JP7511366B2 - Frozen dessert and its manufacturing method - Google Patents

Description

The present invention relates to frozen desserts and a method for producing frozen desserts.

Regarding frozen desserts in which the main body of the dessert is coated with chocolate, Patent Document 1 proposes physical properties of chocolate that are suitable for use as a coating layer for the frozen dessert.
Furthermore, Patent Document 2 proposes a method for forming a uniform chocolate coating layer on the outer surface of a frozen dessert.

JP 2012-244920 A JP 2016-123297 A

According to the findings of the present inventors, the methods described in Patent Documents 1 and 2 do not necessarily provide a sufficient balance of melting in the mouth, balance of taste, and richness of taste when the frozen dessert body and coating layer are eaten together. A good balance of melting in the mouth means that there is a small difference in the speed at which the frozen dessert body and coating layer melt in the mouth, and a good balance of taste means that the time during which the tastes of both the frozen dessert body and coating layer can be felt is long. A good richness of taste means that the speed at which the frozen dessert body and coating layer melt in the mouth is not too fast, and both tastes can be felt sufficiently.
Furthermore, in the case of frozen desserts having a coating layer on the outer surface of the frozen dessert body, defects in appearance may occur due to temperature changes or impacts when the dessert is purchased at a store and carried home.

The present invention aims to provide a frozen dessert that has an excellent balance of melting in the mouth, flavor balance, and richness when the frozen dessert body and coating layer are eaten together, and also has excellent resistance to temperature changes and impacts.

The present invention has the following aspects.
[1] A frozen dessert comprising a frozen dessert body and a coating layer made of an oil or fat composition, 90-100% of the outer surface of the frozen dessert body being covered with the coating layer, a mass ratio of the frozen dessert body to the coating layer being 3:1-6:1, an overrun of the frozen dessert body being 5-60%, an SFC (solid fat content) of the oil or fat composition at -10°C being 20-60%, and a difference obtained by subtracting the SFC at 20°C from the SFC at -10°C being 20-55%.
[2] The frozen confectionery according to [1], wherein the difference between the SFC at -10°C and the SFC at 10°C of the oil and fat composition is 15% or more.
[3] A method for producing a frozen dessert, comprising the steps of: cooling a raw material mix while incorporating air to obtain a partially frozen product having an overrun of 5 to 60%, shaping the partially frozen product, cooling and solidifying it to obtain a frozen dessert body, covering 90 to 100% of the outer surface of the frozen dessert body with a coating liquid made of an oil and fat composition, and cooling and hardening the coating liquid to form a coating layer to obtain the frozen dessert, wherein an oil and fat composition is used as the oil and fat composition having an SFC (solid fat content) at -10°C of 20 to 60% and a difference obtained by subtracting the SFC at 20°C from the SFC at -10°C of 20 to 55%, and the mass ratio of the frozen dessert body to the coating layer is 3:1 to 6:1.
[4] The method for producing a frozen dessert according to [3], wherein the temperature of the coating liquid is T°C (25≦T≦50), and the viscosity of the coating liquid at T°C is 250 to 550 mPa·s.

According to the present invention, a frozen dessert can be obtained that has an excellent balance of melting in the mouth, flavor balance, and richness when the frozen dessert body and coating layer are eaten together, and also has excellent resistance to temperature changes and impacts.

FIG. 2 is a perspective view showing an example of the product shape of the frozen dessert of the present invention. 1 is a graph showing the SFC measurement results of the oil and fat compositions used in the examples.

The following definitions of terms apply throughout the specification and claims.
Unless otherwise specified, a numerical range expressed by "-" means a numerical range in which the numerical values before and after "-" are the lower and upper limits.
In this specification, the SFC (solid fat content) of an oil or fat composition at a° C. may be expressed as "SFC (a° C.)".
In this specification, the difference obtained by subtracting the SFC at c°C from the SFC at b°C of an oil or fat composition is sometimes referred to as the "difference in SFC(b°C)-SFC(c°C)".

The frozen dessert in the present invention includes those generally classified as "frozen desserts" and frozen yogurt. Specific examples of the "frozen desserts" include ice creams (ice cream, ice milk, lacto ice cream) and frozen desserts.
Ice cream refers to processed foods made from milk or milk-based foods, or frozen foods that use milk or milk-based foods as the main ingredient, that contain 3.0% or more milk solids (excluding fermented milk). Ice cream is classified into three types, ice cream, ice milk, and lacto ice cream, depending on the amount of milk solids and milk fat they contain.
On the other hand, those with a milk solids content of less than 3.0% are not classified as ice creams, but are regulated as frozen desserts in the Ministry of Health, Labour and Welfare's "Standards and Criteria for Foods, Additives, etc." based on the Food Sanitation Law.
Frozen yogurt is classified as "fermented milk" by the Ministerial Ordinance on the Ingredient Standards for Milk and Dairy Products. Fermented milk is defined as "a product made by fermenting milk or milk containing an equivalent or higher amount of non-fat milk solids with lactic acid bacteria or yeast into a paste or liquid form, or by freezing these products," and the ingredient standard is stipulated as "non-fat milk solids of 8.0% or more, and lactic acid bacteria or yeast count of 10 million/mL or more." Frozen yogurt is classified as frozen fermented milk.
The frozen dessert in the present invention may be any of frozen desserts, ice cream, ice milk, lacto ice cream, and frozen yogurt.

The freezing point is the temperature at which a liquefied sample stops decreasing due to the exothermic reaction that occurs when the liquid turns into a solid (solidification point) when the product temperature is measured over time while the liquid sample is cooled at an ambient temperature of -25°C.
The viscosity of the coating liquid was measured using a Brookfield type viscometer with a rotor No. 2 at a rotation speed of 12 rpm, and the value was measured after 30 seconds.

The content of components, etc. is measured by the following methods.
(1) Moisture content: Measured by normal pressure heating and drying method (drying aid addition method).
(2) Solids Content Calculated as solids content (mass %) = 100 - moisture (mass %).

(3) Fat and milk fat of frozen desserts themselves: Measured in accordance with the method for quantifying milk fat in ice cream products as set forth in the Ministerial Ordinance on the Compositional Standards of Milk and Dairy Products.
Specifically, 4 g of sample is placed in a small beaker, 3 mL of water is added, mixed well, and transferred to a Roerich tube. The beaker is thoroughly washed with 3 mL of water, and the washings are added to the Roerich tube and shaken. Next, 2 mL of ammonia water (a 25-30% aqueous solution of ammonia, colorless and transparent) is added and gently mixed. Next, the Roerich tube is placed in a 60°C water bath and heated for 20 minutes while occasionally shaking. Further, 2 mL of ethanol (95-96% aqueous solution) and 10 mL of ethanol are added and mixed well.
Next, add 25 mL of ether to the Roerich tube and gently rotate it. When the color becomes uniform, release the ether gas and shake the tube horizontally and vigorously for 30 seconds. Next, add 25 mL of petroleum ether (boiling point 60°C or less), shake for 30 seconds in the same way, loosen the stopper, and leave it upright for at least 2 hours until the supernatant becomes transparent. Place the supernatant in a beaker whose weight has been determined in advance.
Add 25 mL of ether and 25 mL of petroleum ether to the Roerich tube in the same manner as above, mix, and pour the supernatant into the beaker. Wash the tip of the side tube with an equal mixture of ether and petroleum ether and add it to the beaker.
The beaker is heated to about 75° C. to volatilize the solvent, and then dried for 1 hour in a dryer at an atmospheric temperature of 100 to 105° C., and then weighed. The increase in the weight of the beaker from the constant weight is regarded as the fat content.
When the sample does not contain any fat other than milk fat, the fat content determined above is regarded as the milk fat content.
When the sample contains fats other than milk fat, the milk fat content is calculated by subtracting the amount of the other fats from the fat content calculated above.

(4) Non-fat milk solids: Measured using a method conforming to the quantitative determination of non-fat milk solids in fermented milk and lactic acid bacteria beverages set forth in the Ministerial Ordinance on the Compositional Standards of Milk and Dairy Products.
Specifically, accurately weigh out about 50 g of the sample (if frozen, melt it completely at a temperature of 40°C or less in the shortest possible time) and add a few drops of phenolphthalein solution. While stirring, gradually add 10% sodium hydroxide solution to make it slightly alkaline, and place in a measuring flask. Add water to make it 100 mL, and precisely place 5 mL of that in a 150 mL Kjeldahl digestion flask. Add 0.2 g of a mixed powder of 9 g of potassium sulfate and 1 g of copper sulfate, and then add 10 mL of sulfuric acid through the inner wall of the flask. Next, gradually heat the flask, and when white smoke of sulfurous acid gas is generated, turn the heat up a little. After most of the bubbles have disappeared, heat it strongly, and when the liquid inside turns a transparent pale blue color and no carbon is visible on the inner wall of the flask, stop heating. After cooling, carefully add 30 mL of water, cool it again, and then connect the flask to a distillation apparatus. In this case, 30 mL of 0.05 mol/L sulfuric acid and a few drops of methyl red solution are placed in a 200 mL absorption flask, and the bottom of the condenser is immersed in the liquid.
Next, pour 40 mL of 30% sodium hydroxide solution into the funnel of the Kjeldahl distillation apparatus, wash it down with 10 mL of water, close the pinch cock, and immediately begin distillation. When the amount of distillate reaches 80-100 mL, remove the bottom end of the condenser from the liquid surface and take a few more mL of distillate. After distillation is complete, wash the part of the condenser that was immersed in the liquid with a small amount of water, combine the washings with the liquid in the absorption flask, and titrate this with 0.1 mol/L sodium hydroxide solution.
The non-fat milk solids (unit: mass %) is calculated according to the following formula.
Non-fat milk solids = {0.0014 x (A - B)} / sample amount (unit: g) x 6.38 x 2.82 x 100
A: The amount of 0.1 mol/L sodium hydroxide solution required to neutralize 30 mL of 0.05 mol/L sulfuric acid (unit: mL)
B: Amount of 0.1 mol/L sodium hydroxide solution required for titration (unit: mL)
Indicator: Methyl red solution (dissolve 1 g of methyl red in 50 mL of ethanol, add water to make 100 mL, and filter if necessary.
(5) Milk solids The total of the milk fat content determined by the method in (3) above and the non-fat milk solids content determined by the method in (4) above is defined as the milk solids content.

(6) Oil and Fat Content of Oil and Fat Composition The method for measuring lipids is based on the ether extraction method disclosed in "Methods of Analysis of Nutritional Components, etc. in the Nutrition Labeling Standards" (Eishin No. 13, April 26, 1999).
Specifically, the sample is placed in a cylindrical filter paper, lightly packed with absorbent cotton, and then placed in an extraction tube. The receiving flask is dried in advance in an electric constant temperature dryer at 100-105°C for 1-2 hours, transferred to a desiccator, cooled for 1 hour, and weighed to the nearest 0.1 mg to determine the constant weight (W0g). About 2/3 volume of ether is added to this, a cooling tube is connected, and extraction is performed in an electric constant temperature water bath for 8-16 hours. After the extraction is completed, the extraction tube is quickly removed, the cylindrical filter paper is taken out with tweezers, reconnected to the cooling tube, and heated in an electric constant temperature water bath. When almost all of the ether in the flask has been transferred to the extraction tube, the flask is removed and further heated to completely evaporate the ether in the flask. The outside of the flask is wiped with gauze, placed in an electric constant temperature dryer at 100-105°C, dried for 1 hour, transferred to a desiccator, cooled, and then weighed to determine the constant weight (W1g). The fat/oil content in the sample (g/100 g) is calculated using the following formula:
Content of fats and oils in sample (g/100g)=(W1-W0)/W×100
W: sample amount (g)
(7) SFC (Solid Fat Content) of the Oil Composition
"SFC" (Solid Fat Content) means the content (%) of solid fat present in fats and oils at a certain temperature. A sample to be measured is taken in a test tube for nuclear magnetic resonance (NMR) measurement, kept at 60°C for 30 minutes to completely melt the fat and oil, and kept at 0°C for 60 minutes to solidify it. After keeping this at a predetermined measurement temperature for 30 minutes, the SFC is measured by the NMR method.

The frozen dessert of this embodiment has a frozen dessert body and a coating layer made of an oil and fat composition.
The frozen dessert body is made of a frozen raw material mix. The composition of the frozen dessert body is the same as the composition of the raw material mix before freezing. The raw material mix constituting the frozen dessert body may be one type or two or more types.

[Raw material mix]
The raw materials for the raw material mix can be appropriately selected from known raw materials for frozen desserts, such as water, dairy products, carbohydrates, sweeteners, oils and fats, emulsifiers, stabilizers, acidulants, vegetable proteins, eggs, flavors, colorants, fruit juice, fruit pulp, dietary fiber, various food ingredients (alcoholic beverages, matcha, jam, chocolate), and other food additives.
Examples of sweeteners include sugars such as sugar (white sugar, granulated sugar, brown sugar, brown sugar, beet sugar), starch syrup, powdered syrup, mixed isomerized sugar, isomerized sugar, lactose, glucose, maltose, fructose, invert sugar, reduced malt syrup, honey, trehalose, palatinose, D-xylose, and the like; sugar alcohols such as xylitol, sorbitol, maltitol, erythritol, and the like; high-intensity sweeteners such as sodium saccharin, cyclamate and its salts, acesulfame potassium, thaumatin, aspartame, sucralose, alitame, neotame, and stevioside contained in stevia extract; etc. Sweeteners may be used alone or in combination of two or more kinds.
Examples of dairy products include raw milk, cow's milk, cream, butter, skim milk powder, concentrated skim milk, condensed milk, cheese, whey, whey protein concentrate, etc. One type of dairy product may be used alone, or two or more types may be used in combination.

The solid content is preferably 20 to 50% by mass, more preferably 30 to 40% by mass, based on the total mass of the raw material mix. If the solid content is equal to or higher than the lower limit of the above range, a smooth texture of the frozen dessert body can be obtained, and if the solid content is equal to or lower than the upper limit, the frozen dessert body can be prevented from melting excessively.
The fat content (fat content) is preferably 0.5 to 15.0% by mass, more preferably 5.0 to 13.0% by mass, based on the total mass of the raw material mix. If it is equal to or greater than the lower limit of the above range, the ice crystal feel of the ice cream portion is suppressed, making it easier to obtain a difference in texture from the oil and fat composition. If it is equal to or less than the upper limit, the oily feel of the frozen dessert portion is suppressed, making it easier to feel a difference in flavor between the frozen dessert portion and the oil and fat composition.
When the raw material mix contains a sweetener, the content of the sweetener is preferably more than 0 and not more than 30% by mass, more preferably 10 to 20% by mass, based on the total mass of the raw material mix. If the content is not more than the upper limit, the frozen dessert body can be prevented from melting excessively.
When the raw material mix contains a dairy product, the milk solids content is preferably 3.0 to 30.0% by mass, more preferably 10.0 to 25.0% by mass, based on the total mass of the raw material mix. If the content is equal to or higher than the lower limit of the above range, the ice cream portion is likely to have an appropriate overrun. If the content is equal to or lower than the upper limit, a good structure of the frozen dessert body is likely to be obtained.
The milk fat content is preferably more than 0 and not more than 15.0% by mass, more preferably 3.0 to 13.0% by mass, based on the total mass of the raw material mix. When the milk fat content is equal to or more than the lower limit of the above range, a good flavor derived from the milk fat is easily obtained, and when the milk fat content is equal to or less than the upper limit of the above range, a good texture of the frozen dessert body is easily obtained.

Preferred embodiments of the raw material mix include, for example, an embodiment containing moisture and a sweetener, and an embodiment containing moisture, a sweetener, and fat.
The freezing point of the raw material mix is preferably −7.0 to −0.5° C., more preferably −4.0 to −2.0° C. When the freezing point is equal to or higher than the lower limit of the above range, shape retention during filling is easily achieved. In addition, the frozen dessert body can be prevented from melting excessively. When the freezing point is equal to or lower than the upper limit, the frozen dessert body can be easily softened.

[Oil and fat composition]
The fat or oil contained in the fat or oil composition is not particularly limited as long as it is a fat or oil that can be used as a component of a coating layer of a frozen dessert. The fat or oil composition is, for example, chocolate.
Examples of fats and oils include rapeseed oil, soybean oil, sunflower seed oil, cottonseed oil, peanut oil, rice bran oil, corn oil, safflower oil, olive oil, palm oil, palm kernel oil, shea butter, sal butter, and cocoa butter.

The oil and fat composition may contain one type of oil or two or more types of oils and fats.
The content of the oil and fat relative to the total mass of the oil and fat composition is preferably 35 to 75 mass%, more preferably 40 to 70 mass%, and even more preferably 45 to 65 mass%. If it is equal to or more than the lower limit of the above range, the viscosity is prevented from becoming too high, causing a feeling in the mouth or a deterioration in texture, and the oil and fat composition alone does not remain after eating the frozen dessert, allowing the taste of both the frozen dessert itself and the oil and fat composition to be enjoyed. If it is equal to or less than the upper limit, it is difficult to have an oily flavor, and it is easy to prevent the coating layer from becoming thin and easily cracked.

The oil composition may contain other components in addition to the oil.
Examples of other ingredients include cocoa raw materials such as cocoa mass and cocoa powder; sweeteners: dairy products; water; emulsifiers; thickening stabilizers; salty agents such as salt and potassium chloride; acidulants such as acetic acid, lactic acid, gluconic acid; coloring agents such as β-carotene, caramel, and red koji pigment; antioxidants such as tocopherol and tea extract; plant proteins such as wheat protein and soy protein; egg products such as eggs and various egg products; flavorings; spices; seasonings; pH adjusters; food preservatives; shelf life enhancers; various food ingredients such as fruit, fruit juice, coffee raw materials, and nut and seed raw materials.
Specific examples of sweeteners and dairy products include the same sweeteners and dairy products as those used in the raw material mix.

The SFC (-10°C) of the oil and fat composition is 20 to 60%, preferably 25 to 55%, and more preferably 30 to 50%. If it is equal to or higher than the lower limit of the above range, the oil and fat composition can be prevented from melting excessively, and the oil and fat composition alone does not melt from the moment the frozen dessert is eaten, allowing the tastes of both the frozen dessert itself and the oil and fat composition to be enjoyed. If it is equal to or lower than the upper limit, the oil and fat composition is unlikely to melt excessively, and the oil and fat composition alone does not remain unmelted after eating the frozen dessert, allowing the tastes of both the frozen dessert itself and the oil and fat composition to be enjoyed.
The difference between SFC(-10°C)-SFC(20°C) of the oil and fat composition is 20 to 55%, and more preferably 25 to 50%. When the difference is equal to or greater than the lower limit of the above range, the oil and fat composition starts to melt after being put in the mouth and does not take an excessively long time to be consumed, so that the melting speed of the frozen dessert body matches that of the frozen dessert body, and the melting balance of the frozen dessert body and the oil and fat composition is good, whereas when the difference is equal to or less than the upper limit, the flavor of the oil and fat composition can be felt from the time of putting it in the mouth until the end of eating, and the melting speed of the frozen dessert body matches that of the frozen dessert body, so that the melting balance of the frozen dessert body and the oil and fat composition is good.
The difference between SFC(-10°C)-SFC(10°C) of the oil and fat composition is preferably 15% or more, and more preferably 15 to 40%. If it is equal to or more than the lower limit of the above range, the flavor of the oil and fat composition does not remain in the mouth for as long as the frozen dessert itself when the frozen dessert is eaten, and if it is equal to or less than the upper limit, the flavor of the oil and fat composition does not disappear before the frozen dessert itself when the frozen dessert is eaten.
The SFC of the oil and fat composition can be adjusted by the melting point and composition of the oil and fat contained in the oil and fat composition.

Preferred embodiments of the oil and fat composition include the following embodiments (1) to (3).
Aspect (1): An oil or fat composition having an SFC(-10°C) of 20 to 60%, an SFC(0°C) of 10 to 50%, an SFC(10°C) of 0 to 25%, an SFC(20°C) of 0 to 5%, an SFC(25°C) of 0%, a difference between SFC(-10°C) and SFC(20°C) of 20 to 55%, and a difference between SFC(-10°C) and SFC(10°C) of 15 to 50%.
Aspect (2): An oil or fat composition having an SFC(-10°C) of 25 to 55%, an SFC(0°C) of 10 to 45%, an SFC(10°C) of 0 to 20%, an SFC(20°C) of 0 to 5%, an SFC(25°C) of 0%, a difference between SFC(-10°C) and SFC(20°C) of 25 to 50%, and a difference between SFC(-10°C) and SFC(10°C) of 15 to 45%.
Aspect (3): An oil or fat composition having an SFC(-10°C) of 30 to 50%, an SFC(0°C) of 15 to 40%, an SFC(10°C) of 0 to 15%, an SFC(20°C) of 0 to 2%, an SFC(25°C) of 0%, a difference between SFC(-10°C) and SFC(20°C) of 30 to 50%, and a difference between SFC(-10°C) and SFC(10°C) of 25 to 35%.

<Frozen desserts>
The size and shape of the frozen dessert of this embodiment are not particularly limited. For example, a size that allows one piece to fit in the mouth is preferable. Specifically, the volume of the frozen dessert body is preferably 5 to 15 mL, more preferably 7 to 13 mL. Examples of the shape include a roughly columnar shape, a granular shape, a plate shape, a rod shape, and the like. Examples of the product shape are shown in FIG. 1.

The overrun (hereinafter sometimes referred to as OR) of the frozen dessert body is 5 to 60%, preferably 10 to 50%. If it is equal to or higher than the lower limit of the above range, the frozen dessert body can have suitable shape retention and melt-in-the-mouth feel, and if it is equal to or lower than the upper limit, a rich flavor can be obtained.
Overrun is the percentage value of the air volume contained in the frozen product (frozen dessert main body) of the raw material mix relative to the volume of the raw material mix before air is mixed in. For example, an overrun value of 100% means that the frozen product of the raw material mix contains the same volume of air as the raw material mix.

The ratio of the area of the portion covered by the coating layer to the entire outer surface of the frozen dessert body (hereinafter also referred to as the coverage rate) is 90 to 100%. From the viewpoint of improving the appearance of the product, 95 to 100% is more preferable, and 99 to 100% is even more preferable.

In the frozen dessert of this embodiment, the mass ratio of the frozen dessert body to the coating layer, that is, frozen dessert body:coating layer, is 3:1 to 6:1, preferably 3:1 to 5:1, and more preferably 4:1 to 5:1. When the ratio of the coating layer is equal to or greater than the lower limit of the above range, the entire outer surface of the frozen dessert body can be sufficiently covered, and when the ratio is equal to or less than the upper limit, the coating does not excessively cover the frozen dessert body.
The mass ratio of the frozen dessert body to the coating layer in the frozen dessert can be measured by the following method.
The coating layer is peeled off from the frozen dessert, and then the mass of the dessert body and the coating layer are measured to calculate the mass ratio.

<Method of manufacturing frozen desserts>
(Raw material mix preparation process)
First, a raw material mix is prepared. Preferably, all ingredients of the raw material mix are mixed to obtain a mixed liquid, which is then heat sterilized to obtain a raw material mix. Raw materials that are easily denatured by the heat during heat sterilization, such as flavorings, may be added after heat sterilization.
During mixing, the mixture may be heated to a temperature range in which the components do not deteriorate, for example, about 60 to 80° C. If necessary, the mixture may be filtered or homogenized before or after heat sterilization.
The heat sterilization device may be a plate type sterilizer, a tubular type sterilizer, an infusion type sterilizer, an injection type sterilizer, a batch type sterilizer, or the like.

(Freezing process)
Next, the raw material mix is cooled to near the freezing point while incorporating air to obtain a partially frozen product having fluidity. This step can be performed using a freezer known in the production of frozen desserts.
The overrun of the partially frozen material mix is the same as the overrun of the frozen product (the frozen dessert itself) produced by freezing the partially frozen material.

(Molding process)
Next, the partially frozen product is molded, cooled and solidified to obtain a frozen dessert body. This process can be carried out using a molding method known in the manufacture of frozen desserts. For example, the following methods (1) and (2) can be used as the molding method.
Method (1): A method in which the partially frozen product is filled into a mold of a desired shape, cooled and solidified, and then the frozen dessert body is removed from the mold. After being removed from the mold, it may be cut.
Method (2): A method in which the partially frozen product is cut and shaped while being discharged from an extrusion nozzle having an outlet of a desired shape, and the resulting shaped product is cooled and solidified.

In method (1), the temperature of the partially frozen composition immediately before filling into the mold is preferably within the range of the freezing point ±1°C, more preferably within the range of the freezing point ±0.5°C, and even more preferably within the range of (freezing point -0.2)°C to (freezing point -0.1)°C. If it is equal to or above the lower limit of the above range, the fluidity of the partially frozen composition is sufficiently high, it is easy to fill into the mold, and defects in the shape are unlikely to occur. If it is equal to or below the upper limit, the ice crystals in the frozen dessert body are likely to be small, a smooth texture is likely to be obtained, and a good balance between the texture of the coating layer and the texture of the frozen dessert body is likely to be obtained.

In method (2), the temperature of the partially frozen composition immediately before being fed to the extrusion nozzle is preferably in the range of (freezing point -10)°C to the freezing point, more preferably in the range of (freezing point -7)°C to (freezing point -1)°C, and even more preferably in the range of (freezing point -4)°C to (freezing point -2)°C. If the temperature is equal to or higher than the lower limit of the above range, a good structure is likely to be obtained. If the temperature is equal to or lower than the upper limit, the shape stability of the molded product is excellent.

The temperature conditions for solidifying the partially frozen product in the mold in method (1) and for solidifying the molded product in method (2) are preferably such that the surface temperature is cooled to (freezing point -2)°C or lower and the center temperature is cooled to (freezing point -5)°C or lower.
It is more preferable to cool the frozen dessert so that the surface temperature is below (freezing point - 5) °C and the central temperature is below (freezing point - 7) °C, as this makes it easier to prevent the transfer of moisture from the frozen dessert body to the coating layer.

(Coating process)
Next, a coating layer is formed so as to cover the outer surface of the frozen dessert body to obtain the frozen dessert.
Specifically, the outer surface of the frozen dessert body is coated with a coating liquid comprising an oil and fat composition, and then the coating liquid is cooled and hardened to form a coating layer.
The coating method may be a method known in the art for producing frozen desserts, such as a dipping method or an enrobing method.
In the dipping method, the frozen dessert body is immersed in a coating liquid, pulled out, and cooled to harden the coating liquid and form a coating layer.
In the enrobing method, a coating liquid is poured onto the frozen dessert body to cover it, and then the coating liquid is cooled and hardened to form a coating layer.

The liquid temperature (T°C) of the coating liquid is preferably 25 to 50°C, more preferably 30 to 40°C. If it is equal to or higher than the lower limit of the above range, it is easy to stably obtain an appropriate viscosity of the coating liquid. If it is equal to or lower than the upper limit, it is easy to suppress the transfer of moisture from the frozen dessert body to the coating layer, and it is easy to suppress the increase of ice crystals due to melting of the frozen dessert body.

The viscosity of the coating liquid at T° C. is preferably from 250 to 550 mPa·s, more preferably from 300 to 500 mPa·s, and even more preferably from 350 to 450 mPa·s.
If the amount is equal to or greater than the lower limit of the above range, a sufficient amount of coating can be achieved for the frozen dessert body, whereas if the amount is equal to or less than the upper limit, excessive coating can be prevented.

In the coating process, the coating conditions are adjusted so that the coverage is 90 to 100%. For example, if the coverage is insufficient, the amount of the coating layer is increased.
The coating conditions are adjusted so that the mass ratio of the frozen dessert body to the coating layer falls within the above range. For example, the mass of the coating layer can be adjusted by the coating time and the temperature of the coating liquid.
The coverage rate in frozen desserts can be measured by the following method.
In a frozen dessert whose outer surface is covered with a coating layer, the exposed area of the frozen dessert body is visually confirmed, and its area is analyzed using image analysis software (Image J).
Specifically, each frozen dessert is photographed and the photographed image is converted into a black and white 16-bit image. After that, threshold processing is performed to create an appropriate binary image in Black & White mode (white: frozen dessert body, black: coating layer). The number of white (0) and black (255) dots is counted in the binary image using a histogram function, and the white area ratio (= white count number ÷ (black count number + white count number) × 100) is calculated. The ratio of the area where the frozen dessert body is not exposed to the entire surface area of the frozen dessert is defined as the coverage rate.
In addition, if the colors of the frozen dessert itself and the coating layer are similar, an appropriate binary image can be obtained by first filling in the areas in the image where the frozen dessert itself is exposed with white.

The present invention will be described in more detail below using examples, but the present invention is not limited to these examples.

<Sensory evaluation method>
A frozen dessert having a body of frozen dessert (hereinafter also referred to as ice cream) covered with an oil and fat composition (hereinafter also referred to as chocolate) was subjected to a sensory evaluation by the following method.
Seven panelists with at least one year of experience in developing frozen desserts tasted the frozen dessert samples (surface temperature -15°C, center temperature -20°C) and, while chewing, rated them in three categories: (1) balance of melt-in-the-mouth texture, (2) balance of flavor, and (3) richness of flavor, using the following criteria.
For each item, the seven panelists calculated an average score and rated it on a four-point scale based on the following criteria.
Each panelist placed one frozen dessert sample in their mouth, waited until the sample cooled, and then began chewing to evaluate the dessert. In addition, the panelists tasted a reference sample before the evaluation to calibrate the scale between the evaluators.
"(1) Balance of melting speed" was defined as "the degree of difference in the speed at which chocolate and ice cream melt in the mouth."
"(2) Taste balance" was defined as "the degree of difference in the intensity of the taste of the chocolate and ice cream from the moment you start eating until you swallow it."
"(3) Richness of flavor" was defined as "the degree of richness of the flavor of the chocolate and ice cream from the moment you start eating until you swallow it."
[Scoring criteria]
(1) Balance of melting in the mouth 1 point: Extremely poor balance (either the ice cream or the chocolate melts quickly, or one of them remains in the mouth for a long time).
2 points: Imbalanced (either the ice cream or the chocolate melts first, or one remains in the mouth).
3 points: Not well balanced, but acceptable.
4 points: Well balanced (the ice cream and chocolate melt at roughly the same speed, though not at the same time, so neither sticks around for long).
5 points: Perfect balance (ice cream and chocolate melt at the same time).
(2) Taste balance 1 point: Extremely poor balance (one of the flavors disappears quickly or lingers for a long time).
2 points: Poor balance (one of the flavors disappears first or remains).
3 points: Not well balanced, but acceptable.
4 points: Well balanced (the ice cream and chocolate flavors linger equally, though not simultaneously, and neither flavor lingers for long).
5 points: Extremely well-balanced (the ice cream and chocolate flavors are felt and disappear at the same time).
(3) Richness of flavor: 1 point: Both the ice cream and chocolate melted too quickly in the mouth, making the flavor very weak.
2 points: The ice cream or chocolate melts too quickly and the flavor is not rich.
3 points: Either the ice cream or chocolate lingers strongly in the mouth, giving it a rich taste.
4 points: Both the ice cream and chocolate linger in the mouth for a relatively long time and have a strong, rich flavor.
5 points: Both the ice cream and chocolate remain firmly in the mouth, and the flavor is extremely rich.
[Scoring criteria]
◎: Average score is 3.5 or above.
○: Average score is 3.0 or more and less than 3.5.
△: Average score is 2.5 or more and less than 3.0 points.
×: Average score is less than 2.5 points.

<Resistance to temperature changes>
The frozen dessert samples were stored in a -25°C freezer for 48 to 72 hours to adjust the temperature, and then transferred to a room temperature (25 to 26°C) atmosphere and allowed to stand. The time when the samples were taken out of the freezer was defined as the starting time, and the time (retention time) until the ice cream started to leak from the coating layer (chocolate) was measured.
The retention time was measured three times and the average value was calculated. Evaluation was made on a four-level scale based on the following evaluation criteria. The longer the retention time, the better the appearance retention against changes in environmental temperature, such as when the product is brought home at room temperature.
[Evaluation criteria]
◎: The average retention time is 25 minutes or more.
◯: The average retention time is 20 minutes or more and less than 25 minutes.
Δ: The average retention time is 15 minutes or more and less than 20 minutes.
×: The average retention time is less than 15 minutes.

<Vibration resistance>
The frozen dessert samples were stored in a -25°C freezer for 48-72 hours to adjust the temperature (surface temperature -20°C, center temperature -25°C), and then transferred to a room temperature (25-26°C) atmosphere and immediately placed in a plastic centrifuge tube (inner diameter 33 mm, length 100 mm). The bottom of the centrifuge tube was placed in contact with a vortex mixer (product name TUBE MIXER TRIO HM-1F, AS ONE Corporation), the scale was set to 10 (2500 rpm), and the sample was shaken for 30 seconds and then removed. The state of cracks in the coating layer (chocolate) was visually observed and evaluated according to the following criteria. Evaluation was performed on three frozen desserts, and an overall evaluation was performed based on the results according to the following criteria.
[Evaluation criteria]
◎: No cracks.
△: There are inconspicuous cracks.
×: Obvious cracks are present. The cracks are present only in the corners, and not on the surface.
××: There are obvious cracks. There are cracks on the surface.
[Overall evaluation]
◎: Three test results were ◎.
○: Two test results are excellent.
△: Two or more test results are △.
×: Two or more test results are ×.
XX: Two or more test results are XX.

<Ingredients for frozen dessert>
Unsalted butter: manufactured by Morinaga Milk Industry Co., Ltd., milk fat content 83.0% by mass, non-fat milk solids content 1.4% by mass, solids content 84.4% by mass.
Skim milk powder: manufactured by Morinaga Milk Industry Co., Ltd., milk fat content 1.0% by mass, non-fat milk solids content 95.2% by mass, solids content 96.2% by mass.
Beet sugar: Hokkaido Sugar Industry Co., Ltd. product name, beet granulated sugar, solids content 100% by mass.
Powdered candy: Showa Sangyo Co., Ltd. product name, K-SPD, solid content 96% by mass.
Stabilizer: Taiyo Kagaku Co., Ltd., locust bean gum 45.0% by mass, guar gum 45.0% by mass, carrageenan 10.0% by mass.
Emulsifier: manufactured by Riken Vitamin Co., Ltd., glycerin fatty acid ester 99.99% by mass, phosphoric acid 0.01% by mass.

(Preparation Example 1: Preparation of frozen dessert body)
All the raw materials shown in Table 1 were mixed and dissolved by stirring at 70° C. for 20 minutes, and then homogenized. Then, the mixture was sterilized by heating at 90° C. for 15 seconds and cooled to 5° C. to obtain a raw material mix.
The obtained raw material mix was fed to a continuous freezer, and the partially frozen product discharged from the continuous freezer was filled into a plate-shaped mold having a thickness of 18 mm. This was cooled at -35°C for 24 hours to solidify. The plate-shaped solidified product was removed from the mold and cut into a rectangular parallelepiped shape having a length of 23 mm, a width of 23 mm, and a height of 18 mm to obtain a frozen dessert main body.
The overrun (set value) of the partially frozen product discharged from the continuous freezer was changed to 0%, 10%, 30%, 50%, and 80%, and the frozen dessert body was prepared.

(Preparation Example 2: Preparation of oil and fat composition)
The following chocolates A to D, which have different fat and oil compositions but the same flavor, were prepared and their SFC was measured. The measurement results are shown in Table 2 and Figure 2. In the graph of Figure 2, the horizontal axis represents temperature and the vertical axis represents SFC (unit: %).
Chocolate A: 100% soybean oil by mass.
Chocolate B: Palm superolein 68% by mass, soybean oil 23% by mass, palm olein 9% by mass.
Chocolate C: Palm superolein 58% by mass, coconut oil 27% by mass, soybean oil 15% by mass.
Chocolate D: Palm olein 53% by mass, coconut oil 36% by mass, soybean oil 11% by mass.

(Production Example 1: Production of frozen dessert)
Five types of frozen dessert bodies with different overruns prepared in Preparation Example 1 were coated with coating layers made of chocolates A to D to produce 20 types of frozen desserts.
Specifically, the chocolate was heated and melted, and the frozen dessert body with the skewer-shaped pick inserted was dipped into a bath of melted chocolate to coat the entire outer surface of the frozen dessert body. The temperature of the melted chocolate (coating liquid) was set to 30 to 40°C and the viscosity (using a B-type viscometer with rotor No. 2, at 12 rpm) to 250 to 550 mPa·s.
The amount of chocolate applied was 2 g per frozen dessert body. The mass ratio of frozen dessert body to coating layer taking into account overrun is shown in Table 3.
The frozen dessert was coated with chocolate and then cooled at -25°C for 48 hours to solidify the coating layer, thereby obtaining a frozen dessert. The coating rate was 99% or more.

(evaluation)
The resulting frozen desserts were subjected to a sensory evaluation using the above-mentioned method for (1) balance of melting in the mouth, (2) balance of flavor, and (3) richness of flavor. The results of the evaluation by seven panelists are shown in Table 4.
For each evaluation item, the average scores of the seven panelists are shown in Table 5, and the results of a four-level evaluation based on the average scores are shown in Table 8.

The resulting frozen desserts were evaluated for their resistance to temperature changes using the method described above. The average retention times are shown in Table 6, and the results of a four-level evaluation based on the average values are shown in Table 8.

The obtained frozen desserts were evaluated for their resistance to vibration using the method described above. The test was performed three times. The results of the three tests are shown in Table 7, and the overall evaluation results are shown in Table 8.

As shown in the results in Tables 2 and 8, when chocolate B or C, which has an SFC (-10°C) of 20-60% and a difference in SFC (-10°C) - SFC (20°C) of 20-55%, is used as the fat composition (chocolate) constituting the coating layer, and the overrun of the frozen dessert body (ice cream) is set to 5-60%, a frozen dessert is obtained that has an excellent balance of melting in the mouth, flavor balance, and richness of flavor when the frozen dessert body and coating layer are eaten together, as well as excellent resistance to temperature changes and vibration.

Claims (4)

A frozen dessert body and a coating layer made of an oil and fat composition,
90 to 100% of the outer surface of the frozen dessert body is covered with the coating layer,
The mass ratio of the frozen dessert body to the coating layer is 3:1 to 6:1;
The overrun of the frozen dessert body is 5 to 60%,
The frozen dessert has an SFC (solid fat content) of the oil and fat composition at -10°C of 20 to 60%, and the difference obtained by subtracting the SFC at 20°C from the SFC at -10°C is 20 to 55%. The frozen dessert according to claim 1, wherein the difference between the SFC at -10°C and the SFC at 10°C of the oil and fat composition is 15% or more. The method includes the steps of cooling the raw material mix while incorporating air to obtain a partially frozen product having an overrun of 5 to 60%, shaping the partially frozen product, cooling and solidifying it to obtain a frozen dessert body, covering 90 to 100% of the outer surface of the frozen dessert body with a coating liquid comprising an oil and fat composition, and cooling and hardening the coating liquid to form a coating layer to obtain the frozen dessert,
As the oil and fat composition, an oil and fat composition having an SFC (solid fat content) at -10°C of 20 to 60% and a difference obtained by subtracting the SFC at 20°C from the SFC at -10°C of 20 to 55% is used,
The method for producing a frozen dessert, wherein the mass ratio of the frozen dessert body to the coating layer is 3:1 to 6:1. The method for producing frozen desserts according to claim 3, wherein the temperature of the coating liquid is T°C (25≦T≦50) and the viscosity of the coating liquid at T°C is 250 to 550 mPa·s.

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