JPS602157A - Bean curd snack and its preparation - Google Patents

Abstract

PURPOSE:To prepare a bean curd snack which is takable without cooking and has high preservability, by freezing a soya milk gel quickly, drying the frozen gel in vacuum, and adding a seasoning or a coating material to the obtained processed and dried soybean. CONSTITUTION:Raw soybeans are immersed in water, crushed, boiled, and filtered. The obtained soya milk is coagulated by adding a coagulant such as CaCl2 and stirring the mixture. The coagulated product is formed to a soya milk gel having a desired form. The soya milk gel (bean curd gel) is immersed in an aqueous solution of carrageenan of about 1wt% concentration for 15-30min. Proper seasonings or seasoning materials are used in combination with carrageenan in the above process according to the form of the final food to be produced. The pretreated bean curd gel is frozen instantaneously with liquid nitrogen, etc., and is freeze-dried in vacuum by conventional method to a water-content of 5-10%. The dried bean curd is coated with e.g. the confectionary chocolate to obtain the objective bean curd snack.

Description

Detailed Description of the Invention (Objective of the Invention) The present invention uses a processed dried soybean product having a novel morphological structure obtained by quickly freezing soybean milk gel and vacuum drying it as a base material, and adding seasonings or coating materials to the dried soybean product. The present invention relates to a tofu snack that has been added with the following ingredients to provide direct edibility and preservability, and a method for producing the same.

(Prior Art) As is well known, so-called tofu is a food whose composition is about 90% water and also contains a considerable amount of attached water, so it cannot be eaten in any form other than as a cooking food. Not suitable.

On the other hand, with frozen tofu, the water content is reduced by freezing and drying.
Although this is a dry food that has been reduced to around 0%, it is usually rehydrated in hot water to adsorb a large amount of moisture again, swell it, and season it appropriately before it can be eaten. It can also be regarded as a variation of high-moisture food, in that it is a necessary condition for use (edible) to contain a large amount of water when ingested.

Furthermore, when we consider the texture of tofu as a food, excluding the amount of water it contains, so-called tofu has excellent smoothness, but on the other hand, it is only solid and strong, making it difficult to pick with human fingers. On the other hand, air-dried frozen tofu has sufficient strength (firmness) to be used as a solid food, but when placed on the human tongue, it has a rough texture and is tasteless, making it a processed soybean food. The thing is, food science,
This is widely recognized in the fields of nutrition and medicine, and the understanding of general consumers is also deepening.

Despite this, the consumption of these processed soybean products is
It hasn't expanded that much. The main reason for this is that they each have two major drawbacks: high moisture content during feeding, and an imbalance between texture and solid food strength (firmness).

The purpose of this invention is to eliminate two characteristic drawbacks associated with frozen tofu and tofu, namely high moisture during feeding and unbalance in texture and strength, and to create a kind of dried tofu that is directly edible. This objective was achieved by the manufacturing method described below.

That is, the present invention modifies the structure and composition of tofu and frozen tofu, which have heretofore been known only as culinary foods, to produce them as snacks or confectionery, which have hitherto been completely unknown. The first step is
# This is a process for producing a soybean milk gel solid of any given shape, which has a dense and clear texture and has the strength (firmness) to withstand one operation in the second step.

First, raw soybeans are soaked in water, crushed, steamed, and filtered to produce soybean milk. Calcium chloride, magnesium chloride, or calcium sulfate is added to this soymilk, stirred to cause a coagulation and flocculation reaction, and then removed from hot water, placed in a mold box, compressed and dehydrated, cooled by immersion in water, cut into intermediate sizes, and shaped into any desired shape. The soybean milk gel solid (hereinafter referred to as soybean milk gel) is split.

In the above-described first step, the process operations up to intermediate size cutting may be carried out under the usual method conditions for producing momen tofu or fresh tofu for frozen tofu. However, for the purpose of improving the structure of the freeze-dried product and preventing cracks in the second step, it is desirable to incorporate a small amount of carrageenan (sulfated polysaccharide of red algae and seaweed) in the soymilk coagulation and aggregation reaction. The appropriate concentration is 0.02 to 0.1% in the medium.Also, in order to make the final molding operation easy and smooth, the size should be too large for pressing and dehydration.This size and shape is similar to commercially available Karinto,
This is an example of a size and shape comparable to that of sweets such as large candies, chotspas, biscuits, and kutsky sticks. Theoretically, the product of the present invention can be made into a larger shape, but in order to proceed smoothly with the second step, the practical condition is that the maximum thickness is 2 cyn or less. becomes.

The second step is the step of freezing and drying the tofu gel.

First, tofu gel was mixed with about 1% by weight of carrageenan. A 10 to 2% aqueous solution of 10% to 20% is suitable.

In addition, when coffee is used as one of the seasoning substances, the solid content concentration in the aqueous solution is suitably 1 to 2% by weight.

In addition, in place of or in combination with carrageenan in the first step and this step, other suitable water-soluble gums can be used as the Japanese textile improving material.

The pretreated tofu gel is flash frozen using a liquid nitrogen freezing device. In this case, a minimum temperature of -40°C is sufficient, and lower temperatures are not particularly required. Also,
Instead of liquid nitrogen freezing, a quick freezing method using a still air freezing method (including air cutoff freezing in an air blast method) using a mechanical freezing device using Freon or ammonia refrigerant may be used. In short, the freezing conditions at this time only need to be freezing speed and freezing temperature conditions as a means of forming ice crystals as fine as possible. By the way, rapid freezing, which allows food to be frozen quickly, means that it quickly passes through the maximum ice crystal formation zone (-1 to -5°C), and the temperature of the food can easily drop to -18°C (
It is generally accepted that freezing occurs in order to reach an equilibrium temperature (equilibrium temperature). Specifically, 1. Next, the frozen tofu gel that has been rapidly frozen is immediately vacuum freeze-dried in a vacuum freeze-drying apparatus using a conventional method. Generally, in commercial vacuum freeze-drying equipment, the final moisture control system for dried products is currently undeveloped. Therefore, the drying finish status is judged by the product temperature and time curve, but the dried product according to the present invention is
It is desirable to finish the product as a dry product with a moisture content of 0%. Bone-dried food deprives saliva during the day, directly impairing its edibility. Dried tofu gel (hereinafter referred to as
When the moisture content of dried tofu (simply referred to as dried tofu) reaches an absolute dry state (less than 2-3%), store the dried tofu in a sealed container with an appropriate amount of water in the bottom of the container, and naturally humidify it to remove moisture. adjust.

The third step of the present invention is a step of coating dried tofu and a processing method. The purpose of this is to improve the appearance of the product as a snack food or confectionery, while increasing its edibility and shelf life.

- After coating with dried tofu gel, the chocolate is placed on an aluminum vat or a suitable drying rack, and the chocolate is solidified at room temperature of 0 to 20°C and peeled off.

If the seasoning as a food is sufficiently prepared by the pretreatment in the second step, the third step can be omitted.

Through the above first, second and third steps IB, tofu snacks are completed. As is already clear, the composition of this product is a food whose main ingredients are chemical components corresponding to the solid content of tofu or frozen tofu.

Fruit - Example 1).

No water immersion for 16 hours at a water temperature of 15 to 18℃
．． Calcium chloride and carrageenan were prepared in a hot aqueous solution state to a concentration of 2% and 0.02%, and stirred to cause a coagulation and aggregation reaction. After removing the excess separated liquid, the reacted solid content was poured into a mold box, and the load was gradually increased to press and dehydrate the mold to form tofu. The moisture content of tofu (8 x 12 x 4 ax square) obtained by separating, cutting and soaking in cold water was 85%.

Next, cut the tofu into 1X1X43 square pieces, and cut the tofu into a sufficient amount of 10
% coupling sugar aqueous solution for 30 minutes at room temperature. This pretreated shredded tofu was placed in a liquid nitrogen freezing device and flash frozen. Temperature of nitrogen atmosphere is temporarily -80°
The lower limit is -40°C.
The temperature was maintained at -40"0 for 1 hour to ensure complete freezing.Subsequently, the shelf temperature was preliminarily set to -30 to -40".
The sample was cooled to 0 and transferred to a vacuum freeze-drying apparatus, and vacuum freeze-drying was immediately started. Approximately 1 hour after the start of operation, sufficient vacuum was achieved. The maximum degree of vacuum during this time was 8 x 10-"mb.
a r (8Pn), and the maximum product temperature was 20 to 30°C.

The dried product obtained here was almost completely dry, so it was transferred to another airtight container, and warm water was placed in the bottom of the container, and it was naturally humidified for about 5 hours. Pale yellow-white dry tofu pieces were obtained.

Finally, home-made chocolate with a melting point of about 32°C was melted on a hot water bath, and the dried tofu pieces were dipped into it to coat the entire surface, pulled out, and placed side by side on a smooth aluminum vat. Store this in a home freezer for about 20 minutes, and take it out when the temperature has dropped to 10 to 20 degrees Celsius and the chocolate has sufficiently solidified. , the object of the present invention was obtained.

The remaining portion was placed in a walk-in freezer at -20°C and stored frozen overnight (16 hours).

These frozen tofu pieces were vacuum freeze-dried under the same conditions as in Example 1. However, in this case, judging from the product temperature/time curve, the drying process will be terminated at a rather modest stage, the pressure inside the vacuum freeze-drying device will be returned to atmospheric pressure, and the airtight condition will be kept at a low temperature for about 6 hours. Afterwards, the dried material was carried out. The dried product was pale yellowish white and had a moisture content of 8 to 10%.

Finally, chocolate for confectionery industry with a melting point of about 36° C. was melted on a hot water bath, and then a chocolate coating was applied through the same steps as in Example 1 to obtain the final target product.

(Example 3) Fresh tofu processed for frozen tofu production was cut into pieces and immersed in an aqueous solution for 30 minutes at room temperature.

Arrange this on an aluminum tray, wrap the whole thing with Saran wrap, and store it in an air blast type quick-freezing chamber (room temperature -22°C) to avoid direct exposure to outside air.
Freeze overnight (16 hours). Then, vacuum freeze-drying was carried out under the same conditions as in Examples 1 and 2 to obtain a brown stick-like dried product.

(Effect) The product of the present invention obtained as described above was applied to a total of 2 people, 10 confectioners, 5 frozen tofu manufacturers, and 10 murderers.
Table 1 shows the responses collected from the samples given to five people (five people each in Example 3).

Table 1 That is, the characteristics of the product of the present invention as a food are listed as follows. ■This product is suitable for men and women of all ages in terms of aroma, depth, taste, and texture.

■This product has no soy odor at all. Usually, various soybean products have a slight soy odor, but quartz does not have this odor, which is a completely unexpected and favorable effect. ■Refrigerate this product at 5 to 10℃ and store it in a warehouse, and no change in quality will be observed for at least 3 months. In other words, it is considered to be a food that has a longer shelf life and shelf life than ordinary frozen tofu.

■Since the ingredients equivalent to tofu or frozen tofu are preserved, it has extremely high nutritional value. ■It has the appropriate strength (firmness) for confectionery or snack food. That is, there is sufficient direct edibility. ■This product has a simple structure and is easy to manufacture. Therefore, both mass production and small quantity production are possible. ■So-called frozen tofu requires about 20 days for the freeze-denaturation process. Further, the steps after the freezing step are complicated and require a considerable amount of energy. On the contrary,
Quartz does not require a vacuum freeze-drying process that consumes a lot of energy, and it is thought that the product can be supplied at a low price.

It contributes to seasoning as a food. ■The use of carrageenan is
It not only contributes to improving the texture of finished products, but also
Effectively works to prevent cracks in vacuum freeze-dried products. This is thought to be due to a chemical reaction between soybean protein and carrageenan, a sulfated polysaccharide.

■Because liquid nitrogen freezing is so-called instant freezing,
In addition to making ice crystals extremely fine and making the structure of frozen tofu dense and uniform, it also acts as an inert gas to prevent the oxidation of processed foods. This can be understood from the fact that the cross-section of the dried tofu is denser and cleaner than normal frozen tofu and exhibits a light yellowish-white color. Although rapid freezing by mechanical freezing cannot form ice crystals as fine as that by liquid nitrogen, it has the advantage of producing a dense and smooth edible tissue.

Conventionally, in the production of frozen tofu, rapid freezing at -20° C. has not been considered possible due to the necessity of mechanical dehydration after freezing. Fine ice crystals due to rapid freezing are
Reduce the drying speed, especially at the end of the drying process,
Therefore, the vacuum freeze-drying method was applied to frozen tofu products because it was considered to be a small amount of water for finished products, and because it was considered that simple vacuum freeze-drying would inevitably cause cracks and damage to dried tofu. Even attempts to do so were recognized as pointless. It is thought that the process operations of adjusting the finished moisture, non-oxidative freezing, use of carrageenan, and reducing the size of the processed product have a synergistic effect on preventing cracks in the dried finished product. It should be noted that the manufacturing method of the present invention is not economically disadvantageous in terms of the entire process.

Claims (1)

[Scope of Claims] ω A tofu snack containing a freeze-dried product of soybean milk gel as a main component, having a small apparent specific gravity, a dense porous structure, and a property of melting in the mouth. ■ The first step of producing soy milk gel from soybeans and molding it into any desired size or shape, immersing or soaking the formed soy milk gel or tofu in an aqueous carrageenan solution, an aqueous sweetener solution, or an aqueous seasoning solution. A method for producing tofu snacks, which comprises a third step of producing the final product without using a coating material by quickly freezing the tofu and reducing the temperature to 12'0 - 40°C.