JP3830948B2 - Milk beverage production method - Google Patents

Description

  The present invention relates to a method for producing a milk beverage, and more particularly, to obtain a milk beverage excellent in thermal stability of emulsion and long-term storage stability when subjected to UHT sterilization used for PET bottled beverages. The present invention relates to a method for producing a milk beverage.

Milk beverages containing milk components such as milk coffee are manufactured through heat sterilization treatment for storage, but sucrose fatty acid esters are used to prevent deterioration due to the growth of heat-resistant thermophilic spore bacteria. It is widely performed to add. In addition, a method of using a polyglycerin fatty acid ester and a sucrose fatty acid ester in combination has been proposed in order to suppress the release of fat and protein aggregation during storage and to maintain the emulsion stability for a long period of time (Patent Document 1). , Patent Document 2, etc.), these methods are very excellent in terms of stability.
Japanese Patent Laid-Open No. 61-242567. JP-A-62-215345.

  However, these methods have no problem with retort sterilization, but in recent years, when UHT sterilization, which has been used for sterilization of PET beverages, is performed, the milk protein contained tends to precipitate due to heat denaturation and storage. Since the stability is lowered, the effect is insufficient. For this reason, a method of minimizing the processing time of UHT sterilization and adding thickening polysaccharides such as pectin and carrageenan has been performed, but it is not sufficient for long-term storage stabilization.

Thus, the present inventors have found that a milk beverage containing a polyglycerin fatty acid ester having a specific cloud point can retain long-term emulsification stability even after being subjected to UHT sterilization. did. That is, the gist of the present invention is to produce a milk beverage through ultra-high temperature (UHT) sterilization treatment, and the cloud point measured at a concentration of 1% by weight in a 20% sodium chloride aqueous solution is 95 ° C. or higher It exists in the manufacturing method of the milk drink characterized by including polyglyceryl fatty acid ester.

  ADVANTAGE OF THE INVENTION By this invention, the manufacturing method of the milk beverage which contains milk fat content and milk protein, and can maintain long-term emulsion stability even if it performs UHT sterilization is provided.

  The milk beverage in the present invention is a beverage containing milk fat and milk protein, which are milk components, and specific examples thereof include full fat milk powder, milk coffee, milk tea and the like. Examples of the milk component include cow's milk, whole milk powder, skin milk powder, fresh cream, and the like. Proteins such as skimmed milk powder and milk fats such as butter and milk oil may be individually 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. The pH of the milk drink is usually preferably neutral or weakly acidic from 5.5 to 7.0. Of course, other known compounding agents 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 obtained by reaction of polyglycerin and a fatty acid and unreacted polyglycerin, and the characteristics of this mixture are the polymerization degree of polyglycerin, the fatty acid Although it is determined by the type, esterification rate of fatty acid (amount of unreacted polyglycerin), breakdown ratio of esterification (ratio of mono-, di-, tri-, etc.), it is extremely difficult to specify all these requirements. Moreover, since this characteristic generally defines the characteristic of a surfactant, it cannot be defined only by the HLB used. Therefore, in the present invention, the “cloud point”, which has been recently proposed as a new regulation method, is specified.

  “Cloud point” is a phenomenon in which a hydrated nonionic surfactant is dehydrated at high temperature and separated from water, and is well known for polyoxyethylene surfactants. The cloud point is sensitive to the structure and composition of the polyglycerol fatty acid ester and reflects the influence of the fatty acid soap, so that the degree of hydrophilicity and the difference in composition can be more accurately identified. Furthermore, since it can measure simply, it is the most excellent as a physical property which represents the characteristic of polyglycerol fatty acid ester. Therefore, in the polyglycerol fatty acid ester, the cloud point is a more useful index than HLB (balance between hydrophilicity and hydrophobicity). Since polyglycerin has a large number of hydroxyl groups, it generally has a higher cloud point than polyoxyethylene surfactants, and many of them exceed the boiling point of water. In such cases, use an appropriate aqueous salt solution. Therefore, the measurement can be easily performed (see Japanese Patent Laid-Open No. 9-157386). Usually, the stronger the hydrophilicity, the higher the cloud point. 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 after dissolving a polyglycerol fatty acid ester in 1 to 30% sodium chloride or sodium sulfate solution, and the conditions differ depending on the solubility of the target sample, A measurement method in the case of the present invention will be described. In the case of the present invention, first, the polyglycerol fatty acid ester is dispersed in a 20% by weight sodium chloride aqueous solution so as to be 1% by weight, and stirred while heating to obtain a uniform aqueous solution. The resulting polyglycerol fatty acid ester homogeneous aqueous solution is shaken and allowed to stand in increments of 2 to 5 ° C. at an arbitrary temperature of 0 ° C. or more and 100 ° C. or less, so that the polyglycerol fatty acid ester is separated like an oil or gel. Then, the temperature in a state where the aqueous solution is inhomogeneous is measured as “cloud point”. If it is less than 0 ° C., it is less than the melting point of ice, and if it exceeds 100 ° C., it becomes more than the boiling point of water.

When the cloud point of the polyglycerol fatty acid ester used in the present invention is lower than 90 ° C. , the effect becomes insufficient. Conventionally, for example, decaglycerin monostearate (MSW-750 manufactured by Sakamoto Yakuhin Kogyo Co., Ltd.) is commercially available as a hydrophilic brand as a high cloud point, and this cloud point is about 82 ° C. Therefore, if this is blended into a milk beverage, oil-off due to high-temperature long-term storage cannot be completely suppressed, and a sufficient function as an emulsifier targeted in the present invention cannot be exhibited. However , when a cloud point of 90 ° C. or higher is used, good emulsification stability can be maintained for a long time even after UHT sterilization. In the present invention, those having a cloud point of 95 ° C. or more are used.

  Polyglycerin fatty acid esters are generally obtained by reacting polyglycerin and fatty acids in the presence of an alkali catalyst at a temperature of 180 to 260 ° C. Polyglycerin fatty acid esters distributed in the market include polyglycerin fatty acid esters. There are various brands with different HLB values depending on the reaction charge ratio of glycerin and fatty acid. A brand with low hydrophilicity (low cloud point) is obtained when the ratio of fatty acid to polyglycerin is large, and a brand with high hydrophilicity (high cloud point) is obtained in the opposite case. Therefore, when trying to obtain a brand having high hydrophilicity, it is necessary to make polyglycerin equimolar or excessive 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 monoesters by a reaction with a normal alkali catalyst, and the degree of substitution higher than that of unreacted polyglycerol and diesters is high. Thus, a product containing a relatively large amount of the polyglycerol fatty acid ester can be obtained.

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

  When the polyglycerin to be reacted is excessive, the product contains a large amount of unreacted polyglycerin. The greater the amount of unreacted polyglycerol, the higher the hydrophilicity of the polyglycerol fatty acid ester. However, since the actual amount of polyglycerol fatty acid ester decreases, the function as an emulsifier is inferior. Therefore, the amount of polyglycerol remaining in the polyglycerol 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 saturated or unsaturated fatty acids having 14 to 22 carbon atoms such as myristic acid, palmitic acid, stearic acid, behenic acid, oleic acid, etc. Smaller is preferable. Of these, myristic acid, palmitic acid, and stearic acid are preferable, and myristic acid is particularly preferable. As a polymerization degree of the polyglycerol which comprises polyglycerol fatty acid ester, an average polymerization degree is 4-20, Preferably an average polymerization degree is 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 in the present invention can contain various components in addition to the above-mentioned polyglycerin fatty acid ester, but in the present invention, particularly when sucrose fatty acid ester is used in combination, the stability of the milk beverage itself is further improved. This is preferable. As the sucrose fatty acid ester, the monoester content is usually 50% or more, 70% or more of the constituent fatty acid is palmitic acid or stearic acid, in particular, the monoester content is 70% or more, Sucrose fatty acid esters in which 80% or more is palmitic acid are preferred. The blending of these sucrose fatty acid esters is also preferable from the viewpoint of bactericidal effect. The content of sucrose fatty acid ester is, for example, preferably 0.03 to 0.1% by weight, and the ratio of polyglycerin fatty acid ester to sucrose fatty acid ester is preferably 1/1 to 7/3 by weight. Examples of other emulsifier components include lecithin, lysolecithin, monoglyceride, organic acid monoglyceride, diglycerin fatty acid ester, sorbitan fatty acid ester, and the like.

  The milk beverage production method of the present invention has high heat resistance of the emulsion immediately after sterilization and can maintain long-term emulsification stability even after sterilization treatment, particularly UHT sterilization. Usually, retort sterilization is performed under the conditions of 121 ° C. and 20 to 40 minutes, but UHT sterilization used for beverages for PET bottles and the like has a higher temperature, for example, a sterilization temperature of 130 to 150 ° C. and 121 ° C. The sterilization value (Fo) is ultrahigh temperature sterilization corresponding to 10-50. UHT sterilization is a known method such as a direct injection method such as a steam injection method in which water vapor is directly blown into a beverage or a steam infusion method in which a beverage is injected into the water vapor and an indirect heating method using a surface heat exchanger such as a plate or tube. For example, a plate type sterilizer can be used.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited to a following example, unless the summary is exceeded. Further, the ratio,% and part all represent the weight ratio, weight% and part by weight.

Examples 1 to 3 and Comparative Example 1
40 g of roasted coffee beans were extracted with 400 g of 95 ° C. demineralized water to obtain a coffee extract. 313 g of coffee extract, 375 g of milk, 84 g of granulated sugar and the emulsifier described in Table 1 were blended in 0.1% with respect to the total amount, and demineralized water was added thereto to make the total amount 1500 g. Sodium bicarbonate was added to adjust the pH to 6.8, and this was homogenized at a pressure of 150 kg / 50 kg at a temperature of 60-70 ° C. using a high-pressure homogenizer, and then sterilized at a temperature of 137 ° C. using a plate type UHT sterilizer. (Hold time) Sterilized under conditions of 60 seconds, collected in a 30 g test tube under aseptic conditions, 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 with a Turboscan MA2000 manufactured by Formaaction. The evaluation results are shown in Table 1.

<Measurement of cream-off amount by Turbscan MA2000>
By scanning the light source in the vertical direction of the sample tube at regular time intervals, the backscattered light from the sample is detected, and the rate of change in the backscattered light intensity with respect to the measurement time is observed, so that the cream-off state is detected. I can grasp it. By measuring the upper part of the sample tube, information on the amount of cream-off is obtained. As the rate of change of the backscattered light intensity increases with time, the amount of cream-off increases and the emulsification stability is inferior. Therefore, the emulsion stability (creaming) in Table 1 was evaluated as follows.
A: 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 4% or more

Example 4 and Comparative Examples 2-3
49.5 g of whole milk powder, 90 g of granulated sugar and decaglycerin stearic acid ester having the cloud point shown in Table 2 as an emulsifier were mixed so as to be 0.05% based on the total amount, and this was dissolved in demineralized water, The pH was adjusted to 6.6 with a 1 N aqueous lactic acid solution to make the total amount 1500 g. This is homogenized at a temperature of 60-70 ° C. at a pressure of 150 kg / 50 kg using a high-pressure homogenizer, and then sterilized by a plate type UHT sterilizer at a sterilization temperature of 132 ° C. and a sterilization time (hold time) of 90 seconds. In the state, it was collected in a 30 g test tube and cooled to obtain a full fat milk powder. Immediately after sterilization and after storage for 2 months at 55 ° C., the median particle size (particle size at which the total frequency of appearance of particle size is 50%) is measured and visually observed to evaluate the emulsion stability. did. In addition, the particle size measurement used the HORIBA company make and LA-500. 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 Δ: 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 myristic acid (purity 99%, average molecular weight 228) 62 g (0.27 mol) with a heating jacket The reaction vessel was charged with 0.025 g of 25% sodium hydroxide (a total of 0.0025% of raw materials), heated to 240 ° C. under a nitrogen stream, reacted for 3 hours, and further at 260 ° C. for 4 hours. The reaction was performed to obtain 234 g of decaglycerin myristic acid ester.

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) In the same manner as above, 229 g of decaglycerin palmitate was obtained.

Examples 5 to 8 and Comparative Example 4
100 g of black tea leaf (Timbura tea) was extracted with 1000 g of demineralized water at 80 ° C. to obtain a black tea extract. Next, 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 in which 2.5 g of the emulsifier described in Table 3 was dissolved in 497.5 g of demineralized water was added. It was 2500 g. This is homogenized using a high-pressure homogenizer at a temperature of 60 to 70 ° C. and a pressure of 150 kg / 50 kg cm ⁻² , and then sterilized by a plate type UHT sterilizer at a sterilization temperature of 137 ° C. and a sterilization time (hold time) of 60 seconds. Milk tea was obtained by filling a sterile 500 mL PET bottle in a sterile state and cooling. The milk black tea immediately after sterilization and after being stored at 40 ° C. for 2 months was measured for median particle size (particle size at which the total frequency of appearance of particle size is 50%). Moreover, about the milk tea after preserve | saving for 2 months at 40 degreeC, the cream-off amount measurement by FormaAction company make and TurbiScan MA2000 was performed. Furthermore, the redispersibility of the cream and oil-off after storage for 2 weeks at 40 ° C. and after storage for 2 months were evaluated by visual observation of the PET bottle. The evaluation results are summarized in Table 3.

The cream off amount, cream redispersibility, and oil off in Table 3 were evaluated as follows.
<Criteria for cream-off amount>
◎: Change rate of backscattered light intensity at 600 minutes is less than 3% ○: Change rate of backscattered light intensity at 600 minutes is less than 3% to less than 4% Δ: Change rate of backscattered light intensity at 600 minutes Is less than 4% to less than 5% x; the rate of change in backscattered light intensity at 600 minutes is 5% or more <Cream Redispersibility Evaluation Criteria>
◎: Dispersed by lightly shaking ○: Dispersed when shaken for a while △: Cream adheres to the wall and is difficult to disperse ×: Cream lump floats <Oil-off evaluation criteria>
○: Oil-off is not observed Δ: A small amount of oil-off is observed ×: A large amount of oil-off is observed XX: Aggregates generated by the oil-off are observed

Claims (5)

In producing a milk beverage through ultra-high temperature (UHT) sterilization treatment, a polyglycerin fatty acid ester having a cloud point of 95 ° C. or higher measured at a concentration of 1% by weight in a 20% sodium chloride aqueous solution is contained in the milk beverage. A method for producing a milk drink characterized by the above.   The method for producing a milk beverage according to claim 1, wherein the content of the polyglycerol 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, further comprising a sucrose fatty acid ester in the milk beverage.   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 full fat milk powder, milk coffee or milk tea.