilization as a Substitute for UV-C) The preparation method is the same as in Example 7, but step (5) is changed to water bath sterilization at 85℃ / 15min.

[0048] Comparative Example 4 (no gradient cooling, direct cooling) The preparation method is the same as in Example 7, but step (3) is changed to direct cooling at 4°C for 1 hour.

[0049] Comparative Example 5 (no fermentation, only chemical acidification) Preparation method: High-elasticity layer: 5% konjac powder and 1.5% locust bean gum, with lactic acid added directly to adjust the pH to 4.0; Thermosensitive layer: 0.7% ι-carrageenan and 0.4% sodium alginate, with citric acid added to adjust the pH to 5.5; The other steps are the same as in Example 7.

[0050] Performance testing: Gel strength: was measured using a texture analyzer with a P / 5 probe. The lower layer thickness was 15 mm and the upper layer thickness was 10 mm. The measurements were taken separately at a speed of 1 mm / s. Melting time (s): Record the time for complete melting in a 37℃ water bath; Ethyl acetate content: determined by GC-MS (gas chromatography-mass spectrometry).

[0051] The results are shown in Table 2 below: Table 2

[0052]

[0053] As can be seen from Comparative Example 2, it is possible that the β-cyclodextrin encapsulation (containing glycerol) forms a dense film covering the surface of the jelly, creating a physical barrier that prevents the volatilization of ethyl acetate.

[0054] viable count determination: Culture media: MRS agar (lactic acid bacteria), YPD agar (yeast); Conditions: Anaerobic culture at 37℃ for 48 hours (lactic acid bacteria), aerobic culture at 28℃ for 72 hours (yeast).

[0055] The results are shown in Table 3 below: Table 3

[0056]

[0057] Quantitative color difference analysis: Test indicators: ΔE value: characterizes the magnitude of color change (initial color as a reference); RGB / Lab value: records the color coordinates at a specific pH. The results are shown in Table 4 below: Table 4

[0058]

[0059] Note: ΔE > 5 can be clearly identified by the naked eye, and ΔE > 20 has a strong visual impact.

[0060] The ΔE of Example 7 was 25.3, demonstrating that purple cabbage anthocyanins showed significant color development in the pH range of 4.0 to 5.5.

[0061] User interaction rating (sensory experiment): Test design: 30 employees of our company (aged 20-50) were randomly selected to observe the pH color development process of the jelly and rated it from three aspects: fun, visual appeal, and willingness to repeat the experience (1-5 points).

[0062] The results are shown in Table 5 below: Table 5

[0063]

[0064] Color development stability (accelerated test): Test method: Place the jelly in a 40℃ / 75%RH environment and stimulate it alternately with pH4.0 and pH7.0 solutions every day, and record the ΔE value on days 0 / 15 / 30.

[0065] The results are shown in Table 6 below: Table 6

[0066]

[0067] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A composite plant gum stepwise fermented jelly, characterized in that: The jelly has an interesting pH-based color development feature. It is made by fermenting a composite plant colloid through stepwise fermentation under dual pH and temperature control, forming an upper temperature-sensitive and fast-melting layer and a lower highly elastic layer.

2. The composite plant gum stepwise fermented jelly according to claim 1, characterized in that, The composite plant gum in the temperature-sensitive quick-melting layer is carrageenan and sodium alginate; the composite plant gum in the high-elasticity layer is konjac powder and locust bean gum.

3. The method for preparing a composite plant gum stepwise fermented jelly according to claim 1 or 2, characterized in that, The following steps are involved: (1) Fermentation and preparation of high elasticity layer: Take 3-6% konjac powder and 1-2% locust bean gum, mix them evenly and disperse them in 80℃ pure water, stir to dissolve for 10 min, cool to 45℃, add 0.5% yeast extract; inoculate with Lactobacillus plantarum, adjust the pH to 4.0 with lactic acid, ferment at 30-35℃ for 9-10 h; quickly cool to 20℃, pour into mold to 45-55% height, let stand for 30 min to form the lower layer; (2) Fermentation and preparation of temperature-sensitive quick-melting layer: Mix 0.5-0.8% 1-carrageenan, 0.3-0.5% sodium alginate, 0.2-0.4% low-ester pectin and 0.08% purple cabbage anthocyanin, and dissolve in 75℃ purified water; cool to 40℃, add 0.05-0.1% KCl, stir at 200-300rpm for 5min, add 2% sucrose, inoculate with Lactobacillus acidophilus and aroma-producing yeast, adjust pH to 5.0-6.0, and ferment at 30-40℃ for 6h; slowly pour into the mold with the solidified lower layer until the mold is full; (3) Gradient cooling: First, maintain at 25℃ for 10-15 min, then cool down to 10℃ and maintain for 25-30 min to obtain double-layer jelly; (4) Electrostatically spray a solution of naringin-β-cyclodextrin encapsulation onto the surface of the double-layer jelly; (5) Irradiate with UV-C for 4-5 minutes, then package and refrigerate.

4. The method for preparing a composite plant gum stepwise fermented jelly according to claim 3, characterized in that, The inoculation amount of *Lactobacillus plantarum* in step (1) is 1.0 × 10⁻⁶. 7 -2.0×10 7 CFU / mL.

5. The method for preparing a composite plant gum stepwise fermented jelly according to claim 3, characterized in that, In step (2), the inoculation amount of Lactobacillus acidophilus is 5.0 × 10⁻⁶. 5 -6.0×10 5 CFU / mL; the aroma-producing yeast was Kluyveromyces martensii, and the inoculum size was 1.0 × 10⁻⁶. 7 -2.0×10 7 CFU / mL.

6. The method for preparing a composite plant gum stepwise fermented jelly according to claim 3, characterized in that, In step (3), the cooling rate from 25°C to 10°C is 1°C / min.

7. The method for preparing a composite plant gum stepwise fermented jelly according to claim 3, characterized in that, The preparation method of the naringin-β-cyclodextrin encapsulation solution in step (4) is as follows: Step 1: Mix β-cyclodextrin and purified water at a mass ratio of 1:10, heat to 50-60℃, and dissolve with ultrasonic assistance; Step 2: Dissolve naringin in a 30-50% ethanol solution, and slowly add it dropwise to a β-cyclodextrin aqueous solution. Maintain the temperature at 50-60℃ and stir continuously at 200-300 rpm for 4-5 hours. Step 3: High-pressure homogenization at 50-60 MPa, repeated 3 times; Step 4: Spray drying was performed to obtain the naringin-β-cyclodextrin encapsulated compound; Step 5: Disperse the naringin-β-cyclodextrin encapsulated compound in a 5% glycerol solution and stir at 100 rpm for 10 min to obtain the final product.

8. The method for preparing a composite plant gum stepwise fermented jelly according to claim 7, characterized in that, The The molar ratio of β-cyclodextrin in step 1 to naringin in step 2 is 1:1-1.

5.

9. The method for preparing a composite plant gum stepwise fermented jelly according to claim 7, characterized in that, The parameters for spray drying in step 4 are as follows: inlet air temperature: 170-190℃; outlet air temperature: 80-90℃; atomization pressure: 0.3-0.5MPa; feed rate: 5-10L / min.

10. The method for preparing a composite plant gum stepwise fermented jelly according to claim 3, characterized in that, In step (4), the electrostatic spraying voltage is 13-15kV and the flow rate is 1.5-2mL / min.

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