JP2007143469A - Emulsion stabilizer and milk beverage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide coffee beverage suppressed in floatation of milk component even if having a large amount of roasted coffee beans or using deeply roasted coffee beans, and free from aggregation even if being preserved for a long period. <P>SOLUTION: An emulsion stabilizer contains (A) polyglyceryl fatty acid ester having an average polymerization degree of 2-5 and containing 50 wt.% of monoester, and (B) polyglyceryl fatty acid ester having an average polymerization degree of 8-20 and a clouding point of ≥80°C, measured in 20 wt.% of sodium chloride aqueous solution at 1 wt.% concentration. Milk beverage containing the emulsion stabilizer is also provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an emulsion stabilizer and a milk beverage.

  In recent years, many coffee beverages that emphasize the original taste of coffee beans reflecting consumer preferences have been produced and sold, but in milk-containing coffee beverages, separation of milk components during storage has been a problem more than before. It has become. That is, in the milk component-containing coffee beverage, the milk component floats on the upper portion with long-time storage. This phenomenon is well known in milk coffee and the like, but the milk components that have floated with the passage of time aggregate and coalesce into a so-called neck ring state. In this case, the redispersibility deteriorates, and the lump of milk components floats on the upper part even after redispersion.

  In recent years, in particular, beverages containing PET bottles have become widespread instead of canned beverages, so emulsification stability of milk components has become more important. This is because the PET bottle is a transparent container, so that the consumer can see the appearance of the coffee. If separation of milk components occurs in the PET bottle beverage, it gives the consumer an unpleasant impression and the commercial value decreases. Or may cause complaints.

  Furthermore, recently, the amount of roasted coffee beans is large, and beverages in PET bottles using beans with various roasting degrees are increasing. However, coffee beverages containing coffee beans extract and milk components that are deeply roasted. Then, it is known that the buoyancy of the milk component is accelerated.

  In order to produce milk coffee that maintains good emulsification stability and flavor even when stored for long periods of time in a vending machine, the constituent fatty acids are mainly HLP10 with a high monoester content and mainly palmitic acid. There is known a method of adding a sucrose fatty acid ester in combination with a sucrose fatty acid ester having a constituent fatty acid of less than HLB 10 mainly composed of stearic acid (Patent Document 1).

  Moreover, in order to maintain long-term emulsification stability in milk beverages in PET bottles, sucrose fatty acid esters of HLB 10 or higher and 20% by weight aqueous sodium chloride solution whose constituent fatty acids are mainly palmitic acid and have a high monoester content A method of adding a combination of polyglycerin fatty acid esters having a cloud point of 90 ° C. or higher measured at a concentration of 1 wt% is known (Patent Document 2).

In addition, in order to suppress germination and growth of heat-resistant spore bacteria when a milk component-containing beverage is sterilized by retort and stored for a long time under high temperature conditions, and further to maintain the emulsion stability of the contents, A method of adding glycerin fatty acid monoester, polyglycerin fatty acid ester of HLB 3-16, sucrose fatty acid ester of HLB 3-16, and the like is known (Patent Document 3).
JP 7-289164 A JP 2000-333599 A JP-A-10-165151

  In the prior art, milk coffee with a large amount of roasted coffee beans and deep roasting has not been sufficiently satisfactory in emulsion stability. Therefore, even when the amount of roasted coffee beans is large or when deeply roasted coffee beans are used, the development of a coffee beverage that suppresses the rise of milk components and does not agglomerate even after long-term storage is desired. Yes.

  Thus, as a result of intensive studies, the present inventors have found that when a specific emulsion stabilizer is blended in a milk beverage, the floatation of milk components is suppressed and the emulsion stability is improved, and the present invention has been achieved. . That is, the first gist of the present invention is a polyglycerin fatty acid ester (A) having an average degree of polymerization of 2 to 5 and a monoester content of 50% by weight or more, and an average polymerization. Polyglycerin fatty acid ester having a degree of 8 to 20 and containing a polyglycerin fatty acid ester (B) having a cloud point of 80 ° C. or higher measured at a concentration of 1% by weight in a 20% by weight aqueous sodium chloride solution. The emulsifying stabilizer is characterized. And the 2nd summary of this invention exists in the milk drink characterized by containing said emulsion stabilizer.

  The milk beverage of the present invention can suppress the floating of milk components after heat sterilization by adding a specific emulsion stabilizer, and also has good emulsion stability after long-term storage.

  Hereinafter, the present invention will be described in detail. The emulsion stabilizer of the present invention is a polyglycerol fatty acid ester having an average degree of polymerization of 2 to 5, and a monoglycerol content of 50% by weight or more, and an average degree of polymerization of 8 A polyglycerin fatty acid ester (B) having a cloud point of 80 ° C. or higher, measured at a concentration of 1% by weight in a 20% by weight sodium chloride aqueous solution.

  The polyglycerin fatty acid ester (A) used in the present invention is a polyglycerin fatty acid ester having an average degree of polymerization of 2 to 5, and examples of the polyglycerin include diglycerin, triglycerin, and tetraglycerin. Of these, diglycerin is preferred. The polyglycerol fatty acid ester (A) has a monoester content of 50% by weight or more, but preferably 70% by weight or more. The carbon number of the constituent fatty acid of the polyglycerol fatty acid ester (A) is usually 8 to 22, preferably 10 to 22, and more preferably 14 to 18. The constituent fatty acid may be either saturated or unsaturated, but is preferably a saturated fatty acid. Specific examples include caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, oleic acid and the like, among which palmitic acid is preferable. Constituent fatty acids may be used in combination of two or more. Those having a monoester content of 70% by weight or more and containing palmitic acid as a main component (preferably 80% by weight or more) are preferable because they have a high effect of suppressing the growth of thermospore bacteria.

  The polyglycerol fatty acid ester (B) used in the present invention is a polyglycerol fatty acid ester having an average polymerization degree of 8 to 20, and a polyglycerol having an average polymerization degree of 8 to 12 is preferable. Specific examples of the fatty acid constituting the polyglycerol fatty acid ester (B) include saturated or unsaturated fatty acids having 14 to 22 carbon atoms such as myristic acid, palmitic acid, stearic acid, behenic acid, and oleic acid. . Among these, fatty acids having 14 to 18 carbon atoms are preferable, and saturated fatty acids are preferable. In particular, those containing myristic acid as the main component are preferred.

  The polyglycerin fatty acid ester (B) has a cloud point of 80 ° C. or higher measured at 1% by weight in a 20% by weight sodium chloride aqueous solution, and a cloud point of 90 ° C. or higher measured under the same conditions. Hydrophilic polyglycerol fatty acid esters are preferred.

The polyglycerol fatty acid ester having the cloud point as described above is usually obtained by reducing the use ratio of the fatty acid to the polyglycerol and reacting at a temperature of 180 to 260 ° C. in the presence of an alkali catalyst. The ratio of fatty acid to polyglycerin fatty acid ester is usually 2 mol times or less. As the alkali metal catalyst, K ₂ CO ₃ , KOH, Na ₂ CO ₃ , NaOH or the like is used, and the use ratio thereof is 5 × 10 ⁻⁷ to 1 mol times with respect to polyglycerol.

A polyglycerin fatty acid ester having a cloud point of 90 ° C. or higher is usually a method in which the amount of alkali catalyst is reduced (5 × 10 ^{−7 to} 0.1 mol times with respect to polyglycerin) and the latter half temperature is increased by a two-stage reaction. For example, after the esterification reaction at a reaction temperature of 180 to 260 ° C., the reaction temperature can be further increased by 10 to 50 ° C. and reacted for 1 to 4 hours (see JP-A-7-145104).

  Various chemical analysis methods have been used so far for the analysis of polyglycerin fatty acid esters (hereinafter sometimes abbreviated as “PoGE”). For example, an acid value, a saponification value, and a hydroxyl value have often been used to grasp the degree of esterification and the amount of residual fatty acid. In addition, evaluation methods such as analysis of ash to know the amount of soap and residual catalyst have been used.

  However, polyglycerin (hereinafter sometimes abbreviated as “PoG”), which is a raw material for PoGE, is a polycondensate of glycerin and is difficult to purify. As well as branched polymers and cyclic polymers. Therefore, PoGE which is an ester form thereof is a composition containing PoGE having various degrees of esterification with different PoG skeletons and unreacted PoG. In addition, PoGE may contain a by-product soap produced by the reaction between the alkali catalyst used in the esterification reaction and the starting fatty acid. Furthermore, when the esterification reaction is insufficient, or when a fatty acid exceeding the stoichiometric amount is used excessively, unreacted fatty acid may be contained.

  Thus, since PoGE is a complex mixture, it is difficult to specify the overall characteristics of PoGE by conventional chemical analysis. For example, even if the average degree of esterification of PoGE is similar or the same, physical properties such as emulsion stability may be significantly different. Conventional chemical analysis such as average degree of esterification, unreacted PoG amount, etc. The physical properties cannot be sufficiently grasped only by the physical property values obtained by the technique, and there is a problem in the physical property evaluation method. Therefore, in recent years, “cloud point” has been adopted in order to define the overall characteristics of the polyglycerol fatty acid ester composition.

  In general, the cloud point is defined as the temperature at which a nonionic surfactant aqueous solution derived from ethylene oxide is separated into two phases due to an increase in temperature and becomes heterogeneous, and is a method for evaluating the physical properties of polyoxyethylene surfactants. (Oil and fat terms dictionary: edited by Japan Oil Chemistry Association (Shoshobo)). The cloud point is sensitive to the structure and composition of the polyglycerin fatty acid ester and reflects the fatty acid soap, so that the degree of hydrophilicity and the difference in composition can be more accurately identified, and can be measured easily. Therefore, the cloud point is the most excellent physical property representative of the characteristics of the polyglycerol fatty acid ester composition. In the polyglycerol fatty acid ester composition, the cloud point is more useful than HLB (balance between hydrophilicity and hydrophobicity). It will be a good indicator.

  Since polyglycerin has a large number of hydroxyl groups, it generally has a higher cloud point than the polyoxyethylene surfactant and may exceed the boiling point of water. In such a case, the measurement can be facilitated by using an appropriate aqueous salt solution (Japanese Patent Laid-Open No. 9-157386). In general, the higher the hydrophilicity, the higher the cloud point, and the higher the monoester content, the higher the cloud point even if the esterification rate is the same.

  The cloud point is usually measured after dissolving the polyglycerol fatty acid ester in 1 to 30% by weight of sodium chloride or sodium sulfate aqueous solution. The conditions at that time vary depending on the solubility of the target sample, but in the case of the present invention, the polyglycerin fatty acid ester is dispersed in a 20 wt% sodium chloride aqueous solution so as to be 1 wt%, and stirred while heating. Make a uniform aqueous solution. The obtained polyglycerol fatty acid ester homogeneous aqueous solution is shaken and allowed to stand at an arbitrary temperature of 0 ° C. or more and 100 ° C. or less in increments of 2 to 5 ° C. so that the polyglycerol fatty acid ester is oily or gel-like. The separated state is measured as a heterogeneous aqueous solution. This non-uniform state is called “cloud point”, and the temperature is obtained in the present invention. The reason for determining the above measurement temperature range is as follows. That is, if it is less than 0 ° C., it is below the melting point of ice, and if it exceeds 100 ° C., it is above the boiling point of water, making accurate cloud point measurement difficult.

  The organic acid monoglyceride (C) used in the emulsion stabilizer of the present invention is a glycerin in which a fatty acid and a polyvalent carboxylic acid are bonded. Specific examples of fatty acids include saturated or unsaturated fatty acids having 8 to 22 carbon atoms such as caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, and oleic acid. When used in beverages, those containing stearic acid as the main component are preferred from the viewpoint of flavor. Examples of the polyvalent carboxylic acid include succinic acid, citric acid, tartaric acid, diacetyltartaric acid, malic acid, adipic acid, glutaric acid, maleic acid, and fumaric acid. Among them, succinic acid that is usually used for foods is used. Acid, citric acid and diacetyltartaric acid can be preferably used, and succinic acid is particularly preferable. In addition, it is not preferable to use a partial salt or a complete salt of a polyvalent carboxylic acid because the ester portion may be decomposed during storage and may not be used for food applications.

  Such organic acid monoglycerides do not have excellent dispersibility in water, but by neutralizing with inorganic salts such as alkali metal salts, fatty acid monoglycerides having a long carbon number can be easily dispersed in water by heating and stirring. It becomes. In this case, the organic acid monoglyceride is not neutralized in advance, and the organic acid monoglyceride and an alkali metal salt such as potassium bicarbonate, potassium carbonate, sodium bicarbonate, sodium carbonate are mixed in a powder state, and this mixture is mixed with water. Mixing is also preferred because it suppresses the decomposition of the organic acid monoglyceride.

  The content ratio of each component in the emulsion stabilizer of the present invention is as follows. That is, the content ratio of the polyglycerin fatty acid ester (A) and the polyglycerin fatty acid ester (B) is preferably (A) / (B) = 0.8-5, particularly 1-2. preferable. The content of the organic monoglyceride (C) is preferably (C) / (B) = 0.01-1 and particularly preferably 0.1-10.

  Examples of the milk beverage used in the present invention include milk coffee and milk tea, and milk coffee is particularly preferable. The coffee beans used in the milk beverage of the present invention are not particularly limited, and two or more kinds of coffee beans may be mixed and used. Usually, roasted coffee beans are used. As a roasting method, an apparatus such as a direct-fire roaster or a hot-air roaster is used, and heating is performed at a temperature of 200 to 300 ° C. until a target L value is reached.

  The L value is an index used to express the degree of roasting of coffee beans. The L value is a value obtained by measuring the lightness of roasted coffee beans with a color difference meter, with black representing L value 0 and white representing L value 100. Accordingly, the deeper the roasted coffee beans, the darker the roasted bean color becomes, so the L value becomes lower and the bitterness of the coffee beverage becomes stronger. Conversely, the shallower the roast, the higher the L value and the stronger the acidity. Usually, coffee beans with a roasting degree of 15 to 35 are used for producing coffee beverages. When the L value is less than 15, the bitterness of the coffee drink becomes too strong, and when the L value exceeds 35, the acidity becomes too strong.

  The coffee extract is obtained as follows. First, using a coffee mill or the like, the roasted coffee beans are pulverized to a predetermined particle size. It is then extracted with hot water. Specifically, the ground coffee beans are usually poured into hot water at 90 to 98 ° C., stirred for about 10 minutes, and then insolubles are removed by filtration.

  In the milk beverage of the present invention, the content of the coffee extract contained in the milk beverage is usually 5 to 10% by weight, preferably 5 to 7% by weight, in terms of green beans. When the content of the coffee extract is less than 5% by weight in terms of green beans, even if the emulsification stabilizer of the present invention is used, the levitation of milk components may be insufficient. Moreover, when content of a coffee extract exceeds 10 weight% in conversion of green beans, the bitterness of coffee is too strong and it is not preferable as milk coffee.

  Examples of the milk component used in the milk beverage of the present invention include milk, whole milk powder, skin milk powder, fresh cream and the like. The milk component may be prepared by separately adding a protein such as skim milk powder and milk fat such as butter or milk oil. Above all, milk is more suitable than powdered milk because it does not impair the smoothness of mouthfeel. The content of the milk component in the milk drink is usually 10 to 60% by weight in terms of milk, but preferably 15 to 30% by weight in the milk drink of the present invention.

  You may add well-known compounding agents, such as another emulsion stabilizer, sugar, a fragrance | flavor, and a vitamin, to the milk beverage of this invention. Examples of other emulsion stabilizers include lecithin, lysolecithin, glycerin fatty acid ester, sucrose fatty acid ester, sorbitan fatty acid ester and the like.

  The milk beverage of the present invention can be prepared as follows. That is, after mixing coffee and tea extract and milk components such as sugar and milk, a preliminarily prepared aqueous solution of an emulsion stabilizer is mixed, and a pH adjuster (such as baking soda) is added to adjust the pH, followed by a homogenizer. Is used for homogenization.

  In preparing the milk beverage, other components added to the milk beverage may be included in the emulsion stabilizer, and the organic acid monoglyceride, polyglycerin fatty acid ester, and diglycerin fatty acid ester having a monoester content of 50% by weight or more. May be individually mixed with other ingredients.

  The content of the emulsion stabilizer in the milk beverage of the present invention is usually 0.05 to 0.3% by weight. Moreover, the density | concentration in the milk beverage of the component which comprises an emulsion stabilizer is as follows. That is, the content of the polyglycerol fatty acid ester (A) is 0.03 to 0.1% by weight, the content of the polyglycerol fatty acid ester (B) is 0.01 to 0.1% by weight, and the organic acid monoglyceride (C) The content of is preferably 0.001 to 0.1% by weight.

  When adjusting the pH, if the amount of sodium bicarbonate added is too large, a heated odor of sodium bicarbonate is produced, and the original scent of coffee changes. Therefore, the pH of milk coffee is usually 5.0 to 7.0, preferably 6.0 to 6.7.

  The milk beverage prepared as described above is subjected to heat sterilization. The sterilization method may be either retort sterilization or UHT sterilization, but UHT sterilization is preferred. The UHT sterilization used in the present invention is an ultra-high temperature sterilization at a sterilization temperature of 130 to 150 ° C. and a sterilization value (Fo) at 121 ° C. corresponding to 10 to 50. UHT sterilization is a direct injection method such as a steam injection method in which steam is directly blown into the beverage, a steam infusion method in which the beverage is injected into steam, and an indirect heating method using a surface heat exchanger such as a plate or tube. It can be performed by a known method. A preferred device is a plate sterilizer.

  EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to a following example, unless the summary is exceeded. The evaluation methods used in the following examples are as follows.

(1) Median particle size (μm)
Milk coffee is stored at 40 ° C. for 4 weeks, and the median particle size (particle size at which the total frequency of appearance of the particle size is 50%) is measured by “LA-920” manufactured by HORIBA.

(2) Oil-off Milk coffee was stored at 40 ° C. for 4 weeks, and the oil-off in which oil droplets were generated on the liquid surface due to emulsion breakage was evaluated according to the following criteria.
○: Oil-off is not observed.
Δ: Slight oil-off is observed.
X: Obvious oil-off is observed.
XX: Oil aggregation (grains) is observed.

(3) Cream-off amount Milk coffee was stored at 40 ° C. for 4 weeks, and the thickness of the milk ring formed on the liquid surface was measured and evaluated according to the following criteria.
A: Less than 2 mm.
○: 2 mm or more and less than 3 mm.
Δ: 3 mm or more and less than 4 mm.
X: 4 mm or more.

(4) Bacteriostatic test 2 ml of milk coffee was dispensed into a TDT tube, and after inoculating 10 ³ cfu / ml of Moorella thermoacetica, which is a heat-resistant spore fungus, the tube was sealed. Five TDT tubes were prepared for each test group, and three TDT tubes were prepared for each test group using a non-inoculated group as a blank. These were stored in a 55 ° C. incubator for 6 weeks and examined for deterioration. The presence or absence of deterioration was confirmed by pH reduction and visual observation of the milk coffee liquid after storage.

Examples 1 and 2
As an emulsion stabilizer, an emulsion stabilizer composed of each component described in Table 1 was used, and milk coffee was prepared according to the following formulation. In Table 1, the ratio of each component of the emulsion stabilizer is shown as the concentration (weight ppm) in the milk beverage.

  First, 0.6 kg of roasted coffee beans (Colombia EX) having an L value of 20 was extracted with 7.8 kg of demineralized water at 95 ° C. to obtain a coffee extract. Then, to the coffee extract 5.25 kg, 2.0 kg of milk, 0.5 kg of granulated sugar, 1.0 kg of an emulsion stabilizer aqueous solution prepared as follows, and 1.25 kg of demineralized water are added, and the total amount is 10 kg. did. Sodium bicarbonate was added to this solution to adjust the pH after sterilization to 6.6.

  The above-mentioned emulsion stabilizer aqueous solution was prepared by using each component shown in Table 1 and dissolving each component in an amount calculated to have the concentration shown in Table 1 in 50 ° C. demineralized water.

  Next, using a high-pressure homogenizer and homogenizing at a pressure of 150 kg / 50 kg at a temperature of 60 to 70 ° C., using a plate type UHT sterilizer (“STS-100” manufactured by Nisaka Seisakusho), a sterilization temperature of 137 ° C. and a sterilization time (Hold time) Sterilized under conditions of 60 seconds (Fo = 40) and filled in a 100 ml heat-resistant glass bottle under aseptic conditions to obtain milk coffee. The evaluation results are shown in Table 2.

Comparative Examples 1-5
In Example 1, it carried out like Example 1 except having used the emulsion stabilizer of Table 1. The evaluation results are shown in Table 2.

Claims (12)

  Polyglycerin fatty acid ester having an average degree of polymerization of 2-5, polyglycerol fatty acid ester (A) having a monoester content of 50% by weight or more, and polyglycerol fatty acid ester having an average degree of polymerization of 8-20 An emulsion stabilizer comprising a polyglycerin fatty acid ester (B) having a cloud point of 80 ° C. or higher measured at a concentration of 1% by weight in a 20% by weight sodium chloride aqueous solution.   The emulsion stabilizer according to claim 1, wherein the content ratio of the polyglycerol fatty acid ester (A) and the polyglycerol fatty acid ester (B) is (A) / (B) = 0.8-5.   Furthermore, the emulsion stabilizer of Claim 1 or 2 containing an organic acid monoglyceride (C).   The emulsion stabilizer according to claim 3, wherein the organic acid monoglyceride (C) is succinic acid monoglyceride.   The emulsion stabilizer according to claim 3 or 4, wherein the content ratio of the organic acid monoglyceride (C) is (C) / (B) = 0.1 to 10.   A milk beverage comprising the emulsion stabilizer according to any one of claims 1 to 5.   The milk beverage according to claim 6, wherein the content of the emulsion stabilizer in the milk beverage is 0.05 to 0.3% by weight.   The content of the polyglycerol fatty acid ester (A) is 0.03 to 0.1% by weight, the content of the polyglycerol fatty acid ester (B) is 0.01 to 0.1% by weight, and the organic acid The milk beverage according to claim 6 or 7, wherein the content of the monoglyceride (C) is 0.001 to 0.1% by weight.   The milk drink according to any one of claims 6 to 8, wherein the milk drink is UHT sterilized.   The milk drink according to any one of claims 6 to 9, wherein the milk drink is milk coffee.   The dairy drink according to claim 10, wherein the coffee extract contained in the dairy drink is extracted from roasted coffee beans having an L value of 15 to 35.   The milk beverage according to claim 10 or 11, wherein the content of the coffee extract contained in the milk beverage is 5 to 10% by weight in terms of green beans.