Frozen fried powder-coated oysters and processing method thereof

Abstract

The invention discloses frozen fried powder-coated oysters and a processing method thereof, and belongs to the technical field of food processing. Oyster meat pretreated by an ice-water mixed solution is used as a raw material, a dry-wet-dry three-time powder coating process is innovatively applied to the oyster meat, primary powder coating is used for controlling moisture, wet powder coating is used for locking meat juice, secondary powder coating is used for adding a crispy outer layer, and then primary frying shaping and microwave light frying technologies are combined for frying. And quickly freezing the single bodies to obtain the frozen fried powder-coated oysters. According to the frozen fried powder-coated oyster, on the basis that the freshness and the nutritional value of oyster meat are effectively kept, the taste level of the oyster is improved through a unique powder coating process and a combined frying mode, and meanwhile, harmful substances and nutrition loss possibly generated by traditional high-temperature frying are avoided; the taste, the flavor, the nutritional value and the food safety are remarkably optimized, and the requirements of modern consumers for high-quality and high-nutrition value of oyster products and the pursuit of rich taste and flavor are met.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, and particularly relates to a frozen fried oyster coated with flour and a processing method thereof. Background Art

[0002] Oyster (Ostrea gigas thunberg), also known as oyster and sea oyster, is a bivalve mollusk living in the ocean, belonging to the superfamily of oysters. It is famous for its plump meat and high nutritional value. It is not only rich in protein, taurine, vitamins and minerals, but also has a variety of functional active substances, such as antioxidant, anti-inflammatory, anti-hypertensive, etc. The global oyster farming market has reached 51.772 billion yuan. As one of the world's largest oyster farming countries, China has rich marine resources and advanced farming technology, and its output and quality are among the best in the world. The oyster farming area in my country continues to grow, from 130,200 hectares in 2015 to 235,000 hectares in 2022. By 2023, the market size has reached 33.671 billion yuan.

[0003] With the progress of the times, choosing convenient and fast food has become a trend of mass consumption. Many countries have developed a large number of oyster products with oysters as the main raw material. Despite the broad market prospects, the oyster products industry still faces some challenges and shortcomings. As a highly nutritious aquatic product, oysters have the disadvantages of not being able to withstand storage and freezing, dying quickly after being taken out of the water, and being very easily contaminated by microorganisms. In addition, due to the soft tissue of oysters and high protein and water content, the development of oysters into food currently has the following main technical problems: First, mechanical damage during processing can easily cause the belly to break, and marinating or boiling is time-consuming and has low efficiency in flavoring; second, the use of heat transfer methods such as ovens during processing can easily cause uneven heating inside and outside and shrinkage, affecting the taste and appearance quality; third, the steps in the oyster food processing process are relatively complicated, and due to equipment and technical limitations, production is discontinuous, inefficient, and costly.

[0004] Affected by these processing technology factors, at present, the varieties of oyster processing in my country are relatively single, and less than 14% of oysters are used for processing, mainly for processing into low-end products such as oyster sauce and dried oysters. High-end products have not yet formed a large-scale industry, and there is a lack of high value-added deep-processing products. In addition, the application of oysters in nutrition and functional foods is very limited. Although oyster peptides and polysaccharides have been proven to have multiple functional activities, the development of related products is insufficient. Therefore, improving the processing technology and product added value of oyster products and developing high-end oyster products are the key to the future development of the industry.

[0005] In the existing aquatic product processing technology, there are many ways to process aquatic products, such as boiling, frying, smoking and drying. In the field of frying processing of aquatic products, traditional breaded products usually only involve simple breading and frying processes. For example, the Chinese patent with publication number CN113678991A and application date August 31, 2021 discloses "a method for preparing fried breaded aquatic products", adding umami shrimp peptides to improve the umami taste of aquatic products and retain the nutritional value of aquatic products; the Chinese patent with publication number CN115969015A and application date October 26, 2022 discloses "a fried breaded sea shrimp and preparation method", adding cooked highland barley flour to the breading formula to reduce the oil content of fried sea shrimp, but the above-mentioned traditional high-temperature frying process may cause some nutrients in aquatic products, such as vitamins and proteins, to denature or lose, thereby affecting the nutritional value of the aquatic products themselves.

[0006] A Chinese patent with publication number CN117814449A and application date of February 5, 2024 discloses "a method for preparing breaded and seasoned fish". By optimizing the seasoning formula, a breaded fish product with uniform flavor and regular shape is achieved, the batter formula and refrigeration time are optimized to make the batter layer more uniform, the product appearance and taste better, and the frying process parameters are precisely controlled to ensure that the product is golden in color and has a unique flavor. However, frying after high-temperature steaming further aggravates the loss of water in the fish, causing it to become drier and harder, losing its original tender and smooth taste, and excessive heat treatment may cover up the natural delicious flavor of the fish.

[0007] Oyster products themselves contain high fat and water content, and are prone to oxidation reactions during traditional frying processes, resulting in unpleasant rancid tastes, affecting the taste of the product, and also lacking in the retention of nutrients and health value. For example, traditional breaded products often use high-temperature frying, which not only causes the loss of oyster nutrients, but also may produce trans fatty acids that are unhealthy. In addition, traditional oyster products often lack the corresponding regulation of raw material freshness, frying conditions, and breaded ingredients and methods during frying processes, which leads to uneven taste, flavor, and nutritional value of the final oyster products. For example, a Chinese patent with publication number CN103393160A, filed on June 24, 2013, provides a processing method for instant bamboo charcoal oysters, which uses dried oysters as raw materials, wraps and fries, and cannot directly identify oysters. The product is black and affects the senses. After direct frying, the oil content is high, and long-term storage is easily oxidized, which is not suitable for long-term storage.

[0008] Limited by the lack of suitable and effective frying process methods, there is still a large gap in the research on oyster fried products and their preparation methods. Therefore, creating a frying process method that can maintain the delicious taste and nutritional value of oysters, while improving the safety, health and flavor richness of oyster products, can provide a good reference value for the development of oyster processing technology and bring significant economic benefits to oyster-related industries. Summary of the invention

[0009] In order to solve the problems existing in the prior art, the present invention provides a frozen fried breaded oyster and a processing method thereof, which improves the taste of the oysters through a unique breading process and a combined frying method, while avoiding the harmful substances and nutrient loss that may be produced by traditional high-temperature frying. The frozen fried breaded oysters are significantly optimized in terms of taste, flavor, nutritional value and food safety.

[0010] The technical solution of the present invention is as follows:

[0011] One of the purposes of the present invention is to provide a method for processing frozen fried breaded oysters, which uses oyster meat pretreated with an ice-water mixture as a raw material, applies a dry-wet-dry three-time breading process to it, and then combines initial frying and shaping and microwave light frying technology to fry, and then quickly freezes the individual pieces to obtain the frozen fried breaded oysters, comprising the following steps:

[0012] S1. Pretreatment: fresh oyster meat is selected according to the weight difference, and pretreated in an ice-water mixture until the core temperature is no higher than 4°C;

[0013] S2, initial powder coating: drain the fresh oyster meat pre-treated in S1 for 5-10 minutes before coating, and then place it on a gradient conveyor belt that is pre-evenly covered with dry powder. The upper end of the conveyor belt is sprayed with powder from top to bottom so that it is fully coated with powder during the conveying process;

[0014] S3, wet powder coating: the oyster meat fully coated with powder is transferred and immersed in a hydrated paste mixture composed of ice water mixture and dry powder for 2 to 5 minutes, and the temperature of the mixture is controlled at 10 to 21°C to make it fully soaked and coated with powder;

[0015] S4, re-coating with powder: after being coated with batter in S3, the oyster meat is again placed on a gradient conveyor belt that is pre-evenly covered with dry powder via a conveyor belt, and the upper end of the conveyor belt is sprayed with powder from top to bottom so that the oyster meat is fully coated with powder during the conveying process;

[0016] S5, initial frying and shaping: the oyster meat after being coated with flour and starch in S4 is passed through a hollow conveyor belt to remove excess dry flour on the surface and is conveyed to a fryer for frying and shaping;

[0017] S6, microwave light frying: placing the oysters coated with flour after frying and shaping in S5 into a frying basket for microwave-assisted vacuum frying;

[0018] S7, draining oil and cooling: after microwave frying, the oysters are centrifugally deoiled under vacuum conditions of 0.080-0.095 MPa, and cooled to room temperature to obtain fried breaded oysters;

[0019] S8, quick freezing and packaging: cooling the fried breaded oysters obtained in S7, placing them in an aluminum plate quick freezing room for individual quick freezing, packaging them in sealed bags and then freezing them, thus obtaining the frozen fried breaded oysters.

[0020] Furthermore, the dry powder formula for the initial coating in S2 is as follows: 50-60 parts of wheat flour, 10-20 parts of corn starch, and 10-20 parts of sweet potato starch.

[0021] Furthermore, the formula of the hydrated paste mixture of the wet powder slurry in S3 is as follows: 70-90 parts of ice-water mixture, 60-80 parts of wheat flour, 10-20 parts of potato starch, 10-20 parts of cassava hydrogenated hydroxypropyl starch, 3-6 parts of egg liquid, 3-6 parts of spices, 1-3 parts of salt, 1-3 parts of chicken essence, 0.3-0.5 parts of cyclodextrin, 0.3-0.5 parts of konjac flour, and 0.3-0.5 parts of β-glucan.

[0022] Furthermore, the dry powder formula of the coating powder in S4 is as follows: 45-60 parts of medium-gluten flour, 30-40 parts of high-amylose corn starch, and 30-40 parts of bread crumbs.

[0023] Furthermore, the conveyor belt speed is 4-21 m / min, the temperature during the conveying process is controlled to be 4-10° C., the powder spraying time is 5-8 min, and the powder coating thickness is 1-3 mm.

[0024] Furthermore, palm oil is used for initial frying in S5, the frying oil temperature is 172-180° C., the frying time lasts 65-80 seconds, and after the center temperature of the oyster meat reaches 70.6° C., the frying time lasts 15 seconds.

[0025] Furthermore, during microwave light frying in S6, the frequency of the ultrasonic generator is 20-30kHz, the ultrasonic operating power is 100-300W, the microwave operating power is 2400-3000W, the frying temperature is 100-120°C, the vacuum degree is controlled at 0.080-0.095MPa, and the equipment operating time is 5-10min.

[0026] Furthermore, the centrifugal deoiling condition in S7 is a centrifugal time of 3 to 5 minutes at a rotation speed of 300 to 500 r / min.

[0027] Furthermore, the single quick-freezing time in S8 is 3 to 5 hours, the temperature of the aluminum plate quick-freezing room is maintained below -30°C, and when the center temperature of the fried and breaded oysters drops below -18°C, they are packaged and sealed in an environment with a temperature below 15°C, and then frozen at below -18°C.

[0028] Furthermore, the frozen semi-finished product is weighed according to a specified weight, put into a plastic bag, and the plastic bag is heat-sealed with a sealing machine.

[0029] A second object of the present invention is to provide a frozen fried breaded oyster.

[0030] Furthermore, the frozen fried breaded oysters are superior to the frozen fried breaded oysters prepared by the conventional process in terms of the contents of aldehydes, alcohols, ketones, hydrocarbons, esters and acid compounds.

[0031] Compared with the prior art, the beneficial effects of the present invention are:

[0032] 1. The present invention first uses fresh oyster meat as raw material, and pre-treats it with ice-water mixture to reduce the surface moisture and form a thin layer of ice, which effectively maintains the freshness and nutritional value of the oyster meat. Then, a three-time dry-wet-dry powder coating process is innovated and applied to the pre-treated oyster meat, wherein the oyster meat with a thin ice layer on the surface can better absorb dry powder during the initial powder coating process, forming a preliminary outer layer protection, and absorb excess surface moisture to achieve the purpose of water control; wet powder slurry makes the oyster meat with appropriate dry and wet conditions after the initial powder coating fully soaked and wrapped with slurry water, tightly locks the internal moisture of the oyster meat, avoids excessive water loss in subsequent frying, resulting in a hard taste, and enhances the fresh and tender taste of the meat; the final re-coating adds a crispy outer layer to the oyster meat. The unique powder coating process and powder slurry composition of the present invention not only enhance the taste level of oysters, but also help to lock the fat, moisture and nutrients of the oyster meat itself, reduce the loss of nutrients or excessive water loss in the subsequent processing process, and significantly improve the flavor, taste and nutritional value of the final product.

[0033] 2. The present invention proposes for the first time to combine initial frying and microwave light frying technology to fry oysters that have been coated with flour three times. This new combined frying method not only ensures the shaping and doneness of the oysters, but also reduces the use of oil through microwave-assisted vacuum frying, thereby reducing the oil content of the final oyster product. Initial frying and shaping uses a short period of high-temperature frying to quickly lock in the oyster's flavor and nutrients using the three layers of powder coating, thereby preventing the oyster's own fat and moisture from oxidizing during the frying process and producing a rancid smell. Microwave light frying avoids the harmful substances that may be produced by traditional high-temperature frying in a vacuum environment, while maintaining the fresh and tender taste of the oysters by regulating the combination of microwave-related operating parameters. This innovative combined frying process makes oyster products healthier while maintaining their deliciousness, meeting the needs of modern consumers for healthy food.

[0034] 3. The processing technology of frozen fried breaded oysters disclosed in the present invention improves the processing technology and product added value of oyster products, and makes up for the defects of the traditional oyster processing method being relatively single and mainly low-end products. The high-end oyster products, frozen fried breaded oysters developed by the present invention, improve the taste level and delicious flavor of oysters, while avoiding the harmful substances and nutrient loss that may be produced by traditional high-temperature frying, and have been significantly improved in taste, flavor, nutritional value and food safety. The present invention not only enriches the varieties of oyster processing and enhances the market competitiveness of products, but also opens up a new direction for the development of the oyster products industry, meets the modern consumers' demand for high quality and high nutrition value of oyster products and the pursuit of enriched taste and flavor, helps to promote the upgrading of the oyster industry, and brings more economic benefits to oyster farmers and related enterprises. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a comparison chart of the relative contents of the components of the frozen fried breaded oysters prepared in Examples 1-3 of the present invention and Comparative Example 1;

[0036] Figure 2 This is a finished product picture of the frozen fried breaded oysters prepared in Example 1 of the present invention;

[0037] Figure 3 This is a finished picture of the frozen fried breaded oysters prepared in Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0038] The present invention is further described below in conjunction with preferred embodiments. The endpoints of the ranges disclosed in the present invention and any values ​​are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be deemed to be specifically disclosed herein.

[0039] The experimental methods in the following examples, unless otherwise specified, are conventional methods and are performed according to the techniques or conditions described in the literature in the art or according to the product instructions.

[0040] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

[0041] Example 1

[0042] The present embodiment provides a frozen fried breaded oyster, the process of which comprises the following steps:

[0043] S1. Pretreatment: fresh oyster meat is selected according to the weight difference, and pretreated in an ice-water mixture until the core temperature is no higher than 4°C;

[0044] S2, initial powder coating: drain the fresh oyster meat pre-treated in S1 for 5 minutes before coating, and then place it on a gradient conveyor belt that is pre-evenly covered with dry powder. Spray powder from the top of the conveyor belt at 4°C and 8m / min for 5 minutes, so that it is fully coated with a 1mm powder layer during the conveying process. The dry powder formula is as follows: 50 parts of wheat flour, 10 parts of corn starch, and 10 parts of sweet potato starch;

[0045] S3, wet powder coating: the oyster meat fully coated with powder is transferred and immersed in a hydrated paste mixture composed of an ice-water mixture and dry powder for 2 minutes, and the mixture temperature is controlled at 10°C to make it fully soaked and coated. The formula of the hydrated paste mixture is as follows: 70 parts of ice-water mixture, 60 parts of wheat flour, 10 parts of potato starch, 10 parts of tapioca hydrogenated hydroxypropyl starch, 3 parts of egg liquid, 3 parts of spices, 1 part of salt, 1 part of chicken essence, 0.3 parts of cyclodextrin, 0.3 parts of konjac powder, and 0.3 parts of β-glucan;

[0046] S4, re-coating with powder: after the batter coating in S3, the oyster meat is placed on a gradient conveyor belt that is pre-evenly covered with dry powder. The upper end of the conveyor belt is sprayed with powder from top to bottom at 8°C and 20m / min for 5min, so that the oyster meat is fully coated with 1mm powder during the conveying process. The dry powder formula is as follows: 45 parts of medium-gluten flour, 30 parts of high-amylose corn starch, and 30 parts of bread crumbs;

[0047] S5, initial frying and shaping: After being coated with flour and starch in S4, the oyster meat is passed through a hollow conveyor belt to remove excess dry flour on the surface, and then conveyed to a fryer and fried at 172°C for 65 seconds. After the center temperature of the oyster meat reaches 70.6°C, fry for 15 seconds to shape the oyster;

[0048] S6, microwave light frying: put the oysters coated with flour after frying and shaping in S5 into a frying basket for microwave-assisted vacuum frying, wherein the frequency of the ultrasonic generator is 20kHz, the ultrasonic operating power is 100W, the microwave operating power is 2400W, the frying temperature is 100°C, the vacuum degree is controlled at 0.080-0.095MPa, and the equipment operation time is 5min;

[0049] S7, draining oil and cooling: after microwave frying, the oysters are centrifuged to remove oil for 3 minutes at a speed of 300 r / min under a vacuum condition of 0.080-0.095 MPa, and cooled to room temperature, thereby obtaining fried breaded oysters;

[0050] S8, quick freezing and packaging: Cool the fried breaded oysters obtained in S7, and place them in an aluminum plate quick freezing room where the temperature is maintained below -30°C for individual quick freezing for 3 hours, and when the center temperature of the fried breaded oysters drops below -18°C, package and seal them in an environment with a temperature below 15°C, and store them in a frozen state below -18°C. This is the frozen fried breaded oysters.

[0051] Example 2

[0052] The present embodiment provides a process for deep-frying frozen breaded oysters, comprising the following steps:

[0053] S1. Pretreatment: fresh oyster meat is selected according to the weight difference, and pretreated in an ice-water mixture until the core temperature is no higher than 4°C;

[0054] S2, initial powder coating: drain the fresh oyster meat pretreated in S1 for 7 minutes before coating, and then place it on a gradient conveyor belt that is pre-evenly covered with dry powder. Spray powder from the top of the conveyor belt at 7°C and 12m / min for 6 minutes, so that it is fully coated with a 1.5mm powder layer during the conveying process. The dry powder formula is as follows: 55 parts of wheat flour, 15 parts of corn starch, and 15 parts of sweet potato starch;

[0055] S3, wet powder coating: the oyster meat fully coated with powder is transferred and immersed in a hydrated paste mixture composed of an ice-water mixture and dry powder for 4 minutes, and the mixture temperature is controlled at 16°C to make it fully soaked and coated. The formula of the hydrated paste mixture is as follows: 80 parts of ice-water mixture, 70 parts of wheat flour, 15 parts of potato starch, 15 parts of tapioca hydrogenated hydroxypropyl starch, 4 parts of egg liquid, 4 parts of spices, 2 parts of salt, 2 parts of chicken essence, 0.4 parts of cyclodextrin, 0.4 parts of konjac powder, and 0.4 parts of β-glucan;

[0056] S4, re-coating with powder: after the batter coating in S3, the oyster meat is placed on a gradient conveyor belt that is pre-evenly covered with dry powder. The upper end of the conveyor belt is sprayed with powder from top to bottom at 7°C and 12m / min for 6min, so that the oyster meat is fully coated with 1.5mm powder during the conveying process. The dry powder formula is as follows: 50 parts of medium-gluten flour, 35 parts of high-amylose corn starch, and 35 parts of bread crumbs;

[0057] S5, initial frying and shaping: After being coated with flour and starch in S4, the oyster meat is passed through a hollow conveyor belt to remove excess dry flour on the surface, and then conveyed to a fryer and fried at 176°C for 70 seconds. After the center temperature of the oyster meat reaches 70.6°C, fry for 15 seconds to shape the oyster;

[0058] S6, microwave light frying: put the oysters coated with flour after frying and shaping in S5 into a frying basket for microwave-assisted vacuum frying, wherein the frequency of the ultrasonic generator is 25kHz, the ultrasonic operating power is 200W, the microwave operating power is 2700W, the frying temperature is 110°C, the vacuum degree is controlled at 0.080-0.095MPa, and the equipment operation time is 7min;

[0059] S7, draining oil and cooling: after light microwave frying, the oysters are centrifuged to remove oil for 4 min at a speed of 400 r / min under a vacuum condition of 0.080-0.095 MPa, and cooled to room temperature, thereby obtaining fried breaded oysters;

[0060] S8, quick freezing and packaging: Cool the fried breaded oysters obtained in S7, and place them in an aluminum plate quick freezing room where the temperature is maintained below -30°C for 4 hours, and when the center temperature of the fried breaded oysters drops below -18°C, package and seal them in an environment with a temperature below 15°C, and store them in frozen form at a temperature below -18°C. This is the frozen fried breaded oysters.

[0061] Example 3

[0062] The present embodiment provides a frozen fried breaded oyster, the process of which comprises the following steps:

[0063] S1. Pretreatment: fresh oyster meat is selected according to the weight difference, and pretreated in an ice-water mixture until the core temperature is no higher than 4°C;

[0064] S2, initial powder coating: drain the fresh oyster meat pretreated in S1 for 10 minutes before coating, and then place it on a gradient conveyor belt that is pre-evenly covered with dry powder. Spray powder from the top of the conveyor belt at 10°C and 21m / min for 8 minutes, so that it is fully coated with a 3mm powder layer during the conveying process. The dry powder formula is as follows: 60 parts of wheat flour, 20 parts of corn starch, and 20 parts of sweet potato starch;

[0065] S3, wet powder coating: the oyster meat fully coated with powder is transferred and immersed in a hydrated paste mixture composed of an ice-water mixture and dry powder for 5 minutes, and the mixture temperature is controlled to be 21°C to make it fully soaked and coated with powder. The formula of the hydrated paste mixture is as follows: 90 parts of ice-water mixture, 80 parts of wheat flour, 20 parts of potato starch, 20 parts of tapioca hydrogenated hydroxypropyl starch, 6 parts of egg liquid, 6 parts of spices, 3 parts of salt, 3 parts of chicken essence, 0.5 parts of cyclodextrin, 0.5 parts of konjac powder, and 0.5 parts of β-glucan;

[0066] S4, re-coating with powder: after the batter coating in S3, the oyster meat is placed on a gradient conveyor belt that is pre-evenly covered with dry powder. The upper end of the conveyor belt is sprayed with powder from top to bottom at 10°C and 21m / min for 8min, so that the oyster meat is fully coated with 3mm powder during the conveying process. The dry powder formula is as follows: 60 parts of medium-gluten flour, 40 parts of high-amylose corn starch, and 40 parts of bread crumbs;

[0067] S5, initial frying and shaping: the oyster meat after being coated with flour in S4 is passed through a hollow conveyor belt to remove excess dry flour on the surface, and then conveyed to a fryer and fried at 180°C for 80 seconds. After the center temperature of the oyster meat reaches 70.6°C, frying is continued for 15 seconds to shape the oyster;

[0068] S6, microwave light frying: put the oysters coated with flour after frying and shaping in S5 into a frying basket for microwave-assisted vacuum frying, wherein the frequency of the ultrasonic generator is 30kHz, the ultrasonic operating power is 300W, the microwave operating power is 3000W, the frying temperature is 120°C, the vacuum degree is controlled at 0.080-0.095MPa, and the equipment operation time is 10min;

[0069] S7, draining oil and cooling: after microwave frying, the oysters are centrifuged to remove oil for 5 minutes at a speed of 500 r / min under a vacuum condition of 0.080-0.095 MPa, and cooled to room temperature, thereby obtaining fried breaded oysters;

[0070] S8, quick freezing and packaging: Cool the fried breaded oysters obtained in S7, and place them in an aluminum plate quick freezing room where the temperature is maintained below -30°C for individual quick freezing for 5 hours, and when the center temperature of the fried breaded oysters drops below -18°C, package and seal them in an environment with a temperature below 15°C, and store them in frozen form at a temperature below -18°C. This is the frozen fried breaded oysters.

[0071] Comparative Example 1

[0072] This comparative example provides a frozen fried breaded oyster, the process of which does not involve the specific technology of the frozen fried breaded oyster mentioned in the present invention, but adopts more common and basic breading and frying steps. It mainly includes the following steps:

[0073] First, clean the fresh oysters, open the shells and take out the meat, which are then simply classified and stored; then, coat the oyster meat directly with a layer of ordinary wheat flour and then fry it in hot oil until golden brown. During the frying process, the oil temperature is maintained at a high level to ensure that the oyster skin is crispy; finally, remove the fried oysters from the oil, wait for them to cool slightly, and then quickly freeze them to obtain traditional frozen fried flour-coated oysters.

[0074] Performance Testing

[0075] 1. Gas chromatography-mass spectrometry detection

[0076] The frozen fried breaded oysters described in Examples 1-3 were prepared respectively, and the frozen fried breaded oysters prepared by the conventional method in Comparative Example 1 were used as the corresponding test group. The four groups of frozen fried breaded oysters were measured by headspace solid phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS). The relative content of each component was determined by the internal standard method, and the internal standard concentration was 9.4×10 -4 mg / mL of cyclohexanone.

[0077] Headspace injection conditions: 2.5g of sample was accurately drawn, crushed and placed in a 40mL headspace bottle, and 2.5ml saturated sodium chloride solution and 100μL internal standard were added, sealed, placed in a magnetic stirrer at 65℃ for preheating equilibrium for 10min, the extraction head was inserted into the headspace bottle, injected after extraction for 30min, and removed after decomposition at 230℃ for 5min. Each component can be obtained by searching and analyzing the computer spectral library (NEST17), and compounds with a matching degree higher than 80% are selected. Two parallels are measured for each group of samples, and the average value is taken.

[0078] The relative content of flavor substances is calculated according to the following formula:

[0079]

[0080] Where: C x is the content of unknown flavor substances, μg / kg;

[0081] C0 is the mass concentration of internal standard cyclohexanone, μg / μL;

[0082] V0 is the injection volume of internal standard cyclohexanone, μL;

[0083] S x is the peak area of ​​the unknown flavor substance;

[0084] S0 is the peak area of ​​the added internal standard cyclohexanone;

[0085] m is the mass of sample added, kg.

[0086] Test results such as Figure 1 As shown, the types and contents of aldehydes, alcohols, ketones, hydrocarbons and acids in the frozen fried breaded oysters prepared in Examples 1-3 are dominant in the volatile compounds of the flavoring peptides, and together they form the unique flavor of the frozen fried breaded oysters.

[0087] First, from the content of aldehyde compounds, the contents of Example 1, Example 2 and Example 3 are 114.79, 205.51 and 297.64 ug / kg, respectively, while the content of Comparative Example 1 is 58.66 ug / kg. Aldehyde compounds are key factors affecting the flavor of aquatic products, and they are closely related to the rancid smell and earthy smell of aquatic products. The increase in the content of aldehyde compounds in Examples 1-3 may mean a richer aroma type, which helps to enhance the flavor of aquatic products; secondly, the content of alcohol compounds is also relatively high in the examples, which are 91.34, 104.82 and 97.96 ug / kg, respectively, while the content in Comparative Example 1 is 34.09 ug / kg. Alcohol compounds are mainly derived from the degradation of polyunsaturated fatty acids. Although their thresholds are relatively high, their contribution to the overall flavor of food cannot be ignored, especially in terms of increasing the complexity and depth of food; the content of ketone compounds also increased in the examples, which were 60.55, 105.85 and 136.11 ug / kg, respectively, while no ketone compounds were detected in Comparative Example 1. Ketone substances usually have a high threshold, but their presence may have a certain enhancement effect on the fishy smell. The increase in ketone compounds in Examples 1-3 may help balance and enhance the overall flavor; the content of hydrocarbon compounds in the examples is also significantly higher than that in the control examples, which are 1061.91, 1605.86 and 1273.73 ug / kg, respectively, while the content in Comparative Example 1 is 229.85 ug / kg. Hydrocarbon compounds contribute less to the flavor of the product, but their presence has a certain effect on the overall flavor; the content of ester compounds also increased in the examples, which were 1.96, 2.20 and 2.38 ug / kg, respectively, while no ester compounds were detected in Comparative Example 1. The ester compounds have a distinct aromatic flavor, which can mask the smell of corruption and enhance the flavor; the content of the acid compounds is also relatively high in Examples 1-3, which are 44.97, 44.43 and 80.84 ug / kg, respectively, compared with 1.40 ug / kg in Example 1. The acid compounds and other flavor substances work together to promote the flavor characteristics. In addition, other types of compounds such as pyrroles, pyrazines, amides, and furans were also detected in Examples 1-3. The flavor threshold of these substances is relatively low, and their contribution to the flavor of the frozen fried breaded oysters is relatively small.

[0088] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for processing frozen fried breaded oysters, characterized in that: Oyster meat pretreated with ice-water mixture is used as raw material, and a three-time dry-wet-dry powder coating process is applied to the oyster meat, and then fried in combination with initial frying and microwave light frying technology, and the frozen fried powdered oyster is obtained after single quick freezing, including the following steps: S1. Pretreatment: fresh oyster meat is selected according to the weight difference, and pretreated in an ice-water mixture until the core temperature is no higher than 4°C; S2, initial powder coating: drain the fresh oyster meat pre-treated in S1 for 5-10 minutes before coating, and then place it on a gradient conveyor belt that is pre-evenly covered with dry powder. The upper end of the conveyor belt is sprayed with powder from top to bottom so that it is fully coated with powder during the conveying process; S3, wet powder coating: the oyster meat fully coated with powder is transferred and immersed in a hydrated paste mixture composed of ice water mixture and dry powder for 2 to 5 minutes, and the temperature of the mixture is controlled at 10 to 21°C to make it fully soaked and coated with powder; S4, re-coating with powder: after being coated with batter in S3, the oyster meat is again placed on a gradient conveyor belt that is pre-evenly covered with dry powder via a conveyor belt, and the upper end of the conveyor belt is sprayed with powder from top to bottom so that the oyster meat is fully coated with powder during the conveying process; S5, initial frying and shaping: the oyster meat after being coated with flour and starch in S4 is passed through a hollow conveyor belt to remove excess dry flour on the surface and is conveyed to a fryer for frying and shaping; S6, microwave light frying: placing the oysters coated with flour after frying and shaping in S5 into a frying basket for microwave-assisted vacuum frying; S7, draining oil and cooling: after microwave frying, the oysters are centrifugally deoiled under vacuum conditions of 0.080-0.095 MPa, and cooled to room temperature to obtain fried breaded oysters; S8, quick freezing and packaging: cooling the fried breaded oysters obtained in S7, placing them in an aluminum plate quick freezing room for individual quick freezing, packaging them in sealed bags and then freezing them, thus obtaining the frozen fried breaded oysters.

2. The method for processing frozen fried breaded oysters according to claim 1, characterized in that: The dry powder formula of the initial coating in S2 is as follows by weight: 50-60 parts of wheat flour, 10-20 parts of corn starch, and 10-20 parts of sweet potato starch.

3. The method for processing frozen fried breaded oysters according to claim 1, characterized in that: Calculated by weight, the formula of the hydrated paste mixture in the wet powder slurry in S3 is as follows: 70-90 parts of ice-water mixture, 60-80 parts of wheat flour, 10-20 parts of potato starch, 10-20 parts of cassava hydrogenated hydroxypropyl starch, 3-6 parts of egg liquid, 3-6 parts of spices, 1-3 parts of salt, 1-3 parts of chicken essence, 0.3-0.5 parts of cyclodextrin, 0.3-0.5 parts of konjac flour, and 0.3-0.5 parts of β-glucan.

4. The method for processing frozen fried breaded oysters according to claim 1, characterized in that: The dry powder formula of the coating powder in S4 is as follows by weight: 45-60 parts of medium-gluten flour, 30-40 parts of high-amylose corn starch, and 30-40 parts of bread crumbs.

5. The method for processing frozen fried breaded oysters according to claim 1, characterized in that: The conveyor belt speed is 4-21 m / min, the temperature during the conveying process is controlled to be 4-10° C., the powder spraying time is 5-8 min, and the powder coating thickness is 1-3 mm.

6. The method for processing frozen fried breaded oysters according to claim 1, characterized in that: In S5, palm oil is used for initial frying and shaping, the frying oil temperature is 172-180° C., the frying time lasts for 65-80 seconds, and after the center temperature of the oyster meat reaches 70.6° C., the frying time lasts for 15 seconds.

7. The method for processing frozen fried breaded oysters according to claim 1, characterized in that: During microwave light frying in S6, the frequency of the ultrasonic generator is 20-30kHz, the ultrasonic operating power is 100-300W, the microwave operating power is 2400-3000W, the frying temperature is 100-120°C, the vacuum degree is controlled at 0.080-0.095MPa, and the equipment operating time is 5-10min.

8. The method for processing frozen fried breaded oysters according to claim 1, characterized in that: The centrifugal deoiling condition in S7 is a centrifugal time of 3 to 5 minutes at a rotation speed of 300 to 500 r / min.

9. The method for processing frozen fried breaded oysters according to claim 1, characterized in that: The single quick freezing time in S8 is 3 to 5 hours, and the temperature of the aluminum plate quick freezing room is maintained below -30°C. When the center temperature of the fried and breaded oysters drops to below -18°C, they are packaged and sealed in an environment with a temperature below 15°C, and then frozen at below -18°C.

10. Frozen fried breaded oysters prepared by the processing method according to any one of claims 1 to 9.

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