Oil-in-water emulsion and foamable oil-in-water emulsion

Abstract

The purpose of this invention is to provide an oil-in-water emulsion and a foamable oil-in-water emulsion with minimized thickening and solidification during refrigerated storage.　This oil-in-water emulsion contains oil / fat having a weight ratio S2Po / S2M of 0.03 or more. S2Po is a triglyceride in which two Ss and one Po are bonded, and S2M is a triglyceride in which two Ss and one M are bonded. Here, S denotes a 16-22 C saturated fatty acid, M denotes a 16-22 C monovalent unsaturated fatty acid, and Po denotes a palmitoleic acid (C16: 1 (n-7)).

Description

Oil-in-water emulsions and foamable oil-in-water emulsions

[0001] RELATED ART This application claims the benefit of priority from Application No. 2024-120288, filed with the Japan Patent Office on July 25, 2024. The priority application is hereby incorporated by reference in its entirety.

[0002] The present invention relates to oil-in-water emulsions and foamable oil-in-water emulsions.

[0003] In oil-in-water emulsions and foamable oil-in-water emulsions, such as cooking cream and whipped cream, milk fat and / or vegetable oil are generally used.

[0004] Oil-in-water emulsions and foamable oil-in-water emulsions containing only milk fat as the fat component have the advantage of possessing a pleasant flavor specific to dairy ingredients. However, they also have the following known drawbacks. First, storage at temperatures outside the optimal refrigeration range or impact during transportation can cause aggregation and coalescence of dispersed oil droplets, resulting in increased product viscosity, decreased fluidity (blotting), and oil-water separation. Second, whipped cream produced using such oil-in-water emulsions may have insufficient crystals at low temperatures and exhibit horizontal melting behavior in which some of the fat remains undissolved even at medium to high temperatures, resulting in insufficient meltability in the mouth and shape retention. To overcome these drawbacks, various vegetable oils and fats are used.

[0005] For example, foamable oil-in-water emulsions using lauric oils such as coconut oil and palm kernel oil are widely used because they melt smoothly in the mouth and have high emulsion stability. However, whipped creams produced using emulsions containing large amounts of lauric oils tend to harden over time (chunkiness) and may also have poor texture and squeezing properties.

[0006] Palm oil, particularly palm mid-melting point oil, is sometimes used as another vegetable oil. Palm oil is inexpensive and has a stable supply. Furthermore, 1,3-dipalmitoyl-2-oleoyl triacylglycerol (hereinafter sometimes referred to as POP, where P stands for palmitic acid and O stands for oleic acid), which is abundant in palm oil, is hard at low temperatures and melts quickly at around body temperature. For these reasons, palm oil is often used to produce whipped cream that combines a smooth melt-in-the-mouth texture with good shape retention. However, palm oil has the issue of leaving room for improvement in emulsion stability compared to lauric oil.

[0007] Various methods have been proposed to solve these problems with oil-in-water emulsions and foamable oil-in-water emulsions that use palm-based fats and oils, particularly palm mid-melting point fraction, as the oil phase.

[0008] As a method for improving emulsion stability, Non-Patent Documents 1 and 2 disclose a technique for improving emulsion stability by adding a sucrose fatty acid ester or a polyglycerol fatty acid ester, the constituent fatty acids of which are palmitic acid and stearic acid, to palm mid-melting point fraction. However, the addition of these emulsifiers can deteriorate the flavor, and further, the improvement in emulsion stability by the emulsifiers can in turn cause a decrease in foamability, so that the addition of large amounts is sometimes undesirable.

[0009] Patent Document 1 discloses a foamable oil-in-water emulsion that is obtained by adjusting the PPO content in PO to a predetermined ratio through a random transesterification reaction using lipase on raw materials that mainly consist of palm-based oils and lauric oils, thereby imparting excellent emulsion stability, foaming properties, and shape retention after foaming.

[0010] Patent Document 2 discloses that by blending a very small amount of disaturated monolinoleic acid triglyceride (S2L triglyceride) with palm mid-melting point fraction, an excellent foaming oil-in-water emulsion can be obtained that has a fresh texture and combines emulsion stability and foaming properties.

[0011] International Publication No. 2013 / 125385 International Publication No. 2006 / 112138

[0012] Arima, S., Ueji, T., Ueno, S., Ogawa, A., & Sato, K. (2007). Retardation of crystallization-induced destabilization of PMF-in-water emulsion with emulsifier additives. Colloids and Surfaces B: Biointerfaces, 55 (1), 98-106. Awad, T., & Sato, K. (2001). Effects of hydrophobic emulsifier additives on crystallization behavior of palm mid fraction in oil-in-water emulsion. Journal of the American Oil Chemists' Society, 78, 837-842.

[0013] Various methods have been proposed for improving emulsion stability in oil-in-water emulsions and foamable oil-in-water emulsions based on S2O, a triglyceride consisting of two saturated fatty acids (S) and one oleic acid (O), which is abundant in palm-based fats and oils, particularly the palm mid-melting point fraction, and each has been found to be highly effective, as in Patent Documents 1 and 2. However, Patent Documents 1 and 2 do not mention thickening and solidification during refrigerated storage, and no satisfactory solution has been presented. An object of the present invention is to suppress thickening and solidification during refrigerated storage in oil-in-water emulsions and foamable oil-in-water emulsions.

[0014] As a result of extensive research, the present inventors have found that thickening and solidification during refrigerated storage can be suppressed by incorporating into an oil-in-water emulsion an oil having a weight ratio of 0.03 or more between a triglyceride (S2Po) composed of two saturated fatty acids (S) and one palmitoleic acid (C16:1(n-7), hereinafter sometimes referred to as "Po") and a triglyceride (S2M) composed of two saturated fatty acids (S) and one monounsaturated fatty acid (M) having 16 to 22 carbon atoms (S2Po / S2M). Furthermore, they have found that a foamable oil-in-water emulsion using this oil-in-water emulsion has good foaming properties, and that whipped cream with excellent melt-in-the-mouth properties, cooling sensation, and shape retention can be produced by foaming this foamable oil-in-water emulsion, thereby completing the present invention.

[0015] That is, the present invention includes the following: [1] An oil-in-water emulsion containing an oil having an S2Po / S2M weight ratio of 0.03 or more. S2Po is a triglyceride in which two S's and one Po are bonded, and S2M is a triglyceride in which two S's and one M are bonded. Here, S means a saturated fatty acid having 16 to 22 carbon atoms, Po means palmitoleic acid (C16:1(n-7)), and M means a monounsaturated fatty acid having 16 to 22 carbon atoms. [2] The oil-in-water emulsion according to [1], in which the Po / M weight ratio in the oil is 0.03 or more. Here, Po means palmitoleic acid (C16:1(n-7)), and M means a monounsaturated fatty acid having 16 to 22 carbon atoms. [3] The oil-in-water emulsion according to [1] or [2], in which the Po content in the oil is 0.3% by weight or more. [4] The oil-in-water emulsion according to [1] or [2], wherein the weight ratio of P2Po / S2M in the oil or fat is 0.03 or more. P2Po is a triglyceride in which two P's and one Po are bonded together. Here, P means palmitic acid. [5] The oil-in-water emulsion according to [1] or [2], wherein the weight ratio of PPoSt / S2M in the oil or fat is 0.01 or more. PPoSt is a triglyceride in which one P, one Po, and one St are bonded together. Here, P means palmitic acid, and St means stearic acid. [6] The oil-in-water emulsion according to [1] or [2], wherein the weight ratio of St2Po / S2M in the oil or fat is 0.02 or more. St2Po is a triglyceride in which two St's and one Po are bonded together. Here, St means stearic acid. [7] The oil-in-water emulsion according to [3], wherein the weight ratio of P2Po / S2M in the oil is 0.03 or more. P2Po is a triglyceride in which two P's and one Po are bonded, where P means palmitic acid. [8] The oil-in-water emulsion according to [3], wherein the weight ratio of PPoSt / S2M in the oil is 0.01 or more. PPoSt is a triglyceride in which one P, one Po, and one St are bonded, where P means palmitic acid, and St means stearic acid. [9] The oil-in-water emulsion according to [3], wherein the weight ratio of St2Po / S2M in the oil is 0.02 or more. St2Po is a triglyceride in which two St's and one Po are bonded, where St means stearic acid.

[10] The oil-in-water emulsion according to [1] or [2], which is a foamable oil-in-water emulsion.

[11] The oil-in-water emulsion according to [3], which is a foamable oil-in-water emulsion.

[12] The oil-in-water emulsion according to [4], which is a foamable oil-in-water emulsion.

[13] The oil-in-water emulsion according to [5], which is a foamable oil-in-water emulsion.

[14] The oil-in-water emulsion according to [6], which is a foamable oil-in-water emulsion.

[15] The oil-in-water emulsion according to [7], which is a foamable oil-in-water emulsion.

[16] The oil-in-water emulsion according to [8], which is a foamable oil-in-water emulsion.

[17] The oil-in-water emulsion according to [9], which is a foamable oil-in-water emulsion.

[18] Whipped cream obtained by whipping the foamable oil-in-water emulsion according to

[10] .

[19] Whipped cream obtained by whipping the foamable oil-in-water emulsion according to

[11] .

[20] Whipped cream obtained by whipping the foamable oil-in-water emulsion according to

[12] .

[21] Whipped cream obtained by whipping the foamable oil-in-water emulsion according to

[13] .

[22] Whipped cream obtained by whipping the foamable oil-in-water emulsion according to

[14] .

[23] Whipped cream obtained by whipping the foamable oil-in-water emulsion according to

[15] .

[24] Whipped cream obtained by whipping the foamable oil-in-water emulsion according to

[16] .

[25] Whipped cream obtained by whipping the foamable oil-in-water emulsion according to

[17] .

[26] A method for producing an oil-in-water emulsion or a foamable oil-in-water emulsion, comprising: containing an oil or fat having a weight ratio of S2Po / S2M of 0.03 or more in an oil phase; mixing the oil or fat with an aqueous phase containing at least water; and emulsifying the oil-in-water emulsion. S2Po is a triglyceride in which two S's and one Po are bonded, and S2M is a triglyceride in which two S's and one M are bonded. Here, S means a saturated fatty acid having 16 to 22 carbon atoms, Po means palmitoleic acid (C16:1(n-7)), and M means a monounsaturated fatty acid having 16 to 22 carbon atoms.

[27] A method for producing an oil-in-water emulsion or a foamable oil-in-water emulsion according to

[26] , wherein the weight ratio of Po / M in the oil or fat is 0.03 or more.

[28] A method for producing an oil-in-water emulsion or a foamable oil-in-water emulsion according to

[26] or

[27] , wherein the Po content in the oil or fat is 0.3 wt% or more.

[29] A method for producing an oil-in-water emulsion or a foamable oil-in-water emulsion according to

[26] or

[27] , wherein the weight ratio of P2Po / S2M in the oil or fat is 0.03 or more. P2Po is a triglyceride in which two P's and one Po are bonded together. Here, P means palmitic acid.

[30] A method for producing an oil-in-water emulsion or a foamable oil-in-water emulsion according to

[26] or

[27] , wherein the weight ratio of PPoSt / S2M in the oil or fat is 0.01 or more. PPoSt is a triglyceride in which one P, one Po, and one St are bonded together. Here, P means palmitic acid, and St means stearic acid.

[31] A method for producing an oil-in-water emulsion or a foamable oil-in-water emulsion according to

[26] or

[27] , wherein the weight ratio of St2Po / S2M in the oil or fat is 0.02 or more. St2Po is a triglyceride in which two St and one Po are bonded together. Here, St means stearic acid, and Po means palmitoleic acid (C16:1(n-7)).

[32] A method for producing an oil-in-water emulsion or a foamable oil-in-water emulsion according to

[28] , wherein the weight ratio of P2Po / S2M in the oil or fat is 0.03 or more. P2Po is a triglyceride in which two P and one Po are bonded together. Here, P means palmitic acid.

[33] A method for producing an oil-in-water emulsion or a foamable oil-in-water emulsion according to

[28] , wherein the weight ratio of PPoSt / S2M in the oil is 0.01 or more. PPoSt is a triglyceride having one P, one Po, and one St bonded together. Here, P means palmitic acid, and St means stearic acid.

[34] A method for producing an oil-in-water emulsion or a foamable oil-in-water emulsion according to

[28] , wherein the weight ratio of St2Po / S2M in the oil is 0.02 or more. St2Po is a triglyceride having two Sts and one Po bonded together. Here, St means stearic acid.

[35] A method for suppressing thickening and solidification during refrigerated storage by including an oil having a weight ratio of S2Po / S2M of 0.03 or more in an oil-in-water emulsion or a foamable oil-in-water emulsion. S2Po is a triglyceride with two S's and one Po bonded together, and S2M is a triglyceride with two S's and one M bonded together, where S means a saturated fatty acid with 16 to 22 carbon atoms, Po means palmitoleic acid (C16:1(n-7)), and M means a monounsaturated fatty acid with 16 to 22 carbon atoms.

[0016] The present invention provides an oil-in-water emulsion that is inhibited from thickening or solidifying during refrigerated storage. Furthermore, a foamable oil-in-water emulsion using the oil-in-water emulsion has good foaming properties. Furthermore, whipped cream obtained by whipping the foamable oil-in-water emulsion has excellent melt-in-the-mouth properties, a cooling sensation, and good shape retention.

[0017] The present invention will be specifically described below.

[0018] ■ Oil-in-water emulsion and foamable oil-in-water emulsion The present invention provides an oil-in-water emulsion and a foamable oil-in-water emulsion. The oil-in-water emulsion of the present invention refers to an oil-in-water emulsion prepared by combining an emulsifier with a base ingredient such as fat or oil, water, or the like. The base ingredient may also contain protein. The oil-in-water emulsion can be used as a cooking cream or the like without being whipped, or can be used as a foamable oil-in-water emulsion by being whipped. The foamable oil-in-water emulsion is sometimes called cream for whipping cream. The foamable oil-in-water emulsion can be whipped using a whipping device or a dedicated mixer to be used as whipped cream. Whipped cream is also sometimes called whipped cream.

[0019] The oils and fats used in the oil-in-water emulsion and foamable oil-in-water emulsion of the present invention are not particularly limited, as long as they include an oil and fat having an S2Po / S2M weight ratio of 0.03 or more. In this specification, S2Po refers to a triglyceride in which two S's and one Po are bonded, and S2M refers to a triglyceride in which two S's and one M are bonded. Furthermore, in this specification, S refers to a saturated fatty acid having 16 to 22 carbon atoms, Po refers to palmitoleic acid (C16:1(n-7)), and M refers to a monounsaturated fatty acid having 16 to 22 carbon atoms. More specifically, in one embodiment, examples of oils and fats containing Po include various natural animal and plant oils such as marine oils and vegetable oils, and oils and fats obtained from microorganisms and algae. In addition, fats and oils obtained from plants, microorganisms, and algae whose fatty acid composition has been modified to include Po using conventional breeding techniques utilizing natural and artificial mutants, or new breeding techniques such as genetic engineering and genome editing, can also be used. The blending ratio of fats and oils having an S2Po / S2M weight ratio of 0.03 or more in the oil-in-water emulsion and foamable oil-in-water emulsion of the present invention is preferably 10 to 60% by weight. This blending ratio is more preferably 12% by weight or more, even more preferably 14% by weight or more, 15% by weight or more, 16% by weight or more, 18% by weight or more, and most preferably 20% by weight or more. Meanwhile, the blending ratio of the fats and oils is more preferably 55% by weight or less, even more preferably 52% by weight or less, 50% by weight or less, 48% by weight or less, 45% by weight or less, 43% by weight or less, and most preferably 40% by weight or less. By using this range appropriately, the effects of the present invention can be more effectively achieved.

[0020] The S2Po / S2M weight ratio of the oil or fat having an S2Po / S2M weight ratio of 0.03 or more contained in the oil-in-water emulsion and foamable oil-in-water emulsion of the present invention is preferably 0.04 or more, more preferably 0.05 or more, and even more preferably 0.06 or more. On the other hand, the S2Po / S2M weight ratio is preferably 0.5 or less, more preferably 0.4 or less. By ensuring that this range is appropriate, the effects of the present invention can be achieved.

[0021] The oils and fats contained in the oil-in-water emulsion and foamable oil-in-water emulsion of the present invention, having a S2Po / S2M weight ratio of 0.03 or more, preferably have a Po / M (palmitoleic acid / monounsaturated fatty acid) weight ratio of 0.03 or more in their fatty acid composition, more preferably 0.03 or more, more preferably 0.04 or more, and even more preferably 0.05 or more. Meanwhile, the Po / M weight ratio is preferably 0.5 or less, more preferably 0.4 or less. By ensuring that this range is appropriate, the effects of the present invention can be more effectively achieved.

[0022] The oil or fat having an S2Po / S2M weight ratio of 0.03 or more contained in the oil-in-water emulsion and foamable oil-in-water emulsion of the present invention preferably has a Po (palmitoleic acid) content of 0.3% by weight or more in the constituent fatty acid composition, more preferably 0.4% by weight or more, even more preferably 0.5% by weight or more, 0.6% by weight or more, 0.7% by weight or more, and most preferably 0.8% by weight or more. By having this range appropriate, the effects of the present invention can be more effectively achieved.

[0023] The S2Po content of the oil or fat having an S2Po / S2M weight ratio of 0.03 or more contained in the oil-in-water emulsion and foamable oil-in-water emulsion of the present invention is preferably 0.1% by weight or more, more preferably 0.3% by weight or more, even more preferably 0.5% by weight or more, 1% by weight or more, 1.5% by weight or more, 2% by weight or more, and most preferably 2.5% by weight or more. On the other hand, the content is preferably 60% by weight or less, more preferably 55% by weight or less, even more preferably 50% by weight or less, 45% by weight or less, 40% by weight or less, 35% by weight or less, and most preferably 32% by weight or less. By ensuring that this range is appropriate, the effects of the present invention can be more effectively achieved.

[0024] In one embodiment, the oil or fat contained in the oil-in-water emulsion and foamable oil-in-water emulsion of the present invention, having an S2Po / S2M weight ratio of 0.03 or more, preferably has a P2Po / S2M weight ratio of 0.03 or more, more preferably 0.04 or more, even more preferably 0.05 or more, and most preferably 0.06 or more. Meanwhile, the P2Po / S2M weight ratio is preferably 0.5 or less, more preferably 0.4 or less. By ensuring that this range is appropriate, the effects of the present invention can be more effectively achieved. In this specification, P2Po refers to a triglyceride in which two P's and one Po are bonded. Furthermore, in this specification, P refers to palmitic acid.

[0025] In one embodiment, the P2Po content of the oil or fat having an S2Po / S2M weight ratio of 0.03 or more contained in the oil-in-water emulsion and foamable oil-in-water emulsion of the present invention is preferably 0.1% by weight or more, more preferably 0.3% by weight or more, even more preferably 0.5% by weight or more, 1% by weight or more, 1.5% by weight or more, and most preferably 2% by weight or more. On the other hand, the P2Po content is preferably 60% by weight or less, more preferably 55% by weight or less, even more preferably 50% by weight or less, 45% by weight or less, 40% by weight or less, 35% by weight or less, and most preferably 32% by weight or less. By ensuring that this range is appropriate, the effects of the present invention can be more effectively achieved.

[0026] In one embodiment, the PPoSt / S2M weight ratio of the oil or fat contained in the oil-in-water emulsion and foamable oil-in-water emulsion of the present invention, which has an S2Po / S2M weight ratio of 0.03 or more, is preferably 0.01 or more, more preferably 0.02 or more. Meanwhile, the PPoSt / S2M weight ratio is preferably 0.1 or less, more preferably 0.08 or less. By ensuring that this range is appropriate, the effects of the present invention can be more effectively achieved. In this specification, PPoSt refers to a triglyceride in which one P, one Po, and one St are bonded. Furthermore, in this specification, St refers to stearic acid.

[0027] In one embodiment, the PPoSt content of the oil or fat having an S2Po / S2M weight ratio of 0.03 or more contained in the oil-in-water emulsion and foamable oil-in-water emulsion of the present invention is preferably 0.05% by weight or more, more preferably 0.1% by weight or more. On the other hand, the PPoSt content is preferably 20% by weight or less, more preferably 15% by weight or less, 10% by weight or less, 8% by weight or less, and most preferably 6% by weight or less. By ensuring that this range is appropriate, the effects of the present invention can be more effectively achieved.

[0028] In one embodiment, the oil or fat contained in the oil-in-water emulsion and foamable oil-in-water emulsion of the present invention, having a weight ratio of S2Po / S2M of 0.03 or more, preferably has a weight ratio of St2Po / S2M of 0.02 or more, more preferably 0.03 or more. On the other hand, the weight ratio of St2Po / S2M is preferably 0.2 or less, more preferably 0.1 or less. By ensuring that this range is appropriate, the effects of the present invention can be more effectively achieved. In this specification, St2Po means a triglyceride in which two St and one Po are bonded.

[0029] In one embodiment, the St2Po content of the oil or fat having an S2Po / S2M weight ratio of 0.03 or more contained in the oil-in-water emulsion and foamable oil-in-water emulsion of the present invention is preferably 0.05% by weight or more, more preferably 0.1% by weight or more. On the other hand, the St2Po content is preferably 20% by weight or less, more preferably 15% by weight or less, 10% by weight or less, 8% by weight or less, and most preferably 6% by weight or less. By ensuring that this range is appropriate, the effects of the present invention can be more effectively achieved.

[0030] The S2M content of the oil or fat having an S2Po / S2M weight ratio of 0.03 or more contained in the oil-in-water emulsion and foamable oil-in-water emulsion of the present invention is preferably 25% by weight or more, more preferably 30% by weight or more, even more preferably 35% by weight or more, and most preferably 40% by weight or more. On the other hand, the S2M content is preferably 90% by weight or less. If this content is appropriate, more appropriate foaming properties and shape retention can be obtained, particularly in the foamable oil-in-water emulsion.

[0031] The S3 (triglyceride in which three saturated fatty acids (S) having 16 to 22 carbon atoms are bonded) content of the oil or fat having an S2Po / S2M weight ratio of 0.03 or more contained in the oil-in-water emulsion and foamable oil-in-water emulsion of the present invention is not particularly limited, but from the viewpoint of meltability in the mouth, it is more preferable that the S3 content be 2 wt% or less. This effect is particularly exhibited in the foamable oil-in-water emulsion.

[0032] The triacylglyceride compositions of fats and oils can be measured and determined by the high-performance liquid chromatography analysis (1) shown below. In this case, positional isomers, such as symmetrical and asymmetrical triacylglycerides, which have different bonding positions relative to the glycerol backbone, can be determined as the total amount without distinction. Furthermore, for triacylglycerides with the same constituent fatty acids, the positional isomer ratio (SSM (triglyceride in which S is bonded at the 1st and 2nd positions and M is bonded at the 3rd position, or S is bonded at the 2nd and 3rd positions and M is bonded at the 1st position) / S2M ratio) of symmetrical or asymmetrical triacylglycerides can be measured and determined by the high-performance liquid chromatography analysis (2). In any of the high-performance liquid chromatography analyses, the qualitative analysis of each triacylglyceride to be measured can be performed using commercially available reagents. High-performance liquid chromatographic analysis (1) can be performed using an ODS column, an acetone / acetonitrile 80 / 20 eluent, a liquid volume of 0.9 ml / min, a column temperature of 25°C, and a differential refractometer. High-performance liquid chromatographic analysis (2) can be performed according to the method described in Adlof, R. O. (1995). Analysis of triacylglycerol positional isomers by silver ion high performance liquid chromatography. Journal of high resolution chromatography, 18 (2), 105-107.

[0033] In one embodiment, the oil or fat having an S2Po / S2M weight ratio of 0.03 or more used in the oil-in-water emulsion and foamable oil-in-water emulsion of the present invention is preferably one or more oils or fats selected from the group consisting of sea buckthorn oil (seaberry fruit oil), bakhri fat, macadamia nut oil, hazelnut oil, and seal oil, from the viewpoints of purity and cost. More preferably, it is one or more oils or fats selected from the group consisting of sea buckthorn oil (seaberry fruit oil), macadamia nut oil, and bakhri fat. Even more preferably, it is macadamia nut oil and / or sea buckthorn oil (seaberry fruit oil). Most preferably, it is macadamia nut oil. These preferred oils or fats are Po-containing oils that contain Po derived from the raw material. Therefore, it is preferable that the oil-in-water emulsion and foamable oil-in-water emulsion of the present invention can be obtained by blending the Po-containing oil or fat itself or a Po-enriched fraction obtained by fractionation of the Po-containing oil or fat as a raw material. The method for fractionating fats and oils is not particularly limited, and may be, for example, solvent fractionation using acetone or hexane, or dry fractionation, but solvent fractionation is preferred because it allows Po to be concentrated to a high concentration. The Po content in the total fatty acid composition of the Po-containing fats and oils is preferably 0.8 wt% or more, more preferably 0.9 wt% or more, even more preferably 1.0 wt% or more, and most preferably 1.5 wt% or more.

[0034] In one embodiment, the oils and fats having an S2Po / S2M weight ratio of 0.03 or more used in the oil-in-water emulsion and foamable oil-in-water emulsion of the present invention can be exemplified by oils and fats obtained by transesterification of the oil-containing oil with an S (saturated fatty acid having 16 to 22 carbon atoms)-containing oil. The S-containing oil is not particularly limited, but examples thereof include oils and fats, fatty acids, and lower alcohol esters thereof. Fatty acids and / or lower alcohols thereof are preferred. Fatty acids are more preferred. The S content of the total fatty acid composition in the S-containing oil is preferably 8% by weight or more, more preferably 10% by weight or more, even more preferably 20% by weight or more, and most preferably 25% by weight or more. Similarly, the Po content of the total fatty acid composition in the Po-containing oil is preferably 0.8% by weight or more, more preferably 0.9% by weight or more, even more preferably 1.0% by weight or more, and most preferably 1.5% by weight or more. The interesterification may be carried out using an alkali metal catalyst or an enzyme-catalyzed interesterification method. In the interesterification method using an alkali metal catalyst, sodium methylate can be used, for example. For example, the reaction can be carried out by adding 0.1 to 0.5% by weight of sodium methylate to the oil / fat raw material. In the interesterification method using an enzyme catalyst, lipase can be used, for example. In this case, any lipase can be selected as long as it exhibits 1,3-enzyme interesterification activity or random interesterification activity. For example, 1 to 5% by weight of lipase derived from various microorganisms can be added to the oil / fat raw material and reacted at 40 to 70°C for 16 to 48 hours. In one embodiment, the oil / fat obtained by interesterification itself can be used in the oil-in-water emulsion and foamable oil-in-water emulsion of the present invention. In another embodiment, the oil / fat obtained by interesterification can be further treated, such as distilled or fractionated, and the resulting oil / fat can be used in the oil-in-water emulsion and foamable oil-in-water emulsion of the present invention. The conditions for further treatment such as distillation or fractionation may be those of known methods.

[0035] The content of various fatty acids in the total fatty acid composition of fats and oils can be measured by preparing fatty acid methyl esters in accordance with the method specified in the "Standard Methods for Analysis of Fats and Oils 2.4.1.2-2013 Methyl Esterification Method (Boron Trifluoride Methanol Method)" established by the Japan Oil Chemists' Society, and measuring the composition of fatty acids in accordance with the "Standard Methods for Analysis of Fats and Oils 2.4.2.3-2013 Fatty Acid Composition (Capillary Gas Chromatography Method)" established by the Japan Oil Chemists' Society.

[0036] The oil-in-water emulsion and foamable oil-in-water emulsion of the present invention may contain oils and fats other than those having an S2Po / S2M weight ratio of 0.03 or more, as long as the effects of the present invention are not impaired. Usable oils and fats are not particularly limited, but examples include 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, palm oil, shea butter, monkey fat, cocoa butter, coconut oil, palm kernel oil, and other vegetable oils and fats, as well as milk fat, beef tallow, lard, fish oil, whale oil, and other animal oils and fats, algae oil, and oils and fats derived from microbial fermentation. Examples include the above-mentioned oils and fats alone or in mixtures, or processed oils and fats obtained by hardening, fractionating, transesterifying, etc., of these oils and fats. Any of the oils and fats exemplified above can be used in the present invention.

[0037] The proportion of the oil phase in the oil-in-water emulsion and foamable oil-in-water emulsion of the present invention is preferably 10% by weight or more, more preferably 15% by weight or more. On the other hand, the proportion of the oil phase is preferably 50% by weight or less, more preferably 45% by weight or less, and most preferably 40% by weight or less. However, the oil phase includes all oils including milk fat. When the proportion of the oil phase in the foamable oil-in-water emulsion is appropriate, the foamable oil-in-water emulsion is less likely to become blobby (plasticized state), and appropriate foaming properties and shape retention can be obtained.

[0038] In addition to the above-mentioned oils and fats, additives such as proteins, emulsifiers, thickening polysaccharides, flavoring agents, sugars, flavorings, salts, vitamins, minerals, and other food ingredients can be added to the oil-in-water emulsion and foamable oil-in-water emulsion of the present invention as needed.

[0039] Examples of proteins that can be used include animal proteins and vegetable proteins. Examples of animal proteins that can be used include milk proteins derived from non-fat milk solids such as raw milk, cow's milk, skim milk, fresh cream, concentrated milk, evaporated milk, sweetened condensed milk, whole milk powder, skim milk powder, buttermilk powder, and whey protein; caseins such as acid casein, rennet casein, sodium caseinate, calcium caseinate, and potassium caseinate; and milk-derived proteins such as total milk protein. Among these, milk proteins derived from non-fat milk solids are preferred in terms of ease of use and flavor. Examples of vegetable proteins that can be used include vegetable protein materials derived from soybeans, peas, mung beans, chickpeas, pinto beans, coffee beans, pistachios, coconuts, sesame seeds, almonds, peanuts, macadamia nuts, hazelnuts, cashew nuts, walnuts, chestnuts, sunflower seeds, and other legumes, nuts, and seeds.

[0040] The emulsifier can be appropriately selected from emulsifiers commonly used in preparing oil-in-water emulsions, and examples thereof include synthetic emulsifiers such as glycerin fatty acid esters, polyglyceric acid fatty acid esters, sucrose fatty acid esters, sorbitan fatty acid esters, and propylene glycol fatty acid esters, as well as naturally occurring emulsifiers including lecithins such as soybean lecithin, egg yolk lecithin, and fractionated lecithins thereof, and further modified lecithins such as enzymatically hydrolyzed lysolecithin, and milk-derived phospholipids.

[0041] Examples of thickening polysaccharides include one or more selected from the group consisting of gellan gum, xanthan gum, locust bean gum, pullulan, guar gum, psyllium seed gum, water-soluble soybean polysaccharides, carrageenan, tamarind seed gum, and tara gum.Further examples include one or more selected from the group consisting of gellan gum, xanthan gum, pullulan, guar gum, psyllium seed gum, water-soluble soybean polysaccharides, carrageenan, and tamarind seed gum.

[0042] Examples of sugars include sucrose, fructose, glucose, lactose, maltose, invert sugar, trehalose, sugar alcohols, corn syrup, starch syrup, dextrin, etc. Examples of sugar alcohols include monosaccharide alcohols such as erythritol, mannitol, sorbitol, xylitol, etc., disaccharide alcohols such as isomaltitol, maltitol, lactitol, etc., trisaccharide alcohols such as maltotriitol, isomaltotriitol, panitol, etc., tetrasaccharide or higher sugar alcohols such as oligosaccharide alcohols, reduced starch saccharification products, reduced starch hydrolysates, etc.

[0043] Examples of salts include sodium phosphate, sodium polyphosphate, sodium tripolyphosphate, sodium metaphosphate, sodium hexametaphosphate, sodium citrate, trisodium citrate, monopotassium citrate, tripotassium citrate, etc. Further examples include alkali metal salts of organic acids such as succinic acid, lactic acid, carbonic acid, and acetic acid.

[0044] Examples of vitamins include ascorbic acid (vitamin C), riboflavin, pantothenic acid, folic acid, B vitamins, and other vitamins A, D, E, K, P, and the like.

[0045] Examples of minerals include sodium, potassium, magnesium, calcium, phosphorus, iodine, iron, copper, manganese, selenium, zinc, chromium, and molybdenum.

[0046] The method for producing the oil-in-water emulsion and foamable oil-in-water emulsion of the present invention is not particularly limited, but the following production method can be exemplified. First, oil-soluble ingredients such as an oil-soluble emulsifier and flavoring are mixed with dissolved oils and fats heated to 50 to 70°C, as needed, and the mixture is stirred while maintaining the temperature at 50 to 70°C to prepare an oil phase. Alternatively, water-soluble ingredients such as a water-soluble emulsifier, protein, salts, flavorings, thickeners, flavoring agents, sugars, dairy products, coloring agents, salt, vitamins, and minerals are mixed with warm water at 50 to 70°C, as needed, and the mixture is stirred while maintaining the temperature at 50 to 70°C to prepare an aqueous phase. The aqueous phase and oil phase are mixed with stirring and pre-emulsified. Subsequently, the oil-in-water emulsion and foamable oil-in-water emulsion of the present invention can be obtained by performing various treatments, such as micronization, homogenization, preheating, sterilization, primary cooling, secondary cooling, tertiary cooling, and aging, as needed, which are commonly performed.

[0047] The oil-in-water emulsion and the foamable oil-in-water emulsion thus obtained can be used as cooking cream, and the foamed emulsion can be used as whipped cream for toppings on ordinary decorated cakes, cream for artificial flowers, and as a filling for bread and confectionery.

[0048] The oil-in-water emulsion and foamable oil-in-water emulsion of the present invention are prevented from thickening or solidifying during refrigerated storage due to the appropriate weight ratio of the specific triglycerides contained therein. Furthermore, the foamable oil-in-water emulsion using the oil-in-water emulsion has good foaming properties, and by foaming the foamable oil-in-water emulsion, it is possible to produce whipped cream that melts in the mouth, has a cooling sensation, and is excellent in shape retention.

[0049] Examples are given below, but the technical concept of the present invention is not limited to these examples. In the examples, parts and percentages are all by weight.

[0050] ■Analysis Method ■Method of Fatty Acid Composition Analysis by Methylation The fatty acid composition of fats and oils was measured by preparing fatty acid methyl esters in accordance with the method specified in "Standard Methods for Analysis of Fats, Oils, and Related Compounds, 2.4.1.2 Methyl Esterification Method (Boron Trifluoride Methanol Method)" established by the Japan Oil Chemists' Society, and measuring them in accordance with "Standard Methods for Analysis of Fats, Oils, and Related Compounds, 2.4.2.3 Fatty Acid Composition (Capillary Gas Chromatography)" established by the Japan Oil Chemists' Society. ■Method of Analysis of Fat and Oil Composition (HPLC) The triacylglyceride composition of fats and oils can be measured and determined by the high performance liquid chromatography analysis (1) shown below. In this case, positional isomers with different bonding positions to the glycerin skeleton, such as symmetrical and asymmetrical triacylglycerides, can be determined as the combined amount without distinction. Furthermore, in triacylglycerides having the same constituent fatty acids, the positional isomer ratio (SSM (triglyceride with S at the 1- and 2-positions and M at the 3-position, or S at the 2- and 3-positions and M at the 1-position) / S2M ratio) of symmetric or asymmetric triacylglycerides can be measured and determined by high-performance liquid chromatography (2). In both high-performance liquid chromatography analyses, the qualitative analysis of each triacylglyceride to be measured was carried out using commercially available reagents. High-performance liquid chromatography (1) was carried out using (column: ODS, eluent: acetone / acetonitrile = 80 / 20, liquid volume: 0.9 ml / min, column temperature: 25°C, detector: differential refractometer). High-performance liquid chromatography (2) was carried out according to the method described in Adlof, R. O. (1995). Analysis of triacylglycerol positional isomers by silver ion high performance liquid chromatography. Journal of High Resolution Chromatography, 18 (2), 105-107. This was carried out in accordance with the method described therein.

[0051] ■ Experiment 1-1: Effect of S2Po on Oil-in-Water Emulsions 1. Oil-in-water emulsions were prepared using S2Po, whose S component was primarily palmitic acid, to evaluate the effect of S2Po on thickening and solidification during refrigerated storage (stock solution stability). ■ Preparation of Oils and Fat: Oil A was the mid-melting point palm fraction (iodine value 34, Fuji Oil) and Oil B was the mid-melting point palm fraction (iodine value 45.5, Fuji Oil). Macadamia nut oil (macadamia nut oil) was used as the raw oil and fat, and 1,3-enzymatic interesterification with palmitic acid was performed. The fatty acid fraction was then distilled off. The resulting oil and fat fraction was subjected to multi-stage solvent fractionation to obtain P2Po-rich oils C, F, and G. These oils were blended to obtain oils D and E with various P2Po contents. Further, extremely hardened palm kernel oil (iodine value 2.5, Fuji Oil) was designated as fat H. The triglyceride compositions of fats A to G are shown in Table 1, and the fatty acid compositions of fats A to H are shown in Table 2. The triglyceride composition of fat H was not measurable and is therefore not shown. Fat A to H were mixed to obtain fats 1 to 13 and fats 1' to 4'. The triglyceride compositions of the obtained fats are shown in Table 3, and the fatty acid compositions are shown in Table 4.

[0052] Table 1 Triglyceride composition of fats and oils A to G

[0053] Table 2: Fatty acid composition of oils A to H

[0054] Table 3-1 Triglyceride composition of oils 1 to 5 and oils 1' to 2'

[0055] Table 3-2 Triglyceride composition of fats and oils 6-13 and 3'-4'

[0056] Table 4-1 Fatty acid composition of oils 1 to 5 and oils 1' to 2'

[0057] Table 4-2 Fatty acid composition of oils 6-13 and oils 3'-4'

[0058] ■ Preparation of Oil-in-Water Emulsions <Examples 1A to 13A, Comparative Examples 1A to 4A> The obtained oil was melted at a temperature of 65°C or higher to form an oil phase. Furthermore, an aqueous phase was prepared by dissolving 0.25 parts of polyglycerol saturated fatty acid ester (HLB 11.6) in 79.75 parts of warm water maintained at 70°C. 20 parts of the oil phase was added to the aqueous phase, and the resulting two-phase liquid was emulsified by stirring (4000 rpm) with a homogenizer. This preliminary emulsion was treated at a homogenization pressure of 7.0 MPa, after which 6 mL was filled into a 10 mL test tube and cooled to 5°C in a chiller to obtain the oil-in-water emulsions of Examples 1A to 13A and Comparative Examples 1A to 4A. <Examples 1B to 13B, Comparative Examples 1B to 4B> Oil-in-water emulsions of Examples 1B to 13B and Comparative Examples 1B to 4B were obtained in the same manner as Examples 1A to 13A and Comparative Examples 1A to 4A, except that the amount of hot water was changed to 74.75 parts and the amount of oil phase was changed to 25 parts. <Examples 1C to 13C, Comparative Examples 1C to 4C> Oil-in-water emulsions of Examples 1C to 13C and Comparative Examples 1C to 4C were obtained in the same manner as Examples 1A to 13A and Comparative Examples 1A to 4A, except that the amount of hot water was changed to 69.75 parts and the amount of oil phase was changed to 30 parts. <Examples 1D to 13D, Comparative Examples 1D to 4D> Oil-in-water emulsions of Examples 1D to 13D and Comparative Examples 1D to 4D were obtained in the same manner as Examples 1A to 13A and Comparative Examples 1A to 4A, except that the amount of hot water was changed to 59.75 parts and the amount of oil phase was changed to 40 parts.

[0059] ■ Evaluation of thickening and solidification inhibition The obtained oil-in-water emulsion was allowed to stand in a 5°C refrigerator, and the state of the oil-in-water emulsion was evaluated on the 2nd, 7th, and 14th days. When the test tube was tilted 90 degrees and held for 5 seconds, emulsions that were fluid and maintained a liquid state were given a score of 3, emulsions that showed some thickening but were fluid were given a score of 2, and emulsions that had completely solidified and lost fluidity were given a score of 1. A score of 2 or more was evaluated as having a high effect of inhibiting thickening and solidification during refrigerated storage (stock solution stability). Test plots that received a score of 2 or more on the 14th day of storage were considered to have passed the test. The results are summarized in Tables 5 to 8.

[0060] Table 5-1 Evaluation of stability of undiluted oil-in-water emulsions of Examples 1A to 5A and Comparative Examples 1A to 2A

[0061] Table 5-2 Evaluation of the stability of the oil-in-water emulsion concentrates of Examples 6A to 13A and Comparative Examples 3A to 4A

[0062] Compared to Comparative Example 1A, the oil-in-water emulsions of Examples 1A to 4A maintained their fluidity over a long period of time, and thickening and solidification during refrigerated storage were suppressed. It was confirmed that an increase in S2Po improved the thickening and solidification suppression effect during refrigerated storage. Comparative Example 2A, which had a low S2M content, exhibited a higher thickening and solidification suppression effect during refrigerated storage than Comparative Example 1A, but thickening and solidification were also observed during long-term storage. In contrast, Example 5A remained liquid even after 14 days, demonstrating that the addition of S2Po improved the thickening and solidification suppression effect during refrigerated storage even when the S2M content was low. Comparative Examples 3A and 4A, which had a high S2M content, solidified as early as the second day of refrigerated storage, while Examples 6A to 13A maintained their liquid state, demonstrating that S2Po improved the thickening and solidification suppression effect during refrigerated storage even when the S2M concentration was high.

[0063] Table 6-1 Evaluation of stability of undiluted oil-in-water emulsions of Examples 1B to 5B and Comparative Examples 1B to 2B

[0064] Table 6-2 Evaluation of stability of undiluted oil-in-water emulsions of Examples 6B to 13B and Comparative Examples 3B to 4B

[0065] Table 7-1 Evaluation of stability of undiluted oil-in-water emulsions of Examples 1C to 5C and Comparative Examples 1C to 2C

[0066] Table 7-2 Evaluation of stability of undiluted oil-in-water emulsions of Examples 6C to 13C and Comparative Examples 3C to 4C

[0067] Table 8-1 Evaluation of stability of undiluted oil-in-water emulsions of Examples 1D to 5D and Comparative Examples 1D to 2D

[0068] Table 8-2 Evaluation of stability of undiluted oil-in-water emulsions of Examples 6D to 13D and Comparative Examples 3D to 4D

[0069] Although an increase in oil content tends to cause thickening, it was confirmed that Examples 1B to 13B, 1C to 13C, and 1D to 13D maintained fluidity even after 14 days of refrigerated storage, and were highly effective in inhibiting thickening and solidification during refrigerated storage.

[0070] ■ Experiment 1-2 Evaluation of Foamable Oil-in-Water Emulsions ■ Preparation of Foamable Oil-in-Water Emulsions <Examples 1E to 4E, Comparative Example 1E> 0.1 parts soybean lecithin, 0.28 parts polyglycerol unsaturated fatty acid ester (HLB 8.8), and 0.06 parts glycerol fatty acid ester (HLB 4.3) were added to 25 parts of Oils and Fat 1 to 4 or Oil and Fat 1' and dissolved at 65°C to prepare an oil phase. Separately, 0.025 parts sucrose fatty acid ester (HLB 5), 0.2 parts sodium hexametaphosphate, 0.02 parts sodium bicarbonate, 0.1 parts xanthan gum, 4 parts skim milk powder, 5 parts sweetened condensed milk, and 1 part filtered egg yolk were added to 75 parts of warm water kept at 65°C and dissolved at 65°C to prepare an aqueous phase. The oil phase was added to the water phase and emulsified by stirring (7000 rpm) with a homomixer for 30 minutes. This preliminary emulsion was treated at a homogenization pressure of 7.0 MPa and then immediately cooled to 5°C. After cooling, the mixture was aged for 48 hours to obtain foamable oil-in-water emulsions of Examples 1E to 4E or Comparative Example 1E. <Example 5E, Comparative Example 2E> 0.1 part of soybean lecithin, 0.28 part of polyglycerol unsaturated fatty acid ester (HLB 8.8), and 0.06 part of glycerol fatty acid ester (HLB 4.3) were added to 30 parts of Oil 5 or Oil 2' and dissolved at 65°C to prepare an oil phase. Separately, 70 parts of warm water kept at 65°C were added with 0.025 parts of sucrose fatty acid ester (HLB 5), 0.2 parts of sodium hexametaphosphate, 0.02 parts of sodium bicarbonate, 0.1 parts of xanthan gum, 4 parts of skim milk powder, 5 parts of sweetened condensed milk, and 1 part of filtered egg yolk, and dissolved at 65°C to prepare an aqueous phase. The oil phase was added to the aqueous phase and emulsified by stirring (7000 rpm) with a homomixer for 30 minutes. This preliminary emulsion was treated at a homogenization pressure of 7.0 MPa and then immediately cooled to 5°C. After cooling, the mixture was aged for 48 hours to obtain a foamable oil-in-water emulsion of Example 5E or Comparative Example 2E. (iii) Evaluation of emulsion stability (stability of undiluted solution) The viscosity was measured on the second day (after 48 hours of aging) and on the 14th day of refrigerated storage using a digital viscometer TV-10 (manufactured by TOKI SANGYO) with a No. 2 rotor at 60 rpm, and the viscosity change rate was calculated as the viscosity on the 14th day divided by the viscosity on the second day. A viscosity change rate of less than 1.3 was given 3 points, 1.3 to less than 1.5 was given 2 points, and 1.5 or more was given 1 point, with a score of 2 or more being evaluated as having good emulsion stability.■ Foaming property evaluation: 40 g of sugar was added to 500 g of foaming oil-in-water emulsion, and the mixture was whipped at 3 speed (300 rpm) in a Hobart mixer (HOBART CORPORATION, Model N-5) at 20°C in a room. The time required to reach optimal foaming was measured. A score of 3 was given for less than 2 minutes, a score of 2 for 2 to 3 minutes, and a score of 1 for 3 minutes or more. A score of 2 or higher was considered to be good foaming property. ■ Shape retention evaluation: The foamed artificial flowers were stored at 15°C for 24 hours. A score of 3 was given for a state in which the water release and artificial flower state remained unchanged from immediately after the flower was created, a score of 2 for a state in which about 1 / 4 of the bottom surface had sunk, and a score of 1 for a state in which about 1 / 2 of the bottom surface had sunk. A score of 2 or higher was considered to be good shape retention. ■ Evaluation of melt-in-the-mouth and cooling sensation Six experienced panelists gave 3 points for excellent melt-in-the-mouth and cooling sensation, 2 points for excellent melt-in-the-mouth and cooling sensation, and 1 point for something that remains in the mouth and has no cooling sensation. A score of 2 or more was considered to be good melt-in-the-mouth and cooling sensation. A score of 2 or more for all of the above four items was considered to be a pass in the overall evaluation. The evaluation results for the above four items are summarized in Table 9.

[0071] Table 9: Evaluation of foamable oil-in-water emulsions of Examples 1E to 5E and Comparative Examples 1E and 2E

[0072] Comparative Examples 1E and 2E showed significant thickening after 14 days of storage, while Examples 1E to 5E demonstrated this was suppressed. Furthermore, the foaming time was less than 3 minutes in all cases, demonstrating good foaming properties. Shape retention after foaming was also good in all cases. Regarding melt-in-the-mouth and cooling sensation, Comparative Examples 1E and 2E left a residue in the mouth, but Examples 1E to 5E were found to be satisfactory.

[0073] Experiment 2: Effect of S2Po on Oil-in-Water Emulsions (2) Oil-in-water emulsions were prepared using S2Po with a low SSM / S2M ratio and S primarily consisting of palmitic acid. The effect of S2Po on thickening and solidification during refrigerated storage (stock solution stability) was examined. Preparation of Oils and Fat: High-oleic sunflower oil was used as the raw material for 1,3-position enzymatic interesterification with palmitic acid. The fatty acid fraction was then distilled off. The resulting oil and fat fraction was subjected to multistage solvent fractionation to obtain oil I, which was rich in P2O (a triglyceride consisting of two palmitic acids (P) and one oleic acid (O)). Similarly, macadamia nut oil was used as the raw material for enzymatic interesterification and distillation / fractionation to obtain oils K and M, which were rich in P2Po. These oils were blended to obtain oils J and L, each with a different P2Po content. The triglyceride compositions of fats I to M are shown in Table 10, and the fatty acid compositions of fats I to M and H are shown in Table 11. Fats I to M and H were mixed to obtain fats 14 to 17 and fat 5'. The triglyceride compositions of the obtained fats are shown in Table 12, and the fatty acid compositions are shown in Table 13.

[0074] Table 10 Triglyceride composition of fats and oils I to M

[0075] Table 11 Fatty acid composition of oils I to M and oil H

[0076] Table 12 Triglyceride composition of fats and oils 14 to 17 and fat 5'

[0077] Table 13 Fatty acid composition of oils 14-17 and oil 5'

[0078] ■ Preparation of oil-in-water emulsions The obtained oils and fats were used to obtain oil-in-water emulsions of Examples 14 to 17 and Comparative Example 5 in the same manner as in Examples 1A to 13A and Comparative Examples 1A to 4A. ■ Evaluation of stock solution stability The obtained oil-in-water emulsions were evaluated for stock solution stability in the same manner as in Experiment 1-1. Test plots that scored 2 or more points after 14 days of storage were considered to have passed. The results are summarized in Table 14.

[0079] Table 14: Evaluation of stability of undiluted oil-in-water emulsions of Examples 14 to 17 and Comparative Example 5

[0080] In comparison with Comparative Example 5, Examples 14 to 17 maintained fluidity even after 14 days of refrigerated storage, demonstrating a high effect of inhibiting thickening and solidification during refrigerated storage. From the above, it was determined that the addition of S2Po improved the effect of inhibiting thickening and solidification during refrigerated storage, regardless of the SSM / S2M value.

[0081] ■ Experiment 3: Effect of S2Po on Oil-in-Water Emulsions 3 Oil-in-water emulsions were prepared using S2Po, where S was primarily palmitic acid or stearic acid, and the effect of S2Po on thickening and solidification during refrigerated storage (stock solution stability) was examined. ■ Preparation of Fats and Oils: Cocoa butter was used as fat N. Furthermore, macadamia nut oil was used as a raw material and a mixture of palmitic acid and stearic acid was subjected to 1,3-enzymatic interesterification, and the fatty acid fraction was removed by distillation. The resulting fat and oil fraction was subjected to multistage fractionation using a solvent to obtain fat R, which was rich in PPoSt. By blending fat N and fat R, fats O to Q with various PPoSt contents were obtained. Furthermore, high oleic sunflower oil was used as a raw material and 1,3-enzymatic interesterification was performed with stearic acid, and the fatty acid fraction was removed by distillation. The obtained fat fraction was subjected to multistage fractionation using a solvent to obtain fat S rich in St2O. Furthermore, fat W rich in St2Po was obtained using macadamia nut oil as a feedstock through 1,3-enzyme interesterification, distillation, and fractionation in the same manner as above. By blending these obtained fats and oils, fats T to V with various St2Po contents were obtained. The triglyceride compositions of fats N to W are shown in Table 15, and the fatty acid compositions of fats N to W and fat H are shown in Table 16. Fat N to W and fat H were blended to obtain fats 18 to 25 and fats 6' to 7'. The triglyceride compositions of the obtained fats and oils are shown in Table 17, and the fatty acid compositions are shown in Table 18.

[0082] Table 15 Triglyceride composition of fats and oils N to W

[0083] Table 16 Fatty acid composition of oils N to W and oil H

[0084] Table 17 Triglyceride composition of fats and oils 18-25 and 6'-7'

[0085] Table 18 Fatty acid composition of oils 18-25 and oils 6'-7'

[0086] ■ Preparation of oil-in-water emulsions The obtained oils and fats were used to obtain oil-in-water emulsions of Examples 18 to 25 and Comparative Examples 6 and 7 in the same manner as in Examples 1A to 13A and Comparative Examples 1A to 4A. ■ Evaluation of stock solution stability The obtained oil-in-water emulsions were evaluated for stock solution stability in the same manner as in Experiment 1-1. Test plots that scored 2 or more points after 14 days of storage were considered to have passed. The results are summarized in Table 19.

[0087] Table 19: Evaluation of stability of undiluted oil-in-water emulsions of Examples 18 to 25 and Comparative Examples 6 to 7

[0088] In comparison with Comparative Examples 6 and 7, it was confirmed that Examples 18 to 25 maintained fluidity even after 14 days of refrigerated storage, and were highly effective in inhibiting thickening and solidification during refrigerated storage.

[0089] The present invention can provide an oil-in-water emulsion that is inhibited from thickening or solidifying during refrigerated storage. Furthermore, a foamable oil-in-water emulsion using this oil-in-water emulsion has good foaming properties. Furthermore, whipped cream obtained by whipping this foamable oil-in-water emulsion has excellent melt-in-the-mouth properties, a cooling sensation, and good shape retention.

Claims

1. An oil-in-water emulsion containing an oil or fat having a weight ratio of S2Po / S2M of 0.03 or more. S2Po is a triglyceride in which two S's and one Po are bonded, and S2M is a triglyceride in which two S's and one M are bonded. Here, S means a saturated fatty acid having 16 to 22 carbon atoms, Po means palmitoleic acid (C16:1(n-7)), and M means a monounsaturated fatty acid having 16 to 22 carbon atoms.

2. The oil-in-water emulsion according to claim 1, wherein the weight ratio of Po / M in the oil is 0.03 or more, where Po is palmitoleic acid (C16:1(n-7)) and M is a monounsaturated fatty acid having 16 to 22 carbon atoms.

3. An oil-in-water emulsion according to claim 1 or 2, wherein the Po content in the oil or fat is 0.3% by weight or more.

4. The oil-in-water emulsion according to claim 1 or 2, wherein the weight ratio of P2Po / S2M in the oil or fat is 0.03 or more. P2Po is a triglyceride in which two P's and one Po are bonded, where P represents palmitic acid.

5. The oil-in-water emulsion according to claim 1 or 2, wherein the weight ratio of PPoSt / S2M in the oil or fat is 0.01 or more. PPoSt is a triglyceride composed of one P, one Po, and one St, where P represents palmitic acid and St represents stearic acid.

6. The oil-in-water emulsion according to claim 1 or 2, wherein the weight ratio of St2Po / S2M in the oil or fat is 0.02 or more. St2Po is a triglyceride in which two St and one Po are bonded, where St means stearic acid.

7. The oil-in-water emulsion according to claim 3, wherein the weight ratio of P2Po / S2M in the oil or fat is 0.03 or more. P2Po is a triglyceride consisting of two P's and one Po, where P represents palmitic acid.

8. The oil-in-water emulsion according to claim 3, wherein the weight ratio of PPoSt / S2M in the oil or fat is 0.01 or more. PPoSt is a triglyceride composed of one P, one Po, and one St, where P represents palmitic acid and St represents stearic acid.

9. The oil-in-water emulsion according to claim 3, wherein the weight ratio of St2Po / S2M in the oil or fat is 0.02 or more. St2Po is a triglyceride consisting of two St and one Po bonded together, where St means stearic acid.

10. The oil-in-water emulsion according to claim 1 or 2, which is a foamable oil-in-water emulsion.

11. The oil-in-water emulsion of claim 3, which is a foaming oil-in-water emulsion.

12. The oil-in-water emulsion of claim 4, which is a foaming oil-in-water emulsion.

13. The oil-in-water emulsion of claim 5, which is a foaming oil-in-water emulsion.

14. The oil-in-water emulsion of claim 6, which is a foaming oil-in-water emulsion.

15. The oil-in-water emulsion of claim 7, which is a foaming oil-in-water emulsion.

16. The oil-in-water emulsion of claim 8, which is a foaming oil-in-water emulsion.

17. The oil-in-water emulsion of claim 9, which is a foaming oil-in-water emulsion.

18. Whipped cream whipped with the foamable oil-in-water emulsion according to claim 10.

19. Whipped cream whipped with the foamable oil-in-water emulsion of claim 11.

20. Whipped cream obtained by whipping the foamable oil-in-water emulsion according to claim 12.

21. Whipped cream obtained by whipping the foamable oil-in-water emulsion according to claim 13.

22. Whipped cream obtained by whipping the foamable oil-in-water emulsion according to claim 14.

23. Whipped cream obtained by whipping the foamable oil-in-water emulsion according to claim 15.

24. Whipped cream obtained by whipping the foamable oil-in-water emulsion according to claim 16.

25. Whipped cream whipped with the foamable oil-in-water emulsion of claim 17.

26. A method for producing an oil-in-water emulsion or a foamable oil-in-water emulsion, comprising mixing an oil phase containing an oil or fat having an S2Po / S2M weight ratio of 0.03 or more with an aqueous phase containing at least water to emulsify the oil-in-water emulsion. S2Po is a triglyceride in which two S's and one Po are bonded, and S2M is a triglyceride in which two S's and one M are bonded. Here, S is a saturated fatty acid having 16 to 22 carbon atoms, Po is palmitoleic acid (C16:1(n-7)), and M is a monounsaturated fatty acid having 16 to 22 carbon atoms.

27. A method for producing an oil-in-water emulsion or a foamable oil-in-water emulsion according to claim 26, wherein the weight ratio of Po / M in the oil or fat is 0.03 or more.

28. A method for producing an oil-in-water emulsion or a foamable oil-in-water emulsion according to claim 26 or 27, wherein the Po content in the oil or fat is 0.3% by weight or more.

29. A method for producing an oil-in-water emulsion or a foamable oil-in-water emulsion according to claim 26 or 27, wherein the weight ratio of P2Po / S2M in the oil or fat is 0.03 or more. P2Po is a triglyceride in which two P's and one Po are bonded, where P represents palmitic acid.

30. A method for producing an oil-in-water emulsion or a foamable oil-in-water emulsion according to claim 26 or 27, wherein the weight ratio of PPoSt / S2M in the oil or fat is 0.01 or more. PPoSt is a triglyceride having one P, one Po, and one St bonded thereto, where P represents palmitic acid and St represents stearic acid.

31. A method for producing an oil-in-water emulsion or a foamable oil-in-water emulsion according to claim 26 or 27, wherein the weight ratio of St2Po / S2M in the oil or fat is 0.02 or more. St2Po is a triglyceride consisting of two St and one Po bonded together, where St represents stearic acid.

32. A method for producing an oil-in-water emulsion or a foamable oil-in-water emulsion according to claim 28, wherein the weight ratio of P2Po / S2M in the oil or fat is 0.03 or more. P2Po is a triglyceride consisting of two P's and one Po, where P stands for palmitic acid.

33. A method for producing an oil-in-water emulsion or a foamable oil-in-water emulsion according to claim 28, wherein the weight ratio of PPoSt / S2M in the oil or fat is 0.01 or more. PPoSt is a triglyceride having one P, one Po, and one St bonded thereto, where P represents palmitic acid and St represents stearic acid.

34. A method for producing an oil-in-water emulsion or a foamable oil-in-water emulsion according to claim 28, wherein the weight ratio of St2Po / S2M in the oil or fat is 0.02 or more. St2Po is a triglyceride consisting of two St and one Po bonded together, where St represents stearic acid.

35. A method for suppressing thickening and solidification during refrigerated storage by including in an oil-in-water emulsion or a foamable oil-in-water emulsion an oil or fat having an S2Po / S2M weight ratio of 0.03 or more. S2Po is a triglyceride in which two S's and one Po are bonded, and S2M is a triglyceride in which two S's and one M are bonded. Here, S means a saturated fatty acid having 16 to 22 carbon atoms, Po means palmitoleic acid (C16:1(n-7)), and M means a monounsaturated fatty acid having 16 to 22 carbon atoms.

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