JP2006304782A - Method for producing oil-in-water emulsifion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing an oil-in-water emulsifion containing micelle-like protein and having a median diameter of oil drop of 0.3-5.0 μm to have excellent preservation stability, without using a salt, which melts proteins, such as phosphate and citrate, an emulsifier and a pH modifier. <P>SOLUTION: This method for producing the oil-in-water emulsifion which contains micelle-like protein and has 20-60 wt.% of oil and fat comprises using no emulsifier or protein melting salt. It is possible to produce the oil-in-water emulsifion which has long term preservation stability and excellent flavor by gradually lessening the median diameter of oil drops contained in an oil-in-water emulsified substance as the raw material, and bringing the final median diameter to a desired particle diameter of 0.3-5.0 μm. Furthermore, with respect to a fresh cream for which an additive such as an emulsifier cannot be used, it is possible to produce a fresh cream improved in its preservation stability and having a long palatable period by making the particle diameter of fat drops smaller without addition of an emulsifier. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing an oil-in-water emulsion containing a micellar protein such as whipped cream and cream for kneading used in the production of cakes, desserts and the like.

  Oil-in-water emulsions containing micellar proteins such as whipped creams and creams used in the manufacture of cakes and desserts usually contain multiple emulsifiers and inorganic compounds such as protein melts. , Pre-emulsification, homogenization, sterilization, homogenization, cooling, and aging. In the oil-in-water emulsion, when the particle size of oil droplets is large, oil-water separation is likely to occur during storage or transportation (hereinafter referred to as “creaming”), and there is a problem in storage stability. Therefore, by the homogenization process, the particle size of the oil droplet is reduced so that the final median diameter is 5.0 μm or less, thereby preventing creaming and ensuring long-term storage stability.

  A high-pressure homogenizer is often used for the homogenization treatment of the oil-in-water emulsion for reducing the oil droplets as described above. However, if the oil-in-water emulsion containing micellar protein, such as the above cream, is homogenized by a high-pressure homogenizer and the particle size of the oil droplets is made too small at once, the micellar protein becomes oil droplets (fat globules) It has been difficult to obtain a good emulsion because the oil droplets aggregated immediately after the homogenization treatment and the viscosity of the emulsion increased. Therefore, in order to produce an oil-in-water emulsion containing a micellar protein and having a final median diameter of oil droplets as small as 5.0 μm or less and having good storage stability, There is a need to add pH adjusters.

  Examples of the emulsifier include sucrose fatty acid ester, lecithin, glycerin fatty acid ester, polyglycerin fatty acid ester, sorbitan fatty acid ester, propylene glycol fatty acid ester, and organic acid fatty acid ester. As the protein molten salt, phosphate, citrate and the like are used. Further, as the pH adjuster, acids such as succinic acid, lactic acid, phosphoric acid, citric acid, carbonic acid and acetic acid and salts of these acids are used. However, the use of these emulsifiers and protein molten salts has disadvantages such as loss of flavor due to their own taste, and aversion due to the recent increase in safety awareness of foods. Things are longing for.

  In addition, a cream (hereinafter referred to as “fresh cream”) defined as “raw milk, milk or special milk from which components other than milk fat have been removed” by a ministerial ordinance such as milk is usually heated, separated, Manufactured through sterilization, homogenization, cooling, aging and filling processes. Fresh cream oil droplets (fat spheres) have a median diameter of about 3 μm. In the case of this fresh cream, creaming during storage and transportation is prevented to ensure long-term storage stability and solidification. In order to suppress this, it is desirable to further reduce the particle size of the fat globules. However, in the case of fresh cream, since there is the definition as described above, additives such as emulsifiers cannot be used at all. For this reason, when homogenizing the fresh cream, it is processed at a low pressure, and the particle diameter of the fat globules cannot be reduced sufficiently. Such a fresh cream that is homogenized at a low pressure and has a large fat globule particle size has the property of causing creaming during storage and transportation, and the surface layer is easily solidified. Therefore, the expiration date is set short.

Regarding an oil-in-water emulsion that does not use an emulsifier, a protein molten salt, or the like, there is a method of using a milk component with a reduced calcium content (Patent Document 1). However, this method requires the use of an ion exchange column, an electrodialyzer, or the like in order to reduce calcium in milk components, which is not efficient in industrial production and is not easy to implement. It was. In addition, there are a method of using egg yolk oil and a metal salt of casein in combination (Patent Document 2) and a method of using sugar alcohol (Patent Document 3). However, the egg yolk oil, the metal salt of casein, and the sugar alcohol each have a unique flavor, and the flavor of the emulsion using the same is greatly affected. Moreover, these methods cannot be applied to the fresh cream.
JP 2000-333602 A JP-A-11-89531 Japanese Patent Laid-Open No. 10-304821

  In view of the problems in the production of an oil-in-water emulsion as described above, the present invention contains a micellar protein, the median diameter of oil droplets is 5.0 μm or less, has long-term storage stability, and flavor. Oil-in-water emulsions that are also excellent without the use of protein melt salts such as phosphates and citrates, emulsifiers and pH adjusters, and the use of additives such as the above-mentioned emulsifiers Even in the case of fresh cream that cannot be used, the storage stability is improved by making the particle size of the fat globules smaller without using such additives, thereby enabling the production of fresh cream with a long shelf life. An object of the present invention is to provide a method for producing an oil-in-water emulsion.

  The method for producing an oil-in-water emulsion according to the present invention, which achieves the above object, contains a micellar protein, the median diameter of oil droplets is 0.3 to 5.0 μm, and the fat content is 20 A method for producing an oil-in-water emulsion of ˜60% by weight, wherein the median diameter of the oil droplets contained in the oil-in-water emulsion as a raw material is gradually reduced, and the final median diameter of the oil droplets is reduced. The desired particle size is in the range of 0.3 to 5.0 μm.

  As a method of gradually reducing the median diameter of oil droplets, the median diameter of oil droplets is gradually reduced by homogenizing the oil-in-water emulsion used as a raw material multiple times. It is preferable to repeat the homogenization process until the final median diameter of the oil droplets reaches a desired particle diameter.

  In the above case, it is preferable to repeat the homogenization by sequentially increasing the pressure setting until the median diameter of the oil droplets reaches a desired particle diameter.

  As a raw material when producing an oil-in-water emulsion in the present invention, an oil-in-water emulsion prepared by pre-emulsifying at least oil and micellar protein and water or a fresh cream can be used as an essential component. .

  When the oil-in-water emulsion used as a raw material is a fresh cream, it is preferable to repeat the homogenization treatment until the final median diameter of oil droplets (fatty spheres) is 3.0 μm or less.

  The method for producing an oil-in-water emulsion of the present invention can be carried out without adding an emulsifier, a protein molten salt and a pH adjuster.

  According to the method for producing an oil-in-water emulsion of the present invention as described above, the final median of oil droplets can be obtained without using protein molten salts such as phosphates and citrates, emulsifiers and pH adjusters. An oil-in-water emulsion having a diameter of 0.3 to 5.0 μm and containing a micellar protein can be produced, and an oil-in-water emulsion having a long-term storage stability and a good flavor is obtained.

  In addition, when fresh cream is used as a raw material, the final median diameter of oil droplets (fat globules) can be reduced compared to conventional products, and it has excellent storage stability and has a longer shelf life than conventional products. Can be manufactured.

  In the present invention, addition of the above-mentioned emulsifier, protein molten salt, and pH adjuster is not excluded. However, as described above, according to the present invention, long-term storage stability can be ensured by gradually reducing oil droplets and fat globules of oil-in-water emulsions and fresh creams without using these additives. Can do. Therefore, it is a preferable aspect not to use any additive that affects the flavor from the viewpoint of the flavor of the resulting oil-in-water emulsion or fresh cream.

Hereinafter, the present invention will be described in more detail.
The oil-in-water emulsion in the present invention is an O / W emulsion in which oil droplets are dispersed in water, and essential components include fats and oils, water, and protein. The other components are not limited at all. In addition, a fresh cream defined as “raw milk, milk, or special milk from which components other than milk fat have been removed” according to a ministerial ordinance such as milk is also included in the oil-in-water emulsion of the present invention.

  Accordingly, examples of the raw material emulsion in the method for producing an oil-in-water emulsion of the present invention include an oil-in-water emulsion prepared by pre-emulsifying at least oil and fat and micellar protein and water, and a fresh cream.

  The oil and fat is not particularly limited as long as it is edible. For example, rapeseed oil, soybean oil, sunflower seed oil, cottonseed oil, peanut oil, rice bran oil, corn oil, safflower oil, olive oil, kapok oil, sesame oil, evening primrose oil Plant oils such as palm oil, shea fat, monkey fat, cacao butter, coconut oil, palm kernel oil, and animal fats such as milk fat, beef tallow, pork fat, fish oil, whale oil, etc. Alternatively, mixed oils or processed oils and fats that have been cured, fractionated, transesterified, or the like can be used.

  The content of fat / oil is preferably 20 to 60% by weight, more preferably 30 to 50% by weight, based on the whole oil-in-water emulsion. If the fat or oil is less than 20% by weight, even if a high pressure homogenizer treatment is performed at a high pressure, there are many cases where the aggregation of oil droplets and the thickening phenomenon of the emulsion itself do not occur. Not noticeable. Further, if the fat and oil is more than 60% by weight, there is a possibility that the aggregation of the oil droplets and the thickening phenomenon of the emulsion may occur even if the method of decreasing the median diameter of the oil droplets step by step of the present invention is used. The median diameter may not be reduced.

  A micellar protein refers to a protein larger than the size of a normal protein, in which single protein molecules are bound together by some action. For example, casein micelles composed of casein protein and phosphate crosslinks can be mentioned. Examples of powders containing these micellar proteins include skim milk powder, whole milk powder, cream powder, buttermilk powder, milk protein concentrate, milk fat globule membrane protein, and the like. Fresh cream is an oil-in-water emulsion containing micellar protein. Moreover, in this invention, it is also possible to add proteins other than the said micelle-like protein in an oil-in-water emulsion, and these proteins are not limited at all.

  The oil-in-water emulsion used as a raw material emulsion in the method for producing an oil-in-water emulsion of the present invention contains the above fats and micelles as essential components and was prepared by pre-emulsification with water. Oil-in-water emulsions and fresh creams can be used. The preliminary emulsification method is not particularly limited. For example, the preliminarily emulsified with a homomixer is prepared by mixing an oil phase portion made of edible oil and fat and an aqueous phase portion in which micellar protein is dissolved in a pre-emulsification tank. it can.

  In the production method of the present invention, the median diameter of the oil droplets contained in the oil-in-water emulsion as a raw material as described above is gradually reduced, but the final median diameter of the oil droplets is 0.3 to 5. It is preferable to reduce it to 0 μm. Furthermore, the final median diameter of the oil droplets is more preferably 0.3 to 4.0 μm, further preferably 0.3 to 3.0 μm, and most preferably 0.3 to 2.5 μm. Oil droplets smaller than 0.3 μm are substantially impossible to produce because they have the same size as micellar proteins. If it is larger than 5.0 μm, the aggregation and thickening phenomenon of oil droplets may not occur without using the means of the present invention, and the effect of carrying out the present invention is not remarkable, and if the oil droplets are large, creaming may occur. It is easy to occur and it is difficult to ensure long-term storage stability. As the median diameter of the oil droplets is in a more preferable range, creaming does not easily occur and long-term storage stability can be ensured. In the case of fresh cream, the oil droplets (fatty spheres) are usually smaller than 5.0 μm, but according to the present invention, the oil droplets (fat spheres) are further reduced to prevent the occurrence of creaming and stable for long-term storage. By ensuring the property and suppressing the solidification, it is possible to provide a fresh cream having a long shelf life as compared with the past.

  In addition, the median diameter of the oil droplet referred to in the present invention corresponds to 50% of a volume-based integrated distribution curve measured with a laser diffraction / scattering particle size distribution measuring device LA-920 (manufactured by Co., Ltd.). The particle size to be used.

  In the method for producing an oil-in-water emulsion of the present invention, the method for gradually reducing the particle size (median diameter) of oil droplets is not particularly limited, and a method of performing homogenization treatment multiple times with a high-pressure homogenizer, In addition, there is a method in which other refinement and homogenization methods are combined with a homogenization treatment using a high-pressure homogenizer. For example, after miniaturization by other miniaturization and homogenization methods, processing once or multiple times with a high-pressure homogenizer, or after processing once or multiple times with a high-pressure homogenizer, other miniaturization And performing the treatment by a homogenization method.

  The homogenization by the high-pressure homogenizer treatment means that the emulsion is pressurized to a high pressure, and the oil droplets are pulverized to be dispersed and emulsified using a shearing force when passing through a slit (gap). Examples of the apparatus for performing the high-pressure homogenizer treatment include a homogenizer HV-A (manufactured by Izumi Food Machinery Co., Ltd.), a homogenizer H-20 type (manufactured by Sanwa Machinery Co., Ltd.), and the like.

  The pressure setting of the high-pressure homogenizer is preferably set to a level that does not cause the aggregation of oil droplets and the thickening phenomenon of the emulsion immediately after the treatment, which can be said to be a condition in which a sudden change in the median diameter before and after the treatment hardly occurs. As the median diameter decreases, the aggregation and thickening phenomenon hardly occur even when the set pressure is increased, and the median diameter can be set to a desired size. Even if aggregation or thickening occurs immediately after the treatment, there is no problem as long as the viscosity is such that the next treatment can be performed. In that case, the next treatment is the same as or lowering the set pressure of the previous treatment, so that the agglomerated oil droplets are loosened, the viscosity of the emulsion is lowered, and the median diameter is the agglomeration and thickening phenomenon. Smaller than before waking up.

  Examples of the method of repeating the homogenization treatment multiple times include the method of processing multiple high-pressure homogenizers, the method of processing multiple high-pressure homogenizers with different set pressures, and the emulsion once processed before the high-pressure homogenizer. There is a method of feeding back and circulating the emulsion. Furthermore, a method of increasing the set pressure stepwise while circulating can be exemplified.

  Other than the high-pressure homogenizer treatment, there is no limitation on the method of miniaturization and homogenization. For example, TK Homomixer (Special Machine Industries Co., Ltd.), Ultra Disperser (Hiscotron (Nihon Medical Science Instrument Co., Ltd.)), Claremix (M Technique Co., Ltd.), Philmix (Special Machine) Kogyo Co., Ltd., in-line mixers (Silverson Machines, Inc) and other emulsification / miniaturization methods, emulsification / dispersion sterilizers (eg, steam blown direct heating method), jetting Examples include a method based on a physical action, an ultrasonic emulsification method, an intermittent shaking method, and a colloid mill emulsification method.

  As for the sterilization and sterilization treatment of the oil-in-water emulsion produced by the method of the present invention, the raw material emulsion may be homogenized and then sterilization and sterilization treatment may be performed, or sterilization and sterilization treatment may be performed in advance. Later, a homogenization process may be performed. In this case, sterilization and sterilization methods are not particularly limited. For example, direct heat sterilization (injection type, infusion type), indirect heat sterilization (plate type, tubular type, shell & tube type, surface scraping type), internal heat sterilization (energization type, microwave type, high frequency type, Far-infrared type), superheated steam sterilization, retort sterilization, ultraviolet sterilization, high-pressure sterilization, electrolytic magnetic field sterilization, radiation sterilization, chemical sterilization, and the like. Moreover, it can carry out also by the method which combined them.

  The oil-in-water emulsion produced by the method of the present invention is, for example, whipped cream, coffee cream, ice cream, soft cream premix, bread, confectionery, ham, sausage, meat, fish meat, other processed foods, etc. It is used for oils and fats for kneading, mayonnaise, dressing, cheese-like food, flour paste, filling, topping, sand, spread and the like.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

Example 1
An oil phase part was prepared by temperature-adjusting 35 parts by weight of hardened rapeseed oil (rising melting point 22.0 ° C) and 5 parts by weight of hardened palm oil (rising melting point 36 ° C) to 65 ° C. On the other hand, 5 parts by weight of skim milk powder was dissolved in 55 parts by weight of water at 60 ° C. to obtain an aqueous phase part. The oil phase and the aqueous phase were mixed in a pre-emulsification tank at 60 ° C., and pre-emulsified at 7000 rpm with a TK homomixer (M-A manufactured by Tokushu Kika Kogyo Co., Ltd.). The oil droplet median diameter of the pre-emulsified liquid was taken as the initial particle diameter and measured with a laser diffraction / scattering type particle size distribution measuring apparatus (manufactured by Co., Ltd., hereinafter the same), and was 21.1 μm. This pre-emulsified solution was subjected to a high-pressure homogenizer treatment once each under pressure conditions of 1 Mpa and 4 Mpa using a homogenizer (HV-A manufactured by Izumi Food Machinery Co., Ltd., hereinafter simply referred to as a homogenizer) to obtain an emulsion. . This emulsion was used as an intermediate emulsion, and the oil droplet median diameter was set as an intermediate particle diameter, which was measured by a laser diffraction / scattering type particle size distribution analyzer. This intermediate emulsion was subjected to a high-pressure homogenizer treatment using a homogenizer under a pressure condition of 3 Mpa. Then, after sterilizing for 30 seconds at 130 ° C. with a plate heat exchange sterilizer, the sample was cooled to 5 ° C. with a cooling plate to obtain Sample 1. The oil droplet median diameter of Sample 1 was measured with a laser diffraction / scattering particle size distribution analyzer and found to be 4.0 μm. The oil droplet median diameter was defined as the final particle diameter. Sample 1 was a good liquid emulsion without thickening.

(Example 2)
A pre-emulsified liquid (initial particle size 21.1 μm) prepared in the same manner as in Example 1 was treated once under a pressure condition of 1 Mpa, 4 Mpa and 3 Mpa using a homogenizer, and an intermediate emulsion having an intermediate particle size of 4.0 μm. A liquid was obtained. This intermediate emulsion was treated with a homogenizer under a pressure condition of 8 Mpa, then sterilized and cooled in the same manner as in Example 1 to obtain Sample 2. The final particle size was 3.8 μm. Sample 2 was also a good liquid emulsion without thickening.

(Comparative Example 1)
A preliminary emulsion (initial particle size 21.1 μm) prepared in the same manner as in Example 1 was used as an intermediate emulsion (intermediate particle size 21.1 μm). The intermediate emulsion was treated under a pressure condition of 1 Mpa using a homogenizer, then sterilized and cooled in the same manner as in Example 1 to obtain Sample 3. The final particle size was 10.3 μm. Sample 3 was also a good liquid emulsion without thickening. However, the sample 3 was stored at 4 ° C. for 2 weeks and examined for creaming. As a result, a cream layer was formed on the upper part, and the result was not good (Comparative Example 1-1). Therefore, when trying to make the particle size smaller than the final particle size (10.3 μm) and subjecting the intermediate emulsion to a high pressure homogenizer treatment with a pressure condition higher than 1 Mpa, oil droplets aggregate and thicken. Thus, an emulsified unstable emulsion was obtained (Comparative Example 1-2).

(Comparative Example 2)
A preliminary emulsion (initial particle size 21.1 μm) prepared in the same manner as in Example 1 was treated once with a homogenizer at a pressure of 1 Mpa to obtain an intermediate emulsion having an intermediate particle size of 9.3 μm. This intermediate emulsion was treated with a homogenizer under a pressure condition of 4 Mpa, then sterilized and cooled in the same manner as in Example 1 to obtain Sample 4. The final particle size was 6.5 μm. Sample 4 was also a good liquid emulsion without thickening. However, when this sample 4 was examined for creaming in the same manner as in Comparative Example 1, a cream layer was formed on the upper portion, which was not a good result (Comparative Example 2-1). Then, when trying to make the particle size smaller than the final particle size (6.5 μm), the intermediate emulsion was subjected to a high pressure homogenizer treatment with a pressure condition higher than 4 Mpa, and oil droplets aggregated and increased in viscosity. Thus, an emulsified unstable emulsion was obtained (Comparative Example 2-2).

(Example 3)
A preliminary emulsified liquid was prepared in the same manner as in Example 1 except that the skim milk powder was changed to buttermilk powder (initial particle size: 18.8 μm). This preliminary emulsified liquid was treated 8 times under a pressure condition of 0 Mpa (valve fully opened) using a homogenizer to obtain an intermediate emulsified liquid having an intermediate particle diameter of 5.2 μm. This intermediate emulsion was further treated with a homogenizer under a pressure condition of 0 Mpa (valve fully opened), then sterilized and cooled in the same manner as in Example 1 to obtain Sample 5. The final particle size was 4.8 μm. Sample 5 was also a good liquid emulsion without thickening.

Example 4
A preliminary emulsion was prepared in the same manner as in Example 3 (initial particle size: 18.8 μm). This preliminary emulsified liquid was treated 9 times under a pressure condition of 0 Mpa (valve fully opened) using a homogenizer to obtain an intermediate emulsified liquid having an intermediate particle diameter of 4.8 μm. This intermediate emulsion was treated with a homogenizer at a pressure condition of 1 Mpa, then sterilized and cooled in the same manner as in Example 1 to obtain Sample 6. The final particle size was 3.8 μm. Sample 6 was also a good liquid emulsion without thickening.

(Example 5)
A preliminary emulsion was prepared in the same manner as in Example 3 (initial particle size: 18.8 μm). This preliminary emulsified liquid was treated 9 times under a pressure condition of 0 Mpa (valve fully opened) using a homogenizer, and then treated once under a pressure condition of 1 Mpa to obtain an intermediate emulsion having an intermediate particle diameter of 3.2 μm. This intermediate emulsion was treated with a homogenizer under a pressure condition of 3 Mpa, then sterilized and cooled in the same manner as in Example 1 to obtain Sample 7. The final particle size was 3.1 μm. Sample 7 was also a good liquid emulsion without thickening.

(Example 6)
A preliminary emulsion was prepared in the same manner as in Example 3 (initial particle size: 18.8 μm). This preliminary emulsified liquid was treated 9 times under a pressure condition of 0 Mpa (valve fully opened), once at 1 Mpa, once at 3 Mpa using a homogenizer to obtain an intermediate emulsion having an intermediate particle diameter of 2.96 μm. This intermediate emulsion was treated with a homogenizer under a pressure condition of 4 Mpa, then sterilized and cooled in the same manner as in Example 1 to obtain Sample 8. The final particle size was 2.82 μm. Sample 8 was also a good liquid emulsion without thickening. Moreover, when creaming was investigated about the sample 8 like the comparative example 1, the cream layer was not formed in the upper part but the favorable result was obtained.

(Comparative Example 3)
A preliminary emulsion was prepared in the same manner as in Example 3 (initial particle size: 18.8 μm). The preliminary emulsion was defined as an intermediate emulsion (intermediate particle size: 18.8 μm). The intermediate emulsion was treated with a homogenizer under a pressure condition of 0 Mpa (valve fully opened), then sterilized and cooled in the same manner as in Example 1 to obtain Sample 9. The final particle size was 10.6 μm. Sample 9 was also a good liquid emulsion without thickening. However, this sample 9 was examined for creaming in the same manner as in Comparative Example 1. As a result, a cream layer was formed on the upper portion, and the result was not satisfactory (Comparative Example 3-1). Therefore, when an attempt was made to make the particle size smaller than the final particle size (10.6 μm), the intermediate emulsion was subjected to a high pressure homogenizer treatment with a pressure condition higher than 0 Mpa, and oil droplets aggregated and increased in viscosity. Thus, an emulsified unstable emulsion was obtained (Comparative Example 3-2).

(Comparative Example 4)
A preliminary emulsion was prepared in the same manner as in Example 3 (initial particle size: 18.8 μm). This preliminary emulsion was treated with a homogenizer at a pressure condition of 0 Mpa (valve fully opened) to obtain an intermediate emulsion having an intermediate particle size of 10.6 μm. This intermediate emulsion was treated with a homogenizer under a pressure condition of 0 Mpa (valve fully opened), then sterilized and cooled in the same manner as in Example 1 to obtain Sample 10. The final particle size was 8.0 μm. Sample 10 was also a good liquid emulsion without thickening. However, this sample 9 was examined for creaming in the same manner as in Comparative Example 1. As a result, a cream layer was formed on the upper portion, and the result was not satisfactory (Comparative Example 4-1). Therefore, when trying to make the particle size smaller than the final particle size (8.0 μm), and the high pressure homogenizer treatment is performed on the intermediate emulsion with the pressure condition higher than 0 Mpa, oil droplets aggregate and thicken. As a result, the emulsion became unstable (Comparative Example 4-2).

(Example 7)
A preliminary emulsion (initial particle size 24.3 μm) prepared in the same manner as in Example 1 was circulated for 10 minutes using a homogenizer with a pressure condition of 2 Mpa to obtain an intermediate emulsion having an intermediate particle size of 3.2 μm. . The intermediate emulsion was circulated for 16 minutes using a homogenizer with a pressure condition of 4 Mpa, then sterilized and cooled in the same manner as in Example 1 to obtain Sample 11. The final particle size was 2.2 μm. Sample 11 was also a good liquid emulsion without thickening. Moreover, when creaming was investigated about the sample 11 like the comparative example 1, the cream layer was not formed in the upper part but the favorable result was obtained.

(Example 8)
The oil phase part of the blend is 35 parts by weight of hardened rapeseed oil (rising melting point 22.0 ° C) and 5 parts by weight of hardened palm oil (rising melting point 36 ° C), and the aqueous phase part is changed to 15 parts by weight of skim milk powder and 45 parts by weight of water. A preliminary emulsion was prepared in the same manner as in Example 1 except that the initial particle size was 25.4 μm. This preliminary emulsion was treated twice with a homogenizer under pressure conditions of 0 Mpa (valve fully opened) and twice at 1 Mpa to obtain an intermediate emulsion having an intermediate particle size of 5.8 μm. This intermediate emulsion was further treated twice under a pressure condition of 2 Mpa using a homogenizer, then sterilized and cooled in the same manner as in Example 1 to obtain Sample 12. The final particle size was 3.5 μm. Sample 12 was also a good liquid emulsion without thickening.

Example 9
A preliminary emulsion was prepared in the same manner as in Example 8 (initial particle size: 25.4 μm). Using a homogenizer, this pre-emulsified solution was subjected to 2 times at a pressure condition of 0 Mpa (valve fully opened), 2 times at 1 Mpa, 2 times at 2 Mpa, 2 times at 4 Mpa, 2 times at 6 Mpa, 2 times at 8 Mpa, 2 times at 10 Mpa. This was treated twice, twice at 12 Mpa, and twice at 15 Mpa to obtain an intermediate emulsion having an intermediate particle size of 1.5 μm. The intermediate emulsion was further treated twice under a pressure condition of 20 Mpa using a homogenizer, and then sterilized and cooled in the same manner as in Example 1 to obtain Sample 13. The final particle size was 1.3 μm. Sample 13 was also a good liquid emulsion without thickening. Moreover, when creaming was investigated about the sample 13 like the comparative example 1, the cream layer was not formed in the upper part but the favorable result was obtained.

(Example 10)
After fresh cream (oil content 47% by weight, initial particle size 3.2 μm) was adjusted to 60 ° C., it was circulated for 8 minutes using a homogenizer with a pressure condition of 3 Mpa to obtain an intermediate emulsion having an intermediate particle size of 1.9 μm. Obtained. This intermediate emulsion was further circulated for 1 minute using a homogenizer with a pressure condition of 4 Mpa. Thereafter, the sample 14 was obtained by sterilization treatment and cooling in the same manner as in Example 1. The final particle size was 1.7 μm. Sample 14 was also a good liquid emulsion without thickening. Moreover, when the creaming was investigated about the sample 14 like the comparative example 1, the cream layer was not formed in the upper part but the favorable result was obtained.

(Example 11)
Fresh cream (oil content 47% by weight, initial particle size 3.2 μm) was temperature-controlled at 60 ° C., and then circulated for 8 minutes using a homogenizer under pressure conditions of 3 Mpa. Thereafter, the mixture was circulated for 1 minute under a pressure condition of 4 Mpa to obtain an intermediate emulsion having an intermediate particle size of 1.7 μm. The intermediate emulsion was further circulated for 1 minute using a homogenizer with a pressure condition of 5 Mpa. Thereafter, the sample 15 was obtained by sterilization treatment and cooling in the same manner as in Example 1. The final particle size was 1.5 μm. Sample 15 was also a good liquid emulsion without thickening. Moreover, when creaming was investigated about the sample 15 like the comparative example 1, the cream layer was not formed in the upper part but the favorable result was obtained.

(Comparative Example 5)
A fresh cream (47% oil content, initial particle size 3.2 μm) was temperature-controlled at 60 ° C., then tried to reduce the particle size by a single treatment, and treated once with a homogenizer at a pressure of 8 Mpa. (Sample 16). As a result, milk fat aggregated and thickened immediately after the treatment. When the particle size was measured, the final particle size was 7.9 μm larger than the initial particle size.

(Example 12)
Fresh cream (oil content 35% by weight, initial particle size 3.8 μm) was adjusted to 60 ° C. and then circulated for 10 minutes using a homogenizer with a pressure condition of 2 Mpa, and then 10 minutes each at 3 Mpa, 4 Mpa, and 5 Mpa. Circulation was performed to obtain an intermediate emulsion having an intermediate particle size of 1.0 μm. This intermediate emulsion was further circulated for 10 minutes using a homogenizer with a pressure condition of 6 Mpa. Thereafter, the sample 17 was obtained by sterilization treatment and cooling in the same manner as in Example 1. The final particle size was 0.9 μm. Sample 17 was also a good liquid emulsion without thickening. Moreover, when the creaming was investigated about the sample 17 like the comparative example 1, the cream layer was not formed in the upper part but the favorable result was obtained.

(Example 13)
Fresh cream (oil content 35% by weight, initial particle size 3.8 μm) was heated to 60 ° C., then treated with pressure conditions 2 Mpa 3 times, 3 Mpa 3 times, 4 Mpa 3 times, 5 Mpa 3 times, An intermediate emulsion having a diameter of 1.2 μm was obtained. This intermediate emulsion was further processed three times under a pressure condition of 6 Mpa. Thereafter, the sample 18 was obtained by sterilization treatment and cooling in the same manner as in Example 1. The final particle size was 0.9 μm. Sample 18 was also a good liquid emulsion without thickening. Moreover, when the creaming was investigated about the sample 18 like the comparative example 1, the cream layer was not formed in the upper layer, but the favorable result was obtained.

(Comparative Example 6)
After temperature control of fresh cream (oil content 35%, initial particle size 3.8 μm) to 60 ° C., an attempt was made to reduce the particle size by one treatment, and treatment was performed once at a pressure condition of 6 Mpa using a homogenizer ( Sample 19). As a result, milk fat aggregated and thickened immediately after the treatment. When the particle size was measured, the final particle size was 16.5 μm larger than the initial particle size.

  Tables 1 to 4 show the evaluation of the processing conditions, initial particle diameter, intermediate particle diameter, and long-term storage stability of the above Examples and Comparative Examples (Samples 1 to 19).

As can be seen from Tables 1 to 4, the oil-in-water emulsion (preliminary emulsified liquid) and fresh cream used as raw materials are repeatedly homogenized several times, and the particle size of the oil droplets is reduced stepwise. Therefore, even without adding an emulsifier, a protein molten salt, and a pH adjuster, the oil droplets do not aggregate and the emulsion does not thicken, and the oil droplets have a particle size of 5.0 μm or less. In, the particle size of fat globules can be further reduced. Therefore, according to the present invention, an oil-in-water emulsion excellent in storage stability and flavor can be produced, and the shelf life of fresh cream can be extended.

Claims (7)

  An oil-in-water type production method of an oil-in-water emulsion containing a micellar protein, having a median diameter of oil droplets of 0.3 to 5.0 μm and a fat content of 20 to 60% by weight Oil-in-water, characterized in that the median diameter of oil droplets contained in the emulsion is reduced stepwise to make the final median diameter of the oil droplets a desired particle size in the range of 0.3 to 5.0 μm A method for producing a mold emulsion.   The oil-in-water emulsion that is the raw material is homogenized multiple times to gradually reduce the median diameter of the oil droplets until the final median diameter of the oil droplets reaches the desired particle size. The method for producing an oil-in-water emulsion according to claim 1, wherein the homogenization treatment is repeated.   The method for producing an oil-in-water emulsion according to claim 2, wherein the homogenization is repeated by sequentially increasing the pressure setting until the median diameter of the oil droplets reaches a desired particle diameter.   The water-in-water emulsion according to any one of claims 1 to 3, wherein the oil-in-water emulsion as a raw material is an oil-in-water emulsion prepared by pre-emulsifying with water, containing at least oils and micelles as essential components. A method for producing an oil-type emulsion.   The oil-in-water emulsion used as a raw material is a fresh cream, The manufacturing method of the oil-in-water emulsion in any one of Claims 1-3.   The method for producing an oil-in-water emulsion according to claim 5, wherein the homogenization treatment is repeated until the final median diameter of the oil droplets is 3.0 µm or less. The method for producing an oil-in-water emulsion according to any one of claims 1 to 6, wherein an emulsifier, a protein molten salt and a pH adjuster are not added.