JPH0789855B2 - Vegetable Chips Manufacturing Method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing dry carrot and burdock chips having a fresh flavor and an appropriately swollen crispy texture.

(Prior Art and Problems Thereof) A large number of snack foods have been developed, and accordingly, various kinds of research and development have been conducted on the drying technique. Typical examples include hot-air drying method, microwave drying method, freeze-drying method, frying method, and vacuum drying method. Further, the material to be dried is heated and dehydrated by exposing it to a stream of superheated steam for a short time. There is a swelling drying method in which a product is rapidly released into the atmosphere to obtain a swelled product. However, the snack food obtained by such a conventional drying method has a drawback that a heating odor is generated due to heat during drying, or the flavor of the food is volatilized / altered.

The applicant of the present invention, as a method for producing snack foods in which such drawbacks are resolved, is a group consisting of vegetables, fruits, cereals, beans, solids such as dough formed mainly of cereals, or solids obtained by processing and cooking these solids. The one or more kinds of foods selected from the above are placed at a speed sufficient for the foods to swell and under a rapid depressurization condition such that the water in the foods freezes, and the waters in the foods freeze. A method for producing a snack food, which is characterized by post-heating and drying, and then returning to normal pressure, was developed and filed previously (Japanese Patent Application No. 58-34925).

However, when carrots and burdock are treated by the above-mentioned snack food manufacturing method, it is not always sufficiently satisfactory in that a stable quality product that is always dry and lean is obtained.

(Means for Solving the Problem) The present invention intends to solve the above problems and provide a novel drying method for obtaining chips having a crispy texture and appearance preferable as a snack food.
The gist is that carrot or burdock that has been cut into an appropriate size beforehand. Hot water treatment ,. Freezing and thawing ,. Heat treatment in syrup as appropriate ,. Place under rapid depressurization at a rate sufficient to cause swelling ,. Further, heat-drying with the reduced pressure reduced ,. It is a method for producing vegetable chips, which comprises returning to normal pressure and sequentially carrying out the above steps.

The details of the present invention will be described below.

The target vegetables of the present invention are carrots and burdock. These carrots and burdock are cut into appropriate sizes beforehand. The size at the time of cutting is not particularly limited, but it is preferably cut into slices having a thickness of 3 to 5 mm in consideration of eating as a snack. Next, the cut carrot or the like is treated with hot water to enhance water absorption in the carrot or the like and soften the tissue. Therefore, the conditions of the hot water treatment are not particularly limited as long as these objects can be achieved, and specifically, about 70 to 100 ° C. for about 10 to 20 minutes is sufficient. Then, the carrot and the like are frozen and then thawed. As a result, the entire tissue such as the carrot is sufficiently softened. The freezing method and freezing conditions are not particularly limited, but the frozen carrot is generally frozen at -10 ° C or lower, and the thawing method and the thawing conditions include hot water immersion, hot air treatment, microwave treatment, infrared treatment, etc. Continue until it is almost completely thawed.

The carrot or the like treated as described above is then heat-treated in a syrup to allow a suitable amount of sugar to penetrate into the carrot or the like. In this case, since carrots and the like have their tissues sufficiently softened by hot water treatment and freeze-thaw treatment, the sugar content is relatively quickly permeated by the heat treatment in the syrup. The heat treatment in this syrup is useful for permeating a suitable amount of sugar into carrots and the like, and making the texture of the finally obtained chips crispy. Therefore, it is possible to freely adjust from a crispy texture with a hard texture to a crispy texture with a soft texture by adjusting the amount of the sugar to be permeated. The sugar concentration of the syrup used is preferably about 8 to 20 in Brix degree, more preferably about 10 to 18 in Brix degree. When the Brix degree becomes 8 or less, a sufficient amount of sugar does not permeate, and as a result, it becomes difficult to obtain a crispy texture, and the time required for permeation of sugar is sufficient to sufficiently permeate sugar. Is getting longer. On the other hand, when the Brix degree becomes 20 or more, the sugar penetrates too much and becomes too hard in texture, and it becomes difficult to adjust the amount of penetration of sugar, resulting in a uniform texture. Things are hard to come by.

The carrot or the like treated in this way is then subjected to vacuum expansion treatment. In this case, it is necessary to carry out rapid depressurization at a speed sufficient for expansion. When the food is placed under reduced pressure, the boiling point of water is lowered, thereby causing the evaporation of water in the food, especially free water, but the food is swollen by the evaporation occurring in a short time and rapidly. . From this, the speed sufficient for swelling in the present invention means a speed sufficient for rapidly evaporating water in carrot or the like in a short time. The swelling phenomenon due to water evaporation differs depending on the type of food, and therefore the rate at which swelling occurs is also different depending on the type of food, but it is preferably within 1 minute.

Under the above conditions, the degree of reduced pressure is preferably 150 to 500 Pascal. When the degree of reduced pressure is 150 pascals or less, the chips have a soft texture lacking crispy, and when the degree of reduced pressure exceeds 500 pascals, the chips have a dried and very hard texture.

The time for placing carrots or the like under the above-mentioned conditions is preferably about 5 to 15 minutes, whereby a suitable frozen state is maintained while maintaining the shape.

After that, a heat drying treatment is performed in a state where the degree of reduced pressure is further reduced. The reason why the degree of reduced pressure is further lowered during the drying by heating is to dry without heating and maintaining appropriate internal freezing, and specifically, it is preferably lowered to 30 to 50 pascals. The heat drying condition is 60 to 90 ° C. until the water content of the final product is 5% by weight or less.
When the drying temperature becomes 60 ° C. or lower, the drying time becomes longer and the chips have a soft texture and lack crispness. On the other hand, when the heating temperature exceeds 90 ° C., the flavor of carrots and the like is impaired and dried chips are obtained which have a very hard texture. The heating means is not particularly limited, but radiant heating such as infrared rays is most preferable. Next, the carrot and the like obtained by heating and drying are returned to normal pressure and then transferred to the next step such as the packaging step.

Next, a concrete apparatus that can be used for carrying out the method of the present invention will be described with reference to FIG.

Reference numeral 1 denotes a drying chamber, and lids 2, 3 are provided on the upper and lower portions of the drying chamber 1.
Is provided, and a shelf 4 for placing the material A to be dried is provided therein. The shelf 4 can be inverted by a handle 5. An infrared lamp 6 is installed inside the lid 2 of the drying chamber 1. A vacuum chamber 7 is connected to the side wall of the drying chamber 1 by a pipe 8.
A valve 9 for opening and closing the pipe 8 is installed. A cold trap 10 and a vacuum pump 11 are connected to the vacuum chamber 7 by a pipe 12 in order to reduce the pressure inside the vacuum chamber 7, and a vacuum gauge 13 is installed in the vacuum chamber 7.
Is provided. The drying chamber 1 is provided on one side wall of the drying chamber 1.
A vacuum gauge 14 for measuring the degree of pressure reduction inside is provided, and apart from this, an air supply pipe 15 is connected,
The air supply pipe 15 is provided with a valve 16 for opening and closing it.

(Effects) According to the method of the present invention, it is possible to obtain chips which retain the fresh flavor originally possessed by carrots and burdock and which are dry and have an excellent appearance. Further, since the chips are appropriately expanded and have a crispy texture, they are extremely excellent as snack foods.

(Example) Example 1 Carrots were sliced into 4 to 6 mm thickness, and then about 10 in boiling water.
Heat treatment was performed for a minute. Then, it was frozen at −10 ° C. or lower, immersed in hot water for thawing treatment, and heat-treated in a sucrose solution having a Brix degree of 15 for about 15 minutes. The carrot thus obtained is placed on the shelf 4 in the drying chamber 1 and the lid 2 is closed. Separately from this, vacuum pump 11 with valve 9 closed
Is operated to bring the inside of the vacuum chamber 7 to 30 Pascal.
After the above operation was completed, the inside of the drying chamber 1 was depressurized to 300 Pascal for a short time (within 1 second) by opening the valve 9 with the valve 16 closed. Immediately thereafter, the valve 9 is closed and the pressure in the vacuum chamber 11 is reduced to 20 Pascal. In the meantime, the pressure reduction degree in the drying chamber 1 is kept at 300 Pascal for about 5 minutes, and then the valve 9 is opened again to reduce the pressure reduction degree in the drying chamber 1 to 30 Pascals, and the infrared lamp 6
Then, it was dried at a temperature of 80 ° C for 4.5 hours. After that, the valve 9 is closed, the vacuum pump 11 is stopped, and the valve 16
Was gradually opened to return the inside of the drying chamber 1 to a normal pressure, the lid 3 was opened, the handle 5 was rotated to invert the shelf 4, and dried carrot chips were obtained. The water content of the carrot chips was 2.5% by weight.

Comparative Example Carrots were sliced into 4 to 6 mm thick pieces, and then subjected to rapid vacuum expansion treatment and drying treatment under the same conditions as in Example 1 to obtain carrot chips.

The carrot chips obtained in Example 1 and Comparative Example were compared in flavor, appearance and texture. As a result, with respect to flavor and appearance, the product of Example 1 had a fresh flavor and had an extremely preferable appearance with no dryness. On the other hand, the product of Comparative Example is not so different in flavor from the product of Example 1 to the left, but the outer layer portion was not dry and did not retain the appearance before drying. On the other hand, regarding the texture, the product of Example 1 had a crispy texture with a crunchy texture, whereas the comparative product had a different texture between the outer layer portion and the inner layer portion, and also the overall crispy texture. The texture was lacking.

Example 2 Burdock was sliced into 4 to 6 mm thick pieces, and then heat-treated in boiling water for about 10 minutes. Then, it was frozen at −10 ° C., immersed in hot water for thawing, and heat-treated in a sucrose solution having a Brix degree of 10 for about 20 minutes. Put the burdock thus obtained in the drying chamber 1 and depressurize it to 500 Pascal, then keep it in that state for about 15 minutes, then reduce the depressurization degree to 50 Pascal and dry at 60 ° C for 7 hours. The burdock chips having a water content of about 3% by weight were obtained by performing rapid depressurization and drying in the same manner as in Example 1 except for the above.
The burdock chips thus obtained had a fresh flavor and a favorable dry appearance, and were favorable as a snack having a crispy texture.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of a specific apparatus that can be used in carrying out the present invention. 1 ... Drying chamber, 2, 3 ... Lid, 4 ... Shelf, 5 ... Handle, 6 ... Infrared lamp, 7 ... Vacuum chamber, 8, 12 ... Pipe, 9, 16
… Valve, 10… Cold trap, 11… Vacuum pump, 1
3,14 ... Vacuum gauge, 15 ... Air supply pipe

Claims (4)

[Claims] 1. A carrot or burdock that has been cut into an appropriate size in advance, Hot water treatment ,. Freezing and thawing ,. Heat treatment in syrup as appropriate ,. Place under rapid depressurization at a rate sufficient to swell. Further, heat-drying with the reduced pressure reduced ,. A method for producing vegetable chips, which comprises returning to normal pressure and sequentially performing the above steps. 2. The method for producing vegetable chips according to claim 1, wherein the syrup has a Brix degree of 8 to 20. 3. The method for producing vegetable chips according to claim 1, wherein the rapid depressurization condition is 150 to 500 Pascal within about 1 minute, and then the temperature is maintained for 5 to 15 minutes. 4. The conditions for heating and drying are 30 to 50 Pascal, 60 to
The method for producing vegetable chips according to claim 1, wherein the final product is dried at 90 ° C until the water content of the final product is 5% by weight or less.