Method for preparing fragrant and crispy fish scales through combination of medium-temperature plasticizing and high-temperature crisping

Abstract

The invention belongs to the technical field of food processing, and particularly relates to a method for preparing fragrant and crispy fish scales through combination of medium-temperature plasticizing and high-temperature crisping. Fish scales are used as raw materials, salt, cooking wine, starch and other auxiliary materials are matched, and the crispy and fragrant fish scales are prepared through the processes of low-salt pre-pickling water control, powder wrapping, medium-temperature plasticizing combined with high-temperature dehydration crisping, high-temperature re-frying oil control, coloring, deoiling, seasoning and the like. The invention solves the problems that the finished product is not crisp enough when the fish scales are used as raw materials to make leisure food, and the original nutrition, flavor and form of the fish scales are difficult to retain.

Description

Technical Field

[0001] The invention belongs to the technical field of food processing, and particularly relates to a method for preparing crispy fish scales by combining medium-temperature plasticization with high-temperature crisping. Background Art

[0002] my country is rich in freshwater fish resources. In 2021, my country's freshwater fish production reached 27.3231 million tons. During the processing of fish, 40% to 60% of by-products (including fish skin, fish scales, fish bones, fish fins, fish tails, etc.) are produced. Among them, fish scales are the main by-products in the processing of scaly fish, accounting for about 5% of the fish body. In 2021, the total output of farmed freshwater fish in my country reached 26.4028 million tons, of which about 23.3713 million tons were scaled fish. Calculated at a weight share of 5%, my country's freshwater fish scale production in 2021 was about 1.1686 million tons. However, in the daily fresh sales and small-scale catering processing, fish scales are often treated as waste.

[0003] Fish scales are rich in collagen, amino acids, lecithin and various minerals, and also have certain medicinal value. As early as in the "Compendium of Materia Medica" and "Famous Doctors' Records", it was described that fish scales have certain effects on anemia, leukemia and postpartum blood fainting. Modern research shows that fish scales also have the effects of preventing and treating vascular sclerosis, anti-cancer, anti-aging, and lowering blood lipids. At present, the development and utilization of fish scales mainly focus on extracting collagen, extracting hydroxy limestone, producing fish scale glue, extracting fish silver, etc., which can be used in beauty, medicine, food additives and other fields. At the same time, fish scales are also a high-quality food processing raw material, often used to process into pre-prepared food products such as fish scale jelly, fish scale soup, and fish scale jelly, but there is less research on the development of related leisure fish scale foods.

[0004] Snack foods are foods eaten when people are free and resting. With the improvement of living standards, snack foods are deeply loved by the general public, and the consumption quantity and quality requirements are constantly improved. If fish scales are processed into a kind of snack food with crisp taste, nutrition and health, it can not only enrich the types of snack foods, but also solve the problem of large-scale loss of fish scale resources and difficulty in high-value utilization. In the prior art, there are only a few reports on the technical scheme of processing snack foods with fish scales as raw materials. Among them, Chen Xiaolei (invention name: a processing method of instant fish scale food, publication number CN108371303A) uses fresh fish scales as raw materials, and obtains instant fish scale food with both delicate taste of fish scale jelly and crispy taste of fish scale crisp skin through screening, cleaning, boiling, pickling, braising, air drying, bubbling, vacuum frying, seasoning, packaging and sterilization processes. Chi Jinjun (invention name: fish scale jelly composite food and its production method, publication number CN106333277A) uses fish scale, avocado, rock sugar, lemon solution and mint as raw materials, and prepares fish scale jelly composite food through the processes of washing, boiling, filtering, drying, adding auxiliary materials, frying, draining oil, etc. Sun Zhongyi (invention name: a processing method of tilapia fish scale snack food, publication number: CN101999700A) uses tilapia as raw material, and prepares tilapia fish scale snack food through the processes of removing fishy smell, washing, drying, adding auxiliary materials and stirring, boiling, cooling, and microwave puffing. Lv Yuanping (invention name: a fish scale snack food and its production method, publication number: CN102228269A) uses fish scale as raw material, and prepares a crispy and delicious fish scale snack food with mellow taste through the steps of thawing, washing, pickling, washing, softening, frying, and oil control. Zhao Xiaohui (invention name: A leisure food made of fish scales, publication number CN103583999A) uses fish scales, grain powder and water as raw materials, and produces fish scale leisure food with health care function through stirring, puffing, cutting and granulation, cooling and transportation, rolling and tableting and baking. Luo Hong (invention name: Fish scale flake food and production process, publication number: CN1860931) uses fish scales, egg white, soybean powder, drinking water and seasoning as raw materials, and produces a healthy and delicious fish scale flake food through washing, mixing, frying and other processes. Pan Xiaoyong (invention name: A processing method for fish scale flakes, publication number: CN113017029A) uses fish scales as raw materials, and produces edible fish scale flakes through washing, pickling, cooking and seasoning processes. Zhao Gaocheng (invention name: a fish scale processing method, publication number: CN1282534) uses fish scales, eggs and flour as raw materials, and prepares healthy and delicious fish scale food through rinsing, drying, stirring, heating, frying or crushing processes.

[0005] In the above technical scheme, the instant fish scale food made by Chen Xiaolei must be boiled, which will cause the collagen in the fish scales to dissolve, resulting in a large loss of nutritional components in the product. The fish scale foods made by Chi Jinjun, Sun Zhongyi, and Lv Yuanping are all softened by steaming in a pressure cooker. The high temperature and high pressure softening process will cause a great loss of the collagen content of the fish scales, and the softened fish scales are easy to stick together, which is not conducive to subsequent processing. The fish scales made by Zhao Xiaohui need to mix the fish scales and grain powder with water, and then extrude and expand, reshape and shape them before baking. Although the nutritional value of the finished product is not lost, it is an ideal health and leisure food, but there are problems such as cumbersome process and the destruction of the original form of the raw materials. In addition, the moisture content of the finished product is between 3% and 6%, and the finished product is not crispy enough. The fish scales made by Luo Hong need to be mixed with egg white, soybean powder and drinking water to make a paste, then deep-fried at low temperature (50℃~80℃), and then seasoned and stir-fried for 3min~5min (20℃~50℃) to make fish scale flakes. The finished product is in block shape, which destroys the original form of the raw materials. In addition, the frying and stir-frying temperatures are low, and the water in the fish scales cannot be fully evaporated, so it is difficult for the product to achieve a good puffing effect, and the finished product is not crispy. The fish scale flakes made by Pan Xiaoyong do not specify the cooking method, and the marinade ingredients are complex (including Acanthopanax Cortex, Kaempferia galanga, Amomum villosum, Licorice, Angelica dahurica, Angelica sinensis, Monk Fruit, Piper serrata, Cinnamon, and Grass Buds, etc.). Although it can eliminate fishy smell and has certain physiological effects, the ingredients are too complex, which will make the fish scale flakes too seasoned and lose their original flavor, resulting in poor consumer acceptance. According to the fish scale food processing process described by Zhao Gaocheng, the raw materials must be steamed at 80℃~90℃ and then coated with flour and fried or crushed. Although crispy fish scales are produced, the steaming process will cause loss of nutrients in the finished product, and the crushing will destroy the original form of the raw materials.

[0006] In summary, in the technical scheme of preparing snack foods using fish scales as raw materials, the following problems or room for improvement are common: First, in view of the tough texture of fish scales, the process usually uses high temperature or high pressure boiling or steaming to soften the fish scales, but the collagen in the fish scales will dissolve, thereby reducing the nutritional functional characteristics of the fish scale products, and the softened fish scales are prone to adhesion, which is not conducive to subsequent processing. Second, after the fish scales are softened, extruded, puffed, fried or crushed, the original shape of the fish scales is destroyed. Third, the moisture content of the fish scale product is high, the finished product is not crispy enough, and too much seasoning is added, and the original flavor of the fish scales is lost.

[0007] Based on the above, although fish scales are rich in collagen and minerals, they are flaky, dense, and tough. It is difficult to make fish scale snacks with a crisp taste and retain the original nutrition, flavor, and shape of fish scales using ordinary processing methods. Therefore, it is necessary to propose a new process to solve the above problems and provide new ideas for the comprehensive utilization of fish scale by-products. Summary of the invention

[0008] In view of the problems or defects existing in the above-mentioned prior art, the purpose of the present invention is to provide a method for preparing crispy fish scales by medium-temperature plasticization combined with high-temperature crisping, which solves the problem that when fish scales are used as raw materials to make snack foods, the finished product tastes not crispy enough, and the original nutrition, flavor and morphology of the fish scales are difficult to retain.

[0009] To achieve the above object, the present invention provides the following technical solutions:

[0010] On the one hand, the present invention provides a method for preparing crispy fish scales by combining medium-temperature plasticization with high-temperature crisping, comprising the following steps: (1) pretreatment of raw fish scales, (2) low-salt pre-marinating to control water, (3) coating with flour, (4) frying, (5) high-temperature re-frying to control oil and coloring, (6) degreasing, and (7) seasoning, wherein the frying in step (4) comprises two process stages: fast and continuous heating medium-temperature plasticization frying and slow and continuous heating high-temperature crisping frying;

[0011] The rapid and continuous heating and medium-temperature plasticizing frying is specifically as follows: firstly, the oil temperature in the fryer, i.e., the medium-temperature frying starting temperature, is set to 150° C., and then the fish scales coated with flour are put into the fryer to start frying, and the oil temperature is controlled to rise rapidly and continuously during the frying process until the oil temperature reaches the medium-temperature frying ending temperature of 170° C., and the frying is terminated;

[0012] The slow and continuous heating high-temperature crisping frying is specifically as follows: after the rapid and continuous heating medium-temperature plasticizing frying is completed, the medium-temperature frying end temperature of 170° C. is immediately used as the high-temperature frying starting temperature to continuously perform frying in the same frying pan at the next process stage, and the oil temperature is controlled to rise slowly and continuously during the frying process until the oil temperature reaches the high-temperature frying end temperature of 190° C. to terminate the frying;

[0013] The frying time of the fast and continuous medium-temperature plasticizing frying and the slow and continuous high-temperature crisping frying is controlled to be 1:2, and the total frying time of the two process stages is controlled to be 150s to 390s;

[0014] In the frying step (4), the rapid and continuous heating and medium-temperature plasticizing frying will plasticize the collagen in the fish scales, thereby fixing the original flaky shape of the fish scales. The fish scales will then be quickly dehydrated and expanded, and a crispy texture will gradually form, compared with the conventional one-stage or multi-stage constant temperature frying. The color, texture characteristics and sensory quality of the crispy fish scales prepared by the medium-temperature plasticizing combined with the high-temperature dehydration and crispening process of the present invention are significantly improved.

[0015] As a specific technical solution, in the step (1) of pre-treating the raw fish scales, the raw fish scales include but are not limited to the scales of Wuchang fish, grass carp, black carp, crucian carp and carp.

[0016] As a specific technical solution, the specific method of pre-treating the raw fish scales in step (1) is as follows: pick out fish fins, fish bones, fish minced meat, small scales and other debris mixed in the fish scales, wash away the mud, blood stains and sticky substances on the surface of the fish scales with clean water, rinse repeatedly until the water is clear, put the cleaned fish scales into a dehydrator to remove surface moisture, and control the moisture content to 47% to 48% to ensure that the initial moisture content of the raw materials is consistent.

[0017] As a specific technical solution, the specific method of low-salt pre-marinating and water control in step (2) is as follows: based on the weight of the fish scales, add 2% to 3% of salt and 6% to 8% of cooking wine to the fish scales and stir evenly, then place them in a low temperature environment at a temperature of 0 to 5°C and marinate for 0.5 to 2.5 hours; the main purpose of marinating in traditional processes is to make the raw materials taste good and remove the fishy smell, so the improvement of the marinating process in the prior art is mainly based on the taste and fishy removal effects; and the applicant found in the study that the low-salt pre-marinating in the present invention is also related to the final water content and crispness of the crispy fish scales. Controlling reasonable pre-marinating parameters, such as the amount of salt added and the amount of cooking wine added, can effectively improve the crispness of the finally prepared crispy fish scales while ensuring that the crispy fish scales are fully tasted and fishy. In addition, marinating under low temperature conditions can effectively inhibit the growth of microorganisms; preferably, the temperature of the low temperature environment is 4°C.

[0018] As a specific technical solution, in the step (3) of coating with flour, 15% to 20% corn starch is added based on the weight of the fish scales for coating with flour; in this step, when a small amount of starch is added, the crispy fish scales are not crispy enough, and adding too much starch will cause the starch to form a shell layer on the surface of the fish scales, absorbing too much oil during the frying process, and the crispy fish scales have too high fat content and a heavy powdery texture.

[0019] As a specific technical solution, in the rapid and continuous heating medium-temperature plasticizing frying and the slow and continuous heating high-temperature crisping frying, the total frying time of the two process stages is controlled to be 270 to 330 seconds, and the material is continuously and gently stirred during the frying process to ensure that the fish scales are heated evenly to prevent the product from sticking together.

[0020] As a specific technical solution, the method for high-temperature re-frying to control oil and color in step (5) is as follows: after the fish scales that have been initially fried in step (4) are taken out and the oil is drained, they are immediately transferred to a high temperature of 190° C. for re-frying for 40 seconds to 60 seconds; the re-frying can significantly improve the color of the crispy fish scales and can also achieve the effect of controlling oil.

[0021] As a specific technical solution, the deoiling method in step (6) is: placing the fish scales fried in step (5) in a deoiling machine and centrifugally deoiling at a speed of 1250r / min for 1min to 3min. Centrifugal deoiling uses centrifugal force to throw out the oil in the finished product. The applicant found that since the crispy fish scales are thin and crispy, the centrifugal force will produce an extrusion force on the sample. Long-term extrusion will cause the product to break, which is not conducive to maintaining the original shape of the fish scales. Unlike traditional products, the deoiling time in the present invention is not the longer the better, that is, it is not necessary to use a longer deoiling time, such as a deoiling time of more than 5min to make the residual oil tend to the lowest stable value. On the contrary, when the deoiling time is controlled to 1 to 3min, although the oil content of the crispy fish scales is not at the lowest level, its shape remains intact, which can avoid the phenomenon that the crispy fish scales are broken to produce a large amount of debris and increase the greasy feeling. At this time, the product as a whole also has a good overall acceptability.

[0022] As a specific technical solution, the seasoning method in step (7) is: season the crispy fish scales that have been deoiled in step (6) while hot, and mix in an appropriate amount of instant seasoning according to preference, wherein the instant seasoning includes but is not limited to pepper and salt powder, spicy powder, cumin powder, and salted egg yolk powder, and the amount of instant seasoning added is 2% to 3% of the mass of the crispy fish scales.

[0023] On the other hand, the present invention provides a crispy fish scale, characterized in that it is obtained by any of the above-mentioned preparation methods.

[0024] Compared with the prior art, the beneficial effects of the present invention include at least:

[0025] 1) The main purpose of pickling in traditional processes is to make the raw materials flavorful and remove the fishy smell, so the improvement of the pickling process in the prior art is mainly based on the flavoring and fishy removal effects. However, the applicant unexpectedly discovered that the low-salt pre-marinating in the present invention is also related to the final water content and crispness of the crispy fish scales. Controlling reasonable pre-marinating parameters can greatly improve the crispness of the prepared crispy fish scales. Specifically, in the low-salt pre-marinating of the present invention, although salt as a water-depriving agent can cause the water inside the fish scale tissue to seep out, so that the water content of the fish scale raw material is slightly reduced, as shown in Example 1, after adding 3% salt for low-salt pre-marinating, the water content of the fish scale raw material is reduced from the initial 47.55% to 45.31%, and the reduction is only 4.7%. It can be seen that the dehydration effect of low-salt pre-marinating on the fish scale raw material is very limited. However, for the final water content and crispness of the crispy fish scales obtained after frying and de-oiling of the fish scale raw material, as shown in Example 1, after the fish scale raw material after low-salt pre-salting (salt addition 3%) is further processed into crispy fish scales, the final water content of the crispy fish scales can be reduced from 1.69% to 1.02%, and its reduction has reached 39.6%. It can be seen that low-salt pre-salting has a greater impact on the final water content of the crispy fish scales after frying, and the lower the water content of the crispy fish scales, the better its crispness. In addition, cooking wine mainly plays a role in removing fishy smell in traditional pickling technology, but the applicant has found that controlling the appropriate addition amount of cooking wine can also improve the crispness of the crispy fish scales. In summary, the present invention can not only taste and remove fishy smell to the fish scales through low-salt pre-salting, but also can greatly reduce the water content of the crispy fish scales after frying and de-oiling, so as to improve the crispness of the product.

[0026] 2) Since fish scales are flat and thin, with a dense structure and a tough texture, it is difficult for the traditional high-temperature, high-pressure steaming and softening and constant-temperature frying processes to maintain the original shape of the fish scales and ensure the crispness of the product. The present invention omits the traditional high-temperature, high-pressure steaming and softening process, which not only simplifies the processing technology of crispy fish scales, but also prevents the loss of collagen in the fish scales and avoids the destruction of the original flat and thin flaky shape of the fish scales by softening. Furthermore, the present invention replaces the traditional one-stage or multi-stage constant temperature frying by combining two process stages of rapid and continuous heating of medium-temperature plasticizing frying with slow and continuous heating of high-temperature crisping frying, that is, the pretreated fish scales are fried at medium temperature under the conditions of medium temperature frying starting temperature of 150°C and medium temperature frying ending temperature of 170°C, and the collagen structure contained therein becomes plastic, thereby finalizing the original flaky morphology of the fish scales; thereafter, the slow and continuous heating of high-temperature crisping frying stage is entered, that is, high-temperature frying is carried out slowly and continuously for a relatively long time under the conditions of high-temperature frying starting temperature of 170°C and high-temperature frying ending temperature of 190°C, during which the fish scales are rapidly dehydrated, the tissue structure expands and forms a loose and porous structure, the crispy texture of the fish scales is formed, and the original flat and flaky morphology is better maintained. The actual photos of the crispy fish scales of the present invention are shown in the figure.Figure 6 As shown, they will not stick to each other or curl completely, and the complete lamellar morphology of the fish scales is better maintained.

[0027] 3) Unlike traditional raw materials, fish scales are in a special flaky shape with a large surface area. The applicant found that when processing them into crispy fish scales, the crispness and sensory quality of the final product have a high response sensitivity to the amount of auxiliary materials added and parameter control in the processes of raw fish scale pretreatment, low-salt pre-marinating, and powder coating. In this regard, in the present invention, the applicant further ensures that the prepared crispy fish scales have good crispness and sensory acceptance by reasonably optimizing and accurately controlling the parameters in each process, including controlling the moisture content of the fish scales to 47% to 48% in the raw fish scale pretreatment, controlling the amount of salt and cooking wine added in the low-salt pre-marinating, controlling the amount of starch added in the powder coating, and controlling the degreasing time. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The effect of marinating time on the moisture content (a) and fat content (b) of crispy fish scales;

[0029] Figure 2 To investigate the effect of pickling time on the salt content of crispy fish scales;

[0030] Figure 3 The effect of re-frying time on the moisture content (a) and fat content (b) of crispy fish scales;

[0031] Figure 4 The effect of de-oiling time on the moisture content (a) and fat content (b) of crispy fish scales;

[0032] Figure 5 For crispy fish scales organizational chart ;

[0033] Figure 6 This is the finished photo of the crispy fish scales. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail in conjunction with the following embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0035] The determination methods of the indicators involved in the following embodiments of the present invention are as follows:

[0036] Moisture content: Determined by the direct drying method in accordance with GB5009.3-2016 “Determination of moisture in food”.

[0037] Fat content: Determined by Soxhlet extraction method in accordance with GB5009.6-2016 “Determination of Fat in Foods”.

[0038] Protein content: refer to the Kjeldahl nitrogen determination method in GB5009.5-2016 "Determination of protein in food".

[0039] Ash content: refer to the determination of total ash in food in GB5009.4-2016 "Determination of ash in food".

[0040] Solid content: The solid content is the difference between the total mass and the water content.

[0041] Salt content: Determined by direct titration method according to SC / T 3011-2001 “Determination of Salt Content in Aquatic Products”.

[0042] Chroma: Measured by a colorimeter. Using the instrument white board color as the standard, measure the lightness index L*, a*, and b* values ​​of the product in turn.

[0043] Crispness: The TA-XT Plus texture analyzer was used to measure the structural properties of the crispy fish scales to obtain parameters such as crispness and hardness of the crispy fish scales. The crispy fish scales were placed on the sample table, the test probe was P / 36R, the pre-test speed was 5.0mm / s, the test speed was 0.5mm / s, the post-test speed was 10.0mm / s, the test compression ratio was 60%, and the trigger point load was 5.0g.

[0044] Sensory evaluation: A sensory evaluation team of 8 food graduate students was formed and professional training was conducted. The crispy fish scales were scored based on their shape, color, smell, taste, and greasiness. The scoring criteria are shown in the table below. Each item has a full score of 10 points, and the overall acceptability is the sum of the product of each item score and the corresponding weight.

[0045] Microstructure: Cut the crispy fish scales into thin slices of 2mm×2mm×1mm, stick them on the sample stage of a scanning electron microscope, spray gold using an automatic gold sprayer, and observe the structure of the crispy fish scales using a scanning electron microscope.

[0046] Table 1 Sensory scoring criteria for crispy fish scales

[0047]

[0048] Example 1

[0049] A method for preparing crispy fish scales by medium-temperature plasticization combined with high-temperature crisping, comprising the following steps:

[0050] (1) Pretreatment of raw fish scales: picking out fish fins, fish bones, fish scraps, small scales and other debris mixed in the raw fish scales, washing the mud, blood stains and sticky substances on the surface of the fish scales with clean water, repeatedly rinsing until the water is clear, and placing the cleaned fish scales in a dehydrator to remove surface moisture; the raw fish scales include but are not limited to the scales of Wuchang fish, grass carp, black carp, crucian carp and carp;

[0051] (2) Low-salt pre-marinating and water control: Based on the weight of fish scales, add 2% to 3% salt and 6% to 8% cooking wine to the fish scales and stir evenly, then marinate at a low temperature of 0 to 5°C for 0.5 to 2.5 hours;

[0052] (3) Coating with flour: Based on the weight of the fish scales, add 15% to 20% corn starch for coating;

[0053] (4) Frying: This includes two process stages: fast and continuous heating at medium temperature for plasticization frying and slow and continuous heating at high temperature for crisping frying;

[0054] The rapid and continuous heating and medium-temperature plasticizing frying is specifically as follows: firstly, the oil temperature in the fryer, i.e., the medium-temperature frying starting temperature, is set to 150° C., and then the fish scales coated with flour are put into the fryer to start frying, and during the frying process, the oil temperature is controlled to rise rapidly and continuously until the oil temperature reaches the medium-temperature frying ending temperature of 170° C., and the frying time of this process stage is controlled to be 90s to 110s;

[0055] The slow and continuous heating high-temperature crisping frying is specifically as follows: after the rapid and continuous heating medium-temperature plasticizing frying is completed, the medium-temperature frying end temperature of 170° C. is immediately used as the high-temperature frying starting temperature to continuously perform frying in the same frying pan at the next process stage, and the oil temperature is controlled to rise slowly and continuously during the frying process until the oil temperature reaches the high-temperature frying end temperature of 190° C. to terminate the frying;

[0056] The frying time of the fast and continuous medium-temperature plasticizing frying and the slow and continuous high-temperature crisping frying is controlled to be 1:2, and the total frying time of the two process stages is controlled to be 150s to 390s; the material is constantly and gently stirred during the frying process to make the fish scales heated evenly and prevent the product from sticking together;

[0057] (5) High-temperature re-frying to control oil and coloring: After the fish scales that have been initially fried in step (4) are taken out and the oil is drained, they are immediately re-fried at 190° C. for 40 to 60 seconds;

[0058] (6) De-oiling: The fish scales re-fried in step (5) are placed in a de-oiling machine and centrifuged at a speed of 1250 r / min for de-oiling for 1 min to 3 min.

[0059] (7) Seasoning: Season the crispy fish scales that have been de-oiled in step (6) while they are still hot, and add an appropriate amount of instant seasoning according to preference. The instant seasoning includes but is not limited to pepper and salt powder, spicy powder, cumin powder, and salted egg yolk powder. The amount of instant seasoning added is 2% to 3% of the mass of the crispy fish scales.

[0060] Example 2

[0061] The method of the present invention is to study the amount of salt added, the amount of cooking wine added and the pickling time for low-salt pre-pickle.

[0062] 1. Study on the amount of salt added in low-salt pre-salting

[0063] 1. Experimental methods

[0064] The method of the present invention is adopted to prepare crispy fish scales, wherein, based on the weight of the fish scales, the amount of salt added in the low-salt pre-salting water is controlled to be 0%, 0.5%, 1.0%, 1.5%, 2.0%, 2.5%, and 3.0%, respectively, and specifically comprises the following steps:

[0065] (1) Pretreatment of raw fish scales: After selecting and cleaning the fish scales, use a dehydrator to dehydrate for 5 minutes;

[0066] (2) Low-salt pre-marinating and water control: different proportions of salt (0%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%) were added to the fish scales, and 4% cooking wine was added to each portion to remove the fishy smell, and the fish scales were marinated at 4°C for 0.5 h;

[0067] (3) Coating with flour: Add 20% corn starch to the pre-marinated fish scales and mix well;

[0068] (4) Frying: This includes two process stages: fast and continuous heating at medium temperature for plasticization frying and slow and continuous heating at high temperature for crisping frying;

[0069] The rapid and continuous heating medium-temperature plasticizing frying is specifically as follows: firstly, the oil temperature in the fryer, i.e., the medium-temperature frying starting temperature, is set to 150° C., and then the fish scales coated with flour are put into the fryer to start frying, and during the frying process, the oil temperature is controlled to be rapidly and continuously raised until the oil temperature reaches the medium-temperature frying ending temperature of 170° C., and the frying time of this process stage is controlled to be 90 seconds; during the frying process, the material is continuously and gently stirred to heat the fish scales evenly and prevent the product from sticking together;

[0070] The slow and continuous heating high-temperature crisping frying is specifically as follows: after the rapid and continuous heating medium-temperature plasticizing frying is completed, the medium-temperature frying end temperature of 170° C. is immediately used as the high-temperature frying starting temperature to continuously perform frying in the same fryer at the next process stage, and the oil temperature is controlled to rise slowly and continuously during the frying process until the oil temperature reaches the high-temperature frying end temperature of 190° C. to terminate the frying, and the frying time of this process stage is controlled to be 180 seconds; the material is continuously and gently stirred during the frying process to heat the fish scales evenly and prevent the product from sticking together;

[0071] (5) High-temperature re-frying to control oil and color: After the fish scales are fried for 30 seconds, they are immediately re-fried at 190°C for 40 seconds;

[0072] (6) De-oiling: After high-temperature re-frying, the fish scales are immediately placed in a de-oiling machine at a speed of 1250 r / min for de-oiling for 5 min.

[0073] The moisture content of fish scales, basic nutritional components, texture characteristics, color, saltiness and sensory scores of crispy fish scales were tested under the different salt addition amounts mentioned above.

[0074] 2. Experimental results and analysis

[0075] 2.1 Effect of different salt addition amounts on the moisture content of fish scales

[0076] Table 2 Effect of salt addition on the moisture content of fish scales

[0077] Salt addition amount (%) Moisture content (%) 0 <![CDATA[47.55±1.05 a ]]> 0.5 <![CDATA[47.07±0.45 ab ]]> 1.0 <![CDATA[47.26±0.33 a ]]> 1.5 <![CDATA[46.51±0.44 abc ]]> 2.0 <![CDATA[45.98±0.74 bcd ]]> 2.5 <![CDATA[45.82±0.55 cd ]]> 3.0 <![CDATA[45.31±0.59 d ]]>

[0078] Note: Different lowercase letters indicate significant differences (p<0.05).

[0079] As shown in Table 2, with the increase of salt addition, the water content of fish scales gradually decreased after pickling due to the osmotic effect of salt, which caused the fish scales to lose water (p<0.05). However, the water content of fish scales pickled without salt was 47.55%, while the water content of fish scales pickled with 3% salt was 45.31%, and the decrease was only 4.7%. It can be seen that low-salt pre-salting has a very limited dehydration effect on fish scale raw materials.

[0080] 2.2 Determination of basic nutritional components of crispy fish scales with different salt addition amounts

[0081] Table 3 Effect of salt addition on basic nutritional components of crispy fish scales

[0082]

[0083] Note: Different lowercase letters indicate significant differences (p<0.05).

[0084] As shown in Table 3, the amount of salt added has a significant effect on the moisture content, fat content, ash content, and soluble solid content of the crispy fish scales (p<0.05). With the increase in the amount of salt added, the moisture content of the product is significantly reduced, the fat content shows a trend of first increasing and then decreasing, and the ash and soluble solid content gradually increase. When the amount of salt added is 2% to 3%, the fat content of the product is relatively low, between 17.64% and 18.88%. The applicant found that after the fish scale raw material after low-salt pre-salting (salt addition 3%) is further processed into crispy fish scales, the final moisture content of the crispy fish scales can be reduced from 1.69% to 1.02%, and the reduction rate reaches 39.6%. It can be seen that low-salt pre-salting has a greater effect on the final moisture content of the crispy fish scales after frying.

[0085] 2.3 Effects of different salt addition amounts on the texture characteristics of crispy fish scales

[0086] Table 4 Effect of salt addition on the texture characteristics of crispy fish scales

[0087]

[0088] Note: Different lowercase letters indicate significant differences (p<0.05).

[0089] As shown in Table 4, the amount of salt added has a significant effect on the crispness, brittleness, and overall crispness of the crispy fish scales (p<0.05). The crispness, brittleness, and crispness of the samples all increase with the increase in the amount of salt added. When the amount of salt added is between 2% and 3%, the crispness of the product is at an optimal level. Combining the data and analysis of Tables 2 and 3, it can be seen that although the initial water content of the raw fish scales is reduced by adding salt, the reduction is small, while the final water content of the crispy fish scales obtained after frying is greatly reduced. Since the water content of the product is inversely proportional to its crispness, that is, the lower the water content, the better the crispness of the product, the crispness of the crispy fish scales increases with the increase in the amount of salt added in the pre-marinating stage. The reason for the above results may be that the moisture in the raw fish scales that is reduced by the penetration of salt during the pre-marinating stage may be the moisture that is difficult to remove in the subsequent frying. Therefore, the amount of salt added in the pre-marinating stage can be adjusted to control the moisture content of the fish scales after frying, thereby improving the crispness of the product.

[0090] 2.4 Effect of different salt addition amounts on the color of crispy fish scales

[0091] Table 5 Effect of salt addition on the chromaticity of crispy fish scales

[0092]

[0093]

[0094] Note: Different lowercase letters indicate significant differences (p<0.05).

[0095] Chroma is one of the important indicators for evaluating food quality and directly affects consumers’ purchasing desire. * represents brightness, a* is the red and green value, b * Represents the yellow-blue value, b * The larger the value, the yellower the color of the finished product, and W is the whiteness value. As shown in Table 5, the amount of salt added has a significant effect on the a* and b* values ​​of the crispy fish scales (p<0.05). With the increase of the amount of salt added, the a* value of the product generally shows a trend of gradual decrease, and the b* value shows a trend of continuous increase. When the amount of salt added is 3%, the a* of the crispy fish scales reaches the minimum value and the b* reaches the maximum value.

[0096] 2.5 Effect of different salt addition amounts on the salt content of crispy fish scales

[0097] Table 6 Effect of salt addition on salt content of crispy fish scales

[0098]

[0099] Note: Different lowercase letters indicate significant differences (p<0.05).

[0100] Excessive salt intake will increase the incidence of many diseases. The "Dietary Guidelines for Chinese Residents (2022)" recommends that each person consume no more than 5 grams of salt per day. As shown in Table 6, the salt content of the product increases significantly with the increase in the amount of salt added (p<0.05). When the salt addition is 2%, the salt content of the product is 1.65g / 100g<2g / 100g, which is still a low-salt food; when the salt addition is 2.5%, the salt content of the product is 2.23g / 100g>2g / 100g, which is no longer a low-salt food.

[0101] 2.6 Effects of different salt addition amounts on sensory scores of crispy fish scales

[0102] Table 7 Effect of salt addition on sensory scores of crispy fish scales

[0103]

[0104] Note: Different lowercase letters indicate significant differences (p<0.05).

[0105] Table 7 shows the effect of salt addition on the sensory quality of crispy fish scales. As can be seen from the table, the amount of salt added has a significant effect on the color, taste, greasiness, overall acceptability, and aroma of crispy fish scales (p<0.05), but has no significant effect on its morphology (p>0.05). With the increase of salt addition, the taste and overall acceptability of the product first increase and then decrease; among them, the color, aroma, and greasiness show a trend of continuous increase. When the salt addition is between 2% and 3%, the overall acceptability of the product is at a high level.

[0106] 2. Research on the amount of cooking wine added for low-salt pre-marination

[0107] 1. Experimental methods

[0108] The method of the present invention is adopted to prepare crispy fish scales, wherein, based on the weight of the fish scales, the amount of cooking wine added in the low-salt pre-marinating is controlled to be 0%, 2%, 4%, 6%, 8%, and 10%, respectively, and specifically comprises the following steps:

[0109] (1) Pretreatment of raw fish scales: After selecting and cleaning the fish scales, use a dehydrator to dehydrate for 5 minutes;

[0110] (2) Low-salt pre-marinating and water control: add 2% salt and 0%, 2%, 4%, 6%, 8%, and 10% cooking wine to the fish scales and marinate at 4°C for 0.5 h;

[0111] (3) Coating with flour: Add 15% corn starch to the pre-marinated fish scales and mix well;

[0112] (4) Frying: This includes two process stages: fast and continuous heating at medium temperature for plasticization frying and slow and continuous heating at high temperature for crisping frying;

[0113] The rapid and continuous heating medium-temperature plasticizing frying is specifically as follows: firstly, the oil temperature in the fryer, i.e., the medium-temperature frying starting temperature, is set to 150° C., and then the fish scales coated with flour are put into the fryer to start frying, and during the frying process, the oil temperature is controlled to be rapidly and continuously raised until the oil temperature reaches the medium-temperature frying ending temperature of 170° C., and the frying time of this process stage is controlled to be 90 seconds; during the frying process, the material is continuously and gently stirred to heat the fish scales evenly and prevent the product from sticking together;

[0114] The slow and continuous heating high-temperature crisping frying is specifically as follows: after the rapid and continuous heating medium-temperature plasticizing frying is completed, the medium-temperature frying end temperature of 170° C. is immediately used as the high-temperature frying starting temperature to continuously perform frying in the same fryer at the next process stage, and the oil temperature is controlled to rise slowly and continuously during the frying process until the oil temperature reaches the high-temperature frying end temperature of 190° C. to terminate the frying, and the frying time of this process stage is controlled to be 180 seconds; the material is continuously and gently stirred during the frying process to heat the fish scales evenly and prevent the product from sticking together;

[0115] (5) High-temperature re-frying to control oil and color: After the fish scales are fried for 30 seconds, they are immediately re-fried at 190°C for 40 seconds;

[0116] (6) De-oiling: After high-temperature re-frying, the fish scales are immediately placed in a de-oiling machine at a speed of 1250 r / min for de-oiling for 5 min.

[0117] The basic nutritional components, texture characteristics, color, and sensory scores of crispy fish scales were tested under the different amounts of cooking wine added.

[0118] 2. Experimental results and analysis

[0119] 2.1 Determination of basic nutritional components of crispy fish scales with different amounts of cooking wine added

[0120] Table 8 Effect of cooking wine addition on basic nutritional components of crispy fish scales

[0121]

[0122] Note: Different lowercase letters indicate significant differences (p<0.05).

[0123] It can be seen from Table 8 that with the increase in the amount of cooking wine added, the solid content of the crispy fish scales first decreases and then increases; the fat content generally decreases; the protein content gradually increases; and the moisture content of the crispy fish scales first increases and then decreases. When the amount of cooking wine added is 6% to 8%, the moisture content of the crispy fish scales is at a relatively low level, at 0.97% to 1.1%.

[0124] 2.2 Effects of different amounts of cooking wine on the texture characteristics of crispy fish scales

[0125] Table 9 Effect of cooking wine addition on the texture characteristics of crispy fish scales

[0126]

[0127] Note: Different lowercase letters indicate significant differences (p<0.05).

[0128] It can be seen from Table 9 that the crispness and crunchiness of the crispy fish scales first increase and then decrease with the increase of the amount of cooking wine added. When the amount of cooking wine added is 6% to 8%, the crispness and crunchiness of the crispy fish scales are at an optimal level. The reasons may be that, first, adding an appropriate amount of cooking wine can increase the adhesion between the fish scales and starch, thereby improving the crispness of the product; second, as shown in the data in Table 8, when the amount of cooking wine added is 6% to 8%, the moisture content of the finally prepared crispy fish scales is at a lower level, which is conducive to maintaining the crispness of the crispy fish scales.

[0129] 2.3 Effect of different amounts of cooking wine on the color of crispy fish scales

[0130] Table 10 Effect of cooking wine addition on the chromaticity of crispy fish scales

[0131]

[0132]

[0133] Note: Different lowercase letters indicate significant differences (p<0.05).

[0134] As shown in Table 10, the amount of cooking wine added has a significant effect on the L* (brightness value), a* (red-green value), b* (yellow-blue value), and W (whiteness value) of the product. Among them, the red-green value of the product decreases with the increase of the amount of cooking wine added, and the yellow-blue value increases with the increase of the amount of cooking wine added; the brightness and whiteness show a trend of first decreasing and then increasing. When the amount of cooking wine added is 6%, the brightness and whiteness values ​​of the crispy fish scales reach the maximum, which are 63.76 and 62.88 respectively.

[0135] 2.4 Effect of different amounts of cooking wine added on sensory scores of crispy fish scales

[0136] Table 11 Effect of cooking wine addition on sensory scores of crispy fish scales

[0137]

[0138] Note: Different lowercase letters indicate significant differences (p<0.05).

[0139] As shown in Table 11, the amount of cooking wine added has a significant effect on the color, aroma, taste, and overall acceptability of crispy fish scales (p<0.05). As the amount of cooking wine added increases, the smell score of the product shows a continuous upward trend. This is because cooking wine has a deodorizing effect and can effectively remove the fishy smell of fish scales. When the amount of cooking wine added is 6%, the smell score of the product reaches a maximum of 8.56; as the amount of cooking wine added increases, the taste and overall acceptability of the product also show a continuous increasing trend. This is because adding an appropriate amount of cooking wine can increase the adhesion between the raw materials and starch, thereby improving the taste of the product. When the amount of cooking wine added is 6% to 8%, the taste and overall acceptability scores of the product are at a high level.

[0140] 3. Study on the pickling time of low-salt pre-pickle

[0141] 1. Experimental methods

[0142] The method of the present invention is adopted to prepare crispy fish scales, wherein, based on the weight of the fish scales, the pickling time is controlled to be 0h, 0.5h, 1.0h, 1.5h, 2.0h, 2.5h, and 3.0h, respectively, and specifically comprises the following steps:

[0143] (1) Pretreatment of raw fish scales: After selecting and cleaning the fish scales, use a dehydrator to dehydrate for 5 minutes;

[0144] (2) Low-salt pre-marinating and water control: add 2% salt and 6% cooking wine to the fish scales and marinate at 4°C for 0 h, 0.5 h, 1.0 h, 1.5 h, 2.0 h, 2.5 h, and 3.0 h;

[0145] (3) Coating with flour: Add 15% corn starch to the pre-marinated fish scales and mix well;

[0146] (4) Frying: This includes two process stages: fast and continuous heating at medium temperature for plasticization frying and slow and continuous heating at high temperature for crisping frying;

[0147] The rapid and continuous heating medium-temperature plasticizing frying is specifically as follows: firstly, the oil temperature in the fryer, i.e., the medium-temperature frying starting temperature, is set to 150° C., and then the fish scales coated with flour are put into the fryer to start frying, and during the frying process, the oil temperature is controlled to be rapidly and continuously raised until the oil temperature reaches the medium-temperature frying ending temperature of 170° C., and the frying time of this process stage is controlled to be 90 seconds; during the frying process, the material is continuously and gently stirred to heat the fish scales evenly and prevent the product from sticking together;

[0148] The slow and continuous heating high-temperature crisping frying is specifically as follows: after the rapid and continuous heating medium-temperature plasticizing frying is completed, the medium-temperature frying end temperature of 170° C. is immediately used as the high-temperature frying starting temperature to continuously perform frying in the same fryer at the next process stage, and the oil temperature is controlled to rise slowly and continuously during the frying process until the oil temperature reaches the high-temperature frying end temperature of 190° C. to terminate the frying, and the frying time of this process stage is controlled to be 180 seconds; the material is continuously and gently stirred during the frying process to heat the fish scales evenly and prevent the product from sticking together;

[0149] (6) High-temperature re-frying to control oil and color: After the fish scales are fried for 30 seconds, they are immediately re-fried at 190°C for 40 seconds;

[0150] (7) De-oiling: After high-temperature re-frying, the fish scales are immediately placed in a de-oiling machine at a speed of 1250 r / min for de-oiling for 5 minutes.

[0151] The moisture content, fat content and salt content of the crispy fish scales were tested under the different marinating times mentioned above.

[0152] 2. Experimental results and analysis

[0153] 2.1 Effect of marinating time on moisture and fat content of crispy fish scales

[0154] The results of the effects of marinating time on the moisture and fat content of crispy fish scales are as follows Figure 1 As shown. Figure 1 It can be seen that the pickling time has a significant effect on the moisture content and fat content of crispy fish scales (p<0.05). Among them, the moisture content of crispy fish scales shows a trend of first decreasing and then increasing with the extension of pickling time. The reason for this phenomenon is that the osmotic effect of salt causes the fish scales to lose water. When the water loss reaches equilibrium, it will absorb part of the lost water to increase the moisture content; the fat content of crispy fish scales shows a trend of first increasing and then decreasing with the extension of pickling time. This is because the water in the fish scales evaporates during the frying process to form holes, and the oil enters the food through the holes. Therefore, the more water evaporates during the frying process, the lower the moisture content of the product and the higher the oil content. Since the crispness of crispy fish scales is related to its water content, and crispy fish scales are rich in a certain amount of oil, which can give them flavor and good taste, considering the above factors, it is more appropriate to choose a pickling time of 0.5 to 2.5 hours, which can keep the moisture content and fat content of crispy fish scales at an ideal level.

[0155] 2.2 Effect of salt content on pickling time of crispy fish scales

[0156] The results of the effects of salt on the pickling time and crispy fish scales are as follows Figure 2 shown. Figure 2 The effect of pickling time on the salt content of crispy fish scales. Figure 2It can be seen that the pickling time has a significant effect on the salt content of crispy fish scales (p<0.05), and the salt content of the product shows a trend of first increasing and then decreasing with the extension of the pickling time. The reason for this phenomenon is that as the pickling time increases, the osmotic pressure between the fish scales and the salt becomes greater and greater, and the salt content of the crispy fish scales also increases; when the pickling time is too long, the salt content in the fish scales reaches a certain level and reverse osmosis is formed, causing the salt content to decrease. During the pickling process, the salt in the crispy fish scales can help the crispy fish scales to effectively absorb the flavor. When the pickling time is 0.5-2.5h, the salt content in the crispy fish scales is higher, which is conducive to the removal of fishy smell and the absorption of flavor of the crispy fish scales.

[0157] IV. Conclusion

[0158] In the traditional process of processing fish scales into snack foods, the main purpose of pickling is to make the raw materials tasty and remove the fishy smell, so the improvement of the pickling process is mainly based on the taste and fishy removal effects. However, in the present invention, the applicant unexpectedly discovered that low-salt pre-marinating is also related to the final water content and crispness of the crispy fish scales, and controlling reasonable pre-marinating parameters can greatly improve the crispness of the prepared crispy fish scales. Based on the above experimental data, when the amount of salt added in the low-salt pre-marinating is controlled to 2% to 3%, the amount of cooking wine added is controlled to 6% to 8%, and the marinating time is controlled to 0.5 to 2.5h, the crispness of the finally prepared crispy fish scales can be effectively improved while ensuring that the crispy fish scales are fully flavored and fishy.

[0159] Example 3

[0160] Research on the amount of starch added during flour coating in the method of the present invention.

[0161] 1. Experimental methods

[0162] The method of the present invention is adopted to prepare crispy fish scales, wherein, based on the weight of the fish scales, the amount of starch added in the powder coating process is controlled to be 0%, 5%, 10%, 15%, 20%, and 25%, respectively, and specifically comprises the following steps:

[0163] (1) Pretreatment of raw fish scales: After selecting and cleaning the fish scales, use a dehydrator to dehydrate for 5 minutes;

[0164] (2) Low-salt pre-marinating and water control: add 2% salt and 4% cooking wine to the fish scales and marinate at 4°C for 0.5 h;

[0165] (3) Coating with flour: add 0%, 5%, 10%, 15%, 20%, 25% corn starch to the pre-marinated fish scales and mix well;

[0166] (4) Frying: This includes two process stages: fast and continuous heating at medium temperature for plasticization frying and slow and continuous heating at high temperature for crisping frying;

[0167] The rapid and continuous heating medium-temperature plasticizing frying is specifically as follows: firstly, the oil temperature in the fryer, i.e., the medium-temperature frying starting temperature, is set to 150° C., and then the fish scales coated with flour are put into the fryer to start frying, and during the frying process, the oil temperature is controlled to be rapidly and continuously raised until the oil temperature reaches the medium-temperature frying ending temperature of 170° C., and the frying time of this process stage is controlled to be 90 seconds; during the frying process, the material is continuously and gently stirred to heat the fish scales evenly and prevent the product from sticking together;

[0168] The slow and continuous heating high-temperature crisping frying is specifically as follows: after the rapid and continuous heating medium-temperature plasticizing frying is completed, the medium-temperature frying end temperature of 170° C. is immediately used as the high-temperature frying starting temperature to continuously perform frying in the same fryer at the next process stage, and the oil temperature is controlled to rise slowly and continuously during the frying process until the oil temperature reaches the high-temperature frying end temperature of 190° C. to terminate the frying, and the frying time of this process stage is controlled to be 180 seconds; the material is continuously and gently stirred during the frying process to heat the fish scales evenly and prevent the product from sticking together;

[0169] (6) High-temperature re-frying to control oil and color: After the fish scales are fried for 30 seconds, they are immediately re-fried at 190°C for 40 seconds;

[0170] (7) De-oiling: After high-temperature re-frying, the fish scales are immediately placed in a de-oiling machine at a speed of 1250 r / min for de-oiling for 5 minutes.

[0171] The texture characteristics, color, salt content and sensory score of crispy fish scales were tested under the different starch addition amounts mentioned above.

[0172] 2. Experimental results and analysis

[0173] 2.1 Effect of different starch addition amounts on the texture characteristics of crispy fish scales

[0174] Table 12 Effect of starch addition on the texture characteristics of crispy fish scales

[0175] Starch addition amount (%) Crispness(pcs) Brittleness Crispness (pcs) Hardness(g) 0 <![CDATA[5.13±0.83 b ]]> <![CDATA[4.63±0.92 c ]]> <![CDATA[9.75±1.28 c ]]> <![CDATA[589.88±80.07 a ]]> 5 <![CDATA[5.63±1.41 b ]]> <![CDATA[4.38±1.19 c ]]> <![CDATA[10.00±0.93 c ]]> <![CDATA[442.89±120.99 bc ]]> 10 <![CDATA[6.25±1.67 b ]]> <![CDATA[6.50±1.41 b ]]> <![CDATA[12.75±1.28 b ]]> <![CDATA[499.16±127.72 ab ]]> 15 <![CDATA[10.25±2.87 a ]]> <![CDATA[6.63±1.69 b ]]> <![CDATA[16.88±2.95 a ]]> <![CDATA[375.83±112.39 bc ]]> 20 <![CDATA[10.13±2.30 a ]]> <![CDATA[8.25±2.12 a ]]> <![CDATA[18.38±2.26 a ]]> <![CDATA[557.89±124.68 ab ]]> 25 <![CDATA[9.75±1.91 a ]]> <![CDATA[8.38±1.77 a ]]> <![CDATA[18.13±2.70 a ]]> <![CDATA[464.24±94.52 c ]]>

[0176] Note: Different lowercase letters indicate significant differences (p<0.05).

[0177] Texture properties are important quality evaluation indicators of crispy foods, including crispness, brittleness, overall crispness and hardness. Table 12 shows the effect of starch addition on the texture properties of crispy fish scales. The crispness, brittleness and overall crispness of the product increase with the increase of starch addition. When 15% to 20% starch is added, the crispness value of the product is at a higher level.

[0178] 2.2 Effect of different starch addition amounts on the color of crispy fish scales

[0179] Table 13 Effect of starch addition on the chromaticity of crispy fish scales

[0180]

[0181]

[0182] Note: Different lowercase letters indicate significant differences (p<0.05).

[0183] It can be seen from Table 13 that with the increase of starch addition, the b *( The yellow-blue value) shows a continuous upward trend. This is because during the frying process, the starch denatures at high temperature and undergoes Maillard reaction, caramelization and other reactions, making the sample appear golden in color.

[0184] 2.3 Effect of different starch addition amounts on sensory scores of crispy fish scales

[0185] Table 14 Effect of starch addition on sensory scores of crispy fish scales

[0186]

[0187] Note: Different lowercase letters indicate significant differences (p<0.05).

[0188] Adding an appropriate amount of starch to the raw materials can improve the color and taste of the crispy fish scales. As shown in Table 14, with the increase in the amount of starch added, the color and taste of the product tend to gradually increase, but the greasiness tends to gradually decrease. When the amount of starch added is 15% to 20%, the overall acceptability of the product is at a high level.

[0189] 3. Conclusion

[0190] Since fish scales are in a special flaky shape with a large surface area, too little starch may not be able to evenly coat the surface of the fish scales, thus failing to achieve the effect of coating. When the starch addition amount is controlled at 15% to 20%, the crispy and overall acceptability of the crispy fish scales are good.

[0191] Example 4

[0192] The preferred determination of frying method and frying temperature in the method of the present invention.

[0193] 1. Experimental methods

[0194] The method of the present invention is used to prepare crispy fish scales, wherein the frying is carried out by constant temperature frying and medium temperature plasticization combined with high temperature crisping frying, and specifically comprises the following steps:

[0195] (1) Pretreatment of raw fish scales: After selecting and cleaning the fish scales, use a dehydrator to dehydrate for 5 minutes;

[0196] (2) Low-salt pre-marinating and water control: Add 2% salt and 6% cooking wine to the fish scales and marinate at 4°C for 0.5 h;

[0197] (4) Coating with flour: Add 15% corn starch to the pre-marinated fish scales and mix well;

[0198] (5) Frying: Frying is performed in the following two ways:

[0199] The method of the present invention adopts fast continuous heating medium temperature plastic frying combined with slow continuous heating high temperature crisp frying, wherein the frying time of the fast continuous heating medium temperature plastic frying stage is controlled to be 90 seconds, the time of the slow continuous heating high temperature crisp frying is controlled to be 180 seconds, the total frying time is 270 seconds, and the starting point and ending temperatures of the frying process are specifically set as shown in the following table:

[0200]

[0201] Conventional method: constant temperature frying and two-stage frying are adopted. The frying temperatures of the constant temperature frying are respectively set to the end temperature of the medium temperature frying of the present invention, i.e., 140°C, 150°C, 160°C, 170°C, 180°C, and the frying time is 270s; the frying temperature of the first stage of the two-stage frying is 150°C, the frying temperature of the second stage is 170°C, the frying time of the two stages is 1:2, and the total frying time is 270s. The specific settings are as shown in the following table:

[0202] Group Frying temperature / ℃ 6 140 7 150 8 160 9 170 10 180 11 The first stage is 150℃, the second stage is 170℃

[0203] (6) High-temperature re-frying to control oil and color: After the fish scales are fried for 30 seconds, they are immediately re-fried at 190°C for 40 seconds;

[0204] (7) De-oiling: After high-temperature re-frying, the fish scales are immediately placed in a de-oiling machine at a speed of 1250 r / min for de-oiling for 5 minutes.

[0205] The temperature rise curve of the crispy fish scales under the above different frying methods, the basic nutritional components, texture characteristics, color, salt and sensory scores of the crispy fish scales were tested.

[0206] 2. Experimental results and analysis

[0207] 2.1 Effects of frying method and frying temperature on basic nutritional components of crispy fish scales

[0208] Table 15 Effects of frying method and temperature on basic nutritional components of crispy fish scales

[0209]

[0210]

[0211] Note: Different lowercase letters indicate significant differences (p<0.05).

[0212] As shown in Table 15, the frying temperature has a significant effect on the moisture content, solid content and fat content of the crispy fish scales (p<0.05), and has no significant effect on its protein content and ash content (p>0.05). Among them, the moisture content of the products processed by the method of the present invention and constant temperature frying decreases with the increase of frying temperature, and the solid content increases with the increase of frying temperature. The fat content of the products made by the method of the present invention shows a trend of first increasing, then decreasing and then increasing with the increase of frying temperature. Among them, when the medium temperature frying starting temperature, medium temperature frying ending temperature, high temperature frying starting temperature and high temperature frying ending temperature of group 4 are 150℃, 170℃, 170℃ and 190℃ respectively, the fat content of the crispy fish scales is the lowest at 18.14%; the fat content of the products made by constant temperature frying increases with the increase of frying temperature, and the oil content of the crispy fish scales made by constant temperature frying is generally higher than that of medium temperature plasticization combined with high temperature crisping fried products.

[0213] 2.2 Effects of frying method and temperature on the texture characteristics of crispy fish scales

[0214] Table 16 Effects of frying method and temperature on the texture characteristics of crispy fish scales

[0215]

[0216] Note: Different lowercase letters indicate significant differences (p<0.05).

[0217] As shown in Table 16, the frying temperature has a significant effect on the crispness, brittleness, crispness and hardness of the crispy fish scales (p<0.05). The crispness, brittleness and crispness of the products processed by the method of the present invention and the constant temperature frying increase with the increase of the frying temperature, and the hardness gradually decreases with the increase of the frying temperature. Among them, when the medium-temperature frying starting temperature, the medium-temperature frying ending temperature, the high-temperature frying starting temperature and the high-temperature frying ending temperature of the group 4 of the method of the present invention are 150°C, 170°C, 170°C and 190°C respectively, the crispness, brittleness and crispness of the products produced therefrom all reach the maximum values, which are 13.13, 8.88 and 22.00 respectively, and at this time, the crispy fish scales form a loose and porous structure (see Figure 5 ). In addition, the crispness, brittleness and overall crispness of the products of constant temperature frying and two-stage frying are lower than those of the method of the present invention.

[0218] 2.3 Effects of frying method and temperature on the color of crispy fish scales

[0219] Table 17 Effect of frying method and temperature on the color of crispy fish scales

[0220]

[0221] Note: Different lowercase letters indicate significant differences (p<0.05).

[0222] As shown in Table 17, the frying temperature has a significant effect on the redness and yellowness of the crispy fish scales (p<0.05). The redness of the products processed by the method of the present invention and constant temperature frying decreases with the increase of frying temperature, and the yellowness increases with the increase of frying temperature. Among them, when the medium temperature frying starting temperature, medium temperature frying ending temperature, high temperature frying starting temperature, and high temperature frying ending temperature of group 4 of the inventive method are 150°C, 170°C, 170°C, and 190°C respectively, the yellowness value of the product reaches a maximum of 11.51. Under the same processing temperature, the yellowness value of the crispy fish scales prepared by the method of the present invention is generally higher than that of constant temperature frying and two-stage frying.

[0223] 2.4 Effects of frying method and temperature on sensory quality of crispy fish scales

[0224] Table 18 Effect of frying method and temperature on sensory scores of crispy fish scales

[0225]

[0226]

[0227] Note: Different lowercase letters indicate significant differences (p<0.05).

[0228] As shown in Table 18, the frying temperature has a significant effect on the color, smell, taste, greasy feeling and overall acceptability of the crispy fish scales (p<0.05). On the whole, the organoleptic quality of the crispy fish scales prepared by the method of the present invention is generally better than that of constant temperature frying and medium temperature frying. The organoleptic quality of the crispy fish scales prepared by constant temperature frying is poor, the color is whitish, there is a sense of grain, the crispness is not good, and the greasy feeling is strong. Although the crispy fish scales prepared by two-stage frying have a better taste than constant temperature frying, there is still a sense of grain, which is not as crispy as the crispy fish scales processed by the method of the present invention. With the increase of frying temperature, the smell and taste scores of the crispy fish scales prepared by the method of the present invention continue to increase, and the color and overall acceptability scores first increase and then decrease. This is because the frying temperature is low, the internal moisture of the product is not completely evaporated, the frying is not thorough, the product has poor crispness, heavy graininess, whitish color, and light fragrance; as the frying temperature increases, the product gradually becomes crispy, the graininess disappears, the color turns yellow, and the fragrance becomes rich; but too high a frying temperature can easily cause the product to burn, resulting in a decrease in the crispy fish scale color score and overall acceptability. Among them, when the medium-temperature frying starting temperature, medium-temperature frying ending temperature, high-temperature frying starting temperature, and high-temperature frying ending temperature of the method of the present invention are 150°C, 170°C, 170°C, and 190°C respectively, the product has a golden color, a crispy taste, and a suitable aroma, and the overall acceptability reaches a maximum value of 8.48.

[0229] In summary, compared with conventional constant temperature frying and two-stage frying, the crispy fish scales prepared by the method of the present invention, i.e., fast continuous heating medium temperature plasticized frying combined with slow continuous heating high temperature crisping frying, have a crispier taste and higher color and flavor acceptability. In particular, in group 4, i.e., when the medium temperature frying starting temperature, the medium temperature frying ending temperature, the high temperature frying starting temperature, and the high temperature frying ending temperature are 150°C, 170°C, 170°C, and 190°C, respectively, the sensory quality of the crispy fish scales prepared is the best.

[0230] Example 5

[0231] The preferred determination of the total frying time in the method of the present invention.

[0232] 1. Experimental methods

[0233] The method of the present invention is used to prepare crispy fish scales, which specifically comprises the following steps:

[0234] (1) Pretreatment of raw fish scales: After selecting and cleaning the fish scales, use a dehydrator to dehydrate for 5 minutes;

[0235] (2) Low-salt pre-marinating and water control: Add 2% salt and 6% cooking wine to the fish scales and marinate at 4°C for 0.5 h;

[0236] (4) Coating with flour: Add 15% corn starch to the pre-marinated fish scales and mix well;

[0237] (5) Frying: This includes two process stages: fast and continuous heating at medium temperature for plasticization frying and slow and continuous heating at high temperature for crisping frying;

[0238] The rapid and continuous heating medium-temperature plasticizing frying is specifically as follows: firstly, the oil temperature in the fryer, i.e., the medium-temperature frying starting temperature, is set to 150° C., and then the fish scales coated with flour are put into the fryer to start frying, and during the frying process, the oil temperature is controlled to rise rapidly and continuously until the oil temperature reaches the medium-temperature frying ending temperature of 170° C., and the frying is terminated; during the frying process, the material is continuously and gently stirred to heat the fish scales evenly and prevent the product from sticking together;

[0239] The slow and continuous heating high-temperature crisping frying is specifically as follows: after the rapid and continuous heating medium-temperature plasticizing frying is completed, the medium-temperature frying end temperature of 170° C. is immediately used as the high-temperature frying starting temperature to continuously perform frying in the same fryer at the next process stage, and the oil temperature is controlled to slowly and continuously rise during the frying process until the oil temperature reaches the high-temperature frying end temperature of 190° C. to terminate the frying; the material is continuously and gently stirred during the frying process to heat the fish scales evenly and prevent the product from sticking together;

[0240] Among them, the total frying time of the two process stages of fast continuous heating medium temperature plasticizing frying and slow continuous heating high temperature crisping frying is controlled to be 150s, 210s, 270s, 330s, and 390s respectively, and the time of fast continuous heating medium temperature plasticizing frying and the time of slow continuous heating high temperature crisping frying are controlled to be 1:2, that is, the time of fast continuous heating medium temperature plasticizing frying and the time of slow continuous heating high temperature crisping frying are 50s, 100s, 70s, 140s, 90s, 180s, 110s, 220s, 130s, and 260s respectively; since the temperature increase amplitudes of fast continuous heating medium temperature plasticizing frying and slow continuous heating high temperature crisping frying are consistent at 20°C, it is only necessary to control the appropriate heating power of the frying facility, such as using a higher heating power in the fast continuous heating medium temperature plasticizing frying stage and a lower heating power in the slow continuous heating high temperature crisping frying stage, so as to achieve continuous rise to the terminal frying temperature in each stage within a given time;

[0241] (6) High-temperature re-frying to control oil and color: After the fish scales are fried for 30 seconds, they are immediately re-fried at 190°C for 40 seconds;

[0242] (7) De-oiling: After high-temperature re-frying, the fish scales are immediately placed in a de-oiling machine at a speed of 1250 r / min for de-oiling for 5 minutes.

[0243] The basic nutritional components, texture characteristics, color, saltiness and sensory scores of the crispy fish scales were tested under the above different frying times.

[0244] 2. Experimental results and analysis

[0245] 2.1 Effect of total frying time on basic nutritional components of crispy fish scales

[0246] Table 19 Effect of total frying time on basic nutritional components of crispy fish scales

[0247]

[0248] Note: Different lowercase letters indicate significant differences (p<0.05).

[0249] As shown in Table 19, frying time has significant effects on the moisture content, solid content, and fat content of crispy fish scales (p<0.05), but has no significant effects on its protein content and ash content (p>0.05). Among them, the moisture content of the product decreases with the extension of frying time; the solid content increases with the extension of frying time; the fat content increases first, then decreases, and then increases with the extension of frying time. When the frying time is 270s, the fat content of crispy fish scales is the lowest at 18.33%.

[0250] 2.2 Effect of total frying time on the texture characteristics of crispy fish scales

[0251] Table 19 Effect of total frying time on the texture characteristics of crispy fish scales

[0252]

[0253] Note: Different lowercase letters indicate significant differences (p<0.05).

[0254] It can be seen from Table 19 that the crispness, brittleness and crispness of the product increase with the extension of frying time. When the frying time is 330s, the crispness, brittleness and crispness of the product reach the maximum, which are 11.13, 9.88 and 21.00 respectively; the hardness value of the product is the minimum, which is 417.21g.

[0255] 2.3 Effect of total frying time on the color of crispy fish scales

[0256] Table 20 Effect of total frying time on the color of crispy fish scales

[0257] Total frying time(s) L a* b* W 150 <![CDATA[55.92±2.82 ab ]]> <![CDATA[-0.78±0.19 a ]]> <![CDATA[5.04±0.47 d ]]> <![CDATA[55.62±2.82 a ]]> 210 <![CDATA[53.04±2.46 b ]]> <![CDATA[-0.86±0.19 ab ]]> <![CDATA[6.30±0.50 c ]]> <![CDATA[52.60±2.40 b ]]> 270 <![CDATA[55.01±2.49 ab ]]> <![CDATA[-1.09±0.23 c ]]> <![CDATA[7.61±0.69 b ]]> <![CDATA[54.35±2.44 ab ]]> 330 <![CDATA[57.82±3.08 a ]]> <![CDATA[-1.03±0.18 bc ]]> <![CDATA[7.88±0.53 b ]]> <![CDATA[57.07±3.08 a ]]> 390 <![CDATA[55.61±2.45 ab ]]> <![CDATA[-1.47±0.16 d ]]> <![CDATA[10.85±1.28 a ]]> <![CDATA[54.25±2.16 ab ]]>

[0258] Note: Different lowercase letters indicate significant differences (p<0.05).

[0259] It can be seen from Table 20 that the a* value of the product decreases with the extension of frying time, and the b* value increases with the extension of frying time; the brightness L value and whiteness W value of the product generally show a trend of first decreasing and then increasing with the extension of frying time. When the frying time is 330s, the L value and W value of the product reach the maximum, which are 57.82 and 57.07 respectively.

[0260] 2.4 Effect of total frying time on sensory scores of crispy fish scales

[0261] Table 21 Effect of total frying time on sensory scores of crispy fish scales

[0262]

[0263] Note: Different lowercase letters indicate significant differences (p<0.05).

[0264] As shown in Table 21, the color, smell and taste scores of the product increased with the extension of frying time, and the greasiness showed a trend of first decreasing, then increasing and then decreasing. When the frying time was 330s, the smell, taste and overall acceptability scores of the product reached the maximum, which were 8.00, 8.21 and 7.84 respectively.

[0265] Taking into account the influence of the total frying time on the nutrition, texture characteristics, color and sensory score of the crispy fish scales, the total frying time selected by the present invention is more appropriately 270-330s.

[0266] Example 6

[0267] Study on the re-explosion time in the method of the present invention

[0268] 1. Experimental methods

[0269] The method of the present invention is adopted to prepare crispy fish scales, wherein the time of re-frying is controlled to be 0s, 20s, 40s, 60s, and 80s respectively, and specifically comprises the following steps:

[0270] (1) Pretreatment of raw fish scales: After selecting and cleaning the fish scales, use a dehydrator to dehydrate for 5 minutes;

[0271] (2) Low-salt pre-marinating and water control: Add 2% salt and 6% cooking wine to the fish scales and marinate at 4°C for 0.5 h;

[0272] (4) Coating with flour: Add 15% corn starch to the pre-marinated fish scales and mix well;

[0273] (5) Frying: This includes two process stages: fast and continuous heating at medium temperature for plasticization frying and slow and continuous heating at high temperature for crisping frying;

[0274] The rapid and continuous heating medium-temperature plasticizing frying is specifically as follows: firstly, the oil temperature in the fryer, i.e., the medium-temperature frying starting temperature, is set to 150° C., and then the fish scales coated with flour are put into the fryer to start frying, and during the frying process, the oil temperature is controlled to be rapidly and continuously raised until the oil temperature reaches the medium-temperature frying ending temperature of 170° C., and the frying time of this process stage is controlled to be 90 seconds; during the frying process, the material is continuously and gently stirred to heat the fish scales evenly and prevent the product from sticking together;

[0275] The slow and continuous heating high-temperature crisping frying is specifically as follows: after the rapid and continuous heating medium-temperature plasticizing frying is completed, the medium-temperature frying end temperature of 170° C. is immediately used as the high-temperature frying starting temperature to continuously perform frying in the same fryer at the next process stage, and the oil temperature is controlled to rise slowly and continuously during the frying process until the oil temperature reaches the high-temperature frying end temperature of 190° C. to terminate the frying, and the frying time of this process stage is controlled to be 180 seconds; the material is continuously and gently stirred during the frying process to heat the fish scales evenly and prevent the product from sticking together;

[0276] (6) High-temperature re-frying to control oil and color: After the fish scales are fried for 30 seconds, they are immediately transferred to a high temperature of 190°C for re-frying for 0 seconds, 20 seconds, 40 seconds, 60 seconds, and 80 seconds;

[0277] (7) De-oiling: After high-temperature re-frying, the fish scales are immediately placed in a de-oiling machine at a speed of 1250 r / min for de-oiling for 5 minutes.

[0278] The moisture content, fat content, texture characteristics, color, saltiness and sensory score of the crispy fish scales were tested under the different re-frying times mentioned above.

[0279] 2. Experimental results and analysis

[0280] 2.1 Effect of re-frying time on moisture and fat content of crispy fish scales

[0281] The results of the effect of re-frying time on the moisture and fat content of crispy fish scales are shown in Figure 3 .Depend on Figure 3 It can be seen that the re-frying time has a significant effect on the moisture content and fat content of crispy fish scales (p<0.05). Among them, the moisture content of the product decreases significantly with the extension of the re-frying time; when the re-frying time is 0s-20s, the fat content of the product changes slowly at first; when the re-frying time is in the range of 20s-60s, the fat content of the product decreases significantly; when the re-frying time is 60s-80s, the fat content of the product does not change significantly.

[0282] 2.2 Effect of re-frying time on the texture characteristics of crispy fish scales

[0283] Table 22 Effect of re-frying time on the texture characteristics of crispy fish scales

[0284]

[0285] Note: Different lowercase letters indicate significant differences (p<0.05).

[0286] As shown in Table 22, with the extension of the re-frying time, the crispness, brittleness and overall crispness of the crispy fish scales increased significantly. When the re-frying time was 40s, the crispness of the crispy fish scales reached a maximum value of 12.63; the crispness of the crispy fish scales re-fried for 60s was 21.50 at most. In summary, when the re-frying time was 40s to 60s, the crispness and crispness of the crispy fish scales were at a better level.

[0287] 2.3 Effect of re-frying time on the color of crispy fish scales

[0288] Table 23 Effect of re-frying time on the color of crispy fish scales

[0289] Re-frying time(s) <![CDATA[L * ]]> <![CDATA[a * ]]> <![CDATA[b * ]]> W 0 <![CDATA[53.89±1.86 b ]]> <![CDATA[-0.68±0.10 a ]]> <![CDATA[6.64±0.32 c ]]> <![CDATA[53.41±1.85 b ]]> 20 <![CDATA[56.40±4.12 ab ]]> <![CDATA[-0.88±0.18 b ]]> <![CDATA[7.56±1.04 c ]]> <![CDATA[55.72±4.02 ab ]]> 40 <![CDATA[57.46±3.02 a ]]> <![CDATA[-0.95±0.08 b ]]> <![CDATA[8.57±0.36 b ]]> <![CDATA[56.59±2.95 a ]]> 60 <![CDATA[56.30±2.01 ab ]]> <![CDATA[-1.20±0.17 c ]]> <![CDATA[10.53±1.05 a ]]> <![CDATA[55.03±2.07 ab ]]> 80 <![CDATA[57.11±2.07 a ]]> <![CDATA[-1.25±0.25 c ]]> <![CDATA[10.68±1.43 a ]]> <![CDATA[55.75±1.74 ab ]]>

[0290] Note: Different lowercase letters indicate significant differences (p<0.05).

[0291] As shown in Table 23, the re-frying time has a significant effect on the brightness (L*), red-green (a*), yellow-blue (b*), and whiteness (W) of the crispy fish scales (p<0.05). As the re-frying time increases, the L*, b*, and W values ​​of the crispy fish scales generally show a trend of gradual increase; the a* value of the product shows a trend of gradual decrease.

[0292] 2.4 Effect of re-frying time on sensory quality of crispy fish scales

[0293] Table 24 Effect of re-frying time on sensory scores of crispy fish scales

[0294]

[0295] Note: Different lowercase letters indicate significant differences (p<0.05).

[0296] As shown in Table 24, the re-frying time has a significant effect on the color, smell, taste, greasiness and overall acceptability of the crispy fish scales (p<0.05). The crispy fish scales re-fried for 0 s are whitish in color, slightly fishy, ​​and granular in taste, and the overall acceptability is poor; with the extension of the re-frying time, the color, smell, taste, greasiness and overall acceptability of the product are improved. The crispy fish scales re-fried for 80s are burnt yellow in color and slightly burnt, and the quality is lower than that of the re-frying for 40s and 60s; the overall acceptability of the product re-fried for 60s is the highest, with a score of 7.37. In general, when the re-frying time is 40s to 60s, the overall acceptability of the crispy fish scales is at a better level.

[0297] Example 7

[0298] Study on the deoiling time in the method of the present invention.

[0299] 1. Experimental methods

[0300] The method of the present invention is used to prepare crispy fish scales, wherein the rotation speed of the deoiling machine is constant at 1250 r / min, and the deoiling time is controlled to be 1 min, 3 min, 5 min, 7 min, and 9 min, respectively, and specifically comprises the following steps:

[0301] (1) Pretreatment of raw fish scales: After selecting and cleaning the fish scales, use a dehydrator to dehydrate for 5 minutes;

[0302] (2) Low-salt pre-marinating and water control: Add 2% salt and 6% cooking wine to the fish scales and marinate at 4°C for 0.5 h;

[0303] (4) Coating with flour: Add 15% corn starch to the pre-marinated fish scales and mix well;

[0304] (5) Frying: This includes two process stages: fast and continuous heating at medium temperature for plasticization frying and slow and continuous heating at high temperature for crisping frying;

[0305] The rapid and continuous heating medium-temperature plasticizing frying is specifically as follows: firstly, the oil temperature in the fryer, i.e., the medium-temperature frying starting temperature, is set to 150° C., and then the fish scales coated with flour are put into the fryer to start frying, and during the frying process, the oil temperature is controlled to be rapidly and continuously raised until the oil temperature reaches the medium-temperature frying ending temperature of 170° C., and the frying time of this process stage is controlled to be 90 seconds; during the frying process, the material is continuously and gently stirred to heat the fish scales evenly and prevent the product from sticking together;

[0306] The slow and continuous heating high-temperature crisping frying is specifically as follows: after the rapid and continuous heating medium-temperature plasticizing frying is completed, the medium-temperature frying end temperature of 170° C. is immediately used as the high-temperature frying starting temperature to continuously perform frying in the same fryer at the next process stage, and the oil temperature is controlled to rise slowly and continuously during the frying process until the oil temperature reaches the high-temperature frying end temperature of 190° C. to terminate the frying, and the frying time of this process stage is controlled to be 180 seconds; the material is continuously and gently stirred during the frying process to heat the fish scales evenly and prevent the product from sticking together;

[0307] (6) High-temperature re-frying to control oil and color: After the fish scales are fried for 30 seconds, they are immediately re-fried at 190°C for 40 seconds;

[0308] (7) Deoiling: After high-temperature re-frying, the fish scales are immediately placed in a deoiling machine at a speed of 1250 r / min for deoiling for 1 min, 3 min, 5 min, 7 min, and 9 min.

[0309] The moisture content, fat content, texture characteristics, color and sensory score of the crispy fish scales were tested under the above-mentioned different deoiling times.

[0310] 2. Experimental results and analysis

[0311] 2.1 Effect of de-oiling time on moisture and fat content of crispy fish scales

[0312] The results of the effect of de-oiling time on the moisture and fat content of crispy fish scales are shown in Figure 4 .Depend on Figure 4 It can be seen that the moisture content of the product first decreases and then increases with the extension of deoiling time; the fat content first decreases sharply and then tends to stabilize with the extension of deoiling time. The fat content of the crispy fish scales deoiled for 0 min is 39.79%. When the deoiling time is 5 min, the fat content of the product is as low as 19.53%, which is 50.92% lower than the fat content of the sample deoiled for 0 min.

[0313] 2.2 Effect of de-oiling time on the texture characteristics of crispy fish scales

[0314] Table 25 Effect of deoiling time on the texture characteristics of crispy fish scales

[0315]

[0316]

[0317] Note: Different lowercase letters indicate significant differences (p<005).

[0318] It can be seen from Table 25 that the de-oiling time has no significant effect on the crispness, brittleness, crunchiness and hardness of the crispy fish scales (p>0.05).

[0319] 2.3 Effect of de-oiling time on the color of crispy fish scales

[0320] Table 26 Effect of deoiling time on the chromaticity of crispy fish scales

[0321] Deoiling time (min) <![CDATA[L * ]]> <![CDATA[a * ]]> <![CDATA[b * ]]> W 1 <![CDATA[54.93±2.42 a ]]> <![CDATA[-1.44±0.46 a ]]> <![CDATA[8.30±0.80 b ]]> <![CDATA[54.13±2.29 a ]]> 3 <![CDATA[55.53±3.42 a ]]> <![CDATA[-1.99±0.22 b ]]> <![CDATA[8.68±0.63 ab ]]> <![CDATA[54.65±3.43 a ]]> 5 <![CDATA[55.10±2.02 a ]]> <![CDATA[-2.12±0.33 b ]]> <![CDATA[9.27±1.06 a ]]> <![CDATA[54.09±1.87 a ]]> 7 <![CDATA[53.80±2.92 a ]]> <![CDATA[-1.93±0.20 b ]]> <![CDATA[7.85±0.67 b ]]> <![CDATA[53.09±2.92 a ]]> 9 <![CDATA[54.00±2.47 a ]]> <![CDATA[-1.79±0.22 5 ]]> <![CDATA[6.82±0.77 c ]]> <![CDATA[53.45+2.41 a ]]>

[0322] Note: Different lowercase letters indicate significant differences (p<0.05).

[0323] It can be seen from Table 26 that the a* (redness and greenness) of the crispy fish scales decreases with the extension of degreasing time; b* (yellowness and blueness) gradually decreases with the extension of degreasing time. This may be because the product with a short degreasing time has more residual oil on the surface and the color is yellowish.

[0324] 2.4 Effect of de-oiling time on sensory quality of crispy fish scales

[0325] Table 27 Effect of de-oiling time on sensory scores of crispy fish scales

[0326]

[0327] Note: Different lowercase letters indicate significant differences (p<0.05).

[0328] As shown in Table 27, the degreasing time has a significant effect on the morphology, color, smell, greasiness and overall acceptability score of the crispy fish scales (p<0.05). Centrifugal degreasing is to use centrifugal force to throw out the fat in the finished product. The applicant found that because the crispy fish scales are thin and crispy, the centrifugal force will produce an extrusion force on the sample, and long-term extrusion will cause the product to break. Therefore, the morphology score of the product gradually decreases with the extension of the degreasing time. When the deoiling time is 7 minutes, the product breaks into very small amounts, and when the deoiling time is 9 minutes, the product breaks into large amounts. Furthermore, contrary to common sense, the greasy feeling does not decrease after the deoiling time is prolonged. This may be because the fish scales are flaky and hard in texture, and most of the residual oil adheres to their surface after frying. Most of the residual oil may be removed after a shorter deoiling time, and if the deoiling time is continued to increase, for example, when the deoiling time is greater than 5 minutes, the crispy fish scales begin to break into small pieces and produce small crumbs. At this time, the residual oil is difficult to reduce as the deoiling time is prolonged, and the crispy fish scale crumbs will produce a heavy and greasy feeling.

[0329] In summary, unlike traditional products, the degreasing time in the present invention is not the longer the better, that is, it is not necessary to use a longer degreasing time, such as a degreasing time greater than 5 minutes to make the residual oil tend to the lowest stable value. On the contrary, when the degreasing time is controlled to 1 to 3 minutes, although the oil content of the crispy fish scales is not at the lowest level, its morphology remains intact, which can avoid the crispy fish scales from breaking into a large amount of debris and causing an increase in greasy feeling. At this time, the product as a whole also has good overall acceptability.

[0330] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing crispy fish scales by medium-temperature plasticization combined with high-temperature crisping, comprising the following steps: (1) pretreatment of raw fish scales, (2) low-salt pre-marinating to control water, (3) coating with flour, (4) frying, (5) high-temperature re-frying to control oil and color, (6) de-oiling, and (7) seasoning, characterized in that: The frying in step (4) includes two process stages: fast continuous heating and medium temperature plasticizing frying and slow continuous heating and high temperature crisping frying; The rapid and continuous heating and medium-temperature plasticizing frying is specifically as follows: firstly, the oil temperature in the fryer, i.e., the medium-temperature frying starting temperature, is set to 150° C., and then the fish scales coated with flour are put into the fryer to start frying, and the oil temperature is controlled to rise rapidly and continuously during the frying process until the oil temperature reaches the medium-temperature frying ending temperature of 170° C., and the frying is terminated; The slow and continuous heating high-temperature crisping frying is specifically as follows: after the rapid and continuous heating medium-temperature plasticizing frying is completed, the medium-temperature frying end temperature of 170° C. is immediately used as the high-temperature frying starting temperature to continuously perform frying in the same frying pan at the next process stage, and the oil temperature is controlled to rise slowly and continuously during the frying process until the oil temperature reaches the high-temperature frying end temperature of 190° C. to terminate the frying; The frying time of the fast and continuous medium-temperature plasticizing frying and the slow and continuous high-temperature crisping frying is controlled to be 1:2, and the total frying time of the two process stages is controlled to be 150s to 390s.

2. The method according to claim 1, characterized in that: In the step (1) of pre-treating the raw material fish scales, the raw material fish scales include but are not limited to the scales of Wuchang fish, grass carp, black carp, crucian carp and carp.

3. The method according to claim 1, characterized in that The specific method of pre-treating the raw fish scales in step (1) is as follows: picking out fish fins, fish bones, fish minced meat, small scales and other debris mixed in the raw fish scales, washing away the mud, blood stains and sticky substances on the surface of the fish scales with clean water, repeatedly rinsing until the water is clear, and placing the cleaned fish scales in a dehydrator to remove surface moisture.

4. The method according to claim 1, characterized in that The specific method of low-salt pre-marinating and water control in step (2) is as follows: based on the weight of fish scales, add 2% to 3% of table salt and 6% to 8% of cooking wine to the fish scales and stir evenly, then marinate in a low temperature environment of 0 to 5°C for 0.5 to 2.5 hours.

5. The method according to claim 1, characterized in that In the step (3) of coating with flour, 15% to 20% corn starch is added based on the weight of the fish scales for coating with flour.

6. The method according to claim 1, characterized in that In the fast and continuous heating and medium-temperature plasticizing frying and the slow and continuous heating and high-temperature crisping frying, the total frying time of the two process stages is controlled to be 270 to 330 seconds.

7. The method according to claim 1, characterized in that The method for high-temperature re-frying, oil control and coloring in step (5) is as follows: after slowly and continuously heating up the temperature and deep-frying the fish scales, take them out and drain the oil, and then immediately re-fry them at a high temperature of 190° C. for 40 seconds to 60 seconds.

8. The method according to claim 1, characterized in that: The deoiling method in step (6) is: The fish scales re-fried in step (5) are placed in a de-oiling machine and centrifuged at a speed of 1250 r / min for de-oiling for 1 min to 3 min.

9. The method according to claim 1, characterized in that: The method of seasoning in step (7) is: Season the crispy fish scales after degreasing in step (6) while they are hot, and add appropriate amount of instant seasoning according to preference. The instant seasoning includes but is not limited to pepper and salt powder, spicy powder, cumin powder, and salted egg yolk powder. The amount of instant seasoning added is 2% to 3% of the mass of the crispy fish scales.

10. A crispy fish scale, characterized in that: Prepared by the method described in any one of claims 1 to 9.

Images