JPS6232898B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a new method for processing fresh seafood that maintains its freshness, rapidly dehydrates it, is hygienic, has a long shelf life, and is energy saving. To increase the added value of fresh seafood, increase its distribution, and achieve energy saving for distribution. Fresh seafood is rich in moisture, and the rate of spoilage and spoilage is not comparable to land-produced meat. Refrigerated (chilled)
However, it cannot be kept for more than 3 days, so the preservation method has been salting, drying,
We have seen advances in freezing, the use of preservatives, etc., but it is difficult to control these techniques due to taste and storage stability.
There are advantages and disadvantages to the effects. Since the method of the present invention is relatively simple in technique, easy to control, and energy-saving, it is a very promising treatment method, and its outline will be explained below. First, the moisture content of fresh seafood is approximately 75%, and some exceed 80%, but the water activity of most of them exceeds 0.99. On the other hand, the growth of common bacteria is inhibited at a water activity of 0.90 or less, and wild yeast
0.85, and molds are inhibited at 0.80 or less, so conventional preservation treatments, including salting, drying, and cooling, do not require the use of antibacterial agents.
This is the only way to reduce the water activity.
However, in relation to taste, for example, if it is too dry, it will taste bad, and if you try to make it taste better, it will not keep well. As a result of various studies, the present inventor has completed this technique using an appropriate combination of cellophane and silica gel. Cellophane is related to humidity
At around 60%, the water permeability is not very large,
At 90% or more, it is a semi-permeable film with extremely high moisture permeability, and has various interesting properties such as allowing salt to pass through but not organic matter or oxygen. On the other hand, the silica gel used in the present invention, a conventional general-purpose desiccant with a specific gravity of about 0.75 (hereinafter referred to as A-type silica gel), has too strong water absorption power and a small pore volume, so its water absorption capacity is The water is also small, and only the surface of the fish is strongly dried and solidified, inhibiting the progress of dehydration inside the fish body.
In order to carry out drying, the silica gel must be replaced intermittently several times, which is difficult to control and requires much labor and cost, making it impossible to carry out. When drying seafood, not only this method but also wind tunnel drying methods, for example, the quality of the finished product may be seriously affected depending on how well the air volume, temperature, humidity, etc. are controlled in the wind tunnel. As is well known, in the method of the present invention, the problem can be solved by using silica gel with large pore diameter and pore volume (hereinafter referred to as B-type silica gel) and cellophane. It is something that The type B silica gel used in the method of the present invention has an apparent specific gravity of 0.5 to 0.36, a pore volume of 0.80 to 1.10, and an average pore diameter of 70 Å to 120 Å, all of which are twice as large as those of type A. In other words, type A silica gel works in an atmosphere with relatively low humidity, whereas type B silica gel works in an atmosphere with relative humidity of 60% or more and at low temperatures, as shown in Tables 1 and 2. It acts strongly, and its water absorption amount reaches over 60% of its own weight.

【table】

[Table] In addition, when cellophane is used, the drying process does not become too strong, so only the surface of the fish and shellfish is not hardened and dried too much, and the water absorption rate related to the relative humidity is also constant. It has been found that by predetermining the ratio of dryness and silica gel, the water activity can be smoothly reduced to a predetermined level while controlling the desired dryness level. Furthermore, when recycling used B-type silica gel,
There is no need for high temperatures of 180°C to 200°C as required for mold regeneration, and dehydration can be easily performed by sun drying, air drying, etc., which is extremely important in terms of energy conservation. Incidentally, this B-type silica gel also has the advantage that water can be completely removed and regenerated more easily and in a short time by magnetron electronic heating. Suitable for applying the method of the present invention are almost all fresh seafood, from frequently caught fish such as Pacific saury, horse mackerel, sardines, and herring, to high-quality fish such as sea bream, flounder, and flounder, as well as shrimp, octopus, squid, and shellfish. There is a wide range of seafood, including delicacies such as seafood, but needless to say,
If the meat is too thick, it is impractical, so it is preferable to open it and remove the internal organs, or to prepare it as a fillet so that the meat is less than 30 mm thick. However, for things like flounder and small shrimp, you can process them as they are without opening them, resulting in a beautiful, transparent finish that resembles a shell. The water absorption of silica gel is endothermic, contrary to desiccants such as calcium chloride, so the temperature and humidity on the surface of the fish decrease at the same time during dehydration, so the fish will not rot during the process. . It is, of course, desirable to store fresh seafood treated by the method of the present invention in a chilled state, but it can be stored to a considerable extent even at room temperature. Furthermore, if you want to improve the storage stability, various applications such as pre-soaking in salt water or impregnating cellophane with a freshness-preserving agent or preservative such as vitamin C can be easily applied. According to the experience of the present inventors, as a guideline for reducing the water activity of seafood by reducing water content and adding salt, in order to reduce the water activity by 0.01, it is necessary to reduce the water content by 2% or add salt. It is only necessary to increase the salt content by 2%, and since the method of the present invention allows for extremely hygienic handling, the meat can be kept sufficiently long by drying to the extent that it does not lose its freshness. For example, 80% of water
If the purpose is to dry cod to an active moisture content of 0.85 or less, conventionally it is necessary to reduce the moisture content to 50% or less, and salt-dried cod with about 5% salt added has a very high moisture content.
The drying loss is required to be 60% or less, that is, the drying loss is 50% or more. However, although this method ensures preservation,
The freshness of the meat is lost. In the method of the present invention, even if the offal is dried slowly, that is, the loss on drying is about 30%, it can be stored for a fairly long time and the product is delicious. The present invention will be explained below with reference to Examples. Example 1 30 Pacific saury and 80 small horse mackerel, each with their backs opened, internal organs removed, washed with clean water, and blood drained in 3% saline for 2 hours, each cut into appropriate size with cellophane scissors. It's crowded. On the other hand, line the bottom of the Toro box with newspaper and place B-type silica gel (product name: Silica Gel B;
(manufactured by Fuji Devinson Chemical Co., Ltd.)
The top is covered with cellophane, the above-mentioned treated fresh fish is arranged on top of it, and then multi-layered with cellophane, B-type silica gel, cellophane, fresh fish, cellophane, B-type silica gel, etc., and finally a polyethylene film is covered. put. Changes over time were as shown in the table below. The amount of silica gel used in this example is approximately the same amount per fresh fish, but the moisture absorption limit of this material at 25°C is about 165% at a relative humidity (water activity) of 0.85, so this third Can withstand 1 or 3 uses of the same amount.

[Table] The product has a good gloss and tastes like fresh fish. Fresh fish usually loses its freshness significantly if left at room temperature for 24 hours and immediately spoils, and even if stored refrigerated below 10℃, the shelf life is 3 days. However, with this product,
It will last for a long time even at room temperature, and will last for 1 week to 1 week when stored chilled.
It can be enjoyed even after several months. After use, hydrated type B silica gel can be dehydrated and regenerated by drying in the sun.
Can withstand repeated use. Example 2 Similar to Example 1 above, saury and mackerel were opened and washed, and 0.3% ascorbic acid was added to prevent oil burns.
%, immersed in a 3% salt aqueous solution for 2 hours and then taken out.
Insert into #300 cellophane. This is dehydrated by embedding it in type B silica gel granules. In either case, an excellent product with sufficient shelf life is obtained within 12 hours. Naturally, the ascites effect will vary depending on the fish species and body thickness, but in all cases, a homogeneous dry state can be obtained.
The fish body becomes transparent. The results are shown in the table below.

[Table] The amount of B-type silica gel used in this example is:
The weight was 840 g, and the weight after water absorption was 996 g (index 119). Note that since indexes from 160 to 175 can be used, the same process can be repeated three times.
This 996g of water-containing gel can be easily returned to its original size of 840g in about 22 minutes using a 480W, 2450MHz magnetron. In the case of open fish, fish meat may adhere to the cellophane depending on the conditions, but if the inner surface of the cellophane is coated with edible oil, it will easily peel off during use. In this case, the drying efficiency decreases to some extent, so it is preferable to emulsify edible oil with some film agent such as gelatin or pullulan and apply it to the inside of cellophane for better releasability, gloss, and drying properties. As the cellophane dries, its releasability improves due to its own oil and fat exudation. Example 3 As an example of using the whole fish body, 30 flatfish of different body thickness were divided into groups of 10 fish each, and each group was simply washed with clean water and sandwiched between cellophane, and the pattern of water activity decrease, applicability, and storage were examined. We considered gender, etc. The results are shown in the table below.

[Table] The body thickness of each group of fish after 48 hours is 15 mm, 12 mm,
11mm, weight index 63%, 62.7%, 57.5 respectively
%, moisture was 59% and 58.5%, respectively, from the initial 74%.
54.8% and water activity of 0.930, 0.925, and 0.905, respectively, and the thinner the drying effect, the better the drying effect, but since they are all dehydrated uniformly, they have a beautiful translucent to nearly transparent veneer shape, and after manufacturing. It has not lost its freshness even after 3 days at room temperature. However, if left at a temperature of 22 degrees Celsius, the odor will come from the internal organs, so if you want to improve preservation, it is better to remove the internal organs, and leave the eggs as is.
It can be stored in the refrigerator for more than a month. Example 4 In a similar manner, squid can be dehydrated to produce transparent dried dried squid, which can be rehydrated by boiling water or water. Note that, as described above, the easiest way to dehydrate and regenerate type B silica gel is to use a microwave oven. Dehydrating 300g of water can be achieved in about 30 minutes using 480KW and 2450MHz (megahertz), but this is as efficient as or more efficient than the free water in a pot, so in the end it is possible to dehydrate the water in seafood. It is equivalent to removing the same amount of energy at a low temperature, which is extremely energy-saving. As mentioned above, in the method for processing fresh seafood of the present invention, fresh seafood that has been handled hygienically is wrapped in cellophane, and surrounded by B-type silica gel that acts at low temperatures and high humidity. Because it dehydrates
Unlike other sun drying methods or wind tunnel drying methods, not only does it prevent bacteria from adhering and invading from the outside, but silica gel has the property of lowering the temperature when it absorbs water, and the synergistic effect of cellophane and B-type silica gel prevents dehydration. There are advantages to achieving smooth uniformity and controlling the water activity of the product accordingly. Therefore, the quality of the processed products is excellent in terms of taste, smell, and gloss, and they have a much better shelf life than fresh seafood that has just been caught.As a product, it is packaged in cellophane, so it is easy to handle. Easy and beautiful,
Not only is it resistant to oxidation and has high distribution value,
Unlike processing methods such as frozen seafood, which consume a large amount of energy during production and distribution, it is extremely energy-saving. Moreover, B-type silica gel is easy to regenerate and dehydrate, and can be used repeatedly.In particular, granular silica gel does not stain the product and does not make the hands of the user dry.

Claims (1)

[Claims] 1. Fresh seafood that has undergone pre-cleaning treatment such as removal of internal organs and washing with water is wrapped in cellophane, and the surrounding area is dehydrated using silica gel with large pore diameter and pore volume to reduce water activity. How to process fresh seafood.