Structured fermented milk-based food based on whey protein-functional polysaccharide composite particles and preparation method thereof

Abstract

The invention discloses a whey protein-functional polysaccharide composite particle-based structured fermented milk-based food. The whey protein-functional polysaccharide composite particle-based structured fermented milk-based food is prepared by mixing whey protein-functional polysaccharide composite particles and a fermented milk base and then adding a food stabilizer, the whey protein-functional polysaccharide composite particles are prepared from whey protein and functional polysaccharide in a mass ratio of 1: (0.2-0.5); the fermented milk base is prepared by adding a fermentation strain accounting for 0.01-0.10% of the weight of a milk base raw material into the milk base raw material and fermenting; and the food stabilizer accounts for 0-0.3 wt% of the milk-based raw material. Chewable composite particles are constructed through synergism of whey protein and functional polysaccharide, the composite particles are introduced into a fermented milk-based system to form the structured fermented milk-based food, the whey protein-functional polysaccharide composite particles are innovatively introduced into the fermented milk-based food, and the structure of the particles is regulated and controlled, so that the structural fermented milk-based food is obtained. The chewiness, the structural layering sense and the smooth taste of the product are taken into consideration, and external colloid materials such as jelly or gelatin are not needed.

Description

Technical Field

[0001] This invention relates to the field of dairy processing technology, specifically to a structured fermented milk-based food based on whey protein-functional polysaccharide composite particles and its preparation method. Background Technology

[0002] Fermented milk-based foods are a type of food made primarily from milk or dairy products through fermentation by microorganisms such as lactic acid bacteria. They possess excellent nutritional value and flavor characteristics, and are widely popular among consumers. Traditional fermented milk-based foods are characterized by a smooth and delicate texture, often exhibiting a semi-fluid or gel-like state. Their texture mainly relies on the network structure formed by milk proteins under acidic conditions, resulting in a relatively simple overall taste that fails to meet consumers' demands for a multi-layered textural experience.

[0003] In recent years, fermented dairy products with a sense of structure and chewiness have gradually gained attention. To improve the structural layers and eating experience of fermented dairy-based foods, existing technologies typically achieve texture regulation by adding fruit pieces, jellies, exogenous gel particles, or thickeners and stabilizers. However, these methods often suffer from problems such as poor integration of particles with the matrix, insufficient structural stability, or limited nutritional functions. Furthermore, some exogenous colloidal materials are prone to water separation or structural damage in acidic environments during storage.

[0004] Therefore, it is of great significance to develop a structured fermented milk-based food that enhances the textural level, structural stability, and added value of fermented milk-based foods. Summary of the Invention

[0005] The purpose of this invention is to provide a structured fermented milk-based food product based on whey protein-functional polysaccharide complex particles, and to provide its preparation method is a second objective of this invention. The structured fermented milk-based food product of this invention solves the problems of monotonous taste structure, insufficient textural stability, and unbalanced nutritional structure in existing fermented milk-based foods.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: A structured fermented milk-based food based on whey protein-functional polysaccharide composite particles is prepared by mixing whey protein-functional polysaccharide composite particles and fermented milk base, and then adding a food stabilizer. The whey protein-functional polysaccharide composite particles are prepared by mixing whey protein and functional polysaccharides at a mass ratio of 1:0.2-0.5. The fermented milk base is prepared by adding 0.01-0.10% of the weight of fermentation strain to the milk base raw material and fermenting it. The amount of food stabilizer is 0-0.3 wt% of the milk base raw material.

[0007] Preferably, the amount of the whey protein-functional polysaccharide complex particles is 5–15 wt% of the fermented milk base.

[0008] Preferably, the whey protein is selected from whey protein concentrate (WPC), whey protein isolate (WPI), or a combination thereof.

[0009] Preferably, the functional polysaccharide is selected from konjac glucomannan, oat β-glucan, or a combination thereof.

[0010] Preferably, the fermentation strain is a compound strain of Streptococcus thermophilus and Lactobacillus bulgaricus, or a mixture of the compound strain with any one or two of Lactobacillus casei and Lactobacillus acidophilus.

[0011] Preferably, the food stabilizer is selected from one or a mixture of two or more of pectin, carrageenan, guar gum or sodium carboxymethyl cellulose.

[0012] Preferably, the fermented milk-based food is fermented yogurt.

[0013] The present invention further discloses a method for preparing the structured fermented milk-based food, comprising the following steps: (1) Disperse whey protein and functional polysaccharide in water in proportion, stir thoroughly, and heat treat at 85–95℃ for 8–12 min to cause whey protein to undergo thermal denaturation and synergistic effect with functional polysaccharide to form a stable composite gel structure. After cooling, obtain composite gel, cut or shape into whey protein-functional polysaccharide composite particles with a particle size of 2–4 mm. (2) Heat the milk base raw material at 85–95℃ for 12–15 min to sterilize it, cool it to the fermentation temperature, inoculate it with fermentation bacteria, and ferment it to the target acidity under constant temperature conditions to obtain the fermented milk base system. (3) The whey protein-functional polysaccharide composite particles obtained in step (1) are added to the fermented milk base system and stirred slowly to disperse the composite particles evenly, thus obtaining the structured fermented milk base food.

[0014] Preferably, in step (2), the fermentation temperature is 40–43°C and the time is 5–6 hours.

[0015] This invention innovatively introduces whey protein-functional polysaccharide composite particles into fermented milk-based foods by synergistically constructing chewable composite particles and incorporating them into the fermented milk system. Through particle structure control, it achieves a balance of chewability, layered structure, and smooth texture without relying on exogenous colloidal materials such as jelly or gelatin. The key technical point lies in the synergistic construction of a composite gel by whey protein and functional polysaccharides, and the preparation of these composite particles with controllable particle size (2–4 mm), achieving long-term structural stability, uniform dispersion, and resistance to disintegration in acidic fermented milk systems.

[0016] Compared with the prior art, the present invention has the following beneficial effects: (1) The composite particles formed by whey protein and functional polysaccharides used in this invention have a stable structure in a low pH fermented milk base environment and are not easily disintegrated or separated into water. (2) The composite particles give fermented milk-based foods a distinct sense of structure and chewability, significantly enhancing the sensory quality of the products; (3) The complementary nutritional and functional properties of the whey protein and functional polysaccharides used improve the overall nutritional value of the product; (4) This invention does not rely on exogenous colloids such as gelatin and jelly powder, and the product formula is cleaner and healthier. Detailed Implementation

[0017] To better illustrate the technical solution of the present invention, the following embodiments are provided, but the present invention is not limited thereto.

[0018] It should be noted that the low temperature mentioned in this invention refers to a temperature below room temperature, specifically below 25°C. The milk base raw material used is fresh milk sourced from compliant suppliers. Before entering the factory, it undergoes sensory, physicochemical, and necessary microbiological tests to ensure compliance with national food safety standards and fermented milk production requirements.

[0019] Example 1 This embodiment describes a structured fermented milk-based food product based on whey protein-functional polysaccharide composite particles, the preparation method of which includes the following steps: (1) Weigh 3 g of WPC 80 whey protein powder and 0.8 g of konjac glucomannan and add them to 50 mL of deionized water. After dispersing them thoroughly under magnetic stirring, heat to 90 °C and keep warm for 10 min to allow the whey protein to undergo thermal denaturation and form a complex gel with the functional polysaccharide. After cooling to about 25 °C, cut them into complex particles with a diameter of about 3 mm for later use.

[0020] (2) Take 100 g of fresh milk as the base material and sterilize it at 85 ℃ for 15 min. After cooling to 42 ℃, inoculate it with a compound strain of Streptococcus thermophilus and Lactobacillus bulgaricus (the ratio of the two strains is 1:1). Ferment at 40–43 ℃ for 5–6 h until the acidity reaches 70–80 °T.

[0021] (3) Add the above composite particles to the fermented milk base system at a ratio of 10% (w / w), stir slowly to disperse the particles evenly, add 0.2 g of pectin as a stabilizer, degas and package, and store at 4 ℃.

[0022] The product obtained in this embodiment has a uniform particle distribution, stable structure, and a chewy texture, combining the smooth taste of fermented dairy-based foods with the elastic structure of particles.

[0023] In other embodiments, the fermentation strain may also be a mixture of a complex strain and any one or two of Lactobacillus casei and Lactobacillus acidophilus.

[0024] Example 2 This embodiment is the same as Embodiment 1, except that the functional polysaccharide is replaced with oat β-glucan and the mass ratio of whey protein to functional polysaccharide is adjusted to 1:0.3.

[0025] The composite particle structure obtained in this embodiment is relatively loose, and the suspension stability is slightly reduced, indicating that the synergistic effect between whey protein and different functional polysaccharides has a significant impact on the particle structure performance.

[0026] Example 3 This embodiment is the same as Embodiment 1, except that the particle size of the composite particles is controlled within the range of 3–4 mm.

[0027] The structured fermented milk-based food obtained in this embodiment has a more pronounced chewiness and enhanced satiety, making it suitable for meal replacement or functional dairy products.

[0028] Example 4 This embodiment is the same as Example 1, except that the mass ratio of whey protein to functional polysaccharide is adjusted to 1:0.5.

[0029] The granules obtained in this embodiment have a dense structure, significantly enhanced acid resistance and elasticity, but a firmer texture, making them suitable for consumers who prefer a stronger sense of structure.

[0030] Example 5 This embodiment is the same as Embodiment 1, except that the amount of composite particles added is adjusted to 15% (w / w).

[0031] The product obtained in this embodiment has a significantly enhanced particle texture, but the smoothness of the fermented milk base system is reduced, indicating that the amount of particles added has a significant impact on the overall texture balance of the product.

[0032] Comparative Example 1 This comparative example is the same as Example 1, except that whey protein was not added; only functional polysaccharides were used to prepare the gel particles. The results showed that the obtained particles were prone to disintegration and water separation in the fermented milk-based system, exhibiting significantly insufficient structural stability.

[0033] Comparative Example 2 This comparative example is the same as Example 1, except that no composite particles are added; only ordinary fermented milk-based food is prepared. The resulting product has a fine texture but a monotonous taste and lacks structural depth.

[0034] Effect Example 1. Evaluation of the textural properties of composite particles Parameter settings: Pre-test speed 2 mm / s, test speed 1 mm / s, post-test speed 2 mm / s, test deformation 50%; probe is P / 36 R, measuring the hardness, elasticity, adhesiveness and cohesion of the sample. The test results are shown in Table 1.

[0035] Table 1. Test results of the textural properties of the samples prepared in Examples 1-5 and Comparative Example 1. As shown in Table 1, the samples from different examples exhibited significant differences in textural properties such as hardness, elasticity, adhesiveness, and resilience (P < 0.05). Examples 3 and 5 showed significantly higher hardness and elasticity than other samples, indicating that the composite particle structure formed under suitable whey protein and functional polysaccharide ratios was more compact, thus enhancing the mechanical strength and elastic recovery of the particles. Examples 1, 2, and 4 had moderate textural parameters, indicating relatively stable particle structures, but with lower composite network formation or less compact particle structures. Comparative Example 1 showed significantly lower values ​​than the example groups, especially in hardness and elasticity, indicating insufficient stability of the gel particle structure prepared using only functional polysaccharides. Comparative Example 2 did not form a stable particle structure, further verifying the key role of whey protein-functional polysaccharide composite particles in improving textural properties and chewability.

[0036] Experiment on the characteristics and effects of finished yogurt products To further illustrate the effects of the present invention, the pH, titratable acidity, viscosity and whey separation rate of the samples from Examples 1-5 and Comparative Examples 1-2 were tested, and the results are shown in Table 2.

[0037] Table 2. Test results of the characteristics of the samples prepared in Examples 1-5 and Comparative Examples 1-2. The data in the table show significant differences among the different samples in terms of pH, titratable acidity, viscosity, and whey separation rate. Examples 1–5 exhibited slightly lower pH, moderate acidity, high viscosity, and low whey separation rate, indicating that the formation of whey protein-functional polysaccharide complex particles effectively enhanced the structural stability and viscosity of the fermented milk, while reducing whey separation and improving product texture and mouthfeel. Examples 3 and 5, in particular, showed the highest viscosity and lowest whey separation, demonstrating the significant effect of the complex particles in improving mechanical strength and network structure density. In contrast, Comparative Examples 1 and 2 showed low viscosity and high whey separation rate, indicating that the fermented milk lacking the complex particle structure had significant deficiencies in texture and stability.

[0038] Sensory evaluation Sensory evaluation was conducted on the five samples of Examples 1-5 and the samples of Comparative Examples 1-2, evaluating them across five indicators. Twenty trained sensory evaluators scored the samples based on color, texture, flavor, and mouthfeel. Each indicator had a maximum score of 10 points, with a minimum score of 1 point. The evaluation criteria and corresponding scores for each indicator are shown in Table 3. The sensory evaluation results are shown in Table 4.

[0039] Table 3 Sensory evaluation criteria for yogurt Table 4 Sensory evaluation data As shown in Table 4, the sensory evaluation results revealed differences in color, texture, flavor, and mouthfeel among the samples. Examples 1–5 exhibited high levels of texture and mouthfeel, with no statistically significant differences, indicating that the introduction of whey protein-functional polysaccharide complex particles improved the overall structural stability and palatability of the fermented milk. Examples 2 and 3 showed significantly higher color scores than other samples, indicating that the formation of the complex particles improved the uniformity of the product's appearance and sensory acceptance. Example 5 scored slightly lower in flavor and mouthfeel, possibly due to a higher proportion of complex particles or a harder particle structure. Comparative Examples 1 and 2 showed significantly lower overall sensory indicators than the Example groups, further demonstrating that fermented milk lacking the whey protein-functional polysaccharide complex particle structure has significant deficiencies in sensory quality.

[0040] Based on the results of texture, finished product characteristics, and sensory evaluation, whey protein-functional polysaccharide composite particles significantly improve the structure and quality of fermented milk. Texture testing showed that Examples 3 and 5 exhibited the highest hardness, elasticity, and resilience, with dense particles and an intact composite network, enhancing mechanical strength and elastic recovery. Examples 1, 2, and 4 were at a moderate level, with slightly lower particle structure stability. The comparative group showed significantly insufficient hardness and elasticity, with some samples failing to form stable particles, indicating lower gel network stability due to the use of functional polysaccharides alone to prepare gel particles. The characteristics of the finished yogurt indicated that the Example group had a moderate pH, suitable acidity, high viscosity, and low whey separation rate, with Examples 3 and 5 performing best, as the composite particles enhanced network density and consistency. Sensory evaluation showed that Examples 1–4 had higher texture and mouthfeel scores, while Examples 2 and 3 had the highest color scores. Example 5 had a slightly lower flavor, possibly due to the harder particles. The comparative group had lower sensory indicators than the Example group, further illustrating the deficiencies in texture, stability, and sensory qualities of yogurt lacking composite particles. Overall, whey protein-functional polysaccharide complex particles significantly improve the structure and sensory quality of fermented milk, and have good application potential.

[0041] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A structured fermented milk-based food product based on whey protein-functional polysaccharide complex particles, characterized in that, It is prepared by mixing whey protein-functional polysaccharide complex particles and fermented milk base, and then adding a food stabilizer; the whey protein-functional polysaccharide complex particles are prepared by mixing whey protein and functional polysaccharides at a mass ratio of 1:0.2-0.5; the fermented milk base is prepared by adding 0.01-0.10% of the weight of fermentation bacteria to the milk base raw material; the amount of food stabilizer is 0-0.3 wt% of the milk base raw material.

2. The structured fermented milk-based food based on whey protein-functional polysaccharide composite particles according to claim 1, characterized in that, The amount of the whey protein-functional polysaccharide complex particles is 5–15 wt% of the fermented milk base.

3. The structured fermented milk-based food based on whey protein-functional polysaccharide composite particles according to claim 1, characterized in that, The whey protein is selected from whey protein concentrate (WPC), whey protein isolate (WPI), or a combination thereof.

4. The structured fermented milk-based food based on whey protein-functional polysaccharide composite particles according to claim 1, characterized in that, The functional polysaccharide is selected from konjac glucomannan, oat β-glucan, or a combination thereof.

5. The structured fermented milk-based food based on whey protein-functional polysaccharide composite particles according to claim 1, characterized in that, The fermentation strain is a compound strain of Streptococcus thermophilus and Lactobacillus bulgaricus, or a mixture of a compound strain with any one or two of Lactobacillus casei and Lactobacillus acidophilus.

6. The structured fermented milk-based food product based on whey protein-functional polysaccharide composite particles according to claim 1, characterized in that, The food stabilizer is selected from one or a mixture of two or more of pectin, carrageenan, guar gum, or sodium carboxymethyl cellulose.

7. The structured fermented milk-based food product based on whey protein-functional polysaccharide composite particles according to claim 1, characterized in that, The fermented milk-based food is fermented yogurt.

8. The method for preparing the structured fermented milk-based food according to any one of claims 1-7, characterized in that, Includes the following steps: (1) Disperse whey protein and functional polysaccharide in water in proportion, stir thoroughly, and heat treat at 85–95℃ for 8–12 min to cause whey protein to undergo thermal denaturation and synergistic effect with functional polysaccharide to form a stable composite gel structure. After cooling, obtain composite gel, cut or shape into whey protein-functional polysaccharide composite particles with a particle size of 2–4 mm. (2) Heat the milk base raw material at 85–95℃ for 12–15 min to sterilize it, cool it to the fermentation temperature, inoculate it with fermentation bacteria, and ferment it to the target acidity under constant temperature conditions to obtain the fermented milk base system. (3) Add the whey protein-functional polysaccharide complex particles obtained in step (1) to the fermented milk base obtained in step (2), mix evenly, and obtain fermented milk base food.

9. The method for preparing structured fermented milk-based food according to claim 1, characterized in that, In step (2), the fermentation temperature is 40–43°C and the time is 5–6 hours.

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