Phosphatide enzymolysis synergistic interface steady-state protection egg yolk powder and preparation method thereof

Abstract

The invention discloses egg yolk powder with phospholipid enzymolysis synergistic interface steady-state protection and a preparation method of the egg yolk powder, and belongs to the technical field of creation of high-quality egg yolk powder. Carrying out phospholipase A2 controllable enzymolysis pretreatment on the egg yolk liquid under the protection of nitrogen; performing micro-emulsification steady-state construction on the compound colloid of the Arabic gum and the beta-cyclodextrin; and carrying out temperature-controlled spray drying on the pretreatment liquid. The key processes are coupled to form a steady-state pretreatment scheme for actively reconstructing a lipid dispersion state from a molecular level, so that the passive defect that oxidation deterioration cannot be fundamentally inhibited due to the fact that a traditional process only depends on later packaging or external addition of an antioxidant is overcome, and the egg yolk powder with low surface free fat coverage rate (SFCR is less than or equal to 3.5%) is produced. After the product is stored for 90 days in an accelerated manner, the peroxide value growth rate (delta POV) is less than or equal to 60.0%, the key smelly aldehyde total concentration (TCKA) is less than or equal to 2.5 mu g / kg, and the emulsifying activity index retention rate is greater than or equal to 85.0%.

Description

Technical Field

[0001] This invention belongs to the technical field of creating high-quality egg yolk powder, specifically relating to an egg yolk powder with phospholipid enzymatic hydrolysis and synergistic interface stabilization protection and its preparation method. Background Technology

[0002] Egg yolk powder is a nutritious food ingredient with excellent functional properties, widely used in infant formula, baked goods, sauces, and nutritional supplements. It is rich in lecithin, unsaturated fatty acids, vitamins, and functional proteins; however, these very components are also the underlying cause of its instability during processing and storage. During storage, especially under unsuitable temperature and humidity conditions, egg yolk powder is highly susceptible to a series of physicochemical changes, leading to a significant decline in its commercial value and edible quality. Its main deterioration problems include: (1) Fat oxidation, mainly manifested as an increase in peroxide value (POV) and thiobarbituric acid value (TBA), producing volatile aldehydes such as hexanal and pentanal, resulting in unpleasant flavors such as rancidity and paint smell, reduced nutritional value, and potential health risks; (2) Decreased functional properties, mainly manifested as a decrease in emulsification activity index (EAI) and emulsification stability index (ESI), and a decrease in protein solubility, resulting in a poorer application effect as an emulsifier and thickener, and a limited range of product applications; (3) Deterioration of physical state, mainly manifested as clumping and poor fluidity; precipitation of free fat on the surface leads to adhesion to the wall, decreased wettability and dispersibility, resulting in a poor product appearance, measurement accuracy and reconstitution performance, and poor user experience.

[0003] Currently, most technologies for improving the storage stability of egg yolk powder focus on post-processing, such as: directly adding synthetic or natural antioxidants (e.g., BHT, vitamin E, tea polyphenols). While these methods have some effect, they have limitations, may introduce exogenous flavors, and do not adequately protect the already formed lipid structure; nitrogen-filled packaging can effectively isolate oxygen, but it cannot solve the problem of free fat oxidation already present inside the powder, and the packaging cost is high, and it becomes ineffective once the packaging is damaged; using a single wall material (e.g., maltodextrin) for spray drying and encapsulation has limited efficiency in encapsulating oils, and the wall material may crack or permeate during storage, resulting in a short-lasting protective effect. None of these technologies address the intrinsic lipoprotein structure of egg yolk powder, thus failing to fundamentally change its easily oxidized characteristics.

[0004] In summary, addressing the key technical bottlenecks of egg yolk powder during storage, such as rancidity due to fat oxidation, decline in flavor quality, and degradation of functional properties, by starting with the pre-processing stage at the source and through molecular-level structural modification and stabilization, is of great significance for enhancing the added value of egg yolk powder products and expanding their application in high-quality foods, with enormous market potential. Summary of the Invention

[0005] This invention addresses key technical problems in egg yolk powder during storage, such as fat oxidation, flavor deterioration, and decline in functional properties. It establishes a multi-index quality monitoring system with surface free fat coverage (SFCR), total concentration of key odorant aldehydes (TCKA), peroxide value growth rate (ΔPOV), and emulsification activity index retention rate (EAI retention rate) as the core indicators. It also creates a core technology for phospholipid decoupling and microcolloid stabilization pretreatment and develops a method for preparing storage-stable egg yolk powder.

[0006] This invention provides a method for preparing egg yolk powder with phospholipase hydrolysis and synergistic interface stabilization protection, comprising: using fresh egg yolk liquid and reconstituted egg yolk liquid as raw materials, and through processes such as standardization of solid content and pH adjustment, controllable enzymatic hydrolysis by phospholipase A2 under nitrogen atmosphere, microemulsion stabilization construction mediated by compound colloid, and temperature-controlled spray drying, to obtain storage-stable egg yolk powder.

[0007] In one embodiment of the present invention, the fresh egg yolk liquid is derived from fresh eggs that have passed quarantine, and the reconstituted egg yolk liquid is prepared by rehydrating dried egg yolk powder that meets food processing requirements.

[0008] In one embodiment of the present invention, the initial total bacterial count of the fresh egg yolk liquid is ≤10. 4 CFU / g, Salmonella and Staphylococcus aureus must not be detected.

[0009] In one embodiment of the present invention, the standardization of solid content is achieved by adjusting the solid content of the egg yolk liquid to 35%~45% through evaporation and concentration or by adding deionized water. The pH adjustment is achieved by adjusting the pH of the egg yolk liquid to 6.5~7.5 using food-grade citric acid solution or sodium citrate solution.

[0010] In one embodiment of the present invention, the controlled enzymatic hydrolysis of phospholipase A2 under a nitrogen atmosphere refers to adding 0.01% to 0.05% of phospholipase A2 (enzyme activity ≥10,000 U / mg) by mass to the adjusted egg yolk liquid under the protection of nitrogen gas with a purity ≥99.5%, stirring and reacting at 40 to 50 °C for 60 to 120 minutes, followed by enzyme inactivation at 85 °C for 5 minutes.

[0011] In one embodiment of the present invention, the phospholipase A2 under nitrogen atmosphere is controllable enzymatically hydrolyzed, and the reaction process requires continuous introduction of nitrogen to isolate the liquid surface of the reaction system from the air.

[0012] In one embodiment of the present invention, the microemulsion steady-state construction mediated by the compound colloid involves cooling the enzymatically hydrolyzed egg yolk liquid to below 40 °C, adding a compound colloid composed of gum arabic and β-cyclodextrin, wherein the amount of the compound colloid added is 1.0% to 3.0% of the mass of the egg yolk liquid, and the mass ratio of gum arabic to β-cyclodextrin is 1:1 to 3:1; and homogenizing at high speed at 10,000 to 20,000 rpm for 5 to 15 minutes under a nitrogen atmosphere, with the system temperature controlled at 25 to 35 °C during the homogenization process.

[0013] In one embodiment of the present invention, the microemulsion steady-state construction mediated by the compound colloid is wherein the inclusion rate of the β-cyclodextrin used is not less than 98%, and the emulsification stability index (ESI) of gum arabic is not less than 85%.

[0014] In one embodiment of the present invention, the temperature-controlled spray drying involves immediately spray drying the pretreated liquid after microemulsion steady-state construction, with the inlet air temperature controlled at 160~180 ℃ and the outlet air temperature controlled at 70~85 ℃.

[0015] This invention provides egg yolk powder prepared by the above-described method, with an initial peroxide value ≤0.8 meq / kg and a surface free fat coverage ≤3.5%. Furthermore, after 90 days of accelerated testing under storage conditions of 37 ± 1 ℃, relative humidity of 75 ± 5%, and avoiding direct sunlight, the peroxide value growth rate of the egg yolk powder is ≤60.0%, the total concentration of key odor-causing aldehydes is ≤2.5 μg / kg, the emulsification activity index retention rate is ≥85.0%, and the complete dispersion time of 10 g of egg yolk powder in 50 mL of water at 25 ℃ is ≤20 seconds.

[0016] This invention provides the application of the egg yolk powder described above in the food industry.

[0017] The technical advantages of this invention are mainly reflected in the following three aspects: First, the core technology for which the patent is applied focuses on the pretreatment stage at the source of egg yolk powder preparation. It has pioneered the "phospholipid hydrolysis coupled microgel stabilization pretreatment" technology, which achieves stabilization through molecular structure modification rather than relying on back-end packaging or additives, demonstrating outstanding originality.

[0018] Second, the patent application is the first to systematically combine the physical structural indicator of surface free fat coverage (SFCR) with the flavor chemical indicator of total concentration of key odorant aldehydes (TCKA), as well as the peroxide value growth rate (ΔPOV) and the emulsification activity index retention rate (EAI retention rate), to construct a multi-dimensional and quantifiable egg yolk powder storage quality monitoring and evaluation system.

[0019] Third, based on the fundamental problem of easy oxidation of egg yolk lipids, this invention patent application has created a new pretreatment process that combines "controllable enzymatic hydrolysis under nitrogen protection" and "steady-state construction of compound colloidal microemulsion". Specifically, by controlling the amount of phospholipase A2 added to 0.01%~0.05% of the mass of egg yolk liquid and the amount of compound colloid (gum arabic and β-cyclodextrin, mass ratio 1:1~3:1) added to 1.0%~3.0%, the resulting egg yolk powder, after 90 days of accelerated storage, has a ΔPOV≤60.0%, TCKA≤2.5 μg / kg, EAI retention rate≥85.0%, and SFCR≤3.5%, providing a fundamental solution for comprehensively improving the storage quality of egg yolk powder.

[0020] The initial peroxide value (POV) was tested to be ≤0.8 meq / kg, and the surface free fat coverage (SFCR) was ≤3.5%. Furthermore, accelerated testing for 90 days under storage conditions of 37 ± 1 ℃, relative humidity of 75 ± 5%, and avoidance of direct sunlight confirmed that the peroxide value growth rate (ΔPOV) of the prepared egg yolk powder was ≤60.0%, significantly lower than that of the control group (i.e., the control group of egg yolk powder samples made from the same raw materials but without phospholipid hydrolysis and microgel stabilization pretreatment, and only directly spray-dried, had a ΔPOV ≥150.0%). P <0.05); the total concentration of key odor-causing aldehydes in the prepared egg yolk powder was ≤2.5 μg / kg in the TCKA product group, and was significantly lower than that in the control group (TCKA control group ≥8.0 μg / kg). P <0.05); the emulsifying activity index (EAI) retention rate of the prepared egg yolk powder was ≥85.0% in the product group, and was significantly higher than that in the control group (EAI retention rate ≤60.0% in the control group). P <0.05 indicates that the three indicators of fat oxidation, formation of undesirable flavor substances, and functional property degradation in egg yolk powder pretreated with phospholipid decoupling microgel stabilization were significantly better than those in the control group. P <0.05). Detailed Implementation

[0021] The testing methods used in this invention: The method for determining surface free fat coverage (SFCR) is as follows: take an egg yolk powder sample, stain it specifically with Sudan III staining solution, and then randomly select no less than 10 fields of view under a 100x optical microscope for image analysis, and calculate the percentage of the surface area of ​​the stained particles to the total surface area.

[0022] The total concentration of critical odor-causing aldehydes (TCKA) refers to the sum of the concentrations of three aldehydes: hexanal, pentanal, and heptanal. It is determined by headspace solid-phase microextraction combined with gas chromatography-mass spectrometry (HS-SPME / GC-MS).

[0023] The time for complete dispersion of 10 g of storage-stable egg yolk powder in 50 mL of 25 °C water after 90 days of accelerated storage.

[0024] The peroxide value was measured as follows: 0.1 g of sample was accurately weighed and vortexed with 3 mL of isooctane. 50 μL of the test solution was added to 1.45 mL of a prepared methanol-n-butanol (2:1) solution, 10 μL of ammonium thiocyanate solution (1 g / mL), and 10 μL of fresh ferrous chloride solution (0.81 g of barium chloride and 1 g of ferrous sulfate dissolved in 0.5 mol / L hydrochloric acid; allowed to stand in the dark, and the supernatant was collected). The mixture was reacted in the dark for 20 minutes, and the absorbance was measured at 510 nm.

[0025] POV = [A 510 [+0.0172) / 0.8094] × 60.

[0026] EAI retention rate: 0.2 g of sample was dissolved in 100 mL of deionized water and magnetically stirred at 500 rpm for 30 min to prepare a stock suspension. 30 mL of the suspension was mixed with 10 mL of refined soybean oil and homogenized at 8000 rpm for 3 min using an FSH2A homogenizer. Then, 5 mL of 0.1% (m / v) SDS solution was added, and homogenization was repeated under the same conditions. After standing and separation, the supernatant was collected, and the absorbance was measured at 500 nm using 0.1% SDS solution as a blank. Absorbance was measured immediately after homogenization and again after standing for 10 min.

[0027]

[0028] The absorbance at time 0 is denoted by A0, while the absorbance of the emulsion at 10 minutes is denoted by A... 10 The expression value of 0.25 indicates the volume fraction of oil in the solution matrix. The symbol C represents the mass concentration value, originally recorded as an exact 0.01 g / mL. N is used to indicate the dilution factor for the application of the solution in question.

[0029] EAI retention rate (%) = (EAI value of the sample after storage / initial EAI value of the sample before storage) × 100%.

[0030] Phospholipase A1 (Aspergillus oryzae), brand: Aladdin; Phospholipase A2 (PLA2) is derived from porcine pancreas, brand: Macklin, with enzyme activity ≥10,000 U / mg.

[0031] Comparative Example 1 Fresh egg yolk liquid was taken and its solid content was adjusted to 40% and pH to 7.0. Subsequently, without any stabilization pretreatment such as phospholipid hydrolysis and compound colloidal microemulsion, it was directly spray-dried with the inlet air temperature controlled at 170 ℃ and the outlet air temperature controlled at 75 ℃. The resulting sample was the "control group sample".

[0032] Furthermore, after 90 days of accelerated testing under storage conditions of 37 ± 1 ℃, relative humidity of 75 ± 5%, and avoiding direct sunlight, the following results were confirmed: the peroxide value growth rate ΔPOV was 150.2%, the total concentration of key odorant aldehydes TCKA was 9.8 μg / kg, the emulsification activity index retention rate (EAI retention rate) was 61.5%, and the complete dispersion time of 10 g sample in 50 mL of 25 ℃ water was ≥35 seconds.

[0033] Example 1 A method for preparing storage-stable egg yolk powder using phospholipid enzyme hydrolysis coupled with microgel stabilization pretreatment requires the following steps to be performed under continuous nitrogen gas with a purity ≥99.5%: (1) Solid content and pH adjustment: Take fresh egg yolk liquid and adjust its solid content to 35% and pH to 6.5; (2) Controllable enzymatic hydrolysis of phospholipase A2 under nitrogen atmosphere: Add 0.01% of phospholipase A2 (enzyme activity ≥10,000 U / mg) to the egg yolk liquid in step (1), stir and react at 40 °C for 60 minutes, and then inactivate the enzyme at 85 °C for 5 minutes to obtain enzymatically hydrolyzed egg yolk liquid; (3) Construction of microemulsion steady state mediated by compound colloid: The enzymatically hydrolyzed egg yolk liquid obtained in step (2) was cooled to 35 °C, and a compound colloid composed of gum arabic and β-cyclodextrin was added. The amount of compound colloid added was 1.0% of the mass of egg yolk liquid, and the mass ratio of gum arabic to β-cyclodextrin was 3:1. Under a nitrogen atmosphere, the mixture was sheared and homogenized at a high speed of 20,000 rpm for 15 minutes, and the temperature of the system during the homogenization process was controlled at 35 °C to form a microemulsion steady state pretreatment solution. (4) Temperature-controlled spray drying: The pretreatment liquid obtained in step (3) is immediately spray dried, with the inlet air temperature controlled at 180 ℃ and the outlet air temperature controlled at 80 ℃, to obtain storage-stable egg yolk powder.

[0034] The initial peroxide value (POV) of the prepared egg yolk powder was 0.7 meq / kg, and the surface free fat coverage (SFCR) was 3.2%. Accelerated testing for 90 days under storage conditions of 37 ± 1 ℃, relative humidity of 75 ± 5%, and avoidance of direct sunlight confirmed that the peroxide value growth rate (ΔPOV) of the prepared egg yolk powder was 58.5%, the total concentration of key odorant aldehydes (TCKA) was 2.4 μg / kg, the emulsification activity index retention rate (EAI retention rate) was 86.5%, and the complete dispersion time of 10 g sample in 50 mL of 25 ℃ water was 18 seconds. All of these indicators were significantly better than those of the untreated control group sample. P <0.05).

[0035] Example 2 A method for preparing storage-stable egg yolk powder using phospholipid enzyme hydrolysis coupled with microgel stabilization pretreatment requires the following steps to be performed under continuous nitrogen gas with a purity ≥99.5%: (1) Solid content and pH adjustment: Take the reconstituted egg yolk solution and adjust its solid content to 45% and pH to 7.5; (2) Controllable enzymatic hydrolysis of phospholipase A2 under nitrogen atmosphere: Add 0.05% of the mass of phospholipase A2 (enzyme activity ≥10,000 U / mg) to the egg yolk liquid in step (1), stir and react at 50 °C for 90 minutes, and then inactivate the enzyme at 85 °C for 5 minutes to obtain enzymatically hydrolyzed egg yolk liquid; (3) Construction of microemulsion steady state mediated by compound colloid: The enzymatically hydrolyzed egg yolk liquid obtained in step (2) was cooled to 35 °C, and a compound colloid composed of gum arabic and β-cyclodextrin was added. The amount of compound colloid added was 3.0% of the mass of egg yolk liquid, and the mass ratio of gum arabic to β-cyclodextrin was 1:1. Under a nitrogen atmosphere, the mixture was sheared and homogenized at a high speed of 10,000 rpm for 5 minutes, and the temperature of the system during the homogenization process was controlled at 25 °C to form a microemulsion steady state pretreatment solution. (4) Temperature-controlled spray drying: The pretreatment liquid obtained in step (3) is immediately spray dried, with the inlet air temperature controlled at 160 ℃ and the outlet air temperature controlled at 70 ℃, to obtain storage-stable egg yolk powder.

[0036] The initial peroxide value (POV) of the prepared egg yolk powder was 0.6 meq / kg, and the surface free fat coverage (SFCR) was 3.0%. Accelerated testing for 90 days under storage conditions of 37 ± 1 ℃, relative humidity of 75 ± 5%, and avoidance of direct sunlight confirmed that the peroxide value growth rate (ΔPOV) of the prepared egg yolk powder was 56.2%, the total concentration of key odorant aldehydes (TCKA) was 2.1 μg / kg, the emulsification activity index (EAI) retention rate was 87.8%, and the complete dispersion time of 10 g sample in 50 mL of 25 ℃ water was 16 seconds. All of these indicators were significantly better than those of the untreated control group sample. P <0.05).

[0037] Example 3 A method for preparing storage-stable egg yolk powder using phospholipid enzyme hydrolysis coupled with microgel stabilization pretreatment requires the following steps to be performed under continuous nitrogen gas with a purity ≥99.5%: (1) Solid content and pH adjustment: Take fresh egg yolk liquid and adjust its solid content to 40% and pH to 7.0; (2) Controllable enzymatic hydrolysis of phospholipase A2 under nitrogen atmosphere: Add 0.03% of the mass of phospholipase A2 (enzyme activity ≥10,000 U / mg) to the egg yolk liquid in step (1), stir and react at 45 °C for 90 minutes, and then inactivate the enzyme at 85 °C for 5 minutes to obtain enzymatically hydrolyzed egg yolk liquid; (3) Construction of microemulsion steady state mediated by compound colloid: The enzymatically hydrolyzed egg yolk liquid obtained in step (2) was cooled to 35 °C, and a compound colloid composed of gum arabic and β-cyclodextrin was added. The amount of compound colloid added was 2.0% of the mass of egg yolk liquid, and the mass ratio of gum arabic to β-cyclodextrin was 2:1. Under a nitrogen atmosphere, the mixture was sheared and homogenized at a high speed of 15,000 rpm for 10 minutes, and the temperature of the system during the homogenization process was controlled at 30 °C to form a microemulsion steady state pretreatment solution. (4) Temperature-controlled spray drying: The pretreatment liquid obtained in step (3) is immediately spray dried, with the inlet air temperature controlled at 170 ℃ and the outlet air temperature controlled at 75 ℃, to obtain storage-stable egg yolk powder.

[0038] The initial peroxide value (POV) of the prepared egg yolk powder was 0.5 meq / kg, and the surface free fat coverage (SFCR) was 2.5%. Accelerated testing for 90 days under storage conditions of 37 ± 1 ℃, relative humidity of 75 ± 5%, and avoidance of direct sunlight confirmed that the peroxide value growth rate (ΔPOV) of the prepared egg yolk powder was 49.8%, the total concentration of key odorant aldehydes (TCKA) was 1.5 μg / kg, the emulsification activity index retention rate (EAI retention rate) was 91.2%, and the complete dispersion time of 10 g sample in 50 mL of 25 ℃ water was 12 seconds. All of these indicators were significantly better than those of Examples 1 and 2, and the untreated control group sample. P <0.05).

[0039] Table 1 shows a comparison of the effects of existing processing technologies with those of the present invention.

[0040] Table 1. Comparison of the effects of different egg yolk powder storage stability treatment techniques

[0041] Comparative Example 2 A method for preparing egg yolk powder, the preparation steps are exactly the same as those in Example 3, the only difference is that the addition of phospholipase A2 and the enzymatic hydrolysis reaction in step (2) are omitted, that is, step (3) is carried out directly after adjusting the pH.

[0042] The initial SFCR of the prepared egg yolk powder was 8.5%. After 90 days of accelerated storage, its ΔPOV was confirmed to be 125.3%, TCKA to be 9.8 μg / kg, and EAI retention rate to be 62.1%. All indicators were significantly worse than those in Example 3. P The value was <0.05, indicating that the lack of enzymatic pretreatment could not effectively reconstruct the lipid structure, resulting in a significant decrease in oxidative stability and functional retention.

[0043] Comparative Example 3 A method for preparing egg yolk powder, the preparation steps of which are exactly the same as those in Example 3, the only difference being that: nitrogen protection is not used in the entire preparation process, and it is carried out in air.

[0044] The initial POV of the prepared egg yolk powder was 1.5 meq / kg, and the SFCR was 4.8%. After 90 days of accelerated storage, its ΔPOV was confirmed to be 102.7%, TCKA was 6.5 μg / kg, and EAI retention rate was 71.5%. All indicators were significantly worse than those of Example 3. P <0.05), indicating a lack of inert gas protection, significant oxidation occurs during processing, severely compromising the product's storage stability.

[0045] Comparative Example 4 A method for preparing egg yolk powder, the preparation steps are exactly the same as those in Example 3, the only difference is that step (3) is omitted, that is, no compound colloid is added to the enzymatic hydrolysate, and no high-speed shear homogenization is performed, and spray drying is performed directly.

[0046] The initial SFCR of the prepared egg yolk powder was as high as 15.2%. After 90 days of accelerated storage, it was confirmed that its ΔPOV was 185.6%, TCKA was 15.3 μg / kg, and EAI retention rate was only 55.8%. All indicators were significantly worse than those of Example 3. P <0.01), indicating the lack of a microemulsion steady-state construction step, which prevents the encapsulation and immobilization of lipids released after enzymatic hydrolysis, making the product highly susceptible to oxidative rancidity and severe loss of function.

[0047] Comparative Example 5 A method for preparing egg yolk powder, the preparation steps are exactly the same as those in Example 3, the only difference being that the compound colloid (gum arabic: β-cyclodextrin = 2:1) in step (3) is replaced with maltodextrin.

[0048] The initial SFCR of the prepared egg yolk powder was 7.1%. After 90 days of accelerated storage, its ΔPOV was confirmed to be 95.4%, TCKA to be 5.2 μg / kg, and EAI retention rate to be 75.3%. All indicators were significantly inferior to those of Example 3. P The value is <0.05, demonstrating that the specific gum arabic and β-cyclodextrin complex system has irreplaceable advantages in forming a stable encapsulation structure and synergistic antioxidant effect.

[0049] Comparative Example 6 A method for preparing egg yolk powder, the preparation steps of which are exactly the same as those in Example 3, the only difference being that phospholipase A2 in step (2) is replaced with phospholipase A1 in equal amounts.

[0050] The initial SFCR of the prepared egg yolk powder was 5.0%. After 90 days of accelerated storage, its ΔPOV was confirmed to be 78.3%, TCKA to be 3.8 μg / kg, and EAI retention rate to be 80.1%. All indicators were significantly worse than those in Example 3. P The value of <0.05 indicates that phospholipase A2 is superior to phospholipase A1 in specifically hydrolyzing the Sn-2 site to generate lysophosphatidylcholine with better emulsifying properties, which is the key to achieving the best stabilization effect.

[0051] The embodiments provided above are not intended to limit the scope of the invention, nor are the described steps intended to limit the order of execution. Any obvious modifications made to the invention by those skilled in the art based on existing common knowledge also fall within the scope of protection defined by the claims.

Claims

1. A phospholipid enzymatic hydrolysis-synergistic interface stabilization protection method for egg yolk powder, characterized in that, Using fresh or reconstituted egg yolk liquid as raw material, a storage-stable egg yolk powder was prepared through a process involving standardization of solid content and pH adjustment, controlled enzymatic hydrolysis with phospholipase A2 under a nitrogen atmosphere, construction of microemulsion steady state mediated by compound colloids, and temperature-controlled spray drying. The egg yolk powder had an initial peroxide value ≤0.8 meq / kg and a surface free fat coverage ≤3.5%. Accelerated testing over 90 days confirmed that its peroxide value growth rate was ≤60.0%, the total concentration of key odorant aldehydes was ≤2.5 μg / kg, the emulsification activity index retention rate was ≥85.0%, and the complete dispersion time of 10 g of egg yolk powder in 50 mL of water at 25 ℃ was ≤20 seconds.

2. A method for preparing egg yolk powder with phospholipid enzymatic hydrolysis and synergistic interface stabilization protection, characterized in that, Using fresh or reconstituted egg yolk liquid as raw material, a storage-stable egg yolk powder is prepared through a process involving standardization of solid content and pH adjustment, controlled enzymatic hydrolysis with phospholipase A2 under a nitrogen atmosphere, stable microemulsion construction mediated by a compound colloid, and temperature-controlled spray drying. Specifically, this process includes: 1) The standardization of solid content mentioned above is achieved by adjusting the solid content of egg yolk liquid to 35%~45% through evaporation and concentration or by adding deionized water; 2) The pH adjustment mentioned above is achieved by using food-grade citric acid solution or sodium citrate solution to adjust the pH of the egg yolk liquid to 6.5~7.5; 3) The nitrogen atmosphere mentioned refers to the fact that the enzymatic hydrolysis and homogenization processes are carried out under the protection of nitrogen with a purity of ≥99.5%, so that the liquid surface of the reaction system is isolated from the air. 4) The controlled enzymatic hydrolysis of phospholipase A2 is achieved by adding 0.01% to 0.05% of phospholipase A2 by mass to the regulated egg yolk liquid, wherein the phospholipase A2 enzyme activity is ≥10,000 U / mg, and stirring at 40 to 50°C for 60 to 120 minutes, followed by enzyme inactivation at 85°C for 5 minutes. 5) The microemulsion steady-state construction mediated by the compound colloid is carried out by cooling the enzymatically hydrolyzed egg yolk liquid to below 40°C and adding a compound colloid composed of gum arabic and β-cyclodextrin; the amount of the compound colloid added is 1.0%~3.0% of the mass of the egg yolk liquid, and the mass ratio of gum arabic to β-cyclodextrin is 1:1~3:1; the mixture is homogenized by high-speed shearing at 10,000~20,000 rpm for 5~15 minutes under a nitrogen atmosphere, and the system temperature is controlled at 25~35°C during the homogenization process. 6) The temperature-controlled spray drying method involves immediately spray drying the pretreatment liquid after microemulsion steady-state construction, with the inlet air temperature controlled at 160~180℃ and the outlet air temperature controlled at 70~85℃.

3. The method for preparing egg yolk powder with synergistic interface stabilization protection by phospholipid hydrolysis according to claim 2, characterized in that, The fresh egg yolk liquid is derived from fresh eggs that have passed quarantine inspection, and the reconstituted egg yolk liquid is prepared by rehydrating dried egg yolk powder that meets food processing requirements.

4. The method for preparing egg yolk powder with synergistic interface stabilization protection according to claim 2 or 3, characterized in that, The initial total bacterial count of the fresh egg yolk liquid is ≤10. 4 CFU / g, Salmonella and Staphylococcus aureus must not be detected.

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