Unfreezing method for improving quality of skipjack meat

Abstract

The invention provides an unfreezing method for optimizing the quality of skipjack meat, and belongs to the technical field of marine fish unfreezing. According to the method, conditions for unfreezing skipjack meat through hydrogen micro-nano bubble water and radio frequency are optimized by combining a single factor with an orthogonal experiment, so that an optimal unfreezing process is expected to be obtained. The soaking time, the material-liquid ratio and the hydrogen micro-nano bubble water concentration are used as single factors, the TBARS is used as a response value, and the obtained optimal unfreezing conditions are that the soaking time is 12 min, the material-liquid ratio is 1: 6, and the hydrogen micro-nano bubble water concentration is 40%. Compared with other unfreezing methods, the novel unfreezing method has the advantages that the unfreezing time is shortened, and the fish body has good water-retaining property; and oxidation of fish meat fat is inhibited in the thawing process.

Description

Technical Field

[0001] The invention relates to the technical field of marine fish thawing, and in particular to a process for thawing bonito by utilizing hydrogen micro-nano bubble water combined with radio frequency. Background Art

[0002] Seafood such as skipjack tuna is one of the important economic fish in my country's marine fisheries, and its output accounts for more than 70% of the total tuna catch. Skipjack tuna is a tuna with high economic benefits and is one of the most important target fish species in the tuna fishery in the Central and Western Pacific. At the same time, skipjack tuna is a low-value tuna. Because of its high proportion of dark meat, strong fishy smell and poor taste, it has not been well developed and utilized. However, its catch volume is large and its price is cheap, so it has great market potential and is often used as canned tuna. Skipjack tuna is immediately frozen, stored and distributed after being caught, and then thawed before processing. Traditional thawing methods such as air thawing and static water thawing are time-consuming and cause serious nutrient loss. Fish meat is rich in protein. The long thawing process will cause the fish meat to oxidize under the action of enzymes or microorganisms, causing the fish meat to spoil.

[0003] At present, the commonly used fish thawing methods include single thawing technologies such as air, low temperature, water bath, ultrasound, microwave, magnetic field or electrostatic field. Air thawing has low cost, but has problems such as poor thermal conductivity and slow thawing speed; water thawing takes less time than air thawing, but long-term immersion in water can easily cause microbial contamination and reproduction, and may also cause quality deterioration problems such as juice loss, lipid oxidation, and myofibrillar protein denaturation. Therefore, it is of great significance to develop a new fish thawing process to improve the degree of deterioration of fish protein and lipids during the thawing process, improve the microbial safety of thawed meat, and extend the shelf life of the product. Summary of the invention

[0004] In view of the above problems, the present invention provides a thawing method for improving the quality of bonito meat.

[0005] On the one hand, the present invention provides a thawing method for optimizing the quality of bonito meat, wherein the bonito is placed in hydrogen micro-nano bubble water for soaking, and then placed in a thawing furnace for thawing to 4±1°C.

[0006] In some embodiments, the concentration of the hydrogen micro-nano bubble water is 40%.

[0007] In some embodiments, the solid-liquid ratio of the bonito to the hydrogen micro-nano bubble water is 1:6.

[0008] In some embodiments, the soaking time is 12 minutes.

[0009] In some embodiments, the thawing frequency of the radio frequency thawing furnace is 40.68 MHZ.

[0010] In another aspect, the present invention provides a thawing method for optimizing the quality of bonito meat and its application in bonito food processing.

[0011] Compared with the prior art, the present invention has the following advantages:

[0012] (1) The thawing method of the present invention can reduce the loss of juice caused by thawing, thereby allowing the bonito to maintain good elasticity and chewiness.

[0013] (2) The present invention measured the TBARS of thawed fish meat. Compared with the thawing method of radio frequency alone, the TBARS value of hydrogen micro-nano bubble water combined with radio frequency thawing was reduced by 0.621 mg / 100 g.

[0014] (3) The thawing method of the present invention uses hydrogen micro-nano bubble water combined with radio frequency thawing. Hydrogen can inhibit lipid peroxidation and further reduce the impact of thawing on the quality of bonito.

[0015] In the present invention, the hydrogen micro-nano bubble water having a hydrogen content of 12800 ppb is set to a concentration of 100%, and is diluted with deionized water to obtain a desired concentration. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The effect of hydrogen micro-nano bubble water with different immersion times on TBARS of thawed fish meat.

[0017] Figure 2 The effect of different feed-liquid ratios on TBARS of fish meat.

[0018] Figure 3 The effect of different concentrations of hydrogen micro-nano bubble water on TBARS of fish meat.

[0019] Figure 4 This is the thawing loss rate of bonito after thawing in four different ways.

[0020] Figure 5 This is the centrifugal loss rate of bonito after thawing in four different ways.

[0021] Figure 6 Effects of different thawing methods on pH of fish meat.

[0022] Figure 7 The TBARS content test chart of bonito after thawing in four groups using different thawing methods.

[0023] Figure 8 The microscopic structure of bonito after thawing in four different ways. DETAILED DESCRIPTION

[0024] The technical scheme in the embodiment of the present invention is clearly and completely described below. Obviously, the described embodiment is only a part of the embodiment of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. The reagents involved in the embodiments of the present invention are purchased from commercial channels, and the methods not mentioned are conventional experimental methods, which are not described one by one here.

[0025] Example 1

[0026] This embodiment provides a process for optimizing the thawing of bonito fish chunks, the steps of which are as follows:

[0027] 1. Single factor experiment: Three factors, namely, soaking time, material-liquid ratio, and hydrogen micro-nano bubble water concentration, were selected to determine the TBARS value of bonito meat.

[0028] (1) The TBARS value of bonito meat was determined by fixing the material-liquid ratio at 1:2 g / mL and the concentration at 100% and changing the soaking time to 3, 6, 9, 12, 15, and 18 min. The experimental results are shown in the attached figure. Figure 1 as shown in .

[0029] (2) The TBARS value of bonito meat was determined by fixing the soaking time at 3 min and the concentration at 100% and changing the material-liquid ratio to 1:3, 1:4, 1:5, 1:6, and 1:7 g / mL. The experimental results are shown in the attached figure. Figure 2 shown.

[0030] (3) The TBARS value of bonito meat was determined by fixing the material-liquid ratio at 1:2 g / mL and the soaking time at 3 min, changing the concentration to 40, 50, 60, 70, and 80%. The experimental results are shown in the attached figure. Figure 3 shown.

[0031] 2. Orthogonal experiment: Based on the single-factor experiment, an orthogonal experiment with three factors and three levels is established. The factor level table is shown in Table 1.

[0032] Purchase HiHydrogen drinking water (specification 360mL, hydrogen content 12800ppb) from Hubei HiHydrogen Health Technology Co., Ltd., set its concentration to 100%, dilute it with deionized water, and prepare 40%, 50%, and 60% hydrogen micro-nano bubble water respectively.

[0033] Table 1 Orthogonal experimental factor level table

[0034]

[0035] A total of 9 groups of experiments were responded, with A soaking time (min), B material-liquid ratio (g / mL), C concentration (%) as independent variables, and fish meat TBARS value as the investigation index. The design combinations and their corresponding experimental results are shown in Table 2.

[0036] Table 2 Orthogonal design and experimental results

[0037]

[0038]

[0039] Table 3 Orthogonal experiment variance results

[0040] Sources of variance Type III Sum of Squares Degrees of Freedom Mean Square F Significance Modified Model <![CDATA[23.245 a ]]> 6 3.874 2.943 0.032 intercept 1140.555 1 1140.555 866.281 0.000 A 2.439 2 1.219 0.926 0.412 B 10.902 2 5.451 4.140 0.031 C 9.904 2 4.952 3.761 0.041 error 26.332 20 1.317 total 1190.132 27 Corrected Total 49.577 26

[0041] As shown in Table 2, the order of influence of the factors on the TBARS value of bonito meat is: material-liquid ratio (B) > concentration (C) > soaking time (A). The optimal combination condition is A3B2C1, that is, soaking time 18min, material-liquid ratio 1:6g / mL, concentration 40%.

[0042] As shown in Table 3, the material-liquid ratio and concentration have significant effects on the TBARS value of bonito meat (P<0.05), while the effect of soaking time is not significant, and the optimal combination is selected as A1B2C1. According to the F value, the primary and secondary relationships of the three single factors on the TBARS value of bonito meat are consistent with the results of the range analysis.

[0043] 30±5g of frozen bonito chunks were taken out from a -24℃ refrigerator and placed in a polyethylene bag filled with 40% hydrogen micro-nano bubble water at a material-liquid ratio of 1g:6mL. After soaking for 12 minutes, they were placed in a 40.68MHZ radio frequency thawing furnace. The study found that lower output power can make the temperature distribution more uniform, which helps to improve the thawing uniformity. The fish chunks were thawed until the center temperature was 4±1℃.

[0044] Comparative Example 1

[0045] Take out the frozen bonito fish block of the same mass as that in Example 1 from the -24°C refrigerator, and put it into a polyethylene bag filled with 40% hydrogen micro-nano bubble water at a material-liquid ratio of 1g:6mL to completely immerse it. Use a high-precision thermometer to measure the temperature of the center of the fish block every 3 minutes, and when the center of the fish body reaches 4±1°C, thawing is completed.

[0046] Comparative Example 2

[0047] Take out the frozen bonito fish pieces of the same mass as that in Example 1 from the -24°C refrigerator, and place them in a polyethylene bag filled with deionized water at a material-liquid ratio of 1 g:6 mL to completely immerse them. The bonito fish in the deionized water is immediately placed in a 40.68 MHZ radio frequency device for thawing, and the temperature of the center of the fish piece is measured every 3 minutes using a high-precision thermometer. When the center of the fish body reaches 4±1°C, the thawing is completed.

[0048] Comparative Example 3

[0049] Take out the frozen bonito fish block of the same mass as that in Example 1 from the -24°C refrigerator, and place it in a polyethylene bag filled with deionized water at a material-liquid ratio of 1 g:6 mL to completely immerse it. Use a thermometer to measure the temperature of the center of the fish block every 3 minutes. When the temperature of the center of the fish meat reaches 4±1°C, thawing is complete.

[0050] Example 4

[0051] The different thawing treatments of Example 1 and Comparative Examples 1-3 were recorded as HBW-RF group, HBW group, RF group, and DW group, and the following research was conducted:

[0052] 1. Effect of different thawing treatments on thawing loss rate

[0053] The loss and stability of water in the sample during and after thawing can be evaluated by measuring the thawing loss rate. Accurately weigh the mass of the fish pieces before and after the thawing treatments of the above four groups. After thawing, use absorbent paper to absorb the water on the surface of the bonito meat, then measure its mass, and calculate the thawing loss rate of the bonito meat according to the formula.

[0054] Water holding capacity is an indicator for evaluating the quality of fish meat after thawing, and is also an indicator for measuring the tightness and integrity of muscle fibers. Figure 4 As shown, the thawing loss rates of the four treatment groups were significantly different (P<0.05), and the centrifugal loss rates of the RF, HBW-RF, HBW, and DW groups were 4.389%, 3.015%, 1.156%, and 4.269%, respectively. It can be seen that the loss rate of the HBW-RF group was lower than that of the RF group, indicating that the thawing method of the present invention has a positive synergistic effect between the hydrogen micro-nano bubble water and the electromagnetic field generated by the radio frequency, and can improve the water loss caused by radio frequency thawing.

[0055] 2. Effect of different thawing treatments on centrifugal loss rate

[0056] Centrifugal loss rate is an indicator for evaluating the quality of meat after thawing, and is also an indicator for measuring the tightness and integrity of muscle fibers. Weigh 1g of bonito meat in a centrifuge tube. Centrifuge at 4°C, 4000×g for 30 minutes. Wipe dry with filter paper and weigh the mass.

[0057] Water holding capacity is an indicator for evaluating the quality of fish meat after thawing, and is also an indicator for measuring the tightness and integrity of muscle fibers. As shown in the figure, the thawing loss rates of the four treatment groups were significantly different (P<0.05), and the centrifugal loss rates of the RF, HBW-RF, HBW, and DW groups were 25.796%, 18.124%, 26.278%, and 33.298%, respectively. It can be seen that the loss rate of the HBW-RF group is lower than that of the RF group, indicating that the thawing method of the present invention has a positive synergistic effect between the hydrogen micro-nano bubble water and the electromagnetic field generated by the radio frequency, which can improve the water loss caused by radio frequency thawing.

[0058] 3. Effect of different thawing treatments on texture

[0059] Texture characteristics are one of the important indicators for evaluating fish quality, which is related to the destruction of muscle tissue and the oxidation of protein and lipid. The hardness, elasticity, chewiness and cohesion of the above four groups of fish pieces with different thawing treatments were tested, and the results are shown in Table 4.

[0060] In terms of hardness, the HBW-RF and DW groups had the highest hardness values ​​(1096.4±93.004g, 1305.2±327.786g), followed by the RF and HBW groups (605±73.654g, 532.2±52.883g), reflecting that the combination of hydrogen micro-nano bubble water and radio frequency can effectively improve the hardness of fish meat. Similarly, the elasticity value of HBW-RF (4.134±0.63) was higher than that of HBW (3.166±0.293mm) and RF (2.76±0.26mm) groups, respectively. In terms of adhesion, chewiness, and cohesion, HBW-RF also had the highest value. Overall, the treatment of the HBW-RF group effectively improved the hardness, elasticity, chewiness, adhesion, and cohesion of fish meat.

[0061] Table 4 Effects of four different thawing methods on the texture characteristics of bonito

[0062]

[0063] Different lowercase letters indicate P < 0.05

[0064] 4. Effect of different thawing treatments on color difference

[0065] Color difference is one of the important indicators for evaluating fish quality, which is related to the destruction of muscle tissue and the oxidation of protein and lipid. Generally speaking, the L* value represents the brightness of the meat sample. The larger the value, the better the glossiness of the meat; the a* value represents the redness. The higher the value, the better the color and fresher the meat; the b* value represents the yellowness. The higher the value, the less fresh the meat.

[0066] As shown in Figure 5, the a* and L* of HBW-RF were significantly lower than those of the other groups; the b* value is considered to be closely related to the degree of lipid oxidation in meat, and the increase in the b* value represents an increase in the degree of lipid oxidation to a certain extent. Therefore, the HBW-RF group significantly reduced the degree of lipid oxidation in thawed fish meat.

[0067] Table 54 Effects of different thawing methods on color difference of bonito

[0068]

[0069] 5. Effect of different thawing treatments on pH

[0070] pH is one of the important indicators for evaluating fish quality, which is related to the destruction of muscle tissue and the oxidation of protein and lipid. During the thawing process of tuna, protein denaturation causes pH + The pH value of fresh tuna meat is generally maintained at 7.0-7.3. With the loss of water during the thawing process, + The concentration gradually increases, such as Figure 6 As shown in the figure, the pH value of tuna meat decreased in all four thawing methods, and the pH value (5.143) of HBW-RF was the lowest. It can be seen that the thawing of HBW-RF combination was better than the other three groups.

[0071] 6. Effects of different thawing treatments on TBARS content

[0072] During the thawing process, polyunsaturated fatty acids in fish meat degrade to form malondialdehyde, which can be used to detect the degree of lipid oxidation and freshness of meat. Take the same mass (10g) of the fish blocks from the above four groups of different thawing treatments, homogenize with the trichloroacetic acid mixture, shake for 30 minutes, filter, take the supernatant and add TCA solution, bathe at 100℃ for 30 minutes, cool to room temperature, add chloroform, shake and stand for stratification, and use a UV spectrophotometer to measure the reaction solution of the treatment group samples at A. 532 , A 600 The absorbance at nm was used to calculate the thiobarbituric acid value (TBARS). The results are shown in the attached Figure 7 .

[0073]

[0074] Depend on Figure 7 It can be seen that the TBARS value of the DW group (5.663 mg / 100 g) was the highest, which was higher than that of the other three treatment groups, with significant differences (P<0.05). The RF and RF-HBW groups were followed, and the HBW group had the lowest TBARS value, indicating that HBW significantly inhibited the lipid oxidation of bonito during the thawing process, maintained the quality of bonito to the greatest extent, and improved the lipid oxidation caused by overheating during the thawing process of the RF group.

[0075] 7. Effects of different thawing treatments on microstructure

[0076] The same volume of samples were taken from the four groups of fish blocks with different thawing treatments, and the cross-sectional structures of the bonito meat were photographed by scanning electron microscope. The results are shown in Figure 8 .

[0077] Figure 8 It can be seen that the integrity of the muscle fiber bundles in the DW group was severely damaged. Although the muscle fiber structure of the HBW group was relatively regular, the muscle surface was uneven and there were more gaps. The muscle fiber structure of the RF group showed that there were many unevenly distributed muscle fibers. Compared with the RF and HBW groups, the surface of the HBW-RF group had less muscle fiber accumulation, a flatter tissue structure, and smoother, without any gap overlap. This shows that the combination of hydrogen micro-nano bubble water and radio frequency treatment can effectively alleviate the destruction of myofilament crystals caused by myofilament aggregation during thawing, and minimize the damage to muscle tissue.

[0078] Finally, it should be noted that the above examples are only some specific embodiments of the present invention. Obviously, the present invention is not limited to the above examples, and there are many variations. All variations that can be directly derived or associated with the content disclosed by a person skilled in the art should be considered as the protection scope of the present invention.

Claims

1. A thawing method for optimizing the quality of bonito meat, characterized in that: The bonito is placed in hydrogen micro-nano bubble water for soaking, and then placed in a thawing furnace for thawing to 4±1°C.

2. A thawing method for optimizing the quality of bonito meat according to claim 1, characterized in that: The concentration of the hydrogen micro-nano bubble water is 40%.

3. A thawing method for optimizing the quality of bonito meat according to claim 1, characterized in that: The material-liquid ratio of the bonito to the hydrogen micro-nano bubble water is 1:

6.

4. The thawing method for optimizing the quality of bonito meat according to claim 1, characterized in that: The soaking time is 12 minutes.

5. The thawing method for optimizing the quality of bonito meat according to claim 1, characterized in that: The thawing frequency of the radio frequency thawing furnace is 40.68MHZ.

6. Use of the thawing method for optimizing the quality of bonito meat according to any one of claims 1 to 5 in bonito food processing.

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