Method for enhancing gel property and stability of minced fillet by alkaline electrolyzed water

Abstract

The invention discloses a method for enhancing gel characteristics and stability of minced fillet by alkaline electrolyzed water. The method comprises the following steps: pretreating fish, cutting into blocks, and crushing to obtain crushed fish meat; placing the minced fish meat in a purified water tank with tap water for electrolytic rinsing for 1-9 min; tap water in the purification water tank is controlled to be alkaline water with the pH value of 7.50-9.30; controlling the water content in the minced fish meat after electrolysis rinsing to be 78 + / -5%, so as to obtain minced fish; adding table salt into the minced fillet, and chopping and mixing to obtain raw pulp minced fillet; adding glutamine transaminase into the minced fillet with the raw pulp, and chopping to obtain minced fillet raw pulp; shaping the minced fillet raw slurry in a mold, and then heating; the minced fillets are rinsed by the purification water tank electrolysis alkaline water production equipment, fishy smell substances in the minced fillets are reduced, the gel characteristic of the minced fillets is enhanced, the stability of the minced fillets in the freezing process is facilitated, the method is safe and green, and the treatment cost is relatively low.

Description

Technical Field

[0001] The invention relates to a surimi gel, in particular to a method for enhancing the properties and stability of the surimi gel by using alkaline electrolyzed water, and belongs to the technical field of novel food purification and surimi gel strengthening. Background Art

[0002] The deep processing of aquatic products is an important part of the development of the marine economy, and the processing of marine raw pulp products is one of the important contents to promote the economic development of aquatic products. In recent years, traditional marine raw pulp products have become more and more popular among consumers in the market, such as fish slips, fish paste and fish balls. Fish meat can be processed by deboning, cleaning, grinding, rinsing and other treatments to obtain raw pulp raw materials, which are further salted, shaped and heated to obtain fish paste products. In the entire production process, a breakthrough in the key step of rinsing is extremely important for improving the flavor of fish paste raw materials and improving the quality of future marine raw pulp products.

[0003] In 2009, the acid-base method has been proven to significantly improve the gel strength of silver carp surimi. The main process is to place the surimi in an extremely acidic or alkaline environment to change the structure of myofibrillar protein and obtain a new type of acid-base surimi. This type of method often uses hydrochloric acid or sodium hydroxide as raw materials to improve the storage stability of surimi. Studies have shown that in an alkaline environment, fat in fish meat can be removed, the production of polyunsaturated fatty acid oxidation degradation products can be reduced, and the fishy substances in fish meat can be reduced. The alkaline environment can promote the unfolding of fish meat myofibrillar protein, and the oil floats in the upper layer, the soluble protein gathers in the middle layer, and the insoluble matter such as fish bones and fish skin is concentrated in the lower layer. The alkaline surimi is obtained by centrifugation through isoelectric precipitation of myofibrillar protein.

[0004] Chinese invention patent CN110074357B discloses a surimi product with high gel strength and nutritional value and its preparation method, which uses an acid-base method to prepare a complex of high-amylose corn starch and fatty acids. After the frozen surimi is thawed, it is chopped for 3 minutes, 2.5% salt is added and chopped for 3 minutes, 2% to 3% starch-fatty acid complex is added, the moisture content is adjusted to 78%, and the chopped for 5 minutes, and then poured into a casing with a diameter of 25 mm, and heated at 0.12 MPa and 121°C for 20 minutes to obtain a surimi product with high gel strength and nutritional value. The single helical structure of the amylose in this technology wraps the carbon chain of the fatty acid inside, avoiding its contact with external oxygen and preventing the oxidation and rancidity of the fatty acid; the acid-base method of this technology can change the structure of starch and be used to wrap fatty acids to improve the effect. This technology uses strong hydrochloric acid with a pH of 2 and sodium hydroxide with a pH of 12 as acid-base treatment, which changes the pH of the surimi system to induce chemical changes in the protein, such as deamidation, denaturation, dissolution or precipitation. This direct way of controlling pH is essentially achieved through chemical reactions. Strong acids and strong bases are highly corrosive and irritating, and strict safety precautions are required during operation, otherwise they may cause harm to workers and equipment. In addition, acid-base treatment may bring unnatural taste or odor, affecting the flavor of the final product. Moreover, in the process of adjusting the acid and base, acidic or alkaline wastewater may be generated. Improper treatment may cause environmental pollution and require additional wastewater neutralization treatment. Strong acids and strong bases are highly corrosive to treatment equipment, and long-term use may increase equipment maintenance and replacement costs. Summary of the invention

[0005] In order to solve the technical deficiencies of the harm to the environment and human health caused by the hydrochloric acid and sodium hydroxide introduced in the preparation of surimi raw pulp products by the acid-base method, the purpose of the present invention is to provide a method for enhancing the gel properties and stability of surimi by alkaline electrolyzed water, which is safe, green, has relatively low processing cost, effectively reduces the fishy odor components in the rinsing process, and improves the gel strength and frozen storage stability of surimi raw pulp.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solutions:

[0007] A method for enhancing the gel properties and stability of surimi by alkaline electrolyzed water comprises the following steps:

[0008] Step 1: pre-treat the fish, cut it into pieces, and mince it to obtain minced fish meat;

[0009] Step 2: Place the minced fish meat in a purified water tank with water for electrolytic rinsing for 1-9 minutes; control the water in the purified water tank to be alkaline water with a pH value of 7.50-9.30;

[0010] Step 3: Control the moisture content of the minced fish meat after the electrolytic rinsing in step 2 to be 78±5%, thereby obtaining minced fish;

[0011] Step 4: Add salt to the minced fish, chop and mix to obtain raw minced fish;

[0012] Step 5, adding glutamine aminotransferase (MTGase) to the raw fish paste, chopping and mixing, and obtaining raw fish paste;

[0013] Step 6: shaping the surimi slurry in a mold and then heating it to obtain surimi gel.

[0014] To further achieve the purpose of the present invention, preferably, the pretreatment is to remove the scales, bones, bones and skin of the fish to obtain the white meat part as the raw material for producing surimi.

[0015] Preferably, the mincing is carried out in a meat grinder at a speed of 2000-5000 r / min for 1-5 min.

[0016] Preferably, the output power of the purified water tank is 380-550W; and the water in the purified water tank is tap water.

[0017] Preferably, in the second control step, the water content in the minced fish meat after electrolytic rinsing is controlled by measuring the water content in the minced fish meat after electrolytic rinsing with a water activity meter and then adding ice water.

[0018] Preferably, the amount of salt added is 1.0-2.5% of the mass of the fish in step 1.

[0019] Preferably, the added amount of the transglutaminase (MTGase) is 1-5u / g.

[0020] Preferably, the chopping time in step 4 and step 5 is 1-5 min.

[0021] Preferably, the heating is first placed in a constant temperature water bath at 40-45°C for 30-60 min, and then transferred to a constant temperature water bath at 85-90°C for 30-60 min.

[0022] Preferably, the surimi gel with gel properties and stability is used for making fish cakes, fish sticks, fish balls or fish cakes.

[0023] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0024] 1) The present invention uses alkaline water from a purified water tank to cooperate with transglutaminase to treat the fish paste, which has obvious advantages in viscoelasticity, volatile components, and freeze-thaw performance tests compared with ordinary alkaline water combined with transglutaminase to treat the fish paste, or alkaline water from a purified water tank alone to treat the fish paste.

[0025] 2) The alkaline water produced by the electrolysis process of the purified water tank of the present invention has abundant free hydroxyl groups, which can promote the unfolding of proteins, expose more hydrophobic amino acid residues, lead to the rearrangement of protein structure, and enhance the orderliness and stability of proteins. The ordered gel network promotes the release of fishy substances inside the surimi and reduces the accumulation of lipid hydroperoxides. The key fishy substances 1-butanol, tridecane, hexanal, octane, 4-methyl- and 1-octen-3-ol are eliminated, and the quality of the surimi raw materials is improved.

[0026] 3) The present invention uses alkaline water generated by the electrolysis process of the purified water tank to promote hydrogen bonds and hydrophobic interactions within the protein, which has more stable protein functional characteristics, further improves the gel properties of the surimi, and reduces the structural damage of the surimi during the frozen storage process. While solving the problem of fish resource accumulation and storage, it is also useful to promote the development of new surimi products.

[0027] 4) The alkaline water used in the present invention is prepared from original tap water in a water tank with a certain catalytic effect in a purified water tank. Compared with the fish paste obtained by rinsing with up to 6 mol / L HCl or 6 mol / L NaOH acid-base method, it has the characteristics of being green, safe and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The graph is a graph showing the rheological properties of the fish paste in Example 1 and Comparative Examples 1, 2, and 3 as the temperature changes.

[0029] Figure 2 The figure is a graph showing the changes in volatile substances in the surimi in Example 2 and Comparative Examples 1, 2, and 3.

[0030] Figure 3 The graph is a graph showing the change in gel strength of surimi in Example 3 and Comparative Examples 1, 2, and 3 as the frequency changes. DETAILED DESCRIPTION

[0031] In order to better understand the present invention, the present invention is further described below in conjunction with the accompanying drawings and embodiments, but the embodiments of the present invention are not limited thereto.

[0032] In existing electrolyzed water research, acidic electrolyzed water is often used to treat food to achieve the purpose of increasing shelf life, etc.; alkaline electrolyzed water is considered to be healthy drinking water, and it plays a great role in cleaning residual pesticides in fruit trees, removing fishy smells in meat, and resisting plant diseases and insect pests. Chinese invention patent CN 113180186B discloses technical measures for alkaline electrolyzed water to improve the viscoelasticity of dough gluten network. Food-grade potassium carbonate is used, and alkaline electrolyzed water with no sodium ion content in the pH range of 9.5-13.0 is obtained by electrolysis in an alkaline water generator and membrane filtration. The antioxidant and strong permeability of alkaline electrolysis are used to help the formation of gluten network; the specific method is to mix an appropriate amount of liquid monocaprylic acid glyceride with the obtained alkaline electrolyzed water, add it to wheat flour and mix it in vacuum. However, the alkaline electrolyzed water currently used is extremely unstable. The OH- ions in the alkaline electrolyzed water easily react with carbon dioxide in the air to generate carbonate ions or bicarbonate ions, which reduce the pH value of water. Alkaline electrolyzed water will gradually lose its original alkalinity in an open environment. Although sealing treatment has a certain delaying effect, its effect is weak because it involves handling materials in and out and the treatment time is short.

[0033] Existing electrolysis equipment often focuses on studying the acidity and alkalinity of electrolysis products. When applied to food, they are usually treated by soaking. The soaking process may weaken the pH value of the alkaline water, making its effect poor, and the entire treatment process is also relatively time-consuming.

[0034] With the continuous advancement of consumers' health awareness and the advantages of alkaline water, it is expected that the production of alkaline water will be optimized through the renewal and transformation of equipment, so that it can achieve the purpose of sustainable production of alkaline water, so as to achieve more green, environmentally friendly and safe advantages. Among them, China Food (Beijing) Food Purification Technology Development Co., Ltd. launched a food purification industrial equipment (CN204579756U) in 2015, which has now developed into a water catalyst generator self-cleaning device for food purification machines (CN209476793U). The development of similar equipment is conducive to the realization of alkaline electrolyzed water in the industrial processing of food. According to the needs of consumers, purchase water catalyst electrolysis equipment of corresponding specifications at home.

[0035] The tank body of the purified water tank of the present invention is made of titanium dioxide material, and an electrolytic water generator is installed on the side of the tank. The interior of the device mainly includes an electrolytic component containing a positive and negative electrode exchange and an LED ultraviolet light. The titanium dioxide purified water tank has excellent photocatalytic properties, can absorb light energy in the ultraviolet light region, excite electron-hole pairs, and drive the cracking of water. In addition, the titanium dioxide material has high durability, reduces the maintenance and replacement costs of the equipment, and can also effectively reduce the overall energy consumption of the treatment process. After tap water is injected into the purified water tank, turn on the power supply to start the electrolysis process. As the electrolysis time increases, the water in the purified water tank is bombarded by the LED photocatalysis and electric energy from the linked generator, causing it to undergo continuous cracking, resulting in the pH value of the tap water in the tank showing a trend of gradual increase, and the free hydroxide ions in the tank gradually reach a saturated state, so that its pH value is stabilized in an alkaline environment. Conventional electrolysis is a process that uses electric current to decompose water into hydrogen and oxygen, which increases the cost of applying external electrical energy to drive the reaction and has relatively high energy consumption. In addition, conventional electrolysis technology requires the addition of complex reactants to effectively achieve the cleaning effect.

[0036] Preferably, the purification water tank used in the embodiment of the present invention is a food safety professional food purification water tank, model BSA-C603S / S, with an output power of 380-550W. At present, the purification water tank is mainly used for the inactivation of microorganisms in food, the degradation of Chinese medicine residues and agricultural residues in fruits and vegetables, the degradation of hormones and antibiotics in food meat, and the maintenance of the shelf life of fruits and vegetables. The main working principle of the food safety professional food purification water tank is to use a purification water tank prepared by containing metal oxides, semiconductors or other compounds with catalytic properties as a medium, and use light energy and electrical energy to drive the water to crack in the tank in the power-on state to produce a large amount of aqueous solution containing hydroxide ions. Ordinary electrolysis of water uses the electrodes of the electrolytic cell to provide current, and decomposes water molecules to form hydrogen and oxygen by directly applying current. The water purification tank of the present invention uses light energy and electric energy as water splitting media. Under different time conditions, different numbers of free hydroxide ions exist in the aqueous solution. Although the number of free hydroxide ions in the present invention is related to the electrolysis time, the pH is lower than that of ordinary electrolyzed water. For example, at the beginning of electrolysis, the pH of the solution is 7.1±0.0, and it reaches 7.5±0.0 after one minute of electrolysis, and 8.4±0.0 after three minutes of electrolysis. After 5 minutes of electrolysis, it is basically stable at 9.3±0.1. Even if it is electrolyzed for 10 minutes, there is basically no change. The pH of ordinary electrolyzed water is above 9.5, and the pH is basically above 10 when the better effect is applied. Moreover, the method of using the alkaline water formed by the water purification tank of the present invention is to place the material in the tank before the tap water is electrolyzed, and then conduct electrolysis on this basis. The minced fish meat in the electrolysis process is affected by hydroxide ions, electric waves generated by electric energy, and light. The common electrolysis process mainly uses electric current to act on water molecules with positive and negative electrodes, and uses potassium salt as electrolyte to electrolyze them to produce hydroxide ions, which are then used to soak materials. Although both are electrolysis of water, their entire mode of action, effect and mechanism of action are very different.

[0037] In the present invention, the alkaline electrolyzed water treated by the purified water tank increases the solubility of the surimi protein, promotes more myosin and MTGase to cross-link, exposes more hydrophobic structures on the surface of the myofibrillar protein after the alkaline electrolyzed water treatment, promotes the formation of more disulfide bonds between the protein and MTGase, improves the quality characteristics of the surimi gel, and reduces the loss of flavor during processing, which is of great significance for removing undesirable volatile flavors. The present invention uses the alkaline electrolyzed water treated by the purified water tank to act on the surimi to form a more compact and orderly structure on its surface, increases the content of bound water in the surimi, retains more water in the gel, and promotes the maintenance of the quality of the surimi during the frozen storage process.

[0038] Prior art research shows that rinsing fish meat with an acid-base method can obtain a surimi product with better gel properties than rinsing with cold water. Based on the weak alkalinity, stability and safety of alkaline electrolyzed water, the present invention finds that the surimi raw material obtained by this technology has stronger gel properties than that obtained by rinsing with cold water, and rinsing can be completed by only one electrolysis device (purification tank), eliminating the use of high-concentration chemical reagents of up to 6 mol / L HCl or 6 mol / L NaOH in the prior art, ensuring the safety of surimi production and processing. The present invention uses a purified water tank to provide a green, safe, efficient and sustainable surimi rinsing method, which greatly maintains the quality of surimi raw pulp while ensuring its safety.

[0039] The present invention only uses pomfret as a representative, and the method of the present invention is applicable to any fish species. The purification tank in the embodiment uses a professional food purification tank of Baoshian, model BSA-C603S / S.

[0040] Test Method

[0041] GC-MS determination of changes in fishy odor substances: weigh 3g of surimi, put it into a headspace sample bottle, add 6g of saturated sodium chloride solution and rotor, and seal it with plastic wrap. Put the sample into a magnetic heating stirrer and heat it at 55℃ for 15min. Insert the activated extraction head for adsorption for 35min, and immediately insert it into the injection port for analysis for 5min after taking it out. Gas chromatography conditions: carrier gas helium, injection port temperature 250℃, non-split injection, flow rate 1mL / min, chromatographic column heating program: start at 40℃ for 3min, increase to 100℃ at a rate of 5℃ / min, maintain at 100℃ for 3min, and then increase to 250℃ at a rate of 5℃ / min, and maintain for 3min. Mass spectrometry conditions: interface temperature 280℃, ion source temperature 230℃, quadrupole temperature 150℃, ionization mode EI, electron energy 70eV, scanning range 30-550amu.

[0042] Rheological properties: Place the sample on the calibrated AR2000ex rheometer platform and seal with paraffin to prevent the sample from evaporating. The clamp diameter is 40mm parallel plate, and the parallel plate spacing is 1mm. Perform temperature scanning. The temperature rise range is 20-90℃, and the temperature is kept at 90℃ for 20min. The heating rate is 5℃ / min, and the oscillation frequency is 1Hz. The change of elastic modulus G' with temperature during the heating process is measured. The frequency scanning range is 1-100Hz, and the change of elastic modulus G' with frequency during the heating process is measured.

[0043] Gel strength test: A texture analyzer was used to determine the changes in the gel strength of surimi after different freeze-thaw times. The test parameters were set as follows: a P36 cylindrical probe was used, the probe movement speed was set to 1 mm / s, and the test distance was 4 mm.

[0044] Example 1

[0045] A method for enhancing the gel properties and stability of surimi using alkaline electrolyzed water comprises the following steps: descaling, debone, deskinning, and cutting a silver pomfret into small pieces, and placing the pieces in a meat grinder for 1 minute to grind the pieces; placing 500 g of the ground fish meat in a purified water tank (a professional food purification water tank for food safety) with 5 L of tap water for electrolysis for 1 minute, and the output power of the electrolysis process is 380 W; at this time, the pH value of the water in the purified water tank is 7.55. The water activity value of the surimi raw pulp after rinsing and filtering the water is measured by a water activity meter at 60%, and 460 mL of ice water is added to control the water content of the fish meat to be maintained at 78%. Add 1.0% salt of the mass of the silver pomfret and continue to chop and stir for 2 minutes to obtain a surimi raw pulp product. Add 1u / g MTGase to the obtained surimi raw pulp product, chop and stir for 1 minute, and then shape it. The shaped raw pulp product was heated in a constant temperature water bath at 45°C for 45 minutes and then transferred to a constant temperature water bath at 85°C for 60 minutes to obtain a surimi gel. The rheological properties of the surimi during the heating process of the sample in Example 1 were measured to evaluate the gel viscoelasticity of the sample. Figure 1 .

[0046] Example 2

[0047] A method for enhancing the gel properties and stability of surimi by alkaline electrolyzed water comprises the following steps: descaling, debone, deskinning, and cutting a silver pomfret into small pieces, and placing the pieces in a meat grinder for 2.5 minutes to grind the pieces; placing 800 g of the ground fish meat in a purified water tank (food safety purified water tank) with 10 L of tap water for electrolysis for 9 minutes, wherein the output power of the electrolysis process is 550 W, and the pH value of the prepared electrolyzed water is 9.20. The water activity value of the surimi raw pulp after rinsing and filtering the water is 60% by a water activity meter, and 1100 mL of ice water is added to control the water content of the fish meat to be maintained at 83%. 2.5% salt of the mass of the silver pomfret is added and the mixture is chopped and stirred for 1 minute to obtain a surimi raw pulp product. 5 u / g MTGase is added to the obtained surimi raw pulp product, and the mixture is shaped after chopped and stirred for 5 minutes. The shaped raw pulp product was heated in a constant temperature water bath at 43°C for 30 minutes and then transferred to a constant temperature water bath at 88°C for 45 minutes to obtain the fish paste gel. The gel strength and flavor component changes of the samples in Example 2 were measured to evaluate the effect of alkaline water rinsing on the fish paste gel properties and the changes in volatile substances. Figure 2 .

[0048] Example 3

[0049] A method for enhancing the gel properties and stability of surimi by alkaline electrolyzed water comprises the following steps: descaling, debone, deskinning, and cutting a silver pomfret into small pieces, and placing the pieces in a meat grinder for 5 minutes to grind the pieces; placing 700 g of the ground fish meat in a purified water tank (food safety purified water tank) with 15 L of tap water for electrolysis for 5 minutes, wherein the output power of the electrolysis process is 480 W, and the pH value of the prepared electrolyzed water is 8.44. The water activity value of the raw surimi pulp after rinsing and filtering the water is 60% by a water activity meter, and 700 mL of ice water is added to control the water content of the fish meat to be maintained at 80%. 1.5% salt of the mass of the silver pomfret is added and the mixture is chopped and stirred for 5 minutes to obtain a raw surimi pulp product. 2.5 u / gMTGase is added to the obtained raw pulp product, and the mixture is shaped after chopped and stirred for 2 minutes. The shaped raw pulp product was heated in a constant temperature water bath at 40°C for 60 minutes and then transferred to a constant temperature water bath at 90°C for 30 minutes to obtain the surimi gel. The gel strength of the sample in Example 3 during the freeze-thaw process and the rheological properties of the surimi during different oscillation frequencies were measured to evaluate the gel stability and viscoelasticity of the sample. Figure 3 .

[0050] Comparative Example 1

[0051] First, the pomfret is scaled, boned, deboned, and skinned, and then cut into small pieces and placed in a meat grinder for 1 minute to grind it; 500g of the minced fish meat is placed in 5L of ordinary alkaline electrolyzed water (pH 9.50) and soaked for 5 minutes. The water activity value of the surimi slurry after rinsing and filtering the water is measured by a water activity meter at 60%, and 500mL of ice water is added to control the water content of the fish meat to maintain at 80%. Add 1.5% salt of the mass of the pomfret and continue to chop and stir for 5 minutes to obtain a surimi slurry product. Add 2.5u / g MTGase to the obtained raw pulp product, chop and stir for 2 minutes, and then shape it. The shaped raw pulp product is heated in a constant temperature water bath at 40℃ for 30 minutes and then transferred to a constant temperature water bath at 88℃ and heated for 60 minutes to obtain a surimi gel. The samples in Comparative Example 1 were taken to measure the gel strength, flavor components and rheological properties during the freeze-thaw process to evaluate the changes in the gel properties, stability and volatile substances of the surimi.

[0052] Comparative Example 2

[0053] The pomfret was scaled, boned, deboned and skinned, cut into small pieces, and placed in a meat grinder for 2.5 minutes to grind it; 500g of the minced fish meat was placed in a purified water tank (food safety food purification tank) with 10L of tap water for electrolysis for 5 minutes, the output power of the electrolysis process was 480W, and the pH value of the prepared electrolyzed water was 8.64. The water activity value of the surimi slurry after rinsing and filtering the water was measured by a water activity meter at 60%, and 500mL of ice water was added on this basis to control the water content of the fish meat to maintain at 80%. 2.5% salt of the mass of the pomfret was added and continued to be chopped for 3 minutes to obtain a surimi slurry product. The shaped raw slurry product was heated in a constant temperature water bath at 40°C for 60 minutes and then transferred to a constant temperature water bath at 90°C for heating for 30 minutes to obtain a surimi gel. The samples in Comparative Example 2 were taken to measure the gel strength, flavor components and rheological properties during the freeze-thaw process to evaluate the gel properties, stability and changes in volatile substances of the samples.

[0054] Comparative Example 3

[0055] After descaling, debone, deboning and skinning the pomfret, cut it into small pieces and place it in a meat grinder for 5 minutes to grind it; 500g of the minced fish meat was placed in a 5L ice water bath and soaked for 5 minutes. The water activity value of the fish paste after rinsing and filtering the water was measured by a water activity meter at 60%, and 500mL of ice water was added on this basis to control the water content of the fish meat to be maintained at 80%. Add 1.5% salt of the mass of the pomfret and continue to chop and stir for 5 minutes to obtain a fish paste raw pulp product. Add 2.5u / g MTGase to the obtained raw pulp product, chop and stir for 2 minutes, and then shape it. The shaped raw pulp product was heated in a constant temperature water bath at 40°C for 45 minutes and then transferred to a constant temperature water bath at 90°C for 45 minutes to obtain a fish paste gel. The sample in Comparative Example 3 was taken to measure the gel strength, flavor components and rheological properties during the freeze-thaw process to evaluate the changes in the fish paste gel properties, stability and volatile substances.

[0056] In the above comparative examples, Comparative Example 1 is treated with ordinary alkaline electrolyzed water and then MTGase is added, Comparative Example 2 is simply treated with alkaline water of the purification tank of the present invention; Comparative Example 3 is treated with MTGase after soaking in ice water; and the embodiment uses alkaline water of the purification tank combined with MTGase for treatment. Specifically, Comparative Example 1 uses ordinary alkaline electrolyzed water with saturated potassium chloride solution as electrolyte, ionizes tap water through the Xinkangfu hydrogen electrolyzer, and prepares alkaline electrolyzed water with a pH of 12 at the anode to soak the fish meat. The alkaline electrolyzed water prepared by the Baoshian food purification tank used in the embodiment of the present invention does not require the addition of other electrolyte materials, and the raw materials to be treated are added to the electrolytic cell before power is turned on, while the ordinary alkaline electrolyzed water treatment is soaked after electrolysis. The pH value of the alkaline water generated by the material of the present invention during the electrolysis process is weaker than that of the ordinary alkaline electrolyzed water obtained by electrolysis with saturated potassium chloride solution. The electrolysis process of the embodiment is also affected by the electric waves generated by the electric energy and the light.

[0057] Rheology describes the flow characteristics and mechanical properties of surimi, reflects the changes in the internal structure of the raw material, and is used to characterize the changes in the molecular morphology and properties of surimi during heating to predict the quality of surimi. Figure 1 It can be seen that within the temperature scanning range of 20 to 90°C, the formation of a gel network during the transition from sol to gel of the surimi samples in Example 1 and Comparative Example 1, Comparative Example 2 and Comparative Example 3. During the dissociation process of the myosin double helix structure at 20 to 35°C, the storage modulus G' of Example 1 is the highest, followed by the G' of Comparative Example 2, indicating that Example 1 has higher stability at this stage, and more energy is required to destroy its structure as the temperature increases. In the 35 to 45°C stage, Example 1 still exhibits a relatively high G', indicating that the interaction between protein molecules is tighter after the combined treatment of alkaline water and MTGase, forming more protein aggregates. At this stage, Comparative Examples 1, Comparative Examples 2 and Comparative Examples 3 exhibit lower G'. The temperature range of 60 to 75°C is generally considered to be the gel strengthening stage. Example 1 maintains the best viscoelasticity when forming a gel, followed by the sample of Comparative Example 3. Comparative Example 1 exhibits a relatively low G', which further illustrates that when alkaline electrolyzed water and MTGase are co-treated, the number of cross-links between protein molecules is large and the surimi gel performance is good. According to Figure 3 The change in storage modulus of the surimi in the frequency range of 1-100 Hz also shows that G' of Example 1 exhibits relatively stable viscoelasticity in the entire frequency scanning range, which is significantly greater than that of Comparative Examples 1, 2 and 3.

[0058] Rinsing fish paste is a common method for removing fishy smell. Sensory masking methods are often used at home and abroad, that is, adding spices and using microbial fermentation to improve the smell. However, these methods affect the gel properties of fish paste or introduce other flavor substances to varying degrees. Chemical methods for removing fishy smell are also widely used in production practice, including acid, alkali and salt treatment. Acid, alkali and salt solutions are difficult to completely remove after use and have significant residual problems. Figure 2 The changes of volatile components of fish paste by each treatment were measured by GC-MS in Example 2 of the present invention and Comparative Examples 1, 2, and 3. 33 volatile substances including chloroform, n-butanol, hexanal, 4-methyloctane, heptaldehyde, 1-octen-3-ol, octamethylcyclotetrasiloxane, decane, n-octanal, 1,2,3,4-tetramethylbenzene, 1,2,3,5-tetramethylbenzene, naphthalene, dodecane, n-tridecane, dodecamethylcyclohexasiloxane, tetradecane, 1-caryophyllene, hexadecane, and heptadecane were screened out by qualitative analysis. Figure 2 It can be found from the normalized heat map that the volatile substances such as n-tridecane, n-butanol, tetradecane and 1-caryophyllene in the fish paste after treatment in Example 2 are reduced most significantly. Secondly, compared with Comparative Examples 2 and 3, the volatile substances such as dodecane, trichloromethane, heptaldehyde, 4-methyloctane, dodecane, n-octanal and decane in Example 2 are significantly reduced. On the contrary, Figure 2 It can be found that the content of volatile substances such as hexadecane, heptadecane and 1-octen-3-ol in Comparative Example 2 is significantly reduced compared with Comparative Example 1, but the content of substances such as 1,2,3,4-tetramethylbenzene, 1,2,3,5-tetramethylbenzene, n-octanal, decane and dodecamethylcyclohexasiloxane is also increased accordingly, indicating that although alkaline water treatment can reduce certain fishy components in fish paste, it may also increase the accumulation of aldehyde and alkane volatile substances accordingly. However, Comparative Example 3 shows more volatile substances after treatment. The content of volatile substances affects the flavor of fish paste gel. The decrease in decane content is conducive to less fat in fish paste. The decane content in Example 2 is significantly lower than that in Comparative Example 2 and Comparative Example 3; in addition, the volatile substance of 1-octen-3-ol is rich in earthy smell, which is effectively improved in Comparative Examples 2, 3 and Example 2. Compared with Comparative Example 1, Example 2 is also significantly improved in the reduction of heptanal rich in fishy smell. It can be seen that Example 2 has obvious advantages in terms of the reduction of the entire volatile substances, especially compared with Comparative Example 2.

[0059] Gel strength is a key indicator for evaluating the quality of surimi, which affects the texture, yield and grade of commercial surimi. Table 1 tests the changes in the gel strength of surimi gels in Comparative Examples 1, 2, 3 and Example 3 in different freeze-thaw cycles by texture analyzer. The initial gel strength of the surimi gel after treatment with ordinary alkaline electrolyzed water (Comparative Example 1) is 337.89±33.12g*mm, and the gel strength of the surimi gel treated with only MTGase (Comparative Example 3) is increased by 10.70% compared with Comparative Example 1, indicating that the addition of MTGase can increase the cross-linking degree of the gel to a certain extent and improve the quality characteristics of the surimi gel. Similarly, after the surimi is treated with alkaline electrolyzed water (Comparative Example 2) prepared by the food safety food purification tank of the present invention, its initial gel strength is increased by 27.72% compared with Comparative Example 1, which is also higher than the gel strength of the surimi gel after treatment in Comparative Example 3. The initial surimi gel strength after treatment in Example 3 is increased by 31.27% compared with Comparative Example 1, and the increase is significantly higher than that in Comparative Example 2 and Comparative Example 3. It can be seen that the alkaline water and MTGase co-treatment used in the present invention exhibits significantly superior fish paste gel properties.

[0060] The freeze-thaw cycle test is to freeze the surimi after different treatments in a -20°C refrigerator for 72 hours and then thaw it in a 4°C refrigerator for 24 hours to obtain a freeze-thaw cycle sample. It can be found from Table 1 that with the increase in the number of freeze-thaw cycles, the gel strength of each group of surimi gradually decreases, and during the entire freeze-thaw cycle, the gel strength value of the surimi of Example 2 decreases more slowly. At the first freeze-thaw, the gel strength of the surimi of Comparative Example 1 was 315.39±9.08g*mm, which was significantly reduced by 22.5±24.04g*mm compared with the initial surimi gel strength. During this period, the gel strength of the surimi in Comparative Example 2 and Comparative Example 3 increased by 29.08% and 6.18% compared with Comparative Example 1. However, the gel strength of the surimi in Example 2 increased by 34.95% compared with Comparative Example 1, indicating that Example 2 showed higher gel strength after one freeze-thaw cycle compared with Comparative Example 1, Comparative Example 2 and Comparative Example 3. When the number of freeze-thaw cycles was increased to 4, the gel strength of the surimi of Example 2 was still significantly higher than that of the control groups. Therefore, the gel strength of the surimi can be significantly improved by combining alkaline electrolyzed water treatment with MTGase treatment.

[0061] Table 1 Changes in gel strength of surimi raw materials during freeze-thaw process under different treatment conditions

[0062]

[0063] In Table 1, under the same freeze-thaw times, different lowercase letters in different embodiments indicate significant differences between the samples (p<0.05).

[0064] In summary, the present invention utilizes alkaline water from a purified water tank in coordination with transglutaminase to treat surimi, which has obvious advantages in terms of viscoelasticity, volatile components, and freeze-thaw performance tests compared with ordinary alkaline water combined with transglutaminase to treat surimi, or alkaline water from a purified water tank alone to treat surimi, and better maintains the gel strength of the surimi during frozen storage.

[0065] It should be noted that the embodiments of the present invention do not limit the protection scope of the present invention. Any other different forms of changes or modifications made using the contents of the present invention specification, or direct or indirect applications in other related technical fields are also included in the protection scope of the present invention.

Claims

1. A method for enhancing the gel properties and stability of surimi by alkaline electrolyzed water, characterized in that The steps include: Step 1: pre-treat the fish, cut it into pieces, and mince it to obtain minced fish meat; Step 2: Place the minced fish meat in a purified water tank and electrolyze and rinse for 1-9 minutes; control the water in the purified water tank to be alkaline water with a pH value of 7.50-9.30; Step 3: Control the moisture content of the minced fish meat after the electrolytic rinsing in step 2 to be 78±5%, thereby obtaining minced fish; Step 4: Add salt to the minced fish, chop and mix to obtain raw minced fish; Step 5, adding glutamine aminotransferase to the raw fish paste, chopping and mixing, and obtaining raw fish paste; Step 6: shaping the surimi slurry in a mold and then heating it to obtain surimi gel.

2. The method for enhancing the gel properties and stability of surimi by alkaline electrolyzed water according to claim 1, characterized in that: The pretreatment is to remove scales, bones, skin and bones of the fish to obtain the white meat part as the raw material for producing minced fish.

3. The method for enhancing the gel properties and stability of surimi by alkaline electrolyzed water according to claim 1, characterized in that: The mincing is carried out in a meat grinder at a speed of 2000-5000 r / min for 1-5 min.

4. The method for enhancing the gel properties and stability of surimi by alkaline electrolyzed water according to claim 1, characterized in that: The output power of the purified water tank is 380-550W; the water in the purified water tank is tap water.

5. The method for enhancing the gel properties and stability of surimi by alkaline electrolyzed water according to claim 1, characterized in that: In the control step 2, the water content in the minced fish meat after electrolytic rinsing is controlled by measuring the water content in the minced fish meat after electrolytic rinsing with a water activity meter and then adding ice water.

6. The method for enhancing the gel properties and stability of surimi by alkaline electrolyzed water according to claim 1, characterized in that: The amount of salt added is 1.0-2.5% of the mass of the fish in step one.

7. The method for enhancing the gel properties and stability of surimi by alkaline electrolyzed water according to claim 1, characterized in that The added amount of the glutamine transaminase is 1-5u / g.

8. The method for enhancing the gel properties and stability of surimi by alkaline electrolyzed water according to claim 1, characterized in that: The chopping time described in step 4 and step 5 is 1-5 minutes.

9. The method for enhancing the gel properties and stability of surimi by alkaline electrolyzed water according to claim 1, characterized in that: During the heating, the mixture is first placed in a constant temperature water bath at 40-45° C. and heated for 30-60 minutes, and then transferred to a constant temperature water bath at 85-90° C. and heated for 30-60 minutes.

10. The method for enhancing the gel properties and stability of surimi by alkaline electrolyzed water according to claim 1, characterized in that: The fish paste gel with gel properties and stability is used for making fish cakes, fish sticks, fish balls or fish cakes.

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