A low-fat cheese containing a cereal ferment and a method for its preparation

Abstract

The application provides a low-fat cheese containing grain fermentation and a preparation method thereof. The steps include: mixing raw materials, uniformly mixing low-fat protein raw materials, a composite fat substitute and modified spirulina polysaccharide, and grain fermentation, adjusting pH to 6.5-6.7; adding a composite enzyme coagulating agent to coagulate milk; cutting the coagulated milk block, then gradiently increasing temperature to drain whey, filtering and separating 60%-70% whey; squeezing the coagulated milk block; and through early maturation, pulse electric field maturation and late maturation, the finished product is prepared. Through the combined technology of adding modified spirulina polysaccharide and grain fermentation, optimizing coagulation-whey draining process parameters and synergistic effect of pulse electric field maturation, the dual improvement of sensory quality and processing stability of the low-fat cheese containing grain fermentation is realized, and the technical effects of rich flavor, compact organization and smooth taste are achieved.

Description

Technical Field

[0001] This invention relates to the field of food processing technology, specifically to a low-fat cheese containing grain fermentation products and its preparation method. Background Technology

[0002] With the popularization of healthy eating concepts, the market demand for low-fat dairy products continues to grow. Low-fat cheese, due to its combination of nutrition and low fat, has become a research and development hotspot in the dairy industry. However, in the traditional low-fat cheese production process, reducing the fat content can disrupt the network structure of the cheese matrix, resulting in technical defects such as loose and porous texture, severe whey separation, bland and unbalanced flavor, and rough and sticky texture, making it difficult to meet consumers' demand for high-quality low-fat cheese.

[0003] In existing technologies, cheese texture is often improved by adding a single colloid or by adding flavorings to compensate for insufficient flavor. However, the structural support of a single colloid is limited and cannot fundamentally optimize the cheese matrix. The addition of artificial flavorings can easily lead to a single flavor profile and poor harmony, and also poses food safety risks. At the same time, traditional curdling and whey removal processes use crude parameters and lack precise control, which can easily cause uneven cross-linking of casein micelles, further exacerbating the deterioration of cheese texture and taste. Conventional mature processes are time-consuming, inefficient, and difficult to achieve uniform accumulation and stable retention of flavor substances.

[0004] Therefore, developing a preparation technology that can synergistically improve the flavor, texture, and mouthfeel of low-fat cheese, and breaking through the technical bottlenecks of traditional low-fat cheese, has become a key issue that urgently needs to be addressed in the current low-fat cheese industry. Summary of the Invention

[0005] Technical problem to be solved: In view of the above-mentioned technical problems, the purpose of this invention is to provide a low-fat cheese containing grain fermentation products and its preparation method. By adding modified spirulina polysaccharide and lactic acid bacteria fermented rice bran extract, optimizing the curd-whey drainage process parameters, and combining pulsed electric field maturation synergistic enhancement technology, the sensory quality and processing stability of the low-fat cheese containing grain fermentation products are improved, so that the low-fat cheese achieves the technical effect of rich flavor, dense texture and smooth taste.

[0006] Technical solution: A method for preparing low-fat cheese containing grain fermentation products, comprising the following steps: (a) Raw material mixing: Mix the low-fat protein raw material and the complex fat substitute to obtain the base material, add modified spirulina polysaccharide and grain fermentation product, stir at 100-150 r / min for 15 min, add calcium chloride solution, stir evenly, and adjust the pH to 6.5-6.7 with 1 mol / L hydrochloric acid or sodium hydroxide. (ii) Curdling: Add compound enzyme curdling agent, stir at 50-60 r / min for 5-7 min, heat to 32-34℃, keep stirring at 50-60 r / min, keep warm for 40-50 min until a uniform curd block is formed; (iii) Cutting: Cut the curd block into cubes, keeping the blade flat during the cutting process to avoid the curd block from breaking. Let it stand for 10 minutes to allow the surface of the curd block to initially solidify. (iv) Whey drainage: A gradient temperature increase method is used for processing. First stage: Keep warm at 38℃ for 5 minutes, slowly increasing the internal temperature of the curd block; Second stage: Keep warm at 39℃ for 10 minutes to promote whey separation from the superficial layer of the curd network; Third stage: Keep warm at 40℃ for 15 minutes to accelerate the removal of deep whey from the curd network; Whey separation: 60%-70% of the whey is removed by filtration using an inclined filter screen, and the curd is collected after the whey is removed; (v) Pressing: Pressing: Fill the mold (with breathable gauze lining the inner wall) evenly with the whey-drained curd blocks, place it in a hydraulic press, apply a pressure of 0.2-0.3 MPa at 25-28℃, and press for 2-3 hours; during the pressing process, release the pressure for 1 minute every 30 minutes to remove residual air in the mold, ensure uniform density of the curd blocks, and obtain the pressed curd blocks. (vi) Maturity: Early maturation stage: Transfer the pressed curd blocks to the maturation room and let them stand for 10 days at 8-10℃ and 85%-90% relative humidity. During this period, turn them over every 5 days to avoid local moisture accumulation in the curd blocks. Pulsed electric field maturation: The curd block is transferred to a high-voltage pulsed electric field solid processing chamber for further processing; Late maturation: Mature for 5-10 days at 8-10℃ and 85%-90% relative humidity until a uniform maturation layer forms on the surface of the cheese and there is no hard core inside, thus obtaining low-fat cheese containing grain fermentation products.

[0007] Furthermore, the mass ratio of the low-fat protein raw material and the complex fat substitute mentioned in step (i) is 7:3-8:2; the low-fat protein raw material is a mixture of low-fat milk protein (milk fat ≤1.5%) and plant protein in a ratio of (8:2)-(9:1); the complex fat substitute is a mixture of octenyl succinic anhydride modified inulin and monoglyceride.

[0008] Furthermore, the plant protein is soy protein isolate with a gel strength ≥150 g.

[0009] Furthermore, the mass ratio of the octenyl succinic anhydride modified inulin to monoglyceride is 6:1-7:1.

[0010] Furthermore, in step (i), the amount of modified spirulina polysaccharide added is 0.1%-0.2% of the total mass of the base material; the amount of grain fermentation product added is 0.5%-0.8% of the total mass of the base material; the concentration of the calcium chloride solution is 0.5-1.0 mol / L, and the amount added is 0.02%-0.03% of the total mass of the base material.

[0011] Furthermore, the preparation method of the modified spirulina polysaccharide mentioned in step (i) is as follows:

[0012] S1. Solution preparation: Take Spirulina polysaccharide powder with a purity of ≥95%, dissolve it in deionized water, and prepare a solution with a mass concentration of 1-2%. S2. Alkali denaturation treatment: Adjust the pH of the solution to 9.0-10.0, stir at room temperature for 30-60 min to dissociate the polysaccharide molecular chains into a single-chain random coil conformation; S3. Conformation-induced refolding: Under ultrasonic conditions, the pH was slowly adjusted to 6.5-7.0, and ultrasonic treatment was performed simultaneously. The ultrasonic power was 360 W, the ultrasonic frequency was 40 kHz, the treatment time was 20 min, and the temperature was controlled at 25℃. S4. Stabilization treatment: After sonication, continue stirring for 20-40 min to allow the polysaccharide molecular chains to reassemble into an ordered helical conformation; S5. Drying: Modified spirulina polysaccharide is obtained by freeze-drying or spray drying.

[0013] Furthermore, in step (a), the grain fermentation product is a lactic acid bacteria fermented rice bran extract, prepared by: S1. Rice bran pretreatment: Take fresh rice bran, crush it (particle size ≤ 0.15 mm), mix it with deionized water at a mass ratio of 1:5, gelatinize it in a 95℃ water bath for 30 min, and cool it to 30℃ to obtain rice bran paste. S2. Fermentation process: Inoculate with activated Lactobacillus plantarum culture and anaerobic ferment in a 30℃ constant temperature fermenter for 44-48 hours; S3. Extract purification: The fermentation broth is centrifuged at 8000-9000 r / min for 15 min to remove residue. The supernatant is filtered through a 0.22 μm microfiltration membrane, and the collected filtrate is the lactic acid bacteria fermented rice bran extract.

[0014] Furthermore, the concentration of the *Lactobacillus plantarum* bacterial solution in S2 is 10. 8 CFU / mL, inoculation amount is 3%-5% of the mass of rice bran paste.

[0015] Furthermore, the compound enzyme coagulant mentioned in step (ii) is abomasal enzyme and microbial rennet in a mass ratio of (3-4):(2-3), and the amount added is 0.002%-0.003% of the total mass of the base material.

[0016] Furthermore, the cube described in step (iii) has a size of 1 cm × 1 cm × 1 cm.

[0017] Furthermore, the pore size of the inclined filter screen is 0.5 mm.

[0018] Furthermore, the processing conditions described in step (vi) are: electric field strength 5-10 kV / cm, intermittent processing, total cumulative processing time of 10 min, temperature 8-10℃, relative humidity 85%-90%. The pulsed electric field can promote the redistribution of moisture inside the cheese and improve the texture uniformity.

[0019] The present invention also provides a low-fat cheese containing grain fermentation product prepared by the above method.

[0020] Beneficial effects: 1. This invention utilizes the active groups such as hydroxyl groups on the modified spirulina polysaccharide molecular chain to form hydrogen bonds and ionic bonds with casein micelles, constructing a dense and elastic three-dimensional spatial network structure in the cheese matrix. This achieves the effects of improving the texture of low-fat cheese containing grain fermentation products, inhibiting whey precipitation, and enhancing texture uniformity and stability. At the same time, the modified spirulina polysaccharide can adsorb free water in the cheese system, reduce the water activity of the system, and avoid the defects of loose matrix structure caused by reduced fat content. This further enhances the smoothness of the cheese cut surface, eliminates hard cores and pores, and improves product formability. 2. This invention utilizes the small molecule peptides, free amino acids, vitamins, and flavor precursors contained in fermented rice bran extract to provide sufficient nutrient substrates for Lactobacillus, Streptococcus, and other strains during cheese fermentation. This activates the metabolic activity of the strains and directionally induces the synthesis and accumulation of characteristic cheese aroma substances such as ethyl acetate, 3-hydroxy-2-butanone, and 2,3-butanediol. This results in a rich and pure milky aroma in cheese and mitigates the blandness of low-fat products. Simultaneously, the active ingredients in the fermented rice bran extract can inhibit the formation of undesirable metabolites such as bitter peptides and rancid substances during cheese processing, thereby eliminating bitterness, rancidity, and other off-flavors and improving flavor harmony and purity. 3. This invention precisely controls the cross-linking rate and degree of casein micelles by matching the amount of rennet with the coagulation temperature and time. This avoids problems such as rough texture and high porosity caused by excessively rapid coagulation, or loose texture and incomplete whey separation caused by excessively slow coagulation. This achieves the effect of optimizing the initial texture of cheese and laying a uniform and stable matrix foundation for subsequent maturation. In addition, it combines gradient heating with whey removal. By gradually increasing the whey removal temperature and extending the holding time at each stage, it avoids the damage to the matrix structure and aggregation of casein particles caused by rapid whey removal. This achieves the effect of further densifying the texture, improving the elasticity and toughness of cheese, and enhancing the textural stability of the product. 4. This invention utilizes a non-thermal physical modification synergistic enhancement technology matured by pulsed electric field. By leveraging the electroporation effect and charge rearrangement of high-voltage short pulses, it induces controllable depolymerization and partial unfolding of casein micelles in the cheese matrix, exposing more active binding sites. This promotes the directional cross-linking and uniform distribution of casein molecules and functional additive molecules, strengthens intermolecular forces such as hydrophobic interactions, hydrogen bonds, and disulfide bonds, and constructs a denser and more uniform three-dimensional network structure. This significantly improves the smoothness of the cheese's texture, reduces stickiness and eliminates the sticky feeling, reduces graininess and roughness, and enhances overall palatability. Simultaneously, the pulsed electric field activates the activity of endogenous proteases during the maturation process, accelerates the generation and transformation of flavor precursors, and promotes the rapid diffusion and uniform distribution of flavor substances within the matrix. This effectively shortens the formation and equilibrium cycle of flavor substances, significantly reducing product maturation time, reducing undesirable flavors such as bitterness and astringency, and improving the flavor stability and batch consistency of the cheese. Attached Figure Description

[0021] Figure 1 GC-MS image of key aroma components of the low-fat cheese prepared in Example 10; Figure 2 GC-MS image of key aroma components of the low-fat cheese prepared in Example 16; Figure 3 GC-MS image of key aroma components of the low-fat cheese prepared in Comparative Example 4; Figure 4 GC-MS image of key aroma components in the low-fat cheese prepared in Comparative Example 6; Figure 5 GC-MS image of key aroma components of the low-fat cheese prepared in Comparative Example 8; Figure 6 GC-MS diagram of key aroma components in the low-fat cheese prepared in Comparative Example 10; Figure 7 GC-MS image of key aroma components of the low-fat cheese prepared in Comparative Example 12; Figure 8These are photographic comparisons of low-fat cheese prepared in some of the embodiments and comparative examples. Detailed Implementation

[0022] This invention proposes a low-fat cheese containing fermented grains 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.

[0023] Low-fat raw milk, with a milk fat content of ≤1.5%; Spirulina polysaccharide powder purity ≥ 95%; Lactobacillus plantarum was purchased from Beijing Baocang Biotechnology Co., Ltd., strain number: CICC 20265, and cultured to a bacterial concentration of 10. 8 CFU / mL.

[0024] Example 1 The preparation method of octenyl succinic anhydride modified inulin includes the following steps: Step 1: Place the inulin in a vacuum drying oven at 60℃ for 2 hours to remove surface free moisture until the inulin moisture content is 5%, then cool. Step 2: Place 100 parts by weight of dried inulin in a high-speed mixer, turn on the stirrer (300 r / min), slowly add 2 parts by weight of octenyl succinic anhydride, and mix for 5 min; then add 0.8 parts by weight of sodium bicarbonate and continue mixing for 3 min. Step 3: Raise the mixer temperature to 75℃, maintain the rotation speed at 300 r / min, and react at a constant temperature for 3 h; Step 4: After the reaction is complete, lower the system temperature to 35°C, add citric acid to adjust the pH of the system to 6.5, and terminate the esterification reaction; Step 5: Place the reaction product in an 80℃ hot air drying oven and dry it to constant weight. After pulverizing, pass it through a 100-mesh sieve to obtain octenyl succinic anhydride modified inulin.

[0025] Example 2 The compound fatty acid substitute is a mixture of octenyl succinic anhydride modified inulin and monoglyceride, with a mass ratio of 6.5:1.

[0026] Example 3 The low-fat protein ingredient is a blend of low-fat raw milk and soy protein isolate in an 8:2 ratio.

[0027] Example 4 The low-fat protein ingredient is a blend of low-fat raw milk and soy protein isolate in a 9:1 ratio.

[0028] Example 5 The preparation method of modified spirulina polysaccharide is as follows: (1) Preparation of solution: Take spirulina polysaccharide powder, dissolve it in deionized water, and prepare a solution with a mass concentration of 1%; (2) Alkali denaturation treatment: Adjust the pH of the solution to 9 and stir at room temperature for 30 min to dissociate the polysaccharide molecular chains into single-chain random coil conformations; (3) Conformation-induced refolding: Under ultrasonic conditions, the pH was slowly adjusted to 6.5, and ultrasonic treatment was performed at the same time. The ultrasonic power was 360W, the ultrasonic frequency was 40 kHz, the treatment time was 20 min, and the temperature was controlled at 25℃. (4) Stabilization treatment: After sonication, continue stirring for 20 min to allow the polysaccharide molecular chains to reassemble into an ordered helical conformation; (5) Drying: Modified spirulina polysaccharide is obtained by freeze drying or spray drying.

[0029] Example 6 The preparation method of modified spirulina polysaccharide is as follows: (1) Preparation of solution: Take spirulina polysaccharide powder, dissolve it in deionized water, and prepare a solution with a mass concentration of 2%; (2) Alkali denaturation treatment: Adjust the pH of the solution to 10 and stir at room temperature for 60 min to dissociate the polysaccharide molecular chains into a single-chain random coil conformation; (3) Conformation-induced refolding: Under ultrasonic conditions, the pH was slowly adjusted to 7.0, and ultrasonic treatment was performed at the same time. The ultrasonic power was 360W, the ultrasonic frequency was 40 kHz, the treatment time was 20 min, and the temperature was controlled at 25℃. (4) Stabilization treatment: After sonication, continue stirring for 40 min to allow the polysaccharide molecular chains to reassemble into an ordered helical conformation; (5) Drying: Modified spirulina polysaccharide is obtained by freeze drying or spray drying.

[0030] Example 7 The preparation method of lactic acid bacteria fermented rice bran extract is as follows: S1. Rice bran pretreatment: Take fresh rice bran, crush it (particle size ≤ 0.15 mm), mix it with deionized water at a mass ratio of 1:5, gelatinize it in a 95℃ water bath for 30 min, and cool it to 30℃ to obtain rice bran paste. S2. Fermentation process: Inoculate with 3% of the activated rice bran paste by weight of Lactobacillus plantarum culture, and anaerobic ferment in a 30℃ constant temperature fermenter for 48 h; S3. Extract purification: The fermentation broth was centrifuged at 8500 r / min for 15 min to remove the residue. The supernatant was filtered through a 0.22 μm microfiltration membrane, and the collected filtrate was the lactic acid bacteria fermented rice bran extract.

[0031] Example 8 The preparation method of lactic acid bacteria fermented rice bran extract is as follows: S1. Rice bran pretreatment: Take fresh rice bran, crush it (particle size ≤ 0.15 mm), mix it with deionized water at a mass ratio of 1:5, gelatinize it in a 95℃ water bath for 30 min, and cool it to 30℃ to obtain rice bran paste. S2. Fermentation process: Inoculate with 5% of the activated rice bran paste by weight of Lactobacillus plantarum culture, and anaerobic ferment in a 30℃ constant temperature fermenter for 48 h; S3. Extract purification: The fermentation broth was centrifuged at 9000 r / min for 15 min to remove the residue. The supernatant was filtered through a 0.22 μm microfiltration membrane, and the collected filtrate was the lactic acid bacteria fermented rice bran extract.

[0032] Example 9 A method for preparing low-fat cheese containing fermented grains includes the following steps: (a) Raw material mixing: The low-fat protein raw material prepared in Example 3 and the composite fat substitute prepared in Example 2 were mixed in a mass ratio of 7:3 to obtain the base material. 0.1% of the modified spirulina polysaccharide prepared in Example 5 and 0.5% of the lactic acid bacteria fermented rice bran extract prepared in Example 7 were added to the base material. The mixture was stirred at 100 r / min for 15 min. 0.02% of the total mass of the base material and a calcium chloride solution with a concentration of 0.5 mol / L were added and stirred evenly. The pH was adjusted to 6.5 with 1 mol / L hydrochloric acid or sodium hydroxide. (ii) Curdling: Add 0.002% of the total mass of the base material of compound enzyme curdling agent (abomasal enzyme and microbial curdling enzyme in a mass ratio of 3:2), stir at 50 r / min for 5 min, heat to 32℃, keep stirring at 50 r / min, and keep warm for 40 min until a uniform curd block is formed. (iii) Cutting: Cut the curd block into 1 cm × 1 cm × 1 cm cubes. Keep the blade flat during the cutting process to avoid the curd block from breaking. Let it stand for 10 minutes to allow the surface of the curd block to initially solidify. (iv) Whey drainage: A gradient temperature increase method is used for processing. First stage: Keep warm at 38℃ for 5 minutes; Second stage: Keep warm at 39℃ for 10 minutes; Third stage: Keep warm at 40℃ for 15 minutes; Whey separation: 60% of the whey is removed by filtration using an inclined filter screen (0.5 mm pore size), and the curd is collected after whey removal; (v) Pressing: Pressing: The curd blocks after whey removal are evenly filled into the mold (with breathable gauze lining the inner wall), placed in a hydraulic press, and pressed for 2 hours at 25°C with a pressure of 0.2 MPa. During the pressing process, the pressure is released for 1 minute every 30 minutes to remove residual air from the mold and ensure that the density of the curd blocks is uniform, thus obtaining the pressed curd blocks. (vi) Maturity: Early maturation stage: Transfer the pressed curd blocks to the maturation room and let them stand for 10 days at 8℃ and 85% relative humidity. During this period, turn them over every 5 days to prevent local moisture accumulation in the curd blocks. Pulsed electric field maturation: The coagulated block was transferred to a high-voltage pulsed electric field solid treatment chamber for treatment. The electric field strength was 5 kV / cm. Intermittent treatment was used, with each pulse treatment lasting 30 seconds followed by a 30-second interval. The total cumulative treatment time was 10 minutes. The temperature was 9℃ and the relative humidity was 85%. Late maturation: Mature for 5 days at 8℃ and 85% relative humidity until a uniform maturation layer forms on the surface of the cheese and there is no hard core inside, thus obtaining low-fat cheese containing grain fermentation products.

[0033] Example 10 A method for preparing low-fat cheese containing fermented grains includes the following steps: (a) Raw material mixing: The low-fat protein raw material prepared in Example 3 with a mass ratio of 7.2:2.8 and the composite fat substitute prepared in Example 2 were mixed to obtain the base material. 0.12% of the total mass of the base material was added to the modified spirulina polysaccharide prepared in Example 5 and 0.55% of the lactic acid bacteria fermented rice bran extract prepared in Example 7. The mixture was stirred at 110 r / min for 15 min. 0.022% of the total mass of the base material was added to the calcium chloride solution with a concentration of 0.6 mol / L. The mixture was stirred evenly and the pH was adjusted to 6.5 with 1 mol / L hydrochloric acid or sodium hydroxide. (ii) Curdling: Add 0.0022% of the total mass of the base material of compound enzyme curdling agent (abomasal enzyme and microbial curdling enzyme in a mass ratio of 3:2), stir at 52 r / min for 5 min, heat to 32.5℃, keep stirring at 52 r / min, and keep warm for 42 min until a uniform curd block is formed. (iii) Cutting: Cut the curd block into 1 cm × 1 cm × 1 cm cubes. Keep the blade flat during the cutting process to avoid the curd block from breaking. Let it stand for 10 minutes to allow the surface of the curd block to initially solidify. (iv) Whey drainage: A gradient temperature increase method is used for processing. First stage: Keep warm at 38℃ for 5 minutes; Second stage: Keep warm at 39℃ for 10 minutes; Third stage: Keep warm at 40℃ for 15 minutes; Whey separation: 62% of the whey is removed by filtration using an inclined filter screen (0.5 mm pore size), and the curd is collected after whey removal; (v) Pressing: Pressing: The curd blocks after whey removal are evenly filled into the mold (with the inner wall lined with breathable gauze), placed in a hydraulic press, and pressed at 0.22 MPa at 26℃ for 2.2 h; during the pressing process, the pressure is released for 1 min every 30 min to remove residual air in the mold and ensure that the density of the curd blocks is uniform, thus obtaining the pressed curd blocks. (vi) Maturity: Early maturation stage: Transfer the pressed curd blocks to the maturation room and let them stand for 10 days at 8.5℃ and 86% relative humidity. During this period, turn them over every 5 days to avoid local moisture accumulation in the curd blocks. Pulsed electric field maturation: The curd block was transferred to a high-voltage pulsed electric field solid treatment chamber for treatment. The electric field strength was 6 kV / cm. Intermittent treatment was used, with each pulse treatment lasting 30 seconds followed by a 30-second interval. The total cumulative treatment time was 10 minutes. The temperature was 9℃ and the relative humidity was 86%. Late maturation: Mature for 6 days at 8.5℃ and 86% relative humidity until a uniform maturation layer forms on the surface of the cheese and there is no hard core inside, thus obtaining low-fat cheese containing grain fermentation products.

[0034] Example 11 A method for preparing low-fat cheese containing fermented grains includes the following steps: (a) Raw material mixing: The low-fat protein raw material prepared in Example 4 with a mass ratio of 7.4:2.6 and the composite fat substitute prepared in Example 2 were mixed to obtain the base material. 0.14% of the modified spirulina polysaccharide prepared in Example 6 and 0.6% of the lactic acid bacteria fermented rice bran extract prepared in Example 8 were added to the base material. The mixture was stirred at 120 r / min for 15 min. 0.024% of the total mass of the base material and a calcium chloride solution with a concentration of 0.7 mol / L were added and stirred evenly. The pH was adjusted to 6.6 with 1 mol / L hydrochloric acid or sodium hydroxide. (ii) Curdling: Add 0.0024% of the total mass of the base material of compound enzyme curdling agent (abomalacin and microbial curdling enzyme in a mass ratio of 3.2:2.3), stir at 54 r / min for 6 min, heat to 33℃, keep stirring at 54 r / min, and keep warm for 44 min until a uniform curd block is formed. (iii) Cutting: Cut the curd block into 1cm×1cm×1cm cubes. Keep the blade flat during the cutting process to avoid the curd block from breaking. Let it stand for 10 minutes to allow the surface of the curd block to initially solidify. (iv) Whey drainage: A gradient temperature increase method is used for processing. First stage: Keep warm at 38℃ for 5 minutes; Second stage: Keep warm at 39℃ for 10 minutes; Third stage: Keep warm at 40℃ for 15 minutes; Whey separation: 64% of the whey is removed by filtration using an inclined filter screen (0.5mm pore size), and the curd is collected after whey removal; (v) Pressing: Pressing: The curd blocks after whey removal are evenly filled into the mold (with the inner wall lined with breathable gauze), placed in a hydraulic press, and pressed at 0.24 MPa at 26℃ for 2.4 h; during the pressing process, the pressure is released for 1 min every 30 min to remove residual air in the mold and ensure that the density of the curd blocks is uniform, thus obtaining the pressed curd blocks. (vi) Maturity: Early maturation stage: Transfer the pressed curd blocks to the maturation room and let them stand for 10 days at 9°C and 87% relative humidity. During this period, turn them over every 5 days to prevent local moisture accumulation in the curd blocks. Pulsed electric field maturation: The curd block was transferred to a high-voltage pulsed electric field solid treatment chamber for treatment. The electric field strength was 7 kV / cm. Intermittent treatment was used, with each pulse treatment lasting 30 seconds followed by a 30-second interval. The total cumulative treatment time was 10 minutes. The temperature was 9℃ and the relative humidity was 87%. Late maturation: Mature for 7 days at 9℃ and 87% relative humidity until a uniform maturation layer forms on the surface of the cheese and there is no hard core inside, thus obtaining low-fat cheese containing grain fermentation products.

[0035] Example 12 A method for preparing low-fat cheese containing fermented grains includes the following steps: (a) Raw material mixing: The low-fat protein raw material prepared in Example 3 with a mass ratio of 7.5:2.5 and the composite fat substitute prepared in Example 2 are mixed to obtain the base material. 0.15% of the modified spirulina polysaccharide prepared in Example 5 and 0.65% of the lactic acid bacteria fermented rice bran extract prepared in Example 7 are added to the base material. The mixture is stirred at 125 r / min for 15 min. 0.025% of the total mass of the base material and a calcium chloride solution with a concentration of 0.75 mol / L are added and stirred evenly. The pH is adjusted to 6.6 with 1 mol / L hydrochloric acid or sodium hydroxide. (ii) Curdling: Add 0.0025% of the total mass of the base material of compound enzyme curdling agent (abomalacin and microbial curdling enzyme in a mass ratio of 3.5:2.5), stir at 55 r / min for 6 min, heat to 33℃, keep stirring at 55 r / min, and keep warm for 45 min until a uniform curd block is formed. (iii) Cutting: Cut the curd block into 1 cm × 1 cm × 1 cm cubes. Keep the blade flat during the cutting process to avoid the curd block from breaking. Let it stand for 10 minutes to allow the surface of the curd block to initially solidify. (iv) Whey drainage: A gradient temperature increase method is used for processing. First stage: Keep warm at 38℃ for 5 minutes, slowly increase the internal temperature of the curd block; Second stage: Keep warm at 39℃ for 10 min to promote whey separation from the superficial layer of the curd network; Third stage: Keep warm at 40℃ for 15 minutes to accelerate the removal of deep whey from the curd network; Whey separation: 65% of the whey is removed by filtration using an inclined filter screen (0.5 mm pore size), and the curd is collected after whey removal; (v) Pressing: Pressing: The curd blocks after whey removal are evenly filled into the mold (with the inner wall lined with breathable gauze), placed in a hydraulic press, and pressed at 0.25 MPa at 27°C for 2.5 h; during the pressing process, the pressure is released for 1 min every 30 min to remove residual air in the mold and ensure that the density of the curd blocks is uniform, thus obtaining the pressed curd blocks. (vi) Maturity: Early maturation stage: Transfer the pressed curd blocks to the maturation room and let them stand for 10 days at 9°C and 88% relative humidity. During this period, turn them over every 5 days to prevent local moisture accumulation in the curd blocks. Pulsed electric field maturation: The curd block was transferred to a high-voltage pulsed electric field solid treatment chamber for treatment. The electric field strength was 7.5 kV / cm. Intermittent treatment was used, with each pulse treatment lasting 30 seconds followed by a 30-second interval. The total cumulative treatment time was 10 minutes. The temperature was 9℃ and the relative humidity was 88%. Late maturation: Mature for 8 days at 9℃ and 88% relative humidity until a uniform maturation layer forms on the surface of the cheese and there is no hard core inside, thus obtaining low-fat cheese containing grain fermentation products.

[0036] Example 13 A method for preparing low-fat cheese containing fermented grains includes the following steps: (a) Raw material mixing: The low-fat protein raw material prepared in Example 4 with a mass ratio of 7.6:2.4 and the composite fat substitute prepared in Example 2 were mixed to obtain the base material. 0.16% of the modified spirulina polysaccharide prepared in Example 6 and 0.7% of the lactic acid bacteria fermented rice bran extract prepared in Example 8 were added to the base material. The mixture was stirred at 130 r / min for 15 min. 0.026% of the total mass of the base material and a calcium chloride solution with a concentration of 0.8 mol / L were added and stirred evenly. The pH was adjusted to 6.6 with 1 mol / L hydrochloric acid or sodium hydroxide. (ii) Curdling: Add 0.0026% of the total mass of the base material of the compound enzyme curdling agent (abomalacia and microbial curdling enzyme in a mass ratio of 3.6:2.6), stir at 56 r / min for 6 min, heat to 33.5℃, keep stirring at 56 r / min, and keep warm for 46 min until a uniform curd block is formed. (iii) Cutting: Cut the curd block into 1 cm × 1 cm × 1 cm cubes. Keep the blade flat during the cutting process to avoid the curd block from breaking. Let it stand for 10 minutes to allow the surface of the curd block to initially solidify. (iv) Whey drainage: A gradient temperature increase method is used for processing. First stage: Keep warm at 38℃ for 5 minutes, slowly increase the internal temperature of the curd block; Second stage: Keep warm at 39℃ for 10 min to promote whey separation from the superficial layer of the curd network; Third stage: Keep warm at 40℃ for 15 minutes to accelerate the removal of deep whey from the curd network; Whey separation: 66% of the whey is removed by filtration using an inclined filter screen (0.5 mm pore size), and the curd is collected after whey removal; (v) Pressing: Pressing: The curd blocks after whey removal are evenly filled into the mold (with the inner wall lined with breathable gauze), placed in a hydraulic press, and pressed at 0.26 MPa at 27°C for 2.6 h; during the pressing process, the pressure is released for 1 min every 30 min to remove residual air in the mold and ensure that the density of the curd blocks is uniform, thus obtaining the pressed curd blocks. (vi) Maturity: Early maturation stage: Transfer the pressed curd blocks to the maturation room and let them stand for 10 days at 9.5℃ and 88% relative humidity. During this period, turn them over every 5 days to prevent local moisture accumulation in the curd blocks. Pulsed electric field maturation: The curd block was transferred to a high-voltage pulsed electric field solid treatment chamber for treatment. The electric field strength was 8 kV / cm. Intermittent treatment was used, with each pulse treatment lasting 30 seconds followed by a 30-second interval. The total cumulative treatment time was 10 minutes. The temperature was 9.5℃ and the relative humidity was 88%. Late maturation: Mature for 8 days at 9.5℃ and 88% relative humidity until a uniform maturation layer forms on the surface of the cheese and there is no hard core inside, thus obtaining low-fat cheese containing grain fermentation products.

[0037] Example 14 A method for preparing low-fat cheese containing fermented grains includes the following steps: (a) Raw material mixing: The low-fat protein raw material prepared in Example 3 with a mass ratio of 7.7:2.3 and the composite fat substitute prepared in Example 2 were mixed to obtain the base material. 0.17% of the modified spirulina polysaccharide prepared in Example 5 and 0.72% of the lactic acid bacteria fermented rice bran extract prepared in Example 7 were added to the base material. The mixture was stirred at 135 r / min for 15 min. 0.027% of the total mass of the base material and a calcium chloride solution with a concentration of 0.85 mol / L were added and stirred evenly. The pH was adjusted to 6.7 with 1 mol / L hydrochloric acid or sodium hydroxide. (ii) Curdling: Add 0.0027% of the total mass of the base material of compound enzyme curdling agent (abomasal enzyme and microbial curdling enzyme in a mass ratio of 3.7:2.7), stir at 57 r / min for 7 min, heat to 33.5℃, keep stirring at 57 r / min, and keep warm for 47 min until a uniform curd block is formed. (iii) Cutting: Cut the curd block into 1 cm × 1 cm × 1 cm cubes. Keep the blade flat during the cutting process to avoid the curd block from breaking. Let it stand for 10 minutes to allow the surface of the curd block to initially solidify. (iv) Whey drainage: A gradient temperature increase method is used for processing. First stage: Keep warm at 38℃ for 5 minutes, slowly increase the internal temperature of the curd block; Second stage: Keep warm at 39℃ for 10 min to promote whey separation from the superficial layer of the curd network; Third stage: Keep warm at 40℃ for 15 minutes to accelerate the removal of deep whey from the curd network; Whey separation: 67% of the whey is removed by filtration using an inclined filter screen (0.5 mm pore size), and the curd is collected after whey removal; (v) Pressing: Pressing: The curd blocks after whey removal are evenly filled into the mold (with the inner wall lined with breathable gauze), placed in a hydraulic press, and pressed at 0.27 MPa at 27°C for 2.7 h; during the pressing process, the pressure is released for 1 min every 30 min to remove residual air in the mold and ensure that the density of the curd blocks is uniform, thus obtaining the pressed curd blocks. (vi) Maturity: Early maturation stage: Transfer the pressed curd blocks to the maturation room and let them stand for 10 days at 9.5℃ and 89% relative humidity. During this period, turn them over every 5 days to prevent local moisture accumulation in the curd blocks. Pulsed electric field maturation: The curd block was transferred to a high-voltage pulsed electric field solid treatment chamber for treatment. The electric field strength was 8.5 kV / cm. Intermittent treatment was used, with each pulse treatment lasting 30 seconds followed by a 30-second interval, for a total cumulative treatment time of 10 minutes. The temperature was 9.5℃ and the relative humidity was 89%. Late maturation: Mature for 9 days at 9.5℃ and 89% relative humidity until a uniform maturation layer forms on the surface of the cheese and there is no hard core inside, thus obtaining low-fat cheese containing grain fermentation products.

[0038] Example 15 A method for preparing low-fat cheese containing fermented grains includes the following steps: (a) Raw material mixing: The low-fat protein raw material prepared in Example 4 with a mass ratio of 7.8:2.2 and the composite fat substitute prepared in Example 2 were mixed to obtain the base material. 0.18% of the modified spirulina polysaccharide prepared in Example 6 and 0.75% of the lactic acid bacteria fermented rice bran extract prepared in Example 8 were added to the base material. The mixture was stirred at 140 r / min for 15 min. 0.028% of the total mass of the base material and a calcium chloride solution with a concentration of 0.9 mol / L were added and stirred evenly. The pH was adjusted to 6.7 with 1 mol / L hydrochloric acid or sodium hydroxide. (ii) Curdling: Add 0.0028% of the total mass of the base material of the compound enzyme curdling agent (abomasal ratio of 3.8:2.8 of abomasal enzyme and microbial curdling enzyme), stir at 58 r / min for 7 min, heat to 34℃, keep stirring at 58 r / min, and keep warm for 48 min until a uniform curd block is formed. (iii) Cutting: Cut the curd block into 1 cm × 1 cm × 1 cm cubes. Keep the blade flat during the cutting process to avoid the curd block from breaking. Let it stand for 10 minutes to allow the surface of the curd block to initially solidify. (iv) Whey drainage: A gradient temperature increase method is used for processing. First stage: Keep warm at 38℃ for 5 minutes, slowly increase the internal temperature of the curd block; Second stage: Keep warm at 39℃ for 10 min to promote whey separation from the superficial layer of the curd network; Third stage: Keep warm at 40℃ for 15 minutes to accelerate the removal of deep whey from the curd network; Whey separation: 68% of the whey is removed by filtration using an inclined filter screen (0.5 mm pore size), and the curd is collected after whey removal; (v) Pressing: Pressing: The curd blocks after whey removal are evenly filled into the mold (with the inner wall lined with breathable gauze), placed in a hydraulic press, and pressed at 0.28 MPa at 28℃ for 2.8 h; during the pressing process, the pressure is released for 1 min every 30 min to remove residual air in the mold and ensure that the density of the curd blocks is uniform, thus obtaining the pressed curd blocks. (vi) Maturity: Early maturation stage: Transfer the pressed curd blocks to the maturation room and let them stand for 10 days at 10℃ and 89% relative humidity. During this period, turn them over every 5 days to prevent local moisture accumulation in the curd blocks. Pulsed electric field maturation: The curd block was transferred to a high-voltage pulsed electric field solid treatment chamber for treatment. The electric field strength was 9 kV / cm. Intermittent treatment was used, with each pulse treatment lasting 30 seconds followed by a 30-second interval. The total cumulative treatment time was 10 min. The temperature was 10℃ and the relative humidity was 89%. Late maturation: Mature for 9 days at 10℃ and 89% relative humidity until a uniform maturation layer forms on the surface of the cheese and there is no hard core inside, thus obtaining low-fat cheese containing grain fermentation products.

[0039] Example 16 A method for preparing low-fat cheese containing fermented grains includes the following steps: (a) Raw material mixing: The low-fat protein raw material prepared in Example 3 with a mass ratio of 7.9:2.1 and the composite fat substitute prepared in Example 2 were mixed to obtain the base material. 0.19% of the modified spirulina polysaccharide prepared in Example 5 and 0.78% of the lactic acid bacteria fermented rice bran extract prepared in Example 7 were added to the base material. The mixture was stirred at 145 r / min for 15 min. 0.029% of the total mass of the base material and a calcium chloride solution with a concentration of 0.95 mol / L were added and stirred evenly. The pH was adjusted to 6.7 with 1 mol / L hydrochloric acid or sodium hydroxide. (ii) Curdling: Add 0.0029% of the total mass of the base material of the compound enzyme curdling agent (abomasal ratio of 3.9:2.9 of abomasal enzyme and microbial curdling enzyme), stir at 59 r / min for 7 min, heat to 34℃, keep stirring at 59 r / min, and keep warm for 49 min until a uniform curd block is formed. (iii) Cutting: Cut the curd block into 1 cm × 1 cm × 1 cm cubes. Keep the blade flat during the cutting process to avoid the curd block from breaking. Let it stand for 10 minutes to allow the surface of the curd block to initially solidify. (iv) Whey drainage: A gradient temperature increase method is used for processing. First stage: Keep warm at 38℃ for 5 minutes, slowly increase the internal temperature of the curd block; Second stage: Keep warm at 39℃ for 10 min to promote whey separation from the superficial layer of the curd network; Third stage: Keep warm at 40℃ for 15 minutes to accelerate the removal of deep whey from the curd network; Whey separation: 69% of the whey is removed by filtration using an inclined filter screen (0.5 mm pore size), and the curd is collected after whey removal; (v) Pressing: Pressing: The curd blocks after whey removal are evenly filled into the mold (with the inner wall lined with breathable gauze), placed in a hydraulic press, and pressed at 0.29 MPa at 28℃ for 2.9 h; during the pressing process, the pressure is released for 1 min every 30 min to remove residual air in the mold and ensure that the density of the curd blocks is uniform, thus obtaining the pressed curd blocks. (vi) Maturity: Early maturation stage: Transfer the pressed curd blocks to the maturation room and let them stand for 10 days at 10℃ and 90% relative humidity. During this period, turn them over every 5 days to prevent local moisture accumulation in the curd blocks. Pulsed electric field maturation: The curd block was transferred to a high-voltage pulsed electric field solid treatment chamber for treatment. The electric field strength was 9.5 kV / cm. Intermittent treatment was used, with each pulse treatment lasting 30 seconds followed by a 30-second interval, for a total cumulative treatment time of 10 min. The temperature was 10℃ and the relative humidity was 90%. Late maturation: Mature at 10℃ and 90% relative humidity for 10 days until a uniform maturation layer forms on the surface of the cheese and there is no hard core inside, thus obtaining low-fat cheese containing grain fermentation products.

[0040] Example 17 A method for preparing low-fat cheese containing fermented grains includes the following steps: (a) Raw material mixing: The low-fat protein raw material prepared in Example 4 and the composite fat substitute prepared in Example 2 were mixed in a mass ratio of 8:2 to obtain the base material. 0.2% of the modified spirulina polysaccharide prepared in Example 6 and 0.8% of the lactic acid bacteria fermented rice bran extract prepared in Example 8 were added to the base material. The mixture was stirred at 150 r / min for 15 min. 0.03% of the total mass of the base material and a calcium chloride solution with a concentration of 1.0 mol / L were added and stirred evenly. The pH was adjusted to 6.7 with 1 mol / L hydrochloric acid or sodium hydroxide. (ii) Curdling: Add 0.003% of the total mass of the base material of compound enzyme curdling agent (abomalacia and microbial curdling enzyme in a mass ratio of 4:3), stir at 60 r / min for 7 min, heat to 34℃, keep stirring at 60 r / min, and keep warm for 50 min until a uniform curd block is formed. (iii) Cutting: Cut the curd block into 1 cm × 1 cm × 1 cm cubes. Keep the blade flat during the cutting process to avoid the curd block from breaking. Let it stand for 10 minutes to allow the surface of the curd block to initially solidify. (iv) Whey drainage: A gradient temperature increase method is used for processing. First stage: Keep warm at 38℃ for 5 minutes, slowly increase the internal temperature of the curd block; Second stage: Keep warm at 39℃ for 10 min to promote whey separation from the superficial layer of the curd network; Third stage: Keep warm at 40℃ for 15 minutes to accelerate the removal of deep whey from the curd network; Whey separation: 70% of the whey is removed by filtration using an inclined filter screen (0.5 mm pore size), and the curd is collected after whey removal; (v) Pressing: Pressing: The curd blocks after whey removal are evenly filled into the mold (with breathable gauze lining the inner wall), placed in a hydraulic press, and pressed for 3 hours at 28°C with a pressure of 0.3 MPa. During the pressing process, the pressure is released for 1 minute every 30 minutes to remove residual air from the mold and ensure that the density of the curd blocks is uniform, thus obtaining the pressed curd blocks. (vi) Maturity: Early maturation stage: Transfer the pressed curd blocks to the maturation room and let them stand for 10 days at 10℃ and 90% relative humidity. During this period, turn them over every 5 days to prevent local moisture accumulation in the curd blocks. Pulsed electric field maturation: The curd block was transferred to a high-voltage pulsed electric field solid treatment chamber for treatment. The electric field strength was 10 kV / cm. Intermittent treatment was used, with each pulse treatment lasting 30 seconds followed by a 30-second interval. The total cumulative treatment time was 10 min. The temperature was 10℃ and the relative humidity was 90%. Late maturation: Mature at 10℃ and 90% relative humidity for 10 days until a uniform maturation layer forms on the surface of the cheese and there is no hard core inside, thus obtaining low-fat cheese containing grain fermentation products.

[0041] Example 18 A method for preparing low-fat cheese containing fermented grains includes the following steps: (a) Raw material mixing: The low-fat protein raw material prepared in Example 3 with a mass ratio of 7.5:2.5 and the composite fat substitute prepared in Example 2 were mixed to obtain the base material. 0.15% of the modified spirulina polysaccharide prepared in Example 5 and 0.65% of the lactic acid bacteria fermented rice bran extract prepared in Example 8 were added to the base material. The mixture was stirred at 125 r / min for 15 min. 0.025% of the total mass of the base material and a calcium chloride solution with a concentration of 0.7 mol / L were added and stirred evenly. The pH was adjusted to 6.6 with 1 mol / L hydrochloric acid or sodium hydroxide. (ii) Curdling: Add 0.0025% of the total mass of the base material of compound enzyme curdling agent (abomalacin and microbial curdling enzyme in a mass ratio of 3.5:2.5), stir at 55 r / min for 6 min, heat to 33℃, keep stirring at 55 r / min, and keep warm for 45 min until a uniform curd block is formed. (iii) Cutting: Cut the curd block into 1 cm × 1 cm × 1 cm cubes. Keep the blade flat during the cutting process to avoid the curd block from breaking. Let it stand for 10 minutes to allow the surface of the curd block to initially solidify. (iv) Whey drainage: A gradient temperature increase method is used for processing. First stage: Keep warm at 38℃ for 5 minutes, slowly increase the internal temperature of the curd block; Second stage: Keep warm at 39℃ for 10 min to promote whey separation from the superficial layer of the curd network; Third stage: Keep warm at 40℃ for 15 minutes to accelerate the removal of deep whey from the curd network; Whey separation: 65% of the whey is removed by filtration using an inclined filter screen (0.5 mm pore size), and the curd is collected after whey removal; (v) Pressing: Pressing: The curd blocks after whey removal are evenly filled into the mold (with the inner wall lined with breathable gauze), placed in a hydraulic press, and pressed at 0.25 MPa at 26℃ for 2.5 h; during the pressing process, the pressure is released for 1 min every 30 min to remove residual air in the mold and ensure that the density of the curd blocks is uniform, thus obtaining the pressed curd blocks. (vi) Maturity: Early maturation stage: Transfer the pressed curd blocks to the maturation room and let them stand for 10 days at 9°C and 88% relative humidity. During this period, turn them over every 5 days to prevent local moisture accumulation in the curd blocks. Pulsed electric field maturation: The curd block was transferred to a high-voltage pulsed electric field solid treatment chamber for treatment. The electric field strength was 7 kV / cm. Intermittent treatment was used, with each pulse treatment lasting 30 seconds followed by a 30-second interval. The total cumulative treatment time was 10 minutes. The temperature was 9℃ and the relative humidity was 88%. Late maturation: Mature for 8 days at 9℃ and 88% relative humidity until a uniform maturation layer forms on the surface of the cheese and there is no hard core inside, thus obtaining low-fat cheese containing grain fermentation products.

[0042] Comparative Example 1 The difference between this comparative example and Example 9 is that no modified spirulina polysaccharide was added; the remaining steps and parameters are the same as in Example 9.

[0043] Comparative Example 2 The difference between this comparative example and Example 9 is that the amount of modified spirulina polysaccharide added is 0.05%, while the remaining steps and parameters are the same as in Example 9.

[0044] Comparative Example 3 The difference between this comparative example and Example 9 is that no lactic acid bacteria fermented rice bran extract was added; the remaining steps and parameters are the same as in Example 9.

[0045] Comparative Example 4 The difference between this comparative example and Example 9 is that the amount of lactic acid bacteria fermented rice bran extract added is 1.0%, while the remaining steps and parameters are the same as in Example 9.

[0046] Comparative Example 5 The difference between this comparative example and Example 10 is that the mass ratio of low-fat protein raw material to complex fat substitute is 6.8:3.2, while the remaining steps and parameters are the same as in Example 10.

[0047] Comparative Example 6 The difference between this comparative example and Example 10 is that the mass ratio of low-fat protein raw material to complex fat substitute is 8.2:1.8, while the remaining steps and parameters are the same as in Example 10.

[0048] Comparative Example 7 The difference between this comparative example and Example 12 is that the mass ratio of abomasal enzyme to microbial chymotrypsin in the compound enzyme chymotrypsin is 2:3, while the remaining steps and parameters are the same as in Example 12.

[0049] Comparative Example 8 The difference between this comparative example and Example 12 is that the amount of compound enzyme coagulant added is 0.001%, while the remaining steps and parameters are the same as in Example 12.

[0050] Comparative Example 9 The difference between this comparative example and Example 14 is that the whey was drained at a constant temperature of 40°C for 30 minutes, while the other steps and parameters were the same as in Example 14.

[0051] Comparative Example 10 The difference between this comparative example and Example 14 is that the whey removal rate is 55%, and the remaining steps... The steps and parameters are the same as in Example 14.

[0052] Comparative Example 11 The difference between this comparative example and Example 16 is that there is no high-voltage pulse electric field maturation step, while the remaining steps and parameters are the same as in Example 16.

[0053] Comparative Example 12 The difference between this comparative example and Example 16 is that the high-voltage pulse field intensity is 4 kV / cm, while the remaining steps and parameters are the same as in Example 16.

[0054] Performance testing: 1. Fat content was determined according to GB 5009.6-2025; 2. Moisture content was determined according to GB 5009.3-2025; 3. Hardness was measured using a texture analyzer (test probe PP75A, speed 1 mm / s). 4. Acidity is expressed as lactic acid and determined according to GB 5420-2021 "Cheese" standard; 5. Shelf life is determined under refrigerated conditions at 4℃; The results are shown in Table 1 below: Table 1

[0055] As shown in Table 1 above, the low-fat cheese containing fermented grains prepared in the embodiments of the present invention has a fat content of 1.59%-2.95%, a moisture content of 42.97%-47.71%, a hardness of 369.62g-633.08g, an acidity of 0.42g / 100g-0.48g / 100g, and a shelf life of 31d-39d. In contrast, Comparative Example 1, without the addition of modified spirulina polysaccharide, showed an increased moisture content of 46.75% and a decreased hardness of 388.58g compared to Example 9, with a shortened shelf life of 35d. This indicates that modified spirulina polysaccharide helps maintain the water retention and structural stability of the cheese. Comparative Example 2, with an addition of only 0.05%, showed a fat content of 2.05% similar to Example 9, but a higher hardness of 467.01g compared to Comparative Example 1, and a shelf life of only 30d. This indicates that insufficient addition cannot fully exert its water-retaining, antibacterial, and structural support effects. Compared to Example 9, Comparative Example 3 showed an increased fat content of 2.91%, a hardness of 427.54 g, and a shelf life of only 30 days, indicating that rice bran extract plays an important role in regulating fat distribution and improving flavor stability. Comparative Example 4, with an addition of 1.0%, showed a decrease in moisture content to 43.85% and an abnormal increase in hardness to 515.19 g, demonstrating that excessive addition leads to an overly hard cheese texture and accelerated moisture loss. Compared to Example 10, Comparative Example 5 showed an increased fat content of 2.02% and a hardness of 406.52 g, indicating that an excessively high proportion of fat substitute actually resulted in a rebound in fat content and a softer texture. Comparative Example 6 showed a significant increase in fat content to 4.08% and a shortened shelf life to 32 days, demonstrating that insufficient fat substitutes cannot effectively reduce fat content and also shorten shelf life.

[0056] In Comparative Example 7, the mass ratio of abomasal enzyme to microbial rennet was 2:3. Compared with Example 11, the moisture content was 46.30%, the hardness was 496.74g, and the shelf life was 36 days, indicating that an improper rennet ratio leads to excessively rapid curdling, coarse texture, and abnormally high hardness. Comparative Example 8, with an addition of only 0.001%, shows that insufficient rennet results in incomplete curdling, poor whey separation, and deterioration in texture. Comparative Example 9, after being kept at a constant temperature of 40℃ for 30 minutes, showed a decrease in fat content to 1.27%, an increase in moisture content to 46.91%, a hardness of 459.32g, and an acidity of 0.51g / 100g, indicating that constant-temperature whey removal causes excessively rapid whey removal, fat loss, and increased acidity. Comparative Example 10, with a whey removal rate of only 55%, shows that insufficient whey removal leads to increased moisture, a relatively higher fat content, and decreased hardness, while the shelf life is actually extended (possibly related to the increased fat content). Comparative Example 11, without the pulsed electric field maturation step, showed a decrease in moisture content to 43.75%, an increase in hardness to 580.28 g, and a slight shortening of shelf life to 30 days. This indicates that the pulsed electric field helps maintain appropriate moisture, improve hardness, and extend shelf life. Comparative Example 12, with an electric field strength of only 4 kV / cm, showed a moisture content of 43.80% and a hardness of 572.60 g. This demonstrates that insufficient electric field strength cannot fully utilize the electroporation effect and charge rearrangement, resulting in limited improvement in texture, although the shelf life is still extended to some extent.

[0057] 6. Key aroma components were determined using gas chromatography-mass spectrometry (GC-MS) and expressed as relative peak areas. Characteristic aroma compounds of cheese (ethyl acetate, 3-hydroxy-2-butanone, 2,3-butanediol) were selected. Some results are shown in Table 2 below: Table 2 Key aroma components of some examples and comparative examples

[0058] From the above table 2 and Figure 1-7It can be seen that the low-fat cheese containing fermented grains prepared in the embodiments of the present invention has a rich content and harmonious proportion of key aroma components. The relative peak areas of ethyl acetate, 3-hydroxy-2-butanone, and 2,3-butanediol in Example 10 are 2.995, 6.28, and 4.561, respectively, while those in Example 16 are 3.135, 3.858, and 2.904, respectively. All three characteristic aroma substances are maintained at appropriate levels, giving the cheese a rich and pure milky aroma and fermented flavor. In Comparative Example 4, due to excessive lactic acid bacteria fermented rice bran extract, 2,3-butanediol is abnormally high (7.182), which may produce a sweet off-flavor. In Comparative Example 6, due to insufficient fat substitutes, 3-hydroxy-2-butanone is too high (7.216), resulting in decreased flavor harmony. In Comparative Example 8, due to insufficient rennet, ethyl acetate is high (3.455), but 3-hydroxy-2-butanone is low (1.354), resulting in a monotonous flavor. In Comparative Example 10, due to insufficient whey drainage, 2,3-butanediol levels rose sharply to 19.954. This is related to the increased water activity of the curd and abnormal fermentation metabolism caused by insufficient whey drainage, resulting in an overly sweet and cloying flavor in the product. In Comparative Example 12, due to insufficient pulsed electric field strength, ethyl acetate levels abnormally rose to 5.526, resulting in an overly strong ester aroma that masked other flavor profiles.

[0059] 7. Sensory evaluation (1) The evaluation was conducted by a 10-person professional review panel using a blind review method, and the average score was taken. (2) Total score is 100 points, of which color is 20 points, flavor is 30 points, texture is 30 points and taste is 20 points; (3) The evaluation criteria are refined based on the sensory requirements of GB 5420-2021 "Cheese";

[0060] The results are shown in Table 3 below: Table 3 Sensory Evaluation

[0061] From the above table 3 and Figure 8It can be seen that the total sensory scores of the low-fat cheese containing fermented grains in the embodiments of the present invention are all above 88.3 points, with Example 12 achieving the highest total score of 92.9 points. All dimensions of the scores are in the excellent range, exhibiting uniform and glossy color, rich and pure milky aroma, dense and smooth texture, and delicate and smooth mouthfeel. In contrast, the total sensory scores of the comparative examples are all below 81.0 points, with the lowest being only 70.1 points (Comparative Example 8), indicating significant sensory defects: Comparative Examples 1-2, due to the lack of or insufficient addition of modified spirulina polysaccharides, resulted in loose texture, insufficient gloss, and a soft mouthfeel; Comparative Examples 3-4, due to the lack of or excessive addition of lactic acid bacteria fermented rice bran extract, resulted in a bland or bitter flavor and a rough mouthfeel, with Comparative Example 3 scoring only 11.6 points, indicating poor edibility; Comparative Examples 5-6 had uneven color, loose or overly hard texture; Comparative Examples 7-8 had a rough texture, obvious whey separation, and insufficient flavor; Comparative Examples 9-10 had a soft or dry mouthfeel; and Comparative Examples 11-12 exhibited poor texture and flavor. Therefore, it can be seen that by optimizing process parameters and the synergistic effect of each component, the present invention significantly improves the sensory quality of low-fat cheese containing grain fermentation products, and solves the problems of poor taste, flavor and texture of traditional low-fat cheese containing grain fermentation products.

[0062] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, without departing from the spirit and technical essence of the present invention. Therefore, any simple modifications, equivalent substitutions, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the content of the technical solutions of the present invention, shall still fall within the scope of protection of the present invention.

Claims

1. A method for preparing low-fat cheese containing fermented grains, characterized in that, Includes the following steps: (a) Raw material mixing: Mix the low-fat protein raw material and the complex fat substitute to obtain the base material, add the modified spirulina polysaccharide and grain fermentation product, stir at 100-150 r / min for 15 min, add calcium chloride solution, stir evenly, and adjust the pH to 6.5-6.

7. (ii) Curdling: Add compound enzyme curdling agent, stir at 50-60 r / min for 5-7 min, heat to 32-34℃, keep stirring at 50-60 r / min, keep warm for 40-50 min until a uniform curd block is formed; (iii) Cutting: Cut the curd block into cubes and let stand for 10 minutes; (iv) Whey drainage: A gradient temperature increase method is used for processing. First stage: Keep warm at 38℃ for 5 minutes; Second stage: Keep warm at 39℃ for 10 minutes; Third stage: Keep warm at 40℃ for 15 minutes; Whey separation: 60%-70% of the whey is removed by filtration using an inclined filter screen, and the curd is collected after the whey is removed; (v) Pressing: Pressing: The curd blocks after whey removal are evenly filled into the mold and placed in a hydraulic press. A pressure of 0.2-0.3 MPa is applied at 25-28℃ and the press is pressed for 2-3 hours. During the pressing process, the pressure is released for 1 minute every 30 minutes to remove residual air in the mold and obtain the pressed curd blocks. (vi) Maturity: Early maturation stage: Transfer the pressed curd blocks to the maturation room and let them stand for 10 days at 8-10℃ and 85%-90% relative humidity, turning them over every 5 days during this period; Pulsed electric field maturation: The curd block is transferred to a high-voltage pulsed electric field solid processing chamber for further processing; Late maturation stage: Mature for 5-10 days at 8-10℃ and 85%-90% relative humidity to obtain low-fat cheese containing grain fermentation products.

2. The method for preparing low-fat cheese containing grain fermentation products according to claim 1, characterized in that, The mass ratio of the low-fat protein raw material and the complex fat substitute mentioned in step (I) is 7:3-8:2; the low-fat protein raw material is a mixture of low-fat milk protein and plant protein in a ratio of (8:2)-(9:1); the complex fat substitute is a mixture of octenyl succinic anhydride modified inulin and monoglyceride.

3. The method for preparing low-fat cheese containing fermented grains according to claim 1, characterized in that, The amount of modified spirulina polysaccharide added in step (I) is 0.1%-0.2% of the total mass of the base material; the amount of grain fermentation product added is 0.5%-0.8% of the total mass of the base material; the concentration of calcium chloride solution is 0.5-1.0 mol / L, and the amount added is 0.02%-0.03% of the total mass of the base material.

4. The method for preparing low-fat cheese containing grain fermentation products according to claim 1, characterized in that, The preparation method of the modified spirulina polysaccharide mentioned in step (I) is as follows: S1. Solution preparation: Take spirulina polysaccharide powder, dissolve it in deionized water, and prepare a solution with a mass concentration of 1%-2%; S2. Alkali denaturation treatment: Adjust the pH of the solution to 9.0-10.0, stir at room temperature for 30-60 min to dissociate the polysaccharide molecular chains into a single-chain random coil conformation; S3. Conformation-induced refolding: Under ultrasonic conditions, the pH was slowly adjusted to 6.5-7.0, and ultrasonic treatment was performed simultaneously. The ultrasonic power was 360 W, the ultrasonic frequency was 40 kHz, the treatment time was 20 min, and the temperature was controlled at 25℃. S4. Stabilization treatment: After sonication, continue stirring for 20-40 min to allow the polysaccharide molecular chains to reassemble into an ordered helical conformation; S5. Drying: Modified spirulina polysaccharide is obtained by freeze-drying or spray drying.

5. The method for preparing low-fat cheese containing grain fermentation products according to claim 1, characterized in that, In step (a), the grain fermentation product is a lactic acid bacteria fermented rice bran extract, and the preparation method is as follows: S1. Rice bran pretreatment: Take fresh rice bran, crush it, mix it with deionized water at a mass ratio of 1:5, gelatinize it in a 95℃ water bath for 30 min, cool it to 30℃, and obtain rice bran paste. S2. Fermentation process: Inoculate with activated Lactobacillus plantarum culture and anaerobic ferment in a 30℃ constant temperature fermenter for 44-48 hours; S3. Extract purification: The fermentation broth is centrifuged at 8000-9000 r / min for 15 min to remove residue. The supernatant is filtered through a 0.22 μm microfiltration membrane, and the collected filtrate is the lactic acid bacteria fermented rice bran extract.

6. The method for preparing low-fat cheese containing fermented grains according to claim 5, characterized in that, The concentration of *Lactobacillus plantarum* bacterial solution mentioned in S2 is 10. 8 CFU / mL, inoculation amount is 3-5% of the mass of rice bran paste.

7. The method for preparing low-fat cheese containing grain fermentation products according to claim 1, characterized in that, The compound enzyme coagulant mentioned in step (II) is abomasal enzyme and microbial rennet in a mass ratio of (3-4):(2-3), and the amount added is 0.002%-0.003% of the total mass of the base material.

8. The method for preparing low-fat cheese containing grain fermentation products according to claim 1, characterized in that, The cube in step (iii) has a size of 1 cm × 1 cm × 1 cm.

9. The method for preparing low-fat cheese containing grain fermentation products according to claim 1, characterized in that, The processing conditions described in step (vi) are: electric field strength 5-10 kV / cm, intermittent processing, total cumulative processing time of 10 min, temperature 8-10℃, and relative humidity 85%-90%.

10. Low-fat cheese containing grain fermentation product prepared by the method according to any one of claims 1-9.

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