Shumai skin for frozen shumai, frozen shumai and its manufacturing method

Abstract

The present invention provides a frozen shumai skin containing a water-soluble cellulose ether, a phospholipid, and citric acid. Preferably, the pH of the frozen shumai skin is 5.9 or less. The present invention also provides a frozen shumai skin containing a water-soluble cellulose ether and a phospholipid, and having a pH of 5.9 or less. Preferably, the water-soluble cellulose ether comprises hydroxypropyl methylcellulose and / or methylcellulose.

Description

[Technical Field]

[0001] The present disclosure relates to shumai skin for frozen shumai, frozen shumai, and a method for producing the same. [Background technology]

[0002] Although frozen foods have the advantages of extending their shelf life, improving food safety, and allowing them to be consumed regardless of the season or region, they also have many limitations and drawbacks.

[0003] For example, Patent Document 1 describes a microwave-safe, frozen steamed, bean-jam-filled food product that includes a noodle sheet food and a batter, the batter containing water in an amount of 70% by weight or more based on the total weight of the batter. Patent Document 1 also describes that, according to the invention described therein, by applying a batter containing a high proportion of water to a noodle sheet food product, it is possible to obtain a cooked steamed, bean-jam-filled food product that has the same moist, smooth, and soft skin texture and appearance (glossy, white) as conventional steamed, bean-jam-filled foods, even when prepared in a microwave oven.

[0004] However, cooked steamed and stuffed foods made using the above technology use batter that is not normally used in steamed and stuffed foods, so they have a different appearance from regular steamed and stuffed foods and may not be suitable for production on existing factory production lines. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] US202218085830.A Summary of the Invention

[0006] To provide a shumai skin for frozen shumai that can be stably produced, can be easily heated and cooked by heating in a microwave oven without using a food wrap film or wetting with water, and can suppress hardening of the shumai skin during microwave heating, and a frozen shumai using the shumai skin. Another object of the present invention is to provide a frozen shumai that can be stably produced, can be easily heated and cooked by heating in a microwave oven without using a food wrap film or wetting with water, and can suppress hardening of the shumai skin when heated in the microwave oven.

[0007] The inventors discovered that the above object can be achieved by blending water-soluble cellulose ether, phospholipids, and citric acid into the shumai skin of frozen shumai, or by blending water-soluble cellulose ether and phospholipids and adjusting the pH to a specific level or below, and thus completed the present invention.

[0008] That is, the present invention is as follows.

[0009] The present invention provides a shumai skin for frozen shumai, which comprises a water-soluble cellulose ether, a phospholipid, and citric acid.

[0010] The present invention provides a shumai skin for frozen shumai, which contains a water-soluble cellulose ether and a phospholipid and has a pH of 5.9 or less.

[0011] The present invention also provides a method for producing frozen shumai, which comprises a step of enclosing a filling in any of the above-mentioned shumai skins for frozen shumai.

[0012] The present invention provides a frozen shumai having a frozen shumai skin containing a water-soluble cellulose ether, a phospholipid, and citric acid.

[0013] The present invention provides a frozen shumai having a shumai skin containing a water-soluble cellulose ether and a phospholipid, and having a pH of 6.2 or less after thawing. DETAILED DESCRIPTION OF THE INVENTION

[0014] A preferred embodiment for carrying out the present invention (hereinafter simply referred to as "the present embodiment") will be described in detail below. The present embodiment is an example for explaining the present invention, and is not intended to limit the present invention to the following content. The present invention can be carried out with appropriate modifications within the scope of its gist.

[0015] In this specification, "frozen shumai" refers to shumai that has been wrapped in a filling and cooked by heat such as steaming, and then frozen. "Frozen shumai skin for shumai" refers to shumai skin that is used for frozen shumai. "Frozen shumai skin" refers to shumai skin that is frozen. "Frozen shumai skin" is preferably shumai skin that has been cooked by steaming, etc. Hereinafter, when simply referring to shumai skin, it can be understood depending on the context whether it refers to one or both. "Naka-gu" refers to the filling (minced meat, chopped vegetables, seasonings, etc.) that is wrapped around the shumai skin.

[0016] <Shumai skin> It is important that the shumai skin of one embodiment of the present invention contains water-soluble cellulose ether, phospholipid, and citric acid in addition to the usual ingredients such as wheat flour, etc. By including these ingredients, hardening of the shumai skin that occurs when frozen shumai is heated in a microwave oven can be suppressed. Furthermore, the pH of the frozen shumai skin, measured after thawing, is preferably 6.2 or less, and if it is below this upper limit, hardening of the shumai skin during microwave heating can be more effectively prevented. In this specification, the "pH measured after thawing" includes the pH measured after thawing the frozen shumai skin that constitutes the frozen shumai and separating it from the filling. The pH of the shumai skin for frozen shumai is preferably 5.9 or less. If the pH is below this upper limit, hardening of the shumai skin during microwave heating can be more effectively prevented when used to produce frozen shumai. Furthermore, it is more preferable that the water-soluble cellulose ether contains hydroxypropyl methylcellulose (hereinafter also referred to simply as "HPMC") and / or methylcellulose (hereinafter also referred to simply as "MC"), and the use of these ingredients can further suppress the hardening of the shumai skin.

[0017] (Ingredients for shumai skin) The ingredients of the shumai wrapper typically include cereal flour and salts. Examples of cereal flour include wheat flour (soft flour, medium flour, and / or bread flour), rice flour, soy flour, corn flour, etc. Examples of salts include table salt. Other ingredients for the shumai wrapper include vegetable protein, vegetable oils and other fats, starch such as modified starch, and carbohydrates. Vegetable protein and starch can be used as substitutes for part or all of the grain flour. Furthermore, a pH adjuster, such as sodium lactate, can also be added.

[0018] Examples of modified starches include acetate starch, phosphorylated starch, phosphate cross-linked starch, hydroxypropyl starch, hydroxypropylated phosphate cross-linked starch, etc. Examples of carbohydrates include xylose, trehalose, reduced starch syrup, etc.

[0019] (Water-soluble cellulose ether) The shumai skin of the present invention contains a water-soluble cellulose ether. The water-soluble cellulose ether is a cellulose derivative of a water-soluble polymer, such as MC or HPMC. MC and HPMC have properties that are the exact opposite of conventional thickening polysaccharides, which "solidify when heated." They are soluble in both cold and hot water, have stable viscosity with little change over a relatively wide pH range, and have effects such as thickening, water retention, and suspension stabilization.

[0020] (MC / HPMC) The MC used in the shumai skin of the present invention preferably contains methoxy groups, for example, 25.0 to 33.0% by mass of methoxy groups. The HPMC preferably contains methoxy groups and hydroxypropoxy groups, for example, 19.0 to 24.0% by mass of methoxy groups and 4.0 to 12.0% by mass of hydroxypropoxy groups. The viscosity of the MC and HPMC is, for example, in the viscosity range of 2800 to 5600 mm. 2 / s (2% aqueous solution, 20°C). Examples of HPMC used in the shumai skin of the present invention include "Metolose (registered trademark) NE-4000 for food additives" manufactured by Shin-Etsu Chemical Co., Ltd. In the present invention, of MC and HPMC, the use of HPMC in the shumai skin is preferred, as it is particularly effective in improving the hard texture after heating in a microwave oven.

[0021] (Action of water-soluble cellulose ether) The present inventors have found that water-soluble cellulose ethers are effective in preventing the hardening of shumai skin during microwave heating. The present inventors speculate that the hardening of shumai skin occurs due to a phenomenon similar to food vitrification, in which the moisture in the shumai skin evaporates during cooking with microwaves, such as in a microwave oven, and the skin hardens as it dries. Furthermore, it has been empirically confirmed that microwaves are more likely to be concentrated in the parts of the shumai skin that are further away from the filling than in the parts that are in contact with the filling, resulting in a harder finished product.

[0022] Therefore, in order to prevent the shumai skin from hardening, it is possible to increase the moisture content of the shumai skin, but if more water is added during the preparation process to increase the moisture content, the noodle sheets will become soft and sticky, making them less likely to break and less smooth (noodle sheet suitability), and making it difficult to shape them smoothly.

[0023] Therefore, when water-soluble cellulose ether was added to the shumai skin, it was found that the hardening of the shumai skin could be suppressed. It is speculated that this is due to the rubberization phenomenon, which is the opposite of vitrification. Water-soluble cellulose ether has reversible thermal gelation properties, gelling when heated and softening when the temperature drops. It is speculated that the gelation of the shumai skin during microwave cooking makes it difficult for moisture to be released, resulting in the softening at eating temperature.

[0024] The lower limit of the content of water-soluble cellulose ether is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and even more preferably 0.5% by mass or more, based on 100% by mass of the shumai skin. If the content of water-soluble cellulose ether is 0.05% by mass or more, hardening of the shumai skin can be sufficiently suppressed when heated in a microwave oven. There is no particular upper limit to the content of water-soluble cellulose ether, but it is preferably 2.5% by mass or less, more preferably 2.0% by mass or less, and even more preferably 1.5% by mass or less, based on 100% by mass of the shumai skin. If the content of water-soluble cellulose ether is 2.5% by mass or less, the shumai skin will not become too soft when heated in a microwave oven. In particular, it is preferable that the content of HPMC and / or MC is within the above ranges.

[0025] (phospholipids) The shumai skin of the present invention contains phospholipids. Phospholipids are a general term for lipids containing phosphorus, and examples thereof include plant lecithins, such as lecithin derived from rapeseed or soybeans, and egg yolk lecithin obtained by extraction from egg yolk. These phospholipids are known to have emulsifying, dispersing, and wetting properties. Examples of lecithins include lecithin (e.g., soybean lecithin, egg yolk lecithin, sunflower lecithin) and enzymatically hydrolyzed lecithin (e.g., soybean lysolecithin, egg yolk lysolecithin), with lecithin being preferred, and soybean lecithin being particularly preferred. Examples of lecithin include powdered lecithin, liquid lecithin, and fractionated lecithin obtained by fractionating and purifying liquid lecithin. Examples of lysolecithin include powdered lysolecithin, liquid lysolecithin, and fractionated lysolecithin. In the present invention, powdered lecithin is particularly preferred from the viewpoint of ease of use. For example, a product called "SLP-White" manufactured by Tsuji Oil Mills Co., Ltd. can be mentioned.

[0026] The lower limit of the phospholipid content is preferably 0.01% by mass or more, more preferably 0.10% by mass or more, and even more preferably 0.20% by mass or more, based on 100% by mass of the shumai skin. A phospholipid content of 0.01% by mass or more effectively prevents the shumai skin from hardening during microwave heating under conditions of a water-soluble ether, a pH of a specific value or less, or the presence of citric acid, and also provides a good melt-in-the-mouth texture. There is no particular upper limit for the phospholipid content, but a content of 1.00% by mass or less is preferred based on 100% by mass of the frozen shumai skin. A content of 1.00% by mass or less improves noodle sheet suitability (noodle sheet smoothness and / or tear resistance), and 0.75% by mass or less is more preferred.

[0027] In the present invention, phospholipids are presumed to have an anti-deterioration effect on the shumai skin, inhibiting hardening of the skin over time. Phospholipids also improve the smoothness and tear resistance of the noodles, contributing to the stable production of noodle sheets.

[0028] (citric acid) The shumai skin of the present invention may contain citric acid. Citric acid is an organic compound found in citrus fruits and is known as an acidulant and pH adjuster. In the present invention, the concept of citric acid may include not only citric acid but also citrates, such as sodium citrate. For example, the product name "Citric Acid (Anhydrous)" manufactured by Iwata Chemical Industry Co., Ltd. may be mentioned.

[0029] The lower limit of the citric acid content is preferably 0.01% by mass or more, more preferably 0.07% by mass or more, and even more preferably 0.10% by mass or more, based on 100% by mass of the shumai skin. A citric acid content of 0.01% by mass or more effectively prevents the shumai skin from hardening when heated in a microwave oven and ensures a good melt-in-the-mouth texture. There is no particular upper limit for the citric acid content, but it is preferably 0.70% by mass or less, based on 100% by mass of the shumai skin. A content of 0.70% by mass or less improves the noodle sheet suitability, and 0.55% by mass or less is more preferred.

[0030] In the present invention, it is presumed that citric acid lowers the pH of the shumai skin to the acidic side, thereby improving the stretchability of gluten and contributing to maintaining the softness.

[0031] In the present invention, we have found that using a combination of phospholipids, water-soluble cellulose ether, and citric acid improves the melt-in-the-mouth texture of shumai skin. Although the mechanism of action is unknown, we have found that blending a water-soluble cellulose ether with phospholipids and citric acid (hereinafter simply referred to as "combining phospholipids and citric acid") into shumai skin is effective in preventing hardening of the skin during microwave heating. The phospholipids and citric acid may be combined as separate formulations, or a formulation that already combines phospholipids and citric acid may be used. For example, the "Resion (registered trademark)" series manufactured by Riken Vitamin Co., Ltd. may be used. The mass ratio of phospholipids to citric acid in the shumai skin may be, for example, 4.0 to 1.0:1.0 (phospholipid:citric acid, hereinafter the same), preferably 3.0 to 1.1:1.0, and more preferably 2.5 to 1.2:1.0.

[0032] The lower limit of the phospholipid and citric acid content is preferably 0.03% by mass or more, more preferably 0.17% by mass or more, and even more preferably 0.30% by mass or more, based on 100% by mass of the shumai skin. If the phospholipid and citric acid content is 0.03% by mass or more, the shumai skin is well prevented from hardening when heated in a microwave oven and has a good melt-in-the-mouth texture. There is no particular limit to the upper limit of the phospholipid and citric acid content, but it is preferably 1.70% by mass or less, based on 100% by mass of the shumai skin. If it is 1.70% by mass or less, the noodle sheet suitability is good, and 1.00% by mass or less is more preferable. The blending amount of phospholipid and citric acid refers to the total blending amount of phospholipid and citric acid.

[0033] In the present invention, the pH may be adjusted to a suitable upper limit or lower using a pH adjusting component, such as an organic acid other than citric acid or phosphoric acid, as described below. However, the use of citric acid is preferable because it can lower the pH with a small amount of addition, making it easier to soften the gluten in the flour, and it is less likely to volatilize, allowing it to act more uniformly on the flour even during mass production.

[0034] (Oils and fats) The shumai skin of the present invention may further contain oil or fat. It is believed that adding oil or fat makes the skin smoother. The oil or fat is not particularly limited and may be any of animal oils, vegetable oils, fractionated oils thereof, or processed oils or fats thereof (those that have been subjected to one or more of hardening and interesterification). Vegetable oils are preferred, and examples thereof include rapeseed oil, soybean oil, corn oil, safflower oil, rice oil, rice bran oil, cottonseed oil, sunflower oil, high oleic sunflower oil, peanut oil, sesame oil, and olive oil.

[0035] The lower limit of the amount of fat or oil to be blended is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, based on 100% by mass of the shumai skin. The upper limit of the amount of fat or oil is not particularly limited, but is preferably 1.5% by mass or less, more preferably 1.2% by mass or less, based on 100% by mass of the shumai skin.

[0036] (Carbohydrates) The shumai skin of the present invention may further contain carbohydrates. The addition of carbohydrates is expected to inhibit starch retrogradation and improve freezing resistance. The carbohydrates are not particularly limited, and may be any of monosaccharides (glucose, fructose, galactose, mannose, etc.), disaccharides (lactose, sucrose, maltose, trehalose, etc.), oligosaccharides, and sugar alcohol polysaccharides. Disaccharides are preferred, and trehalose is particularly preferred.

[0037] The lower limit of the amount of carbohydrates is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, based on 100% by mass of the shumai skin. The upper limit of the amount of carbohydrates is not particularly limited, but is preferably 2.5% by mass or less, more preferably 1.5% by mass or less, based on 100% by mass of the shumai skin.

[0038] (Other ingredients) When the shumai skin contains cereal flour, the proportion of cereal flour in 100% by mass of the shumai skin is preferably 60% by mass or more, more preferably 64% by mass or more, and even more preferably 68% by mass or more. The proportion of cereal flour in the shumai skin is preferably 80% by mass or less, more preferably 75% by mass or less, and even more preferably 71% by mass or less. In particular, the proportion of wheat flour in 100% by mass of the shumai skin is preferably 62% by mass or more, and more preferably 67% by mass or more. The proportion of wheat flour in 100% by mass of the shumai skin is preferably 78% by mass or less, and more preferably 71% by mass or less. Of the total amount of cereal flour and starch constituting the shumai skin, the proportion of wheat flour is preferably 70% by mass or more, more preferably 80% by mass or more, and particularly preferably 90% by mass or more.

[0039] When the shumai skin contains salt, the salt content is preferably 0.5% by mass or more, more preferably 0.6% by mass or more, and even more preferably 0.7% by mass or more, based on 100% by mass of the shumai skin. The salt content in the shumai skin is preferably 1.5% by mass or less, more preferably 1% by mass or less, and even more preferably 0.9% by mass or less.

[0040] The starch content is preferably 0.5% by mass or more, more preferably 2% by mass or more, based on 100% by mass of the shumai skin. The starch content in the shumai skin is preferably 11% by mass or less, more preferably 3% by mass or less. The starch referred to here means starch extracted from cereal flour, etc., and is to be distinguished from cereal flour.

[0041] Furthermore, the above-mentioned vegetable protein refers to vegetable protein powder. Examples of vegetable protein powders include bean-derived protein powders and wheat-derived protein powders. Examples of beans in bean-derived protein powders include soybeans and peas. For example, bean-derived protein powders include isolated protein powders and concentrated protein powders. Concentrated protein powders are powders obtained by concentrating and drying protein and soybean pulp from defatted beans such as defatted soybeans. Isolated protein powders are powders obtained by separating and drying proteins from defatted beans such as defatted soybeans. For example, isolated protein powders are obtained by adding acid to soy milk obtained by defatting beans and extracting them with water to produce whey and curd. The curd portion is separated by centrifugation or filtering, neutralized, dried, and pulverized. Examples of wheat protein powders include gluten, gliadin, glutenin, etc.

[0042] When the shumai skin contains vegetable protein, the vegetable protein content is preferably 0.5% by mass or more, more preferably 1% by mass or more, based on 100% by mass of the shumai skin. The vegetable protein content in the shumai skin is preferably 12% by mass or less, more preferably 10% by mass or less.

[0043] The content in the shumai skin may be applicable to either the shumai skin for frozen shumai or the frozen shumai skin, but usually it is only applicable to the shumai for frozen shumai.

[0044] The moisture content of the frozen shumai skin is, for example, preferably 15% by mass or more, more preferably 20% by mass or more, and even more preferably 21% by mass or more, based on 100% by mass of the shumai skin. The moisture content of the frozen shumai skin is, for example, preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 24% by mass or less, based on 100% by mass of the shumai skin. The moisture content here can be, for example, the amount of water added during the production of the noodle sheet.

[0045] (pH of shumai skin) The shumai skin for frozen shumai of the present invention preferably has a pH of 5.9 or less, more preferably 5.5 or less, and more preferably 5.0 or less at 25 to 35°C. If the pH is 5.9 or less, when used for frozen shumai, hardening of the shumai skin during heating in a microwave oven without wrapping is well suppressed. There is no particular restriction on the lower limit of the pH, but for example, it is preferably 4.0 or more, more preferably 4.3 or more, and even more preferably 4.7 or more, which will result in good suitability for noodle sheets. In this specification, the pH may be any value within a specified temperature range.

[0046] The shumai skin for frozen shumai of the present invention preferably has a pH of 5.6 or less, more preferably 5.5 or less, and even more preferably 5.0 or less, after steaming at 40 to 80°C. If the pH is 5.6 or less, when used for frozen shumai, the hardening of the shumai skin during heating in a microwave oven without wrapping is more effectively prevented. There is no particular restriction on the lower limit of the pH, but for example, it is preferably 4.0 or more, more preferably 4.3 or more, and even more preferably 4.7 or more, which improves the suitability for noodle sheets. The measurement temperature range is preferably 48 to 63°C.

[0047] The pH of the frozen shumai skin of the present invention, measured after thawing at 11 to 21°C, is preferably 6.2 or less, more preferably 5.9 or less, and more preferably 5.5 or less. A pH of 6.2 or less effectively prevents the shumai skin from hardening when heated in a microwave oven without wrapping. There is no particular restriction on the lower limit of the pH, but it is preferably 4.0 or more, more preferably 4.5 or more, and even more preferably 5.2 or more, which improves the suitability for noodle sheets. The frozen shumai skin is measured after thawing, for example, by the method described in the Examples below.

[0048] Unless otherwise specified, the pH measurement of frozen shumai skin is the pH of the shumai skin at the noodle sheet stage.

[0049] Preferably, the pH of the frozen shumai skin can be measured as follows. The measuring device may be a commercially available pH sensor, for example, the "testo 206-2-pH meter (for food use)" manufactured by Testo Corporation. (1) Prepare the shumai pastry dough or shumai pastry before steaming. (2) Insert the pH meter probe into the shumai skin and once the reading has stabilized, measure the pH value and temperature. The pH of the steamed frozen shumai skin can be measured by using the steamed skin instead of the noodle dough before steaming, and can be measured by the method described in the Examples below.

[0050] The pH of frozen shumai skin can be measured in the same way as above. However, since the skin of only one frozen shumai may not be enough to measure the pH, peel the skin from multiple frozen shumai packaged in the same packaging and mix them together (each piece is approximately 5-30 mm in size). Approximately 30 g of this can be rolled into a ball about 3 cm in diameter, and the pH meter probe can be inserted into the ball to measure the pH.

[0051] The pH of the shumai skin can be adjusted appropriately using ingredients of the shumai skin, such as sodium lactate, citric acid, phosphoric acid, glucono-delta-lactone, lactic acid, acetic acid, and vinegar.

[0052] <Frozen Shumai> The frozen shumai of the present invention is prepared by encasing a filling in the above-mentioned shumai skin and freezing the filling, and it is preferable that the filling contains a certain amount of onion.

[0053] (Main ingredients of filling) The ingredients contained in the filling are not particularly limited and may include meat, seafood, vegetables, mushrooms, etc. Examples of meat include pork, chicken, and beef. Examples of seafood include shrimp, crab, squid, white fish, clams, and scallops. Examples of vegetables include onions, Chinese cabbage, cabbage, bamboo shoots, leeks, and ginger. Examples of mushrooms include shiitake mushrooms, king oyster mushrooms, and enoki mushrooms. The meat content in the filling is preferably 80% by mass or less, and more preferably 70% by mass or less. When seafood is also contained in the filling, the amount of seafood is also included in the amount of meat. Furthermore, the total amount of meat, onions, and other vegetables is preferably 50% by mass or more, and more preferably 60% by mass or more, of the total amount of the filling.

[0054] (Onion content) Among these, onion is suitable for increasing the moisture content of the filling, and it is presumed that increasing the moisture content of the filling prevents the shumai skin from drying out when heated in a microwave oven, further contributing to preventing the shumai skin from hardening. The onion content is preferably 5% by mass or more, and more preferably 10% by mass or more, based on 100% by mass of the filling. From the viewpoints of flavor, texture, and juiciness, the upper limit of the onion content is preferably 40% by mass or less, and more preferably 25% by mass or less, based on 100% by mass of the filling. The onion content is preferably 10% by mass or more, and more preferably 20% by mass or more, based on the amount of meat in the filling. The meat content in the filling is, for example, preferably 30% by mass or more, and more preferably 35% by mass or more.

[0055] (Other ingredients for filling) When preparing the filling, common food additives such as seasonings such as salt, sugar, soy sauce, amino acid salts, nucleic acid salts, yeast extract, and meat extract, starch and modified starch, animal proteins such as egg white, gelatin, and casein, colorings, acidulants, and flavorings may also be added as appropriate.

[0056] <Method of manufacturing shumai skin> The manufacturing process for the shumai skin of the present invention is not particularly limited and can be produced by a conventional manufacturing method, for example, through (1) a mixing step, (2) a rolling step, and (3) a molding step. When the molding step is carried out using a mold, it is sometimes called a "molding step" (the same applies to step (6) below). A suitable manufacturing method will be described below.

[0057] (1)Mixing process This is the process of mixing the ingredients. Water is added to the shumai pastry dough ingredients, and the ingredients are mixed at an appropriate speed using, for example, a horizontal twin-shaft mixer or a vertical mixer until the ingredients are uniform. The dough is then kneaded until it is smooth and elastic, and then allowed to rest for a certain period of time. The order in which the shumai pastry dough ingredients are mixed is not particularly limited, but for example, powder ingredients such as wheat can be mixed in advance, followed by salt and liquid ingredients (e.g., oil and water). Preferably, phospholipids and citric acid are mixed as part of the powder ingredients.

[0058] (2) Rolling process This is the process of rolling the rested dough. For example, using a multi-stage roller, the dough is rolled to a uniform thickness to form a noodle sheet. If the noodle sheet thickness is 0.30 mm or more, there is little concern about drying or tearing of the dough during production, and if it is 0.7 mm or less, it is good for imparting the appearance and texture of shumai. Note that the shumai skin after steaming may be, for example, 0.35 mm or more, or 0.40 mm or more, and 0.80 mm or less, 0.75 mm or less, etc.

[0059] (3) Molding process This is the process of forming the rolled dough (noodle sheet) into the required shape. For example, a die-cutting machine or noodle cutter is used to form the dough into a square, circle, or other shape. Note that the frozen shumai skin of the present invention does not require the use of flour during the forming process.

[0060] <How to make frozen shumai> The frozen shumai of the present invention can be produced by a known production method, for example, through the steps of (4) processing the ingredients, (5) mixing, (6) shaping, (7) steaming, (8) freezing, and (9) packaging. A suitable production method is described below.

[0061] (4) Ingredient processing This is the process of cutting the filling ingredients into the appropriate shape. The main ingredients are cut to the appropriate size and prepared as needed. For example, meat is ground and vegetables are finely chopped. This process makes it easier for the ingredients to mix evenly, resulting in a better balance within the shumai.

[0062] (5) Mixing process This is the process of mixing ingredients that have been cut and processed. For example, using a horizontal twin-shaft mixer, seasonings and additives are added to the ingredients, and the whole is mixed at an appropriate speed until it is uniform. This process brings together the texture and flavor of the ingredients, forming the basis for a delicious shumai.

[0063] (6) Molding process This is the process of shaping the mixed ingredients into shumai. The mixed ingredients are wrapped in the shumai skin of the present invention using a special tool or by hand, and then shaped into shumai. For example, the shaping process of the shumai skin and the shaping process of the shumai can be performed at the same time. In other words, after the skin is rolled to a predetermined thickness, the ingredients can be pressed into a cylindrical shape and wrapped on the skin at the same time that it is cut into individual pieces.

[0064] (7) Steaming process This is the process of steaming the shaped shumai. By steaming the shaped shumai at the right temperature for the right time, the ingredients are thoroughly cooked and delicious shumai is completed. The ideal steaming temperature is 90-100°C and the time is 10-13 minutes.

[0065] (8) Freezing process This is the process of freezing the steamed shumai. In this process, it is important to quickly freeze the shumai in a short period of time to maintain their quality. Rapid freezing maintains the flavor and texture of the shumai, allowing them to be delicious even after thawing. Rapid freezing is preferably done using cold air at -30°C or below, to cool them to below the maximum ice crystal formation temperature (-5°C to -1°C) within 30 minutes.

[0066] (9) Packaging process This is the process of packaging the frozen shumai. Appropriate packaging materials are used to prevent the shumai from drying out or breaking. The packaged shumai are stored under refrigerated conditions to maintain their quality until they are delivered to consumers.

[0067] The frozen shumai of the present invention can be easily cooked when heated in a microwave oven, since it does not require any food wrap film, microwave cover, special container, or special heating packaging, and it is not necessary to moisten or add water to the frozen shumai. Furthermore, when eaten after microwave heating, the skin does not feel hard and melts smoothly in the mouth. Note that the shumai can be eaten by heating in a microwave oven, for example, until the core temperature reaches 50°C to 80°C (about 80% is about 60°C or higher). The wattage of the microwave oven can be, for example, 500W, 600W, 1000W, or 1500W.

[0068] Although the present invention has been described above using embodiments, it goes without saying that the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various modifications and improvements can be made to the above embodiments. Furthermore, it is clear from the claims that such modifications and improvements can also be included within the technical scope of the present invention. [Example]

[0069] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the examples shown below.

[0070] <Manufacturing shumai skin dough> The ingredients for the shumai skin listed in Table 1 (total amount of approximately 2000 g) were prepared, and the shumai skins of Examples 1 to 9 and Comparative Examples 1 to 6 were produced through (1) a mixing process, (2) a rolling process, and (3) a molding process. (1)Mixing process Using a vertical mixer (model number B464711) manufactured by Hitachi, Ltd., the powder ingredients (ingredients shown in the table selected from wheat flour, modified starch, soybean flour, vegetable protein, trehalose (sugar), hydroxypropylmethylcellulose, methylcellulose, lecithin (phospholipid), citric acid, and acetic acid) were mixed at medium speed for 1 minute, and then an aqueous solution of salt, sodium lactate, and, in some cases, vegetable oil was added and mixed for 7 minutes. (2) Rolling process The obtained dough was rolled up in a noodle roll and rolled out in a molding machine (two-stage rolling) without combining or dusting with flour to obtain noodle sheets with a thickness of 0.4 to 0.45 mm. (3) Molding process The noodle dough was cut into 80mm x 75mm squares and shaped to prepare shumai skins.

[0071] <Production of frozen shumai> Using the ingredients listed in Table 2, frozen shumai were produced using the shumai skins of Examples 1 to 9 and Comparative Examples 1 to 6 through the steps of (4) processing the ingredients, (5) mixing, (6) molding, (7) steaming, and (8) freezing. Note that the (9) packaging step was omitted. (6) In the molding process, 25g (per piece) of the mixed filling was wrapped in one shumai skin, (7) in the steaming process, it was steamed for 11 minutes in a steamer, and (8) in the freezing process, it was flash-frozen in cold air below -30°C to below the maximum ice crystal formation zone (-5°C to -1°C) for 30 minutes or less.

[0072] (Evaluation 1a) pH of shumai skin before steaming The pH before the steaming process and the skin temperature at the time of measurement were measured for the shumai skins obtained in Examples 1 to 9 and Comparative Examples 1 to 6. The measuring device used was a "Testo 206-2 pH meter (for food use)" (Model number: 0563.206 2) manufactured by Testo Corporation, and measurements were performed using the following method. The dough before rolling obtained in the (1) mixing step of producing the shumai skin dough was pressed into a ball-like shape to prepare a measurement sample, which was then inserted with the pH meter probe. Once the readings stabilized, the pH value and temperature were measured.

[0073] (Evaluation 1b) pH of shumai skin after steaming As in (Evaluation 1a), the dough was solidified into a ball-like shape to create a measurement sample, which was then steamed in accordance with the (7) steaming step in the production of frozen shumai, and the pH value and temperature were measured in the same manner as in (Evaluation 1a).

[0074] (Evaluation 1c) pH of thawed shumai skin Nine frozen shumai were placed in a circular dish measuring 22 cm in diameter and 30 mm deep in plan view, covered with 30 cm x 30 cm plastic wrap, and left to thaw in a refrigerator at 2 to 6°C for 3 hours. The insides of the thawed shumai were discarded and the skins were collected. The skins from the nine shumai were then solidified into balls using the procedure described above to create measurement samples, which were then inserted with the probe of a pH meter. Once the readings stabilized, the pH and temperature were measured.

[0075] The results are shown in Table 1. In Examples 1 to 9, the pH before the steaming step was 5.9 or less, whereas in Comparative Examples 1, 2, 4 and 5, the pH was 6.0. Furthermore, in Examples 1 to 9, the pH after thawing was 6.2 or less, whereas in Comparative Examples 1, 2, 4 and 5, the pH was 6.3.

[0076] (Evaluation 2) Dough suitability for the shumai skin (smoothness and tearability) The shumai skin doughs of Examples 1 to 9 and Comparative Examples 1 to 6 were evaluated by four trained panelists according to the following criteria from the viewpoint of (2) the suitability of the noodle sheet when it emerged from the rolling machine in the rolling process, based on whether the surface of the noodle sheet was smooth and not crumbly, and whether the noodle sheet was difficult to tear.

[0077] (Scoring criteria) 5 points: Very good 4 points: good 3 points: Average 2 points: poor 1 point: Very poor (Evaluation points) The highest and lowest scores were excluded from the scoring results of the four people, and the average score of the two people was calculated and rounded up. For example, if four people give scores of 5, 4, 3, and 3, the 5 and 3 points will be excluded, and the average of the 4 and 3 points, 3.5, will be rounded up to the nearest decimal point to arrive at 4 points.

[0078] (Rating 3) Texture <Hardness> (Rating 4) Texture <melts in the mouth> The frozen dumplings using the shumai skins of Examples 1 to 9 and Comparative Examples 1 to 6 were evaluated by a panel of experts in terms of texture (hardness) and texture (melt-in-the-mouth). The frozen shumai were removed from the freezer, and five pieces of each example and comparative example were placed on a plate. Without any covering such as food wrap or adding water to the frozen shumai, they were heated at 600W in a Sharp Corporation microwave oven "RE-SF10-W" until the core temperature reached 50-80°C (about 80% was about 60°C). Four trained panelists rated the cooked shumai according to the following criteria. The judging was done both immediately after cooking and after leaving the shumai for a few minutes.

[0079] (Grading criteria for texture <hardness>) 5 points: You can't feel the hardness of the skin when you put it in your mouth. 4 points: You can barely feel the hardness of the skin when you put it in your mouth. 3 points: The skin feels a little hard when you put it in your mouth, but it's tolerable 2 points: The skin feels hard when you put it in your mouth, making it quite difficult to eat. 1 point: The skin feels hard when you put it in your mouth, making it very difficult to eat. (Evaluation points) The highest and lowest scores were excluded from the scoring results of the four people, and the average score of the two people was calculated, rounded up. For example, if four people give scores of 5, 4, 3, and 3, the 5 and 3 points will be excluded, and the average of the 4 and 3 points, 3.5, will be rounded up to the nearest decimal point to arrive at 4 points.

[0080] (Scoring criteria for texture <melt in the mouth>) 5 points: Very good melt-in-the-mouth texture 4 points: Melts in the mouth very well 3 points: Melts easily in the mouth 2 points: Slightly poor melt-in-the-mouth feel 1 point: Poor melt-in-the-mouth texture (Evaluation points) The highest and lowest scores were excluded from the scoring results of the four people, and the average score of the two people was calculated and rounded up. For example, if four people give scores of 5, 4, 3, and 3, the 5 and 3 points will be excluded, and the average of the 4 and 3 points, 3.5, will be rounded up to the nearest decimal point to arrive at 4 points.

[0081] [Table 1]

[0082] [Table 2]

[0083] As is clear from the results shown in Table 1, the frozen shumai of Examples 1 to 9 had good noodle sheet suitability and were good in both texture (hardness) and texture (melt in the mouth). In contrast, Comparative Examples 1 and 4 were poor in both texture (hardness) and texture (melt in the mouth). Comparative Examples 2 and 5 were poor in noodle sheet suitability, texture (hardness), and texture (melt in the mouth). Comparative Example 3 was also poor in noodle sheet suitability and texture (melt in the mouth). Comparative Example 6 was poor in noodle sheet suitability. Comparative Examples 1 to 5 were completely unsuitable for eating after cooking without wrapping, and Comparative Example 6 could not be produced stably.

[0084] (Comparative Example 7) In Comparative Example 7, shumai skin containing HPMC but not containing phospholipids or citric acid was prepared in the same manner as in Example 1, except that the formulation shown in Table 3 below was used. Frozen shumai were prepared using the shumai skin, and then thawed, heated in a microwave oven, and eaten in the same manner as in Example 1. As a result, Comparative Example 7 was better than Comparative Example 1 in that the drying of the skin was suppressed, but the presence of the skin due to gluten formation was noticeable, and the skin was hard, especially in the part not attached to the filling, and both the texture (hardness) and texture (melt-in-the-mouth) were inferior, making it unsuitable for eating after cooking without wrapping.

[0085] (Comparative Example 8) In Comparative Example 8, a shumai skin containing HPMC and phospholipids but no citric acid was prepared in the same manner as in Example 1, except that the formulation shown in Table 3 below was used. Frozen shumai were prepared using the shumai skin, and then thawed, heated in a microwave oven, and eaten in the same manner as in Example 1. As a result, although the presence of the skin due to gluten formation was slightly reduced in Comparative Example 8 compared to Comparative Example 7, both the texture (hardness) and the texture (melt-in-the-mouth) were still inferior, and the shumai skin was not suitable for eating after cooking without wrapping.

[0086] [Table 3]

[0087] The frozen shumai of the present invention has the characteristics of being made using carefully selected ingredients and using traditional methods to have a texture and flavor similar to that of handmade shumai, being able to be stored frozen for a long period of time, being able to be easily cooked without the need for cling film for food use, and being able to more efficiently prevent the skin from hardening when heated in a microwave oven, and being excellent in terms of convenience, nutritional balance, and cost performance, making it an ideal dish for the home dinner table.

[0088] Although each embodiment has been described in detail above, it is not limited to a specific embodiment, and various modifications and changes are possible within the scope of the claims. It is also possible to combine all or a plurality of components of the above-described embodiments. [Industrial Applicability]

[0089] According to the present invention, it is possible to provide shumai skin for frozen shumai that can be stably produced, can be easily heated in a microwave oven without using food wrap film, and can suppress hardening of the shumai skin when heated in a microwave oven, and frozen shumai using this shumai skin. To provide a frozen shumai which can stably produce a shumai skin, can be easily heated and cooked by heating in a microwave oven without using a food wrap film and without wetting with water, and can suppress hardening of the shumai skin during microwave heating.

Claims

1. A shumai wrapper for frozen shumai, characterized by containing 0.05% to 2.5% by mass of one or more selected from hydroxypropyl methylcellulose and methylcellulose, 0.01% to 1.00% by mass of phospholipid, and 0.01% to 0.70% by mass of citric acid.

2. The frozen shumai wrapper according to claim 1, characterized in that the pH is 4.0 or higher and 5.9 or lower.

3. A shumai wrapper for frozen shumai, characterized by containing 0.05% to 2.5% by mass of one or more selected from hydroxypropyl methylcellulose and methylcellulose, and 0.01% to 1.00% by mass of phospholipid, and having a pH of 4.0 to 5.

9.

4. A method for manufacturing frozen shumai, characterized by comprising the step of wrapping a filling in a shumai wrapper for frozen shumai as described in any one of claims 1 to 3.

5. A frozen shumai comprising a filling and a frozen shumai wrapper for enclosing the filling, wherein the frozen shumai wrapper contains 0.05% to 2.5% by mass of one or more selected from hydroxypropyl methylcellulose and methylcellulose, 0.01% to 1.00% by mass of phospholipids, and 0.01% to 0.70% by mass of citric acid.

6. A frozen shumai comprising a filling and a frozen shumai wrapper for enclosing the filling, wherein the frozen shumai wrapper contains 0.05% to 2.5% by mass of one or more selected from hydroxypropyl methylcellulose and methylcellulose, and 0.01% to 1.00% by mass of phospholipids, and the pH after thawing is 4.0 to 6.

2.

7. The frozen shumai according to claim 5 or 6, characterized in that the filling contains 5% by mass or more of onions in 100% by mass of the filling.