JP4795180B2 - Dairy beverage having a new texture and method for producing the same - Google Patents

Description

Background of the Invention

FIELD OF THE INVENTION The present invention relates to a dairy beverage having a novel texture (texture) and a method for producing the same.

Background Art Beverages made from milk (hereinafter sometimes referred to as “milk drinks” in this section), represented by milk drinks, have a texture that makes them feel somewhat viscous due to suspension and emulsification of proteins and lipids. Have Such a texture of milk beverages gives a clear added value to the product. For this reason, dairy beverages that can be expected to have such a texture and are rich in milk ingredients are generally sold at relatively high prices. However, since dairy ingredients themselves are never cheap, it is becoming difficult to provide consumers with milk drinks that use such dairy ingredients in abundant price.

  Therefore, without increasing the amount of dairy ingredients used, the texture is similar to that of milk beverages that are rich in dairy ingredients. The development of dairy beverages that can be expressed has been studied.

  For example, it is conceivable to improve the texture by imparting a slight viscosity to the dairy beverage by devising the selection of the milk raw material such as using sweetened condensed milk when preparing the dairy beverage. However, the level of viscosity that can be achieved by selection of such raw materials is not always satisfactory.

  In addition, it is conceivable to use a thickening polysaccharide such as carrageenan, guar gum, locust bean gum or the like to impart viscosity to a dairy beverage and improve its texture. However, the use of such additives is not a sufficient solution from the viewpoint of providing high-value-added dairy drinks because it gives consumers a sense of discomfort.

  Therefore, it has been studied to change the physical properties of the entire beverage by applying thermal or mechanical energy to the protein component in the beverage.

  For example, in Japanese translations of PCT publication No. 2003-535609 (Patent Document 1), unmodified protein particles such as dairy protein are homogenized in an aqueous medium at pH 5.5 to 7.5 using a homogenizer under heating conditions. It is disclosed that, by increasing the average particle size of protein particles to about 0.1 to 5.0 microns, a soluble protein having a mouthfeel that can replace high-calorie fats and oils can be obtained. However, in the method disclosed here, it is necessary to further perform a heat sterilization treatment, and the physical properties and texture of the obtained protein-containing aqueous solution are different from those aimed by the present inventors. In this document, the viscosity of the protein-containing aqueous solution is not particularly examined.

  In Japanese translations of PCT publication No. 2004-518440 (Patent Document 2), an aqueous medium containing soy protein is adjusted to a pH of 7 to 7.5 and then subjected to heat treatment, whereby high molecular weight native protein aggregation is obtained. A method of forming an object is disclosed. However, the protein aggregate here is used as a component for obtaining a texture similar to the target meat product in a vegetarian meat analog (for example, a Frankfurt analog) or the like. For this reason, its use, as well as the intended physical properties and texture, are completely different from those aimed by the present inventors.

  JP-A-2005-185132 (Patent Document 3) discloses heating with pH of 4.6 to 5.4 (weakly acidic) by using pectin, gum arabic and citrate as a stabilizer. A low-viscosity dairy drink is described in which the protein does not agglomerate. However, this beverage uses an additive such as a stabilizer as described above, and since the protein does not aggregate, it is said that the viscosity is low. Are different.

  Accordingly, there is still a need to obtain a dairy drink having a “net-ri” texture while suppressing the amount of raw materials such as milk and without using additives such as thickeners. It can be said.

Special table 2003-535609 gazette JP-T-2004-518440 JP 2005-185132 A

Summary of the Invention

  The present inventors have now adjusted the pH of a mix (formulated milk) containing 3.0% or more of milk protein using a pH adjuster such as baking soda to increase the pH value, and heat-treating the mixture. The present inventors have found that a milk beverage product exhibiting an unprecedented characteristic texture (texture) and richness (brightness) can be obtained. At this time, a substantial increase in the viscosity of the milk beverage was actually observed, and it was found that the protein component in the milk beverage formed many large particles of about 10 μm. Furthermore, although this heat-treated milk protein is an aggregated solid, it is difficult to adhere to the heat transfer surface of the heat sterilizer and has excellent heat resistance (good heat stability). ) The present invention is based on such knowledge.

  Therefore, the present invention is a “netry” that makes a slight viscosity feel without using thickening polysaccharides and other additives by extracting the inherent properties of milky (milky) materials. It is an object of the present invention to provide a milky beverage having a texture and a method for producing the same.

  The dairy beverage according to the present invention comprises at least 3.0 to 12% by weight of food protein and has been previously subjected to pH adjustment treatment for increasing the pH value of the aqueous medium by 0.1 to 1.2. It is obtained by heat-treating a pH-adjusted food protein-containing aqueous solution under heat sterilization conditions.

  Moreover, the manufacturing method of the dairy drink which has the novel food texture accompanying the viscosity increase by this invention comprises at least 3.0-12 weight% food protein, and the pH value of an aqueous medium is 0.1. ~ 1.2 Increasing pH-adjusted food protein-containing aqueous solution, which has been previously adjusted, by heat-treating under heat sterilization conditions, thereby obtaining a milky beverage having an increased viscosity Become.

  According to the present invention, by using the inherent properties of milk-like materials without using thickening polysaccharides and other additives, dairy beverages have a novel food texture, specifically Has a rich feeling and can maintain a “net-ri” texture that makes it feel a little viscous. For this reason, in the dairy drink by this invention and its manufacturing method, application, such as a physical property improvement of various foodstuffs, such as sauces, can be anticipated. Moreover, the milk protein heat-processed when manufacturing the milk drink of this invention becomes difficult to adhere to the heat-transfer surface etc. of a heat sterilizer, although it has become the aggregated solid substance. That is, it can be said that the milk beverage according to the present invention has high heat resistance (good heat stability). For this reason, according to the method of the present invention, it is possible to reduce the possibility of an abnormality such as scorching on the plate surface of the heat transfer surface, so that the product can be manufactured stably and efficiently. Therefore, it can be said that the method according to the present invention is a method having excellent practicality.

Detailed description of the invention

Milk beverage In the present invention, a milk beverage means a beverage containing at least a component that uses milk or soy milk (preferably milk) as a raw material, a component derived from milk or dairy products such as raw milk and skim milk powder, or It will not specifically limit if it contains the component derived from soymilk or a soymilk product as a main raw material. For example, the dairy beverage according to the present invention includes a milk beverage supplemented with minerals such as vitamins, calcium and iron, a coffee milk beverage, a fruit milk beverage, such as a nutrient-added milk beverage and a flavored milk beverage, Similar types of soy milk beverages such as chocolate milk beverages, modified soy milk, and soy protein beverages are included. Moreover, the dairy beverage may further contain other additional components such as a sweetener, a sour agent, a flavoring agent, a coloring agent, and lactic acid bacteria in addition to the main raw material. Therefore, the dairy drink is not limited to the “milk drink” defined by the so-called ministerial ordinance of milk, and may include fermented milk, lactic acid bacteria drink, and the like.

  Examples of milk or dairy products that can be used as a main ingredient include skim milk powder, whole milk powder, partially skim milk powder, skim milk, concentrated milk, butter, cream, and mixed milk (mixed). If it is a raw material, it will not specifically limit. The soy milk or soy milk product that can be the main raw material is particularly limited as long as it is a milky beverage obtained by soaking soybeans in water and then ground, heated and filtered, and a product made through such a process. For example, tofu is also included.

Food protein-containing aqueous solution As described above, the dairy beverage according to the present invention contains at least a specific amount of food protein, and the pH value of the aqueous medium is adjusted in advance. The aqueous solution is obtained by heat treatment under heat sterilization conditions.
In the present invention, an aqueous solution containing milk protein is referred to as a “food protein-containing aqueous solution”, and a solution whose pH is adjusted is referred to as a “pH-adjusted food protein-containing aqueous solution”. .

  In the present invention, food protein refers to a protein selected from the group consisting of milk protein, soy protein, and mixtures thereof. Here, milk protein refers to protein present in milk or dairy products, and the amount (concentration) of protein is easily measured by a conventional method or apparatus such as Kjeldahl method, Raleigh method, etc. be able to. In addition, soy protein refers to protein present in soy milk or soy milk product, and the amount (concentration) of milk protein can be easily measured in the same manner as milk protein.

  The concentration of food protein in the food protein-containing aqueous solution is 3.0 to 12% by weight (based on the weight of the aqueous solution) as described above. When the concentration of the food protein is within such a range, it is advantageous for obtaining a beverage having desired physical properties and texture. For example, if the concentration is too low, the viscosity increase to such an extent that the eater can feel the desired texture hardly occurs even when the heat treatment is performed. The concentration of food protein is preferably 3.3 to 10% by weight, more preferably 3.3 to 8% by weight. At a level exceeding 3.3% by weight, a very rich texture can be obtained in the produced milk beverage.

  In the present invention, the food protein is preferably composed of milk protein. However, within the range where the “net texture” characteristic of the present invention is expressed by heat treatment, a part of milk protein or All can be replaced with soy protein. It will be readily understood by those skilled in the art that the effects of the present invention can be obtained even when part or all of milk protein is replaced with soy protein. When a part of milk protein is replaced with soy protein, that is, when a mixture of milk protein and soy protein is used as food protein, the mixing ratio is not particularly limited, but the case where milk protein is the main component is preferable. It can be illustrated as an aspect. Furthermore, in the present invention, in addition to the food protein, other proteins (for example, egg protein) may be further used as long as the “net texture” characteristic of the present invention is expressed. good.

  In the present invention, before subjecting the food protein-containing aqueous solution to heat treatment under heat sterilization conditions, a pH adjustment treatment is performed in advance to increase the pH value of the aqueous medium of the aqueous solution by 0.1 to 1.2. It is important that That is, for the heat treatment, it is important to use a food protein-containing aqueous solution whose pH has been adjusted. Here, after the food protein-containing aqueous solution is adjusted, the pH adjustment treatment may be performed on the obtained aqueous solution. However, the milk protein prepared for preparing the food protein-containing aqueous solution and the aqueous medium are prepared. (Usually water) before or simultaneously with the aqueous medium. For example, as will be described later, when the pH adjustment treatment is performed by adding a pH adjuster, the pH value of milk protein and the target aqueous solution (or aqueous medium) is increased by 0.1 to 1.2. An effective amount of the pH adjusting agent may be added simultaneously to the aqueous medium to obtain a pH-adjusted food protein-containing aqueous solution.

  In the present invention, even if the degree of increase of the pH value by adjusting the pH is slightly effective, it is actually recognized. For example, a sample that has been adjusted to pH 6.94 by adding 0.065% sodium bicarbonate (sodium bicarbonate) to a mix having a pH of 6.82 before pH adjustment has been found to have a sufficient viscosity increase due to heat treatment. ing.

  As described above, in the present invention, it is not important to set the absolute value of the pH of the aqueous solution within a specific region, but a pH shift (specifically, a pH value of 0 in the aqueous solution by adjusting the pH under a predetermined condition). The present inventors consider that it is important to make an increase of about .1 to 1.2). Here, it is considered that the pH shift is effectively performed in an aqueous solution containing milk protein. However, milk protein that is usually used as a raw material for dairy beverages (usually used by those skilled in the art) and water as an aqueous medium are used as they are, and subjected to heat treatment by subjecting them to the above pH adjustment treatment. It is possible to anticipate and define the typical pH value of the food protein-containing aqueous solution in the previous state. In this case, in the present invention, the pH value of the pH-adjusted food protein-containing aqueous solution to be heat-treated is typically 6.5 to 8. When the pH value is within such a range, it is advantageous in changing the viscosity by heat treatment. Moreover, when pH value exceeds 8, the flavor as a milky drink will worsen and it may be unacceptable to a consumer. Therefore, the pH value of the pH-adjusted food protein-containing aqueous solution is preferably 6.6 to 7.8, more preferably 6.8 to 7.6.

  According to a preferred embodiment of the present invention, after adjusting a food protein-containing aqueous solution comprising at least a predetermined amount of food protein, a pH adjustment treatment is performed to increase the pH value of this aqueous solution by 0.1 to 1.2, A pH-adjusted food protein-containing aqueous solution is obtained. In this case, more preferably, the pH adjustment treatment is performed by adding a pH adjusting agent.

  Therefore, according to one preferred embodiment of the present invention, the method for producing a dairy beverage according to the present invention obtains a food protein-containing aqueous solution containing at least 3.0 to 12% by weight of milk protein, and has a pH of The method further comprises the step of obtaining a pH-adjusted food protein-containing aqueous solution by adding a conditioning agent to increase the pH value of the aqueous solution by 0.1 to 1.2.

  In the present invention, in the pH adjustment treatment, the pH value of the target aqueous solution (or aqueous medium) is 0.1 to 1.2, preferably 0.1 to 1.0, more preferably 0.1 to 0. The pH may be adjusted by any means as long as it can be increased within the range of .8. For example, an aqueous medium adjusted to have a higher pH value than that in a food protein-containing aqueous solution is prepared separately and added to increase the pH value of the resulting aqueous solution as described above. May be.

  In the present invention, the pH adjustment treatment is preferably performed using a pH adjuster. The pH adjuster that can be used here is not particularly limited as long as it can achieve the pH adjustment described above and has safety that can be used as a food. Typically, sodium bicarbonate, sodium hydroxide are used. , Selected from the group consisting of potassium hydroxide and sodium carbonate. These may be used in combination. According to a preferred embodiment of the present invention, the pH adjuster is sodium bicarbonate.

  When using a pH adjuster, the amount used is appropriately changed according to the type of pH adjuster to be used, the target pH value to be increased, the state of the aqueous solution to be added (for example, its temperature, pH, etc.), etc. For example, when sodium hydrogen carbonate is used as a pH adjuster, the amount used is typically defined as a concentration of 0.05 to 0.5% by weight, preferably 0.05 to 0%. .3% by weight.

In the present invention, in order to prepare a dairy beverage, the prepared food protein-containing aqueous solution is subjected to a heat treatment. In this case, the food protein-containing aqueous solution is usually homogenized. In the present invention, as shown in the Examples section described later, the homogenization treatment before and / or after the heat treatment is not an essential requirement for obtaining a desired dairy beverage, and the homogenization treatment is performed. Under these conditions, the increase in viscosity as expected in the present invention is not observed. For this reason, since a desired dairy drink can be obtained even when the homogenization treatment is not performed, in the present invention, the homogenization treatment before and / or after the heat treatment is performed as necessary. Just do it. In the case of performing the homogenization treatment, the homogenizer can be used, for example, heated to about 50 to 90 ° C. and under a condition of about 100 to 800 kg / cm ² .

  In the present invention, in order to prepare a dairy beverage, the pH-adjusted food protein-containing aqueous solution is heated. Here, the heat treatment corresponds to heat sterilization conditions. Usually, beverages made from milk or the like are sterilized by various methods before shipping as a product. The heat sterilization conditions of the heat treatment referred to here are one aspect of such a normal sterilization treatment. It means what is said. Therefore, the heat treatment in the present invention can be used without particular limitation as long as it is a heat sterilization treatment condition commonly used in the field of beverages and foods.

  However, in the present invention, it is necessary to consider the heat resistance (thermal stability) of the milk protein in the pH-adjusted aqueous solution as described in the examples described later. It is desirable that the range is not exceeded. Therefore, for example, the conditions for the heat treatment can be set such that excessive aggregation of milk proteins does not occur.

  According to a preferred embodiment of the present invention, the heat treatment is performed under conventional heat sterilization conditions well known to those skilled in the art, for example, by heating at 110 to 150 ° C. for 0.1 to 15 seconds. At this time, it is preferably 0.5 to 12 seconds at 120 to 150 ° C., more preferably 1 to 10 seconds at 125 to 145 ° C., further preferably 2 to 8 seconds at 125 to 145 ° C., particularly preferably. It is 2 to 5 seconds at 130 to 140 ° C.

In addition, a pressure may be applied to the aqueous solution during the heat treatment. Usually, when heat sterilization is performed, for example, the sterilization pressure is set to about 1 to 10 kg / cm ² for the purpose of preventing the aqueous solution from boiling. In the heat treatment in the present invention, such pressure may be applied in addition to heating.

  Since the present invention uses the heat sterilization treatment that is normally essential for the production of milky beverages in this way, it causes a thickening phenomenon in food protein-containing aqueous solutions and obtains the desired milky beverage. This process can be simplified, and can be said to be an advantageous method from the viewpoint of manufacturing efficiency and cost reduction.

  The dairy beverage according to the present invention has a novel texture and richness as a result of the heat treatment. As described above, the food texture can be functionally expressed as “netri” and is influenced by the amount (concentration) of fat or protein or the degree or state of protein aggregation. From the physicochemical aspect, for example, it is possible to grasp whether or not the beverage has achieved the desired texture in the present invention by increasing the viscosity as an index.

  Naturally, the viscosity of the milk beverage according to the present invention varies depending on the presence or absence of the ingredients other than food protein and the type thereof. For example, fat other than food protein is 0 to 15% by weight and lactose is 4%. When included at ˜20 wt%, the viscosity of the dairy beverage (food protein containing aqueous solution comprising at least 3.0 to 12 wt% food protein) is typically 7 to 50 mPa · s, Preferably it is 8-40 mPa * s, More preferably, it is 9-30 mPa * s. And the difference in viscosity before and after the heat treatment of the milk beverage according to the present invention is typically 2 to 30 mPa · s, preferably 3 to 20 mPa · s, more preferably 5 to 15 mPa · s. is there. Here, the viscosity can be measured, for example, with a tuning fork vibration type viscometer SV-10 (manufactured by A & D Co., Ltd.) (measurement temperature: 10 ° C.).

  As a specific example, skim milk powder and cream were prepared to contain 10.5% by weight of nonfat milk solids (about 3.6% milk protein) and 4.5% by weight of milk fat. Sodium bicarbonate 0.13% by weight was added to the food protein-containing aqueous solution, homogenized at 60 ° C (15 MPa), and then plate-type indirect heat sterilizer (plate-type sterilizer (Iwai Kikai Kogyo Co., Ltd.) at 140 ° C for 3 seconds. By the treatment by the company)), the viscosity before the heat treatment was 5.5 mPa · s and increased to 11.5 mPa · s, and at the same time a rich texture reminiscent of fat is expressed.

  In addition, the milk beverage according to the present invention typically forms giant particles of about 10 μm. Here, “about 10 μm” means that the average particle size of the protein component dispersed in the beverage as a result of aggregation of the protein in the milk beverage is about 10 μm, and is mainly in the range of about 5 to 50 μm. This means that a fine particle size distribution is observed. In the present invention, it is considered that this degree of protein aggregation also contributes to the unique texture of the milk beverage. Here, the particle diameter can be measured and determined using a laser diffraction particle size distribution analyzer SALD-2100 (manufactured by Shimadzu Corporation).

  In general, when an aqueous solution containing milk protein, particularly casein, is adjusted to pH 6 or less and subjected to heat treatment, protein aggregation is promoted and giant particles are formed. This is considered to be due to the fact that the electrical repulsion of casein is lost as it approaches pH 4.6, which is the isoelectric point of casein. Aggregation of protein obviously causes a change in texture, but the highly adherent aggregate adheres to a heat transfer surface such as a sterilizer plate, thereby preventing continuous heat sterilization treatment. In other words, a so-called “burning” phenomenon occurs, which causes a problem in the manufacturing process. On the other hand, according to the method of the present invention, although giant particles are still formed by heating, the adhesiveness thereof is extremely weak, so that continuous heat sterilization treatment is possible. In fact, as in the examples described later, a food protein-containing aqueous solution adjusted to a pH level of 6.75 to 7.00 is filled in a heat-resistant and pressure-resistant glass bottle and held in a 140 ° C. silicon oil thermostatic bath. Observing the adhesion to the glass surface and the particle size in the aqueous solution over time, the particle size increases with increasing pH, but the time until the adhesion to the glass surface gradually increases, The result which overturns common sense is obtained. It can be said that these points are also excellent effects of the present invention.

  In the present invention, food protein is an important factor for increasing the viscosity of dairy beverages. For this reason, the lipid itself is not an essential element. However, considering the preference as a beverage, it is preferable to further contain a lipid from the viewpoint of deliciousness. In addition, if the milk beverage contains a certain amount of lipid, it can be expected to prevent sedimentation of giant particles. This is because the inclusion of lipid in the giant particles reduces the specific gravity and suppresses sedimentation.

  In the present invention, the amount (concentration) of fat that can be contained is not particularly limited, but since normal milk or the like is used as a raw material, it may contain fat to the extent contained therein. Specifically, the concentration of fat is, for example, 0 to 14% by weight, preferably 0 to 7% by weight, more preferably 0 to 5% by weight, based on the food protein-containing aqueous solution before heating. is there. Here, concentrated milk etc. can be illustrated as a thing containing fat in high concentration, The application to not only dilute aqueous solutions, such as a milk drink, but a concentrated aqueous solution can also be anticipated.

  The milk beverage according to the present invention can further use other optional ingredients such as any food or food additive as ingredients other than food protein and fat. For example, sweeteners such as fragrances and sugars, pigments, stabilizers, preservatives, various proteins, trace elements, vitamins, and the like may be used as additives.

  In addition, the dairy beverage according to the present invention may be provided as a final product, but based on that, it is further processed into other foods (various sauces, etc.) and used as a raw material thereof. Can also be provided.

  The present invention will be described in detail with reference to the following examples, but the present invention is not limited thereto.

Example 1: [Effect of heating temperature, heating pressure, pH adjuster concentration and milk protein concentration on dairy beverage viscosity]
Preparations 1a to 1d shown in Table 1 below were prepared, and each of these preparations was applied to a pressure of 150 kg / cm ² (1st: 100 kg / cm ² , 2nd: 50 kg / cm) using a homogenizer (manufactured by Sanwa Kikai Co., Ltd.). cm ² ), the flow rate was 100 L / h, and the temperature was homogenized at 60 ° C. to prepare a milk protein-containing aqueous solution (formulated milk (mix)). Next, the milk protein-containing aqueous solution of each formulation was subjected to heat sterilization treatment (heating treatment) at a flow rate of 150 L / h using a plate type sterilizer (manufactured by Iwai Kikai Kogyo Co., Ltd.).
In this example and the following examples, studies were made using milk protein as an example of the food protein in the present invention.
In order to prepare each formulation, skim milk powder [milk fat content 1.0% by weight, nonfat milk solid content 95.5% by weight, and water content 3.5% by weight] (manufactured by Meiji Dairies), cream [milk Fat content 47.5 wt%, non-fat milk solid content 4.5 wt%, and moisture 48.0 wt%] (Meiji Dairies Co., Ltd.), and baking soda (sodium bicarbonate (food additive grade)) (Japanese Kogyo Pharmaceutical Co., Ltd.) was used.

Regarding the heat treatment conditions, the case where the heat sterilization temperature was set to 130 ° C. or 140 ° C. (both the heating time was 3 seconds) and the case where the sterilization pressure was set to 3 kg / cm ² or 5 kg / cm ² were examined. .

Before and after the heat treatment, milk protein-containing aqueous solutions of each formulation were collected and their viscosities were measured. The viscosity was measured using a tuning fork vibration viscometer SV-10 (manufactured by A & D Co., Ltd.) (measurement temperature: 10 ° C.). For the resulting viscosity, the rate of increase in viscosity was determined according to the following formula:
Viscosity increase rate [%] =
(Viscosity of sample after heat treatment) / (Viscosity of sample before heat treatment) × 100

In Table 1, formulations 1a to 1c correspond to comparative examples for the present invention. That is, Formulations 1a and 1b are cases where a pH adjuster (sodium bicarbonate (bicarbonate, NaHCO ₃ )) is not used (when no additive is added), and Formulations 1a and 1c have a milk protein amount of 3. This is the case when it is less than 0% by weight.

The results were as shown in Table 2.
The rate of increase in the viscosity of the resulting dairy beverage is affected by the concentration of the pH adjusting agent and the concentration of the milk protein, and it is determined by the three-way analysis of variance that the risk factor is 1% and there is a significant difference. It was. In addition, the results suggested that the concentration of the pH adjusting agent and the concentration of the milk protein may have a synergistic effect (interaction) on the increase in the viscosity of the dairy beverage.

Example 2: [Effect of Milk Protein Content (Concentration) on Viscosity of Milky Beverage]
The composition of each milk protein-containing aqueous solution is prepared in accordance with Table 3 below, and 2a to 2e are prepared. Further, as heat treatment conditions for the experiment, the heat sterilization temperature is 140 ° C. (heating time 3 seconds), and the sterilization pressure is 5 kg / The aqueous solution was homogenized and heat sterilized in the same manner as in Example 1 except that it was cm ² .
In addition, in the blending, the concentration of sodium hydrogen carbonate (sodium bicarbonate) was set to be in the range of 0.09 to 0.13% by weight, and the concentration of milk protein was the blending amount shown in the table. The total solid content to be added is adjusted.

  The milk protein-containing aqueous solution of each formulation was collected before and after the heat treatment, the viscosity was measured in the same manner as in Example 1, and the rate of increase in viscosity was calculated. Furthermore, a sensory evaluation test was conducted by 10 expert panelists on the texture of the milk protein-containing aqueous solution (that is, the milky beverage) after the heat treatment (in particular, the net feeling of the beverage).

The results were as shown in Table 4.
The increase rate of the viscosity of the milk beverage was affected by the concentration of the milk protein, and the increase rate of the viscosity increased with the increase of the concentration of the milk protein. Moreover, it was recognized that a viscosity increases with a heat sterilization process by making the density | concentration of milk protein or more into a predetermined value or more.

Example 3: [Influence on viscosity of dairy beverage by addition of pH adjusting agent]
The composition of each milk protein-containing aqueous solution is prepared according to Table 5 below, and 3a to 3d are prepared. Further, as heat treatment conditions for the experiment, the heat sterilization temperature is 140 ° C. (heating time 3 seconds), and the sterilization pressure is 5 kg / The aqueous solution was homogenized and heat sterilized in the same manner as in Example 1 except that it was cm ² .

  The milk protein-containing aqueous solution of each formulation was collected before and after the heat treatment, and the pH and viscosity thereof were measured in the same manner as in Example 1. The viscosity increase rate was further calculated. Furthermore, a sensory evaluation test was conducted by 10 expert panelists on the texture of the milk protein-containing aqueous solution (that is, the milky beverage) after the heat treatment (in particular, the net feeling of the beverage).

  In Table 5, Formulation 3a corresponds to a comparative example for the present invention. That is, Formulation 3a is a case where a pH adjuster (sodium hydrogen carbonate (bicarbonate)) is not used (when no additive is added).

The results were as shown in Table 6 and FIG.
From the results, the rate of increase in the viscosity of dairy beverages is affected by the pH adjustment by the pH adjuster, and the viscosity is increased with the heat sterilization treatment by increasing the concentration of the pH adjuster (bicarbonate) to a predetermined value or more. I found out that

Example 4: [Influence on viscosity of dairy beverage by type of pH adjuster]
The aqueous solution was homogenized and heat-sterilized in the same manner as in Example 3 except that the compositions 4a to 4e were used in accordance with Table 7 below for the composition of each milk protein-containing aqueous solution.
Here, as the pH adjuster, sodium carbonate (Na ₂ CO ₃ ), sodium hydroxide (NaOH), or potassium hydroxide (KOH) was used instead of sodium hydrogen carbonate. The concentration of the pH adjusting agent was set for each pH adjusting agent so that the pH of the sample before the heat treatment was about 6.9. Moreover, thereby, the ionic strength of the dairy drink prepared with each pH adjuster was different.

  The milk protein-containing aqueous solution of each formulation was collected before and after the heat treatment, and the pH, viscosity, and viscosity increase rate were obtained in the same manner as in Example 3. Further, the milk protein-containing aqueous solution (that is, milk) after the heat treatment was obtained. The sensory evaluation test was conducted in the same manner as in Example 3 with respect to the texture (especially the beverage's net feeling).

The results were as shown in Table 8.
From the results, the rate of increase in the viscosity of dairy beverages is not affected by the type of pH adjuster, and by increasing the concentration of each pH adjustor to a predetermined value or higher, the viscosity increases with heat sterilization treatment. I found out that

Example 5: [Effect of ionic strength on viscosity of milk beverage]
The homogenization of the aqueous solution and the heat sterilization treatment were performed in the same manner as in Example 3 except that the compositions 5a to 5d were used in accordance with Table 9 below for the composition of each milk protein-containing aqueous solution.
Of the pH adjusters used, NaHCO ₃ is alkaline (basic) and NaCl is neutral. In each formulation, the concentration of the pH adjusting agent was set for each pH adjusting agent so that the ionic strength of each sample aqueous solution was approximately the same.

  In the same manner as in Example 3, the pH and viscosity of the milk protein-containing aqueous solution of each formulation were measured before and after the heat treatment, and the rate of increase in viscosity was calculated. Similarly, the sensory evaluation test was done about the food texture of the milk protein containing aqueous solution (namely, milky drink) after heat processing. The ionic strength was calculated from the concentration of ions in the pH adjuster.

The results were as shown in Table 10.
From the results, it was considered that the effect of increasing the viscosity of the dairy beverage was less related to the ionic strength and the effect of pH would be high.

Example 6: [Effect of milk fat content on viscosity of milk beverage]
The homogenization of the aqueous solution and the heat sterilization treatment were performed in the same manner as in Example 3 except that the compositions 6a to 6d were used according to the following Table 11 as the composition of each milk protein-containing aqueous solution.
The concentration of milk protein in each formulation was the same while the concentration of milk fat was 4.5 wt%, 2.3 wt%, and 0.1 wt%.

  In the same manner as in Example 3, the pH and viscosity of the milk protein-containing aqueous solution of each formulation were measured before and after the heat treatment, and the rate of increase in viscosity was calculated. Similarly, the sensory evaluation test was done about the food texture of the milk protein containing aqueous solution (namely, milky drink) after heat processing.

The results were as shown in Table 12.
It was found that the rate of increase in the viscosity of the dairy beverage was almost unaffected by the concentration of milk fat. In the sample having a large increase rate of the viscosity, the texture was also clearly changed. At this time, in the sample containing a large amount of fat, a rich feeling tends to remain on the tongue, which is a more preferable texture.

Example 7: [Effect of homogenization on viscosity of milk beverage]
The composition of each milk protein-containing aqueous solution was prepared according to the following Table 13 in the same formulation 7a and 7b, and each formulation was subjected to a pressure of 0 kg / cm ² (without homogenization) and 150 kg / cm ² (1st: 100 kg). ^{/ cm 2, 2nd: 50kg /} cm 2), the flow rate 100L / h, except that the homogenization temperature at 60 ° C., in the same manner as in example 3, an experiment was conducted.

  In the same manner as in Example 3, the pH and viscosity of the milk protein-containing aqueous solution of each formulation were measured before and after the heat treatment, and the rate of increase in viscosity was calculated. Similarly, the sensory evaluation test was done about the food texture of the milk protein containing aqueous solution (namely, milky drink) after heat processing.

The results were as shown in Table 14.
It was recognized that the increase rate of the viscosity of the milk beverage was hardly affected by the presence or absence of homogenization treatment (difference in milk fat globule diameter). It was suggested that the homogenization (milk fat globule diameter) may be substantially irrelevant to the rate of increase in the viscosity of the milk beverage.

Example 8: [Effect of pH adjustment on particle size and centrifugal sedimentation rate of milky beverage]
In general, it is known that the particle size and centrifugal sedimentation rate of milk beverages affect the thermal stability (sterilization conditions) of milk beverages. Therefore, for the purpose of confirming physical properties other than the viscosity of the milk beverage, the particle size and centrifugal sedimentation rate of the milk beverage were examined.

  According to Example 4, each milk protein containing aqueous solution of the combination 4a-4e was homogenized and heat-sterilized.

  About each obtained milk drink, the particle size and centrifugal sedimentation rate of the aggregation protein contained therein were measured. The particle size was defined as the volume average particle size when the sample was suspended in a citrate buffer and measured using a laser diffraction particle size distribution analyzer (manufactured by Shimadzu Corporation, SALD-2100). In addition, the centrifugal sedimentation rate is determined by precipitation with respect to the total amount of the sample when the liquid sample is processed at a rotational speed of 2000 rpm for 10 minutes (about 7200 G) using a centrifugal separator (TOMY LC-122, manufactured by Tommy Seiko Co., Ltd.). The percentage of the product.

The results were as shown in Table 15.
There is no correlation between the rate of increase in the viscosity of the milk beverage and the particle size or centrifugal sedimentation rate. Was observed to increase.

Example 9: [Thermal stability of milky drink]
The thermal stability of the dairy beverage was confirmed using a vial bottle shaking type thermal stability tester (oil bath, temperature 140 ° C.). The test was conducted according to the following procedure.
(1) The thermal stability of each milk drink was examined by changing the concentration (pH) of the pH adjuster of the milk drink. Specifically, first, each milk protein-containing aqueous solution of Formulations 9a to 9f was prepared according to Table 16 below, and about 3 ml of each sample of each aqueous solution was filled in a transparent glass small container (vial bottle).
(2) Each vial was immersed in an oil bath (shaking tester) having a temperature of 140 ° C. This tester used an apparatus (Ishiyama Scientific Co., Ltd., vial-vibration-type thermal stability tester) that reciprocates the vial in the left-right direction and shakes it in the oil bath.
(3) The inside of the vial was observed while stopping the shaking operation every predetermined time. At this time, the time when the aggregate was visually confirmed was compared, and the thermal stability was relatively evaluated for each sample.

The results were as shown in Table 16. Here, the value of thermal stability means the time when the agglomerate was confirmed, and the shorter the time when the agglomerate was confirmed, the worse the thermal stability, the longer the time, the better the thermal stability. means.
Even when a pH adjusting agent was added to the milk beverage and its concentration (pH) was changed, there was hardly any adverse effect on the heat stability. The obtained stability was a desirable level in order to make it difficult for the sterilizer to burn or block the channel in the milky beverage production process.

It is a figure which shows the result of Example 3 regarding the influence on the viscosity of the milky drink by addition of a pH adjuster.

Claims (10)

A pH adjustment treatment is performed in advance, comprising at least 3.0 to 8% by weight of food protein, and increasing the pH value of the aqueous medium by 0.1 to 1.2 to bring the pH value to 6.8 to 8. A dairy drink having a novel texture accompanying an increase in viscosity, obtained by heat-treating a pH-adjusted food protein-containing aqueous solution under heat sterilization conditions.   The dairy beverage according to claim 1, wherein the food protein is milk protein. The dairy drink according to claim 1 or 2, wherein the heat treatment is performed by heating at 110 to 150 ° C for 0.1 seconds to 15 seconds. The pH adjusting process, sodium bicarbonate, sodium hydroxide, carried out by adding a pH adjusting agent selected from the group consisting of potassium hydroxide, and sodium carbonate, according to any one of claims 1 to 3 Milky drink. The foodstuff which comprises the dairy drink as described in any one of Claims 1-4 . A pH adjustment treatment is performed in advance, comprising at least 3.0 to 8% by weight of food protein, and increasing the pH value of the aqueous medium by 0.1 to 1.2 to bring the pH value to 6.8 to 8. It has a novel texture associated with an increase in viscosity, comprising obtaining a milky beverage having an increased viscosity by heat-treating a pH-adjusted food protein-containing aqueous solution under heat sterilization conditions. A method for producing a dairy beverage. PH adjustment is obtained by obtaining a food protein-containing aqueous solution comprising at least 3.0 to 12% by weight of food protein and adding a pH adjuster thereto to increase the pH value of the aqueous solution by 0.1 to 1.2. The method according to claim 6 , further comprising obtaining a finished food protein-containing aqueous solution. The method according to claim 6 or 7 , wherein the food protein is milk protein. The method according to any one of claims 6 to 8 , wherein the heat treatment is performed by heating at 110 to 150 ° C for 0.1 seconds to 15 seconds. The pH adjusting process, sodium bicarbonate, sodium hydroxide, carried out by adding a pH adjusting agent selected from the group consisting of potassium hydroxide, and sodium carbonate, according to any one of claims 6-9 Method.

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