JP2005218400A - Milk beverage excellent in preservation stability - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide milk beverage excellent in preservation stability causing no precipitation even if preserved for a long period at high temperature. <P>SOLUTION: The milk beverage (for instance, milk coffee, milk tea and milk cocoa) excellent in preservation stability under high temperature preservation contains lysophosphatidylglycerol. It is preferable that 0.00005-1 mass pt.wt. of lysophosphatidylglycerol is contained based on 100 mass pts.wt. of the milk beverage. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a milk beverage having excellent storage stability at high temperatures. More particularly, the present invention relates to a milk beverage having excellent storage stability, which contains lysophosphatidylglycerol, does not cause precipitation even when sterilized, and does not cause precipitation and oil-off even at high temperature storage.

  Milk drinks such as milk coffee and milk tea are distributed and drunk in a form such as cans, plastic bottles and paper packs. In particular, canned milk drinks are divided into ice type and hot type and sold by vendors. Hot type milk beverages are stored and sold in hot vendors, generally at high temperatures of 50 ° C to 60 ° C. Therefore, precipitation derived from milk components and oil off are problematic.

  A milk drink, especially a canned coffee with milk will be described as an example. In the blending step of mixing the milk component and the coffee extract, since the pH of the coffee extract is low, the protein contained in the milk component coagulates as it is. Therefore, in the blending step, the pH of the coffee extract is adjusted in advance to an appropriate range using baking soda, or the pH of the beverage is adjusted using baking soda after blending. The blended milk coffee is filtered, filled into cans and then sterilized. In this sterilization process, precipitation by heating may occur. In addition, milk-containing canned coffee that has been sterilized and cooled once is stored in a hot bender at a high temperature for a long time in the distribution process, so that the possibility of further precipitation increases. When precipitation occurs in a milk beverage, when the temperature is below room temperature, it solidifies to become a white floating substance, the appearance and taste are lowered, and the commercial value is lowered.

  Various studies have been made to prevent precipitation during sterilization of milk beverages and high-temperature storage, and to improve storage stability. For example, it has been studied to use an emulsifier alone or a combination of an emulsifier and a stabilizer or thickener in a milk beverage (Patent Document 1 and Patent Document 2). Patent Document 1 describes a method of adding an emulsifier having an average HLB of 13.3 to 14.4, which is obtained by combining a sucrose fatty acid ester of HLB 15 to 16 and an emulsifier of HLB 3 to 7. . However, this method has problems such as affecting the taste, causing precipitation during storage at high temperature, and causing oil-off due to the collapse of the emulsified state.

  In Patent Document 2, storage stability is improved by using a combination of sucrose fatty acid esters of HLB 15 to 16 and enzyme-treated lecithin (phosphatidylglycerol) or enzyme-degraded lecithin (soy lecithin treated with phospholipase A2). A method is described. However, the emulsifier of Patent Document 2 has problems such as easy precipitation and a decrease in flavor.

On the other hand, Patent Document 3 describes a method for stabilizing the storage (preventing precipitation) of milked coffee. In this method, first, a strongly basic substance and / or a basic amino acid is added to a coffee extract to neutralize the coffee extract once, and then a milk-derived food is added, followed by heating. In this method, since the pH of the coffee extract is neutralized with a strongly basic substance or the like, there is a problem such as a decrease in flavor.
JP-A-8-228686 JP-A-8-182485 JP 2002-186425 A

  An object of the present invention is to provide a milk beverage that does not deteriorate in flavor even when stored at a high temperature for a long period of time and does not cause precipitation and oil-off.

  The present invention provides a milk beverage containing lysophosphatidylglycerol and having excellent storage stability at high temperatures.

  In a preferred embodiment, lysophosphatidylglycerol is contained in an amount of 0.00005 to 1 part by mass per 100 parts by mass of the milk beverage.

  In another preferred embodiment, the milk beverage is a canned milk beverage.

  In a preferred embodiment, the beverage is a milk beverage selected from the group consisting of milk coffee, milk tea, and milk cocoa.

  The dairy drink of the present invention containing lysophosphatidylglycerol is excellent in storage stability such that the flavor does not deteriorate, and further, precipitation and / or oil-off does not occur even during long-term storage at high temperatures. Moreover, since a natural product is used instead of the conventional synthetic emulsifier, it is excellent in safety.

  In the present invention, the dairy drink means a dairy drink that contains 3% or more of a solid content (milk solid content) derived from a dairy product and is subject to the application of the “Fair Competition Code for Labeling Dairy Beverages”. . Dairy products include milk and products made from milk as raw materials (for example, whole milk powder, skim milk powder, etc.). Examples of the milk drink include, but are not limited to, coffee milk drink, milk tea, cocoa milk drink, fruit milk drink, and egg milk drink. In addition, functional milk beverages in which functional ingredients such as polyunsaturated fatty acids (for example, docosahexaenoic acid, eicosapentaenoic acid, etc.), phospholipids (for example, phosphatidylserine), diacylglycerol, etc. are mixed with these milk beverages are Included in the milk beverage of the invention.

  The lysophosphatidylglycerol used in the present invention has a structure represented by the following formula.

  In this formula, R is a fatty acid residue, and the type thereof is not particularly limited, but is preferably derived from a saturated or unsaturated fatty acid having 14 to 24 carbon atoms. Such a fatty acid residue may be a straight chain or may have a branched chain.

  Such lysophosphatidylglycerol is generally derived from phospholipids. That is, it can be obtained by substituting the base part or phospholipid with glycerol and removing the fatty acid residue at the 2-position of the phospholipid. In general, an enzyme having phosphatidyltransferase activity is allowed to act on a phospholipid in the presence of glycerol to produce phosphatidylglycerol, and then the resulting phosphatidylglycerol is hydrolyzed at the ester bond at the 2-position, Can be obtained by treating with an enzyme capable of releasing.

  Hereinafter, the production of lysophosphatidylglycerol using phospholipids as a raw material will be described based on the following scheme.

  First, as shown in (1), when an enzyme having a phosphatidyl group transfer activity (for example, phospholipase D) is allowed to act on a phospholipid (in this scheme, phosphatidylcholine) in the presence of glycerol, the base portion of the phospholipid (this scheme) Then, a transesterification reaction occurs between choline) and glycerol to produce phosphatidylglycerol. Next, as shown in (2), the phosphatidylglycerol obtained in (1) is treated with an enzyme capable of hydrolyzing the fatty acid ester at position 2 (for example, phospholipase A2) to release the fatty acid at position 2 Gives lysophosphatidylglycerol.

(Starting material: Phospholipid)
The phospholipid used for the preparation of lysophosphatidylglycerol is not particularly limited, and examples thereof include phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, phosphatidic acid, phosphatidylglycerol, and the like. Phosphatidylglycerol is an important phospholipid component in plant chloroplast (chloroplast) and photosynthetic tissue, for example, contained in phospholipids in soybean and sunflower (Lecithins, Bernard F. Szuha1, American oi1 Chemist's Society (1985)).

  In addition to such purified compounds, egg yolk phospholipid, soybean phospholipid, rapeseed phospholipid and the like containing these compounds are used as the phospholipid. For example, egg yolk phospholipids contain 73.0% phosphatidylcholine, 15.0% phosphatidylethanolamine, and 0.6% phosphatidylinositol. Soybean phospholipids contain 38.2% phosphatidylcholine, 17.3% phosphatidylethanolamine, and 16.0% phosphatidyl-inositol (both developed new food functional ingredients, supervised by Akira Ota, CMC, 1996). By replacing the base part of these phosphatidylcholines or phosphatidylethanolamines with glycerol, phosphatidylglycerol is prepared and then converted to lysophosphatidylglycerol. Accordingly, phospholipids containing these compounds are useful as starting materials.

  Moreover, egg yolk phospholipid, soybean phospholipid, rapeseed phospholipid and the like do not have to be highly purified. For example, even if a crude extract or crude product containing components such as proteins, polysaccharides and salts in addition to phospholipids is used as a starting material, these components are included to the extent that they do not inhibit the enzyme reaction. If so, lysophosphatidylglycerol is prepared from the phospholipid. Components other than these phospholipids (for example, proteins, polysaccharides, etc.) can be removed during the recovery or purification of phosphatidylglycerol, which is an intermediate substance leading to lysophosphatidylglycerol, or during the recovery of lysophosphatidylglycerol. Purification of phosphatidylglycerol and lysophosphatidylglycerol is carried out by methods commonly used by those skilled in the art.

  Although phosphatidylglycerol is also used as a starting material, in this case, the first-stage reaction described below is unnecessary.

(First stage: Preparation of phosphatidylglycerol from phospholipid)
In order to prepare phosphatidylglycerol from phospholipid, an enzyme having a phosphatidyl group transfer action (transesterification activity of the phospholipid base moiety and glycerol) is allowed to act on the phospholipid. Examples of the enzyme having a phosphatidyl group transfer action include phospholipase D. Plant-derived phospholipase D (for example, cabbage phospholipase D), microorganism-derived phospholipase D (for example, phospholipase D produced by actinomycetes belonging to Streptomyces) and the like are preferably used. Among these, phospholipase D produced by Streptomyces cinnamoneum is preferably used. Phospholipase D produced by this microorganism has a molecular weight of about 54,000, an optimum pH of 5-6, and an optimum temperature of 40-60 ° C. (Chiaki 0gmo et al. J. Biol. Chem. 125, 263- 269 (1999)).

  As a method for preparing phosphatidylglycerol, there are a one-phase reaction and a two-phase reaction. The one-phase reaction is a reaction in which phospholipid is dispersed in an aqueous solution containing glycerol adjusted to the optimum pH of the enzyme reaction, and phospholipase D is allowed to act on this. The two-phase reaction is a reaction in which phospholipase D acts in a two-phase system of an organic solvent capable of dissolving phospholipid and an aqueous solution containing glycerol. As the organic solvent, a mixed solvent of a nonpolar solvent (eg, hexane, heptane, etc.) and a polar solvent (eg, acetone, ethyl acetate, etc.) is preferably used. In this method, an organic solvent phase obtained by dissolving phospholipid in an organic solvent and an aqueous phase obtained by adding phospholipase to a pH-adjusted glycerin aqueous solution are mixed, and the two phases are mixed and stirred. By this one-phase or two-phase reaction, the transesterification proceeds and phosphatidylglycerol is produced. The produced phosphatidylglycerol is distributed in the organic solvent layer. Therefore, organic solvent extraction is performed in the one-phase reaction, and the organic solvent phase is recovered in the two-phase reaction, and then the organic solvent is removed with an evaporator or the like, thereby recovering phosphatidylglycerol.

(Second stage: Preparation of lysophosphatidylglycerol from phosphatidylglycerol)
In order to prepare lysophosphatidylglycerol from phosphatidylglycerol, an enzyme capable of hydrolyzing the fatty acid ester at the 2-position of phosphatidylglycerol is allowed to act on phosphatidylglycerol. Examples of the enzyme having such an activity include phospholipase A2. Examples of the phospholipase A2 include enzymes derived from animals (for example, porcine pancreas), enzymes derived from microorganisms, and the like. Examples of the enzyme derived from porcine pancreas include lecitase 10L manufactured by Novozymes Japan K.K. Examples of the microorganism-derived enzyme include Lysomax manufactured by Genencor International. Preferably, 10 L of lecitase is used. The optimum pH of lecitase 10L is 6 to 10, and the optimum temperature is 40 to 60 ° C.

  The prepared phosphatidylglycerol is dispersed in water, phospholipase A2 is allowed to act on phosphatidylglycerol, and hydrolyzed to obtain lysophosphatidylglycerol. When phosphatidylglycerol is prepared by a one-phase reaction, phospholipase A2 may be directly added to the reaction solution without isolation of phosphatidylglycerol.

  After the reaction treatment, the temperature of the reaction solution is raised to 70 to 90 ° C. and heat treatment is performed for 5 to 60 minutes. Alternatively, the enzyme can be inactivated by adding a prosthesis to the reaction solution and decomposing phospholipase A2 (and phospholipase D) contained in the reaction solution. Moreover, residual phospholipase D and phospholipase A2 can be removed by treating with an adsorbent such as silica gel, activated carbon or activated clay. Lysophosphatidylglycerol is recovered from the reaction solution in which phospholipase A2 (and phospholipase D) has been deactivated or removed by extraction with an organic solvent such as hexane or heptane, or crystallization with acetone. In addition, lysophosphatidylglycerol is recovered as a precipitate using a metal salt such as calcium chloride. The purification is preferably performed when the amount of fatty acid is large. In this case, it is preferable to use acetone because the fatty acid can be removed by crystallization with acetone and the purification is performed at the same time. Further, after extraction or recovery, purification by chromatography using silica gel or the like may be further performed.

(Preparation of milk beverage)
The obtained lysophosphatidylglycerol is contained in an amount of 0.00005 to 1 part by mass per 100 parts by mass of the milk beverage. Preferably, 0.0001 mass part-0.5 mass part, More preferably, 0.0005-0.1 mass part is contained. By being contained in such an amount, precipitation derived from dairy products does not occur even during heat sterilization or storage at a high temperature of 50 to 60 ° C., preferably 55 to 60 ° C., and has excellent storage stability. Yes. When preparing a milk beverage, homogenization forms an emulsified state in the milk beverage. By adding lysophosphatidylglycerol and emulsifying the emulsion, the emulsion is kept more stable and stored in a high temperature state. However, an effect that oil-off or the like does not occur is also obtained.

  For dairy beverages, in addition to dairy products, beverage ingredients (eg coffee, cocoa, tea etc.) and lysophosphatidylglycerol, sweeteners (eg sugar, isomerized sugar etc.) and antioxidants such as sodium erythorbate Ingredients usually added to beverages such as flavorings such as coffee flavors and milk flavors are added. Although there is no restriction | limiting in the order which adds these components, For example, it prepares with the following method. First, lysophosphatidylglycerol is dissolved in water together with a sweetener added as necessary to prepare an aqueous solution. A dairy product (for example, milk, whole milk powder, skim milk powder, etc.) is added to this aqueous solution and stirred. A separately prepared beverage component is added thereto, heated to 70 to 85 ° C., and stirred with a homogenizer to obtain an emulsion. The treatment with the homogenizer may be performed once or twice or more. During or after homogenization, the temperature is further raised to, for example, about 90 ° C., and then filled into a container (eg, can, paper pack, etc.). After filling, the milk beverage is sterilized together with the container (for example, 120-124 ° C., retort sterilization for 20 minutes). In this way, a milk beverage is prepared.

  In addition, when the pH of a drink component is low, the drink component and dairy product which adjusted pH previously are mixed, or pH is adjusted after mixing a drink component and dairy product. For example, since the coffee extract has a low pH, the pH of the coffee extract can be adjusted between 6 and 7, preferably between 6.5 and 7 using a sodium bicarbonate solution, or the pH can be adjusted after mixing. preferable.

  The milk beverage thus prepared does not cause precipitation even when stored at a high temperature of 50 to 60 ° C. Further, a milk beverage in which the emulsified state is stably maintained even at a high temperature is provided.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated, this invention is not restrict | limited to these Examples.

(Preparation Example 1 of Lysophosphatidylglycerol)
27 g of lecithin (SLP-PC70: manufactured by True Lecithin Industry Co., Ltd.) containing 70% by mass or more of phosphatidylcholine was dissolved in 300 ml of a mixed solvent of heptane / acetone (volume ratio 80/20). On the other hand, phospholipase D (manufactured by Nagase ChemteX Corp.) 17,550 U was dissolved in 50 ml of a glycerol solution mixed so that the final concentration was 0.6 M acetate buffer (pH 4) and 7.2 M glycerol to prepare an aqueous solution. did.

  1 U of phospholipase D refers to the amount of enzyme required to liberate 1 μmol of choline at 37 ° C. for 1 minute using phosphatidylcholine as a substrate.

  The obtained mixed organic solvent and aqueous solution were mixed in a two-phase system and stirred at 30 ° C. for 5 hours. After completion of the reaction, 35 g of sodium chloride was added to the reaction solution, dissolved, separated into an organic solvent phase and an aqueous phase, and the organic solvent phase was recovered. A solid substance containing 70 to 90% by mass of phosphatidylglycerol was obtained by removing the organic solvent at 60 ° C. using an evaporator.

20 g of the obtained solid content was dispersed in 0.2 M Tris-HCl buffer (pH 8) containing 6 mM CaCl ₂ . The solution amount was adjusted to 80 ml, phospholipase A2 (Novozymes Japan K.K. lecitase 10L: 10,000 IU / g) 24,000 IU was added, and the treatment at 50 ° C. for 5 hours was carried out to achieve 90% or more. A dispersion containing lysophosphatidylglycerol (ie, 90% or more of phosphatidylglycerol was lysed) was obtained. Three times the volume of ethanol was added to the dispersion to precipitate and remove phospholipase A. The ethanol solution after removing the precipitate is concentrated to a volume of about 1/3, and to the resulting concentrate is added 3 times the volume of acetone to crystallize lysophosphatidylglycerol, It was collected.

  In addition, 1 IU of phospholipase A2 refers to the amount of enzyme required to liberate 1 μmol of fatty acid at 37 ° C. for 1 minute using phosphatidylcholine as a substrate.

  The purity of lysophosphatidylglycerol was measured according to the method for measuring the phospholipid composition described in the standard oil analysis method (edited by the Japan Oil Chemists' Society, 1996 version 4.3.3.1-1996).

(Preparation Example 2 for Lysophosphatidylglycerol)
Glycerol solution in which 27 g of lecithin (SLP-PC70: manufactured by True Lecithin Industry Co., Ltd.) containing 70% by mass or more of phosphatidylcholine was mixed so that the final concentration was 0.2 M acetate buffer (pH 5) and 3.3 M glycerol. After dispersing in 50 ml, 2,700 U of phospholipase D (manufactured by Nagase ChemteX Corporation) was added and reacted at 50 ° C. for 5 hours.

  Next, after adjusting the pH to 7.6 with 2N NaOH, 24,000 IU of phospholipase A2 (Novozymes Japan Co., Ltd. Lecitase 10L: 10,000 IU / g) is added, and the treatment is performed at 50 ° C. for 5 hours. As a result, a dispersion containing 90% or more of lysophosphatidylglycerol (that is, 90% or more of phosphatidylglycerol was lysed) was obtained. Three times the volume of ethanol was added to the dispersion to precipitate and remove phospholipase A. The ethanol solution after removing the precipitate was concentrated to a volume of about 1/3, and 3 times the volume of acetone obtained was added to crystallize and collect lysophosphatidylglycerol.

(Example 1)
To 15 parts by weight of water, 5 parts by weight of sugar and lysophosphatidylglycerol powder prepared in Preparation Example 1 are added in the amounts shown in Table 1 (unit is parts by weight per 100 parts by weight of milk beverage), and at 70 ° C. for 10 minutes. Dissolved with stirring. After dissolution, 7 parts by mass of milk was added, and the mixture was further stirred for 10 minutes and mixed. Next, 65 parts by mass of a coffee extract (containing 12% by mass of solid) whose pH was adjusted to 6.7 to 6.8 in advance with a 10% by mass sodium bicarbonate solution was added and stirred. The mixture is heated to 80 ° C., adjusted to 100 parts by mass with water, homogenized at an intensity of 150 kg / cm ² , heated to 90 ° C., then filled into a container, and a retort sterilizer is used. Was sterilized (120 ° C., 20 minutes). By this method, canned coffee with milk containing 7.8% by mass of the coffee extract in terms of solid content was obtained.

  The obtained canned coffee with milk was stored at 60 ° C. for 90 days and then opened, and the state of precipitation and oil-off was visually observed. The results are shown in Table 1.

The evaluation of precipitation was performed according to the following criteria, and the corresponding symbols were displayed in Table 1.
○: No precipitation is observed △: Precipitation is slightly observed but does not affect the commercial value ×: Precipitation is clearly recognized and affects the commercial value

The oil-off evaluation was performed according to the following criteria, and the corresponding symbols were displayed in Table 1.
○: No oil-off △: Oil-off is slightly observed but does not affect the commercial value ×: Oil-off is clearly recognized and affects the commercial value

(Comparative example)
Instead of lysophosphatidylglycerol, SLP white lysozyme (manufactured by Tsurulecithin Industry Co., Ltd.), which is lysolecithin, was added in an amount corresponding to lysophosphatidylglycerol of the example, respectively. Milk canned coffee was prepared and evaluated. The results are shown in Table 1.

  The result of Table 1 shows that by adding lysophosphatidylglycerol, no precipitation occurred and the occurrence of oil-off was suppressed in high-temperature storage of canned coffee with milk. This effect was far superior to lysolecithin. In addition, both precipitation and oil-off were observed in the milk canned coffee containing no lysophosphatidylglycerol and lysolecithin.

(Example 2)
After mixing 6 parts by weight of sugar, 0.5 parts by weight of whole milk powder, 0.125 parts by weight of skim milk powder, and 0.0005 parts by weight of lysophosphatidylglycerol powder prepared in Preparation Example 2 and adding to 20 parts by weight of water And dissolved at 70 ° C. for 10 minutes with stirring. To this solution, 65 parts by mass of a coffee extract (containing 12% by mass of solid content) was added and mixed, and the pH was adjusted to 6.7 to 6.8 with a 10% by mass sodium bicarbonate solution. Water was added to adjust the whole to 100 parts by mass, homogenized with an intensity of 150 kg / cm ² , filled in a container, and sterilized using a retort sterilizer (124 ° C., 20 minutes). By this method, canned coffee with milk containing 7.8% by mass of the coffee extract in terms of solid content was obtained.

  The canned coffee with milk was stored at 60 ° C. for 4 weeks and then opened, and the state of precipitation and oil-off was visually observed. Neither precipitation nor oil-off was observed. In addition, generation | occurrence | production of precipitation was recognized when the lysolecithin (SLP white lyso) used as a comparison instead of lysophosphatidylglycerol was used.

(Example 3)
8 parts by mass of commercially available black tea was added to 150 parts by mass of hot water to prepare a black tea extract. Separately, 8 parts by weight of sugar, 2 parts by weight of whole milk powder, and 0.0001 parts by weight of lysophosphatidylglycerol powder prepared in Preparation Example 2 were added, and the mixture was added to 50 parts by weight of water. Dissolved with stirring for a minute. 20 parts by mass of the black tea extract was added to and mixed with the solution, and the pH was adjusted to 6.7 to 6.8 with a 10% by mass sodium bicarbonate solution. Water was added to adjust the whole to 100 parts by mass, homogenized with an intensity of 150 kg / cm ² , filled into a container, and sterilized using a retort sterilizer (121 ° C., 20 minutes).

  The canned coffee was stored at 60 ° C. for 2 months and then opened, and the state of precipitation and oil-off was visually observed. Neither precipitation nor oil-off was observed. In addition, when the same amount of lysolecithin (SLP white lyso) used as a comparison was used instead of lysophosphatidylglycerol, precipitation and oil-off were observed.

  The dairy drink containing lysophosphatidylglycerol of the present invention does not deteriorate in flavor, does not cause precipitation even after long-term storage at a high temperature of 50 to 60 ° C., and does not cause oil-off. For this reason, the milk drink of this invention is suitable for sale by hot vendors, such as a vending machine.

Claims (4)

  A milk drink containing lysophosphatidylglycerol and having excellent storage stability at high temperatures.   The dairy drink according to claim 1, wherein lysophosphatidylglycerol is contained in an amount of 0.00005 to 1 part by mass per 100 parts by mass of the dairy drink.   The milk drink of Claim 1 or 2 whose said milk drink is a canned milk drink.   The milk beverage according to any one of claims 1 to 3, wherein the beverage is a milk beverage selected from the group consisting of milk coffee, milk tea, and milk cocoa.