JPS6212981B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing fried tofu. Fried tofu in general is originally made from tofu, but the invention of a method for preparing it from an aqueous protein mixture (Japanese Patent Publication No. 46895/1983) was an attempt to eliminate the conventional tofu manufacturing process, which required time and effort. We succeeded in imparting freezing resistance, making it possible to manufacture it using a mass production method. Since then, several inventions have been made in methods for preparing fried tofu from aqueous protein kneading, such as optimizing manufacturing methods for individual types of fried tofu and solving practical problems encountered in mass production. It has been proposed. This invention relates to a method for producing fried tofu from an aqueous protein kneaded product. The original tofu (deep-fried tofu) is made by cutting the normally made tofu into thick pieces, pressing it to dehydrate it to some extent (however, there is more water in the dough than in thin-fried or ganmodoki). Produced by heating in relatively hot oil. One of the reasons for using dehydrated dough in this method is to avoid the phenomenon of the dough sticking to each other or the dough and the heating pan during heating in oil when dehydrated dough is used, and the resulting phenomenon of loss of the product surface structure. The purpose is to prevent
However, when preparing atsuage from an aqueous protein kneading product, simply preparing a dough with the same moisture content as the pressed dehydrated tofu dough will result in the phenomenon of sticking and loss of the product surface structure when heated in oil. , there are drawbacks that make it difficult to prevent. This pecking phenomenon can be prevented by using long chopsticks etc. to avoid contact with each other when heating a small number of pieces in oil, so even if there is no problem,
In mass production, this becomes a bottleneck that requires labor, and to avoid this, the moisture content in the dough must be significantly lowered than in the case of tofu dough for deep-frying, and even more so in the case of tofu dough for ganmodoki (by reducing the content of other solids). This is a problem both in terms of physical properties compared to the original tofu-age and in terms of raw material cost. In an effort to solve the above-mentioned problems in the mass production of fried tofu in a method for producing fried tofu from an aqueous protein mixture, the present inventor discovered that It has been found that it is effective to perform a heat treatment, and that the heat treatment also has the effect of changing the texture of the internal tissue into an extremely favorable one. This invention provides T+
This is a method for producing tofu-age that aims to form a surface structure without swelling the inside after heat treatment such that the value of 35.8log10Hr is in the range of 110±12. , which has a surface structure similar to that of the original tofu-based fried tofu and a tofu-like internal structure that is hardly puffed. The aqueous protein mixture contains vegetable protein and water as essential components, preferably oil and fat, and may further contain starchy substances, sugars, salt, seasonings, PH regulators, high viscosity polysaccharides, vegetables, etc. . The vegetable protein used is one that forms a gel when heated, and examples include soybean protein, peanut protein, cottonseed protein, wheat protein, etc., but soybean protein is preferred from the viewpoint of marketability and price. It is. The higher the protein purity of these proteins, the stronger the gel-forming property and the less unique odor and taste, so it is preferable. The combination of vegetable protein and water is determined by the maximum amount of protein that is sufficient to hydrate the protein with respect to a certain amount of water, and the amount of protein that can be molded by kneading (or kneading and heating in some cases). A relative range is determined with the minimum amount as both ends, and within this range, a zone with more water is preferable because a product with a better internal structure for deep-fried tofu can be obtained. That is,
Protein (as pure content) 45 to 100 parts by weight of water
A range of 15 parts by weight can generally be adopted, but preferably 25 to 15 parts by weight of protein (for example, about 30 to 18 parts by weight of commercially available isolated soybean protein powder) and 40 to 15 parts by weight of fat and oil per 100 parts by weight of water. It is preferable to prepare a kneaded product having a range of parts by weight. The preparation of the aqueous protein kneaded product used in this invention does not require the use of a coagulant commonly used in tofu production, and even if a coagulant is used, it must not be in a curd-like (coagulated state). If a material made into a card by using a coagulant is used as a raw material for a kneaded product, it is not only difficult to obtain a kneaded dough with shape retention unless it is dehydrated, but also the internal structure of the product may not be as thick as the original. A product similar to deep-frying cannot be obtained;
Moreover, the product has extremely poor freezing resistance. This invention does not use a coagulant or does not form a card even if it is used, so it does not have the above drawbacks and is suitable for mass production. When using a coagulant, use a poorly water-soluble coagulant such as calcium sulfate, or use a water-soluble coagulant such as calcium chloride or magnesium sulfate in combination with an alkaline agent to raise the pH of the dough to 6.6 or more.
It is best to use the coagulant within the range of 7.4, so that the dough does not become card-like, and the coagulant used in this way has the effect of making the surface texture of the product favorable. Since finely chopped vegetables and the like can be mixed into the dough, it is possible to obtain a product that is different from the original atsuage in this respect. The dough and aqueous protein kneaded material obtained as described above are molded or subjected to a specific heat treatment while molding.
That is, the heat treatment is performed so that the value of T+35.8log10Hr (hereinafter sometimes referred to as "F value") is in the range of 110±12. Here, T is heating temperature °C, Hr is heating time
Indicates hour. The above value is most preferably around 110. If this value is too low and does not reach 98, it will prevent the phenomenon of sticking when heated in oil, especially the phenomenon of sticking of dough prepared at the above-mentioned preferred protein-water blending ratio. This tends to result in defects in the surface structure during mass production. If the above value is too high and exceeds 122, the internal structure of the product will be hard.
It becomes stale and develops a crumbly texture. A suitable temperature range for the heating temperature is 60°C or higher, preferably 75 to 115°C. Generally, the lower the temperature, the longer the treatment time is required, but at a temperature lower than 60° C., even if the treatment time exceeds the above-mentioned specific value 122, a satisfactory degree of heating will not be achieved. The heat treatment in the present invention has the effect of imparting resistance to swelling of the dough during heating in oil, and contributes to obtaining a good internal structure. The heat treatment in this invention is also preferably carried out under conditions that prevent moisture from escaping. In other words, it is advisable not to perform any "pressing" operations on ordinary tofu during this heat treatment, but also to ensure that moisture does not evaporate from the surface of the kneaded product. The movement of moisture during heat treatment probably prevents the formation of the molecular network structure that should originally form during heating, and also makes the distribution of moisture near the surface and inside uneven, resulting in a good result. The organization's products are not available. Preventing the evaporation of water from the surface of the kneaded material can be achieved by increasing the vapor partial pressure of the atmosphere or by shielding it from an atmosphere with a low water vapor partial pressure. It is preferable to heat it by sealing it in a container or heating it in a humid atmosphere.
The heat treatment is generally performed by heat transfer heating, but other methods that use heat transfer heating and high frequency irradiation heating in combination may also be used. Since the heat-treated kneaded material is then heated in oil, it is not very desirable for water droplets to adhere to the surface of the kneaded material, but there is no problem with the adhesion of oil droplets, so heating by immersion in oil is not a problem. This treatment is a preferred method for mass production. However, as the heating temperature increases, the vapor pressure inside the kneaded material increases, so care should be taken to heat under pressure when a heating temperature of about 100° C. or higher is used. As mentioned above, the heat treatment is performed on the molded product or while it is being molded, and the thickness of the molded product is preferably 10 mm or more and 40 mm or less. 40mm
If it is thicker than that, it will be difficult to heat the inside evenly,
If it is thinner than 10 mm, it will be difficult to suppress swelling of the internal tissue in later steps. Optimal thickness is 15-30mm. In the early stage of the heat treatment, the kneaded material may be in an agitated state by heating, for example, by blowing steam, but it is necessary to keep the kneaded material in a non-stirring state at least in the latter half. The heat-treated kneaded material is then allowed to form a surface structure without causing internal swelling. This treatment is carried out by immersion in heated oil. In the tofu manufacturing method, the temperature of the oil immersed in the oil is usually 180℃.
Although the above temperature is adopted and is a one-stage process, this temperature range has the problem of promoting smoke generation of fats and oils, accelerating deterioration of frying oil, and worsening the working environment. In this invention, a temperature of 180° C. or higher can be employed, but treatment at a lower temperature is also possible, which is advantageous in maintaining a good working environment. The preferred temperature range is
1 to 3 minutes at 125 to 170°C, more preferably
It is recommended to include heating at 145°C or higher for 1 minute or more. The fried tofu food thus obtained has a good structure and texture, and is highly palatable.Furthermore, it does not fall apart when cooked and has excellent freezing resistance, making it suitable for mass cooking, and can be produced even in the summer. There are no particular restrictions on sales or storage. This invention will be explained below with reference to Examples. Example 1 Commercially available isolated soybean protein powder 500 parts, soybean oil 450 parts, water
2,000 parts of horse lees, 75 parts of seasoning, and 25 parts of seasoning were kneaded into a homogeneous dough using a silent cutter, and 150 parts of shredded carrots
Mix 10 parts of sesame seeds and 10 parts of sesame seeds, put this in a tray, adjust the thickness to 25 mm, and steam in a steamer at 85℃ for 10 minutes, 30 minutes.
Heat treatment (F
The values were 92.9, 110.0, and 125.3, respectively), and after cooling for 30 minutes, they were formed into cuts (43 mm x 43 mm x 25 mm). This heat-treated cubic dough is prepared by heating 20 pieces at a time in oil in a pot with an opening of 25 cm x 25 cm (first in oil at 130°C for 1.5 minutes, then in oil at 150°C for 1 minute). minutes), during which no special stirring work was performed as much as possible. The results of comparing the differences in frying conditions and product quality due to differences in heating conditions are as shown in the following table.

[Table] In addition, tofu produced by a conventional method was pressed to make it 80% moisture, cut into pieces the same size as the above dough, and heated in oil at 180℃ for 1 minute to obtain thick fried tofu. The product was boiled in a seasoning liquid to season it together with the product of this example which had been heat-treated at 80°C for 30 minutes, and subjected to a palatability test (comparison of two points). Seventeen of the 20 panelists preferred the product of this example, and the profile of the product of this example that they pointed out was as follows.・Soft feeling ・Smooth feel (inside) ・Like a mountain potato rubbed into it ・Good flavor absorption ・No lumpy texture Example 2 Dough with the same composition as Example 1 was made into a 25 mm square. Fill the casing in a columnar retainer and heat it in an autoclave at 110℃ for 2 minutes, 6 minutes, or
After heating for 13 minutes (F values are 92.9, 110.0, and 122.1, respectively), it was cooled with water, and the casing was peeled off and cut into 25 mm cubes, which were then heated in oil in the same manner as in Example 1. I got the following results.

[Table] Example 3 Add 280 parts of water to 100 parts of isolated soybean protein powder and 100 parts of soybean oil.
350 parts, 400 parts, or 450 parts, knead in a silent cutter, pack into a casing with a fold width of 55 cm, and immerse in hot water at 90°C for 20 minutes (F value is
108.7), then remove it from the casing and
Regarding the cut into a 20mm cube shape,
When heated for 1.5 minutes in oil at 150°C, the conditions during frying were good. Although the appearance (surface structure) of the products was good, the texture of the fried tofu was the best with 400 parts of water, slightly harder with 350 parts of water, and even worse with 280 parts of water. It was hard, and the one containing 450 parts of water was slightly soft. Example 4 500 parts of isolated soybean protein powder, 500 parts of soybean oil, 2100 parts of water
1 part, 5 parts of seasoning, and 10 parts of calcium sulfate dihydrate were kneaded in a Stephan mixer, then finely chopped burdock root,
Add carrots and shiitake mushrooms and place in a tray to a thickness of 30cm.
Packed in mm, heated in a steamer at 85℃ for 30 minutes (F value is
110.0), cut into pieces of 25 x 25 x 30〓, heated in oil at 130°C for 1.5 minutes and 155°C for 1 minute, cooled, and then frozen at -20°C. After freezing for 7 days, they were thawed and evaluated for quality. There was almost no freeze denaturation and the texture was good.

Claims (1)

[Claims] 1 The aqueous kneaded product of protein is heated under conditions that prevent moisture from escaping from the kneaded product, and the value of T + 35.8 log 10 Hr (where T is the heating temperature °C and Hr is the heating time hour) is 110 ± 12
A method for producing tofu-age (deep-fried tofu), which is characterized by forming a surface structure without swelling the inside after heat treatment within the range of .