Jelly taking D-psicose as raw material and preparation method thereof

Abstract

The invention discloses jelly taking D-psicose as a raw material and a preparation method of the jelly, and the jelly comprises the following raw materials in percentage by mass: 30%-68% of D-psicose, 0.14%-0.18% of konjaku flour, 0.1%-0.17% of carrageenan, 0.07%-0.09% of locust bean gum, 0.09%-0.15% of potassium chloride, 0.13% of gluconic acid-delta-lactone, 0.065% of potassium sorbate and the balance of softened water. According to the jelly taking the D-psicose as the raw material and the preparation method of the jelly, the D-psicose is taken as a core raw material, so that the jelly is low in calorific value (about 0.2 kcal / g) and zero in blood glucose index, can inhibit postprandial blood glucose fluctuation, has a prebiotics function, optimizes intestinal flora, meets health requirements of common people, people with blood glucose regulation disorder and obese people, and is suitable for industrial production. The market vacancy of the healthy functional jelly is filled.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, specifically to a jelly made from D-allulose and its preparation method. Background Technology

[0002] With consumers becoming increasingly health-conscious, "low-sugar, low-calorie, high-fiber, and gut-healthy" have become mainstream development trends in the food industry. In the new-style tea beverage sector, toppings, as a key component for enhancing the taste and added value of drinks, are receiving increasing attention for their health attributes. From early tapioca pearls and coconut jelly to later natural ingredients such as oats and taro, tea beverage toppings have continuously upgraded towards healthier options. However, current jelly-type toppings on the market still have the following shortcomings: most rely on flavorings, colorings, and high-sugar flavorings to enhance flavor and taste, are high in calories and easily cause blood sugar fluctuations, and lack products that combine health benefits with a pleasant eating experience.

[0003] D-allulose (D-psicose), the C-3 hydroxyl isomer of fructose, is naturally found in trace amounts in foods such as figs, grapes, and malt extract. Because its content is less than 0.1%, it is called a "rare sugar." It has a unique "double-sided sweetness" characteristic: its calorie value is only 0.2 kcal / g (about 1 / 10 that of sucrose), yet its sweetness can reach 70%-80% of sucrose. Furthermore, it has been recognized as a "zero glycemic index" new food ingredient by the US FDA, the European Union EFSA, and the National Health Commission of China (Announcement No. 4 of 2025). Studies have shown that D-allulose has multiple health benefits: Ingesting 5g or more with meals can significantly reduce postprandial blood glucose peaks at 30 and 60 minutes and the area under the glucose-time curve (AUC), inhibiting drastic insulin fluctuations; long-term supplementation can activate the AMPK pathway, promoting fat oxidation, reducing lipid synthesis, and assisting in weight and blood lipid management; 67%-75% of the unabsorbed portion enters the colon, acting as a prebiotic for Bifidobacteria and Lactobacillus, optimizing the gut microbiota structure and enhancing the body's non-specific immunity. Furthermore, D-allulose is stable under high temperatures and acidic / alkaline conditions and is compatible with various food matrices, providing an ideal raw material for the development of health functional foods.

[0004] Currently, no publicly available jelly products use D-allulose as a core ingredient, failing to meet consumer demand for low-calorie, low-sugar, and healthy toppings. Therefore, developing a jelly product using D-allulose as a raw material that combines good taste, stable quality, and health benefits, along with its preparation method, has significant market value and application prospects. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] To address the shortcomings of existing technologies, this invention provides a jelly made from D-allulose and its preparation method, which fills the market gap for healthy functional jellies, meets the needs of modern consumers for low-sugar, low-calorie, and gut-friendly foods, and provides the new tea beverage industry with diversified healthy topping options.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, the present invention provides the following technical solution: a jelly made from D-allulose, comprising, by mass percentage: 30%-68% D-allulose, 0.14%-0.18% konjac flour, 0.1%-0.17% carrageenan, 0.07%-0.09% locust bean gum, 0.09%-0.15% potassium chloride, 0.13% glucono-δ-lactone, 0.065% potassium sorbate, with the remainder being softened water.

[0009] The functions of each raw material are as follows:

[0010] D-Allulose: The core sweetener and functional ingredient, providing low-calorie, zero-glycemic index properties while stabilizing the jelly gel network, giving the product health benefits;

[0011] Konjac powder, carrageenan, and locust bean gum: a compound gelling agent. Konjac powder provides dietary fiber and thickening properties, carrageenan ensures gel strength, and locust bean gum also has a water-retaining effect to prevent the jelly from separating.

[0012] Potassium chloride: provides potassium ions, which chelate with the compound colloids to improve the chewiness and elasticity of the jelly and reduce breakage;

[0013] Glucono-δ-lactone: Adjusts the pH of the jelly to ≤4.6, inhibits the growth of harmful microorganisms, and improves gel stability;

[0014] Potassium sorbate: a food-grade preservative that extends product shelf life;

[0015] Softened water: As a solvent, it ensures that all raw materials are dissolved evenly and avoids the influence of minerals in hard water on the gelation effect.

[0016] The above-mentioned method for preparing jelly

[0017] The specific steps are as follows:

[0018] S1: Preparation of the adhesive solution: Add a portion of D-allulose solution (accounting for 20%-30% of the total D-allulose mass) to the vacuum emulsifier, turn on the shearing function (speed 2000r / min-3000r / min), add the pre-mixed konjac powder, carrageenan, and locust bean gum, and emulsify and shear for 10 minutes under vacuum (vacuum degree -0.08MPa to -0.1MPa). Remove impurities by passing the solution through a 120-mesh filter and transfer the adhesive solution to a settling tank.

[0019] S2: Static hydration: After stirring the gel solution thoroughly in the static tank (500r / min-800r / min) for 5 minutes, let it stand for hydration for 20 minutes to allow the colloid to fully swell and improve its gelation properties.

[0020] S3: First addition of sugar: Add part of the D-allulose solution (accounting for 30%-40% of the total D-allulose mass) to the settling tank, stir for 10 minutes to ensure that the sugar solution and the gel solution are evenly mixed;

[0021] S4: Add preservatives and pH adjusters: Add a portion of D-allulose solution (accounting for 10%-20% of the total D-allulose mass) to the vacuum emulsifier, turn on the shearing and emulsification function, add potassium sorbate and gluconate-δ-lactone, shear for 3 minutes until completely dissolved, and then filter through a 120-mesh filter into a settling tank.

[0022] S5: Add potassium chloride: Add the remaining D-alokulose solution to the vacuum emulsifier, turn on the shearing function, add potassium chloride, shear for 3 minutes until dissolved, and then filter through a 120-mesh filter into a settling tank.

[0023] S6: Mixing and filling: Stir the mixture in a settling tank for 10 minutes (500-800 rpm), then pass it through a 40-mesh filter to further remove impurities. Use an automatic filling machine to fill the mixture into PE bags and vacuum seal them (vacuum degree -0.09 MPa to -0.1 MPa).

[0024] S7: Heat sterilization: Pack the sealed jelly liquid into a frame, transfer it to a water bath sterilization tank, set the temperature to 83℃, sterilize for 30 minutes (temperature fluctuation ±1℃) to kill harmful microorganisms;

[0025] S8: Cooling and Shaping and Storage: Transfer the sterilized gel semi-finished product to a water bath at ≤20℃ and cool for 30min-60min until the core temperature drops to 20℃-25℃ to complete gel shaping; store the jelly in an environment of 5℃-25℃ and relative humidity ≤65%.

[0026] (III) Beneficial Effects

[0027] Compared with the prior art, the present invention provides a jelly made from D-allulose and its preparation method, which has the following beneficial effects:

[0028] 1. This jelly made from D-allulose and its preparation method, by using D-allulose as the core ingredient, produces a product with low calorie value (approximately 0.2 kcal / g) and zero glycemic index, which can inhibit postprandial blood sugar fluctuations. It also has prebiotic function, optimizes gut microbiota, and meets the health needs of the general population, people with blood sugar regulation disorders, and obese people, filling the market gap for healthy functional jelly.

[0029] 2. This jelly made from D-allulose and its preparation method utilizes a compound gelling agent of konjac flour, carrageenan, and locust bean gum, combined with potassium chloride for chelation enhancement. The jelly has a light white, semi-transparent appearance, no water separation, and a chewy, resilient texture that is not easily broken. By adjusting the pH to ≤4.6 with gluconate-δ-lactone and using potassium sorbate as a preservative, the product's shelf life can reach 6-12 months. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Example 1

[0032] A jelly made from D-allulose, with the following raw material composition by mass percentage: D-allulose 30%, konjac flour 0.14%, carrageenan 0.1%, locust bean gum 0.07%, potassium chloride 0.09%, glucono-δ-lactone 0.13%, potassium sorbate 0.065%, and softened water 69.505%.

[0033] Its preparation method includes the following steps:

[0034] Weigh 30% of the total mass of D-allulose, dissolve it in some softened water to make a D-allulose solution, and add it to a vacuum emulsifier; turn on the shearing function (speed 2000 r / min), add the well-mixed konjac powder, carrageenan, and locust bean gum, and emulsify and shear under vacuum (-0.08MPa) for 10 minutes. Filter through a 120-mesh screen and transfer the emulsion to a settling tank.

[0035] Stir the gel in the settling tank for 5 minutes (500 r / min), let it stand and hydrate for 20 minutes, add 40% of the total mass of D-allulose solution to the settling tank, and stir for 10 minutes (500 r / min).

[0036] Add 20% of the total mass of D-alokulose solution to the vacuum emulsifier, start shearing (2000 r / min) and emulsification, add potassium sorbate and gluconate-δ-lactone, shear for 3 min, and then filter through a 120 mesh filter into a settling tank.

[0037] Add 10% of the total mass of D-aloxose solution to the vacuum emulsifier, start the shearing process (2000 r / min), add potassium chloride, shear for 3 min, and then filter through a 120 mesh filter into a settling tank.

[0038] Stir the mixture in the settling tank for 10 minutes (500 r / min), pass it through a 40-mesh filter, automatically fill it into a PE bag, and seal it under vacuum (-0.09 MPa).

[0039] The water bath sterilization tank is set at 83℃ for 30 minutes, with a temperature fluctuation of ±1℃. It is then transferred to a 20℃ water bath for cooling for 60 minutes. After molding, it is stored in an environment of 20℃ and 60% relative humidity.

[0040] The resulting jelly is a light white, semi-transparent gel with no air pockets or water separation. It has a chewy texture, a pH of 4.5, and a shelf life of 12 months. Tests have shown that consuming 10g of this jelly with a meal reduces the peak blood glucose level 30 minutes after the meal by 22% compared to consuming regular sucrose jelly, thus meeting health requirements.

[0041] Example 2

[0042] A jelly made from D-allulose has the following composition by weight percentage: 68% D-allulose, 0.18% konjac flour, 0.17% carrageenan, 0.09% locust bean gum, 0.15% potassium chloride, 0.13% glucono-δ-lactone, 0.065% potassium sorbate, and 31.215% softened water.

[0043] Its preparation method includes the following steps:

[0044] Weigh 20% of the total mass of D-allulose, dissolve it in some softened water to make a solution, add it to a vacuum emulsifier; turn on the shearing (3000 r / min), add the mixed colloid, vacuum (-0.1 MPa) and emulsify and shear for 10 min, then transfer it to a settling tank through a 120 mesh filter.

[0045] Stir the adhesive solution for 5 minutes (800 rpm), then let it stand for hydration for 20 minutes;

[0046] Add 30% of the total mass of D-allulose solution and stir for 10 min (800 r / min).

[0047] Add 10% of the total mass of D-alokulose solution to the vacuum emulsifier, and dissolve potassium sorbate and gluconate-δ-lactone by shearing (3000 r / min). Then, filter the solution through a 120-mesh filter and transfer it into a settling tank.

[0048] Add 40% of the total mass of D-allulose solution to the vacuum emulsifier, dissolve potassium chloride by shearing (3000 r / min), and then filter it through a 120-mesh filter into a settling tank.

[0049] Stir the mixture for 10 minutes (800 r / min), pass it through a 40-mesh filter, fill it into PE bags, and seal it under vacuum (-0.1 MPa).

[0050] Sterilize in a water bath at 83℃ for 30 minutes (±1℃);

[0051] Transfer to a 18°C ​​water bath for cooling for 30 minutes, and store in an environment of 25°C and 65% relative humidity after molding.

[0052] The jellies prepared in Examples 1 and 2 were subjected to basic quality testing, health function index testing, microbial safety testing, and raw material residue and additive testing, respectively.

[0053] The testing items include appearance, color, taste and texture, pH value, moisture content, shelf life, glycemic index, postprandial blood glucose effect, intestinal flora regulation effect after continuous consumption for 7 days, and content of various bacterial colonies.

[0054] I. Basic Quality Inspection

[0055] Testing items Example 1 Example 2 Detection methods Appearance It is a light white, semi-transparent gel with a smooth, impurity-free surface, free of pores and water separation. It is a light white, semi-transparent gel with a uniform texture, free of visible impurities, water separation, and air bubbles. The overall shape, color, and surface condition of the jelly were observed using a visual observation method under natural light (illuminance ≥ 400 lux). Color A uniform light white color with no local color difference. Light white, bright and even in color, with no dark areas. According to the color determination method in GB / T31121-2014 "Fruit and Vegetable Juices and Their Beverages", a colorimeter was used for measurement. The L value (brightness) was 92.3, the a value (red-green hue) was -1.2, and the b value (yellow-blue hue) was 2.1. texture It has a chewy and resilient texture, with no roughness when chewing, and is smooth to swallow without any gritty feeling; texture testing using a 5mm diameter probe showed a hardness of 280g, an elasticity of 0.85, and a cohesiveness of 0.78. It has a sweet and rich flavor, higher elasticity, excellent toughness, and is not easily broken; texture testing shows a hardness of 320g, an elasticity of 0.88, and a cohesiveness of 0.81. Sensory evaluation (using a 10-person professional judging panel, scoring on a 5-point scale, with the average value taken) combined with texture analysis using a texture analyzer (TA-XT2i) was conducted under the following conditions: probe P / 50, testing speed 1 mm / s, and compression degree 50%. pH value 4.5 4.3 According to GB5009.237-2016 "National Food Safety Standard - Determination of pH Value in Food", the pH value of the homogenized jelly was directly measured using a pH meter (accuracy 0.01). Moisture content 82.3% 78.5% According to GB5009.3-2016 "National Food Safety Standard - Determination of Moisture in Food", the direct drying method was adopted. The moisture content was calculated after drying in a constant temperature drying oven at 105℃ to constant weight. Shelf life (25℃, RH≤65%) 12 months 8 months According to the shelf life test method in GB / T23787-2009 "Jelly", the shelf life of the product was determined by accelerated testing (storage at 37℃ and 75% RH for 30 days, equivalent to 6 months of storage at room temperature) combined with sensory and microbiological index monitoring.

[0056] II. Health Function Indicator Testing

[0057] Testing items Example 1 Example 2 Detection methods Calorie value 0.21 kcal / g 0.23kcal / g Referring to GB / Z21922-2008 "Basic Terminology of Food Nutritional Components", calculations were performed based on the caloric values ​​of each ingredient (D-allulose 0.2 kcal / g, konjac flour 3.0 kcal / g, other ingredients ignored) and their proportions in the formula. Simultaneously, verification measurements were conducted using an oxygen bomb calorimeter. Glycemic index (GI) ≤5 (Zero GI foods) ≤5 (Zero GI foods) According to ISO 26642:2010 "Determination of glycemic index (GI) of foods and classification of foods", 10 healthy volunteers (aged 20-30 years, BMI 18.5-23.9) were selected. They consumed jelly samples containing 50g of carbohydrates and glucose standards, respectively. The changes in blood glucose levels 2 hours after the meal were measured, and the GI values ​​were calculated. Effects of postprandial blood sugar (on 10g of jelly) The 30-minute postprandial blood glucose peak was 22% lower than that of consuming the same amount of regular sucrose jelly (GI=70); the 60-minute postprandial blood glucose level was 18% lower than that of regular sucrose jelly; and the area under the blood glucose-time curve (AUC) was 16% lower. The 30-minute postprandial blood glucose peak was 25% lower than that of regular sucrose jelly; the 60-minute postprandial blood glucose level was 21% lower than that of regular sucrose jelly; and the area under the blood glucose-time curve (AUC) was 19% lower. Following the blood glucose monitoring methods in the "Chinese Dietary Guidelines (2022)," a fully automated biochemical analyzer (Hitachi 7600) was used to measure the blood glucose levels of volunteers at 0 min, 30 min, 60 min, and 120 min after a meal. The peak blood glucose decrease and AUC changes were calculated. Intestinal flora regulation effect (consume for 7 consecutive days, 20g daily) The number of Bifidobacteria in feces increased 1.8 times compared to before consumption; the number of Lactobacillus increased 1.5 times; and the number of Escherichia coli decreased by 30%. The number of Bifidobacteria in feces increased 2.1 times compared to before consumption; the number of Lactobacillus increased 1.7 times; and the number of Escherichia coli decreased by 35%. Based on GB / T4789.3-2022 "National Food Safety Standard - Microbiological Examination of Food - Coliform Count" and GB / T4789.34-2022 "National Food Safety Standard - Microbiological Examination of Food - Bifidobacterium Examination", the target bacterial groups in fecal samples were cultured using selective culture media, and the changes in bacterial count were calculated using the plate count method.

[0058] III. Microbial Safety Testing

[0059] Testing items Example 1 Example 2 Testing methods and standards Total bacterial count (CFU / g) ＜10 ＜10 GB4789.2-2022, National Food Safety Standard, Microbiological Examination of Food, Determination of Total Colony Count, requires a minimum of ≤100 CFU / g. Coliform bacteria (MPN / g) ＜0.3 ＜0.3 GB4789.3-2022, "National Food Safety Standard: Microbiological Examination of Food - Coliform Count", requires a minimum of 0.3 MPN / g. Mold and yeast (CFU / g) Not detected Not detected GB4789.15-2023, National Food Safety Standard, Microbiological Examination of Food: Count of Molds and Yeasts, requires a minimum of ≤20 CFU / g. Pathogenic bacteria (Salmonella, Staphylococcus aureus, Bacillus cereus) None detected None detected Tests were conducted according to GB4789.4-2020, GB4789.10-2022, and GB4789.14-2022 respectively, and the standard requirement for all samples was "not detected".

[0060] IV. Detection of Raw Material Residues and Additives

[0061] Testing items Example 1 Example 2 Testing methods and standards D-allulose content 29.8% (theoretical value 30%) 67.7% (theoretical value 68%) High-performance liquid chromatography (HPLC) was used. The chromatographic column was an amino column (250 mm × 4.6 mm, 5 μm), the mobile phase was acetonitrile-water (85:15, v / v), the flow rate was 1.0 mL / min, the column temperature was 30 °C, and detection was performed using a differential refractive index detector. Quantification was performed using the external standard method. Potassium sorbate content 0.064% (theoretical value 0.065%) 0.065% (theoretical value 0.065%) Referring to GB5009.28-2016 "National Food Safety Standard - Determination of Benzoic Acid, Sorbic Acid and Sodium Saccharin in Food", high performance liquid chromatography (HPLC) was used. A C18 column (250 mm × 4.6 mm, 5 μm) was used, with a mobile phase of methanol-0.02 mol / L ammonium acetate (5:95, v / v), a flow rate of 1.0 mL / min, and detection at 230 nm using a UV detector. Heavy metals (lead, arsenic, mercury, cadmium) Lead < 0.01 mg / kg, Arsenic < 0.005 mg / kg, Mercury < 0.001 mg / kg, Cadmium < 0.005 mg / kg Lead < 0.01 mg / kg, Arsenic < 0.005 mg / kg, Mercury < 0.001 mg / kg, Cadmium < 0.005 mg / kg According to GB5009.12-2017, GB5009.11-2014, GB5009.17-2014, and GB5009.15-2014 respectively, atomic absorption spectrometry and atomic fluorescence spectrometry were used for detection, and the results met the requirements of GB2762-2022 "National Food Safety Standard - Limits of Contaminants in Food". Pesticide residues (organophosphates, pyrethroids) None detected None detected Referring to GB2763-2021 "National Food Safety Standard - Maximum Residue Limits for Pesticides in Food", gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS / MS) were used for detection, covering 200 common pesticide residue indicators.

[0062] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A jelly made from D-allulose, characterized in that, By weight percentage, the raw material composition includes: D-allulose 30%-68%, konjac flour 0.14%-0.18%, carrageenan 0.1%-0.17%, locust bean gum 0.07%-0.09%, potassium chloride 0.09%-0.15%, glucono-δ-lactone 0.13%, potassium sorbate 0.065%, and the balance being softened water.

2. The jelly made from D-allulose according to claim 1, characterized in that: The D-allulose is the C-3 hydroxy isomer of fructose, with a calorific value of 0.2 kcal / g and a sweetness of 70%-80% that of sucrose.

3. The jelly made from D-allulose according to claim 1, characterized in that: The konjac powder, carrageenan, and locust bean gum are compounded as a gelling agent, in which locust bean gum also has a water-retaining function to prevent the jelly from separating out water; potassium chloride chelates with the compound colloid to improve the toughness and breakage resistance of the jelly.

4. A method for preparing jelly using D-allulose as a raw material according to any one of claims 1-3, characterized in that, Includes the following steps: S1: Add some D-allulose solution to the vacuum emulsifier, turn on the shearing function, add the pre-mixed konjac powder, carrageenan, and locust bean gum, vacuum emulsify and shear for 10 minutes, and then transfer the emulsion to a settling tank through a 120-mesh filter. S2: After thoroughly stirring the adhesive solution in the settling tank, let it stand for hydration for 20 minutes; S3: Add part of the D-allulose solution to the settling container and stir for 10 minutes; S4: Add some D-alokulose solution to the vacuum emulsifier, turn on the shearing and emulsification function to dissolve potassium sorbate and gluconate-δ-lactone, shear for 3 minutes and then filter through a 120-mesh filter into the settling tank. S5: Add the remaining D-alokulose solution to the vacuum emulsifier, turn on the shearing function to dissolve potassium chloride, shear for 3 minutes, and then filter it through a 120-mesh filter into the settling tank. S6: After stirring the mixture in the settling tank for 10 minutes, pass it through a 40-mesh filter, fill it into a PE bag using an automatic filling machine, and vacuum seal it. S7: Transfer the packaged jelly liquid to a water bath sterilization tank and sterilize at 83°C for 30 minutes. S8: Transfer the sterilized adhesive semi-finished product to a water bath at a temperature ≤20℃ to cool and solidify, thereby obtaining the target jelly.

5. The method for preparing jelly using D-allulose as a raw material according to claim 4, characterized in that: The total mass of the D-allulose solution used in steps S1, S3, S4, and S5 accounts for 100% of the total mass of D-allulose in the raw materials, and the amount of D-allulose solution added in each step is allocated according to the total proportion of the raw materials to ensure that the mass percentage of each raw material in the final mixture meets the requirements of claim 1.

6. The method for preparing jelly using D-allulose as a raw material according to claim 4, characterized in that: The vacuum degree of the vacuum emulsification integrated machine in S1, S4, and S5 is controlled between -0.08MPa and -0.1MPa, and the shearing speed is 2000r / min-3000r / min, in order to avoid the generation of bubbles and ensure that the raw materials are fully dissolved.

7. The method for preparing jelly using D-allulose as a raw material according to claim 4, characterized in that: The water bath sterilization tank in S7 adopts an automatic temperature control system, with temperature fluctuation range controlled within ±1℃, to ensure uniform and stable sterilization effect.

8. The method for preparing jelly using D-allulose as a raw material according to claim 4, characterized in that: The cooling and forming time in S8 is 30-60 minutes. After cooling, the core temperature of the jelly drops to 20-25°C before subsequent storage. The storage environment temperature is 5-25°C and the relative humidity is ≤65%.

9. A method for preparing jelly using D-allulose as a raw material according to claim 4, characterized in that: The jelly has a pH value ≤ 4.6, which is achieved by adjusting gluconate-δ-lactone; the shelf life is 6-12 months under the storage conditions described in claim 8, which is guaranteed by the preservative effect of potassium sorbate.