A method for preparing a fishy - free and highly - dispersible egg white powder

Abstract

The present invention discloses a method for preparing a non-fishy and highly dispersible egg white powder, belonging to the technical field of food processing. Starting from the optimization of egg white components, the present invention combines antioxidant factor intervention, component optimization (removing reducing sugars, adsorbing with ion exchange resin and removing protein components unfavorable to flavor by microwave-induced pre-denaturation), drying condition control, and subsequent ozone deodorization in multiple processing steps to combinatorially regulate the flavor of the egg white powder, ultimately achieving the preparation of non-fishy egg white powder and ensuring that flavor deterioration does not occur during storage, freight and other flow links. The present invention solves two major problems that need to be urgently solved for egg white powder as a high-quality nutritional raw material, one is the removal of fishy smell from egg white powder, and the other is the improvement of the dispersibility of egg white powder. The concentration and granulation steps have a significant effect on improving the dispersibility of egg white powder, and are of great significance for promoting the high-value utilization of egg white powder and exploring high-quality healthy protein raw materials.

Description

Technical Field

[0001] The present invention relates to a method for preparing odorless and highly dispersible egg white powder, belonging to the technical field of food processing. Background Art

[0002] Egg white is rich in high-quality protein and 8 amino acids essential for human life activities, and its protein utilization rate can reach 99.6%. Spray drying is an important process commonly used in industry to extend the shelf life of egg white and improve its processing performance. However, this process is an oxygen-rich and high-temperature environment, which is extremely easy to induce a series of reactions such as protein denaturation and Strecker degradation, generating and releasing volatile components with special flavors, resulting in an unpleasant fishy smell in the egg white powder, restricting its use in the processing of high-quality, healthy and nutritious foods.

[0003] Conventional egg white deodorization methods include ozone deodorization, yeast fermentation deodorization, activated carbon deodorization, etc. These deodorization methods have problems such as difficulty in industrialization, industrialization, and high costs. Some researchers also use antioxidants to deodorize eggs. Their deodorization mainly occurs in the yolk, and the principle of deodorization is to scavenge free radicals and inhibit lipid oxidation.

[0004] The adsorption equilibrium of proteins to flavor components and the Strecker degradation to produce aldehydes and pyrazine compounds are important ways to form food flavors. The inventor previously used antioxidant factor intervention experiments to compare and verify that protein oxidation during the spray drying process is the key factor causing the generation of fishy smell substances in egg white powder. According to the principle of protein oxidation, it can be inferred that protein free amino acids and α-dicarbonyl compounds are necessary factors for the Strecker degradation reaction, and α-dicarbonyl compounds in food systems mainly come from the Amadori rearrangement and degradation during the Maillard reaction process. Therefore, during the egg white spray drying process, complex biochemical reactions such as protein fragmentation, Maillard reaction, and amorphous aggregation may occur simultaneously. Based on the previous research results, the applicant preliminarily judges that after the oxidation of egg white protein, small molecule carbonyl compounds such as acetic acid, benzaldehyde, and benzoic acid may be "degraded and generated", and long-chain alkanes / aldehydes such as octanal, nonanal, and heptane may be "desorbed and released", constituting the special fishy smell of the egg white powder.

[0005] Therefore, inhibiting protein oxidation and controlling Maillard reaction intermediates during the spray drying process are important focuses for regulating the fishy smell problem of egg white powder. Glucose in egg white is the main substance of the Maillard reaction, which is easy to chelate ferritin and has a strong catalytic effect on protein oxidation. Proteins rich in basic amino acids may be related to the formation of volatile carbonyl compounds. Summary of the Invention

[0006] [Technical Problem]

[0007] The conventional methods for removing fishy smell from egg white have problems such as insignificant effect, high cost, and difficulty in industrial scale-up.

[0008] [Technical Solution]

[0009] To solve the above problems, the present invention starts from optimizing the egg white components, and combines multiple processing steps such as antioxidant factor intervention, component optimization (removing reducing sugars, using ion exchange resin adsorption and microwave-induced pre-denaturation to remove protein components unfavorable to flavor), drying condition control, and post-treatment ozone deodorization to combinatorially regulate the flavor of egg white powder, and finally realizes the preparation of fishy smell-free egg white powder and ensures that flavor deterioration does not occur during storage, freight and other flow links.

[0010] The first object of the present invention is to provide a method for preparing fishy smell-free and highly dispersible egg white powder by controlling the Maillard reaction, which includes the following steps:

[0011] (1) Adsorbing basic proteins:

[0012] Using the method of cation exchange resin adsorption to remove easily deteriorated basic proteins such as lysozyme in egg white to obtain egg white liquid;

[0013] (2) Microwave-induced pre-denaturation:

[0014] Treat the egg white liquid in step (1) at 400 - 800 W for 1 - 2 min to induce the aggregation and sedimentation of heat-unstable proteins, and after filtration, collect the supernatant;

[0015] (3) Removing reducing sugars:

[0016] Using glucose oxidase to perform sugar removal treatment on the supernatant in step (2) to obtain egg white liquid;

[0017] (4) Adding antioxidants:

[0018] Add antioxidants to the egg white liquid in step (3) and mix evenly to obtain an egg white liquid containing antioxidants; wherein, the antioxidant is a mixture of Vc, tea polyphenols, and glutathione; the addition amount of the antioxidant is 0.1 - 1% of the mass of the egg white liquid in step (3);

[0019] (5) Concentration:

[0020] Concentrate the egg white liquid containing antioxidants in step (4) by 1 - 1.5 times to obtain the concentrated egg white liquid;

[0021] (6) Spray drying:

[0022] Perform spray drying on the concentrated egg white liquid obtained in step (5) to obtain egg white powder;

[0023] (7) Granulation:

[0024] Granulate the egg white powder obtained in step (6), and at the same time spray the surfactant aqueous solution to obtain egg white particles;

[0025] (8) Ozone heat drying:

[0026] Perform ozone heat drying on the egg white particles obtained in step (7), and then cool to obtain odorless and highly dispersible egg white powder.

[0027] In one embodiment of the present invention, the adsorption of basic proteins in step (1) is specifically as follows: Wash fresh eggs, break their shells, separate the egg whites and yolks, and collect the egg whites; Adjust the pH of the egg white solution to 6.0 - 8.0 with acid, then mix it with ion exchange resin at a mass ratio of 1:4 - 6, and fully adsorb and separate the basic proteins under stirring. Remove the resin by filtration through a sieve, and collect the egg white solution.

[0028] In one embodiment of the present invention, the characteristics of the microwave heating treatment in step (2) are fast heating rate, easy induction of denaturation of thermally unstable proteins, and partial unfolding of the ovalbumin structure, resulting in a decrease in the ability to bind flavor; Filtration is carried out by plate and frame filtration after cooling at 4°C to remove flocculants such as ovotransferrin.

[0029] In one embodiment of the present invention, the enzyme activity of glucose oxidase in step (3) is 4000 U / g, purchased from DSM; The addition amount of glucose oxidase is 0.03 - 0.5% of the mass of the supernatant in step (2), the hydrolysis time for de - sugaring is 1 - 3 h, and the temperature is 40 - 50°C.

[0030] In one embodiment of the present invention, the mass ratio of Vc, tea polyphenols, and glutathione in the antioxidant in step (4) is 1:0.5 - 1:0.5 - 2.

[0031] In one embodiment of the present invention, the concentration in step (5) is carried out by membrane filtration, and the concentration is up to a protein content of 18 - 24%.

[0032] In one embodiment of the present invention, the concentration in step (5) is to improve the efficiency of the subsequent spray drying, increase the particle size of the powder, reduce the contact with oxygen, control the flavor deterioration caused by protein oxidation, and improve the dispersibility of the egg white powder.

[0033] In one embodiment of the present invention, the inlet air temperature in the spray drying in step (6) is set to 165 - 185°C, and the outlet air temperature is set to 70 - 85°C.

[0034] In one embodiment of the present invention, the surfactant aqueous solution in step (7) includes all amphiphilic surfactants such as phospholipids (soybean phospholipids, egg yolk phospholipids, etc.), rhamnolipids, and monoglycerides; the mass concentration of the surfactant aqueous solution is 0.1-0.6%.

[0035] In one embodiment of the present invention, step (7) is crucial for improving the dispersibility of egg white powder.

[0036] In one embodiment of the present invention, the time of ozone heat drying in step (8) is 3-4 days; ozone heat drying is not limited to using an ozone sterilization hot air circulation oven.

[0037] The second object of the present invention is the non-fishy and highly dispersible egg white powder prepared by the method of the present invention.

[0038] The third object of the present invention is the application of the non-fishy and highly dispersible egg white powder of the present invention in nutritional and health foods such as muscle-building foods and protein supplement foods.

[0039] [Beneficial effects]

[0040] (1) The present invention solves two major problems that need to be urgently solved for egg white powder as a high-quality nutritional raw material, one is the deodorization of egg white powder, and the other is the improvement of the dispersibility of egg white powder. The concentration and granulation steps have a significant effect on improving the dispersibility of egg white powder, and are of great significance for promoting the high-value utilization of egg white powder and exploring high-quality healthy protein raw materials.

[0041] (2) Before spray drying, the present invention concentrates the egg white liquid to a protein content of 18-24%. The benefits are that, on the one hand, it increases the atomized droplet size, reduces the air contact area, and reduces oxidation in the drying process; on the other hand, it obtains powders with larger particle sizes, increases the sedimentation rate to improve the yield, and enhances the redissolution and dispersibility of the powders.

[0042] (3) Starting from the optimization of egg white components, the present invention combines multiple processing steps such as antioxidant factor intervention, drying condition control, and post-treatment ozone deodorization to combinatorially regulate the flavor of egg white powder, and finally realizes the preparation of non-fishy egg white powder, and ensures that flavor deterioration will not occur during storage, transportation and other flowing links. Specific embodiments

[0043] The following describes the preferred embodiments of the present invention. It should be understood that the embodiments are for better explaining the present invention and are not used to limit the present invention.

[0044] Testing method:

[0045] 1. Sensory evaluation of the fishy smell of egg white powder:

[0046] Recruit 15 sensory evaluation personnel to score the fishy smell index of egg white powder. The scoring is based on a ten-point system. Finally, remove the highest and lowest scores, and take the average score as the final score of the sample.

[0047] The scoring criteria refer to Table 1 below:

[0048] Table 1

[0049]

[0050] Compare the fishy smell levels of the samples based on the flavor scores. The lighter the fishy smell, the higher the score.

[0051] 2. Dispersibility test of egg white powder:

[0052] Put 0.5 g of egg white powder into a beaker containing 10 mL of deionized water respectively. After stirring at 700 r / min for 30 s, immediately filter the solution with a 200-mesh sieve;

[0053] After appropriately diluting the filtrate and the solution, take 1 mL of the sample and react with 4 mL of biuret reagent for 30 min, then measure the absorbance value at 540 nm, and calculate the corresponding protein concentration according to the standard curve.

[0054] D30 is expressed by the following formula:

[0055] D30(%) = A1 / A0 × 100

[0056] Wherein, A1 represents the protein content in the sample filtrate after stirring for 30 s, and A0 is the protein content in the rehydrated solution of the unfiltered egg white powder.

[0057] 3. Detection method of volatile compounds (GC-MS):

[0058] Put 4.5 g of egg white solution into a 15-mL headspace vial for the detection of volatile compounds;

[0059] Among them, the GC conditions: use a TR-FFAP (30.0 m × 0.25 mm × 0.25 μm) chromatographic column; injection port: column oven temperature 50.0 °C, injection port temperature 250 °C; injection mode: splitless; flow control mode: linear velocity; pressure 33.4 kPa, carrier gas (He), flow rate 0.8 mL / min; temperature programming: start from 40 °C, increase the temperature to 140 °C at a rate of 5 °C / min, hold for 3 min, then increase the temperature to 230 °C at a rate of 10 °C / min, and hold for 6 min;

[0060] MS conditions: Electron impact source (EI), EI electron energy 70 eV, emission current 1 mA, ion source temperature 210 °C, transfer line temperature 250 °C, no solvent delay, mass scan range 33 - 450 m / z.

[0061] Raw materials used in the examples:

[0062] Glucose oxidase: Enzyme activity is 4000 U / g, purchased from DSM;

[0063] The phospholipid is specifically soybean phospholipid;

[0064] The ion exchange resin is a cation exchange resin.

[0065] In the examples, the solutions mentioned without specifically indicating the solvent are water-based solvents, and the % mentioned without specifically indicating the meaning is the mass percentage.

[0066] Example 1

[0067] A method for preparing odorless and highly dispersible egg white powder by controlling the Maillard reaction, comprising the following steps:

[0068] (1) Adsorbing basic proteins:

[0069] Take fresh eggs, wash them, break their shells, separate the egg whites and yolks, and collect the egg whites; adjust the pH of the egg white solution to 6.5 with acid, then mix it with the ion exchange resin at a mass ratio of 1:5, and fully adsorb and separate basic proteins such as lysozyme under stirring, and use a sieve to filter out the resin to collect the egg white solution;

[0070] (2) Microwave-induced pre-denaturation:

[0071] Adopt the method of microwave-induced flocculation and sedimentation of labile proteins to remove oxidation-catalytic proteins represented by ovotransferrin. Specifically, the egg white solution in step (1) is treated at 400 W for 1 minute, cooled at 4 °C, and then filtered through a plate and frame to collect the supernatant;

[0072] (3) Removing reducing sugars:

[0073] Use glucose oxidase to perform de-sugaring treatment on the supernatant in step (2) to obtain an egg white solution; among them, the addition amount of glucose oxidase is 0.1%, the hydrolysis time is 1.5 h; the temperature is 45 °C;

[0074] (4) Adding antioxidants:

[0075] Add antioxidants to the egg white solution in step (3), mix evenly to obtain an egg white solution containing antioxidants; wherein, the antioxidants are a mixture of Vc, tea polyphenols, and glutathione; the addition amount of the antioxidants is 0.3% of the mass of the egg white solution in step (3); the mass ratio of Vc, tea polyphenols, and glutathione is 1:1:1;

[0076] (5) Concentration:

[0077] By means of membrane filtration, concentrate the egg white solution containing antioxidants in step (4) by 1 time, and the protein content reaches 20% to obtain the concentrated egg white solution;

[0078] (6) Spray drying:

[0079] Perform spray drying on the concentrated egg white solution obtained in step (5), set the inlet air temperature to 175°C and the outlet air temperature to 75°C to obtain egg white powder;

[0080] (7) Granulation:

[0081] Use a fluidized bed granulator to granulate the egg white powder obtained in step (6), and spray a phospholipid aqueous solution with a mass fraction of 0.2% during the granulation process to obtain egg white particles;

[0082] (8) Ozone heat drying:

[0083] Pack the egg white particles obtained in step (7) into trays, place them in an ozone sterilization hot air circulation oven for heat drying treatment for 3 days, and after cooling, perform sub-packaging and packaging to obtain odorless and highly dispersible egg white powder.

[0084] Optimization of the thermal induction conditions in Example 2

[0085] Adjust the microwave treatment conditions in step (2) of Example 1 to 600W and 800W for 2 minutes, and keep the others the same as in Example 1 to obtain odorless and highly dispersible egg white powder.

[0086] Perform performance testing on the obtained odorless and highly dispersible egg white powder, and the test results are as follows:

[0087] The odor score of the egg white powder prepared under the treatment condition of 600W is 9.4;

[0088] The odor score of the egg white powder prepared under the treatment condition of 800W is 9.6, but due to the excessive intensity of microwave heat treatment, partial protein aggregation occurs, and the dispersibility of the obtained egg white powder is slightly poor.

[0089] Optimization of the antioxidant ratio in Example 3

[0090] Adjust the mass ratio of Vc, tea polyphenols, and glutathione in the antioxidant in step (4) of Example 1 to 1:0.5:0.5 and 1:1:2, and keep the others the same as in Example 1 to obtain a fishy-free and highly dispersible egg white powder.

[0091] Perform performance tests on the obtained fishy-free and highly dispersible egg white powder, and the test results are as follows:

[0092] The fishy smell score of the egg white powder prepared with a mass ratio of 1:0.5:0.5 is 9.2;

[0093] The fishy smell score of the egg white powder prepared with a mass ratio of 1:1:2 is 9.2.

[0094] Optimization of the concentration multiple in Example 4

[0095] Adjust the concentration multiple in step (5) of Example 1 to 1.5 times, and keep the others the same as in Example 1 to obtain a fishy-free and highly dispersible egg white powder.

[0096] Perform performance tests on the obtained fishy-free and highly dispersible egg white powder, and the test results are as follows:

[0097] The dispersibility of the egg white powder is 92.1%, indicating that increasing the concentration multiple is conducive to obtaining a powder with larger particles and is beneficial to dissolution and dispersion.

[0098] Comparative Example 1

[0099] Omit steps (1), (2), and (3) in Example 1, and keep the others the same as in Example 1 to obtain an egg white powder.

[0100] Comparative Example 2

[0101] Omit step (4) in Example 1, and keep the others the same as in Example 1 to obtain an egg white powder.

[0102] Comparative Example 3

[0103] Omit steps (5) and (7) in Example 1, and keep the others the same as in Example 1 to obtain an egg white powder.

[0104] Comparative Example 4

[0105] Omit step (8) in Example 1, and keep the others the same as in Example 1 to obtain an egg white powder.

[0106] Perform performance tests on the egg white powders obtained in Example 1 and Comparative Examples 1-4, and the test results are shown in Table 2 below:

[0107] Table 2

[0108]

[0109] The volatile compounds in the egg white powder prepared in Example 1 and Comparative Example 1 were identified, and the comparison results are shown in Table 3.

[0110] As can be seen from Table 3: The branched-chain compounds such as 3-methylbutanal, 2-pentylfuran, and 2-ethyl-1-hexanol, as well as the long-chain aldehyde compounds such as nonanal, heptanal, and hexanal in Example 1 were significantly lower than those in Comparative Example 1, indicating that the method of Example 1 has a significant effect on inhibiting the formation of branched-chain aldehyde compounds related to the Maillard reaction and the release of long-chain aldehyde compounds; thereby realizing the flavor regulation of egg white powder and obtaining an egg white powder product without fishy smell.

[0111] Table 3 Comparison of the concentrations (μg / kg) of volatile compounds in the egg white powder prepared in Example 1 and Comparative Example 1

[0112]

[0113] Comparative Example 5

[0114] The antioxidant in step (4) of Example 1 was adjusted to Vc and tea polyphenol with a mass ratio of 1:1, and the others were kept the same as in Example 1 to obtain egg white powder.

[0115] The obtained egg white powder was subjected to performance testing, and the test results are as follows:

[0116] The overall fishy smell was relatively light. However, it was similar to that of Example 1 in terms of the degree of fishy smell, but because the addition amount of tea polyphenol was slightly higher, there was a faint tea flavor in the egg white powder. It shows that the effect of the combination of the two antioxidants is worse than that of the flavor regulation effect of more antioxidant combinations.

[0117] Comparative Example 6

[0118] The antioxidant in step (4) of Example 1 was adjusted to a single antioxidant Vc, and the others were kept the same as in Example 1 to obtain egg white powder.

[0119] The obtained egg white powder was subjected to performance testing, and the test results are as follows:

[0120] The fishy smell score of the egg white powder was 7.9, which was significantly lower than that of the group using combined antioxidants.

[0121] Comparative Example 7

[0122] The antioxidant in step (4) of Example 1 was adjusted to a single antioxidant tea polyphenol, and the others were kept the same as in Example 1 to obtain egg white powder.

[0123] The obtained egg white powder was subjected to performance testing, and the test results are as follows:

[0124] The fishy smell score of the egg white powder was 8.2, which was significantly lower than that of the group using combined antioxidants.

[0125] Comparative Example 8

[0126] Adjust the antioxidant in step (4) of Example 1 to a single antioxidant glutathione, and keep the others the same as in Example 1 to obtain egg white powder.

[0127] Perform performance tests on the obtained egg white powder, and the test results are as follows:

[0128] The fishy smell score of the egg white powder is 7.5, which is significantly lower than that of the group using combined antioxidants.

[0129] Comparative Example 9

[0130] Delete the spraying of 0.2% phospholipid aqueous solution in step (7) of Example 1, and modify it to granulate after mixing the egg white powder obtained in step (6) and the phospholipid aqueous solution with a mass fraction of 0.2% according to a mass ratio of 100:1; keep the others the same as in Example 1 to obtain egg white powder.

[0131] Perform performance tests on the obtained egg white powder, and the test results are as follows:

[0132] The dispersibility of the egg white powder is significantly lower than that of Example 1, and the dispersibility is only 72.1%.

[0133] Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be defined by the claims.

Claims

1. A method for preparing a fishy - free and highly - dispersible egg white powder by controlling the Maillard reaction, characterized in that, It includes the following steps: (1) Adsorbing basic proteins: Using the method of adsorption by cation exchange resin to remove the easily deteriorating basic proteins in egg white, and obtaining egg white solution; (2) Microwave-induced pre-denaturation: Treating the egg white solution in step (1) at 400 - 800 W for 1 - 2 min to induce the aggregation and sedimentation of heat-labile proteins, filtering, and collecting the supernatant; (3) Removing reducing sugars: Using glucose oxidase to perform sugar removal treatment on the supernatant in step (2) to obtain egg white solution; (4) Adding antioxidants: Adding antioxidants to the egg white solution in step (3), mixing evenly to obtain an egg white solution containing antioxidants; wherein, the antioxidant is a mixture of Vc, tea polyphenols, and glutathione; the mass ratio of Vc, tea polyphenols, and glutathione is 1:0.5 - 1:0.5 - 2; the addition amount of the antioxidant is 0.1 - 1% of the mass of the egg white solution in step (3); (5) Concentration: Concentrating the egg white solution containing antioxidants in step (4) by 1 - 1.5 times to obtain the concentrated egg white solution; (6) Spray drying: Performing spray drying on the concentrated egg white solution obtained in step (5) to obtain egg white powder; (7) Granulation: Performing granulation treatment on the egg white powder obtained in step (6), and simultaneously spraying a surfactant aqueous solution to obtain egg white particles; the surfactant includes phospholipids, rhamnolipids, or monoglycerides; the mass concentration of the surfactant aqueous solution is 0.1 - 0.6%; (8) Ozone heat drying: Performing ozone heat drying on the egg white particles obtained in step (7), and cooling to obtain a non-fishy and highly dispersible egg white powder; the time of ozone heat drying is 3 - 4 days.

2. The method according to claim 1, wherein In step (3), the addition amount of glucose oxidase is 0.03 - 0.5% of the mass of the supernatant in step (2), the hydrolysis time of sugar removal is 1 - 3 h, and the temperature is 40 - 50 °C.

3. The method according to claim 1, characterized in that, In the spray drying described in step (6), the inlet air temperature is set to 165 - 185 °C, and the outlet air temperature is set to 70 - 85 °C.

4. The method according to claim 1, wherein In step (5), the concentration is carried out by the method of membrane filtration and concentrated until the protein content reaches 18 - 24%.

5. The method according to claim 1, characterized in that, The specific operation of adsorbing basic proteins in step (1) is: taking fresh eggs, washing them, breaking their shells, separating egg whites and yolks, and collecting egg whites; adjusting the pH of the egg white solution to 6.0 - 8.0 with acid, then mixing it with the ion exchange resin according to the mass ratio of 1:4 - 6, fully adsorbing and separating basic proteins under stirring, and removing the resin by screening to collect the egg white solution.

6. A non-fishy and highly dispersible egg white powder prepared by the method according to any one of claims 1 - 5.

7. Use of the non-fishy and highly dispersible egg white powder according to claim 6 in the preparation of nutritional and health foods.

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