Classification method for whey protein powder texture function, classification model, and use thereof in yoghurt

Abstract

The present invention relates to a classification method for whey protein powder texture function, a classification model, and the use thereof in yoghurt. The classification method comprises: testing the solubility a, the hydrated particle size b, the gel strength c, and the acid / heat-treated particle size d of whey protein powder, and classifying same according to the numerical ranges of these parameters. The classification method provided in the present invention can achieve rapid identification and application recommendation of whey protein powder texture function, and not only eliminates quality risks caused by the difference in raw materials at the starting material end, but also improves the development efficiency of a product.

Description

A classification method and model for the textural functions of whey protein powder and its application in yogurt.

[0001] This application claims priority to Chinese invention patent application filed on January 23, 2025, with application number 202510104616.1 and entitled "A classification method, classification model and application of whey protein powder texture function in yogurt". Technical Field

[0002] This invention relates to the field of analytical testing technology, and in particular to a classification method and model for the textural function of whey protein powder and its application in yogurt. Background Technology

[0003] Whey protein is a protein extracted from milk. It is characterized by high nutritional value, easy digestibility and absorption, and the presence of various active ingredients, making it a recognized high-quality protein supplement for the human body. It accounts for approximately 18% to 20% of milk protein and can be divided into heat-stable and heat-labile whey proteins. Heat-labile whey proteins, mainly including lactalbumin and lactoglobulin, precipitate when whey is boiled for 20 minutes at pH 4.6–4.7. Due to its high absorption rate and optimal amino acid composition, whey protein is hailed as the "king of proteins." It is not only easily digestible but also possesses high biological value, high digestibility, high protein-to-energy ratio, and high utilization rate, making it a recognized high-quality protein supplement for the human body. Currently, it is widely used in sports nutrition, weight management, and geriatric nutrition, among other fields. Technological innovation has played a crucial role in improving whey protein purity and enhancing the taste and texture of food. Technologies such as ultrafiltration, microfiltration, ion exchange, and physical modification have diversified the functions of whey protein raw materials, meeting the application needs of different products.

[0004] Current methods for evaluating the textural contribution of whey protein powder raw materials are still limited to small-scale testing in food systems. This approach often fails to accurately identify differences between raw materials due to the small amount of whey protein added in the food formulation. Sometimes, raw materials with opposite characteristics are even selected as reserves. Once the amount added to the formulation increases, this difference will be amplified, leading to product quality risks.

[0005] Therefore, it is necessary to provide a classification method for the textural functions of whey protein powder, to eliminate the quality risks caused by raw material differences from the raw material end, reduce the workload of product development, and improve work efficiency. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a classification method and model for the textural functions of whey protein powder, and its application in yogurt. The classification method provided by this invention is based on four characteristic indicators of whey protein powder: solubility, hydrated particle size, gel strength, and acid-heat treated particle size. This allows for rapid identification of the textural functions of whey protein powder and provides reasonable application recommendations. This classification method not only eliminates quality risks caused by raw material differences from the raw material perspective but also reduces the workload of product developers and improves product development efficiency.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a method for classifying the textural functions of whey protein powder, the classification method comprising:

[0009] The solubility (a), hydrated particle size (b), gel strength (c), and acid-heat treated particle size (d) of whey protein powder were tested and classified according to the following standards:

[0010] When 96≤a≤100 (e.g., it can be 96, 97, 98, 99, 100, etc.), 0≤b≤22 (e.g., it can be 0, 4, 8, 12, 16, 20, 22, etc.), 170≤c≤1200 (e.g., it can be 170, 180, 200, 500, 1000, 1200, etc.), and 28≤d≤140 (e.g., it can be 28, 30, 50, 80, 100, 120, 140, etc.), whey protein powder belongs to the texture-enhanced type.

[0011] When 99≤a≤100 (e.g., it can be 99, 99.2, 99.4, 99.6, 99.8, 100, etc.), 0≤b≤0.1 (e.g., it can be 0, 0.01, 0.02, 0.04, 0.06, 0.08, 0.1, etc.), c=0, and 110≤d≤140 (e.g., it can be 110, 115, 120, 125, 130, 135, 140, etc.), whey protein powder belongs to the isolated type.

[0012] When 15≤a≤55 (e.g., it can be 15, 20, 25, 30, 35, 40, 45, 50, 55, etc.), 35≤b≤130 (e.g., it can be 35, 50, 80, 100, 120, 130, etc.), c=0, and 1≤d≤22 (e.g., it can be 1, 5, 10, 15, 20, 22, etc.), whey protein powder belongs to the micronized type.

[0013] When the values ​​of a, b, c, and d do not meet any of the above conditions, the whey protein powder is heat-stable.

[0014] Existing methods for evaluating the textural contribution of whey protein powder often suffer from limitations due to the low concentration of whey protein in food formulations, making it difficult to accurately identify differences between raw materials. This can easily lead to product quality risks and negatively impact product development efficiency. To address this, this invention creatively provides a classification method for the textural function of whey protein powder based on four key characteristics: solubility, hydrated particle size, gel strength, and acid-heat treated particle size. This classification method enables rapid identification of the textural function of whey protein powder and provides reasonable application recommendations. It not only eliminates quality risks caused by raw material differences but also reduces the workload of product developers and improves product development efficiency.

[0015] Preferably, the solubility testing method includes: mixing whey protein powder and water, centrifuging to remove the supernatant, drying the precipitate to constant weight, and calculating the solubility based on the initial water content of the whey protein powder; the solubility calculation formula is as follows:

[0016] Where X represents the solubility of whey protein powder, in g / 100g; m1 represents the mass of the dried precipitate, in g; B represents the initial moisture content of the whey protein powder, in g / 100g; and m0 represents the mass of the whey protein powder, in g.

[0017] Preferably, the mixing temperature is 45-55℃ (e.g., 45℃, 46℃, 48℃, 50℃, 52℃, 54℃, 55℃, etc.).

[0018] Preferably, the method for testing the hydrated particle size includes: mixing whey protein powder and water, allowing it to stand for hydration, and then performing a particle size test.

[0019] Preferably, the mixing temperature is 45-55℃ (e.g., 45℃, 46℃, 48℃, 50℃, 52℃, 54℃, 55℃, etc.), and the mixing time is 20-40min (e.g., 20min, 25min, 30min, 35min, 40min, etc.).

[0020] Preferably, the hydration temperature is 20-30℃ (e.g., 20℃, 22℃, 24℃, 26℃, 28℃, 30℃, etc.), and the hydration time is 0.5-1.5h (e.g., 0.5h, 0.6h, 0.8h, 1h, 1.2h, 1.4h, 1.5h, etc.).

[0021] Preferably, the method for testing gel strength includes: mixing whey protein powder and water, allowing it to stand for hydration, then homogenizing, heating and cooling, and then conducting a gel strength test.

[0022] Preferably, the mixing temperature is 45-55℃ (e.g., 45℃, 46℃, 48℃, 50℃, 52℃, 54℃, 55℃, etc.), and the mixing time is 20-40min (e.g., 20min, 25min, 30min, 35min, 40min, etc.).

[0023] Preferably, the hydration temperature is 20-30℃ (e.g., 20℃, 22℃, 24℃, 26℃, 28℃, 30℃, etc.), and the hydration time is 20-40min (e.g., 20min, 25min, 30min, 35min, 40min, etc.).

[0024] Preferably, the primary pressure for homogenization is 100-200 bar (e.g., 100 bar, 120 bar, 150 bar, 180 bar, 200 bar, etc.), and the secondary pressure for homogenization is 20-40 bar (e.g., 20 bar, 25 bar, 30 bar, 35 bar, 40 bar, etc.).

[0025] Preferably, the heating temperature is 80-90℃ (e.g., 80℃, 82℃, 84℃, 86℃, 88℃, 90℃, etc.), and the heating time is 40-50min (e.g., 40min, 42min, 44min, 46min, 48min, 50min, etc.).

[0026] Preferably, the cooling temperature is 20-30°C (e.g., 20°C, 22°C, 24°C, 26°C, 28°C, 30°C, etc.).

[0027] Preferably, the method for testing the particle size after acid heat treatment includes: mixing whey protein powder and water, allowing it to stand for hydration, then homogenizing, and cooling after a first heating; adding an acidic reagent to adjust the pH, and cooling after a second heating, and then testing the particle size.

[0028] Preferably, the mixing temperature is 40-50℃ (e.g., 40℃, 42℃, 45℃, 48℃, 50℃, etc.), and the mixing time is 20-40min (e.g., 20min, 25min, 30min, 35min, 40min, etc.).

[0029] Preferably, the hydration temperature is 20-30℃ (e.g., 20℃, 22℃, 24℃, 26℃, 28℃, 30℃, etc.), and the hydration time is 20-40min (e.g., 20min, 25min, 30min, 35min, 40min, etc.).

[0030] Preferably, the primary pressure for homogenization is 100-200 bar (e.g., 100 bar, 120 bar, 150 bar, 180 bar, 200 bar, etc.), and the secondary pressure for homogenization is 20-40 bar (e.g., 20 bar, 25 bar, 30 bar, 35 bar, 40 bar, etc.).

[0031] Preferably, the temperature of the first heating is 80-90℃ (e.g., 80℃, 82℃, 84℃, 86℃, 88℃, 90℃, etc.), and the heating time is 5-10min (e.g., 5min, 6min, 7min, 8min, 9min, 10min, etc.).

[0032] Preferably, the first heating is followed by cooling to a temperature of 38-45°C (e.g., 38°C, 40°C, 42°C, 44°C, 45°C, etc.).

[0033] Preferably, the acidic reagent includes any one or a combination of at least two of lactic acid, citric acid, or hydrochloric acid.

[0034] Preferably, the pH is adjusted to 4.3-4.5 (e.g., 4.3, 4.4, 4.5, etc.).

[0035] Preferably, the temperature of the second heating is 70-80℃ (e.g., 70℃, 72℃, 74℃, 76℃, 78℃, 80℃, etc.), and the heating time is 0.5-5min (e.g., 0.5min, 1min, 2min, 3min, 4min, 5min, etc.).

[0036] Preferably, the second heating is followed by cooling to a temperature of 20-30°C (e.g., 20°C, 22°C, 24°C, 26°C, 28°C, 30°C, etc.).

[0037] Secondly, the present invention provides a classification model for the textural function of whey protein powder, the classification model including a detection unit and an analysis unit;

[0038] The detection unit includes tests for the solubility (a), hydrated particle size (b), gel strength (c), and acid-heat treated particle size (d) of whey protein powder.

[0039] The analytical unit includes a classification system that performs textural functions on whey protein powder, and the classification criteria include:

[0040] When 96≤a≤100, 0≤b≤22, 170≤c≤1200, and 28≤d≤140, whey protein powder belongs to the texture-enhanced type.

[0041] When 99≤a≤100, 0≤b≤0.1, c=0, and 110≤d≤140, whey protein powder belongs to the isolated type;

[0042] When 15≤a≤55, 35≤b≤130, and c=0, and 1≤d≤22, whey protein powder belongs to the micronized type.

[0043] When the values ​​of a, b, c, and d do not meet any of the above conditions, the whey protein powder is heat-stable.

[0044] Thirdly, the present invention provides a method for constructing a classification model of the textural function of whey protein powder according to the second aspect, characterized in that the construction method includes the following steps:

[0045] (1) Detect the raw material characteristics of whey protein powder;

[0046] (2) Perform cluster analysis on the data information obtained in step (1) and obtain a classification model of whey protein powder texture function based on the analysis results;

[0047] (3) Take whey protein powder to verify the classification model obtained in step (2).

[0048] Preferably, the raw material characteristics in step (1) include a combination of solubility, hydrated particle size, gel strength and acid-heat treated particle size.

[0049] Fourthly, the present invention provides a classification model system for the textural function of whey protein powder, the classification model system comprising a detection unit device and an analysis unit device;

[0050] The detection unit includes a testing device for solubility (a), hydrated particle size (b), gel strength (c), and acid-heat treated particle size (d) of whey protein powder.

[0051] The analytical unit includes a device for classifying whey protein powder according to its textural function, the classification criteria including:

[0052] When 96≤a≤100, 0≤b≤22, 170≤c≤1200, and 28≤d≤140, whey protein powder belongs to the texture-enhanced type.

[0053] When 99≤a≤100, 0≤b≤0.1, c=0, and 110≤d≤140, whey protein powder belongs to the isolated type;

[0054] When 15≤a≤55, 35≤b≤130, and c=0, and 1≤d≤22, whey protein powder belongs to the micronized type.

[0055] When the values ​​of a, b, c, and d do not meet any of the above conditions, the whey protein powder is heat-stable.

[0056] A classification model system for the textural function of whey protein powder is also provided, including a detection unit and an analysis unit;

[0057] The detection unit is configured to perform tests on the solubility (a), hydrated particle size (b), gel strength (c), and acid-heat treated particle size (d) of whey protein powder.

[0058] The analysis unit is configured to perform textural classification of whey protein powder, and the classification criteria include:

[0059] When 96≤a≤100, 0≤b≤22, 170≤c≤1200, and 28≤d≤140, whey protein powder belongs to the texture-enhanced type.

[0060] When 99≤a≤100, 0≤b≤0.1, c=0, and 110≤d≤140, whey protein powder belongs to the isolated type;

[0061] When 15≤a≤55, 35≤b≤130, and c=0, and 1≤d≤22, whey protein powder belongs to the micronized type.

[0062] When the values ​​of a, b, c, and d do not meet any of the above conditions, the whey protein powder is heat-stable.

[0063] In some embodiments, the detection device includes a memory device storing instructions configured to perform any one, two, three, or four of the following: solubility (a), hydrated particle size (b), gel strength (c), and acid-heat treated particle size (d) of the whey protein powder. The detection device may also include a laser particle size analyzer that can accept instructions from the memory device to detect particle size (e.g., hydrated particle size and / or acid-heat treated particle size). The detection device may also include a texture analyzer that can accept instructions from the memory device to detect particle gel strength. The detection device may also include a weighing device that can accept instructions from the memory device to detect the weight of the test sample, thereby calculating the solubility of the whey protein powder. In some embodiments, the analytical unit device includes a memory device storing instructions that perform classification of the texture function of the whey protein powder.

[0064] A classification model system for the textural function of whey protein powder is also provided, characterized in that the classification model system includes a processor; and a memory storing a program containing instructions that, when executed by the processor, cause the processor to perform the method described herein.

[0065] Fourthly, the present invention provides an application of the classification method for the textural functions of whey protein powder according to the first aspect, the classification model for the textural functions of whey protein powder according to the second aspect, or the classification model system described herein, in the development of dairy products.

[0066] Compared with the prior art, the present invention has at least the following beneficial effects:

[0067] The present invention provides a textural function classification method based on four characteristic indicators of whey protein powder: solubility, hydrated particle size, gel strength, and acid-heat treated particle size. This method can quickly identify the textural function of whey protein powder and provide reasonable application recommendations. This classification method can not only eliminate quality risks caused by raw material differences from the raw material end, but also reduce the workload of product developers and improve product development efficiency. Attached Figure Description

[0068] Figure 1 is a cluster analysis diagram of whey protein raw materials in step (3) of Example 1.

[0069] Figure 2 is a cluster analysis diagram of whey protein raw material verification in step (4) of Example 1.

[0070] Figure 3 is a principal component analysis diagram of the yogurt model system in step (5) of Example 1. Detailed Implementation

[0071] The terminology used in the description of the various examples described in this disclosure is for the purpose of describing particular examples only and is not intended to be limiting. Unless the context explicitly indicates otherwise, an element may be one or more unless the number of elements is specifically limited. Furthermore, the term "and / or" as used in this disclosure covers any one of the listed items and all possible combinations thereof.

[0072] In this article, "whey protein powder" refers to a powdered dairy product with a high protein content, made from whey through processes such as separation, concentration, and drying. It is an enriched product of whey protein components from cow's milk and is an important food ingredient and nutritional fortifier. Its main nutrients include β-lactoglobulin, α-lactalbumin, immunoglobulins, and lactoferrin.

[0073] In this article, "texture functionality" refers to the sum of physical structural properties of whey protein powder that can be perceived by the senses or instruments. Based on solubility, hydrated particle size, gel strength, and acid-heat treated particle size, whey protein powder can be classified into texture-enhancing, separation, micronized, and heat-stable types.

[0074] In this paper, the "solubility" of whey protein powder refers to the percentage of protein mass in the supernatant / filtrate of the sample after centrifugation or filtration, when whey protein powder is dispersed in water under specified conditions. It reflects the dissolving and dispersing ability of whey protein in an aqueous system and is an important indicator affecting its textural function, processing suitability, and product stability. The solubility test method described in this paper includes: mixing whey protein powder and water, centrifuging to remove the supernatant, drying the precipitate to constant weight, and calculating the solubility based on the initial water content of the whey protein powder.

[0075] When used in this article, the “hydrated particle size” of whey protein powder refers to the particle size of the particles formed after hydration. The method for testing the hydrated particle size in this article includes mixing whey protein powder and water, allowing it to stand for hydration, and then measuring the particle size. For example, a whey protein powder solution with a protein content of 1%-5% can be used, and the hydrated particle size can be determined after hydration. This can be determined using a laser particle size analyzer.

[0076] When used herein, the “gel strength” of whey protein powder refers to the strength of the gel formed when whey protein powder forms a gel in water. The gel strength testing method described herein includes: mixing whey protein powder and water, allowing it to hydrate, then homogenizing, heating, and cooling before performing a gel strength test. For example, a whey protein powder solution with an 8%-15% protein content can be used, and the gel strength can be determined by hydration and homogenization, followed by heating and cooling. This can be determined under weak gel testing conditions. Specifically, a texture analyzer can be used for puncture testing; pre-test speed 1.0 mm / s, test speed 0.5 mm / s, post-test retraction speed 10 mm / s, insertion distance 20 mm, and trigger force 2 g. A weak gel test refers to the rheological characterization of a weak gel system formed by heating, cooling, or ion-induced gelation of a whey protein dispersion under a small-amplitude oscillatory shear mode. In some embodiments, a texture analyzer is used to detect gel strength.

[0077] When used herein, the "acid-heat treated particle size" of whey protein powder refers to the hydrated particle size of whey protein powder measured in a dispersion system after acid adjustment and heat treatment. The method for testing the acid-heat treated particle size in this document includes: mixing whey protein powder and water, allowing it to hydrate statically, then homogenizing, followed by a first heating and cooling; adding an acidic reagent to adjust the pH, followed by a second heating and cooling, and then testing the particle size. For example, a whey protein powder solution with a protein content of 1%-5% can be used, allowed to hydrate statically, then homogenized, followed by a first heating and cooling; adding an acidic reagent to adjust the pH (e.g., to 4.3-4.5), followed by a second heating and cooling, and then testing the particle size.

[0078] When used in this article, "texture-enhancing" refers to whey protein powder with the following parameters: 96≤a≤100, 0≤b≤22, 170≤c≤1200, 28≤d≤140. This type of whey protein exhibits the highest gel strength, indicating that it forms a gel network structure, which enhances the texture of the product.

[0079] When used in this article, "isolated type" refers to whey protein powder with the following parameter characteristics: 99≤a≤100, 0≤b≤0.1, c=0, 110≤d≤140. This type of whey protein is extremely soluble in water and has a particularly small particle size after hydration. The large particle size under acid and heat indicates poor acid and heat stability, but it does not form a gel, which is consistent with the characteristics of isolated whey protein.

[0080] When used in this article, "micronized" refers to whey protein powder with the following parameter characteristics: 15≤a≤55, 35≤b≤130, and when c=0, 1≤d≤22. This type of whey protein has the worst solubility and the highest hydrated particle size. Its very small acid-heat particle size indicates high acid-heat stability, and it cannot form a gel, which is consistent with the characteristics of micronized whey protein.

[0081] When used in this article, "heat-stable" refers to whey protein powder that exhibits parameter characteristics different from those of "texture-enhanced," "separate," and "micronized" whey proteins. The heat stability of this type of whey protein is second only to micronized whey protein.

[0082] This invention shows that adding texture-enhancing whey proteins to yogurt products results in a sticky and thick texture, even a powdery feel, which is directly related to their texture-enhancing properties. Similarly, adding isolated whey proteins to yogurt also contributes to a sticky, thick, and powdery texture, even exhibiting a granular surface. This is directly related to the higher content of active proteins in isolated whey proteins, meaning more active whey proteins participate in the formation of the yogurt structure, making the yogurt gel network less susceptible to agitation and shearing damage, thus resulting in visible gel particles. Micronized and heat-stable whey proteins both exhibit smooth and refreshing characteristics in yogurt applications. This is directly related to their strong acid-heat stability and their tendency to not form gels or form weak gels. It is speculated that these proteins do not participate in or minimally participate in the formation of the yogurt gel network, but rather are inertly embedded in the pores of the yogurt network, thus not increasing the strength of the product's texture, but instead giving the product a smooth and refreshing feel. Compared to heat-stable whey proteins, micronized whey proteins provide a stronger smoothness to the product, but have lower stability.

[0083] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

[0084] Example 1

[0085] This embodiment provides a method for constructing a classification model of the textural function of whey protein powder, specifically including the following steps:

[0086] (1) Collection and information organization of whey protein raw materials

[0087] We collected 18 whey protein raw materials from multiple suppliers, with different manufacturers, models, and functional claims, and compiled the information as shown in Table 1.

[0088] Table 1

[0089] (2) Raw material property testing

[0090] For each sample, three parallel samples were set up for the following raw material characteristic tests.

[0091] ① Solubility:

[0092] a. Weigh 5g of the sample (accurate to 0.01g) into a 50mL centrifuge tube, add 38mL of water and milk powder to the centrifuge tube, stir and disperse with a glass rod, stopper the tube, shake at 20rpm for 2.5h, and refrigerate at 4℃ overnight.

[0093] b. Place the centrifuge tubes in 50℃ water for 10 minutes, then remove and shake for 3 minutes;

[0094] c. Place in a centrifuge and centrifuge at 4500g for 10 minutes to allow insoluble matter to precipitate. Discard the supernatant and wipe the tube wall clean with a cotton swab.

[0095] d. Add 38 mL of water at 50°C, stopper the container, and shake up and down to suspend the precipitate.

[0096] e. Centrifuge at 4500g for 10 minutes, discard the supernatant, and carefully wipe the tube wall with a cotton swab.

[0097] f. Dry in a 60℃ oven until constant weight (the difference between the last two weight measurements should not exceed 2mg). Calculate the solubility based on the initial moisture content of the whey protein powder. The formula for calculating the solubility is as follows:

[0098] Where X represents the solubility of whey protein powder, in g / 100g; m1 represents the mass of the dried precipitate, in g; B represents the initial moisture content of the whey protein powder, in g / 100g; and m0 represents the mass of the whey protein powder, in g.

[0099] ② Hydrated particle size:

[0100] a. Prepare a 3% protein content solution, stir at 50°C for 30 minutes, cool to 25°C and hydrate for 1 hour;

[0101] b. The particle size of whey protein was tested using a Mastersizer 3000 laser particle size analyzer with the following parameters: material refractive index 1.47, absorptivity 0.01; dispersant refractive index 1.33; test refractive index 10%, stirring speed 2000 rpm.

[0102] ③ Gel strength:

[0103] a. Prepare a 10% protein content solution, stir at 50℃ for 30 min, hydrate at 25℃ for 30 min, and homogenize at a first-stage pressure of 150 bar and a second-stage pressure of 30 bar.

[0104] b. Heat at 80℃ for 45 minutes, cool to 25℃ in an ice water bath, and incubate overnight at 4-7℃.

[0105] c. Measuring gel strength: Weak gel test:

[0106] pre-test:1.0, test:0.5, post-test:10, distance:20, trigger force:2.

[0107] ④ Acid-heat particle size

[0108] a. Prepare a protein solution with a protein content of 3.8%, dissolve it in water at 45°C for 30 minutes by stirring, hydrate it at 25°C for 30 minutes, and then homogenize it (first-stage pressure is 150 bar, second-stage pressure is 30 bar);

[0109] b. Heat to 85℃, keep warm for 7 minutes, then cool rapidly in an ice water bath to 42℃;

[0110] C. Add lactic acid, adjust the pH to 4.4±0.1, heat to 75℃, keep warm for 2 minutes, cool rapidly in an ice water bath, let stand at 25℃ for 1 hour to equilibrate, and then measure the particle size. The parameter settings are the same as ②-b.

[0111] Table 2 summarizes the characteristic indicators of whey protein raw materials.

[0112] Table 2

[0113] (3) Data statistical analysis

[0114] Cluster analysis was performed on all data using the Excel add-in XLSTAT 2019. The clustering results are shown in Figure 1. The 18 whey protein raw materials were divided into 4 categories, and the classification results are shown in Table 3.

[0115] Table 3

[0116] Comparing their characteristic index data, type ① proteins exhibit the highest gel strength, indicating that they form a gel network structure and enhance product texture. Therefore, type ① proteins are named "texture-enhancing proteins." The value ranges for a, b, c, and d in this category are: 96 ≤ a ≤ 100, 0 ≤ b ≤ 22, 170 ≤ c ≤ 1200, and 28 ≤ d ≤ 140. Type ② proteins, with only one sample, are highly soluble in water and have extremely small particle sizes after hydration. Their large particle size under acid and heat indicates poor acid and heat stability, but they do not form a gel, consistent with the characteristics of isolated whey protein. Therefore, they are named "isolated proteins." The value ranges for a, b, c, and d in this category are: 99 ≤ a ≤ 100, and 0 ≤ b ≤ 0.1. c=0, 110≤d≤140; ③ type of protein has the worst solubility and the highest hydrated particle size. The small acid-heat particle size indicates high acid-heat stability and it cannot form a gel, which is consistent with the characteristics of micronized whey protein. Therefore, it is named "micronized protein". The value range of a, b, c, d for this type is: 15≤a≤55, 35≤b≤130, and when c=0, 1≤d≤22; ④ type of protein has four dimension characteristic index values ​​between ① texture-enhanced type and ③ micronized type. Its thermal stability is second only to ③ micronized type. Therefore, it is named "thermally stable protein". When the values ​​of a, b, c, d do not meet any of the above conditions, the whey protein powder belongs to the thermally stable type.

[0117] (4) Validation of whey protein raw materials

[0118] Six non-modeling whey proteins with different claimed functions were collected, and their solubility, hydrated particle size, gelation properties and acid-heat particle size were tested (summarized in Table 4). The data of the six new samples were merged with the data of 18 old samples and then cluster analysis was performed again to determine the category to which the six new raw material samples belong.

[0119] Table 4

[0120] The cluster analysis results are shown in Figure 2. E and F were classified into class ① texture-enhancing proteins, C was classified into class ② separation proteins, A and B were classified into class ③ microparticle-type proteins, and D was classified into class ④ thermostable proteins.

[0121] (5) Validation of the yogurt model system

[0122] To verify the effects of different types of whey protein powder on the yogurt system, raw material samples 1#-18# were used to verify the yogurt model system.

[0123] a. Prepare liquid milk with 3.6% protein content using milk with 3.2% protein content and various types of whey protein powder:

[0124] b. Preheat milk to 45°C, add whey protein powder, shear and dissolve for 30 minutes, sterilize at 85°C for 10 minutes, cool to 42°C and inoculate for fermentation.

[0125] c. Ferment until pH = 4.30-4.40, at which point the emulsion breaks down.

[0126] d. Sensory testing of yogurt models: descriptive testing;

[0127] The sensory evaluation included a preference test where 10 professionally trained panel tasters scored the product's flavor and texture. Based on the sensory evaluation results, principal component analysis was performed on the yogurt sample data using the Excel add-in XLSTAT 2019, as shown in Figure 3.

[0128] The results showed that adding type ① whey protein to yogurt products resulted in a sticky and thick texture, even a powdery feel, which is directly related to its textural enhancement properties. Adding type ② whey protein to yogurt also resulted in a sticky, thick, and powdery texture, even exhibiting a granular surface. This is directly related to the high content of active proteins in the isolated whey protein; more active whey proteins participate in the formation of the yogurt structure, making the yogurt gel network less susceptible to shearing and agitation, thus resulting in visible gel particles. Types ③ and ④ were closely related and both exhibited smooth and refreshing characteristics in yogurt applications. This is directly related to the strong acid-thermal stability of these proteins and their tendency to not form gels or form weak gels. It is speculated that these proteins do not participate in or minimally participate in the formation of the yogurt gel network, but rather are embedded in the pores of the yogurt network in an inert filling manner. Therefore, they do not increase the strength of the product's texture, but instead give the product a smooth and refreshing quality. Compared to ④, type ③ imparts a stronger smoothness to the product, but has poorer stability.

[0129] (6) Recommendations for Raw Material Application

[0130] Based on the texture and taste of yogurts with different types of whey protein added, recommendations are made for the application scenarios of the ingredients, as summarized in Table 5.

[0131] Table 5

[0132] (7) Introduction of new whey protein raw materials

[0133] When a new whey protein raw material is introduced again, its solubility (a), hydrated particle size (b), gel strength (c), and acid-heat treated particle size (d) are measured. By comparing its numerical range or integrating it with the data in Example 1 and performing cluster analysis, the textural functions of the new raw material can be classified and identified, and application recommendations for the new raw material can be output.

[0134] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for classifying the textural functions of whey protein powder, characterized in that, The classification method includes: The solubility (a), hydrated particle size (b), gel strength (c), and acid-heat treated particle size (d) of whey protein powder were tested and classified according to the following standards: When 96≤a≤100, 0≤b≤22, 170≤c≤1200, and 28≤d≤140, whey protein powder belongs to the texture-enhanced type. When 99≤a≤100, 0≤b≤0.1, c=0, and 110≤d≤140, whey protein powder belongs to the isolated type; When 15≤a≤55, 35≤b≤130, and c=0, and 1≤d≤22, whey protein powder belongs to the micronized type. When the values ​​of a, b, c, and d do not meet any of the above conditions, the whey protein powder is heat-stable.

2. The classification method according to claim 1, characterized in that, The solubility test method includes: mixing whey protein powder and water, centrifuging to remove the supernatant, drying the precipitate to constant weight, and calculating the solubility based on the initial water content of the whey protein powder; the formula for calculating the solubility is as follows: Where X represents the solubility of whey protein powder, in g / 100g; m1 represents the mass of the dried precipitate, in g; B represents the initial moisture content of the whey protein powder, in g / 100g; and m0 represents the mass of the whey protein powder, in g. The mixing temperature is 45-55℃.

3. The classification method according to claim 1 or 2, characterized in that, The method for testing the hydrated particle size includes: mixing whey protein powder and water, allowing it to stand for hydration, and then testing the particle size. The mixing temperature is 45-55℃, and the mixing time is 20-40 minutes; The hydration temperature is 20-30℃, and the hydration time is 0.5-1.5h.

4. The classification method according to any one of claims 1-3, characterized in that, The method for testing gel strength includes: mixing whey protein powder and water, allowing it to stand for hydration, then homogenizing, heating and cooling, and then testing the gel strength. The mixing temperature is 45-55℃, and the mixing time is 20-40 minutes; The hydration temperature is 20-30℃, and the hydration time is 20-40 minutes; The primary pressure of the homogenization is 100-200 bar, and the secondary pressure of the homogenization is 20-40 bar. The heating temperature is 80-90℃, and the heating time is 40-50 minutes; The temperature is cooled to 20-30℃.

5. The classification method according to any one of claims 1-4, characterized in that, The method for testing the particle size after acid heat treatment includes: mixing whey protein powder and water, allowing it to stand for hydration, then homogenizing, and cooling after a first heating; adding an acidic reagent to adjust the pH, and cooling after a second heating, and then testing the particle size.

6. The classification method according to claim 5, characterized in that, The mixing temperature is 40-50℃, and the mixing time is 20-40 minutes; The hydration temperature is 20-30℃, and the hydration time is 20-40 minutes; The primary pressure of the homogenization is 100-200 bar, and the secondary pressure of the homogenization is 20-40 bar. The temperature of the first heating is 80-90℃, and the heating time is 5-10 minutes; The first heating is followed by cooling to a temperature of 38-45℃; The acidic reagent includes any one or a combination of at least two of lactic acid, citric acid, or hydrochloric acid; The pH is adjusted to 4.3-4.5; The second heating temperature is 70-80℃, and the second heating time is 0.5-5 minutes; The second heating is followed by cooling to a temperature of 20-30℃.

7. A classification model for the textural function of whey protein powder, characterized in that, The classification model includes a detection unit and an analysis unit; The detection unit includes tests for the solubility (a), hydrated particle size (b), gel strength (c), and acid-heat treated particle size (d) of whey protein powder. The analytical unit includes a classification system that performs textural functions on whey protein powder, and the classification criteria include: When 96≤a≤100, 0≤b≤22, 170≤c≤1200, and 28≤d≤140, whey protein powder belongs to the texture-enhanced type. When 99≤a≤100, 0≤b≤0.1, c=0, and 110≤d≤140, whey protein powder belongs to the isolated type; When 15≤a≤55, 35≤b≤130, and c=0, and 1≤d≤22, whey protein powder belongs to the micronized type. When the values ​​of a, b, c, and d do not meet any of the above conditions, the whey protein powder is heat-stable.

8. A method for constructing a classification model of the textural function of whey protein powder according to claim 7, characterized in that, The construction method includes the following steps: (1) Detect the raw material characteristics of whey protein powder; (2) Perform cluster analysis on the data information obtained in step (1) and obtain a classification model of whey protein powder texture function based on the analysis results; (3) Take whey protein powder to verify the classification model obtained in step (2).

9. The construction method according to claim 8, characterized in that, The raw material characteristics mentioned in step (1) include a combination of solubility, hydrated particle size, gel strength and acid heat treatment particle size.

10. A classification model system for the textural function of whey protein powder, characterized in that, The classification model system includes a processor; and A memory storing a program, the program containing instructions that, when executed by the processor, cause the processor to perform the method according to any one of claims 1-6.

11. A classification model system for the textural function of whey protein powder, comprising a detection unit and an analysis unit; The detection unit is configured to perform tests on the solubility (a), hydrated particle size (b), gel strength (c), and acid-heat treated particle size (d) of whey protein powder. The analysis unit is configured to perform textural classification of whey protein powder, and the classification criteria include: When 96≤a≤100, 0≤b≤22, 170≤c≤1200, and 28≤d≤140, whey protein powder belongs to the texture-enhanced type. When 99≤a≤100, 0≤b≤0.1, c=0, and 110≤d≤140, whey protein powder belongs to the isolated type; When 15≤a≤55, 35≤b≤130, and c=0, and 1≤d≤22, whey protein powder belongs to the micronized type. When the values ​​of a, b, c, and d do not meet any of the above conditions, the whey protein powder is heat-stable.

12. The application of a method for classifying the textural functions of whey protein powder according to any one of claims 1-6, a classification model for the textural functions of whey protein powder according to claim 7, or a classification model system according to claim 10 or 11 in the development of dairy products.

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