Oil-in-water emulsion

Abstract

To provide an oil-in-water type emulsifier with which an acid milk product is obtained, the product being stable even if heated at a high temperature in an acid state.SOLUTION: An oil-in-water type emulsifier for imparting acid resistance and heat resistance contains, in oil and fat, transesterified oil and fat from palm-based oil and fat and laurin-based oil and fat. In the oil-in-water type emulsifier, an SFC decreasing rate is 25% or more when the emulsifier is stayed for 30 minutes at 0°C from the time when the oil and fat are melted and then stayed for 60 seconds at 35°C, and an SFC is 52% or more when the emulsifier is stayed for 10 minutes at 5°C from the time of melting.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an oil-in-water emulsion and a food product containing the oil-in-water emulsion. [Background technology]

[0002] Conventionally, foods and beverages (hereinafter referred to as "sour milk products") have been proposed that are processed by adding acidic ingredients such as fruit juice, fruit, acidulants, or pH adjusters such as citric acid to milk such as cow's milk, or various dairy products such as skim milk, fresh cream, cheese, and fermented milk. Examples of such sour milk products include gelled foods such as jelly, almond tofu, and milk pudding. When producing sour milk products, a sterilization step by heating at a high temperature (for example, a temperature of around 100°C) may be required.

[0003] However, when a sour milk product containing an acidic component in addition to a dairy product is heated at a high temperature, the emulsion becomes unstable due to the influence of the acidic component in the sour milk product, resulting in emulsion breakdown. As a result, the sour milk product is prone to forming aggregates and separation. In addition, the milk proteins contained in the sour milk product are heat-sensitive and may be denatured by the above-mentioned high-temperature heating process. As described above, when a dairy product and a sour milk product containing an acidic component are heated at a high temperature, emulsion breakdown and milk protein denaturation occur.

[0004] Therefore, in recent years, a technology has been proposed in which oil-in-water emulsions in which vegetable oils are emulsified instead of dairy products such as fresh cream are used to prevent emulsion breakdown and denaturation of milk proteins when foods and beverages containing acidic ingredients are heated at high temperatures. However, when oil-in-water emulsions in which vegetable oils are emulsified are used, there is a problem that the flavor is weaker than that of foods and beverages containing dairy products. Therefore, even when oil-in-water emulsions in which vegetable oils are emulsified are used, it is necessary to add dairy products to compensate for the flavor. When oil-in-water emulsions containing dairy products are heated at high temperatures in the presence of acidic ingredients (i.e., under acidic conditions), emulsion breakdown and denaturation of milk proteins still occur in the oil-in-water emulsions. As described above, there is room for improvement in the stability of such oil-in-water emulsions against high-temperature heating under acidic conditions.

[0005] As a means for solving such problems, Patent Document 1 discloses an acid-resistant cream that prevents aggregation and solidification when used in acidic foods such as fruit jelly, mango pudding, etc. Specifically, the proposed acid-resistant cream contains a sucrose fatty acid ester with an HLB value of 14 or more, galactomannan and / or agar, and enzymatically hydrolyzed lecithin and / or polyglycerin fatty acid ester.

[0006] Patent Document 2 discloses an oil-in-water emulsified oil composition for acidic desserts that prevents aggregation, precipitation, plasticization, etc. when used in dessert foods containing acidic substances such as fruit juice. Specifically, the proposed oil-in-water emulsified oil composition for acidic desserts contains lactose and trisodium citrate. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-168427 [Patent Document 2] Japanese Patent Application Publication No. 7-255376 Summary of the Invention [Problem to be solved by the invention]

[0008] However, even in the techniques of Patent Documents 1 and 2, there is room for improvement in terms of stability when heated at high temperatures under acidic conditions (i.e., acid resistance and heat resistance).

[0009] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an oil-in-water emulsion that can give a stable sour milk product even when heated at high temperatures under acidic conditions. [Means for solving the problem]

[0010] In order to solve the above problems, the present invention provides an oil-in-water emulsion, which contains an interesterified oil of palm-based oil and lauric oil, and is characterized in that the SFC reduction rate when the oil is allowed to stand at 0°C for 30 minutes after melting and then at 35°C for 60 seconds is 25% or more, and the SFC when the oil is allowed to stand at 5°C for 10 minutes after melting is 52% or more.

[0011] The food and drink of the present invention is characterized by containing the oil-in-water emulsion described above. [Effects of the Invention]

[0012] According to the oil-in-water emulsion of the present invention, a stable sour milk product can be obtained even when heated at high temperatures under acidic conditions (i.e., in a state where an acidic component is blended). DETAILED DESCRIPTION OF THE INVENTION

[0013] The present invention will be described in detail below.

[0014] The oil-in-water emulsion of the present invention contains interesterified oils and fats made from palm-based oils and fats and lauric oils and fats.

[0015] The palm-based fats and oils used in the interesterified oils and fats that constitute the oil phase in the oil-in-water emulsion of the present invention have a content of fatty acids having 16 or more carbon atoms in all constituent fatty acids of 35% by mass or more. Examples of such palm-based fats and oils include palm oil, palm fractionated oil, and hardened oils thereof, which may be used alone or in combination of two or more. As the palm fractionated oil, hard fraction, soft fraction, mid-melting point fraction, etc. can be used. The iodine value of the palm-based fats and oils is preferably 30 to 60, more preferably 40 to 60, and even more preferably 50 to 60. Palm oil is particularly preferred as the palm-based fat and oil.

[0016] The lauric fats and oils used in the interesterified oils and oils that constitute the oil phase in the oil-in-water emulsion of the present invention have a lauric acid content of 30% by mass or more, preferably 40 to 55% by mass, and more preferably 45 to 50% by mass, of all constituent fatty acids. Examples of such lauric fats and oils include palm kernel oil, coconut oil, fractionated oils thereof, and hardened oils thereof, which may be used alone or in combination of two or more. The iodine value of the lauric fats and oils is preferably 26 or less, more preferably 10 to 20. Palm kernel oil is particularly preferred as the lauric fat and oil.

[0017] In the interesterified oils and fats obtained by interesterification of palm-based oil and lauric-based oil as described above, the ratio of the components, i.e., the ratio of palm-based oil and lauric-based oil (palm-based oil:lauric-based oil), can be considered to be in the range of 55:45 to 30:70. For example, the interesterified oils and fats made from palm-based oil and lauric-based oil contained in the oil-in-water emulsion of the present invention are preferably interesterified oils with a palm-based oil:lauric-based oil ratio of 50:50 to 30:70. The ratio of palm-based oil and lauric-based oil in the interesterified oils and fats is more preferably palm-based oil:lauric-based oil = 48:52 to 42:58.

[0018] The interesterified oils and fats can be prepared by known interesterification reactions. For example, this can be achieved by chemical interesterification using a chemical catalyst such as sodium methylate, or by enzymatic interesterification using a catalyst such as lipase. While the present invention requires the interesterified oil of palm-based oil and lauric oil as the oil phase component, any edible oil or fat can be used as the oil other than the interesterified oil contained in the oil-in-water emulsion of the present invention. For example, the oil-in-water emulsion can contain one or more of various oils and fats, such as palm oil, palm kernel oil, coconut oil, rapeseed oil, soybean oil, cottonseed oil, sunflower oil, rice bran oil, safflower oil, corn oil, olive oil, sesame oil, shea butter, monkey fat, cocoa butter, lard, beef tallow, milk fat, fractionated oils thereof, and processed oils thereof (which have been subjected to one or more of hardening and interesterification).

[0019] The content of interesterified oils and fats made from palm-based oils and fats and lauric oils in the oils and fats is not particularly limited, but is preferably 95% by mass or more, and more preferably 99% by mass or more.

[0020] The content of the transesterified oil made from palm-based oil and lauric oil in the oil-in-water emulsion is not particularly limited, but is preferably 15% by mass or more, more preferably 30% by mass or more. The upper limit of the content of the transesterified oil made from palm-based oil and lauric oil in the oil-in-water emulsion is not particularly limited, but is preferably 60% by mass or less, more preferably 40% by mass or less.

[0021] The fat or oil contained in the oil-in-water emulsion of the present invention is characterized in that the SFC reduction rate when left standing at 0°C for 30 minutes after melting and then at 35°C for 60 seconds is 25% or more, and the SFC when left standing at 5°C for 10 minutes after melting is 52% or more. The SFC reduction rate when left standing at 0°C for 30 minutes after melting and then at 35°C for 60 seconds is expressed as the percentage decrease in SFC when left standing at 35°C for 60 seconds, based on the SFC when the fat or oil is heated and completely dissolved and then left standing at 0°C for 30 minutes (SFC reduction rate (%) = 100 - (SFC when left standing at 35°C for 60 seconds / SFC when left standing at 0°C for 30 minutes after melting) × 100). The upper limit of the SFC reduction rate when the sample is left standing at 0°C for 30 minutes after melting and then at 35°C for 60 seconds is preferably 40% or less, more preferably 35% or less, and even more preferably 30% or less, from the viewpoint of preventing the occurrence of off-flavors derived from additives contained in the aqueous phase. The upper limit of the SFC when the sample is left standing at 5°C for 10 minutes after melting is preferably 60% or less, more preferably 56% or less, from the viewpoint of preventing the formation of coarse crystals of fats and oils and impairing the emulsion stability of the oil-in-water emulsion. As described in the examples below, the SFC is measured in accordance with "2.2.9-2013 Solid Fat Content (NMR Method)" of the Standard Methods for Analysis of Fats, Oils, and Related Materials (Japan Oil Chemists' Society).

[0022] In the oil-in-water emulsion of the present invention, the following are examples of components constituting the aqueous phase, separate from the fats and oils that constitute the oil phase. First, various polyol esters are considered. Among these, it is preferable to contain at least one of polysorbates and polyglycerol esters. By containing at least one of polysorbates and polyglycerol esters, it is possible to impart acid resistance and heat resistance (hereinafter also referred to as "acid and heat resistance"), as well as whiteness, to the soured milk product. The whiteness of the soured milk product depends on the number and particle size of the oil droplet particles in the oil-in-water emulsion of the present invention; the greater the number of oil droplet particles and the finer the particle size, the greater the whiteness.

[0023] Polysorbates are produced by condensing sorbitan fatty acid esters with ethylene oxide. Examples of polysorbates include polysorbate 20 (also known as polyoxyethylene sorbitan monolaurate (Tween 20)), polysorbate 60 (also known as polyoxyethylene sorbitan monostearate (Tween 60)), polysorbate 65 (also known as polyoxyethylene sorbitan tristearate (Tween 65)), and polysorbate 80 (also known as polyoxyethylene sorbitan oleate (Tween 80)). From the viewpoint of imparting acid resistance, heat resistance, and whiteness to soured dairy products, polysorbate 60 and polysorbate 80 are particularly preferred.

[0024] The content of polysorbates in the oil-in-water emulsion is not particularly limited, but is preferably 0.1% by mass or more, more preferably 0.4% by mass or more, from the viewpoint of imparting acid and heat resistance and whiteness to the sour milk product. The upper limit of the content of polysorbates in the oil-in-water emulsion is preferably 1.2% by mass or less, more preferably 0.7% by mass or less.

[0025] Examples of polyglycerol esters include polyglycerol fatty acid esters and polyglycerol condensed ricinoleic acid esters.

[0026] The content of the polyglycerol ester in the oil-in-water emulsion is not particularly limited, but from the viewpoint of imparting acid and heat resistance and whiteness to the sour dairy product, it is preferably 0.05% by mass or more, more preferably 0.10% by mass or more. The upper limit of the content of the polyglycerol ester in the oil-in-water emulsion is preferably 5% by mass or less, more preferably 4% by mass or less, and even more preferably 2% by mass or less.

[0027] Polyglycerol fatty acid esters are esters of polyglycerol and fatty acids, and examples of fatty acids include stearic acid, oleic acid, linoleic acid, linolenic acid, arachidic acid, eicosenoic acid, behenic acid, and erucic acid. Commercially available products include SY Glyster MSW-7S, SY Glyster PS-3S, SY Glyster PS-5S, SY Glyster THL-15, SY Glyster THL-44, SY Glyster THL-50, SY Glyster HB-750, and SY Glyster DDB-750, all manufactured by Sakamoto Pharmaceutical Co., Ltd.; D Series SWA-10D, SWA-15D, and SWA20D, and Ryoto Polyglycerol B-70D, all manufactured by Mitsubishi Chemical Foods Corporation; and Sunsoft Q-18S, Sunsoft Q-182S, and Sunsoft QMP-5, all manufactured by Taiyo Kagaku Co., Ltd. Polyglycerol fatty acid esters with an HLB value of 11 or higher are preferred.

[0028] Here, the HLB value can be determined by the Griffin formula (Atlas method).

[0029] The content of polyglycerol fatty acid ester in the oil-in-water emulsion is not particularly limited, but from the viewpoint of imparting acid and heat resistance and whiteness to the sour dairy product, it is preferably 0.3% by mass or more, more preferably 1% by mass or more. The upper limit of the content of polyglycerol fatty acid ester in the oil-in-water emulsion is preferably 4% by mass or less, more preferably 2% by mass or less.

[0030] The type of polyglycerol condensed ricinoleate is not particularly limited, and examples include polyglycerol condensed ricinoleate having a glycerol degree of polymerization of 2 to 10. Commercially available products include SY Glyster CR-ED (polytype), SY Glyster CR-310 (tetraglycerol degree of polymerization 4), and SY Glyster CR-500 (hexaglycerol degree of polymerization 6), all manufactured by Sakamoto Pharmaceutical Co., Ltd., and SUNFOORF 818DG (tetraglycerol degree of polymerization 4), SUNFOORF 818R (pentaglycerol degree of polymerization 5), and SUNFOORF 818SK (hexaglycerol degree of polymerization 6), all manufactured by Taiyo Kagaku Co., Ltd. Of these, polyglycerol condensed ricinoleate having a glycerol degree of polymerization of 4 to 6 is particularly preferred from the viewpoint of improving acid resistance and heat resistance.

[0031] The content of the polyglycerol condensed ricinoleate in the oil-in-water emulsion is not particularly limited, but from the viewpoint of imparting acid and heat resistance and whiteness to the sour milk product, it is preferably 0.05% by mass or more, more preferably 0.10% by mass or more. The upper limit of the content of the polyglycerol condensed ricinoleate in the oil-in-water emulsion is preferably 1% by mass or less, more preferably 0.5% by mass or less.

[0032] The oil-in-water emulsion may also contain various ingredients, such as oils and fats other than interesterified oils and fats made from palm-based oils and fats and lauric oils, emulsifiers other than polyglycerol esters, carbohydrates, milk and dairy products, proteins, pH adjusters, flavors, coloring components, and antioxidants.

[0033] The content of fats and oils in the oil-in-water emulsion is not particularly limited, but is preferably 20% by mass or more, more preferably 30% by mass or more, from the viewpoint of imparting whiteness to the soured milk product. The upper limit of the content of fats and oils in the oil-in-water emulsion is not particularly limited, but is preferably 50% by mass or less, more preferably 40% by mass or less, from the viewpoint of improving the flavor of the soured milk product.

[0034] Examples of emulsifiers other than polyglycerol esters include glycerin fatty acid esters, glycerin organic acid fatty acid esters, sorbitan fatty acid esters, sucrose fatty acid esters, propylene glycol fatty acid esters, polyoxyethylene sorbitan fatty acid esters, lecithin (soybean lecithin, egg yolk lecithin, sunflower lecithin), enzymatically hydrolyzed lecithin (soybean lysolecithin, egg yolk lysolecithin), saponin, calcium stearoyl lactylate, sodium stearoyl lactylate, modified starch (etherified carboxymethyl starch, hydroxypropyl starch, esterified starch phosphate, sodium starch octenylsuccinate, starch acetate, heat-moisture treated starch, acid-treated starch, cross-linked starch, gelatinized starch, resistant starch, etc.), sphingolipids, plant sterols, bile powder, tomato glycolipids, etc. These may be used alone or in combination of two or more.

[0035] Carbohydrates include monosaccharides (glucose, fructose, galactose, mannose, etc.), disaccharides (lactose (milk sugar), sucrose, maltose, trehalose, etc.), and oligosaccharides such as isomaltooligosaccharides (isomaltose, isomaltotriose, panose), fructooligosaccharides, galactooligosaccharides (4'-galactosyllactose), xylooligosaccharides, beet oligosaccharides (raffinose), soybean oligosaccharides (raffinose, stachyose), and lactoferrin oligosaccharides (lactosucrose). Sugars; Dextrins (dextrin, maltodextrin, isomaltodextrin (branched maltodextrin), starch syrup, powdered syrup, cyclodextrin, branched cyclodextrin, roasted dextrin, polymeric dextrin, indigestible dextrin), inulins (inulin, inulin hydrolyzate, agave inulin), thickening polysaccharides (LM pectin, HM pectin, pullulan, guar gum, guar gum hydrolyzate, xanthan gum, gum arabic, gum ghatti, native gellan gum, dehydrated Examples of suitable sugars include acylated gellan gum, locust bean gum, tara gum, galactomannan, glucomannan, konjac mannan, curdlan, carrageenan, karaya gum, cassia gum, tamarind seed gum, tragacanth gum, fenugreek gum, psyllium seed gum, succinoglycan, rhamsan gum, alginic acid, sodium alginate, PGA (propylene glycol alginate), soybean polysaccharides, methylcellulose, carboxymethylcellulose, hydroxypropyl cellulose, hydroxypropylmethylcellulose, agar, gelatin, fucoidan, porphyran, laminaran, starch, resistant starch, isomaltulose, polydextrose, indigestible glucan, and arabinogalactan; and sugar alcohols such as erythritol, sorbitol, xylitol, maltitol, lactitol, reduced isomaltulose, and mannitol. From the viewpoint of improving the flavor of the food and beverage of the present invention, isomaltooligosaccharide is particularly preferred. These may be used alone or in combination of two or more.

[0036] Examples of milk include cow's milk. Examples of dairy products include skim milk, fresh cream, cheese (natural cheese, processed cheese, etc.), fermented milk, concentrated milk, concentrated skim milk, unsweetened condensed milk, sweetened condensed milk, unsweetened condensed skim milk, sweetened condensed skim milk, milk proteins (acid casein, rennet casein, sodium caseinate, potassium caseinate, whey protein, and their enzymatic hydrolyzates such as milk peptides, milk protein concentrate, cream powder, total milk protein, whole milk powder, skim milk powder, whey powder, and buttermilk powder). These may be used alone or in combination of two or more. Of these, from the viewpoint of improving acid resistance and heat resistance, whey proteins having a whey content of 50% by mass or more are preferred, and whey proteins having a whey content of 70% by mass or more are particularly preferred.

[0037] Examples of proteins include milk protein, bean-derived proteins (soy protein, soy protein isolate, pea protein, fava bean protein, mung bean protein, kidney bean protein, lentil (lentil) protein, chickpea protein, lupin bean protein, peanut protein, cowpea protein), seed-derived proteins (proteins derived from sesame, canola, coconut, olive, sunflower, peanut, beet, cotton, almond, etc.), grain-derived proteins (proteins derived from corn, buckwheat, wheat, oats, rice, etc.), collagen, collagen peptides, gelatin, etc. These may be used alone or in combination of two or more.

[0038] Examples of pH adjusters include inorganic salts such as phosphates, metaphosphates, polyphosphates, and pyrophosphates, organic acid salts such as citrates and tartrates, and carbonates such as sodium carbonate. These may be used alone or in combination of two or more. Of these, sodium carbonate is particularly preferred from the viewpoint of improving acid resistance and heat resistance.

[0039] The oil-in-water emulsion of the present invention can be produced, for example, by the following procedure.

[0040] The various ingredients, such as fats and oils, emulsifiers, carbohydrates, dairy products, pH adjusters, and water, are mixed and emulsified. A homomixer or the like can be used for emulsification. Typically, lipophilic emulsifiers are added to the oil phase, and hydrophilic emulsifiers are added to the aqueous phase. Hydrophilic carbohydrates, dairy products, pH adjusters, etc. are dissolved in water before use. Emulsification can be carried out by heating the oil phase to a temperature at which the blended fats and oils are completely dissolved, and heating the aqueous phase to a temperature at which the oil phase does not drop in temperature after mixing, and then mixing the oil phase with the aqueous phase, at a temperature of, for example, 60 to 70°C.

[0041] After emulsification, homogenization is carried out. Homogenization can be carried out using a high-pressure homogenizer by appropriately setting conditions such as pressure that are conventionally used in the production of oil-in-water emulsions. The median diameter of the oil droplets can be adjusted during this homogenization process. Furthermore, sterilization or pasteurization can be carried out before or after homogenization. The median diameter after homogenization is preferably 0.8 to 1.6 μm, and more preferably 1.0 to 1.3 μm.

[0042] The homogenized emulsion is then cooled to obtain the oil-in-water emulsion of the present invention. Cooling is preferably carried out using equipment capable of cooling to the desired temperature in a short period of time, such as a plate heat exchanger or a tubular heat exchanger. It is preferable to use such equipment to cool to a temperature range of 1 to 7°C in a short period of time. After cooling, the emulsion is stirred under refrigeration, and on an industrial scale, it is left to stand in a tank at the cooled temperature for, for example, 1 to 2 days to stabilize (age). It is then filled into a product.

[0043] The oil-in-water emulsion of the present invention is characterized by its acid resistance and heat resistance. Regarding acid resistance and heat resistance, a general standard is that the emulsion is stable and no separation or aggregation is observed even when sterilized at normal pressure (below 100°C) at a pH of less than 4.6. The oil-in-water emulsion of the present invention has excellent acid resistance and heat resistance in light of these general standards.

[0044] Foods and beverages containing the oil-in-water emulsion of the present invention include various acidic dairy products containing an acidic component and a dairy product. Typical examples include gelled foods and beverages such as jelly, almond tofu, and milk pudding. In the present invention, the oil-in-water emulsion has acid resistance and heat resistance, which can impart acid resistance and heat resistance to the acidic dairy product containing the oil-in-water emulsion.

[0045] The amount of oil-in-water emulsion added to food or drink is not particularly limited, but is preferably 1 to 10% by mass, more preferably 2 to 8% by mass.

[0046] In the case of foods and beverages containing the oil-in-water emulsion of the present invention, particularly gelled foods, it is preferable to contain hydroxypropylated phosphate-crosslinked starch from the viewpoint of imparting acid resistance and heat resistance and whiteness. The content of hydroxypropylated phosphate-crosslinked starch in the gelled food is not particularly limited, but is preferably 0.01 to 1 mass%, more preferably 0.05 to 0.5 mass%. The content of hydroxypropylated phosphate-crosslinked starch relative to the oil-in-water emulsion is not particularly limited, but is preferably 0.5 to 5 mass%, more preferably 1 to 3 mass%. Furthermore, in addition to the polysorbates contained in the oil-in-water emulsion of the present invention, an emulsifier may be added directly to the jelly, and in particular, the addition of polysorbates can further impart acid resistance and heat resistance. [Example]

[0047] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples.

[0048] <Preparation of interesterified oils> The transesterified oils 1 to 5 were prepared by the following method. Palm kernel oil and palm oil were mixed at the mass ratios shown in Table 1 and heated to 110°C. After sufficient dehydration, 0.08% by mass of sodium methylate as a chemical catalyst was added to the amount of oil, and the transesterification reaction was carried out with stirring at 100°C for 0.5 hours under reduced pressure. After the transesterification reaction, it was washed with water to remove the catalyst, decolorized using activated clay, and further deodorized to obtain the transesterified oil.

[0049]

Table 1

[0050]

Table 2

[0051]

Table 3

[0052]

Table 4

[0053] <Preparation of oil-in-water emulsion> The aqueous and oil phases were heated to 65°C, the oil phase was added to the aqueous phase, and the mixture was emulsified by stirring. The mixture was then homogenized using a high-pressure homogenizer. The mixture was then rapidly cooled to 1-5°C and aged for 10 hours in a refrigerator while stirring to obtain an oil-in-water emulsion.

[0054] <Making jelly> Jellies containing the following acidic component (citric acid) were prepared using the various oil-in-water emulsions in Tables 2 and 3 in formulation 1 shown in Table 5, and using the various oil-in-water emulsions in Table 4 in formulation 2 shown in Table 5. Examples 18, 19, and 20 in Table 4 show the differences between formulations 1 and 2, which correspond to Examples 4, 12, and 16, respectively. 1. Gelling agent, hydroxypropylated phosphate cross-linked starch, and granulated sugar were added to 20°C water and dispersed, and the temperature was raised. 2. The product was heated and held at 85°C for 15 minutes. 3. While keeping the temperature at 60°C, the oil-in-water emulsion of the present invention and fermented milk were added. 4. Citric acid was added to adjust the pH to 4. 5. Filled into containers and sterilized at 90°C for 30 minutes (i.e., heated at high temperature under acidic conditions). 6. Cooled in running water at 20°C for 15 minutes 7. Chill in the refrigerator overnight

[0055] [Table 5]

[0056] The resulting jelly containing the oil-in-water emulsion was evaluated as follows.

[0057] [Acid resistance (coagulation)] The surface condition of the jelly was visually evaluated according to the following criteria, with a score of 3 or higher being considered to have solved the problem. 5: No agglomerates are visible and the appearance is very good 4: Almost no agglomerates are visible, and the appearance is good 3: Only a few aggregates, and the appearance is generally good 2: Agglomerates are observed and the appearance is slightly poor 1: Many clearly visible aggregates, poor appearance 0: The surface is covered with agglomerates and the appearance is very poor

[0058] [Acid and heat resistance (chatter)] The texture of the jelly was visually evaluated according to the following criteria, with a score of 3 or higher being considered to have solved the problem. 7: The appearance is very good and the surface is very uniform, even when cut, including the inner layer. 6: Very uniform and good appearance 5: Uniform and good appearance 4: Relatively uniform and generally good appearance 3: Almost no hazy spots are visible and the appearance is fine 2: Uneven, hazy, and poor appearance 1: Uneven, coarse, and fuzzy, with a very poor appearance 0: Separated

[0059] [Whiteness] The color tone (whiteness) of the jelly was visually evaluated according to the following criteria, with a score of 3 or higher being considered to have solved the problem. 7: No matter where you cut it, including the inner layer, it is cloudy and bright, and the appearance is very good. 6: Very cloudy, bright and has a very good appearance 5: Dark cloudiness and good appearance 4: Cloudy and good appearance 3: Relatively white, no problem with appearance 2: Light whiteness and poor appearance 1: The white is pale, dark and looks bad 0: Not enough whiteness

[0060] <Evaluation by jelly tasting> A panel of 13 people tasted the jelly containing the oil-in-water emulsion and evaluated the balance of milk flavor, sourness, thickness (richness), and melt-in-the-mouth texture according to the following criteria. The sensory evaluation below was carried out after the selection of the panel shown below and discussion among the panel. A five-taste (sweet, sour, salty, bitter, and umami) discrimination test, a taste concentration difference discrimination test, a food taste discrimination test, and a standard smell test were conducted, and 13 panelists (six men and seven women in their 20s to 40s) who were deemed suitable for each test were selected. Next, before conducting the sensory evaluation, the entire panel discussed the matter in advance to ensure that each panel member had a common understanding of the characteristics of each evaluation item. Furthermore, to eliminate panel bias in the sensory evaluation and increase the accuracy of the evaluation, the test lot numbers and contents of the samples were not disclosed to the panel members, and they were presented randomly. A score of 3 or higher was considered to have resolved the issue.

[0061] [Flavor] 6: Of the 13 panelists, more than 12 people rated the product as having a good thickness (richness) and melt-in-the-mouth texture, with an overall good balance. 5: Of the 13 panelists, between 10 and 11 people rated the product as having good thickness (richness) and melt-in-the-mouth texture, with a good overall balance. 4: Of the 13 panelists, between 8 and 9 people rated the product as having good thickness (richness) and melt-in-the-mouth texture, with a good overall balance. 3: Of the 13 panelists, 6 to 7 people rated the product as having good thickness (richness) and melt-in-the-mouth texture, with a good overall balance. 2: Of the 13 panelists, between 4 and 5 people rated the product as having good thickness (richness) and melt-in-the-mouth texture, with an overall good balance. 1: Of the 13 panelists, 2 to 3 people rated the product as having good thickness (richness) and melt-in-the-mouth texture, with a good overall balance. 0: Of the 13 panelists, 1 or less evaluated that both the thickness (richness) and melt-in-the-mouth texture were good, and that the overall balance was good.

[0062] <Result> In Comparative Examples 1 to 4, the SFC reduction rate when left standing at 0°C for 30 minutes after melting and then at 35°C for 60 seconds was not 25% or more, and the SFC when left standing at 5°C for 10 minutes after melting was not 52% or more, and therefore it can be seen that the evaluation of acid resistance and heat resistance (aggregation and roughness) was low.

[0063] In contrast, in Examples 1 to 20, the SFC loss of the oil in the oil-in-water emulsion was 25% or more when left at 0°C for 30 minutes after melting and then at 35°C for 60 seconds, and the SFC was 52% or more when left at 5°C for 10 minutes after melting, demonstrating high evaluations of acid and heat resistance (aggregation and roughness). In other words, in Examples 1 to 20, by incorporating the oil-in-water emulsion into jelly, it was possible to obtain a jelly that was free from aggregation and roughness, despite the incorporation of dairy products (fermented milk in the jelly and whey in the aqueous phase of the oil-in-water emulsion) and an acidic component (citric acid). As described above, in Examples 1 to 20, sour dairy products (jelly) that were stable even when heated at high temperatures under acidic conditions were obtained.

[0064] The results in Table 2 show that the use of at least one of polysorbates and polyglycerol fatty acid esters significantly improves the acid- and heat-resistance and whiteness of the jelly. Furthermore, it is clear that the acid- and heat-resistance and whiteness of the jelly are further improved when the amount of polysorbates added is 0.4 to 0.7% by mass or the amount of polyglycerol fatty acid ester added is 1.0 to 2.0% by mass.

[0065] From the results in Tables 2 and 4, it can be seen that the use of hydroxypropylated phosphate cross-linked starch significantly improves the acid resistance and heat resistance (roughness) and whiteness of the jelly.

Claims

1. An oil-in-water emulsion for imparting acid resistance and heat resistance, Contains interesterified palm oil and lauric oil, The interesterified oil is an interesterified oil having a palm oil:palm kernel oil ratio of 55:45 to 30:70, An oil-in-water emulsion, wherein the SFC reduction rate when the oil contained in the emulsion is allowed to stand at 0°C for 30 minutes from the time of melting and then at 35°C for 60 seconds is 25% or more, and the SFC when the emulsion is allowed to stand at 5°C for 10 minutes from the time of melting is 52% or more.

2. 2. The oil-in-water emulsion according to claim 1, which contains at least one of polysorbates and polyglycerol esters.

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