Fish meat aquatic product and processing method thereof

Abstract

The invention discloses a fish meat aquatic product and a processing method thereof, and the fish meat aquatic product is characterized in that after fish meat is processed, the mass content of alpha-helix of collagen in the fish meat is 20%-24%, the mass content of beta-corner of the collagen in the fish meat is 21%-25%, and the beta-folding content of the collagen in the fish meat is 40%-42%. The mass content of irregular curls of collagen in the fish meat is 10%-14%. According to the processing method, the meat quality of the fish meat is tender, and the processed fish meat has fresh and sweet taste after being cooked thoroughly.

Description

Technical Field

[0001] The present invention relates to the technical field of aquatic product processing, and in particular to a fish meat aquatic product and a processing method thereof. Background Art

[0002] Generally speaking, if a certain fish species, whether wild or farmed, contains a high amount of fat in its muscle tissue, its meat will feel particularly tender and sweet when people eat and swallow it. For example, in wild fish species, the bluefin tuna (three species, scientific names: Thunnus thynnus; T. orientalis; T. maccoyii), which belongs to the same family of scombridae, has an average muscle fat content of more than 15% (up to 40% in the abdomen), while the yellowfin tuna (scientific name: Thunnus albacares), a closely related species, has an average muscle fat content of less than 3%, and the skipjack tuna (scientific name: Katsuwonus pelamis), which has a larger population, has an average muscle fat content of only 1%, which makes the price per unit of bluefin tuna thousands of times higher than that of skipjack tuna. Oil content or fat content is generally expressed as a percentage by mass.

[0003] In the aquaculture industry, in order to allow farmed fish to accumulate fat, higher levels of protein and crude fat must be added to the feed, which will significantly increase the cost of the feed. During the feeding process, the incompletely ingested feed residues of high-protein and crude fat feed are more likely to decompose and affect the water quality. Even in open water farming such as offshore cages, it will also have an acidification effect on nearby waters.

[0004] In addition, in terms of the utilization of wild aquatic resources, fish in tropical waters grow faster than fish in temperate and frigid waters. Therefore, according to the advocacy of the Food and Agriculture Organization of the United Nations (FAO), fish resources in tropical areas have a short life cycle and are more in line with the ideal of sustainable utilization. However, fish in tropical waters often have a rough taste due to the low fat content in their muscles, which is commonly known as "woody". Summary of the invention

[0005] In view of this, in order to solve the above technical problems, the purpose of the present invention is to provide a fish meat aquatic product and a processing method thereof, which on the one hand can make the fish meat more tender, and on the other hand can make the processed fish meat taste fresh and sweet after being cooked.

[0006] The technical solutions adopted are:

[0007] The fish meat aquatic product of the present invention has a mass content of α-helix of collagen in the fish meat of 20%-24%, a mass content of β-turn of collagen in the fish meat of 21%-25%, a mass content of β-fold of collagen in the fish meat of 40%-42%, and a mass content of random curl of collagen in the fish meat of 10%-14%.

[0008] Furthermore, the mass content of α-helix of collagen in the fish meat is 22%-23%, the mass content of β-turn of collagen in the fish meat is 24%-25%, the mass content of β-fold of collagen in the fish meat is 40%-41%, and the mass content of random curl of collagen in the fish meat is 12%-13%.

[0009] Furthermore, the mass content of α-helix of collagen in the fish meat is 22.95%, the mass content of β-turn of collagen in the fish meat is 24.35%, the mass content of β-fold of collagen in the fish meat is 40.52%, and the mass content of random curl of collagen in the fish meat is 12.17%.

[0010] A method for processing fish meat and aquatic products of the present invention comprises the following steps: S1. placing the fish meat in water, and gradually heating the water temperature from room temperature to a temperature of 39-41° C. within 3-4 hours.

[0011] Further, in S1, the fish meat is put into a vacuum bag, water that can immerse the fish meat is put into the vacuum bag, and then the vacuum bag is squeezed to remove air and sealed; then the sealed vacuum bag is placed in a container with water, and the container is heated outside to gradually heat the water temperature from room temperature to a temperature of 39-41° C. within 3-4 hours. This heating method of putting the vacuum bag into a container can further ensure that the temperature rises very slowly.

[0012] Further, in S1, a temperature sensor is installed in the container for monitoring the water temperature. In this way, the water temperature can be gradually heated from room temperature to a temperature of 39-41° C. within 3-4 hours.

[0013] Furthermore, the method further comprises S2. taking out the fish meat, cooling it, and then freezing it for storage.

[0014] Furthermore, it also includes S3. performing secondary heating and cooking to achieve an edible state.

[0015] Furthermore, the secondary heating cooking is steaming or baking in an oven.

[0016] Furthermore, the fish meat is low-fat fish meat.

[0017] The beneficial effects of the present invention are:

[0018] After the fish meat is processed, the mass content of the α-helix of the collagen in the fish meat is 20%-24%, the mass content of the β-turn of the collagen in the fish meat is 21%-25%, the mass content of the β-fold of the collagen in the fish meat is 40%-42%, and the mass content of the irregular curl of the collagen in the fish meat is 10%-14%. At this time, after the fish meat is cooked and cooked for the second time, the fish meat with low fat content can also feel fresh and tender when chewing and eating.

[0019] In the processing method, the present invention achieves a specific content of α-helix, β-turn, β-fold and random coil of collagen in fish meat by slowly heating the fish meat from room temperature to a temperature of 39-41°C, for example, to 40°C within 3-4 hours. In this processing method, the process is carried out with very low entropy, and the temperature is gradually increased from room temperature to 40°C by very slow and uniform heat energy application over a period of 3-4 hours.

[0020] In the processing method, the present invention uses the dual conditions of lower heat energy and heat energy application time to perform a modification (denaturation) reaction on the α-helix, β-fold, etc. of collagen, so that the fish meat with a low fat content after the secondary processing of cooked fish meat can feel fresh and tender when chewing and eating.

[0021] The fish meat processed by the present invention still looks fresh in appearance, and can be stored, distributed and sold as frozen aquatic products. Consumers can eat the fish meat after secondary heating and cooking, and the cooking method is not limited to steaming or baking in an oven.

[0022] The fish meat processed by the present invention still looks fresh fish meat and can still be used as a commodity, such as raw fish fillet, raw fish steak, sashimi, etc. The storage, circulation and sale of the fresh fish meat are all handled in accordance with the standards for frozen aquatic products. Before eating, it needs to be thawed and cooked before eating, and the cooking method is not limited. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a graph showing the experimental results of the effects of different processing methods on the free hydroxyproline content in croaker meat. DETAILED DESCRIPTION

[0024] The present invention is described in detail below through specific examples, but the use and purpose of these exemplary embodiments are only used to illustrate the present invention, and do not constitute any form of limitation on the actual protection scope of the present invention, and do not limit the protection scope of the present invention to these.

[0025] Unless otherwise specified, the contents of protein secondary structures described below are all in mass percentage.

[0026] The experimental subjects used in the following Examples 1-3 and Comparative Examples 1-6 are all artificially cultured croaker (Black Croaker), whose Latin name is: Miichthy miiuy.

[0027] Example 1

[0028] A method for processing fish meat and aquatic products in this embodiment includes the following steps: putting the fish meat into a vacuum bag, filling the vacuum bag with water that can immerse the fish meat, specifically, putting in water that is 50±5% of the weight of the fish meat (approximately), then squeezing out the air from the vacuum bag and sealing it; then placing the sealed vacuum bag in a container with water, heating it outside the container, and gradually heating the water temperature from room temperature to 40°C within 3-4 hours.

[0029] Note that the bag containing the fish is suspended in the water of the container and does not touch the bottom of the container to avoid uneven temperature. A temperature sensor is installed in the container to monitor the water temperature and gradually heat it up to 40°C.

[0030] Example 2

[0031] Based on Example 1, the following steps are also included: S2. Take out the fish meat and place it for cooling, and then freeze it for storage.

[0032] Example 3

[0033] Based on Example 2, the following steps are also included: S3. Reheating and cooking are performed to achieve an edible state.

[0034] Comparative Example 1

[0035] The processing method of a fish aquatic product of the comparative example comprises the following steps: soaking the fish in water at 40° C. at a constant temperature for 4 hours.

[0036] Comparative Example 2

[0037] The processing method of a fish aquatic product of the comparative example comprises the following steps: soaking the fish in water at a constant temperature of 45° C. for 3 hours.

[0038] Comparative Example 3

[0039] The processing method of a fish meat aquatic product of the comparative example comprises the following steps: soaking the fish meat in water at a constant temperature of 45° C. for 1 hour.

[0040] Comparative Example 4

[0041] The processing method of a fish aquatic product of the comparative example comprises the following steps: soaking the fish in water at a constant temperature of 50° C. for 3 hours.

[0042] Comparative Example 5

[0043] The processing method of a fish aquatic product of the comparative example comprises the following steps: soaking the fish in water at a constant temperature of 50° C. for 1 hour.

[0044] Comparative Example 6

[0045] The processing method of a fish aquatic product in this comparative example comprises the following steps: placing the fish in water without using a vacuum bag for packaging, and then gradually heating the water temperature from room temperature to 40° C. within 1 hour.

[0046] Performance Test:

[0047] 1. Detection of secondary structure of croaker meat protein

[0048] The samples of croaker in Example 1 and Comparative Examples 1-6 were treated as follows: after vacuum freeze drying for 48 hours, they were crushed into 200-mesh powder, accurately weighed 2 mg, fully ground with KBr 1:100, pressed into tablets, and the air background spectrum was subtracted before each measurement. 32 scans were accumulated, and the resolution was 4 cm －1 Each sample was measured three times in parallel, and the most representative spectrum was used for analysis. Each sub-peak was confirmed by taking the second-order derivative and deconvolution of the amide I band of each sample, and the curve was fitted multiple times using Peakfit v4.12, and then the ratio of each secondary structure was calculated based on the peak area. The corresponding relationship between each sub-peak and the secondary structure is: 1600~1639cm －1 β-folding; 1640~1650cm －1 Random curl; 1651~1660cm －1 α-helix; 1661~1700cm －1 is the β-turn.

[0049] The experimental results are shown in Table 1.

[0050] Table 1 shows the effects of different processing methods on the secondary structure of croaker collagen

[0051]

[0052] 2. Detection of free hydroxyproline in croaker meat

[0053] After the fish samples of Example 1 and Comparative Example 1 were cooked through secondary heating, they were treated as follows: 100 g of the fish were added to 100 mL of distilled water in a ratio of 1:1, and the fish meat was fully crushed with a homogenizer (T18 homogenizer, Aika (Guangzhou) Instrument Equipment Co., Ltd.), and soaked for 30 minutes. The fish meat and the extract were placed in a centrifuge, centrifuged at 4000 g, 4 degrees, for 15 minutes, and the supernatant was taken. After measuring its volume, the supernatant was directly used for the determination of hydroxyproline content without digestion. The determination method was carried out according to the instructions of the hydroxyproline content detection kit (Beijing Solebow Technology Co., Ltd., item number: BC0255).

[0054] The experimental results can be found in Figure 1 shown.

[0055] The experimental results show that the use of Example 1 can increase the content of free hydroxyproline in fish meat and enhance the sweetness of fish meat.

[0056] 3. Detection of soluble collagen content in croaker meat

[0057] The croaker samples of Example 1 and Comparative Example 1 were treated as follows: 600 microliters of croaker boiled liquid were placed in an EP tube, 1400 microliters of extract (6 mol / L hydrochloric acid solution) were added, the tube cover was wrapped with a sealing film (to prevent the cover from bursting), and the tube was placed in a 110°C oven for 2-4 hours until the tissue was completely digested (no visible lumps). After cooling, about 1 mL of 10 mol / L NaOH solution was slowly added to adjust the pH to 6-8 (pH test paper or pH meter can be used for verification). Distilled water was added to make up to 4 mL and mixed. Centrifugation was performed at 16000 rpm and 25°C for 20 minutes, and the supernatant was taken for use (if the supernatant is still turbid, it can be filtered). Subsequently, an ELISA instrument was used to adjust the wavelength to 560 nm, and the hydroxyproline content was detected by a standard curve. The specific detection formula and the preparation of the standard solution were prepared with reference to the instructions of the hydroxyproline content detection kit (Beijing Solebold Technology Co., Ltd., item number: BC0255).

[0058] The experimental results are shown in Table 2.

[0059] Table 2. Effects of different processing methods on soluble collagen in croaker meat

[0060]

[0061] The experimental results show that the soluble collagen content of croaker meat can be significantly increased by using Example 1.

[0062] The soluble collagen content is a very important condition after denaturation. Generally speaking, soluble collagen is easily lost during the cooking process (into the soup, the water released from the ingredients during steaming, and if it is roasted, fried, it will be lost and charred). Therefore, under good denaturation conditions, soluble collagen will be retained in other protein fiber structures, which is one of the reasons for the tender taste.

[0063] 4. Detection of texture indexes of croaker meat

[0064] The croaker samples of Example 1 and Comparative Examples 1-6 were treated as follows: first cooled to 0-5°C for 2-3 hours, and then frozen at -18°C for more than 72 hours. After leaving the freezer, the samples were placed on a stainless steel island (simulating the restaurant kitchen processing environment) for thawing, and then cooked by secondary heating. After cooking, the texture index was tested with a texture analyzer. The texture analyzer used is as follows: TA.XTC-18 texture analyzer of Shanghai Baosheng Industrial Development Co., Ltd.

[0065] The experimental results are shown in Table 3.

[0066] Table 3. Effects of different processing methods on the texture of croaker meat

[0067]

[0068] The experimental results show that the use of Example 1 can improve the edible quality of the croaker meat, such as the texture, and the use of Example 1 can significantly reduce the texture indicators of the croaker meat, such as the hardness.

[0069] 5. Detection of secondary structure of croaker protein after secondary heating

[0070] The croaker samples of Example 1 and Comparative Examples 1-6 were treated as follows: secondary heating and cooking were performed to achieve an edible state, and then the secondary structure of the croaker meat protein was detected. The specific detection method refers to point 1: Detection of the secondary structure of croaker meat protein.

[0071] The experimental results are shown in Table 4.

[0072] Table 4. Effect of secondary heating on the secondary structure of collagen in croaker meat

[0073]

[0074]

[0075] Combined with Table 1 and Table 4, the experimental results show that, by using Example 1, the collagen in the fish meat of croaker can be put into a mild denaturation process. During the first treatment process, the collagen is in a stretched state. High temperature (secondary heating) causes the collagen fibers to denature and shrink violently, or even degrade, thereby increasing the soluble collagen content. After secondary heating, the collagen structure of the sample treated in Example 1 is more stretched, and the content of α-helix (collagen helical structure) is slightly reduced, transforming to a denatured state (β-turn, β-fold, irregular curl) (Table 1, Table 4). This stretched collagen structure also leads to partial collagen hydrolysis (increase in free hydroxyproline, see Figure 1 ), thereby improving the tenderness of the meat.

[0076] The experimental subjects used in Examples 1-3 and Comparative Examples 1-6 are all artificially cultured croaker (black croaker), which is a low-fat fish.

[0077] Wild black croaker is widely distributed in temperate and tropical waters. It has delicate meat and a fat content of 8% to 10%. It grows slowly and its maw is a high-end tonic called isinglass. Therefore, black croaker has been a high-priced aquatic fish in my country's coastal provinces since the Ming Dynasty.

[0078] Although black croaker has been artificially bred in recent years, the breeding cycle is more than three years, and the fish bladder is mainly used to process it into a tonic. Because the feed used is relatively cheap, the fat content of the fish meat is only between 1% and 2%, and its value is far lower than that of wild black croaker. The processing method of the present invention can effectively improve the edible value and economic value of the cultivated black croaker.

[0079] In addition, the experimental subjects of the present invention include but are not limited to another species: wild rooster scad, whose Latin name is Caranx ignobilis, has also been subjected to actual experimental tests and analyzed for significance using the T-test method. The results under the same test conditions are all significant at P<0.05.

[0080] The series of detailed descriptions listed above are only specific descriptions of feasible embodiments of the present invention. They are not intended to limit the scope of protection of the present invention. All equivalent embodiments or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A fish aquatic product, characterized in that: After the fish meat is processed, the mass content of alpha-helix of collagen in the fish meat is 20%-24%, the mass content of beta-turn of collagen in the fish meat is 21%-25%, the beta-fold content of collagen in the fish meat is 40%-42%, and the mass content of irregular curl of collagen in the fish meat is 10%-14%.

2. The fish and aquatic product according to claim 1, characterized in that: The mass content of α-helix of collagen in the fish meat is 22%-23%, the mass content of β-turn of collagen in the fish meat is 24%-25%, the mass content of β-fold of collagen in the fish meat is 40%-41%, and the mass content of random curl of collagen in the fish meat is 12%-13%.

3. The fish and aquatic product according to claim 2, characterized in that: The mass content of α-helix of collagen in the fish meat is 22.95%, the mass content of β-turn of collagen in the fish meat is 24.35%, the mass content of β-fold of collagen in the fish meat is 40.52%, and the mass content of random curl of collagen in the fish meat is 12.17%.

4. A method for processing fish and aquatic products according to any one of claims 1 to 3, characterized in that: The method comprises the following steps: S1. placing the fish meat in water, and gradually heating the water temperature from room temperature to a temperature between 39 and 41° C. within 3 to 4 hours.

5. The method for processing fish and aquatic products according to claim 4, characterized in that: In S1, the fish meat is put into a vacuum bag, water that can immerse the fish meat is put into the vacuum bag, and then air is squeezed out of the vacuum bag and the bag is sealed; then the sealed vacuum bag is placed in a container with water, and the container is heated outside to gradually heat the water temperature from room temperature to a temperature between 39 and 41° C. within 3 to 4 hours.

6. The method for processing fish and aquatic products according to claim 5, characterized in that: In S1, a temperature sensor is installed in the container to monitor the water temperature.

7. The method for processing fish and aquatic products according to claim 6, characterized in that: The process further includes S2. taking out the fish meat, cooling it, and then freezing it for storage.

8. The method for processing fish and aquatic products according to claim 7, characterized in that: The method further includes S3. performing secondary heating and cooking to achieve an edible state.

9. The method for processing fish and aquatic products according to claim 8, characterized in that: Secondary cooking is steaming or oven baking.

10. The method for processing fish and aquatic products according to claim 4, characterized in that: The fish meat is low-fat fish meat.

Images