A method for enriching antioxidant peptides in duck meat by ultrasound-assisted maturation

Abstract

The present invention provides a method for enriching antioxidant peptides in duck meat by ultrasonic synergistic maturation, and belongs to the technical field of functional duck meat processing. The present invention selects male Muscovy ducks of about 72 days of age, divides them into vacuum packages, and then performs ultrasonic treatment, and then places the treated samples in a constant temperature and humidity incubator at 4°C and 60% relative humidity (RH) for post-slaughter maturation; and measures various indicators such as water retention and tenderness of each group of duck breast samples at different time points after ultrasound. Crude peptides are extracted from duck breast meat at different maturation times, and the crude peptides are measured for peptide content and antioxidant activity; the mining of antioxidant peptides in Muscovy duck meat and the development of high-value products are studied to improve the edible and nutritional quality of duck meat products, and promote the deep processing and high-value development of duck meat. The polypeptide with the strongest antioxidant activity is identified, and artificial synthesis verification is performed to obtain the polypeptide sequence with the strongest antioxidant activity separated from the Muscovy duck source polypeptide.

Description

Technical Field

[0001] The invention belongs to the technical field of functional duck meat processing and relates to a method for enriching antioxidant peptides in duck meat through ultrasound-coordinated maturation. Background Art

[0002] Due to the considerable economic value of duck meat, low intramuscular fat content, high polyunsaturated fatty acid content, high protein content, and excellent nutritional value. Although it has many advantages, the product types are monotonous and there are few high-value products. Animal-derived antioxidant peptides are a research hotspot in the field of functional peptides. Natural antioxidants are consistent with people's pursuit of health, but there are few studies on the preparation of antioxidant peptides from poultry meat, especially duck meat.

[0003] After slaughter, muscles undergo a series of physiological and biochemical changes, especially a series of biochemical reactions under the action of endogenous enzymes, which eventually complete the meat maturation process (Huang, Huang et al. 2014). After slaughter, as the maturation time increases, the antioxidant capacity of small peptides in duck meat increases significantly, and the antioxidant capacity of small peptides in duck meat is the strongest after 3 days of maturation (Liu, Chen et al. 2017). Limited degradation of myofibrillar proteins can produce antioxidant peptides.

[0004] In recent years, ultrasound has the advantage of being environmentally friendly (Alarcon-Rojo, Carrillo-Lopez et al. 2019). Ultrasound can improve the tenderness of meat by producing cavitation, mechanical and thermal effects (Kang, Zhang et al. 2021). This is considered to have two possible effects: (I) direct destruction of myofibrils and connective tissue structures (Chang, Wang et al. 2015). (II) release of endogenous enzymes to hydrolyze proteins (Wang, Li et al. 2022). Ultrasound can enrich peptides, and ultrasound-assisted enzymatic hydrolysis can increase the activity of enzymatic hydrolysis products. Summary of the invention

[0005] The purpose of the present invention is to firstly perform ultrasonic treatment on the slaughtered duck meat, then mature the duck meat after ultrasonic treatment for different time periods, extract peptides from the duck meat after ultrasonic treatment as raw material, study the maturation process of duck meat from the aspect of functional activity, determine the content of small peptides in duck meat after ultrasonic synergistic maturation for different time periods, so as to measure the quality change of duck meat at different maturation time periods, and determine the DPPH· scavenging ability, ·OH scavenging ability, FRAP, ABTS of small peptides at different maturation time periods after ultrasonic treatment + Clearing ability. Analyze the functional activity of small peptides during the maturation process and determine the optimal ultrasound conditions and maturation time point.

[0006] In order to solve the above problems, the technical solution adopted by the present invention is as follows:

[0007] A method for enriching antioxidant peptides in duck meat by ultrasound-assisted maturation, which uses Muscovy duck as a raw material, is firstly subjected to ultrasound treatment, and then subjected to maturation treatment to obtain duck meat enriched with antioxidant peptides; wherein the molecular weight of the antioxidant peptides is between 844.2 and 2086 Da, and the sequence length is between 7 and 20 amino acids.

[0008] Furthermore, the surface fascia and fat of the duck breast are removed and the duck breast is cut into pieces. The pieces are vacuum packed and then ultrasonically treated. Finally, the treated pieces are placed in a constant temperature and humidity incubator for post-slaughter maturation to enrich the antioxidant peptides in the duck meat.

[0009] Furthermore, the Muscovy ducks are selected from male Muscovy ducks that are 72 days old.

[0010] Furthermore, the frequency of the ultrasonic treatment is 20 kHz, the power does not exceed 1500 W, and the treatment time is 20 min.

[0011] Furthermore, the power of the ultrasonic treatment was 1050W.

[0012] Furthermore, the ultrasonic treatment process uses a constant temperature water bath with a temperature of 9 to 11°C.

[0013] Furthermore, the temperature of the constant temperature and humidity incubator is 4° C. and the relative humidity is 60%.

[0014] Furthermore, the time for post-slaughter maturation shall not exceed 168 hours.

[0015] Furthermore, the time for post-slaughter maturation is 72h.

[0016] Furthermore, the enriched antioxidant peptide has a molecular weight of 1774.8 Da and a length of 15 amino acids.

[0017] Compared with the prior art, the advantages of this application are:

[0018] 1) Compared with the prior art, the present invention targets the different contents of small peptides and their antioxidant activity in duck meat at different maturation times after slaughter, which can enrich the antioxidant peptides in duck meat, improve the edible and nutritional quality of duck meat products, and promote the deep processing and high-value development of duck meat.

[0019] 2) The present invention clarifies the peptide sequence that exerts antioxidant activity in the Muscovy duck-derived polypeptide after ultrasound-assisted maturation treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1Figure 2 is the effect of different ultrasonic powers on the activity of antioxidant peptides from Muscovy duck; A is the effect of ultrasonic power on the cooking loss of duck meat, B is the effect of ultrasonic power on the shear force of duck meat, C is the effect of ultrasonic power on the content of small peptides in duck meat, D is the effect of ultrasonic power on the ability of small peptides to remove DPPH·, and E is the effect of ultrasonic power on the ability of small peptides to remove ABTS + · ability, F is the effect of ultrasonic power on the antioxidant capacity of small peptides. The data results are expressed as mean ± standard deviation (n = 3), and different capital letters indicate significant differences (p < 0.05).

[0021] Figure 2 This is a graph showing the effect of ultrasonic synergistic maturation on the cooking loss of duck meat; the data results are expressed as mean ± standard deviation (n = 6), different lowercase letters indicate significant differences in different ultrasonic powers at the same maturation time (p < 0.05), and different uppercase letters indicate significant differences in different maturation times under the same ultrasonic power (p < 0.05).

[0022] Figure 3 This is a graph showing the effect of ultrasonic synergistic maturation on the shear force of duck meat; the data results are expressed as mean ± standard deviation (n = 6), different lowercase letters indicate significant differences in different ultrasonic powers at the same maturation time (p < 0.05), and different uppercase letters indicate significant differences in different maturation times under the same ultrasonic power (p < 0.05).

[0023] Figure 4 This is a graph showing the effect of ultrasonic synergistic maturation on the content of small peptides in duck meat; the data results are expressed as mean ± standard deviation (n = 6), different lowercase letters indicate significant differences in different ultrasonic powers at the same maturation time (p < 0.05), and different uppercase letters indicate significant differences in different maturation times under the same ultrasonic power (p < 0.05).

[0024] Figure 5 This is a graph showing the effect of ultrasonic synergistic maturation on the scavenging rate of small peptide DPPH radicals in duck meat; the data results are expressed as mean ± standard deviation (n = 6), different lowercase letters indicate significant differences in different ultrasonic powers at the same maturation time (p < 0.05), and different uppercase letters indicate significant differences in different maturation times under the same ultrasonic power (p < 0.05).

[0025] Figure 6 This is a graph showing the effect of ultrasonic synergistic maturation on the FRAP value of small peptides in duck meat; the data results are expressed as mean ± standard deviation (n = 6), different lowercase letters indicate significant differences in different ultrasonic powers at the same maturation time (p < 0.05), and different uppercase letters indicate significant differences in different maturation times under the same ultrasonic power (p < 0.05).

[0026] Figure 7This is a graph showing the effect of ultrasonic synergistic maturation on the scavenging rate of OH radicals in small peptides in duck meat; the data results are expressed as mean ± standard deviation (n = 6), different lowercase letters indicate significant differences in different ultrasonic powers at the same maturation time (p < 0.05), and different uppercase letters indicate significant differences in different maturation times under the same ultrasonic power (p < 0.05).

[0027] Figure 8 Effect of ultrasound on the maturation of duck meat peptide ABTS + The results of the influence of free radical scavenging rate are shown in the figure; the data results are expressed as mean ± standard deviation (n = 6), different lowercase letters indicate that the same maturation time and different ultrasonic powers have significant differences (p < 0.05), and different uppercase letters indicate that the same ultrasonic power has significant differences in different maturation times (p < 0.05). DETAILED DESCRIPTION

[0028] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with specific embodiments.

[0029] In the following examples, male Muscovy ducks of about 72 days old were selected, the fascia and fat on the surface of each piece of duck breast were removed, and then the duck breasts were divided into 5×5×2cm3 and 30±0.5g pieces along the direction of the muscle fibers. After vacuum packaging, the duck breasts were treated for 20 minutes in an ultrasonic processor with a frequency of 20kHz and a power of 0W and 1050W, respectively. The duck breasts treated with 0W were used as the control group, and the temperature during the ultrasonic treatment was controlled at 10±1°C using a constant temperature water bath. The treated samples were then placed in a constant temperature and humidity incubator at 4°C and 60% relative humidity (RH) for post-slaughter maturation. The water retention, tenderness and other indicators of each group of duck breast samples were measured at six time points of 0h, 6h, 12h, 24h, 72h and 168h after ultrasonication. The measurement methods used in the following examples are as follows:

[0030] Cooking loss was determined by referring to the procedures of Zhu et al. (2021) and Xing et al. (2017). The meat samples were trimmed into 2×3×5 cm 3 The block is weighed as (M1) and placed in a cooking bag. Then, the packaged sample is immersed in a 72°C water bath until the temperature of the electric heating digital probe inserted into the center of the meat sample reaches 70°C, then it is taken out, the surface moisture is wiped off and it is weighed again (M2). The cooking loss is obtained by the following equation: Cooking loss (%) = (M1–M2) / M1×100%.

[0031] The shear force of pork samples was determined according to the method of Wang et al. (2019). The samples were taken out and trimmed into 3×3×5cm 3After the meat is shaped into blocks, it is placed in a cooking bag and immersed in a 72℃ water bath until the thermometer shows that the center temperature of the meat sample reaches 70℃. Then it is taken out and cooled to room temperature under running water. The sample is then trimmed into 1×1×3cm along the direction of the muscle fiber. 3 The shear force was measured using a shear force meter at a shear rate of 5 mm / s.

[0032] Extraction of crude peptides: Refer to the method of Xing et al. (2022) and make some modifications. Take 10g of minced duck meat and put it into a 100mL centrifuge tube, add 40mL of hydrochloric acid (0.01mol / L, pH=2), and homogenize (13000rpm / min, 4 times, each time for 10s). After standing at 4℃ for 2h to allow the soluble substances to be fully dissolved, centrifuge at 4℃, 13000×g for 20min, filter with double gauze to remove insoluble impurities, mix the duck breast extract with three times the volume of 70% (v / v) ethanol, stand at 4℃ for 12h to precipitate large molecular proteins, centrifuge at 4℃, 13000×g for 20min, take the supernatant and perform rotary evaporation at 40℃, freeze-dry at -80℃ after evaporation, and store the dried sample at -20℃.

[0033] Determination of peptide content: The determination of small peptide content was based on the method of Church et al. [7] with slight modifications. The peptide powder was re-dissolved in deionized water and its concentration was adjusted to 2 mg / mL. 100uL of sample was thoroughly mixed with 2mL of o-phthalaldehyde (OPA) reaction solution. After incubation at room temperature in the dark for 2 minutes, the absorbance of each tube was measured by an ELISA reader at a wavelength of 340nm. Preparation method of OPA reaction solution (prepared and used immediately): 80mg OPA was dissolved in 2mL methanol (in the dark), and then 50mL 0.1M borax, 5mL SDS solution (mass concentration 0.2g / mL), and 200μL β-mercaptoethanol were added in sequence, and the volume was adjusted to 100mL with deionized water. Prepare pancreatic casein with a concentration of 0.1-1mg / mL, measure its absorbance to make a standard curve, and calculate the peptide content of the sample.

[0034] Determination of DPPH scavenging rate: The determination of DPPH scavenging rate was carried out according to the method of Wang et al. [7]. The sample was prepared into a solution with a mass concentration of 2 mg / mL using deionized water. 0.5 mL of DPPH solution (dissolved in 100% ethanol) with a concentration of 0.2 mmol / L was taken, and 0.5 mL of crude peptide solution was added. The mixture was shaken evenly. After reacting at room temperature in the dark for 30 minutes, the absorbance of the sample was measured at 517 nm (Asample); the blank group was the absorbance of 0.5 mL 100% ethanol and 0.5 mL peptide solution at 517 nm (Ablank); the control group was the absorbance of 0.5 mL DPPH solution and 0.5 mL 100% ethanol at 517 nm (Acontrol); 0.5 mL 100% ethanol plus 0.5 mL deionized water were used to adjust the concentration to zero. The calculation formula for the scavenging ability of the peptide solution for DPPH is as follows:

[0035] DPPH free radical scavenging rate (%) = [1-(Asample-Ablank) / (Acontrol-

[0036] Ablank)]×100%

[0037] · Determination of OH scavenging rate: · The OH scavenging capacity was determined using a kit. 0.5 mL of the test solution was mixed with 0.2 mL of the substrate application solution and 0.4 mL of the working solution, and then incubated at 37°C for 3 min. After that, 2 mL of the color developer (Griess reagent) was added and kept at ambient conditions for 20 min. Milli-Q water + substrate application solution + color developer was used as the control group, and Milli-Q water + color developer was used as the blank group. The absorbance of each tube was measured at a wavelength of 550 nm using an ELISA reader.

[0038]

[0039] Determination of ferric reducing antioxidant capacity (FRAP) value: FRAP value was determined using a kit, water-soluble vitamin E was used as a standard, and the sample was prepared into a solution with a mass concentration of 2 mg / mL using deionized water. The antioxidant capacity of the sample was expressed as Fe per gram of sample. 2+ The equivalent value of .

[0040] ABTS + · Determination of scavenging capacity: The ABTS+ scavenging value was determined using a kit, with water-soluble vitamin E as the standard. The sample was prepared into a solution with a mass concentration of 2 mg / mL using deionized water. The antioxidant capacity of the sample was expressed as an equivalent value of μmol TE / g per gram of sample.

[0041] Statistical analysis: One-Way ANOVA and Duncan's multiple comparison analysis were performed on the data in this chapter using SAS software. Significant differences were present when p < 0.05. The results are expressed as mean ± standard error (SE).

[0042] The solution was first desalted by OASIS HLB column, and then separated and identified the structure of the antioxidant peptides by Nano-LC-ESI-MS / MS liquid spectrometry.

[0043] Liquid phase conditions: The chromatographic column was Hypersil Gold C18 (75 μm × 8 cm, 3 μm, ); mobile phase A: 97.5% water, 2% acetonitrile and 0.5% formic acid solution, mobile phase B: 9.5% water, 90% acetonitrile and 0.5% formic acid solution; gradient elution: 0-60min (98%-10% A, 2%-90% B), 60-80min (10% A, 90% B); flow rate is 800nL / min, sample volume is 3μL. Mass spectrometry conditions: nanoliter electrospray ion source, ionization mode: ESI (+), ionization voltage is always optimized, usually at 1.2-1.8kV, capillary temperature is 110℃. The primary mass spectrometer is scanned in the Orbitrap, with a scanning range of 550-1800m·z-1 and a resolution of 60,000; the secondary mass spectrometer uses dynamic data dependent scan (DDS). The five highest peaks of the first level were selected for high-energy collision-induced dissociation (HCD) fragment scanning, and the obtained information was subjected to DeNovo sequencing using PEAKS software, and the measured sequence was searched in the Anas library to obtain the most appropriate identification result.

[0044] The artificial synthesis of peptides was completed by Hubei Qiangyao Co., Ltd.

[0045] Example 1

[0046] A method for enriching antioxidant peptides in duck meat by ultrasound-assisted maturation, comprising the following steps:

[0047] (1) The cooking loss and shear force of 0, 150, 300, 450, 600, 750, 900, 1050, 1200, 1350, and 1500 W ultrasound after 0 h of maturation were measured, and the crude peptides of each treatment group were extracted and the peptide content was determined;

[0048] (2) The extracted crude peptides were tested for DPPH scavenging ability, OH scavenging ability, FRAP total antioxidant capacity, and ABTS + · Determination of the removal capacity.

[0049] Example 2

[0050] A method for enriching antioxidant peptides in duck meat by ultrasound-assisted maturation, comprising the following steps:

[0051] (1) The cooking loss and shear force at 0 h post-ultrasound maturation were measured, crude peptides were extracted from duck breast meat at 0 h post-ultrasound maturation, and the peptide content was determined;

[0052] (2) The extracted crude peptides were tested for DPPH scavenging ability, OH scavenging ability, FRAP total antioxidant capacity, and ABTS + · Determination of the removal capacity.

[0053] Example 3

[0054] A method for enriching antioxidant peptides in duck meat by ultrasound-assisted maturation, comprising the following steps:

[0055] (1) The cooking loss and shear force of duck breast meat matured for 6 h after ultrasound were measured, and crude peptides were extracted from duck breast meat matured for 0 h after slaughter and ultrasound, and the peptide content was determined;

[0056] (2) The extracted crude peptides were tested for DPPH scavenging ability, OH scavenging ability, FRAP total antioxidant capacity, and ABTS + · Determination of the removal capacity.

[0057] Example 4

[0058] A method for enriching antioxidant peptides in duck meat by ultrasound-assisted maturation, comprising the following steps:

[0059] (1) The cooking loss and shear force of duck breast meat matured for 12 h after ultrasound were measured, and crude peptides were extracted from duck breast meat matured for 0 h after slaughter and ultrasound, and the peptide content was determined;

[0060] (2) The extracted crude peptides were tested for DPPH scavenging ability, OH scavenging ability, FRAP total antioxidant capacity, and ABTS + · Determination of the removal capacity.

[0061] Example 5

[0062] A method for enriching antioxidant peptides in duck meat by ultrasound-assisted maturation, comprising the following steps:

[0063] (1) The cooking loss and shear force of duck breast meat matured for 24 h after ultrasound were measured, and crude peptides were extracted from duck breast meat matured for 0 h after slaughter and ultrasound, and the peptide content was determined;

[0064] (2) The extracted crude peptides were tested for DPPH scavenging ability, OH scavenging ability, FRAP total antioxidant capacity, and ABTS + · Determination of the removal capacity.

[0065] Example 6

[0066] A method for enriching antioxidant peptides in duck meat by ultrasound-assisted maturation, comprising the following steps:

[0067] (1) The cooking loss and shear force of duck breast meat matured for 72 h after ultrasound were measured, and crude peptides were extracted from duck breast meat matured for 0 h after slaughter and ultrasound, and the peptide content was determined;

[0068] (2) The extracted crude peptides were tested for DPPH scavenging ability, OH scavenging ability, FRAP total antioxidant capacity, and ABTS + · Determination of the removal capacity.

[0069] Example 7

[0070] A method for processing antioxidant peptides in duck meat by ultrasound-assisted maturation, comprising the following steps:

[0071] (1) The cooking loss and shear force of duck breast meat matured for 168 h after ultrasound were measured, and crude peptides were extracted from duck breast meat matured for 0 h after slaughter and ultrasound, and the peptide content was determined;

[0072] (2) The extracted crude peptides were tested for DPPH scavenging ability, OH scavenging ability, FRAP total antioxidant capacity, and ABTS + · Determination of the removal capacity.

[0073] Effects of different ultrasonic powers on the activity of antioxidant peptides from Muscovy duck Figure 1 As shown in the results, ultrasound can significantly reduce the cooking loss of duck breast meat (P<0.05), and ultrasound can significantly reduce the shear force of duck breast meat (P<0.05). With the increase of ultrasonic power, the content of small peptides in duck breast meat increased significantly (P<0.05), reaching the maximum value at 1500W, but there was no significant difference between the peptide content at 1500W and that at 1050W (P>0.05); and the antioxidant capacity of small peptides was the strongest when the ultrasonic power was 1050W. Therefore, the ultrasonic power of 1050W was selected for subsequent research.

[0074] Effect of ultrasound-assisted ripening on cooking loss of duck meat, e.g. Figure 2 As shown in the figure: Under the same ultrasonic power, as the post-slaughter maturation time increases, the cooking loss of duck breast meat decreases first and then increases, reaching the maximum value at 168h. This may be due to the weakening of the ability of myofibrils to bind water during the post-slaughter maturation period. Under the same maturation time, ultrasound can reduce the cooking loss of duck meat and improve water retention, which is conducive to the improvement of the quality of duck breast meat.

[0075] Effects of ultrasound synergistic ripening on shear stress in duck meat, e.g. Figure 3As shown in the figure: Under the same ultrasonic power, the shear force of duck breast meat tends to decrease slowly with the extension of post-slaughter maturation time. The shear force value decreases with the extension of post-slaughter maturation time, which may be caused by the degradation of myofibrillar proteins in duck breast meat by the endogenous enzyme system during the post-slaughter maturation process; under the same maturation time, ultrasound can reduce the shear force of duck breast meat, which may be due to the increase in the release of endogenous proteases under the action of ultrasound, thereby promoting protein hydrolysis and making the duck breast meat tender.

[0076] Effects of ultrasound-assisted ripening on the content of small peptides in duck meat, such as Figure 4 The results show that the trend of small peptide content in duck breast is similar to that of free amino acids. At 0-6h, the content of small peptides decreased significantly (P < 0.05), and then with the extension of maturation time, the content of small peptides increased, reaching the maximum value at 72h of maturation. At the same maturation time, the peptide content of the ultrasound group was higher than that of the non-ultrasound group.

[0077] Effects of ultrasound-assisted ripening on the DPPH radical scavenging ability of small peptides in duck meat, such as Figure 5 As shown in the figure: Under the same ultrasonic power, with the extension of maturation time, the DPPH scavenging ability of small peptides showed a trend of first decreasing, then increasing, and then decreasing, reaching the maximum value at 72h, which was 47% in the ultrasonic group and 40% in the non-ultrasonic group. Under the same maturation time, the DPPH scavenging ability of the ultrasonic group was significantly improved compared with the non-ultrasonic group (P < 0.05), and it increased by 7% at 72h of maturation.

[0078] Effects of ultrasound-assisted ripening on the OH radical scavenging ability of small peptides in duck meat, such as Figure 7 As shown in the figure: Under the same ultrasound power, with the extension of maturation time, the OH free radical scavenging ability of small peptides showed a trend of first decreasing, then increasing, and then decreasing, reaching the maximum value at 72h, which was 31.71% in the ultrasound group and 28.36% in the non-ultrasound group. Under the same maturation time, the OH scavenging ability of the ultrasound group was significantly improved compared with the non-ultrasound group (P < 0.05), and it increased by 3.35% at 72h of maturation.

[0079] Effect of ultrasound-assisted ripening on the FRAP value of total antioxidant capacity of small peptides in duck meat, such as Figure 6 As shown in the figure: Under the same ultrasonic power, with the extension of maturation time, the FRAP value of small peptides showed a trend of first decreasing, then increasing, and then decreasing, reaching the maximum value at 72h, which was 25.48μmol Fe2+ / g in the ultrasonic group and 21.48μmol Fe2+ / g in the non-ultrasonic group. Under the same maturation time, the FRAP value of the ultrasonic group was significantly higher than that of the non-ultrasonic group (P<0.05), and it increased by 4μmol Fe2+ / g at 72h of maturation. Therefore, ultrasound synergistic maturation can significantly improve the antioxidant capacity of duck meat crude peptides.

[0080] Effect of ultrasound-assisted ripening on small peptide ABTS in duck meat + The influence of free radical scavenging ability, such as Figure 8 As shown: At the same ultrasonic power, as the maturation time increases, the ABTS of small peptides + The free radical scavenging capacity showed a trend of first decreasing, then increasing, and then decreasing, reaching the maximum value at 72h, which was 211.23μmol TE / g in the ultrasound group and 192.37μmol TE / g in the non-ultrasound group. Under the same maturation time, the ABTS+· scavenging capacity of the ultrasound group was significantly improved compared with the non-ultrasound group (P<0.05), and increased by 18.86μmol TE / g at 72h of maturation.

[0081] In summary, when the ultrasonic conditions were ultrasonic frequency of 20kHz, ultrasonic power of 1050W, ultrasonic time of 20min, and maturation time of 72h, the duck meat peptide content was the highest and the antioxidant peptide activity produced was the strongest.

[0082] Example 7

[0083] In this example, the sequence of the antioxidant peptide in the ultrasonically matured 3d crude peptide was identified, and it was screened and then artificially synthesized to verify its antioxidant activity.

[0084] A total of 87 peptide sequences were identified, and those with -10lgP values ​​greater than 20 were considered credible peptides. According to the -10lgP value and intensity value, 9 peptide sequences with high credibility and large intensity values ​​were screened out as shown in Table 1. The molecular weight with high antioxidant activity was between 844.24-2086.06Da, and the sequence length was between 7-20 amino acids. The 9 peptides with high intensity and high confidence were further characterized for peptide features.

[0085] After artificial synthesis, the antioxidant activities of 9 peptides were measured, as shown in Table 1 , among which ENHHCCC had the strongest antioxidant activity.

[0086] Table 1: 9 peptide sequences with strong antioxidant activity isolated from Muscovy duck peptides

[0087]

[0088]

[0089] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for enriching antioxidant peptides in duck meat by ultrasound-assisted maturation, characterized in that: The method uses Muscovy duck as a raw material, removes the surface fascia and fat from duck breast meat, divides the duck breast meat into meat pieces, vacuum packs the meat pieces and then performs ultrasonic treatment, and finally places the treated meat pieces in a constant temperature and humidity incubator for post-slaughter maturation to obtain duck meat enriched with antioxidant peptides; wherein the molecular weight of the antioxidant peptides is between 844.24 and 2086.07 Da, and the sequence length is between 7 and 20 amino acids; the Muscovy duck is a male Muscovy duck aged 72 days; the frequency of the ultrasonic treatment is 20 kHz, the power does not exceed 1500 W, and the treatment time is 20 minutes; the enriched antioxidant peptides are AMGIMNSFVNDIFER, GHYTEGAELVDSVLDVVRK, AVFVDLEPTVIDEVR, TIGGGDDSFNTFFSETGAGK, GVVDSEDLPLNISR, TTPSYVAFTDTER, ENHHCCC, ELEAELEDER, and LFIGGLSFETTEESLR.

2. The method for enriching antioxidant peptides in duck meat by ultrasound-assisted maturation according to claim 1, characterized in that: The power of the ultrasonic treatment was 1050W.

3. The method for enriching antioxidant peptides in duck meat by ultrasound-assisted maturation according to claim 1, characterized in that: The ultrasonic treatment process uses a constant temperature water bath with a temperature of 9 to 11°C.

4. The method for enriching antioxidant peptides in duck meat by ultrasound-assisted maturation according to claim 1, characterized in that: The temperature of the constant temperature and humidity incubator is 4°C; the relative humidity is 60%.

5. The method for enriching antioxidant peptides in duck meat by ultrasound-assisted maturation according to claim 1, characterized in that: The time for post-slaughter maturation shall not exceed 168 hours.

6. The method for enriching antioxidant peptides in duck meat by ultrasound-assisted maturation according to claim 5, characterized in that: The time for post-slaughter maturation is 72 hours.

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