Preparation method of konjaku flour-carrageenan compound ice cream stabilizer and ice cream thereof

Abstract

The invention provides a preparation method of a konjaku flour-carrageenan compound ice cream stabilizer, which comprises the following steps: carrying out enzymolysis on konjaku flour by adopting beta-mannase to obtain enzymolysis konjaku colloid; the preparation method comprises the following steps: premixing carrageenan with sodium citrate and trace potassium chloride, and dissolving in hot water to obtain a carrageenan solution; mixing the enzymolysis konjac colloid with a carrageenan solution, performing high-pressure homogenization, and performing quick-cooling crosslinking to obtain a gel product; premixing CMC powder with ice water, shearing at a high speed to obtain a nanoscale CMC suspension, injecting the nanoscale CMC suspension into a gel product, and stirring to embed CMC molecules into gaps of a konjak-carrageenan network; the konjaku flour compound ice cream stabilizer is obtained. The konjaku flour serving as a main component of the ice cream can inhibit generation of ice crystals in the freezing process, so that the ice cream tastes finer and smoother, ice slag feeling is avoided, and the ice crystal inhibiting effect of the konjaku flour is superior to that of other thickeners.

Description

Technical Field

[0001] The invention relates to a preparation method of a konjac flour-carrageenan compound ice cream stabilizer, belonging to the technical field of food. Background Art

[0002] In ice cream production, stabilizers are key functional ingredients that determine product quality. Early ice cream relied on lecithin from natural ingredients (such as egg yolk) for emulsification. However, the increasing demands of industrial production for texture, melt resistance, and shelf life have driven the use of synthetic stabilizers. Stabilizers' primary functions include hydrogen bonding with water molecules to form a three-dimensional network, inhibiting ice crystal growth; increasing the viscosity of the mix to prevent fat globule aggregation; and, to a certain extent, enhancing the product's melt resistance and improving its smoothness.

[0003] Traditional stabilizers are primarily based on gelatin, but its temperature sensitivity and limited vegetarian appeal have prompted the industry to develop plant-based alternatives. Currently, mainstream stabilizers include polysaccharides such as carrageenan, guar gum, and locust bean gum, which synergistically enhance gel strength; cellulose derivatives such as carboxymethyl cellulose (CMC), which offer excellent water retention and acid resistance; and microbial colloids such as xanthan gum, produced through a fermentation process and resistant to high temperatures, acids, and alkalis. Modern ice cream stabilizer systems are trending toward complex formulations. For example, a carrageenan-locust bean gum combination synergistically enhances whey separation inhibition, while a guar gum-xanthan gum combination balances viscoelastic properties. Furthermore, the "clean label" trend is driving the use of natural colloids, with some companies developing enzymatically modified colloids to reduce additive levels. Future ice cream stabilizer technology will focus on refined functionality (such as compatibility with low-sugar / low-fat formulations) and sustainable sourcing to meet both healthy consumer and environmental demands.

[0004] The patent with publication number CN201610859965.5 discloses an ice cream stabilizer and a preparation method thereof. The stabilizer is mainly composed of sodium carboxymethyl cellulose, sorbitan oleate, lecithin, sodium alginate, disodium hydrogen phosphate, sodium D-isoascorbate and pectin. Although it has a high expansion rate and anti-melting performance, its composition is complex and there are many types of additives; the patent with publication number CN202111172488.2 proposes another ice cream stabilizer and a method of use thereof. The stabilizer formula is 15-30% of Sanzan gum, 20-30% of tamarind gum, and 40-60% of monostearate, which effectively solves the problems of poor freeze-thaw resistance, low stability, many ice crystals, and poor taste. However, Sanzan gum is a microbial polysaccharide artificially developed and produced, and further optimization can be considered in the selection of colloids. Summary of the Invention

[0005] This invention relates to the field of food processing technology, specifically to a composite ice cream stabilizer system primarily composed of konjac flour (glucomannan) and supplemented with kappa-carrageenan, as well as a preparation method and application technology for this stabilizer in ice cream production. By optimizing the synergistic ratio of konjac flour and carrageenan, this solution significantly improves ice cream's melt resistance, texture smoothness, and low-temperature stability. It is suitable for the industrial production of dairy-based, plant-based, and low-fat ice creams.

[0006] The ice cream stabilizer includes the following raw materials in mass fraction: 80%-85% of konjac flour, 10%-18% of carrageenan, 1%-3% of carboxymethyl cellulose (CMC), and 0.5%-1% of sodium citrate.

[0007] Ratio relationship: The mass percentage of konjac flour (80%-85%) and carrageenan (10%-18%). Exceeding this range will lead to an imbalance in gel strength (for example, excessive carrageenan will cause a brittle and hard feeling, and excessive konjac flour will lead to insufficient water holding capacity).

[0008] A method for preparing a konjac flour-carrageenan compound ice cream stabilizer comprises the following steps: (1) Konjac flour pre-enzymatic hydrolysis: β-mannanase is used to enzymatically hydrolyze the konjac flour to obtain enzymatic hydrolyzed konjac colloid. (2) Carrageenan-ion synergistic activation: premix carrageenan with sodium citrate and trace potassium chloride, dissolve in hot water to obtain a carrageenan solution; (3) Dynamic high-pressure homogenization-cold-melt crosslinking: After the enzymatic hydrolyzed konjac colloid is mixed with the carrageenan solution, high-pressure homogenization is performed and then rapid cold crosslinking is performed to obtain a gel product; (4) Premix CMC powder with ice water and shear at high speed to obtain a nano-scale CMC suspension, inject the nano-scale CMC suspension into the gel product, and stir to embed the CMC molecules into the gaps of the konjac-carrageenan network; thus, a konjac flour-based ice cream stabilizer is obtained.

[0009] In the step (1), the enzymatic hydrolysis temperature is 40-50°C, the enzymatic hydrolysis pH is 5.0-5.8, and the enzymatic hydrolysis time is 10-30 minutes.

[0010] In step (1), β-mannanase is used to achieve partial enzymatic hydrolysis, cutting the molecular chain to a molecular weight of 50-100 kDa.

[0011] In some preferred cases, konjac flour is pre-enzymatically hydrolyzed: β-mannanase (enzyme activity 5-8 U / g) is used to partially hydrolyze the konjac flour (temperature 45°C / pH 5.5, time 30 min), cutting the molecular chain to a molecular weight of 50-100 kDa to improve solubility and gel ductility.

[0012] The amount of potassium chloride used in step (2) is 0.05%-0.1% of the total amount of sodium citrate, so as to form a potassium ion-citric acid buffer system.

[0013] In some preferred cases, carrageenan-ion synergistic activation is performed: carrageenan is premixed with sodium citrate and a trace amount of potassium chloride (0.05%-0.1%) and dissolved in hot water at 60°C to form a potassium ion-citric acid buffer system to activate the gelling properties of κ-carrageenan.

[0014] The high-pressure homogenization process in step (3) includes two stages: the first stage high-pressure homogenization condition is 20-30 MPa and the temperature is 50-70°C; the second stage high-pressure homogenization condition is 5-15 MPa and the temperature is 20-40°C.

[0015] The high-pressure homogenization process in step (3) includes two stages: the first stage high-pressure homogenization condition is 25 MPa and the temperature is 55°C; the second stage high-pressure homogenization condition is 10 MPa and the temperature is 40°C.

[0016] After high-pressure homogenization in step (3), the mixture is cooled to 1-4°C at a rate of 20-30°C / min and kept warm for 1-2 hours.

[0017] In some preferred cases, in step (3), the dynamic high-pressure homogenization-cold-melt crosslinking is as follows: after the enzymatically hydrolyzed konjac colloid and the carrageenan solution are mixed, two-stage high-pressure homogenization is performed; the first stage is 25MPa / 55°C (to break up macromolecular aggregates); the second stage is 10MPa / 40°C (to promote hydrogen bond crosslinking between konjac and carrageenan). Subsequently, the mixture is rapidly cooled to 4°C and allowed to stand for 2 hours to complete the cold-induced gel network solidification.

[0018] In the step (4), the mass ratio of CMC powder to ice water is 1:50-60; after mixing, the mixture is stirred at 3000 rpm-6000 rpm for 3-5 minutes to form a CMC suspension.

[0019] In the step (4), the nano-scale CMC suspension is injected into the gel product and stirred at 40-50°C and 100-200 rpm for 10-30 minutes.

[0020] In some preferred cases, the CMC gradient embedding technique involves the following steps: After cold-melt crosslinking, CMC powder is premixed with ice water (2-4°C) at a ratio of 1:50 and dispersed at high shear speed (5000 rpm / 5 minutes) to form a nanoscale CMC suspension. The CMC suspension is then slowly injected into the gel system and stirred at low speed (200 rpm) for 30 minutes at 45°C to allow the CMC molecules to embed into the gaps in the konjac-carrageenan network. The resulting konjac flour-based ice cream stabilizer is then packaged and refrigerated for later use.

[0021] The present invention also includes ice cream, the raw materials of which include the konjac flour-carrageenan compound ice cream stabilizer prepared by the method.

[0022] Konjac flour, a natural polysaccharide extracted from konjac tubers, is a major component of glucomannan, a plant-based food ingredient with high water retention, thermal stability, and excellent gel-forming ability. It is a clean-label plant-based food ingredient. Konjac flour is a micronized powder made from the highly viscous konjac flower with a 200-mesh particle size. In ice cream applications, it forms a three-dimensional gel network that encapsulates free water molecules, effectively inhibiting ice crystal growth and enhancing the delicate texture. Furthermore, as a high-viscosity colloid, it slows the melting of ice cream and increases its overrun, resulting in a lighter texture.

[0023] Carrageenan, a natural hydrophilic polysaccharide extracted from red algae seaweeds (such as Chondrus crispus and Eucheuma), is a major component of sulfated galactans. κ-carrageenan is the most commonly used type of ice cream stabilizer due to its excellent gel stability and melt resistance. In ice cream, it inhibits ice crystal formation, improves melt resistance, and imparts a smooth texture, avoiding a gritty texture.

[0024] Carboxymethyl cellulose, a natural cellulose derivative used in ice cream stabilizers, meets the requirements of green chemistry and sustainable development. Carboxymethyl cellulose is widely used in the food industry as a thickener, stabilizer, humectant, and emulsifier. Adding CMC to ice cream can improve taste and extend shelf life.

[0025] Sodium citrate, an organic compound in ice cream stabilizers, is a food additive. It serves as an emulsifier and stabilizer in ice cream, as well as a rancidity preventer for dairy products and a sweetening agent for foods. According to my country's "Hygienic Standards for the Use of Food Additives," the dosage should be based on normal production needs.

[0026] The present invention discloses an ice cream stabilizer and a method for using the same. The composite ice cream stabilizer is a pure plant-based colloid and can be added in a small amount during the ice cream production process. The slurry has an appropriate viscosity, and the finished ice cream has a fluffy and delicate taste. The excellent water-holding and gel-forming abilities of konjac flour give the ice cream better melt resistance and texture. The synergistic effect of konjac flour and carrageenan further enhances the texture and low-temperature stability of the ice cream. The stabilizer is also applicable to industrial production in milk-based, plant-based, and low-fat ice cream formulas.

[0027] Advantages of this patent 1. Texture optimization: This composite ice cream stabilizer has super water-holding capacity (up to 100 times its own weight), forming a stable gel network, which significantly improves the texture and melting resistance of ice cream.

[0028] 2. Taste advantage: Konjac flour, as the main ingredient of ice cream, can inhibit the formation of ice crystals during the freezing process, making it taste more delicate and smooth, avoiding the feeling of ice chips, and is better than other thickeners in inhibiting ice crystals.

[0029] 3. Cost-effectiveness: Konjac flour has multiple functions such as thickening, stabilization, emulsification, and gelling. It can replace or reduce the use of other additives. The addition amount is low (usually 0.1%-0.3%), but the effect is significant and cost-effective.

[0030] A phased gradient activation-cross-linking process and CMC gradient embedding technology are used in ice cream stabilizers. The water retention of konjac flour after enzymatic hydrolysis is increased by 40% and the viscosity is reduced by 30%, avoiding the energy consumption problem of traditional high-temperature hydration. The gel strength is then optimized through ion regulation (the ratio of K⁺ to Na⁺), and finally molecular directional cross-linking is achieved through temperature-controlled homogenization.

[0031] Molecular interaction: Hydrogen bond-ionic bond collaborative network, the hydroxyl groups of konjac flour combine with the sulfate groups of carrageenan to form a composite gel structure of "rigid skeleton (konjac) + flexible filler (carrageenan)"; Enhanced anti-melting property: The melting temperature of the composite gel is increased to 50-55°C (single konjac gum is only 42-45°C), and the melting rate is reduced by more than 30%.

[0032] Application scenario expansion Product applications can cover dairy-based ice cream, plant-based (soy milk / coconut milk) ice cream, low-fat / low-sugar functional ice cream, frozen desserts (sorbet, mousse) and industrial-grade ice cream. DETAILED DESCRIPTION

[0033] Raw material specification limits Konjac flour purity ≥90% (glucomannan content), particle size 120 mesh or above, can achieve rapid dissolution effect; carrageenan is limited to κ-type (gel strength ≥800g / cm 2 ), excluding other types of interference.

[0034] The method for preparing ice cream containing an ice cream stabilizer in an embodiment of the present invention comprises the following process steps: S1 ingredients: 100g cream, 100g sugar, 90g whole milk powder, 75g coconut oil or palm oil, 40g maltodextrin, 30g whey powder, 1g monostearate, 0.1%-0.3% stabilizer, and make up the balance to 1kg with water for later use; S2 hydration: Mix the raw materials evenly, and then stir at 60°C-65°C for 30-45 minutes to obtain a hydrated slurry; S3 sterilization: pasteurize the hydrated slurry at 85°C±1°C for 5-10 minutes; S4 homogenization: homogenization temperature 65-70°C, homogenization pressure 20-25MPa, homogenization 2 times; S5 aging: aging temperature 0-4°C, aging time 12-36h, first stage aging at 4°C for 12h, second stage aging at 0°C for 12-24h; S6 Finished product: The aged slurry is frozen, filled and quick-frozen to obtain the finished ice cream.

[0035] Table 1 shows the sensory evaluation table and comparison of evaluation results for ice cream products.

[0036] Example 1 1. Staged gradient activation-crosslinking process (1) Pre-enzymatic hydrolysis of konjac flour: β-mannanase (enzyme activity 5-8 U / g) was used to partially hydrolyze the konjac flour (temperature 45℃ / pH 5.5, time 30 min), cutting the molecular chain to a molecular weight of 95-100 kDa, thereby improving solubility and gel ductility.

[0037] (2) Carrageenan-ion synergistic activation: Carrageenan was premixed with sodium citrate and a trace amount of potassium chloride (0.05 wt% relative to citric acid) and dissolved in hot water at 60 °C to form a potassium ion-citric acid buffer system to activate the gel properties of κ-carrageenan.

[0038] (3) Dynamic high-pressure homogenization-cold-melt crosslinking: After the enzymatically hydrolyzed konjac colloid and carrageenan solution were mixed, two-stage high-pressure homogenization was performed; the first stage was 25 MPa / 55°C (to break up macromolecular aggregates); the second stage was 10 MPa / 40°C (to promote hydrogen bond crosslinking between konjac and carrageenan). The temperature was then lowered from the starting temperature to 4°C at a rate of 20°C / min, and the solution was allowed to stand at 4°C for 2 hours to complete the cold-induced gel network solidification.

[0039] 2. CMC gradient embedding technology Specific steps: After cold-melt crosslinking is complete, premix CMC powder with ice water (2-4°C) at a mass ratio of 1:50. High-speed shear dispersion (5000 rpm / 5 minutes) is applied to form a nanoscale CMC suspension. The CMC suspension is then slowly injected into the gel system and stirred at low speed (200 rpm) for 30 minutes at 45°C to allow the CMC molecules to embed into the gaps in the konjac-carrageenan network. The resulting konjac flour-based ice cream stabilizer is packaged and refrigerated for later use.

[0040] Example 2 The method and steps are the same as those in Example 1, except that in step (1), the enzyme is hydrolyzed to a molecular weight of 80-85 kDa.

[0041] Example 3 The method and steps are the same as those in Example 1, except that in step (3), the first-level high-pressure homogenization conditions are 20 MPa and the temperature is 50°C; the second-level high-pressure homogenization conditions are 15 MPa and the temperature is 40°C.

[0042] Example 4 The method and steps are the same as those in Example 1, except that in step (3), the first-level high-pressure homogenization conditions are 30 MPa and the temperature is 70°C; the second-level high-pressure homogenization conditions are 5 MPa and the temperature is 20°C.

[0043] Example 5 The method and steps are the same as those in Example 1, except that in step (3), after high-pressure homogenization, the mixture is cooled to 0°C at a rate of 30°C / min and kept warm for 1 hour.

[0044] Comparative Example 1 The method and steps are the same as those in Example 1, except that the enzymatic hydrolysis in step (1) is complete and the molecular weight is reduced to 130-150 kDa.

[0045] Comparative Example 2 The method and steps are the same as those in Example 1, except that in step (3), only the first high-pressure homogenization is performed at low pressure and low temperature, and the second high-pressure homogenization is performed at high pressure and high temperature. Specifically, the first-level high-pressure homogenization conditions are 10 MPa and the temperature is 40°C; the second-level high-pressure homogenization conditions are 25 MPa and the temperature is 55°C.

[0046] The stabilizer obtained in the embodiment and comparative example was used to prepare ice cream, and the method for preparing ice cream was the same as above.

[0047]

[0048] From the technical solution of this application, the ice cream prepared with the stabilizer in this application has similar technical effects as Bright Dairy Brick, Baxi Vanilla Ice Cream, and Oatly Oatmeal Ice Cream. The konjac raw material used in this application has expanded its market application. Konjac, as a food raw material, can reduce the amount of food additives in the stabilizer to a certain extent, making it more natural and healthy. At the same time, konjac contains the dietary fiber required by the human body every day, which makes people feel full after eating it.

Claims

1. A method for preparing a konjac flour-carrageenan compound ice cream stabilizer, characterized in that: The steps include: (1) Konjac flour pre-enzymatic hydrolysis: β-mannanase is used to enzymatically hydrolyze the konjac flour to obtain enzymatically hydrolyzed konjac colloid; (2) Carrageenan-ion synergistic activation: premix carrageenan with sodium citrate and trace potassium chloride, dissolve in hot water to obtain a carrageenan solution; (3) Dynamic high-pressure homogenization-cold-melt crosslinking: After the enzymatic hydrolyzed konjac colloid is mixed with the carrageenan solution, high-pressure homogenization is performed and then rapid cold crosslinking is performed to obtain a gel product; (4) Premix CMC powder with ice water and shear at high speed to obtain a nano-scale CMC suspension, inject the nano-scale CMC suspension into the gel product, and stir to embed the CMC molecules into the gaps of the konjac-carrageenan network; thus, a konjac flour-based ice cream stabilizer is obtained.

2. The method for preparing the konjac flour-carrageenan composite ice cream stabilizer according to claim 1, wherein In step (1), the enzymatic hydrolysis temperature is 40-50° C., the enzymatic hydrolysis pH is 5.0-5.8, and the enzymatic hydrolysis time is 10-30 min.

3. The method for preparing the konjac flour-carrageenan composite ice cream stabilizer according to claim 1, wherein In step (1), β-mannanase is used to achieve partial enzymatic hydrolysis, cutting the molecular chain to a molecular weight of 50-100 kDa.

4. The method for preparing the konjac flour-carrageenan composite ice cream stabilizer according to claim 1, wherein The amount of potassium chloride used in step (2) is 0.05%-0.1% of the total amount of sodium citrate, so as to form a potassium ion-citric acid buffer system.

5. The method for preparing the konjac flour-carrageenan composite ice cream stabilizer according to claim 1, wherein The high-pressure homogenization process used in step (3) includes two stages: the first stage high-pressure homogenization condition is 20-30 MPa and the temperature is 50-70°C; the second stage high-pressure homogenization condition is 5-15 MPa and the temperature is 20-40°C.

6. The method for preparing the konjac flour-carrageenan compound ice cream stabilizer according to claim 5, wherein: The high-pressure homogenization process used in step (3) includes two stages: the first stage high-pressure homogenization condition is 25 MPa and the temperature is 55°C; the second stage high-pressure homogenization condition is 10 MPa and the temperature is 40°C.

7. The method for preparing the konjac flour-carrageenan composite ice cream stabilizer according to claim 5 or 6, wherein: After high-pressure homogenization in step (3), the mixture is cooled to 1-4°C at a rate of 20-30°C / min and kept warm for 1-2 hours.

8. The method for preparing the konjac flour-carrageenan compound ice cream stabilizer according to claim 1, wherein In step (4), the mass ratio of CMC powder to ice water is 1:50-60; after mixing, the mixture is stirred at 3000 rpm-6000 rpm for 3-5 minutes to form a CMC suspension.

9. The method for preparing the konjac flour-carrageenan compound ice cream stabilizer according to claim 1, wherein In step (4), the nano-scale CMC suspension is injected into the gel product and stirred at 40-50° C. and 100-200 rpm for 10-30 min.

10. An ice cream, characterized in that: The raw materials include a konjac flour-carrageenan compound ice cream stabilizer prepared by the method described in any one of claims 1 to 9.

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