JPH01269458A - Method and apparatus for frying under reduced pressure - Google Patents

Abstract

PURPOSE:To provide a fried puffy food having an excellent eating touch feeling by heating the food while a basket receiving the food is moved in the vertical direction between the space portion and heated oil in a frying vessel to maintain the basket in a wholly immersed state and in a semi-immersed state. CONSTITUTION:A food such as a vegetable, fruit or animal product is received in a basket 1 and subsequently introduced into a heated oil 8 in a frying vessel 2 under a reduced pressure. The food is fried for a constant time while the basket 1 is moved in the vertical direction between a wholly immersed state where the whole portions of the basket are immersed in the heated oil and a semi-immersed state where only the upper portion of the basket is exposed above the surface of the heated oil. The treated basket 1 is subsequently lifted above the oil to drain the oil from the food and further cooled with cold wind, etc., thereby performing the frying treatment of the food in a short time and efficiently.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a vacuum frying method and apparatus for frying foods such as various vegetables, fruits, marine products, livestock products, or molded products thereof under reduced pressure. It is related to.

[Prior Art] When producing fried foods by frying foods such as various vegetables, fruits, marine products, livestock products, or molded products thereof, the above-mentioned foods are generally cut into appropriate sizes. A method is adopted in which the basket is housed in a basket, and the basket is immersed in heated oil in a evacuated frying tank. However, for a while after starting flying, the food is heated under reduced pressure and suddenly releases a large amount of honho qi, and the rising force of this water qi and the buoyancy of the food cause the food to rise to the surface all at once. Because they are pushed against the lid with a strong force, they tend to stick to the lid or stick to each other and form lumps, which has a negative effect on the quality of the product.

In order to solve these problems, for example, we have developed a method in which the round frame supporting the raw material case is moved up and down in the oil while it is being flown, and the food raw materials are moved up and down into the oil or placed above the oil surface. A flying method has been proposed that involves repeating the process of putting the object out into the water for several minutes and then letting it stand still in the oil for a while.

However, in the former method, the raw material case is moved up and down while completely immersed in the oil, so it is difficult to ensure that the food, which rises all at once due to large buoyancy, is dispersed and does not stick. This method is extremely difficult, especially when a large amount of food is to be processed, and the latter method requires that the food be removed from the oil during frying. As a result, heating is performed intermittently, which not only reduces heating efficiency and increases frying time, but also has disadvantages such as making it difficult to finish the food fluffy. Hasken)
・There was also the problem that raw materials were frequently damaged inside the factory and products were left unused.

[Problems to be Solved by the Invention] An object of the present invention is to provide a frying method and apparatus that can efficiently fry foods in a short period of time without forming lumps due to mutual sticking. .

[Means for Solving the Problems] In order to solve the problems described above, the frying method of the present invention includes a full immersion state in which a basket containing food is completely immersed in heated oil in a vacuum frying tank. top, y)
The food in the basket is heated for a certain period of time while being moved between a semi-immersed state where the food is exposed to the oil surface and a semi-immersed state where the food is exposed to the oil surface, and then the food in the basket is lifted above the oil to drain the oil. It is something.

The frying device also includes a frying tank for frying the food stored in the bathtub under reduced pressure, a receiving frame for a basket arranged in the frying tank so as to be able to be raised and lowered by an elevating means, and a receiving frame via the cylinder. and a control device for controlling the elevation, and the control device is configured to move the large stent up and down between a fully immersed state in which the entire body is immersed in oil and a semi-immersed state in which two parts are exposed above the oil surface. The four points are that it is configured to control the above-mentioned receiving frame.

[Example] Hereinafter, the present invention will be described in more detail with reference to the drawings.

In FIG. 1, reference numeral 1 indicates a basket with an open top for storing foods to be flown, such as vegetables, fruits, seafood, livestock products, or molded products thereof; A frying tank 3 is a conveyor for supplying the basket 1 into the frying tank 2 and taking it out from the frying tank 2 through an opening 4 which can be freely opened and closed.

The frying tank 2 is always filled with an appropriate amount of oil 8 from an oil tank 6 by an oil supply pump 7, and this oil 8 is heated to a predetermined temperature by a heating pipe 9 using steam as a heat source. Further, a vacuum pump 13 is connected to the upper space of the frying tank 2 through a suction pipe 11 and a condenser 2 for separating water and air, and the vacuum pump 13 can reduce the pressure to a predetermined pressure. . ” Water condensed by cooling in the two-part condenser 12 is transferred to the recovery pipe 1
6 to a collection tank 15 and drain pump 17
losses are sequentially incurred.

In addition, a receiving frame 20 for supporting a two-part squeegee l'l fed through the opening 4 into the frying tank 2,
The lid body 23 which opens and closes the basket 1 supported by the receiving frame 20 is suspended from a support member 22 which is disposed in the piston loft 21a of the cylinder 21 so that it can be raised and lowered freely. By being suspended from the member 22, it can be raised and lowered in synchronization with the receiving frame 20, and the support member 2
It is disposed so as to be able to move toward and away from the basket 1 by means of a second opening/closing mechanism 24. This opening/closing mechanism 24
Any configuration may be used as long as it allows the basket 3 to move toward and away from the basket 1.

The cylinder 21 is connected to a control device 25 including a solenoid valve and a pressure fluid source, and the control device 25 controls whether the basket 1 on the receiving frame 20 is completely immersed in oil or in which only the upper part is above the oil level. It is controlled to move up and down between a semi-immersed state and a state where it is exposed to water.

The two-part basket 1 and the lid 23 are formed of a perforated plate such as a wire mesh or a perforated plate through which oil can flow, and at least the inner surface thereof has heat resistance and oil resistance, and is resistant to food adhesion. It is desirable to coat it with a strong synthetic resin, such as tetrafluoroethylene.

Note that 26 in the figure is an oil drain port for draining the oil 8 in the frying tank 2.

In the fryer having the above configuration, at the start of work, both the receiving frame 20 and the lid 23 are raised to the solid line position in FIG. 1 and are on standby.

In this state, when the basket 1 filled with food is transferred on the conveyor 3, sent into the frying tank 2 through the opening 4, and placed on the receiving frame 20, the opening/closing mechanism 24 is activated to remove the lid. 23 is lowered and the path scaler l-1 is closed.

Next, the opening 4 is closed completely, and the inside of the frying tank 2 is reduced to a predetermined pressure (for example, 5 to 30 Torr) by the vacuum pump 13, and then the cylinder 21 is controlled by the controller 25 according to a predetermined program. , flying is performed while the receiving frame 20 moves downward by -fz.

That is, first, the receiving frame 20, which has been waiting in the raised position shown in FIG. 2A, is lowered to the full immersion position where the basket 1 is completely immersed in oil, as shown in FIG. 2B, and this full immersion is completed. At this position, the food in the basket 1 is heated for a certain period of time. Subsequently, as shown in FIG. 2C, the receiving frame 20 is raised to a semi-immersed position where the upper part of the basket 1 is exposed above the oil surface, and after being heated for a certain period of time in this semi-immersed position, the receiving frame 20 descends again to the above full immersion position, and below,
The food is heated for a predetermined time while the receiving frame 20 repeatedly moves up and down between the full immersion position and the half immersion position.

The number of times and the time interval at which the receiving frame 20 is moved up and down between the full immersion position and the half immersion position can be set as appropriate depending on the type of food to be flown, the amount of filling in the basket, etc. From the start to the end of flying (usually about 10 to 20 minutes), the vertical movement can be set to be performed at equal intervals, or to be performed at stepwise different intervals.

In this way, by heating the food with the basket 1 fully immersed at the start of frying, the entire food is heated evenly, and heating unevenness, which occurs when heating is done with the basket 1 partially immersed at the beginning, can be avoided. It never occurs.

In addition, when heating in a semi-immersed state, a space is formed on the oil surface, so even if foods that have been heated to a certain extent and become easy to stick to the surface float to the surface one after another, they will not be pressed against the lid 23 of the basket 1. Since convection occurs sequentially and the food is automatically stirred, it is possible to reliably prevent these foods from adhering to the lid 23 or from adhering to each other and forming lumps.

Next, when the above-mentioned heating is completed, the receiving frame 20 is moved to the position indicated by the solid line in FIG. The lid 23 is released, the opening 4 is opened, and the basket 1 is taken out. Here, the food may be drained of oil by reducing the pressure inside the frying tank 2 to an even higher vacuum state, or by transferring the basket 1 to a separate room where the pressure can be adjusted. Cooling of food can also be achieved by supplying it with cold air.

The receiving frame 20 can also be configured so that a plurality of baskets 1 can be placed at the same time. In this case, a single large lid body that spans the plurality of baskets 1 is provided, or each / A plurality of independent lids are provided for each socket 1, and these lids are configured to be opened and closed synchronously.

In the above embodiment, the basket 1 is transported into the frying tank 2 by the conveyor 3, but it goes without saying that the basket 1 may be transported manually.

Moreover, although the cylinder 21 is used as a means for raising and lowering the receiving frame 20, other means for raising and lowering, such as a motor, can also be used.

Therefore, when frying food raw materials as described above, since the g ingredients before frying are at a temperature close to room temperature, the oil temperature in the frying tank is adjusted to a temperature higher than the temperature suitable for frying the raw materials. It is desirable to start flying in that state. This is because when flying under reduced pressure as described above, the quality of the product is determined by releasing most of the moisture in the raw materials within a few minutes after the start of the frying and promoting drying of the raw materials as quickly as possible. "Toward"
This is because it is important in achieving the second goal.

Therefore, it is desirable to adjust the oil temperature so that the oil temperature does not drop below the frying temperature suitable for the raw material when low-temperature raw materials are immersed in the oil. FIG. 3 illustrates changes in oil temperature, evaporation, and degree of vacuum during flying.

Furthermore, in order to reduce the residual oil content in the product after frying, it is necessary not only to drain the oil sufficiently, but also to maintain the pressure in the tank as high as possible.

In the present invention, in addition to controlling the oil temperature and degree of vacuum,
By controlling the program such as the time interval of vertical movement of the basket during flying, it becomes possible to manufacture products with a crunchy texture, a porous texture, etc. using all food ingredients.

Next, an experimental example of the present invention will be explained.

(Experiment example■) Core an apple, cut it into quarters, and cut it into 3cm thick pieces using a slicer. Next, it is placed in a soaking tank filled with a low molecular weight sugar solution adjusted to a sugar content of 40 Brix, and after soaking for about 4 to 5 hours, the honey is cut.
Flying treatment was performed under the following conditions.

That is, frying is started at an oil temperature of 120°C in the frying tank, the oil temperature during frying is set to an average of 100°C or less (80 to 95°C), and the pressure condition is a degree of vacuum of 20°C.
I tried to keep it around rr. Then, it was moved up and down between the fully immersed state and the half immersed state at 1.5 minute intervals, and the flying was completed in 12 minutes. After draining the oil in a vacuum, it was taken out from the frying tank and slowly cooled to produce a product.

In addition, as a comparative example, the basket was flown while being moved up and down between the fully immersed state in oil and the fully exposed state in vacuum (Comparative Example 1), and the one in which the basket was kept fully immersed in oil. obtained by flying as is (comparative example 2),
They were compared with products according to the invention. The result is the first
Shown in the table.

As can be seen from the results, the product according to the present invention was completely satisfactory, with no oily content, good color and texture, and almost no breakage.

Table 1 (Experimental Example II >) Slice the capocha into approximately 4 cm square pieces and 2 mm thick.
After performing the same pretreatment as in the experimental example, flying treatment was performed using the same equipment.

Average oil temperature during flying: 95°C 1 Pressure condition: Vacuum 1
f5Torr, flying time 12 minutes, vertical movement was performed at 2 minute intervals 〇 Also, in Comparative Example and 17, Comparative Example 1.2 in Experimental Example ■
A product was obtained under similar conditions and compared with that according to the invention. The results are shown in Table 2.

From this result, it can be seen that the uninvented product has good color and flavor, and has a particularly soft texture.

Table 2 *1 Soft feeling *2 Toughness (experiment example ■) Slice beef into pieces about 5 mm thick, 5 cm wide, and loc cm long, and soak in a sauce mainly composed of soy sauce, spices, sugar, etc. I seasoned it. The taste-treated meat pieces were then subjected to a frying process using the apparatus of Experimental Example (2). At that time, the oil was processed at high oil temperatures to preserve the flavor of the raw materials as much as possible. The conditions at that time were: average oil temperature during flying was 120°C, pressure condition was vacuum degree 20 Tart, flying time was 10 minutes, and vertical movement interval was 1 minute. The results are shown in Table 3.

As you can see, a porous product with good taste was obtained.

Table 3 [Effects of the Invention] As detailed above, according to the present invention, the food is heated while the basket containing the food is moved up and down between the fully immersed state and the partially immersed state. As a result, the entire food can be heated evenly while reliably preventing the food from sticking to the lid or to each other and clumping together. Since there is no lifting, the heating time can be doubled and the heating efficiency can be improved, thereby making it possible to obtain fried foods that are fluffy and have excellent texture. In addition, since the amplitude of the vertical movement of the basket is small, there is little damage to the product, so the yield is high, and it is suitable for mass production and is extremely effective.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway configuration diagram showing an embodiment of a vacuum fryer according to the present invention, Fig. 2 A-C is an explanatory diagram of the frying process, and Fig. 3 shows oil temperature and evaporation during frying. , is a diagram illustrating a state of change in the degree of vacuum. No. 10 basket, 2. - frying tank, 8.. oil,
20. Fist/receiving frame, 21.. Cylinder, 25.. Same device.

Claims (1)

[Claims] 1. A basket containing food is moved up and down in a reduced-pressure frying tank between a fully immersed state in which the entire basket is immersed in heated oil and a semi-immersed state in which the upper part is exposed above the oil surface. A vacuum frying method characterized by heating the food in the basket for a certain period of time while heating the food, and then lifting the basket onto oil to drain the oil. 2. A frying tank for frying the food stored in the basket under reduced pressure, a receiving frame for the basket arranged in the frying tank so as to be able to be raised and lowered by an elevating means, and a control device for controlling the raising and lowering of the receiving frame via the cylinder. The control device is configured to control the receiving frame to move the basket up and down between a fully immersed state in which the entire basket is immersed in oil and a semi-immersed state in which the upper part is exposed above the oil surface. A vacuum frying device characterized by: