JPS62195244A - Production of dried food - Google Patents

Abstract

PURPOSE:To obtain a dried food having the flavor, color and appearance of raw material and giving crispy and soft feeling to the palate, by subjecting a raw material to be dried to various treatments such as trimming, shaping, blanching, etc., slowly freezing the treated material and frying in oil under reduced pressure after thawing. CONSTITUTION:A raw material to be dried (e.g. raw sweet potato) is subjected to various treatments such as trimming, shaping, blanching, etc., at need and slowly frozen in a freezer at -20 deg.C for 15hr. The frozen material is thawed by leaving in a room temperature atmosphere, immersed in a solution of sugar, starch, protein, etc., at need, put into a vacuum frier furnished with a basket- type centrifugal deoiling apparatus, evacuated to <=20Torr with a vacuum pump and fried in an oil under reduced pressure by supplying the frier with an oil or fat of 70-90 deg.C. The objective dried food having a water-content of <=5% can be produced by this process.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing a dried food, and more particularly to a method for producing a dried food by subjecting the food to be dried in a frozen state to vacuum oil pumping.

The dried food obtained by the present invention has the original flavor, nine colors, and appearance of the raw materials, has a crispy and soft texture, and has the property of absorbing water and restoring itself in boiling water in a short time. Because of the snacks.

It is useful as a delicacy or as an ingredient in soups and noodles.

[Prior Art] Foods dried by the vacuum deep oil method are dehydrated and dried in oil at a relatively low temperature, that is, 70 to 130°C, and under reduced pressure. It retains the original flavor and color of the raw materials, and has the ability to produce products with a porous, slightly expanded structure. This dried product has better color tone, flavor, appearance, and resiliency than hot air-dried products, and has a more solid structure than freeze-dried products.
It is hard to break, has a unique flavor derived from oil, and has excellent color tone, appearance, and restorability.

For this reason, the preparation of dried foods using the vacuum deep oil method has recently been attracting attention, but its basic principle has been known for quite some time, with literature dating back to the 1330s, and related patent applications. It's been happening a lot lately.

However, from the standpoint of product quality, industrial manufacturing methods, etc., conventional methods cannot be said to fully utilize the basic principles, and improvements have been made only rarely.

To describe the problems of the conventional technology in detail, the raw materials used for drying have a unique tissue structure, and even if the raw material is the same, there are differences depending on the part of the tissue itself and individual differences. It is not possible to obtain a product that has a crunchy texture and does not have sufficient resiliency when immersed in boiling water. It is hard and difficult to eat as a snack or delicacy. Furthermore, the reconstitution properties are also inferior to those of freeze-dried products.

As a way to solve these problems, it has been proposed to reduce the thickness of the raw material to be dried to make it easier to dry, but this method does not provide a satisfactory effect. A method of immersing in a solution of starch, protein, gum, etc. and a method of adjusting the vacuum oil depth conditions, that is, oil temperature and degree of vacuum, have been proposed, but these methods are only partial improvements. Although it has been proposed to adapt the method to other drying methods, the results have not been sufficiently satisfactory.

[Problems to be Solved by the Invention] Therefore, the problems to be solved by the present invention are as follows.

■ To obtain a product that has the flavor, nine colors, and appearance unique to the raw materials to be dried, especially a product that does not shrink or deform in appearance and has a shape similar to that before drying.

■ To obtain a product with crispy and soft texture.

■ To obtain a product that absorbs water and restores itself in a short time when immersed in hot water.

[Phase]) To obtain a product having the above-mentioned properties with a thickness of about 5 to 10m. [Means for solving the problems] The purpose of the present invention is to overcome all the problems as described below. An object of the present invention is to provide a method for producing dried foods.

That is, in the present invention, the raw material to be dried is subjected to treatments such as trimming, shaping, and blanching as necessary, then slowly frozen, then thawed, and added with sugar, powder, protein, etc. as necessary. This is a method for producing dried foods, which is characterized by immersing them in a solution under reduced pressure and then submerging them in oil under reduced pressure.

In the present invention, slow freezing is used to adjust the structure of the raw material to be dried so that moisture can be easily volatilized from the surface and structure of the raw material, and the raw material is then immersed in vacuum oil. In this case, in the early stage of drying, that is, until the moisture content of the water-mixing agent is 7 to 20%, the drying agent is dried in a relatively high temperature oil, usually oil at a temperature of 90 to 130°C, in a very short period of time. Stabilize the structural structure of the raw material so that it does not deform or shrink. Next, dry the raw material in oil at a relatively low temperature, usually at a temperature of 70 to 90°C, to retain as much of the original color, flavor, nutrients, etc. as possible of the raw material to be dried. Moisture content 415% without change or loss
It is important to dry the product to below F.

The present invention will be explained in detail below.

A wide variety of raw materials can be used as the raw material to be dried, such as vegetables, fruits, seafood, livestock meat, and cooked foods.

Specifically, vegetables include potatoes, sweet potatoes, carrots, root vegetables rich in fiber and starch such as lotus, bean sprouts, green beans, corn,
Preferably, mushrooms with a special tissue structure such as shiitake mushrooms are used.
Fruits with a high carbohydrate content such as apples, persimmons, and keelfish are preferred; seafood includes molluscs such as squid and octopus; meats with distinctive textures and structures such as clams, clams, and scallops are preferred; Foods such as beef, pork, and chicken are made of muscle fibers whose main component is protein, and cooked foods include meats such as shumai, dumplings, hamburgers, and meatballs, vegetables, and starchy foods. Some have unique structures.

The raw materials listed above are trimmed as necessary by removing inedible parts, peeling, and pulverizing, and blanching to deactivate enzymes.
Steaming to gelatinize the starch, immersion in seasoning liquid to add flavor, etc. are performed as appropriate.

Next, the surface and tissue of the raw material to be dried can be dried using a microscopic method, a contact freezer method, or a method using liquid carbonic acid or liquid nitrogen, depending on the properties of the raw material to be dried and the final quality required for the dried product. It is preferable to perform the freezing process slowly and completely over a period of 5 to 15 hours, thereby generating fine ice crystals on the surface and structure of the raw material to be dried. Next, the frozen product is thawed again at room temperature or under heat to melt the ice crystals formed in the structure of the raw material to be dried.

Create a porous tissue structure.

The freeze-treated and thawed product of the raw material to be dried thus obtained is immersed in a known solution of saccharides, starches, proteins, etc., if necessary. The purpose of this is to improve the drying yield, stabilize the structure, harden it, swell it, etc. Depending on the raw material, it can be used as an auxiliary means of the present invention. The dipping method is heating.
Various methods can be considered, such as normal pressure, pressurization, and reduced pressure; however, in the present invention, it is preferable to carry out the drying process under reduced pressure in order to allow the drying material to be adsorbed on the surface and into the structure of the material to be dried.

This prevents deformation and collapse of the tissue and enables processing in a short time.

The pretreated raw material to be dried thus obtained is dried in a drying process using a vacuum oil depth.

When selecting the vacuum oil depth conditions, it is important to dry the surface and porous structure of the raw material obtained by freezing as much as possible while preserving the original color tone and flavor of the raw material to be dried.

It is important to dry without changing or losing the nutrient a component, i.e., without deforming or shrinking the tissue structure of the dried thtI raw material, it is necessary to dry it until it is stabilized.
Then, it is necessary to dehydrate as instantaneously as possible until the moisture content reaches about 7 to 20 layers, that is, during the careful drying period. Therefore, relatively high temperature, generally 90-130
It is necessary to dehydrate in the temperature range of ℃ and under high vacuum. in this case.

The degree of reduced pressure is set to 50 Torr or less, preferably 20 Torr or less at the time of maximum moisture evaporation. The moisture content of the raw material to be dried is 7
Dehydration over a relatively long period of time until it reaches approximately 20% has the disadvantage that the tissue structure of the dried raw material itself tends to shrink and deform, and the advantages of freezing cannot be fully utilized. It is not possible to achieve the desired effect.

When the moisture content reaches a level of about 7 to 20 layers or less, the rate of volatilization of moisture from the raw material to be dried slows down, which is the so-called lapse rate drying period. In this region, the oil temperature is more directly affected than the drop in product temperature due to the latent heat of vaporization of water, and the temperature effect is IQ￥h.
becomes. Therefore, in this region, it is necessary to dry at a relatively low temperature, generally 70 to 90°C. If the temperature is below 70°C, the rate of moisture volatilization is slow and it is not efficient; if the temperature exceeds 90°C, raw materials containing a lot of sugar and amino acids are likely to brown, and the original color and flavor of the raw material to be dried will be retained. In addition, the drying end point selection window is narrow, leading to scorching, which increases the quality difference of dried products.

On the other hand, although the degree of reduced pressure is preferably as low as possible, it is necessary to maintain it at 50 Torr or less, preferably 20 Torr or less, at the time of maximum moisture evaporation. If it is outside this range, the advantage of the freezing effect of the raw material to be dried cannot be fully utilized, and the shrinkage and deformation of the structure of the raw material to be dried will be significant.
It is remarkable in the case of 10 layers.

[Example] Next, the present invention will be explained by examples.

Example 1 After washing 30 kg of raw potato (crystalline No. 14), it was sliced with a slicer to a thickness of 7.5 layers, and then placed in boiling water and blanched for 3 minutes. 2
It was frozen by placing it in a freezer at 0°C for 15 hours. After freezing, let it stand at room temperature for 5 hours to thaw, then put it in a vacuum depth device with a basket-type centrifugal deoiling device and heat it to 15 Torr with a vacuum pump.
Next, the pressure was reduced to
(vegetable oil) 4001) was sent by pump. Delivery time is 1 minute! It was 5 seconds. In addition, the degree of depressurization rose to 20 Torr at one point 2 minutes and 15 seconds after the start of oil supply;
After a few minutes, the pressure decreased to 15 Torr and became stable. The oil temperature dropped to 85°C 6 minutes and 30 seconds after the start of oil delivery. Oil whose temperature was adjusted to 85° C. was circulated in the oil source device 6 minutes and 30 seconds after the start of oil delivery, and the oil was discharged 17 minutes and 30 seconds after the start of oil delivery.

Thereafter, the oil was removed by centrifugation at 90 rpm for 2 minutes, and after releasing the vacuum, the dried sweet potatoes were taken out. In this way, 11.5 kg of dried slices with a moisture content of 3.9% were obtained.

This product had no shrinkage or deformation in appearance, had a bright color, and had a crispy and soft texture when eaten as is. Furthermore, when this product was immersed in hot water for 3 minutes and then drained, it almost absorbed water, was restored, and had the same flavor and texture as before drying.

Example 2 After washing 35 kg of key raisins with water, the slices were sliced into 10-layer intestine-thick slices using a slicer, and then placed in a freezer at -20°C for 10 hours to be frozen. After freezing, the temperature of the solution was adjusted to 25-30°C (starch hydrolyzate 20%, vitamin CG, 05%).

After soaking in 80 kg (containing 0.2% fragrance) for 3 hours, the liquid was drained. This was placed in a vacuum deep oil device equipped with a basket-type centrifugal deoiling device, and the pressure was reduced to 12 Torr using a vacuum pump. Then, 400 n of oil (melting point: 37°C, vegetable oil) at 115°C was pumped. The time required for delivery was 1 minute 20 seconds. The degree of vacuum increased to 18 Torr at 2 minutes and 45 seconds after the start of the oil delivery, but then decreased and stabilized at 10 to 12 Torr. Further, the oil temperature decreased to 79°C 5 minutes and 30 seconds after the start of oil supply. 5 minutes and 30 seconds after the start of oil supply, oil whose temperature was adjusted to 80℃ was circulated in the vacuum oil depth device, and the oil was discharged 15 minutes and 30 seconds after the start of oil supply. The oil was removed by centrifugation at 110 rpm for 3 minutes, and the dried keelai was taken out after releasing the vacuum. In this way, sliced dried kiwi with a moisture content of 4.2%8
．． I got 1.

The appearance of this dried product had no shrinkage or deformation, the color was bright, and when eaten as is, it had a crispy and soft texture.

Example 3 After washing 40 kg of shelled clams, they were boiled in 3% saline solution and heated for 3 minutes.Then, they were taken out, drained, frozen in a contact freezer, and then placed in a refrigerator (
It was thawed by standing at 7°C for one day and night. After cutting off the drip, it was placed in a vacuum depth device with a basket-type centrifugal deoiling device, and the pressure was reduced to 15 Torr with a vacuum pump. After that,
Oil at 130°C (melting point 37°C, vegetable oil) 400 f
was pumped in. The time required for delivery was 1 minute and 30 seconds. The degree of vacuum rose to -18 Torr 3 minutes after the start of the oil delivery, but then decreased and stabilized at lθ to 12 Torr. Also, 9 minutes and 30 seconds after the oil delivery started, the oil temperature was 89℃.
It declined to . 9 minutes and 30 seconds after the start of oil supply, the oil heated to 90°C for 31 minutes was circulated in the reduced pressure oil depth device, and 22 minutes and 30 seconds after the start of oil supply, the oil was discharged. Next, 110
After deoiling by centrifugation at 0 rpm for 2 minutes and releasing the vacuum, the dried clams were taken out. This way it retains moisture! □j: 3
, 8.8 kg of 9% dry clams were obtained.

The appearance of this dried product showed no shrinkage or deformation, and no change in color tone. When eaten as is, it had a crispy and soft texture. Furthermore, when this dried product was immersed in hot water for 3 minutes, it absorbed water and was restored to have a texture unique to clams.

[Effects of the Invention] The dried food obtained by the present invention has the flavor, color and appearance inherent to the raw materials, and has a crispy and soft texture. Furthermore, since this dried food has a porous tissue structure, it has the property of absorbing water and restoring itself in a short period of time when immersed in hot water. Therefore, dried foods can be eaten as-is as snacks or delicacies, and those that have been absorbed and reconstituted have a wide range of uses as ingredients for soups and noodles (ramen, udon, soba, etc.).

Claims (2)

[Claims] (1) Trimming and shaping the raw material to be dried as necessary.
After processing such as blanching, slow freezing is performed,
A method for producing a dried food product, which is then thawed, and optionally immersed in a solution of sugar, starch, protein, etc. under reduced pressure, and then poured into oil under reduced pressure. (2) The raw material to be dried is heated at an oil temperature of 90 to 130°C and a reduced pressure of 50 Torr or less at maximum water evaporation, preferably 20 Torr.
Claim 1: Drying to a moisture content of 8 to 20% under the following conditions, and then drying at an oil temperature of 70 to 90°C and a degree of vacuum of 20 Torr or less until a moisture content of 5% or less. Method for producing dried foods as described in Section 1.