The use of freshwater and seawater to produce low-value trash fish products is an important source for people to obtain fish-type foods. It is well-received by consumers due to factors such as convenient consumption, good taste, and simple cooking.
However, at present, the variety of fish and fishery products is monotonous, and the quality of products needs to be improved, which greatly limits the consumption of surimi products. To this end, domestic and foreign researchers have conducted research on increasing the variety of surimi products and improving the quality of surimi products, and have achieved a lot of results.
The main indicators for measuring the quality of surimi products are elasticity, taste, texture, and shape, among which the elasticity of products is an important indicator of the quality of surimi products. The salt-soluble protein, myofibrillar protein, in fish muscle is the main ingredient in the formation of elastic gels in fish meat and is an important source of product elasticity.
Muscle fibril protein in fish muscle is a salt soluble protein. Under the action of salt, myofibrillar thick filaments and filaments begin to dissolve. Its main components, myosin and actin, absorb a large amount of water and combine to form muscle action. Globular sol. This sol slowly forms an elastic gel at a low temperature.
The level of gel strength of fish protein elastic gel is a key factor in determining the quality of fish meat products, directly affecting the tissue properties, water retention, adhesion and product yield of the fish products. Although the gel strength of different fish species is different, some measures to increase the gel strength can be used to improve the elasticity of the fish gill products.
The processing process of fish surimi products can be decomposed into the process of raw fish roasting, the process of adding supplementary materials and heating, and if frozen surimi is used as raw material, it also includes the process of frozen surimi and the thawing process of surimi. In this paper, based on the various processing processes of fish gizzard products, the measures for improving the gel strength of fish meat are introduced to guide the development of new products for fish gizzard products and the improvement of product quality.
1. Rinsing and rinsing after the fish is taken is a very important processing step after the fish is taken. The rinsing not only removes colored substances and odor components from the fish meat, but also improves the gel strength of the fish protein gel. The rinsing process removes water-soluble proteins (such as sarcoplasmic proteins) from the fish meat. This protein contains many proteolytic enzymes, and its presence affects the formation of the gel. Different rinsing methods have an effect on the gel strength of fish protein, sometimes affecting the yield of the product. For example, rinsing with a low concentration of saline solution removes sarcoplasmic protein while also accompanied by the loss of part of the myofibrillar protein, resulting in a reduced rate. Saeki et al. believe that the rinsing with CaCl rinses can greatly improve the fish gel characteristics because the Ca2+ ions in the rinse play a role in enhancing the three-dimensional network structure of myofibrils.
2. Adding anti-freezing agent when fish meat is frozen. Before the gelling of fish meat, it usually takes a frozen or refrigerated process, which often causes the degeneration of fish protein, leading to the decrease of Ca2+-ATPase activity and gel strength. An effective measure to prevent denaturation of fish protein is to add antifreeze denaturants (antifreeze). Antifreeze agents are sucrose, sorbitol, complex phosphates, and oligosaccharides. Japanese scholar Yamaguchi Atsuko's research results showed that the addition of polyphosphate and sorbitol at the same time in fish gizzards can improve the gel strength and is better than using sorbitol alone, such as the addition of complex phosphate (tripolyphosphate sodium, Sodium pyrophosphate, sodium hexametaphosphate, etc.) can improve the water holding capacity of fish gills and prevent the loss of water and taste substances.
3. Adding reducing substances in the early stage of the gel. Adding some reducing substances in the early stage of the gel to inhibit the oxidation of the sulfhydryl groups to disulfide bonds, and restore the activity of the cold-thawed denatured protein. Shann et al.'s experimental results confirmed that the addition of a reducing agent (such as 0.08%--0.10% of mercaptoethanol, sodium bisulfate, etc.) to the guanidine-recovery activity of the partially oxidized sulfhydryl group in the frozen and stored squid and squid protein was performed earlier in the surimi gel. The recovery level reached 83%--98%.
4. Adding a gel enhancer Before gelling fish protein, adding a gel strength enhancer is an effective way to increase gel strength. Ca2+ plays an important role in the gel strength of fish protein. Calcium ion activates transglutaminase (TGase) in fish protein gel process, and then catalyzes γ-carboxamide groups in glutamic acid residues and others. Amino acid residues crosslink and form a stronger network through covalent bonds.
For fish species with less transglutaminase (TGase) content in fish, such as freshwater fish such as squid, microbial BTGase can be added to improve its gel formation energy. The mechanism of TGase-induced reorganization of fish protein is: TGase catalyzes the cross-linking of the γ-carboxyamido glutamic acid γ-carboxyl amide with the lysine Lys residue ε-amino, resulting in the intramolecular or intermolecular ε - The bridging binding of (γ-Glu)Lys forms a cross-linked protein structure, and the gel strength of the gel increases with increasing TGase content.
The addition of starch to the fish meat can reinforce the gel. The mechanism of starch action is that when heated gelatinized, the free water is absorbed into the passivated water by the added starch. Since the mechanical strength of the swollen gelatinized particles is greater than that of the fish, the elasticity of the fish is reinforced and the gel strength is improved. Vegetable protein, gelatin, egg white and other substances are also elastic enhancers for fish products.
5, fish smashing (smashing) method smashing or smashing is one of the important processes in the production of surimi products, fish puckering mode of fish protein gel strength is also more significant. The smashing process is divided into three stages: empty squatting, salt simmering and seasoning smashing. The empty smashing further destroys the muscle fibrous tissue of the fish and creates a good condition for the complete dissolution of salt-soluble protein. Salt mash makes the fish in a dilute salt solution. The salt-soluble protein was fully eluted to form a highly viscous fish-paste sol, and seasonings were collapsed so that the added ingredients, seasonings, and gel enhancer were thoroughly mixed with the fish-paste sol. The collapse process should control the collapse time, the collapse temperature, and the amount of salt to ensure the elasticity of the surimi products.
6. Adding oxidants near the end of licking The addition of potassium chromate, hydrogen peroxide, cystine, deoxyascorbic acid, and other substances to the mash can promote the formation of elastic gels, which can make the -SH group of the protein (sulfhydryl) Oxidation forms SS bridges (disulfide bonds) between its molecules, strengthening the network structure.
7. The multi-stage gelation method used in the gelatinization of fish protein, the effect of low-temperature gelation is better than high-temperature gelation, but gelation at low temperature requires too much time and is not suitable for industrial production. Two-stage gelation was used. In order to avoid the gel degradation temperature, the low temperature gelation temperature is usually taken at 30°C--50°C, and the high temperature gelation temperature is at 75°C--95°C, and the gel process rapidly passes through the gel to degrade the temperature zone.
The formation of fish protein elastic gel is the basis for the elasticity of fish gill products. According to the gelatinization mechanism of fish protein, a variety of measures are used to achieve the purpose of providing the quality of gizzard products. The mechanism of fish protein gel has yet to be explored, and measures to improve the gel strength of fish need to be further studied.
However, at present, the variety of fish and fishery products is monotonous, and the quality of products needs to be improved, which greatly limits the consumption of surimi products. To this end, domestic and foreign researchers have conducted research on increasing the variety of surimi products and improving the quality of surimi products, and have achieved a lot of results.
The main indicators for measuring the quality of surimi products are elasticity, taste, texture, and shape, among which the elasticity of products is an important indicator of the quality of surimi products. The salt-soluble protein, myofibrillar protein, in fish muscle is the main ingredient in the formation of elastic gels in fish meat and is an important source of product elasticity.
Muscle fibril protein in fish muscle is a salt soluble protein. Under the action of salt, myofibrillar thick filaments and filaments begin to dissolve. Its main components, myosin and actin, absorb a large amount of water and combine to form muscle action. Globular sol. This sol slowly forms an elastic gel at a low temperature.
The level of gel strength of fish protein elastic gel is a key factor in determining the quality of fish meat products, directly affecting the tissue properties, water retention, adhesion and product yield of the fish products. Although the gel strength of different fish species is different, some measures to increase the gel strength can be used to improve the elasticity of the fish gill products.
The processing process of fish surimi products can be decomposed into the process of raw fish roasting, the process of adding supplementary materials and heating, and if frozen surimi is used as raw material, it also includes the process of frozen surimi and the thawing process of surimi. In this paper, based on the various processing processes of fish gizzard products, the measures for improving the gel strength of fish meat are introduced to guide the development of new products for fish gizzard products and the improvement of product quality.
1. Rinsing and rinsing after the fish is taken is a very important processing step after the fish is taken. The rinsing not only removes colored substances and odor components from the fish meat, but also improves the gel strength of the fish protein gel. The rinsing process removes water-soluble proteins (such as sarcoplasmic proteins) from the fish meat. This protein contains many proteolytic enzymes, and its presence affects the formation of the gel. Different rinsing methods have an effect on the gel strength of fish protein, sometimes affecting the yield of the product. For example, rinsing with a low concentration of saline solution removes sarcoplasmic protein while also accompanied by the loss of part of the myofibrillar protein, resulting in a reduced rate. Saeki et al. believe that the rinsing with CaCl rinses can greatly improve the fish gel characteristics because the Ca2+ ions in the rinse play a role in enhancing the three-dimensional network structure of myofibrils.
2. Adding anti-freezing agent when fish meat is frozen. Before the gelling of fish meat, it usually takes a frozen or refrigerated process, which often causes the degeneration of fish protein, leading to the decrease of Ca2+-ATPase activity and gel strength. An effective measure to prevent denaturation of fish protein is to add antifreeze denaturants (antifreeze). Antifreeze agents are sucrose, sorbitol, complex phosphates, and oligosaccharides. Japanese scholar Yamaguchi Atsuko's research results showed that the addition of polyphosphate and sorbitol at the same time in fish gizzards can improve the gel strength and is better than using sorbitol alone, such as the addition of complex phosphate (tripolyphosphate sodium, Sodium pyrophosphate, sodium hexametaphosphate, etc.) can improve the water holding capacity of fish gills and prevent the loss of water and taste substances.
3. Adding reducing substances in the early stage of the gel. Adding some reducing substances in the early stage of the gel to inhibit the oxidation of the sulfhydryl groups to disulfide bonds, and restore the activity of the cold-thawed denatured protein. Shann et al.'s experimental results confirmed that the addition of a reducing agent (such as 0.08%--0.10% of mercaptoethanol, sodium bisulfate, etc.) to the guanidine-recovery activity of the partially oxidized sulfhydryl group in the frozen and stored squid and squid protein was performed earlier in the surimi gel. The recovery level reached 83%--98%.
4. Adding a gel enhancer Before gelling fish protein, adding a gel strength enhancer is an effective way to increase gel strength. Ca2+ plays an important role in the gel strength of fish protein. Calcium ion activates transglutaminase (TGase) in fish protein gel process, and then catalyzes γ-carboxamide groups in glutamic acid residues and others. Amino acid residues crosslink and form a stronger network through covalent bonds.
For fish species with less transglutaminase (TGase) content in fish, such as freshwater fish such as squid, microbial BTGase can be added to improve its gel formation energy. The mechanism of TGase-induced reorganization of fish protein is: TGase catalyzes the cross-linking of the γ-carboxyamido glutamic acid γ-carboxyl amide with the lysine Lys residue ε-amino, resulting in the intramolecular or intermolecular ε - The bridging binding of (γ-Glu)Lys forms a cross-linked protein structure, and the gel strength of the gel increases with increasing TGase content.
The addition of starch to the fish meat can reinforce the gel. The mechanism of starch action is that when heated gelatinized, the free water is absorbed into the passivated water by the added starch. Since the mechanical strength of the swollen gelatinized particles is greater than that of the fish, the elasticity of the fish is reinforced and the gel strength is improved. Vegetable protein, gelatin, egg white and other substances are also elastic enhancers for fish products.
5, fish smashing (smashing) method smashing or smashing is one of the important processes in the production of surimi products, fish puckering mode of fish protein gel strength is also more significant. The smashing process is divided into three stages: empty squatting, salt simmering and seasoning smashing. The empty smashing further destroys the muscle fibrous tissue of the fish and creates a good condition for the complete dissolution of salt-soluble protein. Salt mash makes the fish in a dilute salt solution. The salt-soluble protein was fully eluted to form a highly viscous fish-paste sol, and seasonings were collapsed so that the added ingredients, seasonings, and gel enhancer were thoroughly mixed with the fish-paste sol. The collapse process should control the collapse time, the collapse temperature, and the amount of salt to ensure the elasticity of the surimi products.
6. Adding oxidants near the end of licking The addition of potassium chromate, hydrogen peroxide, cystine, deoxyascorbic acid, and other substances to the mash can promote the formation of elastic gels, which can make the -SH group of the protein (sulfhydryl) Oxidation forms SS bridges (disulfide bonds) between its molecules, strengthening the network structure.
7. The multi-stage gelation method used in the gelatinization of fish protein, the effect of low-temperature gelation is better than high-temperature gelation, but gelation at low temperature requires too much time and is not suitable for industrial production. Two-stage gelation was used. In order to avoid the gel degradation temperature, the low temperature gelation temperature is usually taken at 30°C--50°C, and the high temperature gelation temperature is at 75°C--95°C, and the gel process rapidly passes through the gel to degrade the temperature zone.
The formation of fish protein elastic gel is the basis for the elasticity of fish gill products. According to the gelatinization mechanism of fish protein, a variety of measures are used to achieve the purpose of providing the quality of gizzard products. The mechanism of fish protein gel has yet to be explored, and measures to improve the gel strength of fish need to be further studied.