JP2006262816A - Method for producing concentrated milk and concentrated milk - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing concentrated milk enabling control of acidity, and to provide concentrated milk produced by the method. <P>SOLUTION: This method for producing the concentrated milk is based on knowledge that acidity can be indirectly controlled by controlling factors with reference to acidity, found through making it clear, as a result of comparing acidity of concentrated milk with each kind of component, that the factors are solid concentration, nonfat milk solid concentration (SNF), refraction sugar content (Brix), and specific gravity (density) or the like in concentration treatment of raw material milk. As a result of this, it is possible to stably produce quality-governing milk having acidity within a standard. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing concentrated milk that enables control of acidity, and a concentrated milk produced by the production method. More specifically, in the process of concentrating raw material milk, a factor relating to acidity is clarified, and by controlling the factor, the acidity is controlled indirectly, and the concentrated milk production method and method It relates to the concentrated milk produced.

  It is said that there are three factors that consumers demand from milk: “naturalness”, “taste”, and “nutrition / function”. Here, the characteristics (advantages and disadvantages) of current milk are summarized as follows. “Normal milk” has a good image of nature and nature, and has a reputation for being delicious, but there is an opinion that it wants more nutrition such as calcium. “Low-fat milk” has a reputation for being low in calories and refreshing, but on the other hand, there is an opinion that it is light in taste and wants more nutrition. “Tokuno Milk” has a reputation for being rich and delicious, but on the other hand, there is an opinion that it has a lot of fat and seems to be fat. “White milk beverages” have been evaluated to be rich in nutrients such as calcium, but on the other hand, there is an opinion that they are artificial and poor in taste. Thus, there has never been a milk that satisfies the three major elements that consumers demand, “naturalness,” “taste,” and “nutrition / function” at the same time. In addition, the value consumers demand for milk has diversified, and new value needs to be provided.

  A new “ingredient-adjusted milk” was born by the amendment of the Ordinance of Milk Ingredient-adjusted milk is obtained by removing specific ingredients (moisture, etc.) from raw milk only (100% raw milk) using techniques such as membrane treatment. (Partial skim milk) ”is excluded. This component-adjusted milk satisfies the three major elements that consumers demand for milk, and may be able to cope with the diversification of values that consumers demand for milk. For example, in the component-adjusted milk obtained by concentrating the non-fat milk solid content, the natural sweetness of the milk is emphasized, and it becomes possible to taste a rich richness and mellowness.

  According to the description on page 42 of the Law Concerning Milk Related Laws (Milk Industry Hygiene Liaison Council, March 2006), the component standard for ingredient-adjusted milk is non-fat milk solid content of 8.0% or more, acidity (as lactic acid) Is 0.18% or less, the number of bacteria (per 1 ml by standard plate culture method) is 50,000 or less, and coliform bacteria are negative. Here, the acidity is a value measured by “5 Method for Measuring Acidity of Milk and Dairy Products” on page 56 of the same book. Thus, in the component-adjusted milk, it is essential to set the acidity according to the standard. However, for example, in order to produce component-adjusted milk, the raw milk is concentrated by membrane separation, and the acidity of the produced concentrated milk is measured. As a result, the acidity exceeds the upper limit value (deviates from the specified value). ), Some were out of specification. Specifically, in the concentration treatment by the membrane separation method, the acidity of concentrated milk with a high concentration concentration and high concentration exceeded the upper limit value, which was out of specification.

  In order to elucidate this phenomenon, the possibility of increasing lactic acid and other organic acids with the change in the component concentration by membrane separation was examined experimentally. Concentrations of lactic acid and citric acid were measured, but lactic acid was hardly detected, and no significant change was found in the concentration of citric acid or the like. As described above, in order to stably produce component-adjusted milk and concentrated milk, it is essential to set the acidity according to the standard, and for that purpose, it is necessary to elucidate the factors that affect the acidity. And it is necessary to control the acidity easily using the factor. The measurement of acidity requires complicated operations such as reagent preparation, titration, and calculation. Therefore, it has been desired to elucidate factors that are easier to measure than acidity, and to use them to easily control the production conditions of component-adjusted milk and concentrated milk, the operating conditions of production equipment, and the like.

  As prior art regarding processed milk in which raw milk is concentrated by membrane separation method and nutritional components such as protein and calcium are increased and a method for producing the same, JP 2002-051699 A (Patent Document 1) and JP 2002-253116 A Gazette (Patent Document 2). These patent documents describe a method of producing processed milk (concentrated milk) by processing raw milk by a reverse osmosis membrane (RO) method or a nanofiltration membrane (NF) method. However, it does not describe the acidity and its control method.

  As prior art relating to fermented milk obtained by concentrating raw material milk by a membrane separation method to increase nutrient components such as protein and calcium, milk powder reduced in sodium and potassium, etc. and a method for producing the same, JP-A 06-014707 ( Patent Document 3) and Japanese Patent Application Laid-Open No. 08-266221 (Patent Document 4). In these patent documents, raw milk is processed by a reverse osmosis membrane (RO) method to produce a concentrated fermented milk, and raw milk is processed by a nanofiltration membrane (NF) method, A method for producing desalted nonfat dry milk is described. However, it does not describe the acidity and its control method.

JP 2002-051699 A JP 2002-253116 A Japanese Patent Laid-Open No. 06-014707 Japanese Unexamined Patent Publication No. 08-266221

  The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide a concentrated milk manufacturing method capable of controlling acidity and a concentrated milk manufactured by the manufacturing method.

  The present invention relates to a method for producing concentrated milk, characterized by controlling acidity indirectly by controlling a factor related to acidity in the concentration treatment of raw milk, and concentrated milk produced by the production method. Another purpose is to provide.

  In view of the above problems, the present inventors have conducted extensive research. As a result, in the concentration treatment of raw milk, factors related to acidity include solid content concentration, non-fat milk solid content concentration (SNF), refractive sugar content ( Brix), specific gravity (density), concentration ratio, etc. were elucidated, and the knowledge that the acidity can be indirectly controlled by controlling the factors was found, and the present invention was completed. .

  As described above, in order to find a factor related to acidity, the possibility of increasing lactic acid, other organic acids, and the like with the change of the component concentration by the membrane separation method was also examined experimentally. Actually, concentrations of lactic acid and citric acid were measured, but almost no lactic acid was detected, and no significant change was found in the concentration of citric acid or the like.

That is, the present invention
[1] Correlation between one or more values of solid content, non-fat milk solid content (SNF), refractive sugar (Brix), specific gravity (density), concentration ratio and acidity in the concentration process of raw milk A method for producing concentrated milk, characterized in that the acidity is controlled using a relationship,
[2] The method for producing concentrated milk according to [1], wherein the correlation is a proportional relationship,
[3] The method for producing concentrated milk according to any one of [1] or [2], wherein the concentration treatment is a membrane separation method,
[4] The method for producing concentrated milk according to [3] above, wherein the membrane separation method is a nanofiltration membrane (NF) method and / or a reverse osmosis membrane (RO) method,
[5] A concentrated milk produced by the production method according to any one of [1] to [4].

  In this specification, “raw milk” is a liquid containing milk components such as raw milk, raw milk, whole milk, skim milk and whey.

  In the present specification, “concentrated milk” is a liquid obtained by concentrating the raw material milk by a membrane separation method, a vacuum evaporation method, or the like. The liquid obtained by adding a sterilization process, a homogenization process, a centrifugation process, a fat concentration adjustment process, etc. may be contained in a post process. In other words, in “concentrated milk”, cream is added to concentrated milk obtained from skim milk, component-adjusted milk with adjusted milk fat concentration, for example, by subjecting concentrated milk obtained from whole milk to a centrifugal separation treatment Thus, component-adjusted milk or the like with adjusted milk fat concentration is also included.

  In this specification, “acidity” is a measurement value according to “5 Measuring Method of Acidity of Milk and Dairy Products” on page 56 of the Laws and Regulations Related to Milk (Milk Industry Hygiene Liaison Council, March 2004). The details are as follows. That is, 10 ml of sample is diluted by adding the same amount of water without carbon dioxide gas, 0.5 ml of phenolphthalein solution is added as an indicator, and a slight red color does not disappear for 30 seconds with 0.1 mol / L sodium hydroxide solution. The amount of lactic acid per 100 g of the sample is determined from the titration amount, and the acidity is obtained. 1 ml of 0.1 mol / L sodium hydroxide solution corresponds to 9 mg of lactic acid. As an indicator, 1 g of phenolphthalein is dissolved in 50% ethanol to make 100 ml.

  In this specification, “proportional relationship” means that the correlation between two factors such as acidity and solid content concentration can be approximated by a linear expression.

  In order to produce component-adjusted milk, the present inventors concentrated raw material milk by a membrane separation method, and measured the acidity of the produced concentrated milk. As a result, the acidity exceeded the upper limit (the specified value was exceeded). There was something that was out of specification. Specifically, in the concentration treatment by the membrane separation method, the acidity of concentrated milk with a high concentration concentration and high concentration exceeded the upper limit value, which was out of specification. In order to elucidate this phenomenon, the effects of concentrations of lactic acid and citric acid were examined, and it was found that there was no effect on their acidity.

  As a result of further experimental investigation and comparison of acidity of concentrated milk with various components, the factors related to acidity in raw milk concentration treatment include solid content, non-fat milk solid content (SNF) ), Refractive sugar (Brix), specific gravity (density), concentration ratio, etc. And the knowledge that an acidity can be controlled indirectly by controlling the factor was found, and it became possible to manufacture stably component-adjusted milk having an acidity within the standard.

  ADVANTAGE OF THE INVENTION According to this invention, the concentrated milk manufactured by the manufacturing method of the concentrated milk which enabled control of acidity, and its manufacturing method can be provided.

  According to the present invention, in the concentration treatment of raw milk, the acidity is controlled indirectly by controlling the factor related to the acidity, and the concentrated milk produced by the production method is characterized by controlling the acidity. Milk can be provided.

  The concentrated milk production method of the present invention is characterized in that, in the concentration treatment of raw milk, the acidity is controlled using the correlation between the acidity and the solid content concentration. The concentration is not limited. Any factor that has a correlation with the solid content concentration can be applied, and non-fat milk solid content concentration (SNF), refractive sugar content (Brix), specific gravity (density), protein concentration, concentration rate, etc. can be exemplified. . Actually, it takes time to measure the solid content, and therefore the method for controlling the acidity in the method for producing concentrated milk of the present invention uses factors that can be easily measured such as the refractive sugar content, specific gravity, and concentration ratio. Is desirable. Incidentally, since the composition of raw milk such as full fat milk and skim milk varies, the correlation between acidity and solid content concentration varies depending on the raw milk and is not constant. Therefore, acidity, solid content concentration, non-fat milk solid content concentration, refractive sugar content, specific gravity, etc. are measured in advance for several types of raw milk, and their correlation is obtained. And it is desirable to control acidity by solid content concentration, non-fat milk solid content concentration, refractive sugar content, specific gravity, etc. on the safe side where the acidity does not deviate from the specified value.

  The concentrated milk production method of the present invention is characterized in that, in the concentration treatment of raw material milk, the acidity is controlled using the correlation between the acidity and the non-fat milk solid content concentration (SNF). As described above, the factor controlling the acidity is not limited to the non-fat milk solid content concentration. Any factor having a correlation with the non-fat milk solid content concentration can be applied, and examples thereof include refractive sugar (Brix), specific gravity (density), and protein concentration.

  The method for producing concentrated milk of the present invention is characterized in that the acidity is controlled using the correlation between acidity and refractive sugar (Brix) in the raw milk concentration process. Refractive sugar can be measured easily and in a short time using a refractometer, so a sample can be taken from the manufacturing process of concentrated milk and the value can be confirmed on the spot. It is possible to indirectly control the acidity within the standard by performing an operation of stabilizing the refractive sugar content at a constant value while intermittently determining whether or not the operation state of the production apparatus is appropriate.

  The method for producing concentrated milk of the present invention is characterized in that the acidity is controlled using the correlation between acidity and specific gravity (density) in the concentration treatment of raw material milk. Since the specific gravity can be measured easily and instantaneously using a hydrometer, a specific gravity meter can be installed in the manufacturing process of concentrated milk to continuously check the numerical value. It is possible to indirectly control the acidity within the standard by performing an operation of stabilizing the specific gravity at a constant value while continuously determining whether or not the operation state of the manufacturing apparatus is appropriate. For example, the specific gravity is automatically controlled by processing the increase or decrease in specific gravity or the tendency of the increase or decrease with a computer or the like, and as a result, the acidity can also be automatically controlled.

  In the method for producing concentrated milk of the present invention, the correlation between acidity and solid content concentration, nonfat milk solid content concentration, refractive sugar content, specific gravity and the like is a proportional relationship. In the present invention, the correlation between two factors can be approximated by a linear expression.

  In the method for producing concentrated milk of the present invention, the concentration treatment is not particularly limited, but it is preferably a membrane separation method because non-heating causes almost no denaturation of nutrient components such as proteins.

  In the method for producing concentrated milk of the present invention, the membrane separation method is not particularly limited, but since there is little loss of nutrient components such as protein and lactose, the nanofiltration membrane (NF) method and / or the reverse osmosis membrane (RO) method It is desirable that The nanofiltration membrane (NF) method and the reverse osmosis membrane (RO) method can be used in combination, and may be installed in series or in parallel. Moreover, according to the composition of the component-adjusted milk to be produced, the mutual membrane area and the ratio thereof may be set freely.

  Hereinafter, although an example is given and explained about the present invention, the present invention is not limited by this.

[Example 1] (Concentration treatment of whole milk by reverse osmosis membrane (RO) method)
Whole fat milk was concentrated by a reverse osmosis membrane (RO) method. The reverse osmosis membrane used is RO-3838 / 30-FF (Dow). Concentrated milk was collected at a predetermined concentration ratio, and acidity, solid content concentration, and non-fat milk solid content concentration were measured. Each correlation is shown in FIGS.

  In this experiment, in FIG. 1, when the acidity is X [%], the solid content concentration is Y [wt%], and the mutual relationship is approximated by a linear expression, Y = 82.55 · X + 3.75. At this time, when the acidity (as lactic acid) of the whole fat milk is set to 0.18% or less as the component standard of the component-adjusted milk, the solid content concentration is set to 18.6% or less. In consideration of controlling the operation of the apparatus on the safe side, when the acidity of the whole milk is set to 0.17% or less, the solid content concentration is set to 17.8% or less. In FIG. 2, when the acidity is X [%], the non-fat milk solid content concentration is Y [wt%], and the mutual relationship is approximated by a linear expression, Y = 56.20 · X + 2.54 is obtained. At this time, when the acidity of the whole milk is set to 0.18% or less, the non-fat milk solid content concentration is set to 12.6% or less. When the acidity of the whole milk is set to 0.17% or less, the non-fat milk solid content concentration is set to 12.1% or less.

[Example 2] (Concentration treatment of skim milk by nanofiltration membrane (NF) method)
The skim milk was concentrated by a nanofiltration membrane (NF) method. The nanofiltration membrane used is NF-3838 / 30-FF (Dow). In the case of skim milk, since the milk fat is hardly contained, the solid content concentration and the non-fat milk solid content concentration are the same. Concentrated milk was collected at a predetermined concentration ratio, and acidity, solid content (non-fat milk solid content), refractive sugar content, and specific gravity were measured. Each correlation is shown in FIGS.

  In this experiment, in FIG. 3, when the acidity is X [%], the solid content concentration is Y [wt%], and the mutual relationship is similar by a linear expression, Y = 65.86 · X + 1.36. At this time, when the acidity of skim milk is set to 0.18% or less, the solid content concentration is set to 13.2% or less. When the acidity of skim milk is set to 0.17% or less, the solid content concentration is set to 12.5% or less. In FIG. 4, when the acidity is X [%], the refractive sugar degree is Y [%], and the mutual relationship is approximated by a linear expression, Y = 71.23 · X + 2.06. At this time, when the acidity of skim milk is set to 0.18% or less, the refractive sugar content is set to 14.9% or less. When the acidity of skim milk is set to 0.17% or less, the refractive sugar content is set to 14.2% or less. In FIG. 5, when the acidity is X [%], the specific gravity is Y [−], and the mutual relationship is approximated by a linear expression, Y = 0.268 · X + 0.999. At this time, when the acidity of skim milk is set to 0.18% or less, the specific gravity is set to 1.047 or less. When the acidity of skim milk is set to 0.17% or less, the specific gravity is set to 1.044 or less.

[Example 3] (Concentration treatment of whey by reverse osmosis membrane (RO) method)
Whey was concentrated by a reverse osmosis membrane (RO) method. The reverse osmosis membrane used is RO-3838 / 30-FF (Dow). In the case of whey, since it contains almost no milk fat, the solid content concentration and the non-fat milk solid content concentration are equivalent. Concentrated milk was collected at a predetermined concentration ratio, and acidity and solid content concentration (non-fat milk solid content concentration) were measured. The respective correlations are shown in FIG.

  In this experiment, in FIG. 6, when the acidity is X [%], the solid content concentration is Y [wt%], and the mutual relationship is similar by a linear expression, Y = 93.88 · X + 2.24.

  It is possible to provide a concentrated milk production method capable of controlling acidity and the concentrated milk produced by the production method. Specifically, in the concentration treatment of raw material milk, the method for producing concentrated milk characterized by controlling the acidity indirectly by controlling the factor related to acidity, and the concentrated milk produced by the production method Can be provided.

FIG. 1 is a graph showing the relationship between acidity and solid content concentration in whole milk. FIG. 2 is a graph showing the relationship between acidity and nonfat milk solid content concentration in whole milk. FIG. 3 is a graph showing the relationship between acidity and solid content concentration in skim milk. FIG. 4 is a graph showing the relationship between acidity and refractive sugar content in skim milk. FIG. 5 is a graph showing the relationship between acidity and specific gravity in skim milk. FIG. 6 is a graph showing the relationship between acidity and solid content concentration in whey.

Claims (5)

  In the concentration process of raw milk, use the correlation between one or more of solid content concentration, non-fat milk solid content concentration (SNF), refractive sugar content (Brix), specific gravity (density), concentration ratio and acidity And the manufacturing method of concentrated milk characterized by controlling acidity.   The method for producing concentrated milk according to claim 1, wherein the correlation is a proportional relationship.   The method for producing concentrated milk according to any one of claims 1 and 2, wherein the concentration treatment is a membrane separation method.   The method for producing concentrated milk according to claim 3, wherein the membrane separation method is a nanofiltration membrane (NF) method and / or a reverse osmosis membrane (RO) method. The concentrated milk manufactured by the manufacturing method of any one of Claims 1-4.

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