JPH0420580B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel method for producing soybean foods.

As a processed soybean product, roasted peanut-style fried soybeans, which are made by frying soybeans swollen with water, boiling water, etc., and seasoning as necessary, have been known. This product has an average moisture content of about 2 to 5%, is crunchy, and is popular as an affordable snack food. By the way, such products are usually in the form of whole soybeans with the skin attached, or in the form of half-split soybeans with the skin removed, that is, in the form of soybean cotyledons. Among these, the latter has the advantage of having an excellent texture when eaten because it does not have a skin, and is considered to be more preferable. However, the reality is that the quality of this half-split product is questioned depending on the degree of cracking on the half-split surface. The present applicant previously filed a patent application in 1983 with the problem of how to reduce the degree of cracking.
No. 20443 was filed in 2013, and an improved method for producing conventional fried soybeans was proposed. However, even with this improved method, the cracking rate could only be reduced to around 20% at most.

Under these circumstances, the present inventor attempted to solve this problem from a completely different perspective, and found that soybeans with almost no cracking on the half-split surface, or with a cracking rate of less than 5% even if there were, We have developed a new method for producing foods, leading to the present invention.

The present invention provides a method for producing a soybean food, which comprises subjecting soybeans to swelling heat denaturation and then adjusting the average moisture content to within 8% by freeze-drying.

The soybean food obtained by the method of the present invention is denatured by swelling heat. Here, swelling means that the volume is increased by some means compared to the volume of the raw soybean (dry content). 1.5 of the size of the original soybean
Preferably, the size is about 2.0 times larger.
Further, thermal denaturation means that the substance is solidified by heat and can no longer be liquefied. Soybeans in such a state have not only lost the green taste of the raw soybeans, but also have improved digestibility compared to the raw soybeans.

The soybean food obtained by the method of the present invention further has an average moisture content of 8% or less. If the average moisture content exceeds 8%, the product will have a damp and soggy texture, which is undesirable in terms of texture. 2% moisture content
Generally, 2 to 8%, preferably 2
It is about 5%.

In addition to having the above-mentioned properties, the soybean food obtained by the method of the present invention has a major feature in that the cracking rate is within 5%. Here, the crack rate means the ratio of cracked products to the total half-broken products, expressed as a percentage, when cracks with a length of 3 mm or more on the half-broken surface of half-broken products are considered cracked. . In addition, the external curved surfaces of the soybean food obtained by the method of the present invention other than the half-split surface are smooth as a whole, and it is difficult to notice any partial defects on the external surface.

Hereinafter, the method for producing soybean foods of the present invention will be explained in detail.

The soybean raw material used in the present invention may be either raw soybeans with skins or raw soybeans that have been dehulled to have no skins.

The above-mentioned soybean raw material (dry product) is first heat-denatured in a state in which it is swollen to its original size.
Swelling is usually done by allowing the soybeans to absorb water, and the size is approximately 1.5 to 2 times the original volume (this is approximately 1.5 to 2 times the original weight).
(equivalent to 2 times). Swelling weakens the soybean structure, which can impart a soft feel to the final product. If the degree of swelling is too small, it will be difficult to impart such a soft feel. On the other hand, if the soybean swells too much, it becomes brittle and tends to collapse, especially when the skin is mechanically removed after swelling. The water used for swelling may be in liquid or vapor form; in the former case, it may be cold water, hot water or hot water.

The above-mentioned "thermal denaturation in a swollen state" includes not only the case where the swollen state is then heat denatured but also the case where swelling and heat denaturation are carried out simultaneously. In view of workability, it is preferable to carry out swelling and heat denaturation simultaneously. in this case,
The treatment is carried out by soaking or steaming the soybeans in hot water. When soaking in hot water, it is usually 2 to 5 times the amount of soybean raw material used in hot water of 80 to 120℃.
10 to 80 minutes, as a specific example, 80 minutes at 88℃,
All you need to do is heat it, and when steaming it, it is usually 80~
Heating with steam at 120°C for 15 to 90 minutes will achieve the above purpose. In addition, when raw soybeans with skins are used as the soybean raw material, dehulling treatment is incorporated in the initial step of the heat swelling treatment described above, and then the dehulled and roughly halved soybeans are heated again to undergo swelling heat denaturation. It is good to achieve this. This is preferable because soybeans are less likely to be crushed even if the soybeans are mechanically dehulled.

The soybeans thus swollen and heat-denatured are then freeze-dried to an average moisture content of 8% or less. In this process, the above-mentioned soybeans are frozen and then dried. Usually, freezing is carried out at -20 to -40°C for 1 to 10 hours, and drying is carried out at 1 to 0.05 Torr for 5 to 10 hours. This can be done under the condition of 20 hours. In addition, these conditions may be adjusted as appropriate to keep the average water content within 8%.

The soybeans that have been freeze-dried in this way to have an average moisture content of 8% or less have cracks on their half-split surfaces, probably because dehydration due to freeze-drying proceeds slowly, unlike dehydration through conventional deep-frying. The cracking rate is almost never observed, and the cracking rate is within 5%, and is usually substantially close to zero.

In addition to having the above-mentioned shape characteristics, freeze-dried soybeans have the same size as conventionally fried soybeans that have been dehydrated and dried by deep-frying. Unlike the soybeans, which have been shrunk to about 2/3, there is virtually no shrinkage due to freeze-drying, and the soybean remains almost swollen, i.e., about 1.5 to 2 times the size of the original soybean (dry product). It maintains its size. The specific gravity of this thing is 0.6
It is smaller, usually around 0.55. Therefore, the internal structure of soybeans before freeze-drying is porous, and this porous structure is thought to be the reason why the final product has a crispy and soft texture.

The soybean food obtained by the method of the present invention is the soybean food as described above, but this food may be further seasoned, for example, by using freeze-dried soybeans as described below. Seasoning methods include attaching or absorbing salt and other seasonings to the surface,
For flavoring with oil, use an appropriate method, such as coating with oil by spraying or dipping, or seasoning with seasonings as needed after coating with oil in this way. can be mentioned. In addition to imparting an oily flavor, oil coating also has a moisture-proofing effect, so it can be said to be appropriate for purposes such as preservation. As the coating oil, lauric fats and oils having antioxidant properties are preferable, and examples thereof include coconut oil, palm kernel oil, and the like. An example of a coating method is 150~220℃ oil.
Oil-coated foods can be prepared by soaking them for about 10 minutes.

The soybean food obtained by the method of the present invention as described above can not only be used as a completely new snack food instead of conventional fried soybeans, but also can be used as it is or further when used as sprinkles for salads. Even if it is coarsely crushed or crushed as appropriate, it will be soft, meaning that even if you eat it with a soft salad, it will not be as crunchy as traditional furikake made from fried soybeans, so it will not give a strange feeling. It is something that can provide what is not available.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 1 kg of raw soybeans with skins (dry product) was immersed in 95°C hot water containing 10 g of baking soda for 5 minutes to swell the surface of the soybeans, then taken out of the water and dehulled using a roll method. I tried to remove the skin by passing it through a machine. This dehulled soybean was further soaked in hot water at 85℃ for 40 minutes.
After heating and holding for a minute, the water was drained to obtain a swollen heat-denatured soybean that was approximately 90% half-split. The weight of this soybean had become approximately 2 kg due to absorption of water, and it had swollen to approximately twice the size of the original raw soybean with skin.

The thus obtained swollen heat-modified soybeans were kept in a freezing chamber at -40°C for 3 hours to freeze them, and then kept in a freeze dryer at 0.1 Torr for 12 hours to obtain freeze-dried soybeans (moisture 4%).

As a control, swollen heat-denatured soybeans produced in the same manner as above were exposed to hot air at 75°C for 20 minutes, air-dried, and then fried in coconut oil at 190°C for 4 minutes.
A control fried soybean was produced.

Next, the occurrence of cracks on the half-cracked surfaces of the half-cracked products of the present invention and the control product were observed, and the results were as follows.

Crack rate Product according to the present invention: 0% Fried soybean as a control: 18% When the texture of both was further examined, the product according to the present invention was crispy and soft, but
The control product was crunchy, crispy, and hard.

Example 2 The present invention was carried out in the same manner as in Example 1 above, except that when the soybeans after dehulling were thermally denatured by swelling in hot water 3 at 85°C, this hot water contained 3% by weight of salt. Salted freeze-dried soybeans of the invention were obtained.

Next, this product was immersed in coconut oil at 180℃ for 5 minutes to form an oil-coated food (moisture 3
%).

Example 3 While still hot, the product prepared according to Example 2 above was mixed with 3% of its weight of powdered spices of onion, garlic, and pepper to produce three types of the present invention. Got seasoned food.

Claims (1)

[Claims] 1. A method for producing a soybean food, which comprises subjecting soybeans to swelling heat denaturation and then adjusting the average moisture content to within 8% by freeze-drying.