A green and efficient method for improving the antifreeze water retention of pre-prepared conditioned crayfish

Abstract

The present invention relates to a green and efficient method for improving the antifreeze and water retention of pre-prepared conditioned crayfish, which belongs to the field of deep processing of agricultural products. Fresh crayfish are selected as raw materials, and after being cleaned and shelled, variable frequency ultrasonic assisted impregnation is performed. In the first stage, the crayfish is placed in a trehalose solution, the frequency is set to 45KHz, and the power density is 0.35-0.42W / cm 2 , temperature 20-25℃, time 5-8min; in the second stage, put it into alginate oligosaccharide solution, set the frequency to 20KHz, and the power density to 0.55-0.62W / cm 2 , temperature 20-25℃, time 6-8min; seasoning, cooking, cooling, quick freezing, packaging and then frozen storage. The method of the invention significantly reduces the loss rate of cooking and thawing of pre-prepared conditioned crayfish, and effectively maintains its texture characteristics.

Description

Technical Field

[0001] The invention relates to a green and efficient method for improving the antifreeze and water retention of prefabricated conditioned crayfish, and belongs to the field of deep processing of agricultural products. Background Art

[0002] Crayfish, scientifically known as Procambarus clarkii, is rich in nutrition and delicious. It is one of the best-selling freshwater shrimps in the Chinese market. With the rapid growth of crayfish consumption, the categories of crayfish processing are becoming more diversified and specialized. Many domestic companies have continuously developed pre-prepared and conditioned crayfish products such as thirteen spices, garlic paste, spicy, and braised in oil according to the preferences of consumers in different regions. They are deeply favored by consumers. Not only is the transaction volume of the products increasing day by day in the domestic e-commerce market, but they are also exported to South Korea, Japan, Singapore, Malaysia, Australia and other countries. However, pre-prepared conditioned crayfish products have a high water content and are rich in nutritious small molecules. They are extremely easy to spoil at room temperature, and their sales and consumption restrictions are often changed through freezing and preservation.

[0003] However, during the freezing and thawing process of aquatic products, the freezing of free water and the separation of protein-bound water will lead to juice loss in the product. At the same time, the separation of bound water will cause the protein to undergo freezing denaturation and ultimately affect the product quality. How to improve the water retention of aquatic products and prevent the freezing denaturation of proteins has always been a hot topic in the research of aquatic product processing and storage. In particular, during the freezing processing and storage and transportation of pre-prepared conditioned crayfish, the changes in the water retention and antifreeze properties of the shrimp meat directly affect the quality characteristics of the product and the development of the crayfish processing industry. The phosphorus-containing water-retaining agents used in traditional production will make the product have a metallic astringent taste and rough texture, and long-term consumption of shrimp meat treated with phosphorus-containing water-retaining agents is not good for health. Therefore, it is urgent to find a green and efficient antifreeze and water-retaining method to effectively maintain the nutritional and texture quality of pre-prepared conditioned crayfish frozen products while ensuring safety.

[0004] At present, the domestic public invention patent "Antifreeze and water-retaining agent for frozen aquatic products, preparation method and application thereof" (CN201610302141.8) discloses the formula composition of an antifreeze and water-retaining agent, but does not involve the application of physical field processing technology. The domestic public invention patent "A preparation method of a nano water-retaining agent and its application in quick-frozen crustacean shrimp products" (CN201911075891.6) also only discloses a preparation method of an antifreeze and water-retaining agent, and does not involve the combined application with physical field processing technology. The green and efficient method for improving the antifreeze and water-retaining properties of prefabricated conditioned crayfish involved in the present invention has not been reported. Summary of the invention

[0005] Technical issues

[0006] The purpose of the present invention is to provide a green and efficient method for improving the antifreeze water retention of pre-prepared conditioned crayfish. The present invention uses variable frequency ultrasound to pre-treat crayfish with green antifreeze agent, and uses the mechanical effect and cavitation effect of ultrasound to assist the impregnation solution to penetrate the shrimp shell, and form micro-channels in the gaps of the muscle tissue of the crayfish, which is conducive to the infiltration of trehalose and alginate oligosaccharides. At the same time, secondary variable frequency ultrasound assisted impregnation promotes the free hydroxyl groups of trehalose and alginate oligosaccharides to bind to protein molecules, so that the protein is in a saturated state, enhances the structural stability of protein molecules, avoids aggregation and denaturation between proteins, and protects the muscle fiber structure of crayfish from being destroyed. After being treated with the method of the present invention, the thawing and cooking loss rate of pre-prepared conditioned crayfish can be significantly reduced, and the texture characteristics of its frozen product can be effectively maintained.

[0007] Technical Solution

[0008] The present invention provides a green and efficient method for improving the antifreeze water retention of pre-prepared conditioned crayfish, comprising the following steps:

[0009] Select mature and fresh crayfish as raw materials, wash, remove the shrimp whiskers and tail wings, and then perform frequency conversion ultrasonic assisted immersion treatment. In the first stage, the pre-treated crayfish is placed in trehalose with a mass fraction of 0.3%-0.9%, the material-liquid ratio is 1:5, the solution temperature is set at 45-55℃, the ultrasonic frequency is 45KHz, and the power density is 0.35-0.42W / cm 2 , the treatment time is 5-8min; in the second stage, the crayfish is taken out and placed in a 0.8%-1.3% alginate oligosaccharide solution with a solid-liquid ratio of 1:5, the solution temperature is set at 58-64°C, the ultrasonic frequency is 20KHz, and the power density is 0.55-0.62W / cm 2 , the processing time is 6-8min.

[0010] Beneficial Effects

[0011] The beneficial effect of the present invention is that the frequency conversion ultrasonic assisted impregnation green antifreeze water retaining agent treatment method of the present invention can effectively reduce the thawing and cooking loss rate of pre-prepared conditioned crayfish, and effectively maintain the texture characteristics of its frozen product, which is verified from the following aspects:

[0012] (1) Cooking loss rate of pre-processed crayfish: After testing the cooking loss rate, it was found that the cooking loss rate of the pre-processed crayfish treated with the present invention was reduced by 3%-5% compared with the traditional sodium pyrophosphate treatment. Compared with the untreated sample, the cooking loss rate of the pre-processed crayfish treated with the present invention was reduced by 12%-16%.

[0013] (2) Thawing loss rate of pre-prepared conditioned crayfish: After thawing loss rate testing, compared with the traditional sodium pyrophosphate treatment, the present invention reduces the thawing loss rate of pre-prepared conditioned crayfish by 2%-4%. Compared with the untreated sample, the present invention reduces the thawing loss rate of pre-prepared conditioned crayfish by 10%-15%.

[0014] (3) Texture retention rate of pre-prepared conditioned crayfish: The muscle elasticity test of the product showed no significant difference compared with the traditional sodium pyrophosphate treatment. Compared with the untreated sample, the present invention increased the muscle elasticity of the pre-prepared conditioned crayfish product by 13%-18%.

[0015] In summary, the variable frequency ultrasonic assisted impregnation green antifreeze water retaining agent method of the present invention can effectively reduce the thawing and cooking loss rate of pre-prepared conditioned crayfish while effectively maintaining the texture characteristics of the frozen product. DETAILED DESCRIPTION

[0016] The following examples can provide a better understanding of the present invention, but are not intended to limit the present invention in any way.

[0017] Example

[0018] 1. Raw material selection, cleaning and cutting: Select mature and fresh crayfish as raw materials, clean them, and remove the shrimp whiskers and tail fins.

[0019] 2. Frequency conversion ultrasonic assisted immersion treatment: In the first stage, the pre-treated crayfish was placed in trehalose with a mass fraction of 0.6%, the solid-liquid ratio was 1:5, the solution temperature was set at 47°C, the ultrasonic frequency was 45KHz, and the power density was 0.38W / cm 2 , the treatment time is 6min; in the second stage, the crayfish is taken out and placed in a 0.8% alginate oligosaccharide solution with a solid-liquid ratio of 1:5, the solution temperature is set at 59°C, the ultrasonic frequency is 20KHz, and the power density is 0.58W / cm 2 , the processing time is 7min.

[0020] 3. Seasoning, cooking and cooling: Place the soaked crayfish into a boiling cooking liquid with a concentration of 0.15% of thirteen-spice seasoning, with a material-liquid ratio of 1:4, and cook for 6 minutes, then take out and cool to room temperature.

[0021] 4. Liquid nitrogen quick freezing: Use spray-type liquid nitrogen quick freezing, precooling time is 30 minutes, the cavity temperature reaches -90℃, and the sample is taken out after 30 minutes of liquid nitrogen quick freezing.

[0022] 5. Packaging and freezing: The prepared quick-frozen crayfish product is vacuum-packed and finally frozen and stored at -20°C for 6 weeks.

[0023] 6. Related index detection: The cooking loss rate of the pre-prepared conditioned crayfish products prepared by the above method is 3.5% lower than that of the samples in the traditional sodium pyrophosphate treatment group, and 14.2% lower than that of the untreated group; the thawing loss rate of the pre-prepared conditioned crayfish products is 2.5% lower than that of the samples in the traditional sodium pyrophosphate treatment group, and 12.6% lower than that of the untreated group; the elasticity of the pre-prepared conditioned crayfish products is not significantly different from that of the samples in the traditional sodium pyrophosphate treatment group, and is 15.6% lower than that of the untreated group. These results show that variable frequency ultrasonic assisted immersion treatment can effectively maintain the texture quality of pre-prepared conditioned crayfish while reducing the cooking loss rate and thawing loss rate of crayfish. The specific index determination method is as follows:

[0024] ① Cooking loss rate (%): Take out the crayfish sample that has been treated with variable frequency ultrasonic assisted immersion and drain it, wipe it with gauze, and weigh it as M1 (accurate to 0.001g); cool the cooked crayfish sample to room temperature (25℃), wipe it with gauze to remove the moisture, and weigh it as M2 (accurate to 0.001g). The cooking loss rate (%) calculation formula is as follows:

[0025] Cooking loss rate (%) = (M1-M2) / M1×100

[0026] ② Thawing loss rate (%): Cool the boiled crayfish sample to room temperature (25°C), wipe off the moisture with gauze, weigh and record it as M2 (accurate to 0.001g); take out the crayfish sample that has been frozen and stored at -20°C for 6 weeks and place it in a culture dish, thaw it for 2h, wipe off the moisture with gauze, weigh and record it as M3 (accurate to 0.001g). The calculation formula of thawing loss rate (%) is as follows:

[0027] Thawing loss rate (%) = (M2-M3) / M2×100

[0028] ③ Texture (elasticity) determination: Select the pre-prepared conditioned crayfish shrimp part as the sample to be tested, and place it at room temperature (about 25°C) for 2 hours before the test to eliminate the influence of low temperature. Use the texture analyzer to measure 8 times in parallel and take the average value. The test conditions are as follows: the probe model is a P / 5N cylindrical probe, the operation mode is to measure the force during the downward pressure process, the pre-measurement speed is 1.0mm / s, the test speed is 1.0mm / s, the return speed after the test is 1.0mm / s, the test distance is 60% of the shrimp deformation, the holding time is 5s, and the trigger force is 5g.

Claims

1. A green and efficient method for improving the antifreeze water retention of pre-prepared conditioned crayfish, characterized in that: Select mature and fresh crayfish as raw materials, wash, remove shrimp whiskers and tail wings, and then carry out frequency conversion ultrasonic assisted immersion treatment. In the first stage, the pretreated crayfish is placed in trehalose with a mass fraction of 0.3%-0.9%, the material-liquid ratio is 1:5, the solution temperature is set at 45-55℃, the ultrasonic frequency is 45KHz, and the power density is 0.35-0.42W / cm 2 , the treatment time is 5-8min; in the second stage, the crayfish is taken out and placed in a 0.8%-1.3% alginate oligosaccharide solution with a solid-liquid ratio of 1:5, the water temperature is set to 58-64℃, the ultrasonic frequency is 20KHz, and the power density is 0.55-0.62W / cm 2 , the processing time is 6-8min.

2. The prepared cooked crayfish product prepared according to claim 1.