JPH0151994B2 - - Google Patents

Description

[Detailed description of the invention]

By actively utilizing the dehydrating power of silica gel with a large pore volume, the present invention can efficiently and appropriately dehydrate water-rich agricultural, aquatic and livestock products at room temperature or low temperature without deteriorating their quality, and in an energy-saving manner. The aim is to improve quality, storage stability and distribution. Conventionally, when it comes to foods, feeds, fertilizers, and other natural products, as well as processed foods, substances with a high moisture content deteriorate and rot very quickly, and various measures have been taken to prevent this, including dry freezing. However, either method requires a considerable amount of equipment and energy. Although silica gel has conventionally been widely used as a moisture-proofing agent, such as seaweed and seaweed, to prevent moisture absorption, it has never been actively used for processing or dehydration as in the present invention. The structure of the present invention is constructed according to the synergistic effect of using silica gel with a large pore diameter and a synthetic resin with high water absorption. First, polyvinyl alcohol resin film (hereinafter referred to as poval film), which is typified by water-absorbing synthetic resin film,
The moisture permeability of water depends on the relative humidity and temperature of the atmosphere, but in the case of saturated water vapor, it is about 100 g to 400 g/day, ^m2 , which is not much different from the amount of evaporation of water in a static state. It can contain up to 50% water, and when it is dehydrated from the back side of the film by a desiccant such as silica gel, the rate of moisture permeation is amplified, depending on the degree of adhesion of the wet material. The amount of moisture permeability reaches several times as much as 1 to 2/day/ ^m2, almost regardless of the thickness. On the other hand, the silica gel used in the present invention has an average pore diameter of 70 Å to 140 Å (B type, ID
type), which is several times larger than the conventionally widely used type A (22 Å). The reason for this is, as shown in the table below, that not only does it have a large pore capacity and only a small amount is needed, but it also has excellent moisture adsorption ability especially under high humidity, and it is extremely easy to dehydrate and regenerate by heating. It has the advantage of being energy-saving and can be used any number of times, and it does not over-dehydrate the treated material and has the effect of improving the quality of the water-rich natural raw material without impairing it. Type A silica gel has too strong a dehydrating power and only the surface of the treated material dries quickly, which impedes subsequent dehydration and not only fails to achieve its purpose, but also requires high regeneration temperatures, making it impractical.

[Table] On the other hand, various water-rich agricultural, fishery, and livestock products (hereinafter referred to as processing targets), especially those that are highly harvested, are difficult to dispose of. Due to its high moisture content, it will rot, ferment, and deteriorate within 20 to 40 hours, so treatment to reduce its water activity or sterilization is required, which temporarily requires a large amount of equipment and energy, making it difficult to save energy. The only option is to let it dry naturally. However, in static natural drying as mentioned above, the amount of water evaporated from the surface is
Since the water content is only 100 to 400 g/day・m ² , bacterial growth increases until the water activity drops to such an extent that bacterial growth is not allowed, and it has traditionally been difficult for the treated material to escape from this deterioration. It was hot. According to the present invention, all of the above problems can be solved. For example, to dry 1 ton of sardines, even if the fish bodies are 1 cm thick and lined up tightly, more than ¹⁰⁰ m2 of land space is required.
It goes without saying that in rainy weather, but if it's cloudy and windless, everything will rot. The reason why the utilization rate of sardine, the most caught fish, is only 8% even today is mainly due to the above reasons.
According to the method of the present invention, it is easy to achieve the amount of dehydration required to reduce the water activity to 0.9 or less, preferably 0.8 or less at a rate of 1 to ² days per m2 within 20 to 40 hours, and the required amount The space is only a few tenths of the size. That is, first, on a 1 m ² board,
Spread ID type silica gel or a mixture thereof to a thickness of 1 cm, and then spread POVAL film on top of it.
Arrange the sardines on top of this film, then cover with Poval film, then spread silica gel to a thickness of 1 cm, and stack Poval, sardine, Poval, gel, etc. in multiple layers. The object to be treated (sardines) located between the poval films rapidly absorbs water from the contact surface and is dehydrated to reach an equilibrium with relative humidity between the films of 60% or less. The relationship between the water absorption amount of each type and the equilibrium water activity value is shown in the table below.Sardine is dehydrated through the film until it shows an equilibrium water activity value with the water activity value of silica gel, so type B silica gel

[Table] The yield of sardines is 40% (moisture 50%; water activity 0.7),
ID gel has a yield of 60% (67% water; water activity 0.8)
It will be dehydrated indefinitely with the goal of water activity
If it is less than 0.9, it has a very good shelf life, so it can be removed and packaged separately, and the silica gel can be reused. Although the number of layers is not infinite, if you stack 20 layers, the land space required will be 1/20th. Moreover, dehydration can be achieved reliably and precisely regardless of rain or shine, and high-quality fresh and dried fish of desired quality can be obtained. You can of course use any moisture-permeable material such as cloth, paper, or maltoprene between the poval film and silica gel to adjust the degree of dryness, or pre-treat the fish by removing internal organs, draining blood, salting, seasoning, cutting, etc. . After dehydration, the film may be attached to the product or removed and reused.
Adding it to the product is more effective in preventing secondary contamination and has a good shelf life. Furthermore, in carrying out the present invention, the object to be treated may be individually packaged with a poval film, or the silica gel may be wrapped separately in cloth or the like for convenience. Dehydrate. By doing this, fresh dried fish with so-called intermediate moisture content can be produced at low temperatures, and unlike paper or cloth, poval film does not permeate bacteria and has little oxygen penetration, making it delicious and long-lasting. Silica gel can be dried by sunlight, ventilation, or any other suitable method. The method of the present invention can improve the production method and quality of not only fish but also other marine products, such as high-moisture and difficult-to-dry products such as tokoroten and jellyfish. The effect of the method of the present invention on fresh shiitake mushrooms is the same as above, but in this case, rather than obtaining completely dried shiitake mushrooms, the effect of the method of the present invention on fresh shiitake mushrooms is to improve the shelf life of fresh shiitake mushrooms that have been packaged or stored in a warehouse. , there is greater value in streamlining shipping adjustments. This is because poval film and fresh shiitake mushrooms have poor adhesion, and dehydration is slow. However, fresh shiitake mushrooms that are automatically packaged in poval film bags with excellent thermal adhesion can be stored in piles in moderate humidity without swelling and rotting due to the silica gel having large pore diameters. , gradually dehydrated. ID type gel is suitable and can be applied to store many vegetables other than shiitake mushrooms. For meat, even more sophisticated dehydration processing is possible. Transparent raw ham, which is considered to be the highest quality product, is difficult to produce using conventional methods, and it was considered impossible to produce it unless it was gradually dried in a hygienic environment with a completely controlled dehydration rate. According to the authors, dehydration at a low temperature of around 4°C is rather effective, and allows for delicate dehydration without any secondary contamination that can be achieved inside the film, avoiding the formation of hardened surface rings. By wrapping the raw meat in Poval film, it is possible to easily produce transparent, high-quality intermediate moisture dried meat (raw ham). Liquid smoke is used during pre-treatment salting. The effects of the present invention are also remarkable in processed foods, such as noodles. Dry noodle production is a good alternative preservation method due to hydrogen peroxide regulations, but over-drying deteriorates the quality of the noodles, so the regulated production of semi-dry noodles has been proposed. However, with the conventional air drying method,
Although it is necessary to dry with sterile air and the cost of the equipment is large, it is obvious that the method of the present invention can easily produce products whose dryness is controlled aseptically. Although it is not a food product, the method of the present invention is also extremely effective for dehydrating chicken manure. Silica gel has the ability to adsorb foul-smelling gases, and storing chicken manure in Poval bags and dehydrating it from the outside is efficient.It does not cause any foul-smelling pollution and can be handled hygienically in a small space. It has the advantage of being able to be shipped. Some examples will be presented below. Example 1 Five frozen sockeye salmon were cut into three pieces to obtain 10 pieces of thawed fish. Mix 200g of ultrafine salt particles and 50g of liquid smoke to make a paste, apply 25g of this to one side of each fish, wrap each piece individually in a 30cm x 50cm piece of Poval film 40μ thick, and place this on newspaper. Arrange. B-type silica gel is spread under the newspaper, the packaged fish body is covered with the newspaper, B-type silica gel is spread on the newspaper, and several layers are placed in the Toro box as described above. The weight of the original section is 930g ~ 700g
Separately, 800 g of bare sections and POVAL film-wrapped sections were left at room temperature as subjects. The average room temperature is
The samples were taken out after 3 days at 15°C and various studies were conducted as follows. First of all, the initial total weight of the fish decreased from 750g to 550g, and the individual comparison showed that the water activity was 81.2% ± 1.5%.
The product was 0.9 with little variation, beautiful and delicious, and had extremely high commercial value. When sliced, it is the highest quality sliced salmon of its kind. Regarding storage stability, there are large differences depending on various conditions. If it is stored in a polyethylene film and kept chilled, there will be almost no change in taste, color, or flavor even one month after production. When sliced and stored in vinylidene chloride film, the sliced portion
Neto colonies were observed to develop after about 6 days at room temperature, but those kept under chilled conditions showed no signs of this even after 3 weeks. When cut into 2 to 2.2 cm pieces, packaged individually, and dehydrated, the product reached 73% after 3 days (72 hours), and the shelf life of this product was even better, with no change at all after one month at room temperature. On the other hand, the target product already gave off a strange odor after 20 hours and had completely spoiled by the day the dehydrated salmon of the present invention was finished. That is, during the implementation of the method of the present invention, no bacterial growth is observed even at room temperature. This example increases the added value of frozen raw salmon after thawing, but if implemented at the production site, it can save energy for freezing and thawing, and also eliminates the sour odor of raw salmon, which is extremely effective. You can easily produce high-quality products. Example 2 Fresh shiitake mushrooms are best stored in an atmosphere with a relative humidity of around 75%, and the water absorption curve of ID gel reaches an inflection point around this point. To store fresh shiitake mushrooms, pack them individually in 100-200g bags (average 20g per mushroom) by sealing them in poval film bags. Separately, a quilted moisture absorbing sheet with a core made of a laminated P/P long fiber and ID type silica gel is prepared, and the poval film-bagged shiitake mushrooms are arranged on this sheet and stacked in a warehouse. After 130 hours, the raw shiitake mushrooms that were simply bagged became soft, but the dehydrated shiitake mushrooms of the present invention had no problems even after 200 hours. However, if stored for a long time, the weight of the shiitake mushrooms will drop to less than one-fifth of their original weight and turn into dry shiitake mushrooms, so remove the moisture-absorbing sheet at an appropriate time and use the mushrooms until the moisture is saturated. Once done, the sheets can be recycled in a futon dryer, etc. If you apply the same method to bananas, leafy vegetables, etc., you will lose some weight, but the flavor and preservability will improve.
It can be stored in a small place. Example 3 POVAL film is unrolled from a roll, and fresh seaweed is spread as thinly as possible on top of it. POVAL film is unrolled from another roll so as to sandwich the raw wakame, and when these three layers are wound up. , silica gel type B is rolled up as an additional layer. Once the roll is a suitable size, cut it and store it. After 50 hours, if the same amount of silica gel B is used as raw wakame, the wakame will be rapidly dehydrated to less than one-fifth of its weight, and as a result, it will retain its extremely bright color and fresh flavor. If silica gel is not used, wakame will lose its color in 1-2 days and begin to rot in 2-3 days. No other dehydration method has been found that can perform dehydration at low temperatures, as efficiently as this, and in a small space. Similar methods can be applied to other seaweeds and medicinal herbs. Once the object to be treated has been dehydrated, the roll is rewound and the silica gel is collected, dried and reused. The temperature of the dryer is preferably 60°C to 120°C, and the product is used after being cooled after regeneration. Example 4 Drying data regarding open-drying of urume sardine using the same method is as shown in the table below.

[Table] Depending on the purpose, fish may be dehydrated for about 5 hours and distributed as fresh fish, dehydrated for more than 10 hours and shipped as a high-quality raw-dried product, or completely salt-dried. Of course, the dehydration efficiency varies depending on the species of fish, the size of the fish, the pretreatment method, etc., but it is not affected by weather conditions such as temperature and humidity, and it produces a product that is superior to the cold air drying method. As mentioned above, in the method of dehydrating agricultural, aquatic and livestock products of the present invention, the synergistic effect of the poval film, which has high water absorption, and the silica gel, which has a large pore diameter, allows the high-moisture object to be treated at a low temperature. It has the advantage of being able to achieve sophisticated dehydration while suppressing oxygen infiltration.It is extremely productive, hygienic, and energy-saving, and can be used in a wide range of applications.The clean product quality is excellent, high-quality, and has a long shelf life. It has many advantages, such as superior performance.

Claims (1)

[Claims] 1. Raw shiitake mushrooms, vegetables, chicken manure, fresh seafood, seaweed, meat,
In addition, when processing various water-rich agricultural, aquatic and livestock products such as various processed foods, water is adsorbed on silica gel with a large average pore diameter through a water-absorbing synthetic film such as POVAL film (polyvinyl alcohol resin film). A method for dehydrating agricultural, aquatic and livestock products, characterized in that the silica gel is dried and reused.