A new whey protein ingredient

Abstract

To provide a new whey protein material containing modified MP (microparticulated) whey having the functions of suppressing the syneresis of acidophilus milk gel such as fermented milk and yogurt and increasing the hardness.SOLUTION: Whey solution containing lactose of 20 wt.% or more is subjected to heating and shearing, resulting in aggregation of modified MP whey.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a novel whey protein material. [Background technology]

[0002] Whey, a by-product of cheese and casein production from animal milk such as cow's milk, contains lactose, minerals, and whey protein. Whey protein is recognized as a high-quality protein source, and whey protein ingredients such as WPC (Whey Protein Concentrate) and WPI (Whey Protein Isolate) are manufactured and sold by concentrating whey using an UF membrane to increase the whey protein concentration and reduce the lactose and mineral concentrations. In recent years, microparticulated (MP) whey ingredients and manufacturing equipment have been marketed, taking advantage of the heat-induced denaturation and aggregation of whey protein. MP whey is generally whey protein aggregates with a volume-based median diameter of 0.5–10 μm, which are precipitated by centrifugation at 5,000–15,000 g.

[0003] Patent Document 1 discloses a method for producing MP whey, which can be used as a substitute for fat, by subjecting whey protein to a heat shear treatment. Non-Patent Document 1 reports on the effects of lactose and heating temperature during preparation of MP whey on the particle size, structure, and water retention of MP whey. It states that preparation at a high lactose concentration changes the structure of MP whey and increases its water retention, but only examines a whey solution with a lactose concentration of 13.5% by weight.

[0004] WPC and WPI are generally used to inhibit syneresis and impart hardness to fermented milk, yogurt, etc., but Non-Patent Documents 2 and 3 report that a sour milk gel containing 5% by weight of casein has lower hardness and dynamic viscoelasticity than a sour milk gel containing 2.5% by weight of casein and 2.5% by weight of MP whey. From this, it can be said that it is generally known that MP whey does not have the syneresis inhibition or hardness imparting effect of WPC and WPI, and instead reduces hardness. Patent Document 2 discloses fermented milk that is stable to vibration and has little syneresis using partially heat-denatured whey protein, and a method for producing the same. Both partially heat-denatured whey protein and MP whey are produced by flocculating whey protein through heating. However, while MP whey has a volume-based median diameter of 0.5 to 10 μm and precipitates upon centrifugation at 5,000 g to 15,000 g, partially heat-denatured whey protein is a soluble aggregate with a small particle size that does not precipitate even at 15,000 g. Therefore, the physical structure of partially heat-denatured whey protein differs from that of MP whey. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Application No. Hei 3-510449 [Patent Document 2] Japanese Patent Application Publication No. 9-94059 [Non-patent literature]

[0006] [Non-Patent Document 1] International Journal of Food Science and Technology, 34 (1999) p523-531 [Non-patent document 2] International Dairy Journal, 59 (2016) p1-9 [Non-patent document 3] International Dairy Journal, 62 (2016) p43-52 Summary of the Invention [Problem to be solved by the invention]

[0007] As mentioned above, MP whey is generally produced by denaturing and coagulating whey protein through heating, but its use has been limited to its use as a fat substitute. However, non-fat fermented milk has traditionally had the problem of needing to prevent syneresis and retain its shape. If MP whey could be given the previously unseen functions of syneresis inhibition and increased hardness, it is believed that it would become a whey protein material with new functionality that would solve this problem.

[0008] The object of the present invention is to provide a whey protein material having unprecedented characteristics, which contains MP whey that has the function of inhibiting syneresis and increasing hardness of sour milk gels such as fermented milk, and a method for producing the same. [Means for solving the problem]

[0009] In order to solve the above problems, the present invention includes the following configurations. [1] A method for producing a whey protein material containing MP whey, which comprises heating and shearing a whey solution containing 20 to 40% by weight of lactose. [2] The method for producing a whey protein material according to [1], wherein the protein content of the whey solution is 5% by weight or more. [3] The method for producing a whey protein material according to [1] or [2], wherein the whey solution further contains calcium at a concentration of 0.005% by weight or more per 1% by weight of whey protein. [4] The method for producing a whey protein material according to any one of [1] to [3], wherein the whey solution is heated to 70°C or higher. [5] A liquid whey protein material containing 66 to 80% by weight of lactose and 16 to 31% by weight of MP whey per total solid content, wherein the median diameter of the MP whey is 5 μm or less. [6] A powdered whey protein material containing 66 to 80% by weight of lactose and 16 to 31% by weight of MP whey per total solid content, wherein the median diameter of the MP whey is 5 μm or less. [7] Fermented milk containing whey protein material [5] or [6]. [Effects of the Invention]

[0010] The present invention can provide a whey protein material with unprecedented characteristics, which contains MP whey that has the function of inhibiting syneresis and increasing hardness in fermented milk, yogurt, etc., and a method for producing the same. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 shows the water retention capacity of the lactic acid gels produced in Examples 1 to 3 and Comparative Examples 1 and 2. [Figure 2] FIG. 2 shows the hardness of the lactic acid gels produced in Examples 1 to 3 and Comparative Examples 1 and 2. DETAILED DESCRIPTION OF THE INVENTION

[0012] The whey protein material according to an embodiment of the present invention will be described in detail below. (Whey Protein) The raw material, whey protein, is found in animal milk such as cow's milk. Whey solution containing whey protein is obtained as a by-product of natural cheese and casein production. Concentrated whey solution is obtained through a process that removes fat and casein fines from the whey solution, and a process that removes ash and lactose using membranes or ion exchange resins to concentrate the whey protein. WPC and WPI are then obtained by spray drying or freeze drying.

[0013] When producing the whey protein material of the present invention, the above-mentioned liquid concentrated whey solution may be used, or commercially available WPC or WPI may be reduced to a solvent such as water and used. The protein content in the whey solution is preferably 5% by weight or more, and most preferably 10% to 20% by weight. In the present invention, the whey solution used to produce MP whey, which has the function of inhibiting syneresis and increasing hardness of acid milk gel, is characterized by containing a high concentration of lactose, and the lactose concentration in the whey solution is preferably 20% by weight or more, more preferably 30% by weight or more, and most preferably about 40% by weight. The whey solution preferably contains calcium, and the calcium concentration in the whey solution should be 0.005% by weight or more relative to 1% by weight of whey protein. The presence of calcium at this level in the whey solution causes the whey protein to rapidly aggregate when the whey solution is heated, and by applying shear to this aggregate, it can be converted into the form of MP whey. Any food-grade lactose can be used in the present invention. The calcium material used in the present invention may be any food material, and examples thereof include calcium chloride, calcium lactate, calcium phosphate, etc., with calcium chloride being preferred.

[0014] (Whey protein modification treatment) The whey solution is heated and sheared. Heating may be performed to any temperature at which the whey protein denatures and aggregates, preferably 70°C or higher, more preferably 80°C or higher, and most preferably 90°C or higher. Shearing can be performed using a commercially available high-pressure homogenizer or the like. It can also be performed using a device capable of simultaneous heating and shearing, such as a scraping-type sterilizer. As long as it can perform heating and shearing, the device is not particularly limited to the above. By this modification treatment, the whey protein becomes modified MP whey.

[0015] (New whey protein material) The whey solution obtained by the modification treatment can be used as is in fermented milk, yogurt, etc., or can be powdered by spray drying or freeze drying. Furthermore, the MP whey modified by the above treatment is a precipitate fraction obtained by centrifuging a whey solution that has been subjected to a heat shear treatment, and it is also possible to remove soluble substances such as lactose and ash and use only the MP whey fraction. That is, the novel whey protein material of the present invention may be a whey solution containing MP whey that inhibits syneresis and increases the hardness of sour milk gel, or the MP whey powdered by spray drying or freeze drying, or a fraction of the MP whey from which soluble substances such as lactose and ash have been removed by centrifugation.

[0016] Specifically, the whey protein material of the present invention is a liquid or powdered whey protein material that contains 66 to 80% by weight of lactose and 16 to 31% by weight of MP whey based on the total solid content, and the MP whey has a median diameter of 5 μm or less. The MP whey contained in the whey protein material of the present invention preferably has a volume-based median diameter of 0.5 to 5 μm, most preferably 0.5 to 3.0 μm.

[0017] As will be apparent from the examples and comparative examples described below, the novel whey protein material produced by the production method of the present invention is characterized in that the MP whey contained therein has a structure with appropriate flexibility and porosity. The inventors of the present invention presume that this is due to the following mechanism, but the present invention should not be construed as being limited by such presumption. That is, the present invention is characterized by employing a modification method in which a whey solution containing lactose at a specific concentration is subjected to heating and shearing. Normally, when a whey solution is heated and sheared, the whey proteins denature and aggregate depending on the degree of heating and shearing. However, when an appropriate concentration of lactose is present in the whey solution, the lactose acts to inhibit the denaturation and aggregation of whey proteins caused by heat and shearing. As a result, the modified MP whey, unlike regular MP whey, becomes an aggregate with moderate flexibility and porosity. It is believed that when the modified MP whey of the present invention is added to fermented milk, it is incorporated into the casein curd network in the fermented milk through hydrophobic interactions, reinforcing the network. Therefore, it is speculated that the MP whey of the present invention has appropriate flexibility and water retention properties, which improves the hardness and water retention properties of the casein curd in the fermented milk.

[0018] The novel whey protein material produced in this manner is a liquid or powdered whey protein material containing 66 to 80% by weight of lactose and 16 to 31% by weight of MP whey based on the total solid content, with the MP whey having a median diameter of 5 μm or less. [Example]

[0019] The present invention will be described below with reference to examples, but the present invention should not be construed as being limited to these examples. [Example 1] (1) Preparation of whey solution WPI was reduced to a concentration of 10% by weight, and lactose was added to final concentrations of 10%, 20%, 30%, and 40% by weight. Calcium chloride was added to a final concentration of 0.05% by weight. (2) Heat shear treatment The whey solution was sheared while being heated at 90°C. The particle size distribution (volume-based median diameter) of the whey solution and the MP whey content in the total protein were measured. The MP whey fraction was calculated by centrifuging the heated whey solution at 15,000 g and measuring the protein concentration in the supernatant.

[0020] The lactose concentration in the obtained whey solution, the MP whey content in the total protein, and the volume-based median diameter of the MP whey are as shown in Table 1. [Table 1]

[0021] As is clear from the results in Table 1, the MP whey concentration and median diameter of total protein decreased with increasing lactose concentration. This is because lactose inhibits the denaturation or aggregation of whey proteins due to heating. The resulting modified MP whey is thought to have a moderately porous structure compared to MP whey subjected to heat shear in the presence of low concentrations (including 0) of lactose.

[0022] The concentrations per solid content of lactose and MP whey and the volume-based median diameter of MP whey converted from the data in Table 1 are shown in Table 2. These whey protein materials were added to acid milk gel to confirm their effects. [Table 2]

[0023] (3) Preparation of acid milk gel Skim milk powder was reconstituted in water to a concentration of 10% by weight. The MP whey solutions shown in Tables 1 and 2 were centrifuged to remove soluble protein and lactose, and the precipitate was collected and resuspended in distilled water. This procedure was repeated five times. Each level of MP whey was added to the reconstituted skim milk at 1.0% by weight in terms of protein. 1.5% by weight of glucono-δ-lactone was added to prepare a sour milk gel.

[0024] (4) Evaluation of acid milk gel The hardness and water retention of the acid milk gel were measured. Hardness was defined as the maximum load. The maximum load was measured by a penetration test of the acid milk gel using a texture analyzer. Specifically, the maximum load was measured by subjecting a sample adjusted to 10°C to the texture analyzer at a measurement speed of 1 mm / sec, a penetration distance of 10 mm, and using a resin cylindrical probe with a diameter of 16 mm and a height of 25 mm. The sample size was sufficient as long as it had a height of at least 10 mm, which is the penetration distance, and a diameter of at least 16 mm. The water retention capacity was calculated from the weight of the supernatant on the sour milk gel card and the weight of the original sour milk gel card after preparing the sour milk gel in a centrifuge tube and centrifuging it at 2000 g for 10 minutes. Specifically, it was calculated using the following formula: Water retention capacity of acid milk gel = (1 - (weight of supernatant) / weight of acid milk gel curd) x 100%

[0025] As a result, as shown in Figure 1, the acid milk gels containing modified MP whey in Examples 1 to 3 had higher water retention than Comparative Example 1, which did not contain lactose. In particular, Example 3 had significantly higher water retention than Comparative Example 2. On the other hand, as shown in Figure 2, only Example 3 had a significantly higher hardness than Comparative Examples 1 and 2. The modified MP whey of Example 3 particularly increased the water retention and hardness of the acid milk gel, which may contribute to the formation of a casein network.

[0026] These experimental results revealed that the whey protein materials in Examples 1 to 3 are liquid whey protein materials containing 66 to 80% by weight of lactose and 16 to 31% by weight of MP whey per total solid content, and the MP whey has a median diameter of 5 μm or less, and have the function of inhibiting syneresis and increasing the hardness of acid milk gel. Furthermore, the powdered whey protein material obtained by powdering the liquid whey protein material contains the same proportions of lactose and MP whey per total solids as the liquid whey protein material, and the median diameter of the MP whey is also the same. Therefore, when added to an acidic milk gel, the powdered whey protein material similarly inhibits syneresis and increases the hardness of the acidic milk gel.

Claims

1. A liquid whey protein material contains 66 to 80% by weight of lactose and 16 to 31% by weight of MP whey based on the total solid content, with the MP whey having a median diameter of 5 μm or less, and is obtained by heating at 70° C. or higher and shearing a whey solution containing 5% by weight or more of protein, 20 to 40% by weight of lactose, and 0.005% by weight or more of calcium per 1% by weight of whey protein.

2. A powdered whey protein material containing 66 to 80% by weight of lactose and 16 to 31% by weight of MP whey based on the total solid content, the MP whey having a median diameter of 5 μm or less, is obtained by heating at 70° C. or higher and shearing a whey solution containing 5% by weight or more of protein, 20 to 40% by weight of lactose, and 0.005% by weight or more of calcium per 1% by weight of whey protein.

3. Fermented milk containing the whey protein material according to claim 1 or 2.

Images