Manufacturing process of fish paste products

Crushing during the manufacture of paste products

The stirring process in which salt and seasonings are added to frozen surimi and kneaded is called mashing.

In order to make a paste product with a good texture, salt is added to fish meat (frozen surimi) and rubbed to elute and hydrate salt-soluble proteins, and then starch and other auxiliary ingredients are mixed appropriately.

1. Rough surimi: Finely grind the surimi to make it easier to salt
2. Salt shavings: Add 2.0-3.2% salt to elute salt-soluble proteins
3. Powdered starch and seasoning: auxiliary ingredients are added and kneaded.
4. Finishing slip: Add water to make even kneading

Role of salt in the grinding process

In the low concentration state, the solubility (salt dissolution) is increased by adding salt, and in the high concentration state, the solubility is lowered and the dehydration aggregation (salting out) state is formed. The purpose of the salt added in the salt shaving process in the mashing process is for the salt-dissolving effect, and for the purpose of seasoning, it is about 2.0% to 3.0%.

When adding surimi by grinding, it is important to add in small amounts and evenly.

If salt is added while the ice crystals do not reach 0℃. or higher, re-ice crystals are generated, and the protein itself is denatured into small particles and solidifies.

Be careful as the coagulated protein remains in the grains and becomes rough when heated. There is no suitable method for surimi that can be applied to all paste products. There is an appropriate method for each product, and it is adjusted for each product in consideration of the properties of the surimi used, the temperature at which it is rubbed, the process after crushing, and the like.

Points to consider in the crushing process

(1) Rising temperature depending on the fish species　

Surimi made from fish that live in cold basins such as walleye pollock and southern dala, and surimi made from fish in warm basins such as Itoyori and Eso are affected by the sliding temperature and sitting temperature.
Looking at the sitting temperature, the former tends to set well at 10-40℃, and the latter tends to set in a higher temperature range of 30-40℃.

(2) Surimi grade　

As the grade of surimi from land to high-grade surimi at sea increases, you must be careful and careful about the method of crushing. In other words, if the grinding method can be properly controlled, there is a possibility of producing a product of better quality.

(3) How to thaw frozen surimi　

Frozen frozen surimi is usually stored frozen at -18 to 25℃ or below. Thaw to -3 to -1℃ before use in production. Thawing should be raised to this temperature just fore use for surimi. Thawing too early does not have a positive effect on surimi.

(4) Crushing temperature　

It is common to start the semi-thawed frozen surimi from rough surimi and gradually raise the temperature to finish surimi.
There are appropriate values for the sliding temperature for each product, such as product characteristics and the sitting method in the subsequent process. For Alaska pollack, it is generally said that it is better to keep the temperature below 15℃ as the upper limit.

(5) Salinity　

Among the formulations of surimi products, the one that has the greatest influence on fish meat protein is salt, which is the salt concentration. By controlling this salt concentration, the texture of the product can be adjusted.

(6) Salting time

When crushing with a silent cutter, salting finishes in about 5 minutes, but depending on the product, less than this is sufficient. It is related to the model of the crusher, the type of fish, the type of surimi, the salt concentration, etc. and the temperature at which it is rubbed.

(7) Amount and timing of water addition　

It is possible to control the temperature of the ice by adding water while adjusting the temperature of hot water, tap water, or ice. The working time can be shortened by adding warm water during rough cutting and using ice water from the middle to the latter half of the crushing. In addition, if the salt concentration can be adjusted appropriately, the amount of water added can be adjusted even before salting.

(8) Model of crusher　

When crushed with a mortar, it becomes an apparently hard paste. In addition, when fried tofu is molded into fried tofu, it may shrink and deform due to the large amount of fish meat components in the fibrous state.

In the case of the silent cutter, the hardness of the paste and the shrinkage of the fried product are less than those of the mortar because it is crushed to cut the fish fiber.

Crushing with a vacuum ball cutter is effective for products that use a sitting process containing high-grade surimi.　Compared to the silent cutter, it is possible to increase the amount of water added to the surimi by 3 to 5%. Suitable for crab flavored kamaboko and molded kamaboko that require degassed constitution.

（９）pH

Fish protein is strongly affected by changes in pH value. It shows good elasticity forming power at pH 6.8 to 7.3, but it becomes very strong elasticity especially at pH 7.1 to 7.2.

Specific method of crushing surimi products

(1)Set-steamed Kamaboko　

Kamaboko generally refers to a semi-circular molding on a plate. Currently, Alaska pollack frozen surimi is mainly used as a raw material, and white croaker, which is white in color and has umami, and has the ability to set, may be mixed. The color tone should be white, and the process requires the ability to set, so advanced and intermediate surimi are used.

When frozen walleye pollack surimi is used, it is better to thaw it to about -1℃ just before mashing. It is better not to raise the thawing temperature to the plus side or leave it at room temperature until it is crushed. The appropriate temperature for sliding up after crushing is 5 to 10 ° C. for low-temperature setting and 10 to 15℃. for high-temperature setting, depending on the difference in the subsequent setting process conditions.

The salt concentration in the salt shavings may be 2.0 to 2.5% if the frozen surimi used is advanced. Therefore, it is possible to add a large amount of water during rough shaving, and the salt shaving can be adjusted. Therefore, in the case of a silent cutter, the mixing time is about 5 minutes as a guide. For products that use the sitting process, the vacuum crusher has a good effect.

(2) Fried Kamaboko

  It is a common fried fish cake or burdock roll. Alaska pollack land 2nd grade, or Western upper and lower grade surimi and land Itoyori surimi are used, as well as horse mackerel, atka mackerel, sardines, hairtail, etc. As for surimi, lower grade products are generally used.

When high-grade frozen surimi is used, the elution of salt-soluble protein increases, the viscosity of the kneaded surimi increases, and film formation is likely to occur. As the fring, the bubbles inside become larger, and the gas increases due to water vapor.   When a dense film is formed by using high-grade frozen surimi, gas cannot be released, and it accumulates inside the film on the surface, increasing its volume and becoming a balloon-like swelling state.

Even when crushed using a lower-grade frozen surimi, if it is too long, the body becomes too dense, and the same swelling as when using a higher-grade frozen surimi may occur. It is better to use low-grade frozen surimi and shorten the mashing time for fried surimi.

When thawing frozen surimi, even if the temperature is on the plus side (about 0 to 4℃), it is necessary to shorten the grinding time or make adjustments, but the effect on the product is small. Since there is little sitting reaction, it is desired to reduce the range of temperature rise temperature during frying, and it is desired to harden the paste during molding, it is appropriate to raise the sliding temperature to about 10 to 15℃.

From the viewpoint of production capacity, it is common to use a siren cutter for the crusher from rough scraping to sliding up. Since the surimi crushed with a mortar may shrink or deform when fried, it is recommended to use a silent cutter to roughen the frozen surimi. When the seeds are mixed, there is almost no deformation that swells or shrinks.

Method of heating on Kamaboko

1) General properties　

Kamaboko paste is a fish protein, so it is very susceptible to heat. it is denatured under the influence of heat in various temperature ranges from 10℃ to 100℃, but it also includes temperatures that have a bad effect, especially around 60℃.

2) Slow heating and rapid heating　

The elasticity of Kamaboko varies depending on the heating method, shape and size. Even with steaming, small products can be made with stronger elasticity than large products. In general, rapid heating can make products with stronger elasticity than slow heating.

3) Suwari and modori

If the kamaboko is left at room temperature, it will change from a paste (sol) to a konjac-like gel. This is the so-called “suwari” phenomenon. If left at 60-70℃, it will gel at first, but if left unattended, it will easily collapse. This change in softening is called “modori”.

4) Strengthen the elasticity of kamaboko　

Generally, in the case of Alaska pollack frozen surimi, the paste molded in a sitting temperature range (30-40℃) lower than 50℃ is allowed to sit for a certain period of time, and after the formation of the kamaboko structure, the gel does not deteriorate much. It is recommended to heat it at a high temperature (80-98℃).

5) Purpose of heating Kamaboko

 One is to promote the sitting reaction and denature the fish meat protein to make the Kamaboko gel smooth and strong. The other is to complete sterilization, gelatinization of starch, and heat denaturation of fish meat protein by steaming.

About frying of fried sruimi products

One of the methods for heating surimi products is to fry by molding the mixed surimi and heating it with oil at least 100℃ or higher. Heat is conducted in the molded kneaded meat by oil, and fish meat protein is denatured and coagulated, and water evaporates, causing starch gelatinization phenomenon.

On the surface layer of deep-fried products, browning phenomenon occurs due to amino acids and sugars due to high temperature, and the water evaporates to replace fats and oils. In addition, a new aroma is generated by a chemical reaction, and the flavor is improved by concentrating the taste.

The difference between frying and boiling depending on the heating method is that the outflow of umami ingredients is small in frying. The difference between fried and steamed heating methods is that fried heats at a faster rate and has a concentrated taste.

The difference between the heating method of frying and baking is that the temperature applied to the surface is lower than that of frying, the temperature transmitted to the inside is also lower, and the heating is average. In the case of deep-fried food, the inside of the product is heated by saturated steam, which is similar to steaming.

Purpose of frying

(1) Heat sterilization　

Bacteria must be sterilized in the kneaded raw meat. Heat to reach a core temperature of 75-80℃.

(2) Gelling of mixed meat　

By heating, coagulation and denaturation of fish protein in the product and gelation by gelatinization of starch are completed.

(3) Deep-fried color development

Each product has a proper fried color. Control the composition method, oil temperature and frying time according to the purpose.

(4) Add flavor　

The flavor is improved by being heated in high temperature oil.

Additives for deep-fried color

Deep-fried color development is also called an amino-carbonyl reaction with amino acids and sugars. Adjust with the additives in the formulation, oil temperature and frying time.

(1) Glucose　

It is an indispensable additive for deep-fried food. The color tone is orange, which is typified by the most common deep-fried Satsuma-age, and it develops well at an oil temperature of 170-180℃. 1.0-2.0% is added in the formulation.

(2) Xylose

It is used when you want a bright fried yellow to fox color. At an oil temperature of 160-170℃, it has a characteristic bright fried color, but at 170℃ or higher, it becomes an orange color similar to glucose.

(3) Fermented seasoning　

It is also used for fried color because it contains a lot of amino acids and sugars. Mirin is especially effective and has been used as a seasoning for deep-fried oranges since ancient times.

Grilled Kamaboko

In general, it includes everything that is “baked” in the heating process. Here, we will focus on the representative chikuwa as a product that heats the mixed surimi by grilling it over an open flame.

Process of producing Chikuwa

Baking of surimi products

The heating method of “baking” is heating in a gas at 200 to 350℃, which is higher than steaming or frying. It is not good in terms of thermal efficiency, but it is the best way to bring out the characteristics of the raw materials. The surface is moderately charred and the inside is moderately cooked. This is good baking.

Purpose of baking

(1) Molded body “suwari” promotion action　

When the mixed surimi paste to a “suwari” process by steam or heat from the lower part of the chikuwa baking machine, a supple and elastic chikuwa is formed. It is an important factor for quality when making high-quality chikuwa with a celastic texture.

(2) Moderate drying of the product surface

If the surface is slightly dried after the “suwari” process and before grilling on an open flame so that it does not stick to the touch with fingers, the color will be easily browned. The thickness of the grilled skin can be adjusted by controlling the degree of dryness.

(3) Final gelation of surimi paste

It has the meaning of heating and coagulating like steaming and fried surimi products.

(4) Heat sterilization

It is as important as the purpose of heat treatment as well as steaming and fried surimi products.

(5) Burning color　

Add a brown color to the appearance that is evidence of burning with a burner after the “suwari” process. Corresponding to the desired baking color, the color is developed by adjusting the composition, heating, and baking time.

6) Add grilled flavor

Add a savory roasted flavor that is unique to roasting. If it is too strong, it will feel burnt, and if it is too weak, it will feel foreign, so delicate adjustment is required.