JP2004267223A - Method for producing milk beverage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing milk beverage sustaining long-term emulsion stability even subjecting to UHT sterilization. <P>SOLUTION: This method for producing the milk beverage comprises passing through an ultra-high temperature (UHT) sterilization treatment. Polyglyceryl fatty acid ester which has ≥90°C clouding point measured in 20% sodium chloride aqueous solution at 1 wt.% concentration is contained in the milk beverage. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a method for producing a milk beverage, and more specifically, to obtain a milk beverage having excellent heat stability and long-term storage stability of an emulsion when subjected to UHT sterilization used for a PET bottled beverage. And a method for producing a milk beverage.

Milk drinks containing milk components such as milk coffee are manufactured through heat sterilization for preservation, but sucrose fatty acid esters are used to prevent deterioration due to the growth of heat-resistant, high-temperature spores that survive. Is widely used. In addition, a method has been proposed in which a polyglycerin fatty acid ester and a sucrose fatty acid ester are used in combination in order to suppress the release of fat and the aggregation of proteins during storage and maintain the emulsion stability for a long period of time (Patent Document 1). These methods are extremely excellent in terms of stability.
JP-A-61-242567. JP-A-62-215345.

  However, these methods have no problem in retort sterilization, but in recent years, when UHT sterilization used for sterilization of PET beverages is performed, the milk protein contained is easily denatured by heat and easily precipitates. The effect is insufficient because the stability is reduced. For this reason, a method of minimizing the treatment time of UHT sterilization and adding a thickening polysaccharide such as pectin and carrageenan has been performed, but it is not sufficient for long-term storage stability.

  Thus, the present inventors have found that a milk beverage containing a polyglycerol fatty acid ester having a specific cloud point can maintain long-term emulsion stability even after being subjected to UHT sterilization, and reached the present invention. did. That is, the gist of the present invention is that when a milk beverage is manufactured through ultra-high temperature (UHT) sterilization, the cloud point measured at a 1% by weight concentration in a 20% aqueous sodium chloride solution in the milk beverage is 90 ° C. or higher. The present invention relates to a method for producing a dairy beverage, comprising a polyglycerin fatty acid ester.

  According to the present invention, there is provided a method for producing a milk beverage which contains milk fat and milk protein and which can maintain long-term emulsion stability even when subjected to UHT sterilization.

  The milk beverage according to the present invention is a beverage containing milk fat and milk protein as milk components, and specific examples include full fat milk powder, milk coffee, milk tea and the like. Examples of the milk component include milk, whole-fat milk powder, skin milk powder, fresh cream, and the like. Proteins such as skim milk powder and milk fat such as butter and milk oil may be separately added and adjusted. The content of the milk component is 5 to 60% by weight, preferably 10 to 25% by weight in terms of milk. Generally, the pH of the milk drink is preferably 5.5 to 7.0, which is neutral or weakly acidic. Of course, other known ingredients such as sugar, fragrance and vitamin may be added.

  The polyglycerin fatty acid ester contained in the milk beverage in the present invention is a mixture of an ester and an unreacted polyglycerin obtained by a reaction between polyglycerin and a fatty acid. It is determined by the type, the esterification ratio of fatty acids (the amount of unreacted polyglycerin), the breakdown ratio of esterification (the ratio of mono-, di-, and tri-forms), but it is extremely difficult to specify all of these requirements. In addition, since this property generally defines the property of the surfactant, it cannot be defined only by the HLB used. Therefore, in the present invention, identification is performed at a “cloud point” which has been recently proposed as a new regulation method.

  The "cloud point" is a phenomenon in which a hydrated nonionic surfactant is dehydrated at a high temperature and separated from water, and is well known among polyoxyethylene-based surfactants. The cloud point is sensitive to the structure and composition of the polyglycerin fatty acid ester and reflects the effect of the fatty acid soap, so that the difference in the degree of hydrophilicity and the composition can be identified more accurately. Furthermore, since it can be easily measured, it is the most excellent physical property representative of the characteristics of polyglycerin fatty acid ester. Therefore, in polyglycerin fatty acid esters, the cloud point is a more useful index than HLB (balance between hydrophilicity and hydrophobicity). Since polyglycerin has a large number of hydroxyl groups, compared to polyoxyethylene-based surfactants, it generally has a higher cloud point and often exceeds the boiling point of water, so in such cases, use an appropriate salt aqueous solution Thus, the measurement can be easily performed (see Japanese Patent Application Laid-Open No. 9-157386). Usually, the stronger the hydrophilicity, the higher the cloud point. Further, even if the esterification rate is the same, an ester composition having a higher monoester content has higher hydrophilicity and a higher cloud point.

  As a cloud point measurement method, it is usually necessary to measure the polyglycerol fatty acid ester after dissolving it in a 1 to 30% sodium chloride or sodium sulfate solution, and the conditions vary depending on the solubility of the target sample. The measuring method in the case of the present invention will be described. In the case of the present invention, first, a polyglycerin fatty acid ester is dispersed in a 20% by weight aqueous sodium chloride solution so as to be 1% by weight, and stirred while heating to obtain a uniform aqueous solution. The obtained homogeneous aqueous solution of polyglycerin fatty acid ester is shaken, stirred and allowed to stand at an arbitrary temperature of 0 ° C. or more and 100 ° C. or less in steps of 2 ° C. to separate the polyglycerin fatty acid ester into an oil or a gel. The temperature in the state of a non-uniform aqueous solution is measured as the “cloud point”. If the temperature is lower than 0 ° C., the temperature is lower than the melting point of ice, and if it is higher than 100 ° C., the temperature is higher than the boiling point of water.

  The cloud point range of the polyglycerol fatty acid ester used in the present invention is 90 ° C. or higher. If the cloud point is lower than this temperature, the effect becomes insufficient. Conventionally, as a high cloud point, for example, decaglycerin monostearate (MSW-750, manufactured by Sakamoto Yakuhin Kogyo Co., Ltd.) is marketed as a hydrophilic brand, and the cloud point is about 82 ° C. Therefore, if this is blended in a milk drink, oil-off due to long-term storage at high temperature cannot be completely suppressed, and a sufficient function as an emulsifier targeted in the present invention cannot be exhibited. However, when the cloud point of the present invention of 90 ° C. or higher is used, good emulsion stability can be maintained for a long time even after UHT sterilization.

  Polyglycerin fatty acid ester is generally obtained by reacting polyglycerin and a fatty acid at a temperature of 180 to 260 ° C. in the presence of an alkali catalyst. There are various brands having different HLB values depending on the reaction charge ratio of glycerin and fatty acid. If the ratio of the charged fatty acid to polyglycerin is large, a brand having low hydrophilicity (low cloud point) is obtained, and if the reverse is true, a brand having high hydrophilicity (high cloud point) is obtained. Therefore, in order to obtain a brand with high hydrophilicity, it is necessary to make polyglycerin equimolar or excess with respect to the fatty acid. However, even with such a charging ratio, it is difficult to obtain a polyglycerol fatty acid ester having a large amount of a monoester compound in a reaction with a normal alkali catalyst, and a high degree of substitution of unreacted polyglycerin and a diester compound or more is obtained. Is obtained containing a relatively large amount of polyglycerin fatty acid ester.

  In order to obtain the polyglycerol fatty acid ester having a specific cloud point of the present invention, a method of reducing the amount of an alkali catalyst and raising the latter half temperature in a two-stage reaction is usually used, for example, an esterification reaction at a reaction temperature of 180 to 260 ° C. Thereafter, a method in which the reaction temperature is further raised by 10 to 50 ° C. and the reaction is carried out for 1 to 4 hours can be used (see JP-A-7-145104). Therefore, in order to obtain a polyglycerol fatty acid ester having a specific cloud point, it is desirable to produce under such specific reaction conditions. For example, even with the known production method described in Patent Document 2, the cloud point of the obtained polyglycerin fatty acid ester is completely different even if the hydroxyl value is the same.

  If the amount of polyglycerin to be reacted is excessive, the product will contain a large amount of unreacted polyglycerin. As the amount of unreacted polyglycerin increases, the hydrophilicity of the polyglycerol fatty acid ester increases, but the actual amount of polyglycerin fatty acid ester decreases, so that the function as an emulsifier is inferior. Therefore, the amount of polyglycerin remaining in the polyglycerin fatty acid ester is preferably 70% by weight or less, more preferably 60% by weight or less.

  Specific examples of the fatty acid constituting the polyglycerin fatty acid ester include a saturated or unsaturated fatty acid having 14 to 22 carbon atoms such as myristic acid, palmitic acid, stearic acid, behenic acid, and oleic acid. A smaller one is preferred. Among them, myristic acid, palmitic acid and stearic acid are preferable, and myristic acid is particularly preferable. The degree of polymerization of the polyglycerol constituting the polyglycerin fatty acid ester is 4-20, preferably 4-12. The content of the polyglycerin fatty acid ester is generally 0.01 to 0.1% by weight, preferably 0.025 to 0.1% by weight in the milk beverage.

  The milk beverage of the present invention may contain various components in addition to the above-mentioned polyglycerin fatty acid ester. In the present invention, the use of sucrose fatty acid ester in particular further improves the stability of the milk beverage itself. Is preferred. The sucrose fatty acid ester usually has a monoester content of 50% or more, and 70% or more of the constituent fatty acids is palmitic acid or stearic acid, particularly, a monoester content of 70% or more. Sucrose fatty acid esters in which at least 80% is palmitic acid are preferred. Mixing of these sucrose fatty acid esters is also preferable from the viewpoint of the bactericidal effect. The content of the sucrose fatty acid ester is preferably, for example, 0.03 to 0.1% by weight, and the ratio of the polyglycerin fatty acid ester to the sucrose fatty acid ester is preferably 1/1 to 7/3 by weight. Other emulsifier components include lecithin, lysolecithin, monoglyceride, organic acid monoglyceride, diglycerin fatty acid ester, sorbitan fatty acid ester and the like.

  According to the method for producing a milk beverage of the present invention, even when sterilization treatment, in particular, UHT sterilization is performed, the heat resistance of the emulsion immediately after sterilization is high, and the emulsion stability can be maintained for a long period of time. Normally, retort sterilization is performed under the conditions of 121 ° C and 20 to 40 minutes, but UHT sterilization used for PET bottle beverages and the like is performed at a higher temperature, for example, at a sterilization temperature of 130 to 150 ° C and at 121 ° C. It is an ultra-high temperature sterilization having a sterilization value (Fo) of 10 to 50. UHT sterilization is a known method such as a direct heating method such as a steam injection method in which steam is directly blown into a beverage or a steam infusion method in which a beverage is injected into steam and heated, and an indirect heating method using a surface heat exchanger such as a plate or a tube. For example, a plate-type sterilizer can be used.

  Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples as long as the gist of the present invention is not exceeded. Further, all ratios, percentages and parts represent weight ratios, weight percentages and parts by weight.

Examples 1 to 3 and Comparative Example 1
40 g of roasted coffee beans were extracted with 400 g of demineralized water at 95 ° C. to obtain a coffee extract. 313 g of coffee extract, 375 g of milk, 84 g of granulated sugar, and 0.1% of the emulsifier shown in Table 1 were blended with respect to the total amount, and desalted water was added thereto to make the total amount to 1500 g. The pH was adjusted to 6.8 by adding baking soda, and the mixture was homogenized using a high-pressure homogenizer at a temperature of 60 to 70 ° C. at a pressure of 150 kg / 50 kg. (Holding time) It was sterilized under the condition of 60 seconds, collected in a 30 g test tube in an aseptic state, and cooled to obtain milk coffee. Next, the obtained milk coffee was stored at 40 ° C. for 2 weeks, and the amount of cream-off was measured using Turbiscan MA2000 manufactured by FormalAction. Table 1 shows the evaluation results.

<Measurement of cream-off amount by Turbiscan MA2000>
By scanning the light source up and down the sample tube at regular time intervals, the backscattered light from the sample is detected, and the change rate of the backscattered light intensity with respect to the measurement time is observed. I can figure it out. Measurement of the upper part of the sample tube provides information on the amount of cream off. As the rate of change of the backscattered light intensity increases with time, the cream-off amount increases and the emulsion stability deteriorates. Then, the emulsion stability (creaming) in Table 1 was evaluated as follows.
：: Change rate of backscattered light intensity at 400 minutes is less than 3% ○: Change rate of backscattered light intensity at 400 minutes is less than 3% to less than 4% Δ: Change rate of backscattered light intensity at 400 minutes Is 4% or more

Example 4 and Comparative Examples 2-3
49.5 g of whole fat milk powder, 90 g of granulated sugar and decaglycerin stearate having a cloud point shown in Table 2 as an emulsifier were blended so as to be 0.05% based on the total amount, and this was dissolved in deionized water. The pH was adjusted to 6.6 with a 1N aqueous lactic acid solution to make the total amount 1500 g. This was homogenized using a high-pressure homogenizer at a temperature of 60 to 70 ° C. at a pressure of 150 kg / 50 kg, and then sterilized by a plate-type UHT sterilizer under the conditions of a sterilization temperature of 132 ° C. and a sterilization time (hold time) of 90 seconds. In this state, 30 g was collected in a test tube and cooled to obtain a whole fat powder emulsion. Immediately after sterilization and after storage at 55 ° C. for 2 months, the median particle size (particle size at which the total frequency of particle size is 50%) is measured and visually observed to evaluate the emulsion stability. did. The particle size was measured using LA-500 manufactured by HORIBA. The evaluation results are summarized in Table 2.

The oil-off state in Table 2 was evaluated as follows.
<Oil-off evaluation criteria>
：: No oil-off is observed at all △: Very slight oil-off is observed ×: Aggregates generated by oil-off are observed

Production Example 1
188 g (0.27 mol) of decaglycerin (average degree of polymerization 9.15, average molecular weight 695, hydroxyl value 900) and 62 g (0.27 mol) of myristic acid (purity 99%, average molecular weight 228) were stirred with a heating jacket. The reaction vessel was charged, 0.025 g of 25% sodium hydroxide (0.0025% of the total amount of the raw material) was added, and the temperature was raised to 240 ° C. in a nitrogen stream, followed by a reaction for 3 hours, and further at 260 ° C. for 4 hours. The reaction was performed to obtain 234 g of decaglycerin myristate.

Production Example 2
Production Example 1 using 183 g (0.26 mol) of decaglycerin (average degree of polymerization 9.15, average molecular weight 695, hydroxyl value 900) and 67 g (0.25 mol) of palmitic acid (purity 96%, average molecular weight 257). The reaction was carried out in the same manner as described above to obtain 229 g of decaglycerin palmitic acid ester.

Examples 5 to 8 and Comparative Example 4
100 g of black tea leaves (Timbra tea) were extracted with 1000 g of demineralized water at 80 ° C. to obtain a black tea extract. Subsequently, 250 g of black tea extract, 500 g of milk, and 150 g of sugar were mixed, and subsequently, 500 g of an emulsifier aqueous solution obtained by dissolving 2.5 g of the emulsifier shown in Table 3 in 497.5 g of demineralized water was added. 2500 g. This was homogenized using a high-pressure homogenizer at a temperature of 60 to 70 ° C. at a pressure of 150 kg / 50 kg cm ⁻² , and then sterilized by a plate-type UHT sterilizer at a sterilizing temperature of 137 ° C. and a sterilizing time (hold time) of 60 seconds. Then, it was filled into a sterilized 500 mL PET bottle and cooled to obtain milk black tea. For the black tea immediately after sterilization and after storage at 40 ° C. for 2 months, the median particle size (particle size at which the total appearance frequency of the particle size becomes 50%) was measured. The cream-off amount of milk tea after storage at 40 ° C. for 2 months was measured by TurbiScan MA2000 manufactured by FormalAction. Further, the redispersibility of the cream and the oil-off after storage at 40 ° C. for 2 weeks and after storage for 2 months were evaluated by visual observation of the PET bottle. Table 3 summarizes the evaluation results.

The cream-off amount, cream redispersibility, and oil-off in Table 3 were evaluated as follows.
<Cream off amount evaluation criteria>
：: Change rate of backscattered light intensity at 600 minutes is less than 3% ：: Change rate of backscattered light intensity at 600 minutes is 3% to less than 4% Δ: Change rate of backscattered light intensity at 600 minutes : Less than 4% to 5% ×; change rate of backscattered light intensity at 600 minutes is 5% or more <Cream redispersibility evaluation criteria>
◎: Dispersed only by slightly shaking ○: Dispersed when shaked for a while △: Cream adhered to the wall surface and hardly dispersed ×: Cream lump floating <Oil-off evaluation criteria>
：: No oil-off is observed Δ: A small amount of oil-off is observed X: A large amount of oil-off is observed XX: Aggregates generated by oil-off are observed

Claims (5)

In producing a milk beverage through an ultra-high temperature (UHT) sterilization treatment, the milk beverage contains a polyglycerin fatty acid ester having a cloud point of 90 ° C. or more measured at a concentration of 1% by weight in a 20% aqueous sodium chloride solution. A method for producing a milk beverage, comprising: The method for producing a milk beverage according to claim 1, wherein the content of the polyglycerin fatty acid ester in the milk beverage is 0.01 to 0.1% by weight. The method for producing a milk beverage according to claim 1 or 2, wherein the milk beverage further contains a sucrose fatty acid ester. The method for producing a milk beverage according to claim 3, wherein the content of the sucrose fatty acid ester in the milk beverage is 0.03 to 0.1% by weight. The method for producing a milk beverage according to any one of claims 1 to 4, wherein the milk beverage is a whole fat milk powder, milk coffee, or milk tea.