Nutrient-enriched healthy duck eggs as well as production method and pickling method thereof

Abstract

The invention relates to the technical field of poultry breeding and poultry egg production, in particular to nutrient-enriched healthy duck eggs as well as a production method and a pickling method thereof. According to the production method of the nutrition-enriched healthy duck eggs provided by the invention, healthy Shaoxing ducks are selected as the laying ducks, the contents of unsaturated fatty acid, selenium and xanthophyll in the duck eggs can be pertinently increased by feeding the duck eggs with the nutrition-enriched feed additive and the probiotics, and the proportion of EPA / DHA is relatively high. According to the pickling method of the nutrition-fortified healthy duck eggs, the prepared nutrition-fortified fresh duck eggs serve as raw materials, the pickling process is optimized, degradation of nutrient substances is effectively reduced, the retention rate of selenium, xanthophyll and polyunsaturated fatty acid in the salted duck eggs is high, meanwhile, the salted duck eggs have good pickling quality, and the salted duck eggs are rich in nutrition. The prepared salted duck eggs are high in oil yield and appropriate in salt content.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of poultry farming and egg production, in particular to a kind of nutritionally enhanced healthy duck egg and its production method and pickling method. BACKGROUND

[0002] Duck egg is rich in protein, essential fatty acids, minerals and vitamins, and is a traditional high-nutrition food. Duck eggs can be eaten in many ways, and through the use of salt pickling process, salted duck eggs have the advantages of convenient eating and storage, and are widely welcomed by consumers. With the growing demand for functional health products, the technology of enriching nutritionally enhanced ingredients through feed additives in duck egg production has become a research hotspot.

[0003] Polyunsaturated fatty acids, lutein and selenium are very important for human health, and eating duck eggs rich in polyunsaturated fatty acids, lutein and selenium can well fill the nutritional gap in diet. Compared with chicken eggs, duck eggs have higher fat content and yolk proportion, and are ideal carriers for fat-soluble nutrients. Duck eggs are convenient to eat and easy to obtain. A large number of studies have shown that, compared with other polyunsaturated fatty acids, EPA has the effect of helping to reduce cholesterol and triglyceride content and promoting the metabolism of saturated fatty acids in the body. However, the existing production and pickling process of duck eggs enriched with nutritionally enhanced ingredients through feed additives has the following defects: polyunsaturated fatty acids and lutein are easily oxidized, the utilization rate of selenium is not high, ordinary feeding methods are difficult to effectively increase the content of polyunsaturated fatty acids, lutein and selenium in duck eggs, the proportion of EPA in polyunsaturated fatty acids in duck eggs is low, and the above nutrients are further lost more after duck eggs are made into salted duck eggs. Based on this, the present application aims to study the production method and pickling method of duck eggs to solve the above problems. SUMMARY

[0004] In view of the deficiencies of the prior art, the present application aims to provide a kind of nutritionally enhanced healthy duck egg and its production method and pickling method, duck egg produced by the method is rich in polyunsaturated fatty acids, lutein and selenium, and the proportion of EPA / DHA is higher, the pickling method provided by the present application has high yolk oil exudation rate, moderate saltiness, and polyunsaturated fatty acids, lutein and selenium are not easy to lose.

[0005] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows: A production method of nutritionally enhanced healthy duck egg, comprising the following steps: S1, selecting a semi-open duck house in a mountainous area with south-facing water, high dryness and good drainage; S2, selecting healthy and weight-standard 120-150 day-old laying Shaoxing ducks; S3, adding 1.5-2.5% of the nutritional fortification feed additive and 0.1-0.2% of the probiotics in the basal feed for feeding, feeding in a fixed time and quantity, ensuring sufficient clean drinking water throughout the process, collecting the duck eggs produced after feeding the nutritional fortification feed additive for 21 days continuously as the nutritional fortification duck eggs; the probiotics are Bacillus subtilis and Bifidobacterium animalis lactis Bacillus subtilis DE111 and Bifidobacterium animalis lactis Bifidobacterium animalis subsp. Lactis BB-12 ; The preparation method of the nutritional fortification feed additive comprises the following steps: (1) obtaining flaxseed oil and flaxseed meal by cold pressing of flaxseed, and obtaining schizochytrium oil and schizochytrium meal by cold pressing of schizochytrium powder; (2) dissolving 25-28 parts of flaxseed oil, 12-15 parts of schizochytrium oil and 4-6 parts of lutein ester at 55-65°C to obtain an oil phase; adding 33-37 parts of selenium-rich yeast powder, 13-15 parts of malt dextrin and 2-4 parts of HPMC into 280-320 parts of water, and homogenizing to obtain an aqueous phase; (3) slowly adding the oil phase into the aqueous phase, homogenizing to form a stable emulsion, and then performing spray drying to obtain microcapsules; (4) adding 7-9 parts of Eudragit L30D-55, 4-6 parts of betaine hydrochloride, 1.5-2.5 parts of vitamin E and 0.5-1.5 parts of HPMC into water to prepare a coating liquid with a solid content of 25-30%; (5) coating the microcapsules in a fluidized bed to obtain composite nutritional microcapsules; (6) mixing 70-80 parts of flaxseed meal and 20-30 parts of schizochytrium meal to obtain dry materials, and then adding the dry materials into fermentation bacteria for fermentation to obtain a carrier; (7) mixing the composite nutritional microcapsules and the carrier to obtain the nutritional fortification feed additive.

[0006] The nutritional fortification feed additive provided in the application obtains oil and meal from flaxseed powder and schizochytrium powder respectively by cold pressing process, and prepares the nutritional fortification feed additive by adopting the oil phase microcapsule structure and the fermentation process of meal. The preparation of the composite nutritional microcapsules adopts flaxseed oil, schizochytrium oil and lutein ester as the oil phase core, adopts selenium-rich yeast powder, malt dextrin and HPMC as the aqueous phase wall material, and is coated by spray drying and coating liquid in sequence. The composite nutritional microcapsule structure solves the problems of oxidation inactivation of unsaturated fatty acids, light and heat instability of lutein and low release efficiency in the intestinal tract. The flaxseed meal and schizochytrium meal remaining after pressing flaxseed oil and schizochytrium oil are selected and fermented by probiotics, and the texture is uniform, which can be used as a carrier of the composite nutritional microcapsule. The flaxseed meal and schizochytrium meal are rich in protein and polysaccharide, and the small molecule active peptides and prebiotics produced by fermentation can promote lipid metabolism and nutrient transport of laying ducks, promote absorption and optimize the proportion of polyunsaturated fatty acids, and the residual unsaturated fatty acids can improve the utilization rate of raw materials.

[0007] The complex nutritional microcapsule adopts a specific proportion of flaxseed oil and schizochytrium oil as the oil phase core, and adds fat-soluble lutein ester, which enhances the antioxidant property of the oil phase and strengthens the lutein content; rich selenium yeast powder, malt dextrin and HPMC are used as the wall material, wherein the rich selenium yeast powder serves as a selenium nutritional enhancer while having emulsifying and film-forming properties, the malt dextrin forms a protein polysaccharide wall material skeleton together with the protein in the rich selenium yeast powder, and the HPMC is added to improve the water phase stability and enhance the wall material; further, Eudragit L30D-55 enteric coating is used to embed vitamin E and betaine hydrochloride, the enteric coating reduces the release of the core components in the stomach acid, vitamin E improves the antioxidant property of the microcapsule, betaine hydrochloride improves the feed intake of duck eggs and the utilization rate of feed additives, provides active methyl to promote fat metabolism, and HPMC improves the film-forming property and coating stability, the test results show that the method of the present application effectively improves the enrichment of polyunsaturated fatty acids, lutein ester and selenium in duck eggs, and helps to improve the EPA / DHA ratio.

[0008] Further, in the preparation method of the nutritional fortification feed additive, the homogenization treatment in step (2) and step (3) is 5-10 min at 10000-15000 rpm.

[0009] Further, in the preparation method of the nutritional fortification feed additive, the spray drying inlet temperature in step (3) is 150-160℃, and the outlet temperature is 60-70℃.

[0010] Further, in the preparation method of the nutritional fortification feed additive, the coating method in step (5) is to preheat the microcapsule to 38-40℃, spray the coating liquid, the spraying rate is 6-8 ml / min, the inlet temperature is 65-70℃, the atomization pressure is 1.2-1.5 bar, and the coating weight gain is 8-15% to prepare the complex nutritional microcapsule.

[0011] Further, in the preparation method of the nutritional fortification feed additive, the fermentation method in step (6) is to mix the flaxseed meal and the schizochytrium meal to obtain dry materials, add 1-2% of the fermentation bacteria by weight of the dry materials, adjust the water content of the dry materials to 40-45% by adding water, and ferment at a temperature of 33-36℃ and a humidity of 80-85% for 24-48 hours; the fermentation product is dried to a water content of less than 5%, crushed and sieved through an 80-mesh sieve to obtain the carrier.

[0012] Further, in the preparation method of the nutritional fortification feed additive, the fermentation bacteria used in the fermentation method in step (6) are Lactobacillus plantarum Lactobacillus plantarum EM-12 and Pediococcus acidilactici Pediococcus acidilactici HEW-AP27 Bacillus subtilis DE111 mixed in a ratio of 3:1.

[0013] The application also provides a nutritionally fortified healthy duck egg, which is produced according to the above method.

[0014] The application also provides a pickling method of the nutritionally fortified healthy duck egg, which comprises the following steps. (1) Raw material receiving and pretreatment: fresh, undamaged and qualified duck eggs according to the quality standards are collected, and the duck eggs are cleaned, disinfected and air-dried, wherein the duck eggs are the nutritionally fortified healthy duck eggs described above; (2) Pickling: the dried duck eggs are first soaked in a coating liquid for 5-10 minutes, then excess solution is drained off, and the duck eggs are dried and soaked in a 0.5% calcium chloride solution for 5-10 minutes, then excess solution is drained off, and the duck eggs are dried; the treated duck eggs are put into a pickling jar, pickling liquid is injected, the jar is sealed, and the jar is placed in a cool and ventilated place for pickling for 15-30 days; wherein the coating liquid is prepared by dissolving chitosan and sodium alginate in a 2-4% acetic acid solution to prepare a solution with a chitosan concentration of 1-2% and a sodium alginate concentration of 1-2%, and then adding 0.1-0.2% vitamin E acetate and mixing uniformly; (3) Taking out, cleaning and drying: after pickling is completed, the duck eggs are taken out, the surface salt frost and impurities are washed off with flowing clean water, and then the duck eggs are put into a drying tunnel to remove the surface moisture of the duck eggs; (4) Packaging, sealing and sterilization: the pickled duck eggs are vacuum packaged, and then are put into a horizontal high-pressure steam sterilization pot for sterilization at 121°C and 0.15 MPa for 15-20 minutes, and then are cooled to room temperature to obtain the nutritionally fortified healthy duck eggs.

[0015] The pickling method provided by the application has the advantages that the duck eggs are soaked in the coating liquid containing chitosan, sodium alginate and vitamin E acetate before pickling, the chitosan molecular chain has a large number of cationic groups, can be adsorbed onto the eggshell to form a film in a humid environment, the sodium alginate is an anionic polysaccharide, can quickly form a gel in the presence of calcium chloride to improve the strength, and can encapsulate the vitamin E acetate in the gel film; the chitosan also has a certain hydrophilicity, which can help Na + and Cl - in the pickling liquid to enter the duck eggs to ensure the pickling quality, and finally effectively reduces the degradation of nutrients, so that the selenium, lutein and polyunsaturated fatty acid retention rates in the salted duck eggs are high, the pickling quality is good, the salted duck eggs have a high oil out rate and an appropriate salt content.

[0016] Further, in step (2), the formula of the pickling liquid is: 20-25% NaCl, 0.3-0.5% whey protein peptide and 0.05-0.1% compound spice, and the rest is water; wherein the compound spice is star anise, cassia bark and Sichuan pepper at a ratio of 3:3:2.

[0017] Further, in step (1), the cleaning and disinfecting method is to use an automatic egg loading machine to transport the duck eggs from the egg basket to the conveyor belt system, and then use circulating water and detergent for preliminary cleaning, high-pressure water for rinsing, and pure water for rinsing. During the cleaning process, a soft-bristle brush roller is provided to assist in removing surface dirt. After cleaning, the duck eggs enter a sodium hypochlorite or ozone water spraying disinfection area to effectively kill surface microorganisms. After rinsing the residual disinfectant with pure water, the duck eggs are rinsed with 0.5-1% sodium ascorbate solution for 1-2 minutes. The dried duck eggs are then dried in a hot air drying channel to remove surface moisture, and the drying time is controlled within 2-5 minutes.

[0018] Compared with the prior art, the beneficial effects of the present application are: 1. The production method of the nutritionally enhanced healthy duck eggs provided by the present application selects healthy laying Shaoxing ducks as egg ducks, and uses nutritionally enhanced feed additives and probiotics to feed the ducks to specifically increase the content of unsaturated fatty acids, selenium and lutein in the duck eggs, and the ratio of EPA / DHA is relatively high.

[0019] 2. The curing method of the nutritionally enhanced healthy duck eggs provided by the present application uses the nutritionally enhanced fresh duck eggs prepared above as raw materials to optimize the curing process, effectively reduces the degradation of nutrients, and has a higher retention rate of selenium, lutein and polyunsaturated fatty acids in the cured duck eggs, while having a better cured quality, a high oil release rate and an appropriate salt content. DETAILED DESCRIPTION

[0020] The technical solutions of the present application will be described clearly and completely below in combination with the embodiments of the present application. The described embodiments are only some of the embodiments of the present application, not all the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0021] The methods are all conventional methods unless otherwise specified, and the raw materials can be obtained from public commercial channels unless otherwise specified.

[0022] Example 1: Production of nutritionally enhanced duck eggs The test research selects the mountain gentle slope (gradient < 10°) with south water, high dry sunny and good drainage, establishes a semi-open duck house, selects healthy and standard weight 120-150 day old laying Shaoxing ducks, divides the egg ducks into 8 groups, including 3 test groups and 5 control groups, 50 egg ducks in each group, the test grouping is shown in Table 1, the test period is 40 days, during the test, the ducks are fed at 6:00, 11:00 and 17:00 every day, the average daily feeding amount of each duck is 130 g to avoid overfeeding, the clean drinking water is ensured throughout the whole process, the light time should be stable at 16 hours every day, the indoor temperature should be maintained between 8-30℃, if it is lower or higher than the standard, the insulation or cooling measures should be taken, the management should be less closed and more open to promote the movement, the operation procedures should be kept relatively stable, all sudden stimulation to cause stress reaction should be avoided, the influence of the climate change should be paid attention to, and the relative stability of the small climate in the duck house should be maintained; Table 1: Test grouping and diet composition

[0023] The basic feed formula comprises 51.15% of corn, 21.8% of soybean meal, 5% of rapeseed meal, 9.8% of secondary powder, 1.2% of calcium hydrogen phosphate, 9.2% of stone powder, 0.3% of salt, 0.35% of methionine and 1.2% of premix; the premix (per kg) comprises 835000 IU of vitamin A, 228000 IU of vitamin D3, 165 mg of vitamin K3, 155 mg of vitamin B1, 375 mg of vitamin B2, 200 mg of vitamin B6, 915 ug of vitamin B12, 1850 mg of vitamin C, 2080 mg of niacin, 580 mg of pantothenic acid, 75 mg of folic acid, 7 mg of biotin, 103500 mg of choline chloride, 5520 mg of iron, 76 mg of iodine, 425 mg of copper, 5640 mg of manganese and 5175 mg of zinc; The probiotics are bacillus subtilis and animal bifidobacterium lactis in a weight ratio of 2:1; Bifidobacterium animalis subsp. Lactis BB-12 Lactobacillus plantarum EM-12 ; The feed additive I is prepared by the following method: (1) take the flaxseed powder and the schizochytrium sp. powder, the flaxseed oil and the flaxseed meal are obtained by cold pressing of the flaxseed powder, and the schizochytrium sp. oil and the schizochytrium sp. meal are obtained by cold pressing of the schizochytrium sp. powder; the cold pressing method is that the flaxseed powder (or the schizochytrium sp. powder) is dried to a water content of less than 5%, a double-screw low-temperature oil press is used for pressing, the inlet temperature is 40℃, the crude oil obtained by cold pressing is filtered to obtain the flaxseed oil (or the schizochytrium sp. oil) and the flaxseed residue (or the schizochytrium sp. residue), and the flaxseed residue (or the schizochytrium sp. residue) is mixed with the pressed meal and then pulverized as the flaxseed meal (or the schizochytrium sp. meal); ​(2) Dissolve 25 parts of linseed oil, 12 parts of Schizochytrium oil and 4 parts of lutein ester at 60°C, add 35 parts of selenium-rich yeast powder, 14 parts of malt dextrin (DE value of 10) and 3 parts of HPMC (E5 grade) into 300 parts of water, and homogenize and emulsify at 10,000 rpm for 5 min to obtain an aqueous phase; (3) Slowly add the oil phase into the aqueous phase, and homogenize at high speed at 15,000 rpm for 10 min to form a stable emulsion, and spray dry the emulsion at an inlet temperature of 150°C and an outlet temperature of 60°C to obtain microcapsules; (4) Prepare a coating liquid with a solid content of 28% by adding water to 7 parts of Eudragit L30D-55, 4 parts of betaine hydrochloride, 1.5 parts of vitamin E and 0.5 part of HPMC (E5 grade); (5) Place the microcapsules in a fluidized bed, preheat to 38°C, spray the coating liquid, the spraying rate is 6 ml / min, the inlet temperature is 65°C, the atomization pressure is 1.2 bar, and the coating weight gain is 8% to prepare the composite nutrient microcapsules; (6) Mix 70 parts of linseed meal and 30 parts of Schizochytrium meal to obtain dry mixture, add 1.5% of fermentation bacteria based on the weight of the dry mixture, add water to adjust the moisture content of the dry mixture to 40%, and ferment at a temperature of 35°C and a humidity of 80% for 24 hours; stir every 12 hours, dry the fermentation product to a moisture content of less than 5%, crush and pass through an 80-mesh sieve as a carrier, and the fermentation bacteria are Lactobacillus plantarum, Pediococcus acidilactici Pediococcus acidilactici HEW-AP27 , Pediococcus acidilactici Lactobacillus plantarum EM-12 in a ratio of 3:1; (7) Mix the composite nutrient microcapsules with the carrier to obtain the nutrient fortified feed additive.

[0024] The feed additive II is prepared by the following method: (1) Take linseed powder and Schizochytrium powder, the linseed is cold-pressed to obtain linseed oil and linseed meal, and the Schizochytrium powder is cold-pressed to obtain Schizochytrium oil and Schizochytrium meal, and the cold-pressing method is the same as that of the preparation of the feed additive I; (2) Dissolve 28 parts of linseed oil, 15 parts of Schizochytrium oil and 6 parts of lutein ester at 60°C, add 37 parts of selenium-rich yeast powder, 15 parts of malt dextrin (DE value of 10) and 3 parts of HPMC (E5 grade) into 300 parts of water, and homogenize and emulsify at 10,000 rpm for 5 min to obtain an aqueous phase; (3) Slowly add the oil phase into the aqueous phase, and homogenize at high speed at 15,000 rpm for 10 min to form a stable emulsion, and spray dry the emulsion at an inlet temperature of 160°C and an outlet temperature of 70°C to obtain microcapsules; (4) Take Eudragit L30D-55 9 parts, betaine hydrochloride 6 parts, vitamin E 2.5 parts and HPMC (E5 grade) 1.5 parts, and prepare a coating liquid with a solid content of 25% by adding water; (5) Place the microcapsules in the fluidized bed, preheat to 38°C, spray the coating liquid, the spraying rate is 8 ml / min, the inlet air temperature is 70°C, the atomization pressure is 1.2 bar, and the coating weight gain is 15% to prepare the composite nutritional microcapsules; (6) Mix 80 parts of linseed meal and 20 parts of schizochytrium meal to obtain dry mixture, add 1.5% of fermentation bacteria based on the weight of the dry mixture, add water to adjust the moisture content of the dry material to 40%, ferment at a temperature of 35°C and a humidity of 80% for 48 hours, stir every 12 hours, dry the fermentation product to a moisture content of less than 5%, and then crush and pass through an 80-mesh sieve to obtain the carrier. The fermentation bacteria are Lactobacillus plantarum Pediococcus acidilactici HEW-AP27 , Pediococcus acidilactici Lactobacillus plantarum EM-12 Mix according to a ratio of 3:1; (7) Mix the composite nutritional microcapsules with the carrier to obtain the nutritional feed additive.

[0025] The feed additive III is prepared by the following method: (1) Take linseed powder and schizochytrium powder. Linseed is cold-pressed to obtain linseed oil and linseed meal, and schizochytrium powder is cold-pressed to obtain schizochytrium oil and schizochytrium meal. The cold-pressing method is the same as that for the preparation of the feed additive I; (2) Dissolve 26 parts of linseed oil, 13 parts of schizochytrium oil, and 5 parts of lutein ester at 60°C by stirring, add 37 parts of selenium-enriched yeast powder, 14 parts of malt dextrin (with a DE value of 10), and 3 parts of HPMC (E5 grade) to 300 parts of water, and homogenize and emulsify at 10,000 rpm for 5 min to obtain an aqueous phase; (3) Slowly add the oil phase to the aqueous phase, and homogenize at a high speed of 15,000 rpm for 10 min to form a stable emulsion. Spray dry the emulsion at an inlet air temperature of 155°C and an outlet air temperature of 65°C to obtain microcapsules; (4) Take Eudragit L30D-55 9 parts, betaine hydrochloride 6 parts, vitamin E 2.5 parts and HPMC (E5 grade) 1.5 parts, and prepare a coating liquid with a solid content of 25% by adding water; (5) Place the microcapsules in the fluidized bed, preheat to 38°C, spray the coating liquid, the spraying rate is 8 ml / min, the inlet air temperature is 70°C, the atomization pressure is 1.2 bar, and the coating weight gain is 15% to prepare the composite nutritional microcapsules; (6) Mix 75 parts of linseed meal and 25 parts of Schizochytrium sp. meal to obtain dry mixture, add fermentation bacteria at 1.5% of the weight of the dry mixture, add water to adjust the moisture content of the dry mixture to 40%, and ferment at a temperature of 35°C and a humidity of 80% for 36 hours; stir every 12 hours, dry the fermentation product to a moisture content of less than 5%, crush and sieve through an 80-mesh sieve to obtain the carrier, and the fermentation bacteria are Lactobacillus plantarum and Pediococcus acidilactici Pediococcus acidilactici HEW-AP27 , Pediococcus acidilactici Lactobacillus plantarum EM-12 at a ratio of 3:1; (7) Mix the compound nutritional microcapsules with the carrier to obtain the nutritionally fortified feed additive.

[0026] The feed additive IV is prepared by directly mixing 101 parts of linseed powder, 38 parts of Schizochytrium sp. powder, 5 parts of lutein ester, 37 parts of selenium-rich yeast powder, 1.5 parts of vitamin E, 3.7 parts of betaine hydrochloride, and 24.6 parts of soybean meal.

[0027] The feed additive V is prepared by the following method: (1) Take linseed powder and Schizochytrium sp. powder, and obtain linseed oil and linseed meal by cold pressing of the linseed, and obtain Schizochytrium sp. oil and Schizochytrium sp. meal by cold pressing of the Schizochytrium sp. powder, and the cold pressing method is the same as that for the preparation of the feed additive I; (2) Mix 26 parts of linseed oil, 13 parts of Schizochytrium sp. oil, 5 parts of lutein ester, 37 parts of selenium-rich yeast powder, and 17 parts of HPMC (E5 grade), and then add water to prepare a soft material with a moisture content of 25%, sieve through a 20-mesh sieve, and dry at 50°C to obtain the product; (3) Take 8 parts of Eudragit L30D-55, 5 parts of betaine hydrochloride, 2 parts of vitamin E, and 1 part of HPMC (E5 grade), and add water to prepare a coating liquid with a solid content of 25%; (4) Place the granules in a fluidized bed and preheat to 38°C, spray the coating liquid at a rate of 7 ml / min, the air inlet temperature is 68°C, the atomization pressure is 1.2 bar, and the coating weight gain is 12% to obtain the coated granules; (5) Mix 75 parts of linseed meal and 25 parts of Schizochytrium sp. meal to obtain dry mixture, add fermentation bacteria at 1.5% of the weight of the dry mixture, add water to adjust the moisture content of the dry mixture to 40%, and ferment at a temperature of 35°C and a humidity of 80% for 36 hours; stir every 12 hours, dry the fermentation product to a moisture content of less than 5%, crush and sieve through an 80-mesh sieve to obtain the carrier, and the fermentation bacteria are Lactobacillus plantarum and Pediococcus acidilactici Pediococcus acidilactici HEW-AP27 , Pediococcus acidilactici ​ at a ratio of 3:1; (6) Mix the coated granules with the carrier to obtain the nutritionally fortified feed additive.

[0028] The feed additive VI is prepared by the following method: according to the method of the feed additive III, except that the carrier of the feed additive step (6) is not subjected to fermentation treatment, and the 75 parts of linseed meal and 25 parts of schizochytrium meal are directly mixed to obtain the feed additive VI. The fresh duck eggs produced before 3 days of the end of the feeding test of the test group and the control group were collected, and the quality of the produced duck eggs was checked: egg weight, yolk ratio, eggshell strength and thickness, wherein the egg weight, yolk ratio, eggshell strength and thickness were carried out according to the provisions in NY / T823-2004, and the results are shown in Table 2; the DHA, ALA and EPA content, selenium and lutein content of the produced duck eggs were detected, wherein the lutein was determined according to the method in GB5009.248-2016; the selenium content was carried out according to the method in GB 5009.93-2017; the DHA, ALA and EPA content were determined according to the method in NY / T2068-2011, and the determination results are shown in Table 3 as follows: Table 2: Test results of duck egg quality

[0029] As can be seen from the above, compared with the control group 1, the duck eggs produced by the test groups 1-3 have increased egg weight and yolk ratio, and slightly decreased eggshell strength and eggshell thickness. Combined with the control group 2 and the test group 3, it can be seen that the control group 2 does not add probiotics, and the produced duck eggs have decreased egg weight, yolk ratio, eggshell strength and eggshell thickness. Combined with the control groups 3-5 and the test group 3, it can be seen that the control groups 3-5 have decreased egg weight, and the yolk ratio, eggshell strength and eggshell thickness have little difference.

[0030] Table 3: Detection data of unsaturated fatty acids, selenium and lutein of duck eggs

[0031] From the above, compared with the control group 1, the contents of lutein, selenium, DHA, ALA and EPA in the duck eggs produced by the test groups 1-3 of the present application increased significantly. In combination with the control group 2 and the test group 3, it can be seen that the control group 2 did not add probiotics, and the contents of lutein, selenium, DHA and EPA in the duck eggs decreased, the content of ALA increased, and the ratio of EPA / DHA decreased, indicating that the above-mentioned probiotics can improve the absorption and enrichment of the above-mentioned nutrients in duck eggs after adding the nutritional feed additive; in combination with the control groups 3-5 and the test group 3, the preparation method of the feed additive has a significant effect on the enrichment of nutrients in duck eggs. The control group 3 investigated the conventional mixing of various nutrients, and the results showed that the feed additive prepared by this method was not conducive to the enrichment of lutein, selenium and polyunsaturated fatty acids in duck eggs. The control group 4 investigated the preparation of the feed additive by using the wet granulation + coating method, and the results showed that the feed additive prepared by this method was not as good as the test group 3 in the enrichment of lutein, selenium and polyunsaturated fatty acids in duck eggs, but overall better than the control group 3. The control group 5 investigated the use of flaxseed meal and schizochytrium meal as carriers without fermentation, and the results showed that the feed additive prepared by this method was especially not conducive to the enrichment of EPA in duck eggs, and the ratio of EPA / DHA was low.

[0032] Example 2: Pickling of salted duck eggs using nutritionally fortified duck eggs 1. Raw material receiving and pretreatment: duck eggs produced according to the method of the test group 3 of Example 1, fresh, no damage, meet the quality standards (GB2749-2015) of duck eggs; 2. Cleaning, disinfection and air drying: use an automatic egg conveyor to transport the duck eggs from the egg basket to the conveyor belt system, sequentially use circulating water and detergent for preliminary cleaning, high-pressure water for rinsing, and pure water for rinsing, and provide a soft-bristle brush roller to assist in removing surface dirt during the cleaning process. The cleaned duck eggs enter the sodium hypochlorite or ozone water spraying disinfection area to effectively kill surface microorganisms, and then use pure water to rinse the residual disinfectant, and then use 0.5% sodium ascorbate solution for 2 minutes of rinsing; 3. Divide the air-dried duck eggs into 6 groups, set up 2 test groups and 4 control groups, and the pickling methods of each group are as follows; Test group A: the dried duck eggs were first soaked in the coating solution for 10 minutes, then the excess solution was drained and the duck eggs were dried, and then the duck eggs were soaked in the 0.5% calcium chloride solution for 10 minutes, and then the duck eggs were taken out and dried; the treated duck eggs were placed in the pickling tank, the pickling solution was injected, the tank was sealed, and the tank was placed in a cool and ventilated place for pickling for 20 days; wherein, the coating solution was prepared by dissolving chitosan and sodium alginate in 2% acetic acid solution to prepare a solution with a chitosan concentration of 1% and a sodium alginate concentration of 1%, and then 0.1% vitamin E acetate was added and mixed to obtain the coating solution; the pickling solution was prepared by mixing 20% NaCl, 0.5% whey protein peptide and 0.1% compound spice, and the rest was water, and the compound spice was star anise, cassia bark and pepper at a ratio of 3:3:2; Test group B: the dried duck eggs were first soaked in the coating solution for 5 minutes, then the excess solution was drained and the duck eggs were dried, and then the duck eggs were soaked in the 0.5% calcium chloride solution for 5 minutes, and then the duck eggs were taken out and dried; the treated duck eggs were placed in the pickling tank, the pickling solution was injected, the tank was sealed, and the tank was placed in a cool and ventilated place for pickling for 20 days; wherein, the coating solution was prepared by dissolving chitosan and sodium alginate in 4% acetic acid solution to prepare a solution with a chitosan concentration of 2% and a sodium alginate concentration of 2%, and then 0.2% vitamin E acetate was added and mixed to obtain the coating solution; the pickling solution was prepared by mixing 25% NaCl, 0.3% whey protein peptide and 0.05% compound spice, and the rest was water, and the compound spice was star anise, cassia bark and pepper at a ratio of 3:3:2; Control group A: the dried duck eggs were not soaked in the coating solution and the calcium chloride solution, and were directly added into the pickling solution for pickling, and the rest was the same as test group A; Control group B: the coating solution did not contain sodium alginate and vitamin E acetate, and the rest was the same as test group A; Control group C: the pickling solution only contained 23% NaCl + 0.08% compound spice, and did not contain whey protein peptide, and the rest was the same as test group A.

[0033] Control group D: the coating solution did not contain vitamin E acetate, and the rest was the same as test group A; 4. Taking out, washing and drying: after the pickling was completed, the duck eggs were taken out, the surface salt frost and impurities were washed with flowing water, and then the duck eggs were further dried in a drying tunnel to remove the surface moisture; 5. Packaging, sealing and sterilization: the pickled duck eggs were vacuum packaged, and then were sent into a horizontal high-pressure steam sterilization pot for sterilization at 121°C and 0.15MPa for 20 minutes, and then were cooled to room temperature to obtain the product.

[0034] The contents of selenium, lutein, DHA, ALA and EPA in the salted duck eggs pickled in test groups A-B and control groups A-D were determined, the determination method was the same as in example 1, the retention rates of selenium, lutein, DHA, ALA and EPA were calculated, the yolk oil outflow rate, salt content and sensory state of the salted duck eggs after pickling were detected, and the results were shown in tables 4 and 5. The salt content is determined according to the method specified in GB5009.44-2016; The detection method of sensory state is to open the salted duck egg sample, place it in a white porcelain plate, and detect it by hand feeling, visual inspection, nose smelling and tasting; The detection method of yolk oil outflow rate is as follows: 3 g of salted egg yolk is added into 35 ml of n-hexane-isopropyl alcohol solution (V / V=3:2), and homogenized at 5000 r / min for 10 min by using a homogenizer. After filtration, the filtrate is transferred to a pre-weighed 50 ml flask. The sample is concentrated by rotary evaporation at 55°C, and then dried in an oven at 105°C to constant weight. The difference between the two weights of the flask is taken as the total fat mass in the yolk. Then, 3 g of salted egg yolk is added into 25 ml of distilled water, and homogenized at 5000 r / min for 10 min by using a homogenizer. The mixture is centrifuged at 3500 r / min for 15 min at room temperature. The supernatant is transferred to a separatory funnel, and 35 ml of n-hexane-isopropyl alcohol solution (V / V=3:2) is added to shake well. After standing for a while, the upper layer in the separatory funnel is transferred to a pre-weighed 50 ml flask. The difference between the two weights of the flask is taken as the free fat mass in the salted duck egg. The oil outflow rate of the salted duck egg is calculated as the free fat content in the salted duck egg divided by the total fat content in the salted egg. Table 4: Duck egg pickling quality

[0035] As can be seen from the above table, the salted duck eggs obtained in test group A and test group B have white and uniform protein, certain elasticity, complete yolk shape, uniform and sandy texture, uniform oil outflow without hard block or crack, rich aroma without odor, high yolk oil outflow rate, and moderate salt content. In combination of test group A and control group A, the yolk oil outflow rate of the salted duck eggs directly pickled in control group A is reduced, and the salt content is increased. In combination of test group A and control group B, the yolk oil outflow rate of the salted duck eggs in control group B without adding sodium alginate and vitamin E acetate in the coating solution is reduced, and the salt content is increased. In combination of test group A and control group C, the yolk oil outflow rate of the salted duck eggs in control group C without whey protein peptide in the pickling solution is reduced. In combination of test group A and control group D, the pickling effect of the salted duck eggs in control group D without adding vitamin E acetate in the coating solution is similar to that of test group A as a whole.

[0036] Table 5: Comparison of core nutrient retention rate

[0037] As can be seen from the above table, the selenium, lutein, DHA, EPA and ALA retention rates of the test group A and the test group B are overall better than those of the control groups A, B, C and D; in combination with the test group A and the control group A, the control group A is directly pickled with the pickling liquid, and the selenium, lutein, DHA, EPA and ALA retention rates are all reduced; in combination with the test group A and the control group B, the control group B does not add sodium alginate and vitamin E acetate to the coating liquid, and the lutein, DHA, EPA and ALA are lost more; in combination with the test group A and the control group C, the control group C does not contain whey protein peptide in the pickling liquid, and the selenium, lutein, DHA, EPA and ALA retention rates are all reduced; in combination with the test group A and the control group D, the control group D does not add vitamin E acetate to the coating liquid, and the retention rates of various nutrients are all reduced, and the lutein, DHA, EPA and ALA retention rates are higher than those of the control group B.

[0038] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the specific embodiments of the present application can be modified or some technical features can be replaced by equivalent ones, which should be covered in the technical solution range claimed by the present application.

Claims

1. A method for producing nutritionally fortified healthy duck eggs, characterized by, The method comprises the following steps: S1, selecting a south-facing water, high dry sunny, good drainage of mountainous gentle slope, and establishing a semi-open duck house; S2, selecting healthy, weight up to standard 120-150 day-old laying Shaoxing ducks; S3, adding 1.5-2.5% of the nutritional fortification feed additive and 0.1-0.2% of the probiotics in the basic feed for feeding, and feeding in a fixed time and quantity, and ensuring sufficient clean drinking water throughout the process, and collecting the duck eggs produced after 21 days of continuous feeding of the nutritional fortification feed additive as the nutritional fortification duck eggs; Probiotic bacteria are Bacillus subtilis and Bifidobacterium animalis lactis in a weight ratio of 2:1 Bacillus subtilis DE111 Bifidobacterium animalis subsp. Lactis BB-12 ;​ The preparation method of the nutritional fortification feed additive comprises the following steps: (1) cold-pressing flaxseed to obtain flaxseed oil and flaxseed meal, and cold-pressing schizochytrium to obtain schizochytrium oil and schizochytrium meal; (2) stirring and dissolving 25-28 parts of flaxseed oil, 12-15 parts of schizochytrium oil and 4-6 parts of lutein ester at 55-65 DEG C to obtain an oil phase; adding 33-37 parts of selenium-rich yeast powder, 13-15 parts of malt dextrin and 2-4 parts of HPMC into 280-320 parts of water, and homogenizing to obtain an aqueous phase; (3) slowly adding the oil phase into the aqueous phase, homogenizing to form a stable emulsion, and performing spray drying to obtain microcapsules; (4) adding 7-9 parts of Eudragit L30D-55, 4-6 parts of betaine hydrochloride, 1.5-2.5 parts of vitamin E and 0.5-1.5 parts of HPMC into water to prepare a coating liquid with a solid content of 25-30%; (5) placing the microcapsules in a fluidized bed for coating to obtain composite nutritional microcapsules; (6) mixing 70-80 parts of flaxseed meal and 20-30 parts of schizochytrium meal to obtain dry materials, and adding fermentation bacteria to ferment the dry materials to obtain a carrier; (7) mixing the composite nutritional microcapsules with the carrier to obtain the nutritional fortification feed additive.

2. The method of producing nutritionally fortified healthy duck eggs as claimed in claim 1, wherein, In the preparation method of the nutritional fortification feed additive, the homogenization treatment in steps (2) and (3) is carried out at 10000-15000 rpm for 5-10 min.

3. The method of producing nutritionally fortified healthy duck eggs as claimed in claim 1, wherein, In the preparation method of the nutritional fortification feed additive, the spray drying in step (3) is carried out at an inlet air temperature of 150-160 DEG C and an outlet air temperature of 60-70 DEG C.

4. The method for producing nutritionally fortified healthy duck eggs as claimed in claim 1 wherein, In the preparation method of the nutritional fortification feed additive, the coating method in step (5) is as follows: the microcapsules are preheated to 38-40 DEG C, sprayed into the coating liquid at a spraying rate of 6-8 ml / min, the inlet air temperature is 65-70 DEG C, the atomization pressure is 1.2-1.5 bar, and the coating weight gain is 8-15% to prepare the composite nutritional microcapsules.

5. The method for producing nutritionally fortified healthy duck eggs as claimed in claim 1 wherein, In the preparation method of the nutritional fortification feed additive, the fermentation method in step (6) is as follows: the flaxseed meal and the schizochytrium meal are mixed to obtain dry materials, 1-2% of fermentation bacteria based on the weight of the dry materials is added, water is added to adjust the moisture content of the dry materials to 40-45%, and the dry materials are fermented at a temperature of 33-36 DEG C and a humidity of 80-85% for 24-48 hours; the fermentation products are dried to a moisture content of less than 5%, crushed and sieved through a 80-mesh sieve to obtain the carrier.

6. The method for producing the nutrient-enriched healthy duck egg according to claim 1 or 5, characterized in that, In the preparation method of the nutrition-enhanced feed additive, the fermentation bacteria used in the fermentation method in step (6) are Lactobacillus plantarum Lactobacillus plantarum EM-12 and Pediococcus acidilactici Pediococcus acidilactici HEW-AP27 mixed at a ratio of 3:

1.

7. A nutritionally fortified health duck egg, characterized in that, produced according to the method of any one of claims 1-6.

8. A method of pickling a nutritionally fortified healthy duck egg, characterized by, comprising the steps of: (1) raw material receiving and pretreatment: collecting fresh, unbroken, and quality standard- conforming duck eggs, which are the nutritionally fortified healthy duck eggs of claim 7, and washing, disinfecting, and air-drying the duck eggs; (2) pickling: immersing the dried duck eggs in a coating liquid for 5-10 minutes, draining the excess solution after taking out, and air-drying; immersing the duck eggs in a 0.5% calcium chloride solution for 5-10 minutes after taking out, draining the excess solution after taking out, and air-drying; placing the treated duck eggs in a pickling jar, injecting a pickling liquid, sealing the container, and placing the container in a cool and ventilated place for pickling for 15-30 days; wherein the coating liquid is prepared by dissolving chitosan and sodium alginate in a 2-4% acetic acid solution to obtain a solution with a chitosan concentration of 1-2% and a sodium alginate concentration of 1-2%, and then adding 0.1-0.2% vitamin E acetate and mixing; (3) taking out of the jar, washing, and drying: taking out the duck eggs after pickling, washing the surface salt frost and impurities with flowing clean water, and then entering a drying tunnel to remove the surface moisture of the duck eggs; (4) packaging, sealing, and sterilization: vacuum packaging the pickled duck eggs, and then placing the duck eggs in a horizontal high-pressure steam sterilization pot for sterilization at 121°C and 0.15 MPa for 15-20 minutes, and then cooling to room temperature to obtain the product.

9. The pickling method of the nutrient-enriched healthy duck egg according to claim 8, characterized in that, In step (2), the pickling liquid has the following formula: 20-25% NaCl, 0.3-0.5% whey protein peptide, 0.05-0.1% compound spice, and the balance being water.

10. The pickling method of the nutritionally fortified healthy duck egg according to claim 8, characterized in that, In step (1), the washing and disinfection method is as follows: using an automatic egg conveying machine to convey the duck eggs from an egg basket to a conveyor belt system, and then sequentially using circulating water and a detergent for preliminary washing, high-pressure clean water for rinsing, and pure water for rinsing; during the washing process, a soft-bristle brush roller is provided to assist in removing surface dirt; after washing, the duck eggs are sprayed with sodium hypochlorite or ozone water in a disinfection zone to effectively kill surface microorganisms; after rinsing the residual disinfectant with pure water, the duck eggs are rinsed with a 0.5%-1% sodium ascorbate solution for 1-2 minutes; The air-drying method is as follows: after washing and disinfecting, the duck eggs are placed in a hot air drying channel to remove the surface moisture, and the drying time is controlled to be 2-5 minutes.

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