JP7578617B2 - Mix for fried food, method for producing fried food using the same, and method for improving the texture of fried food - Google Patents

Description

The present invention relates to a mix for fried foods, which is used in the production of fried foods and contains specific water-soluble dietary fiber.

Fried foods are foods that are obtained by frying the object in oil, that is, by cooking it in oil that is hotter than the boiling point of water. Examples include fried snacks such as donuts and deep-fried foods such as tempura. Frying not only heats the object to cook it through, but also has the effect of evaporating the moisture in the object at high temperatures, allowing the oil to be absorbed into the air gaps where there was moisture. For this reason, fried foods (or the batter in the case of deep-fried foods) are characterized by their crispy texture.

Regarding improved technology for fried foods, for example, Patent Document 1 describes a doughnut mix suitable for producing frozen doughnuts that can be eaten in a frozen state, which contains a first component that is a sugar such as dextrin, and a second component that is an oil absorption inhibitor such as water-soluble dietary fiber. The technical idea of Patent Document 1 is to improve the eatability of the doughnut in a frozen state by using a relatively large amount of the first component, and to suppress inconveniences such as excess oil caused by using a large amount of the first component by using the second component in combination.

Patent Document 2 describes the use of low-carbohydrate food ingredients such as resistant dextrin in fried foods such as donuts in response to the recent trend toward health. Patent Document 3 describes that by adding isomaltodextrin to snack foods such as potato chips, water drainage during the production of the snack foods is improved, resulting in snack foods with a crispy texture.

JP 2018-57299 A JP 2017-55662 A JP 2018-201371 A

The unique crispy texture of fried foods is easily lost over time due to the influence of moisture in the fried food or in the surrounding environment. For example, when fried foods such as donuts and corn hot dogs are manufactured and sold at stores, even if the fried foods have a crispy texture immediately after they are manufactured and put on the shelves, the crispness may decrease over time, and by the time a consumer who purchased the fried food at the store takes it home to eat, the crispness may be completely lost and the fried food may become limp. No effective technology has yet been provided that can solve the problem of the loss of crispness in fried foods over time.

The objective of the present invention is to provide a technology capable of producing fried foods that can maintain a crispy texture for a long period of time.

The present invention relates to a mix for fried foods, which contains 0.5 to 15 mass % of high Tg water-soluble dietary fiber having a glass transition point of 180° C. or higher.
The present invention also relates to a method for producing fried foods using the mix for fried foods of the present invention.
The present invention also relates to a method for improving the texture of fried foods, which comprises adding 0.5 to 15 mass % of high Tg water-soluble dietary fiber having a glass transition point of 180° C. or higher to the fried food.

The mix for fried foods of the present invention (hereinafter simply referred to as the "mix") is characterized in that it contains 0.5 to 15 mass% of high Tg water-soluble dietary fiber having a glass transition temperature (Tg) of 180°C or higher. As is well known, Tg is the temperature at which a transition (glass transition) occurs between a hard glass state and a soft rubber state. In the present invention, by making water-soluble dietary fiber with a relatively high Tg of 180°C or higher (high Tg water-soluble dietary fiber) an essential component of the mix, fried foods produced using the mix (the coating part in the case of fried foods) are less likely to transition to a rubber state, and a crispy texture can be maintained for a long time. If the content of high Tg water-soluble dietary fiber in the mix is less than 0.5 mass%, the desired effect of the present invention is not achieved (see Comparative Example 6), and if the content exceeds 15 mass%, unintended cracks may occur in the fried food, resulting in a deterioration in appearance (see Comparative Example 7).

Tg can be measured using a differential scanning calorimeter (DSC). Specifically, for example, it can be measured by the following method.
A sample of the object to be measured (e.g., dietary fiber) is used in an amorphous state. Note that, before this measurement, the sample is heated once and then cooled to erase the thermal history of the sample. If the sample is in a crystalline state, the sample is heated once in the crystalline state to melt it, and then rapidly cooled before use. The Tg of the sample is measured using DSC. An example of the measurement conditions is shown below.
<Example of measurement conditions for DSC measurement>
A sample (6 mg) was sealed in a pressure-resistant pan and set in a DSC (DSC6100; SII). Alumina was used as the reference material. Measurements were performed in the temperature range of 20 to 230°C at a heating rate of 5°C/min. After heating to a constant temperature (1st scan), the sample was cooled to 20°C and heated again (2nd scan). The results were analyzed using the software provided with the DSC (Thermal Analysis Software TA7000 (Hitachi High-Tech Science)).

The Tg of the high Tg water-soluble dietary fiber used in the present invention is 180°C or higher, preferably 190°C or higher. There is no particular upper limit to the Tg of the high Tg water-soluble dietary fiber, but it is preferably 230°C or lower, more preferably 215°C or lower.

The content of high Tg water-soluble dietary fiber in the mix of the present invention is 0.5 to 15% by mass, preferably 1 to 10% by mass, and more preferably 3 to 10% by mass, based on the total mass of the mix, from the viewpoint of achieving a high degree of compatibility between crispness and appearance of the fried food.

As described above, the mix of the present invention contains a substance with a Tg of 180°C or higher in order to make fried foods produced using the mix less likely to transition to a rubbery state, and water-soluble dietary fiber is used as the high Tg substance. The high Tg water-soluble dietary fiber used in the present invention is typically a polysaccharide, but starches, which are also polysaccharides, generally tend to have a higher Tg than water-soluble dietary fibers, so it is possible to use starches as the high Tg substance to be contained in the mix in order to achieve the above-mentioned purpose. However, as a result of various studies by the inventors, it was found that when starches are contained as high Tg substances in a mix for fried foods, the fried foods produced using the mix have relatively strong moisture retention properties and therefore tend to absorb moisture from the surrounding environment, making it difficult to achieve the desired effects of the present invention. Therefore, in the present invention, water-soluble dietary fiber is used as the high Tg substance.

Examples of the high Tg water-soluble dietary fiber used in the present invention include, for example, indigestible dextrin with a high Tg, and particularly preferably isomaltodextrin. At present, it is not clear whether all substances called isomaltodextrin can be used as high Tg water-soluble dietary fiber in the present invention, but an example of isomaltodextrin that can be used in the present invention is described in [0015] to [0018] of Patent Document 3 (JP Patent Publication 2018-201371).
Examples of high Tg water-soluble dietary fibers include, but are not limited to, Fibersol 2 (Matsutani Chemical Industry Co., Ltd.) and Fiberixa (Hayashibara Co., Ltd.), which is isomaltodextrin.

The mix of the present invention preferably contains sugars in addition to the high Tg water-soluble dietary fiber. This can further improve the texture (crispyness) of fried foods produced using the mix. In addition, the "sugars" in the present invention do not include dietary fibers such as high Tg water-soluble dietary fiber and low Tg water-soluble dietary fiber described later. Examples of sugars include monosaccharides such as glucose, fructose, xylose, and galactose; disaccharides such as sucrose, maltose, lactose, and trehalose; and sugar alcohols such as xylitol, sorbitol, and lactitol. These can be used alone or in combination of two or more. Preferably, monosaccharides and/or disaccharides are used as sugars, and the total amount of monosaccharides and disaccharides among the sugars used is 80% by mass or more. Also, preferably, sucrose is used as sugar, and 50% by mass or more of the sugars used is used.

In the mix of the present invention, the mass ratio of sugars to high Tg water-soluble dietary fiber is preferably 1:0.01 to 1:2, more preferably 1:0.03 to 1:1, and even more preferably 1:0.1 to 1:0.5, in terms of the balance between improving the crispness of the fried food and the taste and appearance. That is, the mix of the present invention preferably contains 1 to 200 parts by mass, more preferably 13 to 100 parts by mass, and even more preferably 10 to 50 parts by mass of high Tg water-soluble dietary fiber per 100 parts by mass of sugars in the mix.

In addition, the sugar content in the mix of the present invention is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, based on the total mass of the mix, from the viewpoint of the taste and appearance of the fried food. In addition, the upper limit of the sugar content in the mix of the present invention is not particularly limited, but is preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 40% by mass or less, from the viewpoint of the taste and appearance of the fried food.

In addition, the total content of sugars and high Tg water-soluble dietary fiber in the mix of the present invention is, from the viewpoint of the taste and appearance of the fried food, preferably 10 to 50% by mass, more preferably 15 to 45% by mass, and even more preferably 20 to 40% by mass, relative to the total mass of the mix.

The mix of the present invention preferably contains, in addition to the high Tg water-soluble dietary fiber and, if necessary, sugar, a low Tg water-soluble dietary fiber having a glass transition point of 125°C or more and less than 180°C. By using high Tg water-soluble dietary fiber and low Tg water-soluble dietary fiber in combination as components of the mix, the texture (crispy), shape retention, appearance, and other properties of fried foods can be improved to an even higher level. The Tg of the low Tg water-soluble dietary fiber used in the present invention is preferably 125°C or more and 150°C or less.

Examples of the low Tg water-soluble dietary fiber used in the present invention include inulin, resistant dextrins with low Tg such as resistant glucan, and the like, and these can be used alone or in combination of two or more. Among these, inulin is particularly preferred from the viewpoint of improving the crispness of fried foods.

When low Tg water-soluble dietary fiber is contained in the mix of the present invention, the total content of the low Tg water-soluble dietary fiber and the high Tg water-soluble dietary fiber is, from the viewpoint of the taste and appearance of the fried food, preferably 20% by mass or less, more preferably 15% by mass or less, and even more preferably 10% by mass or less, based on the total mass of the mix.

The mix of the present invention may contain ingredients other than the above-mentioned ingredients (high Tg water-soluble dietary fiber, low Tg water-soluble dietary fiber, sugars). Other ingredients include cereal flours. Examples of cereal flours that can be contained in the mix of the present invention include flours such as strong flour, semi-strong flour, medium-strength flour, weak flour, and durum wheat flour, rye flour, corn flour, barley flour, buckwheat flour, soy flour, pearl barley flour, and millet flour; starches (unprocessed starches) such as tapioca starch, potato starch, corn starch, waxy corn starch, and wheat starch, and processed starches obtained by subjecting these unprocessed starches to one or more treatments such as oil processing, gelatinization, etherification, esterification, crosslinking, and oxidation. These may be used alone or in combination of two or more.

When the mix of the present invention contains cereal flour, the content of cereal flour in the mix is preferably 45 to 75% by mass, more preferably 50 to 70% by mass, relative to the total mass of the mix.

The mix of the present invention may contain ingredients other than the above-mentioned grain flours, and these can be appropriately selected depending on the type of fried food in which the mix is used. Specific examples include emulsifiers such as glycerin fatty acid esters, sucrose fatty acid esters, sorbitan fatty acid esters, propylene glycol fatty acid esters, lecithin, organic acid monoglycerides, sodium stearoyl lactylate, and calcium stearoyl lactylate; protein materials such as gluten, gliadin, and glutenin (all wheat proteins), whole eggs, egg whites, and egg yolks (all egg proteins), skimmed milk powder, whey protein (all milk proteins), soy protein, and gelatin; fats and oils such as animal fats and oils, and vegetable fats and oils; salt, powdered soy sauce, fermented products such as fermented products derived from fruits, powdered miso paste, amino acids, and other seasonings; dried eggs such as egg powder, thickening polysaccharides, leavening agents, milk ingredients, flavorings, enzymes, and colorings, and these can be used alone or in combination of two or more. The content of ingredients other than cereal flour in the mix of the present invention is preferably 20 mass % or less based on the total mass of the mix.

The mix of the present invention is obtained by mixing the above-mentioned components including the high Tg water-soluble dietary fiber. The mix of the present invention is in the form of a powder, granules, or other powder at room temperature and pressure.

The mix of the present invention can be applied to various fried foods, specifically, for example, fried confectionery or bakery foods such as donuts; batter mix or blender mix for fried foods such as corn dogs, tempura, fries, karaage, and fritters. Fried foods for which the mix of the present invention is particularly suitable include donuts, corn dogs, karinto, and deep-fried pies, more preferably donuts and corn dogs. The mix of the present invention is particularly suitable for cake donuts, and is particularly suitable for old-fashioned donuts. Old-fashioned donuts are donuts that have cracks on one side (top) and have a unique crispy texture.

The mix of the present invention can be used in the same manner as other mixes of this type in the production of fried foods. Typically, a liquid is added to the mix of the present invention to prepare a clay-like dough (so-called dough) or a liquid or paste-like dough (so-called batter), and the dough is fried to produce the desired fried food. Examples of liquids to be mixed with the mix include aqueous liquids containing water, oil, seasonings, egg liquid, milk, etc. The mixing ratio of the mix to the liquid is generally about 1:0.2 to 1:8 in terms of mix:liquid.

A method for producing donuts using the mix of the present invention typically includes the steps of adding a liquid such as water to the mix to prepare a dough (dough or batter), and then putting the dough into heated oil to fry. A method for producing fried foods using the mix of the present invention typically includes the steps of adding a liquid such as water to the mix to prepare a dough (batter), adhering the dough to the surface of an ingredient, and then putting the ingredient with the dough into heated oil to fry.

The present invention includes a method for improving the texture of fried foods, which comprises adding 0.5 to 15% by mass, preferably 1 to 10% by mass, and more preferably 3 to 10% by mass, of high Tg water-soluble dietary fiber having a glass transition point of 180°C or higher to the fried food. Unless otherwise specified, the above-mentioned description of the mix of the present invention and its production method are appropriately applied to the method for improving the texture of fried foods of the present invention. According to the method for improving the texture of fried foods of the present invention, the durability of the crispy texture of the fried food over time is improved, and the crispy texture can be maintained for a long time. When the fried food is a fried confectionery such as a donut or a bakery food, the fried food is typically produced by frying a dough containing high Tg water-soluble dietary fiber, and the high Tg water-soluble dietary fiber is contained throughout the fried food. On the other hand, when the fried food is a deep-fried food such as a corn hot dog, the fried food typically comprises an ingredient and a batter that covers the surface of the ingredient, and the high Tg water-soluble dietary fiber is contained in the batter.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples. Examples 1 and 9 are reference examples.

[Examples 1 to 8, Comparative Examples 1 to 7, Reference Example 1]
A doughnut mix was produced by mixing the ingredients according to the formulations in Tables 1 and 2 below. The details of the ingredients used are as follows. The mix of Reference Example 1 is a typical mix for old-fashioned doughnuts.
・Wheat flour: Weak flour (manufactured by Nisshin Flour Milling Co., Ltd., product name "Flower")
・Sugars (non-dietary fiber): maltodextrin (Tg 160℃)
Water-soluble dietary fiber A: Indigestible dextrin (Fibersol 2, Matsutani Chemical Industry Co., Ltd., Tg 185°C)
Water-soluble dietary fiber B: isomaltodextrin (Fibrixa, Hayashibara Co., Ltd., Tg 197°C)
Water-soluble dietary fiber C: Indigestible glucan (Fit Fiber, Nippon Shokuhin Kako Co., Ltd., Tg 128°C)
・ Water-soluble dietary fiber D: inulin (Tg 130°C)

[Test Example 1]
Using the doughnut mixes of each Example, Comparative Example, and Reference Example, old-fashioned doughnuts were produced by the following method. After production, the doughnuts were stored in an environment with an atmospheric temperature of 25° C. and a humidity of 50% for 15 hours, and then 10 expert panelists tasted them and evaluated the texture (crispyness) and the appearance (degree of cracking) according to the following evaluation criteria. The results are shown in Tables 1 and 2 below as the average evaluation points of the 10 panelists.

(Manufacturing old fashioned donuts)
72 g of water, 40 g of eggs, and 40 g of salad oil were added to 400 g of doughnut mix, and the mixture was stirred and mixed to prepare dough at a product temperature of 20° C. 40 g per doughnut was cut out from the dough using a doughnut cutter, and the dough was dropped into a fryer heated to 180° C. to fry one side of the dough, and after 1 minute, the dough was turned over and the other side was fryed to obtain the desired old-fashioned doughnut.

<Evaluation criteria for doughnut texture>
5 points: Very crispy, crumbly, extremely good.
4 points: Crispy and good.
3 points: slightly crispy.
2 points: Almost no crispness, a little flexible, and poor quality.
1 point: No crispness at all, flexible, extremely poor.
<Evaluation criteria for donut appearance>
5 points: No cracks on the back side of the donut, no cracks at all, extremely good.
4 points: Good condition with only slight cracks on the back in some places.
3 points: Some cracks on the back.
2 points: The reverse side is cracked all over and the circular shape cannot be maintained; defective.
1 point: The reverse side is cracked all over and the fabric is completely separated, extremely poor quality.

As shown in Table 1, the mixes of each Example contained high Tg water-soluble dietary fiber (water-soluble dietary fiber A or B) with a glass transition point of 180°C or higher, and therefore the texture of the donuts 15 hours after frying was superior to that of the Comparative Examples and Reference Examples which did not meet this requirement.
As shown in Table 2, the mixes of each Example had a high Tg water-soluble dietary fiber (water-soluble dietary fiber A or B) content of 0.5 to 15 mass %, and therefore the texture and/or appearance of the donuts 15 hours after frying was superior to that of the comparative examples which did not meet this requirement.

[Examples 9 to 14, Comparative Examples 8 to 11, Reference Example 2]
The ingredients were mixed according to the composition shown in Table 3 below to produce a mix for corn dogs. The details of the ingredients used were the same as those in the above-mentioned mix for donuts. The mix of Reference Example 2 is a typical mix for corn dogs.

[Test Example 2]
Using the mixes for corn dogs of each Example, Comparative Example, and Reference Example, corn dogs were produced by the following method. After production, the corn dogs were once frozen, and the frozen corn dogs were naturally thawed, and then re-fried for 4 minutes in refined soybean oil heated to 170 to 180°C. The corn dogs after re-fried were stored for 5 hours in an environment with an atmospheric temperature of 25°C and a humidity of 50%, and then eaten by 10 expert panelists, who evaluated the texture of the batter (crispyness, melting in the mouth) according to the following evaluation criteria, and the appearance of the batter (volume, smoothness of the surface) according to the following evaluation criteria. The results are shown in Table 3 below as the average evaluation points of the 10 panelists.

(Manufacturing corn dogs)
725 g of water and 1 kg of corn dog mix were put into a Hobart mixer and stirred at low speed with a beater for 1 minute to prepare a batter. A sausage (length 10 cm, weight 40 g) was pierced along the long axis on a skewer, and the prepared batter was applied to the surface of the sausage so that the weight after frying (product weight) was about 100 g, and then the sausage was fried for 4 minutes in soybean oil heated to 170 to 180°C to obtain the desired corn dog.

<Evaluation criteria for the texture of corn dog batter>
5 points: Crispy, melts in the mouth easily, extremely good.
4 points: Crispy, but not very melt-in-the-mouth. Good.
3 points: Crispy but not very melt-in-the-mouth.
2 points: No crispness, poor melting in the mouth, and remains somewhat lumpy in the mouth, poor quality.
1 point: No crispness, remains in the mouth like a dumpling, extremely poor quality.
<Evaluation criteria for the appearance of corn dog coating>
5 points: Large volume, smooth surface, extremely good.
4 points: The volume is somewhat large, the surface is almost smooth, and it is in good condition.
3 points: Medium volume, almost no cracks.
2 points: The volume is slightly small, there are some cracks on the surface, and it is defective.
1 point: The volume is small, or the surface is cracked or uneven, and the shape is unstable. Extremely poor.

As shown in Table 3, the mixes of each embodiment contained 0.5 to 15 mass% high Tg water-soluble dietary fiber (water-soluble dietary fiber A or B) with a glass transition point of 180°C or higher, and therefore had a superior texture and appearance of the corn dog coating 5 hours after frying compared to the comparative examples and reference examples which did not meet this requirement.

The present invention provides fried foods that can maintain a crispy texture for a long period of time.

Claims (6)

The mix for fried foods contains 0.5 to 15 mass % of a high Tg water-soluble dietary fiber having a glass transition point of 180° C. or higher, the high Tg water-soluble dietary fiber being isomaltodextrin . The mix for fried foods according to claim 1 further contains sugars, and the mass ratio of the sugars to the high Tg water-soluble dietary fiber is 1:0.01 to 1:2. The mix for fried foods according to claim 1 or 2 further contains low Tg water-soluble dietary fiber having a glass transition point of 125°C or more and less than 180°C, and the total content of the low Tg water-soluble dietary fiber and the high Tg water-soluble dietary fiber is 20 mass% or less. The mix for fried food according to any one of claims 1 to 3, wherein the fried food is a doughnut or a corn dog. A method for producing fried foods using the mix for fried foods described in any one of claims 1 to 4. A method for improving the texture of fried food, comprising adding 0.5 to 15 mass % of a high Tg water-soluble dietary fiber having a glass transition point of 180° C. or higher to the fried food, the high Tg water-soluble dietary fiber being isomaltodextrin .