JPH0797960B2 - Dried food and manufacturing method thereof - Google Patents

Description

TECHNICAL FIELD The present invention relates to a dry food product and a method for producing the same.

[Prior Art and Problems] For instant foods, dry foods that have been processed into a form that is easy to cook are used. Such dry food is
There are a vacuum freeze drying method and a warm air drying method. By vacuum freeze-drying, a dried food excellent in that the flavor is not impaired and the subsequent cooking is easy can be obtained, but the processing cost is very high and the food structure is impaired. The texture becomes worse.

On the other hand, the hot-air drying method has a very low processing cost compared to the vacuum freeze-drying method and has less tissue damage, but the food obtained by this method has poor hot water reconstitution or reconstitution with water,
It is not suitable for use in instant foods, such as cup ramen, that require hot water reconstitution in a short time.

Therefore, an object of the present invention is to provide a dry food product which does not impair the flavor and texture, is easy to cook, and can be manufactured at low cost, and a manufacturing method thereof.

[Means for Solving the Problems] In order to solve the above problems, the present invention puts a food having a water content adjusted to 10 to 60% on a dry basis into a pressure container, and adds carbon dioxide gas to the pressure container. Introduce carbon dioxide gas pressure 10
Keep the food at more than kg / cm ² and impregnate the food with carbon dioxide gas,
After releasing the pressure of the pressure vessel and subjecting the obtained carbon dioxide gas-impregnated food to rapid heat treatment, further drying with warm air reduces the water content to 10% or less on a dry weight basis. The present invention provides a manufacturing method and a dried food obtained by this method.

The present invention will be described in more detail below.

In the method for producing a dry food according to the present invention, first, a raw material food is put in a pressure vessel. As the raw material food, a commercially available dry food can be used. Examples of such raw material foods include cabbage, leeks, carrots, spinach, spring, parsley, tea leaves, Chinese cabbage, Nozawana, burdock, camphor, radish, kelp, soybean, green peas, rice (polished rice, Brown rice) and other vegetables, cereals, beans, leaf foods and the like. The water content of the raw material food varies depending on the type of dry food before it is put into the pressure vessel, but it is desirable to adjust the water content to 10 to 60% (dry basis, the same applies to water below). This adjustment of the water content can be conveniently carried out by storing the raw material food in the air having a humidity of 60% or more for 10 hours or more, preferably for one day. If necessary, a predetermined amount of water may be sprayed onto the raw material food to adjust the water content, and then the food may be stored for 10 minutes or longer, preferably 30 minutes or longer.

After putting the raw material food whose moisture content is adjusted in the pressure vessel in this way, purge the pressure vessel with carbon dioxide gas or evacuate it, then introduce carbon dioxide gas into the pressure vessel to introduce carbon dioxide gas into the food tissue. Impregnate. In the present invention, the carbon dioxide gas pressure during impregnation is maintained at 10 kg / cm ² or more. The holding time in this pressurized state depends on the carbon dioxide gas pressure, but is 5 minutes or longer, preferably 10 minutes or longer. Needless to say, the temperature during carbon dioxide gas impregnation is the temperature at which carbon dioxide in the pressure vessel maintains a gas state. The pressure vessel used for carbon dioxide gas impregnation is equipped with a carbon dioxide gas introduction pipe, a discharge pipe, a raw material food introduction port and a discharge port, can be sealed and can withstand high pressure, and introduces the introduced carbon dioxide into a gas state. Any device having a temperature adjusting means (for example, a jacket) for holding may be used.

When the carbon dioxide gas impregnation is completed, the pressure in the pressure vessel is released, and the carbon dioxide gas impregnated food is taken out and subjected to rapid heat treatment. The rapid heat treatment can be performed at a temperature of 100 ° C. or higher, preferably about 200 ° C. For example,
Carbon dioxide gas impregnated food is treated for 5 to 6 seconds or less by using an air flow drying device in which a heat medium at the above temperature selected from air, water vapor or a mixed gas thereof is circulated, and a tangential separator or a cyclone separator, etc. The food is separated from the air stream by using and taken out. Alternatively, the rapid heat treatment can also be performed by heating by high frequency dielectric heating. In that case, the heating time is 5 seconds or more in the case of 600 W, depending on the output.

After taking out the carbon dioxide gas-impregnated food from the pressure vessel, it is desirable to subject it to rapid processing within 5 minutes at room temperature and in the shortest possible time. However, at low temperatures, the time can be extended, for example, when cooled to -20 ° C or lower, it can be extended to about 60 minutes.

The presently preferred carbon dioxide impregnation conditions and rapid heating conditions for each food are shown below.

When the water content of the leek is adjusted to 30% or more, the green color fades and the color tone tends to deteriorate even after the treatment. From the viewpoint of the treatment effect and the color tone of the treated product, the water content is most preferably 15 to 25%. The carbon dioxide gas impregnation pressure is preferably 15 kg / cm ² or more. As the rapid heating medium, both heated air and superheated steam can be preferably used, but heated air is preferable from the viewpoint of color tone.

Mainspring Water content is preferably 15-40%, particularly preferably 25-35%
Is. The carbon dioxide gas impregnation pressure is 15 kg / cm ² or more, preferably 25 kg / cm ² or more, more preferably 50 kg / cm ² or more.

From the viewpoint of color tone, the water content of cabbage is preferably 10 to 30%, particularly preferably 15 to 20%. Impregnation pressure is 15 kg / c
m ² or more is preferable. As the rapid heating medium, heated air is preferable from the viewpoint of color tone.

Nozawana Water content is preferably 10-30%, particularly preferably 15-20%
Is. Carbon dioxide gas impregnation pressure is at least 15 kg / cm ²
Is preferred. The rapid heating medium is preferably heated air in terms of color tone.

Chinese cabbage The water content is preferably 10 to 40%, particularly preferably 25% or less. Carbon dioxide gas impregnation pressure is at least 15 kg / cm ²
Is preferred. The rapid heating medium is preferably heated air in terms of color tone.

The water content of burdock is preferably 10 to 40%, particularly preferably 25% or less. Carbon dioxide gas impregnation pressure is at least 15 kg / cm ²
Is preferred. The rapid heating medium is preferably superheated steam from the viewpoint of treatment effect.

Water content of camphor is preferably 10 to 40%, particularly preferably 25% or less. Carbon dioxide gas impregnation pressure is at least 15 kg / cm ²
Is preferred.

Dried radish The preferred water content is 10 to 50%, and the higher the water content within this range, the higher the effect. The carbon dioxide gas impregnation pressure is preferably at least 15 kg / cm ² .

Now, the thus-obtained rapidly heat-treated food is subjected to a hot air drying treatment to reduce the water content to 10% or less. The present inventors have found that, particularly from the viewpoint of hygiene, it is desirable to set the water content of the final dried food to 10% or less. If the water content exceeds 10%, discoloration of food, spoilage,
Awe, etc. are recognized. By the way, if the water content of the food is directly reduced to 10% or less by the rapid heating treatment, the raw material food may be carbonized (burnt) or the original flavor may be impaired by roasting. Therefore, the raw material food subjected to the rapid heating treatment is subjected to a warm air drying treatment at, for example, 40 ° C. to 80 ° C. and dried to a moisture content of 10% or less, preferably to a moisture equivalent to the monomolecular adsorption layer. It should be noted that foods that have been subjected to the rapid heating treatment are 15 to
Often has a moisture content of 35%.

The present invention can be applied to a wide range of foods as shown in the examples described below. However,
For mushrooms such as shiitake mushrooms and mushrooms, the desired purpose cannot be achieved. This is due to the organizational structure of mushrooms. That is, mushrooms form a fruiting body by gathering a single mycelium. The mycelia can be regarded as a single tube, and the carbon dioxide gas impregnated from the inlet of the mycelium vaporizes into the atmosphere as it is due to almost no resistance at the inlet during the pressure release process. In addition, even in the process of rapid heat treatment, carbon dioxide gas is volatilized from the inlet, and an increase in internal pressure due to expansion of the tissue cannot be achieved. In contrast, other foods are generally shaped by independent cell aggregates. Moreover, individual cells are generally surrounded by thick and strong cell walls. There are pores called Desmo tubules in the cell wall, and the size is about 200 to 400 in diameter in the raw state.
Angstrom and big. It is believed that the tubules shrink and close when dried. Therefore, according to the present invention, by adding water before impregnating carbon dioxide gas to adjust the water content, the cell wall swells and flexibility is imparted, and the desmo canaliculi also open and become larger. This makes it possible to achieve expansion by rapid heating after impregnation with carbon dioxide gas.

[Examples] Hereinafter, the present invention will be described more specifically with reference to Examples.

Example 1 500 g of commercially available cabbage flakes cut into flakes and having a moisture content of 6.3% and an apparent density of 1.28 g / cm ³ measured by mercury porosimetry were spread on a wire net and the temperature was 20.0 ° C. and the relative humidity was 80. % Moisture-conditioned air for 48 hours to adjust the water content to 20.0%. Then, the cabbage flakes were put into a cylindrical basket made of wire mesh, and the heat exchange medium was circulated in the outer jacket and charged into a pressure vessel having an internal volume of 4 liters which was maintained at about 17 ° C., and carbon dioxide gas was introduced thereinto to obtain 50 kg. Pressurized to / cm ² . Under this condition, it was held for 20 minutes to impregnate with carbon dioxide gas.

Then, the pressure in the container was released and the carbon dioxide gas-impregnated cabbage flakes were taken out. This was immediately supplied to a gas stream dryer in which a superheated steam flow of 230 ° C. was flowing at 25 m / sec for heating and drying, and after about 2 seconds, the cabbage flakes were separated from the superheated steam flow. This was further dried in warm air at 50 ° C until the water content reached 5.8%.

When the apparent density of the thus obtained cabbage flakes was measured by the mercury penetration method, a value of 0.403 g / cm ³ was obtained, and it was found that the cabbage flakes were swollen about 3.2 times as much as before treatment.

Approximately 100 g of the cabbage flakes after this treatment were poured into boiling water at 90 ° C, and 10 panelists sampled them and observed how they returned to the hot water. After about 1.5 minutes, they became soft and ready to eat. Similar hot water reconstitution states were observed and compared for the raw cabbage flakes (untreated cabbage flakes) not subjected to the treatment of the present invention and the cabbage flakes obtained by vacuum freeze drying. As a result, the untreated cabbage flakes had a slight core even after 3 minutes and had poor crispness. Also, cabbage flakes by vacuum freeze drying became soft and edible in less than about 1.5 minutes, but the color was lost and there was no chewy,
It was inferior to the inventive cabbage flakes.

The cabbage flakes adjusted to have water contents of 14.3% and 27.0%, respectively, had swelling ratios of 1.37 times and 1.78 times, respectively. Thought to be.

Example 2 Under the conditions shown in Table 1 below, the raw cabbage flakes or chips having the water content shown in the same table were impregnated with carbon dioxide gas, subjected to rapid heat treatment and warm air drying, and the water content of the obtained dried cabbage flakes was obtained. Swelling rate and state of hot water reconstitution (each placed in a wire mesh basket with a stainless steel lid and soaked in boiling water at 97 ° C for 3 minutes, sampled by 15 people, with a coreless and good texture, A, slightly cored Was evaluated as B, that having a core remaining poorly crimped was C, and that having a core remaining difficult to bite was D). The results are shown in the table. The expansion rate is the quotient of the density of the raw cabbage obtained by the mercury injection method and the density of the processed cabbage obtained by the mercury injection method.

Test Example A With respect to the dried cabbage flakes obtained in No. 9 of Example 1 and Example 2, the viable cell count was measured by the dilution plate method. The results are shown in Table A below. The results of untreated raw cabbage flakes are also shown.

From these results, it can be seen that the dried cabbage flakes obtained in No. 9 of Example 1 and Example 2 are sufficiently sterilized and are very hygienic.

Test Example B Commercially available instant yakisoba oysters (containing about 5.5 g of hot air dried cabbage flakes) were taken out, and 6 g each of the No. 8 inventive cabbage flakes, hot air dried cabbage flakes and vacuum freeze dried cabbage flakes were placed in hot water. Pour, cover and store for 3 minutes. After storage, they were drained, sprinkled with sauce, mixed well and sampled. The vacuum freeze-dried cabbage had a significant absorption of the sauce and could not withstand food. In addition, the hot air dried cabbage had insufficient restorability, and there was a part where the core remained, and the texture was bad. On the other hand, the cabbage of the present invention had good restorability, was well compatible with the sauce, and had an excellent texture.

Example 3 Cut into slices, moisture content 3.9%, apparent density 0.782 g /
Put 500 g of commercial green onion chips dried in warm air to cm ³ into a ball-shaped rotating container, rotate it about 30 times per minute while spraying water in a mist to moisten the specified amount, then put it in a sealed vinyl bag for 2 hours. I kept it. The water content after storage was 17.8.
%Met. Next, the spring onion chips were placed in a pressure vessel having an internal volume of 4 liters, which was kept at about -9 ° C by circulating a heat exchange medium in the outer jacket, sealed, and then deaerated by a vacuum pump for about 20 seconds. After that, carbon dioxide gas was introduced into the pressure vessel and the pressure was increased to 25 kg / cm ² . While supplying carbon dioxide gas on the way, this state was maintained for 20 minutes to impregnate carbon dioxide gas.

Then, the pressure in the container was released, and the leek chips impregnated with carbon dioxide gas were taken out. Approximately 100 g of this is immediately 160 ℃
The superheated steam flow was heated at 25 m / sec and was heated and dried, and after about 5 seconds, it was separated from the superheated steam flow and the green onion chips were taken out. This was further dried for 6 minutes in warm air of 50 ° C. (flow rate 0.5 m / sec) to make the water content 5.5%.

When the apparent density of the green onion chips thus obtained was measured by the mercury porosimetry, a value of 0.283 g / cm ³ was obtained, and it was found that the swelling was about 2.76 times that before the treatment.

On the other hand, about the remaining green onion chips impregnated with carbon dioxide gas
Spread 400 g in a freezer kept at -30 ° C and store,
After 100 minutes, about 100 g, about 20 minutes, about 100 g, and about 30 minutes, about 100 g were similarly subjected to the rapid heating treatment and the warm air drying treatment.
Swelling rates after treatment are 2.83, 2.65, and 2.78, respectively.
It was twice, and there was almost no change. When the hot water reconstitution test in Example 2 was carried out, the recoverability was superior to that of the untreated spring onion chips and was almost the same as that obtained by freeze-vacuum drying.

Example 4 Under the conditions shown in Table 2 below, carbon dioxide gas impregnation, rapid heat treatment and warm air drying were performed on raw material green onion chips having the water content shown in the same table, and the water content, swelling ratio and The state of reconstitution with hot water was measured. The results are shown in the table.

Example 5 Under the conditions shown in Tables 3 to 12 below, carbon dioxide gas impregnation, rapid heat treatment and warm air drying were carried out on various raw material foods having the water content shown in the same table, and the water content of the obtained dry food, The expansion rate and the state of reconstitution with hot water were measured. The results are shown in the table.

Test Example C Approximately 20 g of the dry spring of No. 4 in Table 5 was reconstituted in boiling water at 90 ° C for 5 minutes (returning time for general cooking is said to be 4 days in water), followed by washing with water After draining, bonito soup (cup 1), sugar (1 tbsp), soy sauce (2 tbsp) were added, cooked, tasted by 10 panelists, and the water return, flavor and absent condition were observed. The untreated mainspring was also returned to hot water and cooked in the same manner, and the respective states were observed and compared. As a result, the mainspring of the present invention was soft, had a good flavor and chewy texture, had less acridness, and had good scum removal. On the other hand, the untreated spring was atrophied in appearance, had insufficient reconstitution with hot water, was hard and had a bad chewy texture, and had a strong acclimation, and was insufficient in removing the slag.

Test Example D Approximately 100 g of dried soybean No. 4 in Table 10 was rehydrated in boiling water for 20 minutes, drained, cooked with bonito soup, sugar and soy sauce, and then cooked by 10 panelists. Was observed. The untreated soybeans were also returned to the hot water and cooked in the same manner to observe and compare the states of the soybeans.
As a result, the soybean of the present invention had good chewy texture, good reconstitution in hot water, and rich soybean-like flavor and umami. On the other hand, untreated soybean was insufficient in reconstitution with hot water, was hard, and could not be eaten.

Example 6 Carrot chips subjected to water content adjustment and carbon dioxide gas impregnation under the same conditions as in Example 1 were taken out of the pressure vessel and immediately put into an airflow dryer in which a heated air stream at 220 ° C flowed at 25 m / sec. After being supplied and subjected to rapid heat treatment, they were separated from the heated air stream and taken out after 1 second and 2 seconds, respectively. Moisture content of rapid heating time of 1 second is 29.8% to 14.5%
The water content of the rapid heating time of 2 seconds is 29.8%
It had decreased to 8.5%. The one with a rapid heating time of 2 seconds showed dark browning due to rapid drying and the color tone was poor as compared with the one with 1 second.

The one with a rapid heating time of 1 second was dried with warm air at 50 ° C. for about 30 minutes to adjust the water content to 6.5%. The color tone was good and no effect of hot air drying was observed. In addition, when the rapid heating time of 1 second was dried with warm air at 50 ° C and not dried for 1 week, each was left in a harmony room at 20 ° C and 65% relative humidity for observation of appearance changes. No change was observed in the appearance of the product dried with warm air.
On the other hand, discoloration, rot, and atrophy due to the growth of microorganisms were observed in those that were not dried with warm air.

[Effects of the Invention] As described above, according to the present invention, the restoration property is superior to that obtained only by hot air drying, the restoration property is almost the same as that obtained by vacuum freeze drying, and further, the one obtained by vacuum freeze drying is used. Is more natural than tissue has no texture, and is sterilized by performing rapid heat treatment at high temperature, and further dried with warm air to give a low water content that is not suitable for the growth of bacteria. It is possible to obtain a dry food product having a low amount of waste and having good storage stability at a relatively low cost. The dry food of the present invention can be widely used as an instant food such as instant noodles and instant miso soup, as well as a processed food material and a cooking material.

Continuation of the front page (72) Inventor Kensuke Uchiyama 1-31 Kurobeoka, Hiratsuka-shi, Kanagawa Examiner Koichi Niimi, Institute of Industrial Science, Japan Tobacco Inc.

Claims (2)

[Claims] 1. A food having a water content adjusted to 10 to 60% on a dry weight basis is placed in a pressure vessel, carbon dioxide gas is introduced into the pressure vessel, and the carbon dioxide gas pressure is kept at 10 kg / cm ² or more to produce food. After impregnating carbon dioxide gas, releasing the pressure in the pressure vessel, and subjecting the obtained carbon dioxide gas-impregnated food to rapid heat treatment, further dry with warm air to reduce the water content to 10% or less on a dry basis. A method for producing a dry food, characterized by: 2. A dried food product obtained by the method according to claim 1.