Method for inhibiting MeIQx formation of fried aquatic products

Abstract

The invention provides a method for inhibiting MeIQx formation of deep-fried aquatic products, and belongs to the technical field of deep-fried aquatic products, and the method comprises the following steps: step 1, preparing materials, including preparation of experimental materials; step 2, preparing UVC-GA, and storing the prepared UVC-GA in a dark place at room temperature; step 3, preparing fried aquatic products, namely adding UVC-GA into the aquatic product meat paste, uniformly stirring, and frying at different oil temperatures to obtain the fried aquatic products; and step 4, detecting MeIQx, and detecting the content of MeIQx in the fried aquatic products at different oil temperatures by using UHPLC-MS. According to the method disclosed by the invention, the UVC-GA is added before the squids are fried, so that the generation of MeIQx in the fried squids can be obviously inhibited, and an accurate safety control method is provided for the quality of the fried squids.

Description

Technical Field

[0001] The invention relates to the technical field of fried aquatic products, and in particular to a method for inhibiting the formation of MeIQx in fried aquatic products. Background Art

[0002] Aquatic products are rich in protein, unsaturated fatty acids, vitamins and minerals, and have high nutritional value. Among them, fish are rich in protein, unsaturated fatty acids and vitamin D, which help lower cholesterol, prevent cardiovascular and cerebrovascular diseases and promote brain development; shellfish are rich in trace elements such as zinc and selenium, which help improve immunity; shrimps are rich in protein, unsaturated fatty acids and vitamin A, which help protect vision, skin and immune system.

[0003] There are many ways to cook aquatic products, such as steaming, boiling, stir-frying, deep-frying, and baking. Different cooking methods can preserve their nutrients. During the frying process, the oxidation of fats in aquatic products produces acrolein, glyoxal, oxidized triglyceride monomers, conjugated linoleic acid and other lipid oxidation products, which are key factors promoting the formation of MeIQx.

[0004] MeIQx is a Class 2B mutagenic and carcinogenic compound. MeIQx is mainly produced during the high-temperature processing of protein-rich aquatic products. After glucose and amino acids (glycine) undergo Strecker degradation reactions, the Strecker degradation products undergo a series of complex chemical reactions such as Amadori rearrangement to form pyrazine and pyridine compounds, which then react with creatinine through the Aldol condensation mechanism. MeIQx is commonly found in fried aquatic products and poses a high risk of harm. Accurate reduction and control of MeIQx is an important problem that plagues the development of the aquatic product processing industry.

[0005] Squid has become one of the favorite aquatic products because of its low fat, delicious taste and rich nutrition. Instant foods developed from squid by high-temperature frying (such as squid balls, grilled squid, squid cakes, etc.) are very popular all over the world, but squid is prone to produce MeIQx during the frying process. Therefore, it is very important to find a method to effectively inhibit the formation of MeIQx in squid during the frying process. This provides a control method for the quality and safety control of squid high-temperature processing and develops the MeIQx inhibition theory. Summary of the invention

[0006] The purpose of the present invention is to provide a method for inhibiting the formation of MeIQx in fried aquatic products. The formation of MeIQx in the frying process of squid can be effectively inhibited by inhibiting the MeIQx generated by high-temperature processing of squid paste by UVC-GA, which is conducive to enriching the MeIQx inhibition theory and providing a reference for the development of MeIQx reduction technology for fried squid paste.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] A method for inhibiting the formation of MeIQx in fried aquatic products comprises the following steps:

[0009] Step 1: Prepare materials, including experimental materials;

[0010] Step 2: Prepare UVC-GA, and store the prepared UVC-GA at room temperature away from light;

[0011] Step 3: preparing fried aquatic products, adding UVC-GA to the aquatic product minced meat and stirring evenly, and then frying it at different oil temperatures to obtain fried aquatic products;

[0012] Step 4: Detect MeIQx. Use UHPLC-MS to detect the content of MeIQx in fried aquatic products at different oil temperatures.

[0013] Furthermore, in step 1, the preparation of experimental materials includes: gallic acid, fresh squid, soybean oil, hydrochloric acid, methanol, ethanol and distilled water.

[0014] Furthermore, the specific process of preparing UVC-GA in step 2 is as follows: 2 ml of gallic acid (GA) solution is diluted to 14 mmol with distilled water, the purity of GA is >99%, UV irradiation is used, the distance between the light source and the surface of the gallic acid solution is fixed at 15 cm, and after irradiation for 6 hours, the UVC-GA irradiated solution is stored in the dark at room temperature for later use.

[0015] Furthermore, the wavelength of the prepared UVC-GA was 225 nm and the average intensity was 4540 μW / cm 2 .

[0016] Furthermore, the specific process of preparing the fried aquatic product in step 3 is as follows:

[0017] Step 3.1: The viscera, inner shell and outer skin of the fresh squid were removed and cleaned, and then the squid was cut into small pieces of 3 cm × 3 cm, and the muscle tissue was crushed with a meat grinder. The crushed squid was soaked in 25% anhydrous ethanol for 1 hour, and the mixture of ethanol and oil was discarded. The above steps were repeated three times until the desalination was complete and the ethanol in the squid minced meat was completely volatilized. Then 1 kg of squid minced meat and 25 g of salt were put into a minced meat mixer and stirred evenly, and UVC-GA was added and stirred evenly;

[0018] Step 3.2: Place the squid minced meat obtained in step 3.1 in a culture dish with a radius of 35 mm, and place food-grade paper at the bottom of the culture dish to make 1 cm thick patties, which are wrapped with a sealing film and shaped at a temperature of 4°C for 1 hour. The shaped round cakes are placed in an oil bath for frying. After the fried squid patties are cooled, they are vacuum-packed and stored in a freezer at a temperature of -18°C.

[0019] Furthermore, in step 3.1, the mass percentage of UVC-GA is 0.01%.

[0020] Furthermore, in step 3.2, the oil temperature of the oil bath frying is 100-180°C.

[0021] Furthermore, the specific process of using UHPLC-MS to detect the content of MeIQx in the fried sample in step 4 is as follows:

[0022] Step 4.1: Dry and grind the fried squid patties into powder, weigh 4 g and add them into 25 mL of 0.1 mol / L hydrochloric acid for homogenization for 1 min, 15 s / time, for 4 times in total, and then ultrasonically extract for 15 min;

[0023] Step 4.2: Then, centrifuge at 10,000 r / min for 20 min at 4°C, collect the supernatant, add 25 mL of hydrochloric acid to extract the precipitate again, rotary evaporate the supernatant, combine and concentrate, fix the volume to 25 mL with distilled water, remove the protein by ethanol-freezing method, and then filter with 0.22 μm filter membrane, and perform UHPLC-MS detection with Waters AtlanticsdC18 chromatographic column (250 mm×4.6 mm×3.0 μm).

[0024] Furthermore, the UHPLC chromatographic conditions are as follows:

[0025] Mobile phase: 0.1% formic acid aqueous solution (A)-methanol (B); gradient elution: 0-0.1min, 5% B; 0.1-10min, 5%-100% B; 10-10.5min, 100%-5% B; 10.5-15.5min, 5% B; flow rate was 0.5mL / min, injection volume was 1μL, and column temperature was 35°C.

[0026] Furthermore, the mass spectrometry detection conditions were as follows: electrospray ionization source ionization, positive ion mode, source temperature 130°C, MRM mode, capillary voltage 3.5V; in addition, nitrogen was used as desolvation gas and cone gas, with flow rates of 800L / h and 50L / h, respectively, desolvation temperature was 350°C, and argon was used as collision gas, with a flow rate of 0.13mL / min

[0027] The present invention has the following beneficial effects due to the adoption of the above technical solution:

[0028] In the method of the present invention, by adding UVC-GA before frying the squid, the generation of MeIQx in the fried squid can be significantly inhibited, providing an accurate and safe control method for the quality of the fried squid. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Schematic diagram of the amount of MeIQx generated in fried squid at different temperatures of the present invention;

[0030] Figure 2 Schematic diagram of the microstructure of fried squid at different temperatures of the present invention;

[0031] Figure 3 is a schematic diagram of infrared spectra of fried squid at different temperatures of the present invention;

[0032] Figure 4 is a schematic diagram of the interaction force of frying squid at different temperatures according to the present invention;

[0033] Figure 5 Schematic diagram of Zeta potential of fried squid at different temperatures according to the present invention;

[0034] Figure 6 It is a schematic diagram of the contact angle of fried squid at different temperatures of the present invention. DETAILED DESCRIPTION

[0035] 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 below with reference to the accompanying drawings and preferred embodiments. However, it should be noted that many details listed in the specification are only for the purpose of enabling the reader to have a thorough understanding of one or more aspects of the present invention, and these aspects of the present invention can be implemented even without these specific details.

[0036] Example 1

[0037] A method for inhibiting the formation of MeIQx in fried aquatic products comprises the following steps:

[0038] Step 1: Prepare materials, gallic acid, fresh squid, soybean oil, hydrochloric acid, methanol, ethanol and distilled water;

[0039] Step 2: Prepare UVC-GA. The specific process is as follows: dilute 2 ml of gallic acid solution with distilled water to 14 mmoL, use UV irradiation, and fix the distance between the light source and the surface of the gallic acid solution at 15 cm. After irradiation for 6 hours, the UVC-GA irradiated solution is stored in the dark at room temperature for later use; the wavelength of the prepared UVC-GA is 225 nm, and the average intensity is 4540 μW / cm 2 ;

[0040] Step 3: Prepare fried aquatic products, the specific process is as follows:

[0041] Step 3.1: The viscera, inner shell and outer skin of the fresh squid are removed and cleaned, and then the squid is cut into small pieces of 3 cm × 3 cm, and the muscle tissue is crushed with a meat grinder. The crushed squid is soaked in 25% anhydrous ethanol for 1 hour, and the mixture of ethanol and oil is discarded. The above steps are repeated three times until the desalination is complete, and the ethanol in the squid minced meat is completely volatilized. Then, 1 kg of squid minced meat and 25 g of salt are put into a minced meat mixer and stirred evenly, and 0.01% by mass of UVC-GA is added and stirred evenly;

[0042] Step 3.2: The squid minced meat obtained in step 3.1 is placed in a culture dish with a radius of 35 mm, and food-grade paper is placed at the bottom of the culture dish to form a 1 cm thick patty, which is then wrapped with a sealing film and shaped at a temperature of 4°C for 1 hour. The shaped round cakes are respectively placed in an oil bath at an oil temperature of 100°C for frying. After the fried squid patties are cooled, they are vacuum-packed and stored in a freezer at a temperature of -18°C.

[0043] Step 4: Detect MeIQx. The specific process is as follows:

[0044] Step 4.1: Dry and grind the fried squid patties into powder, weigh 4 g and add them into 25 mL of 0.1 mol / L hydrochloric acid for homogenization for 1 min, 15 s / time, for 4 times in total, and then ultrasonically extract for 15 min;

[0045] Step 4.2: Then, centrifuge at 10,000 r / min for 20 min at 4°C and collect the supernatant, add 25 mL of hydrochloric acid to extract the precipitate again, and then rotary evaporate the supernatant and combine and concentrate, fix the volume to 25 mL with distilled water, remove the protein by ethanol-freezing method, and then filter with 0.22 μm filter membrane, and perform UHPLC-MS detection with Waters AtlanticsdC18 column;

[0046] UHPLC chromatographic conditions are as follows:

[0047] Mobile phase: 0.1% formic acid aqueous solution (A)-methanol (B); gradient elution: 0-0.1min, 5% B; 0.1-10min, 5%-100% B; 10-10.5min, 100%-5% B; 10.5-15.5min, 5% B; flow rate: 0.5mL / min, injection volume: 1μL, column temperature: 35℃;

[0048] The mass spectrometry detection conditions are: electrospray ionization source ionization, positive ion mode, source temperature 130°C, MRM mode, capillary voltage 3.5V; in addition, nitrogen was used as desolvation gas and cone gas, with flow rates of 800L / h and 50L / h respectively, desolvation temperature was 350°C, argon was used as collision gas, with a flow rate of 0.13mL / min Example 2

[0049] A method for inhibiting the formation of MeIQx in fried aquatic products comprises the following steps:

[0050] Step 1: Prepare materials, gallic acid, fresh squid, soybean oil, hydrochloric acid, methanol, ethanol and distilled water;

[0051] Step 2: Prepare UVC-GA. The specific process is as follows: dilute 2 ml of gallic acid solution with distilled water to 14 mmoL, use UV irradiation, and fix the distance between the light source and the surface of the gallic acid solution at 15 cm. After irradiation for 6 hours, the UVC-GA irradiated solution is stored in the dark at room temperature for later use; the wavelength of the prepared UVC-GA is 225 nm, and the average intensity is 4540 μW / cm 2 ;

[0052] Step 3: Prepare fried aquatic products, the specific process is as follows:

[0053] Step 3.1: The viscera, inner shell and outer skin of the fresh squid are removed and cleaned, and then the squid is cut into small pieces of 3 cm × 3 cm, and the muscle tissue is crushed with a meat grinder. The crushed squid is soaked in 25% anhydrous ethanol for 1 hour, and the mixture of ethanol and oil is discarded. The above steps are repeated three times until the desalination is complete, and the ethanol in the squid minced meat is completely volatilized. Then, 1 kg of squid minced meat and 25 g of salt are put into a minced meat mixer and stirred evenly, and 0.01% by mass of UVC-GA is added and stirred evenly;

[0054] Step 3.2: The squid minced meat obtained in step 3.1 is placed in a culture dish with a radius of 35 mm, and food-grade paper is placed at the bottom of the culture dish to form a 1 cm thick patty, which is then wrapped with a sealing film and shaped at a temperature of 4°C for 1 hour. The shaped round cakes are respectively placed in an oil bath at an oil temperature of 120°C for frying. After the fried squid patties are cooled, they are vacuum-packed and stored in a freezer at a temperature of -18°C.

[0055] Step 4: Detect MeIQx. The specific process is as follows:

[0056] Step 4.1: Dry and grind the fried squid patties into powder, weigh 4 g and add them into 25 mL of 0.1 mol / L hydrochloric acid for homogenization for 1 min, 15 s / time, for 4 times in total, and then ultrasonically extract for 15 min;

[0057] Step 4.2: Then, centrifuge at 10,000 r / min for 20 min at 4°C and collect the supernatant, add 25 mL of hydrochloric acid to extract the precipitate again, and then rotary evaporate the supernatant and combine and concentrate, fix the volume to 25 mL with distilled water, remove the protein by ethanol-freezing method, and then filter with 0.22 μm filter membrane, and perform UHPLC-MS detection with Waters AtlanticsdC18 column;

[0058] UHPLC chromatographic conditions are as follows:

[0059] Mobile phase: 0.1% formic acid aqueous solution (A)-methanol (B); gradient elution: 0-0.1min, 5% B; 0.1-10min, 5%-100% B; 10-10.5min, 100%-5% B; 10.5-15.5min, 5% B; flow rate: 0.5mL / min, injection volume: 1μL, column temperature: 35℃;

[0060] The mass spectrometry detection conditions are: electrospray ionization source ionization, positive ion mode, source temperature 130°C, MRM mode, capillary voltage 3.5V; in addition, nitrogen was used as desolvation gas and cone gas, with flow rates of 800L / h and 50L / h respectively, desolvation temperature was 350°C, argon was used as collision gas, with a flow rate of 0.13mL / min Example 3

[0061] A method for inhibiting the formation of MeIQx in fried aquatic products comprises the following steps:

[0062] Step 1: Prepare materials, gallic acid, fresh squid, soybean oil, hydrochloric acid, methanol, ethanol and distilled water;

[0063] Step 2: Prepare UVC-GA. The specific process is as follows: dilute 2 ml of gallic acid solution with distilled water to 14 mmoL, use UV irradiation, and fix the distance between the light source and the surface of the gallic acid solution at 15 cm. After irradiation for 6 hours, the UVC-GA irradiated solution is stored in the dark at room temperature for later use; the wavelength of the prepared UVC-GA is 225 nm, and the average intensity is 4540 μW / cm 2 ;

[0064] Step 3: Prepare fried aquatic products, the specific process is as follows:

[0065] Step 3.1: The viscera, inner shell and outer skin of the fresh squid are removed and cleaned, and then the squid is cut into small pieces of 3 cm × 3 cm, and the muscle tissue is crushed with a meat grinder. The crushed squid is soaked in 25% anhydrous ethanol for 1 hour, and the mixture of ethanol and oil is discarded. The above steps are repeated three times until the desalination is complete, and the ethanol in the squid minced meat is completely volatilized. Then, 1 kg of squid minced meat and 25 g of salt are put into a minced meat mixer and stirred evenly, and 0.01% by mass of UVC-GA is added and stirred evenly;

[0066] Step 3.2: The squid minced meat obtained in step 3.1 is placed in a culture dish with a radius of 35 mm, and food-grade paper is placed at the bottom of the culture dish to form a 1 cm thick patty, which is then wrapped with a sealing film and shaped at a temperature of 4°C for 1 hour. The shaped round cakes are respectively placed in an oil bath pot at an oil temperature of 140°C for frying. After the fried squid patties are cooled, they are vacuum-packed and stored in a freezer at a temperature of -18°C;

[0067] Step 4: Detect MeIQx. The specific process is as follows:

[0068] Step 4.1: Dry and grind the fried squid patties into powder, weigh 4 g and add them into 25 mL of 0.1 mol / L hydrochloric acid for homogenization for 1 min, 15 s / time, for 4 times in total, and then ultrasonically extract for 15 min;

[0069] Step 4.2: Then, centrifuge at 10,000 r / min for 20 min at 4°C and collect the supernatant, add 25 mL of hydrochloric acid to extract the precipitate again, and then rotary evaporate the supernatant and combine and concentrate, fix the volume to 25 mL with distilled water, remove the protein by ethanol-freezing method, and then filter with 0.22 μm filter membrane, and perform UHPLC-MS detection with Waters AtlanticsdC18 column;

[0070] UHPLC chromatographic conditions are as follows:

[0071] Mobile phase: 0.1% formic acid aqueous solution (A)-methanol (B); gradient elution: 0-0.1min, 5% B; 0.1-10min, 5%-100% B; 10-10.5min, 100%-5% B; 10.5-15.5min, 5% B; flow rate: 0.5mL / min, injection volume: 1μL, column temperature: 35℃;

[0072] The mass spectrometry detection conditions are: electrospray ionization source ionization, positive ion mode, source temperature 130°C, MRM mode, capillary voltage 3.5V; in addition, nitrogen was used as desolvation gas and cone gas, with flow rates of 800L / h and 50L / h respectively, desolvation temperature was 350°C, argon was used as collision gas, with a flow rate of 0.13mL / min Example 4

[0073] A method for inhibiting the formation of MeIQx in fried aquatic products comprises the following steps:

[0074] Step 1: Prepare materials, gallic acid, fresh squid, soybean oil, hydrochloric acid, methanol, ethanol and distilled water;

[0075] Step 2: Prepare UVC-GA. The specific process is as follows: dilute 2 ml of gallic acid solution with distilled water to 14 mmoL, use UV irradiation, and fix the distance between the light source and the surface of the gallic acid solution at 15 cm. After irradiation for 6 hours, the UVC-GA irradiated solution is stored in the dark at room temperature for later use; the wavelength of the prepared UVC-GA is 225 nm, and the average intensity is 4540 μW / cm 2 ;

[0076] Step 3: Prepare fried aquatic products, the specific process is as follows:

[0077] Step 3.1: The viscera, inner shell and outer skin of the fresh squid are removed and cleaned, and then the squid is cut into small pieces of 3 cm × 3 cm, and the muscle tissue is crushed with a meat grinder. The crushed squid is soaked in 25% anhydrous ethanol for 1 hour, and the mixture of ethanol and oil is discarded. The above steps are repeated three times until the desalination is complete, and the ethanol in the squid minced meat is completely volatilized. Then, 1 kg of squid minced meat and 25 g of salt are put into a minced meat mixer and stirred evenly, and 0.01% by mass of UVC-GA is added and stirred evenly;

[0078] Step 3.2: The squid minced meat obtained in step 3.1 is placed in a culture dish with a radius of 35 mm, and food-grade paper is placed at the bottom of the culture dish to form a 1 cm thick patty, which is then wrapped with a sealing film and shaped at a temperature of 4°C for 1 hour. The shaped round cakes are respectively placed in an oil bath pot at an oil temperature of 160°C for frying. After the fried squid patties are cooled, they are vacuum-packed and stored in a freezer at a temperature of -18°C.

[0079] Step 4: Detect MeIQx. The specific process is as follows:

[0080] Step 4.1: Dry and grind the fried squid patties into powder, weigh 4 g and add them into 25 mL of 0.1 mol / L hydrochloric acid for homogenization for 1 min, 15 s / time, for 4 times in total, and then ultrasonically extract for 15 min;

[0081] Step 4.2: Then, centrifuge at 10,000 r / min for 20 min at 4°C and collect the supernatant, add 25 mL of hydrochloric acid to extract the precipitate again, and then rotary evaporate the supernatant and combine and concentrate, fix the volume to 25 mL with distilled water, remove the protein by ethanol-freezing method, and then filter with 0.22 μm filter membrane, and perform UHPLC-MS detection with Waters AtlanticsdC18 column;

[0082] UHPLC chromatographic conditions are as follows:

[0083] Mobile phase: 0.1% formic acid aqueous solution (A)-methanol (B); gradient elution: 0-0.1min, 5% B; 0.1-10min, 5%-100% B; 10-10.5min, 100%-5% B; 10.5-15.5min, 5% B; flow rate: 0.5mL / min, injection volume: 1μL, column temperature: 35℃;

[0084] The mass spectrometry detection conditions are: electrospray ionization source ionization, positive ion mode, source temperature 130°C, MRM mode, capillary voltage 3.5V; in addition, nitrogen was used as desolvation gas and cone gas, with flow rates of 800L / h and 50L / h respectively, desolvation temperature was 350°C, argon was used as collision gas, with a flow rate of 0.13mL / min. Example 5

[0085] A method for inhibiting the formation of MeIQx in fried aquatic products comprises the following steps:

[0086] Step 1: Prepare materials, gallic acid, fresh squid, soybean oil, hydrochloric acid, methanol, ethanol and distilled water;

[0087] Step 2: Prepare UVC-GA. The specific process is as follows: dilute 2 ml of gallic acid solution with distilled water to 14 mmoL, use UV irradiation, and fix the distance between the light source and the surface of the gallic acid solution at 15 cm. After irradiation for 6 hours, the UVC-GA irradiated solution is stored in the dark at room temperature for later use; the wavelength of the prepared UVC-GA is 225 nm, and the average intensity is 4540 μW / cm 2 ;

[0088] Step 3: Prepare fried aquatic products, the specific process is as follows:

[0089] Step 3.1: The viscera, inner shell and outer skin of the fresh squid are removed and cleaned, and then the squid is cut into small pieces of 3 cm × 3 cm, and the muscle tissue is crushed with a meat grinder. The crushed squid is soaked in 25% anhydrous ethanol for 1 hour, and the mixture of ethanol and oil is discarded. The above steps are repeated three times until the desalination is complete, and the ethanol in the squid minced meat is completely volatilized. Then, 1 kg of squid minced meat and 25 g of salt are put into a minced meat mixer and stirred evenly, and 0.01% by mass of UVC-GA is added and stirred evenly;

[0090] Step 3.2: The squid minced meat obtained in step 3.1 is placed in a culture dish with a radius of 35 mm, and food-grade paper is placed at the bottom of the culture dish to form a 1 cm thick patty, which is then wrapped with a sealing film and shaped at a temperature of 4°C for 1 hour. The shaped round cakes are respectively placed in an oil bath at an oil temperature of 180°C for frying. After the fried squid patties are cooled, they are vacuum-packed and stored in a freezer at a temperature of -18°C.

[0091] Step 4: Detect MeIQx. The specific process is as follows:

[0092] Step 4.1: Dry and grind the fried squid patties into powder, weigh 4 g and add them into 25 mL of 0.1 mol / L hydrochloric acid for homogenization for 1 min, 15 s / time, for 4 times in total, and then ultrasonically extract for 15 min;

[0093] Step 4.2: Then, centrifuge at 10,000 r / min for 20 min at 4°C and collect the supernatant, add 25 mL of hydrochloric acid to extract the precipitate again, and then rotary evaporate the supernatant and combine and concentrate, fix the volume to 25 mL with distilled water, remove the protein by ethanol-freezing method, and then filter with 0.22 μm filter membrane, and perform UHPLC-MS detection with Waters AtlanticsdC18 column;

[0094] UHPLC chromatographic conditions are as follows:

[0095] Mobile phase: 0.1% formic acid aqueous solution (A)-methanol (B); gradient elution: 0-0.1min, 5% B; 0.1-10min, 5%-100% B; 10-10.5min, 100%-5% B; 10.5-15.5min, 5% B; flow rate: 0.5mL / min, injection volume: 1μL, column temperature: 35℃;

[0096] The mass spectrometry detection conditions are: electrospray ionization source ionization, positive ion mode, source temperature 130°C, MRM mode, capillary voltage 3.5V; in addition, nitrogen is used as desolvation gas and cone gas, with flow rates of 800L / h and 50L / h respectively, the desolvation temperature is 350°C, and argon is used as collision gas with a flow rate of 0.13mL / min.

[0097] A method for inhibiting the formation of MeIQx in fried aquatic products comprises the following steps:

[0098] Step 1: Prepare materials, gallic acid, fresh squid, soybean oil, hydrochloric acid, methanol, ethanol and distilled water;

[0099] Step 2: Prepare UVC-GA. The specific process is as follows: dilute 2 ml of gallic acid solution with distilled water to 14 mmoL, use UV irradiation, and fix the distance between the light source and the surface of the gallic acid solution at 15 cm. After irradiation for 6 hours, the UVC-GA irradiated solution is stored in the dark at room temperature for later use; the wavelength of the prepared UVC-GA is 225 nm, and the average intensity is 4540 μW / cm 2 ;

[0100] Step 3: Prepare fried aquatic products, the specific process is as follows:

[0101] Step 3.1: The viscera, inner shell and outer skin of the fresh squid are removed and cleaned, and then the squid is cut into small pieces of 3 cm × 3 cm, and the muscle tissue is crushed with a meat grinder. The crushed squid is soaked in 25% anhydrous ethanol for 1 hour, and the mixture of ethanol and oil is discarded. The above steps are repeated three times until the desalination is complete, and the ethanol in the squid minced meat is completely volatilized. Then, 1 kg of squid minced meat and 25 g of salt are put into a minced meat mixer and stirred evenly, and 0.01% by mass of UVC-GA is added and stirred evenly;

[0102] Step 3.2: The squid minced meat obtained in step 3.1 is placed in a culture dish with a radius of 35 mm, and food-grade paper is placed at the bottom of the culture dish to form a 1 cm thick patty, which is then wrapped with a sealing film and shaped at a temperature of 4°C for 1 hour. The shaped round cakes are respectively placed in an oil bath at an oil temperature of 200°C for frying. After the fried squid patties are cooled, they are vacuum-packed and stored in a freezer at a temperature of -18°C.

[0103] Step 4: Detect MeIQx. The specific process is as follows:

[0104] Step 4.1: Dry and grind the fried squid patties into powder, weigh 4 g and add them into 25 mL of 0.1 mol / L hydrochloric acid for homogenization for 1 min, 15 s / time, for 4 times in total, and then ultrasonically extract for 15 min;

[0105] Step 4.2: Then, centrifuge at 10,000 r / min for 20 min at 4°C and collect the supernatant, add 25 mL of hydrochloric acid to extract the precipitate again, and then rotary evaporate the supernatant and combine and concentrate, fix the volume to 25 mL with distilled water, remove the protein by ethanol-freezing method, and then filter with 0.22 μm filter membrane, and perform UHPLC-MS detection with Waters AtlanticsdC18 column;

[0106] UHPLC chromatographic conditions are as follows:

[0107] Mobile phase: 0.1% formic acid aqueous solution (A)-methanol (B); gradient elution: 0-0.1min, 5% B; 0.1-10min, 5%-100% B; 10-10.5min, 100%-5% B; 10.5-15.5min, 5% B; flow rate: 0.5mL / min, injection volume: 1μL, column temperature: 35℃;

[0108] The mass spectrometry detection conditions are: electrospray ionization source ionization, positive ion mode, source temperature 130°C, MRM mode, capillary voltage 3.5V; in addition, nitrogen is used as desolvation gas and cone gas, with flow rates of 800L / h and 50L / h respectively, desolvation temperature is 350°C, argon is used as collision gas, with a flow rate of 0.13mL / min.

[0109] A method for inhibiting the formation of MeIQx in fried aquatic products comprises the following steps:

[0110] Step 1: Prepare materials, gallic acid, fresh squid, soybean oil, hydrochloric acid, methanol, ethanol and distilled water;

[0111] Step 2: Prepare UVC-GA. The specific process is as follows: dilute 2 ml of gallic acid solution with distilled water to 14 mmoL, use UV irradiation, and fix the distance between the light source and the surface of the gallic acid solution at 15 cm. After irradiation for 6 hours, the UVC-GA irradiated solution is stored in the dark at room temperature for later use; the wavelength of the prepared UVC-GA is 225 nm, and the average intensity is 4540 μW / cm 2 ;

[0112] Step 3: Prepare fried aquatic products, the specific process is as follows:

[0113] Step 3.1: The viscera, inner shell and outer skin of the fresh squid are removed and cleaned, and then the squid is cut into small pieces of 3 cm × 3 cm, and the muscle tissue is crushed with a meat grinder. The crushed squid is soaked in 25% anhydrous ethanol for 1 hour, and the mixture of ethanol and oil is discarded. The above steps are repeated three times until the desalination is complete, and the ethanol in the squid minced meat is completely volatilized. Then, 1 kg of squid minced meat and 25 g of salt are put into a minced meat mixer and stirred evenly, and 0.01% by mass of UVC-GA is added and stirred evenly;

[0114] Step 3.2: The squid minced meat obtained in step 3.1 is placed in a culture dish with a radius of 35 mm, and food-grade paper is placed at the bottom of the culture dish to form a 1 cm thick patty, which is then wrapped with a sealing film and shaped at a temperature of 4°C for 1 hour. The shaped round cakes are respectively placed in an oil bath at an oil temperature of 220°C for frying. After the fried squid patties are cooled, they are vacuum-packed and stored in a freezer at a temperature of -18°C.

[0115] Step 4: Detect MeIQx. The specific process is as follows:

[0116] Step 4.1: Dry and grind the fried squid patties into powder, weigh 4 g and add them into 25 mL of 0.1 mol / L hydrochloric acid for homogenization for 1 min, 15 s / time, for 4 times in total, and then ultrasonically extract for 15 min;

[0117] Step 4.2: Then, centrifuge at 10,000 r / min for 20 min at 4°C and collect the supernatant, add 25 mL of hydrochloric acid to extract the precipitate again, and then rotary evaporate the supernatant and combine and concentrate, fix the volume to 25 mL with distilled water, remove the protein by ethanol-freezing method, and then filter with 0.22 μm filter membrane, and perform UHPLC-MS detection with Waters AtlanticsdC18 column;

[0118] UHPLC chromatographic conditions are as follows:

[0119] Mobile phase: 0.1% formic acid aqueous solution (A)-methanol (B); gradient elution: 0-0.1min, 5% B; 0.1-10min, 5%-100% B; 10-10.5min, 100%-5% B; 10.5-15.5min, 5% B; flow rate: 0.5mL / min, injection volume: 1μL, column temperature: 35℃;

[0120] The mass spectrometry detection conditions were as follows: electrospray ionization source ionization, positive ion mode, source temperature 130°C, MRM mode, capillary voltage 3.5V; in addition, nitrogen was used as desolvation gas and cone gas, with flow rates of 800L / h and 50L / h, respectively, desolvation temperature of 350°C, and argon was used as collision gas with a flow rate of 0.13mL / min control group

[0121] The control group was set without adding UVC-GA, and the other steps were the same as those in the embodiment.

[0122] Examples 1-5 and Comparative Examples 1-2 are denoted as UVC-GA, and the control group is denoted as CON.

[0123] The amount of MeIQx produced by fried squid paste in UVC-GA and control groups Figure 1 As shown. With the increase of frying temperature, the amount of MeIQx generated gradually increased, reaching a maximum value of 2.12ng / g at 220℃. After adding UVC-GA to the squid sample, when the frying temperature was lower than 200℃, UVC-GA had a significant inhibitory effect on the generation of MeIQx; when the frying temperature was greater than 200℃, the inhibitory effect disappeared, and the amount of MeIQx generated in the fried squid in the UVC-GA group and the control group was equivalent. From the above, it can be seen that the frying temperature significantly affects the amount of MeIQx generated in fried squid minced meat, UVC-GA significantly inhibits the generation of MeIQx in fried squid minced meat, and 200℃ is the upper limit of the temperature at which UVC-GA inhibits the generation of MeIQx in squid minced meat.

[0124] The obtained deep-fried squid patties were observed using SEM.

[0125] The obtained fried squid patties were cut into small pieces, vacuum freeze-dried and sent to the electron microscope platform of Huazhong Agricultural University for sample preparation. After gold plating, they were observed by a scanning electron microscope (JSM-6390LV), and the appropriate field of view and magnification were selected to record the image.

[0126] Microstructural changes such as Figure 2 (In the figure, C represents the control group; G represents the Example 1-7 group; the numbers represent the frying temperature) As shown, the network structure of the fried squid paste in the control group is not dense, the surface is rough and uneven, there are many wrinkles, the pore size is large, and its microstructure does not change significantly with the increase of temperature. The microstructure of the fried fish paste in the UVC-GA group under high-temperature frying is significantly different. At 100-160°C, the fish paste network structure is dense, the surface is delicate and smooth, and there are few wrinkles; when it exceeds 180°C, the wrinkles increase, and gaps appear between the wrinkles. At 200-220°C, the fish paste structure changes greatly, the wrinkles increase and the height increases, and more holes appear, the hole sizes are uneven, and the network structure is loose. From the above, it can be seen that during high-temperature frying, UVC-GA can maintain the fish paste network structure in a slightly high temperature environment, making the surface more dense and smooth, and the fish paste network structure changes significantly when the temperature is transitioned.

[0127] The obtained fried squid patties were subjected to infrared spectroscopy analysis

[0128] The fried squid patties were freeze-dried, and appropriate amounts of dried potassium bromide powder and fried squid patties samples (potassium bromide: minced fish = 100:1) were fully ground in a mortar and tableted. After tableting, the FT-IR spectrum of the samples was measured using a Fourier transform infrared spectrometer (IS50 Suzhou Ops Plasma Technology Co., Ltd.). The attenuated total reflectance mode was used to measure the FT-IR spectrum of the samples at 4000 to 400 cm -1 The measurement is carried out within the wave number range of 4cm -1 Each spectrum was collected with 64 scans at a resolution of 1000 nm and air as the background.

[0129] Near infrared spectroscopy changes such as Figure 3 As shown in the figure, all squid surimi have characteristic absorption peaks of infrared spectrum of protein (Amide A, B, I, II and III), and the trend of infrared spectrum change is basically the same, but the absorption intensity of each absorption peak is different at different frying temperatures; at the same frying temperature, the absorption intensity of each absorption peak of the samples in the control group and UVC-GA group is significantly different, mainly in the two absorption regions of amide A and amide I. The amide A absorption peak of all surimi is around 2920cm-1, but the peak intensity of UVC-GA is slightly increased. The amide I band of the control group and UVC-GA group red-shifts to 1750cm-1 and a strong absorption peak appears, which is manifested as the C=O stretching vibration of the amide I band. Compared with the control group, the C=O stretching vibration of the amide I band of UVC-GA is stronger. When UVC-GA is added to squid surimi, the characteristic absorption peaks of amide A and amide I bands are blue-shifted, and are slightly higher than those of the control group without addition. From the above, it can be seen that UVC-GA has a significant protective effect on the protein structure of surimi.

[0130] The obtained fried squid patties were subjected to interaction force measurement

[0131] Ionic bond determination: Weigh 1 g of the fried squid patties sample obtained in Example 1-7, add 10 mL of A1 extract (0.6 mol / L NaCl), homogenize at 5 000 r / min for 2 min, place at 4°C for 1 h, and centrifuge at 4°C and 18 600 r / min for 25 min. The supernatant (A) is stored at 4°C.

[0132] Hydrogen bond determination: Add 10 mL of A2 extract (a mixture of 1.5 mol / L urea and 0.6 mol / L NaCl) to the precipitate obtained by the above centrifugation, homogenize at 5 000 r / min for 2 min, place at 4°C for 1 h, centrifuge at 4°C and 18 600 r / min for 25 min, and store the supernatant (B) at 4°C.

[0133] Hydrophobic interaction determination: Add 10 mL of A3 extract (a mixture of 8 mol / L urea and 0.6 mol / L NaCl) to the above centrifugal precipitate, homogenize at 5,000 r / min for 2 min, place at 4°C for 1 h, centrifuge at 4°C and 18,600 r / min for 25 min, and store the supernatant at 4°C. Repeat this step, and combine the supernatants (C) obtained from the two centrifugations and store them at 4°C.

[0134] Disulfide bond determination: continue to add 10mL of A4 extract (a mixture of 0.5mol / L β-mercaptoethanol, 0.6mol / L NaCl and 8mol / L urea, pH 7) to the precipitate, homogenize at 5000r / min for 2min, place at 4℃ for 1h, centrifuge at 4℃ and 18,600r / min, and store the supernatant (D) at 4℃.

[0135] After centrifugation in the above steps, the supernatant obtained was added with an equal volume of 20% TCA, centrifuged at 3950r / min for 15min, the supernatant was discarded, 1mL of 1mol / L NaOH solution was added to the precipitate and placed at 4°C, and the protein content was determined by the biuret method. The contribution of ionic bonds, hydrogen bonds, hydrophobic interactions, and disulfide bonds were expressed as the relative mass fractions of proteins dissolved in A, B, C, and D, respectively. The interaction between protein molecules determines the stability of the fish paste network structure.

[0136] Figure 4 The intermolecular interactions of fried squid mince at different frying temperatures were demonstrated. Among the chemical interactions between the surimi protein molecules in the control group and the UVC-GA group, hydrophobic interactions dominated, followed by disulfide bonds, ionic bonds, and hydrogen bonds. At the same frying temperature level, the hydrophobic interactions between the surimi protein molecules in the UVC-GA group were stronger than those in the control group. In the control group, the hydrophobic interactions at 120°C were significantly higher than those at other frying temperatures, while the hydrophobic interactions of the surimi in the UVC-GA group were significantly higher than those at other frying temperatures at 120°C-160°C. At the same frying temperature, the ionic bond strength of the surimi in the UVC-GA group was greater than that in the control group. From the above, it can be seen that UVC-GA can enhance the hydrophobic interactions and ionic bonds of squid mince, which helps to stabilize the internal network structure of the surimi.

[0137] Zeta potential measurement of the deep-fried squid patties obtained

[0138] The fried squid patties thawed in the refrigerator were cut into small pieces and crushed in a chopper. A certain amount of pure water was added to prepare a solution with a mass concentration of 10 mg / mL. The solution was stirred at 5000 r / min for 2 min using a high-speed homogenizer, and then the solution was centrifuged at a speed of 8000 r / min for 2 min to obtain the sample to be tested. The Zeta potential of each group of solutions was measured using a Malvern nanoparticle size potential analyzer. The solution to be tested was carefully injected into the sample pool to avoid bubbles that would affect the results. The two sections of the electrode were kept flat during the test, the test temperature was set to 25°C, the equilibrium time was 30s, and each sample was measured 3 times to take the average value.

[0139] like Figure 5 As shown in the figure, the Zeta potential of all samples is negative, indicating that most of the amino acids on the surface of the samples are negatively charged. The higher the absolute value of the potential, the stronger its ability to resist intermolecular aggregation through electrostatic repulsion. Except for 120℃, the absolute values ​​of the Zeta potential of the surimi in the UVC-GA group were higher than those in the control group. The potential of the surimi in the control group ranged from -13.4mV to -16.27mV, and the Zeta potential of the surimi in the UVC-GA group ranged from -15.7mV to -17.3mV. With the increase of frying temperature, the Zeta potential of the surimi showed a trend of first decreasing, then increasing, and then decreasing. The absolute value of the Zeta potential of the surimi in the control group reached a maximum value of 16.27mV at 120℃, and the absolute value of the Zeta potential of the surimi in the UVC-GA group reached a maximum value of 17.3mV at 100℃. From the above, it can be seen that the frying temperature affects the Zeta potential of squid surimi, and the gallic acid of UVC-GA neutralizes part of the positive charge on the surface of the surimi, making the Zeta potential of the surimi highly negative.

[0140] The obtained fried squid patties were analyzed for hydrophobicity determination

[0141] After the fried squid patties were freeze-dried, 500 mg of the sample was ground in a mortar and then made into thin slices by an infrared tablet press. The contact angle of ultrapure water on the fish paste thin slices was measured by a contact angle analyzer (Dataphysics OCA15EC). The volume of ultrapure water was 3 μL, and three parallel measurements were made for each sample. The contact angle formed by ultrapure water on the thin slice was calculated by the online professional software SCA20. The contact angle describes the ability of a liquid to spread on a solid surface and reflects the hydrophobicity of the surface of an object.

[0142] Figure 6(In the figure, C represents the control group; G represents the UVC-GA group; the numbers represent the frying temperature) shows the contact angles of fried squid paste under different treatments, and all θ are less than 90°, indicating that all fried fish paste samples are dominated by hydrophilic behavior. At different frying temperatures, the contact angle change trends of the UVC-GA group and the control group are basically the same, and the hydrophobicity continues to increase with the increase of frying temperature. After adding UVC-GA, the contact angle of the UVC-GA group is greater than that of the control group at all temperatures. When the temperature is below 180°C, the contact angle of the UVC-GA group is always less than 50°. When the temperature is 180°C and above, its contact angle is greater than 50°, that is, UVC-GA increases the contact angle of fried squid paste, weakens hydrophilicity, and enhances hydrophobicity. From the above, it can be seen that UVC-GA can enhance the hydrophobicity of squid paste.

[0143] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for inhibiting the formation of MeIQx in fried aquatic products, characterized in that: The following steps are involved: Step 1: Prepare materials, including experimental materials; Step 2: Prepare UVC-GA, and store the prepared UVC-GA at room temperature away from light; Step 3: preparing fried aquatic products, adding UVC-GA to the aquatic product minced meat and stirring evenly, and then frying it at different oil temperatures to obtain fried aquatic products; Step 4: Detect MeIQx. Use UHPLC-MS to detect the content of MeIQx in fried aquatic products at different oil temperatures.

2. The method for inhibiting the formation of MeIQx in fried aquatic products according to claim 1, characterized in that: In step 1, the preparation of experimental materials includes: gallic acid, fresh squid, soybean oil, hydrochloric acid, methanol, ethanol and distilled water.

3. The method for inhibiting the formation of MeIQx in fried aquatic products according to claim 1, characterized in that: The specific process of preparing UVC-GA in step 2 is as follows: 2 ml of gallic acid solution is diluted to 14 mmoL with distilled water, UV irradiation is performed, and the distance between the light source and the surface of the gallic acid solution is fixed at 15 cm. After irradiation for 6 hours, the UVC-GA irradiated solution is stored in the dark at room temperature for later use.

4. The method for inhibiting the formation of MeIQx in fried aquatic products according to claim 3, characterized in that: The wavelength of UVC-GA was 225 nm and the average intensity was 4540 μW / cm 2 .

5. The method for inhibiting the formation of MeIQx in fried aquatic products according to claim 1, characterized in that: The specific process of preparing fried aquatic products in step 3 is: Step 3.1: The viscera, inner shell and outer skin of the fresh squid were removed and cleaned, and then the squid was cut into small pieces of 3 cm × 3 cm, and the muscle tissue was crushed with a meat grinder. The crushed squid was soaked in 25% anhydrous ethanol for 1 hour, and the mixture of ethanol and oil was discarded. The above steps were repeated three times until the desalination was complete and the ethanol in the squid minced meat was completely volatilized. Then 1 kg of squid minced meat and 25 g of salt were put into a minced meat mixer and stirred evenly, and UVC-GA was added and stirred evenly; Step 3.2: Place the squid minced meat obtained in step 3.1 in a culture dish with a radius of 35 mm, and place food-grade paper at the bottom of the culture dish to make 1 cm thick patties, which are wrapped with a sealing film and shaped at a temperature of 4°C for 1 hour. The shaped round cakes are placed in an oil bath for frying. After the fried squid patties are cooled, they are vacuum-packed and stored in a freezer at a temperature of -18°C.

6. The method for inhibiting the formation of MeIQx in fried aquatic products according to claim 5, characterized in that: The mass percentage of UVC-GA in step 3.1 is 0.01%.

7. The method for inhibiting the formation of MeIQx in fried aquatic products according to claim 5, characterized in that: In step 3.2, the oil temperature of the oil bath frying is 100-180°C.

8. The method for inhibiting the formation of MeIQx in fried aquatic products according to claim 1, characterized in that: The specific process of using UHPLC-MS to detect the content of MeIQx in fried samples in step 4 is as follows: Step 4.1: Dry and grind the fried squid patties into powder, weigh 4 g and add them into 25 mL of 0.1 mol / L hydrochloric acid for homogenization for 1 min, 15 s / time, for 4 times in total, and then ultrasonically extract for 15 min; Step 4.2: Then, centrifuge at 10,000 r / min for 20 min at 4°C and collect the supernatant, add 25 mL of hydrochloric acid to extract the precipitate again, rotary evaporate the supernatant, combine and concentrate, fix the volume to 25 mL with distilled water, remove the protein by ethanol-freezing method, and then filter with 0.22 μm filter membrane and perform UHPLC-MS detection using Waters Atlantics dC18 column.

9. The method for inhibiting the formation of MeIQx in fried aquatic products according to claim 8, characterized in that: UHPLC chromatographic conditions are as follows: Mobile phase: 0.1% formic acid aqueous solution (A)-methanol (B); gradient elution: 0-0.1min, 5% B; 0.1-10min, 5%-100% B; 10-10.5min, 100%-5% B; 10.5-15.5min, 5% B; flow rate was 0.5mL / min, injection volume was 1μL, and column temperature was 35°C.

10. The method for inhibiting the formation of MeIQx in fried aquatic products according to claim 8, characterized in that: The mass spectrometry detection conditions were as follows: electrospray ionization source ionization, positive ion mode, source temperature 130°C, MRM mode, capillary voltage 3.5V; in addition, nitrogen was used as the desolvation gas and cone gas, with flow rates of 800L / h and 50L / h respectively, the desolvation temperature was 350°C, and argon was used as the collision gas, with a flow rate of 0.13mL / min.

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