JPS5836350A - Making of raised food product by rapid frying in oil under reduced pressure - Google Patents

Abstract

PURPOSE:A food product whose body temperature is uniformly kept at a certain level is fried in oil under reduced pressure to effect uniform dissipation of water at every part, thus shortening the time for drying the food product and preventing its damage as well. CONSTITUTION:A food product is uniformly heated in the temperature-adjusting chamber 36 kept at such a prescribed temperature as the water in the product vaporizes and dissipates but does not boil, and simultaneously the inside of the vacuum chamber 21 is kept at such a low pressure as the boiling point of water in the chamber becomes lower than the body temperature of the food product. Further, the oil in the oil tank 22 is heated with heater 26 up to a prescribed temperature higher than at which the water in the food product vaporizes off. Under these conditions, the food product is fed through conveyor 37, hopper 38, lock valve 39 and conveyor 23 into the oil, fried and dried. The dried food product is sent through hopper 40, conveyor 41, 42 and lock valve 43 to the outside.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides puffed foods using a rapid vacuum deep-frying method that dries foods approximately evenly, shortens the drying time, and reduces food quality deterioration such as damage caused by heat during drying. Relating to a manufacturing method.

Conventionally, there are various methods for drying foods, such as hot air drying, microwave drying, freeze drying, vacuum drying, and deep-frying. There is a law.

The method of the present invention attempts to solve the drawbacks of the above-mentioned drying method of deep-frying under internal pressure, and the conventional vacuum deep-frying method has the following drawbacks.

In other words, in the conventional vacuum deep-frying method, the food to be dried is placed in a vacuum deep-fried equipment containing oil at a temperature higher than the temperature of the food, and the food is heated from the outside by the heat of the oil in the vacuum deep-fried equipment. , drying is carried out by raising the temperature of the product to the boiling point of water. However, ＼
In this method, the temperature of the food is raised by the temperature of the oil, so it is not possible to quickly equalize the temperature between the surface and inside of the food to be dried. As a result, the surface temperature of the food first reaches the boiling point of water, and water evaporation begins from this area, but the internal temperature has not yet reached the boiling point of water, so no water evaporation or water diffusion occurs. This will result in an imbalance. Therefore, as drying progresses, the surface of the food becomes dry and solidified, making it increasingly difficult for internal water to diffuse or evaporate. Become a woodcutter that must be soaked for an hour. As a result, not only the surface of the food becomes scorched, but also it becomes difficult to dry the food uniformly. This phenomenon becomes more noticeable as the thickness of the food to be dried increases.

The present invention aims to solve the drawbacks of the conventional vacuum deep-frying method, and its basic principle is to evaporate or diffuse moisture in each part of the food approximately evenly when drying the food by deep-frying. It consists in tightening.

The gist of the method of the present invention, which was completed based on this basic principle, is that after the entire food is temperature-controlled to an approximately uniform temperature, water evaporates at a rate at which the food expands and at a temperature lower than the food temperature. This is a method for producing puffed foods using a rapid vacuum deep-frying method for foods, which is characterized by bringing the food into a rapid vacuum state where the pressure is reduced to such an extent that the product temperature is almost the same as that of the product, frying in oil having a temperature approximately the same as that of the product, and then returning the food to normal pressure. .

The food to be subjected to the method of the present invention is a solid food such as vegetables, fruits, grains, legumes, or dough formed mainly from grains, and the thickness of the solid food is adjusted to about 20 mm or less. It is preferable to effectively achieve the object of the present invention. These foods are foods that can be expanded by evaporating moisture according to the method of the present invention.

In the present invention, these solid foods are first subjected to temperature control treatment. degree. , temperature control processing and 4-day meal. The goal is to make the temperature of each part' approximately equal. The method is not particularly limited, and may be carried out by any suitable means such as hot air treatment, steaming treatment, constant temperature constant temperature treatment, etc. However, considering that the drying means of the method of the present invention is deep-frying, A means of doing so is preferable.

The temperature control processing conditions need to be below the temperature at which water in the food evaporates. If the temperature is higher than the temperature at which water evaporates, then drying has already begun on the surface of the food, which causes a solidification phenomenon on the surface, so that even if the subsequent processing is carried out by the method of the invention, the object of the invention cannot be achieved. may not be able to be achieved. Therefore, as the temperature condition for the temperature control treatment of food in the method of the present invention, it is preferable to set the temperature at a temperature at which water does not evaporate and close to the water evaporation temperature. Thus, it is possible to dry foods even if the degree of vacuum is low, or by increasing the degree of vacuum, it becomes easier to obtain foods with a high degree of puffiness.

After straining in this manner to bring the temperature of the entire food to approximately the same level, immediately reduce the pressure so that the boiling point of water is lower than the temperature of the food above, and in that state bring the temperature to approximately the same level as the temperature of the food. It is fried in oil containing K.

1. In this process, the principle of drying is as follows. Naturally, if the atmosphere is reduced in pressure in the presence of water, the boiling point of water will be lowered, but in the present invention, the boiling point of water is lower than that of the temperature-controlled product i. When the food is placed in such a reduced pressure state, the water in the food is already at a temperature higher than the boiling point of the water. immediately becomes vaporized, and the moisture in the surface layer of the food quickly evaporates, while the moisture in the center of the food quickly diffuses to the surface layer and then evaporates. The moisture in the food evaporates or diffuses because the food is dried in a relatively short period of time while the temperature of the food remains low through the temperature control process.

In this process, the means for placing the food in a reduced pressure state such that the boiling point of water S is lower than the temperature of the food can be broadly classified into the following two methods.

One method is to control the temperature of food in an oil tank (in which the temperature of the food is controlled) and then rapidly reduce the pressure in the entire oil tank. The other method is to control the temperature of the food using a separate method and then feed it into an oil tank that has been previously reduced in pressure.In the former case, the temperature control and deep-frying of the food can be done in the same container. 0 advantages and no fluctuation in food temperature after temperature control processing G) and l, N
Utilizing force S, the force S rapidly depressurizes the atmosphere of the container! !
11 Scraping 8 Climbing blade 1 A pressure reducing means force S having a relatively large capacity is required.

On the other hand, in the latter case, the atmosphere in the oil tank is brought to a reduced pressure state 1 in advance, so a depressurizing means with a capacity as large as that on the left is not required. It is necessary to transfer the oil into the tank.
As a result, not only is it necessary to charge two or more types of food, but also the temperature of the food tends to be uneven during transportation to the oil tank after the temperature control process.

Considering the above, the former method is preferable as a means to achieve the purpose of the method of the present invention, and in this case, the time to reduce the pressure in the oil tank is within 3 minutes after temperature adjustment treatment. Furthermore, it is desirable to achieve the desired reduced pressure within one minute.

If the time required to reduce the pressure in the oil tank increases, the food in the oil will gradually dry from the surface layer, resulting in a longer frying time and an increase in oil absorption. Furthermore, disadvantages such as reduced swelling are present.

Next, in the above-mentioned deep-frying process, it is important that the temperature of the oil for frying the food is approximately the same as the temperature of the temperature-controlled food. This makes it possible for each part of the food to be dried approximately evenly.

In the conventional deep-frying method, when food is immersed in heated oil, the surface layer of the food quickly rises to the oil temperature and is dried, but the temperature of the center layer of the food rises more than the surface layer. The slower the drying time, the longer it will take to dry. As a result, each part of the food becomes unevenly dried, and this results in a phenomenon in which different parts of the surface layer of the food are unevenly scorched. This phenomenon becomes more pronounced as the temperature difference between the oil temperature and the food temperature increases. On the other hand, in the method of the present invention, the temperature of the food and the temperature of the oil are kept approximately at the same level, so the temperature of the surface layer and the center layer of the food changes with almost no difference in temperature. It will be dried approximately evenly. As described above, in order to achieve the purpose of the method of the present invention, there is an important correlation between the food temperature and the oil temperature.

The food fried in the manner described above is returned from the reduced pressure atmosphere to the normal pressure atmosphere by appropriate means, and then transferred to a seasoning process, filling 11, packaging process, etc. as required.

In the above-mentioned deep-frying process, when the food is almost completely fried and dried, the oil temperature may be raised to fry the food, thereby imparting a desirable color and aroma to the surface of the food. In this case, the food is fried and dried almost evenly, so even if the oil temperature is raised afterwards, the surface of the food will be heated almost uniformly, and as a result, there will be almost no uneven heating as in conventional methods. .

Each part of the fried tofu food obtained in this way is dried approximately evenly, and when the fried tofu food is eaten as a snack, it has a roughly uniform texture, or it can be used as instant noodles. When eating ingredients such as ingredients for instant noodles, which are reconstituted with hot water or the like, the reconstituted ingredients can be almost uniformly reconstituted.

Further, according to the method of the present invention, it is possible to expand the food product by low-temperature processing, and it is possible to suppress the quality deterioration of the food product due to heat as much as possible. Moreover, it is now possible to obtain puffed products of foods that could not previously be puffed at low temperatures, such as onions and bananas, as well as other foods such as cabbage, carrots, etc.
By applying the method of the present invention to apples and the like, we have succeeded in obtaining puffed foods with textures that have never been seen before. As a result, a wider variety of foods can be puffed than with conventional deep-frying methods.

FIGS. 1 and 2 now show examples of apparatus which may be used for carrying out the method of the invention. Hereinafter, a specific apparatus for carrying out the method of the present invention and an example of its use will be explained based on FIGS. 1 and 2.

FIG. 1 is a schematic diagram showing a specific example of a batch type device.

The oil tank 1 is equipped with a lid 2 that can seal the inside of the oil tank.

Furthermore, a retainer 3 with a mesh-like lid is provided inside the oil tank 1, and a support 4 with an uneven shape is provided at the end of its side surface, and the support 4 and a gear 5 are meshed with each other and are connected to the gear 5. By rotating the handle 6, the gear 5 rotates, and the retainer 3 moves up and down accordingly. A circulation pipe 9 is connected to the side wall of the oil tank 1 via a pump 7 for circulating oil in the oil tank and a heater 8 for heating the oil. In addition, a temperature sensor 10 is installed in the oil tank l to measure the oil temperature.
The temperature sensor 10 and the heater 8 are connected via an oil temperature controller 11 to adjust the oil temperature. Also, the other side wall l of the oil tank 1
A vacuum pump 12, a cold trap 13, and a valve 14 are connected to this via a piping 15, whereby the inside of the oil tank 1 is brought to a desired degree of reduced pressure. The valve 14 is connected to a vacuum gauge 16 installed on the lid 2 via a vacuum regulator 17, thereby adjusting the degree of reduced pressure in the oil tank 1.

To use the above device, first open the lid 2 of the oil tank 1, turn the handle 6 to lift the retainer 3 above the oil surface, open the lid of the retainer 3, and place the food to be fried into the retainer. Close the lid of the hindlimb retainer 3 stored in the container. During this time, the oil in the oil tank 1 is circulated through the circulation pipe 9 by the pump 7 and heated by the heater 8 to a desired oil temperature (however, it is below the temperature at which water evaporates). After that, the handle 6 is rotated to immerse the retainer 3 in the oil, so that the temperature of each part of the food in the retainer 3 is approximately equal.
Maintain this condition until the temperature is controlled. During this time, the oil is maintained at a constant temperature by the temperature sensor 10, oil temperature controller 11, and heater 8.

Oil temperature adjustment continues until the food is fried. Next, when the temperature of each part of the food in the retainer 3 reaches approximately the same level, the lid 2 of the oil tank 1 is closed, the valve 14 is opened, and the vacuum pump 12 is operated to immediately reduce the atmosphere in the oil tank 1 to water. The pressure is reduced so that the boiling point of
4 to adjust the degree of pressure reduction of the atmosphere inside the oil tank 1. Steam generated during frying is condensed by a cold trap 13 and discharged. After frying, the handle 6 is rotated to lift the retainer 3 above the oil surface, and after returning the inside of the oil tank 1 to normal pressure, the lid 2 is opened and the fried food is taken out from the retainer 3.

FIG. 2 is a schematic diagram showing a specific example of a continuous type device. 4
indicates a vacuum chamber, and oil cypress wood is installed inside. The oil tank n is provided with a net conveyor n, 24 for frying and transporting foods. Also oil tank η
A circulation pipe n is connected via a pump 6 for circulating oil from the bottom to the side surface and a heater for heating the oil. The heater I is connected to the oil temperature controller 9.1. A temperature sensor installed at the bottom of the oil tank n is connected to the bottom of the oil tank, thereby regulating the oil temperature. The side wall of the vacuum chamber 21 is connected to a pipe (by means of a vacuum pump I).

A cold trap 31 and a valve are connected, thereby creating a desired degree of vacuum in the vacuum chamber 21. Further, the valve [ is connected to a vacuum gauge stem installed at the upper part of the vacuum chamber 21 via a vacuum electric regulator, and the degree of reduced pressure in the vacuum chamber 21 is adjusted. Further, a temperature-controlled processing chamber % is provided in the upper part of the vacuum chamber 21, and a conveyor 37 for conveying food and a hopper (for supplying food to the vacuum chuck 21) are installed inside the chamber. An air valve 39 is provided at the tip of the hopper in the chamber 21.Furthermore, at the bottom of the vacuum channel 21, there is a hole ξ-42 and an air valve 43 for discharging fried foods. The fried food is placed in a vacuum chamber, <-21
The hopper 40 and hikkon bearer 41 inside
e-42.

When using the above-mentioned apparatus, food is first temperature-controlled in a temperature-controlled processing chamber. During this time, the inside of the vacuum chamber (-21) is brought into a reduced pressure state using a vacuum pump concave so that the boiling point of water is lower than the food temperature. The oil is circulated by the pump 6 and heated by the heater to the desired oil temperature (but below the temperature at which water evaporates). The hot-processed food is supplied by the conveyor 37 to the top of the net conveyor in the vacuum chamber 21 through the main compartment and air tank valve guide.
Immediately thereafter, it is guided into oil by a net conveyor n, 21 and fried with a force>jl. Foods that are fried in tofu are no good! It passes through a, is supplied to the conveyor 41, passes through the air hole ξ-42, and the airlock valve 43, and is discharged. Vacuum chamber during the above process, reduced pressure within <-21+tit
It is regulated by a vacuum gauge M, a vacuum degree controller, and a valve °C, and the oil in the oil tank n is maintained at a constant temperature by a temperature sensor, an oil temperature controller 6, and a heater.

Example 1 Nana chips were obtained in the following manner using the T apparatus shown in FIG.
After heating the oil in the oil tank 1 to 95°C, the handle 6 is rotated to position the retainer 3 above the oil level. Next, put 200 sliced bananas into the retainer 3, cover the retainer 3, and then rotate the handle 6 to immerse the retainer 3 in the oil, maintaining the oil temperature at 95°C. The temperature of each part of the banana is brought to 95° C. by holding the temperature for 5 minutes. After that, close the lid 2 and close the valve 1.
Open 4 and operate the vacuum pump 12 to reduce the pressure f in 50 seconds.
After reducing the temperature to 1 torr, deep-fry under reduced pressure for 15 minutes. During this time, the oil temperature was 95℃ according to the oil temperature controller 11.
The degree of vacuum in the sealed oil tank 1 is automatically maintained at 1 torr by the vacuum regulator 17.
is maintained. After frying under reduced pressure, the handle 6 was rotated to pull up the retainer 3 from the oil, and after draining the oil, the inside of the oil tank 1 was gradually returned to normal pressure, and then the lid 2 was opened and the banana chips were taken out from the retainer 3. The obtained banana chips had a pleasant puffed, crunchy texture.

Instant noodles were obtained by the following method using the apparatus shown in Figure 1.

First, the lid 2 is opened, and the oil in the oil tank 1 is heated to 100° C. by the heater 8, and then the handle 6 is rotated to position the retainer 3 above the oil level. Next, steamed noodles 2301 obtained in advance by a conventional method are placed in the retainer 3, and the retainer 3 is covered with a lid.The handle 6 is rotated to immerse the retainer 3 in oil, and the oil temperature is set to 100°C. The temperature of each part of the steamer was brought to 100° C. by maintaining the temperature for 8 minutes. Thereafter, the fi2 is sealed, the valve 14 is opened, and the vacuum pump 12 is activated to reduce the pressure to 1j4 torr in 40 seconds, and then fry the tofu under reduced pressure for 5 minutes. During this time, the oil temperature was adjusted to -10 by the oil temperature controller 11.
Automatically maintained at 0°C.

After that, with the oil still immersed, reduce the oil temperature to 120℃ for 3 minutes.
℃ and maintained that state for 2 minutes to complete the vacuum frying. During this time, the degree of reduced pressure in the sealed oil tank 1 is maintained at reduced pressure f4 tart by the vacuum degree regulator 17.

After the vacuum frying is complete, rotate the handle 6 to remove the retainer 3.
After pulling the noodles out of the oil and gradually returning the pressure inside the oil tank 1 to normal pressure, the lid 2 was opened and the fried noodles were taken out from the retainer 3. The obtained fried noodles had a preferable pale yellow color, and could be reconstituted with boiling water in a shorter time than conventional instant noodles, making them excellent instant noodles.

[Brief explanation of the drawing]

Figures 1 and 2 are schematic diagrams of equipment that can be used to carry out the method of the present invention, and Figure 1 shows an example of a batch type equipment.
FIG. 2 is a schematic diagram showing a specific example of a continuous type device. 1... Oil tank, 2... Lid, 3... Retainer, 4...
・・Strut, 5・・Gear, 6・・Handle, 7・・Pump, 8・・Heater, 9・・・Circulation lξ Eve, 10・・
・Bedness sensor, 11... Oil temperature controller, 12... Vacuum pump, 13... Cold trap, 14... Valve, 15... Piping, 16... Vacuum needle, 17... Vacuum level controller, vacuum chamber, oil tank, 27, circulation, public 11 sensor, oil temperature controller, I... vacuum Pump, 31...
・Cold trap, proverb...valve,...piping,
A...vacuum needle, A--true 9F controller, I...temperature control room, line...conveyor, holder...hopper, fan...
Air lock valve, Tochi... Hola, z-141... Conveyor, 42... Hopper, 43... Air lock valve Patent applicant House Foods Industry Co., Ltd. Agent Michi Goto Document of amendment to student proceedings Patent Office Chief Justice Kazuo Wakasugi 1, Indication of the case 1984 Patent Application No. 184268 2, Title of the invention Rapid vacuum deep-frying is a method for producing puffed foods according to the law 3;
Relationship with the case of the person making the amendment Patent applicant 4, attorney 〒104 6, Number of inventions increased by the amendment O The following statement is written after “It becomes easier” written in the 5th line of page 5 of the specification. insert. "If the temperature control process of the present invention is carried out under pressure, the temperature of the food can be raised to 100°C without causing any drying of the food.
Coloring to food because it is enhanced more than that. Adding fragrance can be expected to have the same effect as (2) II. Furthermore, according to the pressure-adjusted mixing process, the drying efficiency of the food is high when the pressure is reduced, and a uniform and larger degree of puffing can be obtained. ”

Claims (1)

[Claims] After controlling the temperature of the entire food to approximately the same temperature, the food is rapidly depressurized to the extent that water evaporates at a rate at which the food expands and at a temperature lower than the product temperature, and the temperature is approximately the same as the product temperature. A method for producing a puffed food using a rapid decompression deep-frying method, which is characterized by frying in oil with varying temperatures and then returning the pressure to normal pressure.