A refining process for chicken fat

Abstract

The present application relates to a kind of chicken oil refining process, it is related to animal oil technology field, wherein the refining process includes pretreatment, low-temperature degumming, deacidification and decolorization, low-temperature deodorization, ceramic membrane filtration.The refining process of the present application is through the steps such as biological enzyme directional degumming, charged membrane separation deacidification and decolorization, nitrogen microbubble low-temperature deodorization, realizes the efficient refining of chicken oil at low temperature, so that the nutrient substance of chicken oil is not oxidized.

Description

Technical Field

[0001] This invention relates to the field of animal fat technology, and in particular to a refining process for chicken fat. Background Technology

[0002] Oils and fats have functions such as providing energy, promoting the absorption and utilization of fat-soluble nutrients, and providing essential fatty acids. In addition, some special oils and fats also have pharmacological effects such as gene regulation, promoting wound healing, anti-tumor, antiviral, and antibacterial effects. Some oils and fats can also be used as industrial oils. Therefore, oils and fats have a wide range of applications in the food, medicine and industrial fields.

[0003] Animal fats typically exist within oilseed cells in the form of fat granules or droplets, or they may exist intracellularly by combining with other macromolecules, such as forming lipoproteins with proteins or lipopolysaccharides with carbohydrates. Common methods for extracting animal fats include: boiling, cooking, solvent extraction, enzymatic hydrolysis, supercritical fluid extraction, and water extraction. If handled properly, the extracted animal fats can be used without further processing. However, in practice, due to factors such as blood stains from slaughter, the resulting products often have excessively high acid values ​​or contain impurities such as collagen. Therefore, these animal fats require further refining.

[0004] Chinese invention patent application CN109234006A discloses a refining process for animal fats. The process includes: conveying crude oil into a refining vessel and stirring it at a speed of 55 r / min to 65 r / min while preheating it to 60°C to 65°C; adding hot brine to the refining vessel; reducing the stirring speed to 25 r / min to 35 r / min; stopping stirring when the flocculated particles show obvious separation, allowing it to stand for 2.5 h to 4 h to separate and degumme; adding hot soft water to the refining vessel while stirring, allowing it to settle, separating it to remove residual soap residue, and then transferring the oil to an oil storage tank; and conveying the oil in the storage tank to a dryer for drying. The drying temperature of the dryer is 100℃~110℃; 1%~4% of food-grade activated clay by weight of the oil is added and thoroughly mixed, and the oil is decolorized for 20 minutes at an oil temperature of 110℃~120℃ and a pressure of 6kPa~7kPa; the decolorized oil is pumped into a vibrating filter and then filtered sequentially through the vibrating filter and a bag filter; the filtered oil is pumped into a deodorizing tower using a gas separator oil pump, and pumping is stopped when the oil reaches the specified liquid level in the deodorizing tower. The deodorizing tower circulates for 30 minutes, and when the oil temperature in the deodorizing tower rises to 230℃~250℃, a sample is taken for testing. After passing the test, the oil outlet temperature is set, and the refined animal fat is output.

[0005] This invention's refining process improves the quality of refined animal fats, increases production efficiency, saves energy, and reduces costs. Compared to animal fats like beef tallow and lard, chicken fat contains a large amount of non-hydrated phospholipids (β-phospholipids) (accounting for 40%~50% of the total phospholipids). Hot brine can only remove hydrated phospholipids (α-phospholipids), and the remaining β-phospholipids are oxidized in subsequent high-temperature deodorization (230~250℃), causing phospholipid oxidation and discoloration during deodorization. Chicken fat also contains a large amount of protein and sugar colloidal substances, which cannot be completely removed by conventional filtration. Incomplete degumming leads to poor fat stability and easy rancidity. The free fatty acid content in chicken fat is usually 2%~5%, and soft water washing in the above process cannot remove free fatty acids. Although high-temperature deodorization can volatilize some free fatty acids, the remaining free fatty acids catalyze oxidation, leading to an increase in peroxide value. Chicken fat contains natural antioxidants (such as vitamin E and oryzanol), but bleaching clay selectively adsorbs these components, increasing the loss rate of vitamin E and leading to decreased oxidative stability. Meanwhile, during decolorization at 110-120℃, unsaturated fatty acids (such as oleic acid and linoleic acid) in chicken fat oxidize to form hydroperoxides, which decompose into aldehydes and ketones (off-odor substances) during the subsequent deodorization stage. This is especially true for high-value-added applications where chicken fat quality requirements are high. In conclusion, to obtain high-quality chicken fat, it is necessary to develop a suitable refining process. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a refining process for chicken fat. The refining process of this invention involves steps such as bio-enzymatic directional degumming, charged membrane separation for deacidification and decolorization, and nitrogen microbubble low-temperature deodorization, achieving efficient refining of chicken fat at low temperatures and preventing the oxidation of its nutrients.

[0007] In a first aspect, the present invention provides a refining process for chicken fat, the refining process comprising the following steps:

[0008] Pretreatment: Chicken feather oil is passed through an 80-100 mesh vibrating screen, the oil temperature is raised to 45-50℃, and stirred at 30-50 r / min for 8-12 min;

[0009] Low-temperature degumming: Based on the weight of crude oil, 0.02-0.05% w / w phospholipase A1 and 0.005-0.015% w / w rosemary extract are dissolved in a 0.08-0.12M citrate buffer solution with a pH of 4.0-5.0 to obtain a mixed solvent. The mixed solvent is preheated to 45-50℃, and then added to the pretreated chicken feather oil. The mixture is stirred at a low speed of 30-50 r / min for 25-35 min, and then heated to 80-90℃ and held for 3-8 min to inactivate the enzyme, thus obtaining enzymatically hydrolyzed oil.

[0010] Deacidification and decolorization: Under the conditions of pressure 1-2MPa, temperature 45-50℃, and pH 4.5-5.0, the enzymatically hydrolyzed oil is tangentially circulated through the surface of the sulfonated polyethersulfone nanofiltration membrane at a flow rate of 1.5-2.5m / s, with a single pass time ≤10min, and the permeate oil is collected;

[0011] Low-temperature deodorization: The temperature of the permeated oil is raised to 175-180℃, and nitrogen microbubbles are introduced into the oil under a pressure of 9-11kPa. The reaction is carried out for 10-20 minutes to obtain deodorized oil.

[0012] Ceramic membrane filtration: The deodorized oil is filtered through a 0.2μm Al2O3 ceramic membrane at a pressure of 0.5-1.0MPa and a temperature of 55-65℃ at a tangential flow rate of 1-3m / s to obtain the chicken oil.

[0013] In the above technical solution, vibrating screening, based on the size exclusion effect, intercepts solid impurities (bone debris, connective tissue) and removes large particles. At 50℃, the viscosity of the oil decreases, Brownian motion is enhanced, and the initial aggregated state of the colloid is disrupted, creating a uniform reaction interface for enzymatic hydrolysis and improving degumming efficiency.

[0014] Phospholipase A1 can specifically cleave the Sn-1 ester bond in phospholipid molecules, converting non-hydrated phospholipids (β-phospholipids) into lysophospholipids, greatly enhancing water solubility. Rosemary extract can inhibit oxidation, and its oxalic acid can chelate metal ions (Fe). 2+ / Cu + ), blocking the chain reaction of lipid peroxidation free radicals.

[0015] The sulfonic acid groups (-SO3H) on the surface of the sulfonated polyethersulfone nanofiltration membrane ionize to generate a negative charge, and the free fatty acids dissociate into RCOO at pH 5.0. - They are trapped due to the repulsion of the negative charge of the membrane. The membrane pore size is 0.5 nm, which can physically trap carotenoids and chlorophyll derivatives.

[0016] Nitrogen gas generates bubbles with a diameter of 50-200 μm, creating a gas-liquid interface area of ​​2000 m² / m³. Volatile odor compounds (aldehydes, ketones) diffuse from the oil phase into the bubbles according to Henry's Law. The rate of trans fatty acid formation decreases at 180℃.

[0017] The oil flows tangentially across the membrane surface at a speed of 1-3 m / s for cross-flow sieving. Shear force peels off the filter cake layer, and the 0.2 μm pore size traps colloidal particles and thermal aggregates for deep impurity removal.

[0018] Optionally, the preparation steps of the sulfonated polyethersulfone nanofiltration membrane are as follows: immerse polyethersulfone particles in concentrated sulfuric acid at a liquid-to-solid ratio of 18-22:1, and magnetically stir at 100-300 r / min and 35-45℃ for 80-100 min. Pour the reaction solution into ice water to terminate the reaction, filter to obtain sulfonated polyethersulfone, wash with water until neutral, and dry at 55-65℃. Dissolve the sulfonated polyethersulfone in 18% w / w N,N-dimethylacetamide and stir at 55-65℃ until a transparent viscous liquid is obtained, thus obtaining a casting solution. Cast the casting solution onto a glass plate and immediately immerse it in room temperature deionized water for 25-35 s to solidify. Transfer the membrane to a 35-45℃ water bath for 0.8-1.2 h, and then dry it in an oven at 55-65℃ for 1-3 h.

[0019] In the above technical solution, the SO3 groups in concentrated sulfuric acid attack the benzene ring of polyethersulfone, resulting in electrophilic substitution. N,N-dimethylacetamide disrupts the intermolecular hydrogen bonds of sulfonated polyethersulfone, forming a homogeneous solution. Water is miscible with N,N-dimethylacetamide, triggering non-solvent-induced phase separation, causing sulfonated polyethersulfone to precipitate and form a film. A dense separation layer forms on the surface, while a macroporous support layer forms at the bottom. Residual N,N-dimethylacetamide is extracted using a water bath to prevent membrane pore collapse, and the drying process fixes the porous structure.

[0020] Optionally, the low-temperature degumming step further includes dissolving 0.2-0.5% w / w phospholipase A1, 0.005-0.015% w / w rosemary extract, and 0.01-0.02% w / w phytate-zinc coordination polymer in a citrate buffer solution with a concentration of 0.08-0.12M and a pH of 4.0-5.0, based on the weight of crude oil, to obtain a mixed solvent.

[0021] In the above technical solutions, although sarsaparilla acid in rosemary extract can chelate metal ions, its ability to scavenge free radicals is insufficient. Phytic acid in phytic acid-zinc coordination polymers can chelate Fe... 3+ / Cu 2+ It blocks metal-catalyzed oxidation, including Zn. 2+ It can activate the ortho-dihydroxyl groups of rosmarinic acid, enhance the scavenging rate of ·OH, and synergistically enhance antioxidant activity with rosemary extract.

[0022] Optionally, the preparation steps of the phytic acid-zinc coordination polymer are as follows: Sodium phytate is dissolved in hot water at 55-65℃ to prepare a 0.1M solution A, and zinc acetate is dissolved in water at room temperature to prepare a 0.15M solution B. Solution B is slowly added dropwise to solution A, with a volume ratio of solution A to solution B of 1:1. Under magnetic stirring at 400-600 r / min, a white flocculent precipitate is immediately formed. After standing at 55-65℃ for 8-12 min, it is centrifuged at 3500-4500 rpm for 5-8 min, then washed 2-3 times with water at 55-65℃, and dried at 55-65℃ for 1-3 h to obtain the phytic acid-zinc coordination polymer.

[0023] In the above technical solutions, hot water dissolution can improve the solubility of sodium phytate (it easily gels in cold water), and the use of zinc acetate avoids the introduction of sulfate impurities. 2+ With the phosphate group (-PO4) in phytic acid molecules 3- Coordination crosslinking occurs, forming a three-dimensional network polymer. Curing can increase the particle size for easier separation, and hot water washing can remove unreacted ions.

[0024] Optionally, the low-temperature degumming step further includes dissolving 0.2-0.5% w / w phospholipase A1, 0.005-0.015% w / w rosemary extract, and 0.004-0.006% w / w fullerol-polyphenol composite powder in a citrate buffer solution with a concentration of 0.08-0.12M and a pH of 4.0-5.0 to obtain a mixed solvent.

[0025] In the above technical solution, the fullerol cage structure loads epigallocatechin gallate ester through π-π interaction, and the fullerol can quench singlet oxygen in chicken fat. 1 O2) cuts off lipid peroxidation free radicals, and epigallocatechin gallate can undergo phenol-phenol coupling with rosmarinic acid to regenerate antioxidant activity.

[0026] Optionally, the preparation steps of the fullerol-polyphenol composite powder are as follows: Fullerol is dissolved in phosphate buffer preheated to 55-65℃ at a concentration of 10 mg / mL to obtain solution A; epigallocatechin gallate is dissolved in phosphate buffer preheated to 55-65℃ at a concentration of 2.2 mg / mL to obtain solution B; solution A and solution B are mixed at a volume ratio of 1:1; the mixture is sonicated at 30-50 kHz for 1-2 hours at room temperature to obtain a reaction solution; the reaction solution is dialyzed with flowing deionized water for 2-3 hours; and then freeze-dried to obtain a brownish-brown fluffy powder.

[0027] In the above technical solution, phosphate buffer maintains a neutral environment, preventing the oxidation of epigallocatechin gallate. Ultrasonic cavitation disrupts fullerol aggregates, simultaneously driving the phenolic rings in epigallocatechin gallate to self-assemble with the fullerol spheres through π-π stacking into a complex. Unbound epigallocatechin gallate is removed by dialysis, while the complex is retained.

[0028] Secondly, the refining process for chicken fat provided by the present invention is prepared using the above-mentioned refining process for chicken fat.

[0029] Thirdly, the present invention provides a refining process for chicken oil to prepare chicken oil and its application in the food processing industry, pharmaceutical and health product industry, cosmetics industry, and pet food industry.

[0030] In summary, the present invention has at least one of the following beneficial technical effects:

[0031] 1. In the pretreatment step, vibrating sieving, based on the size exclusion effect, intercepts solid impurities (bone debris, connective tissue) and removes large particles. At 50℃, the viscosity of the oil decreases, Brownian motion is enhanced, the initial aggregation state of the colloidal particles is disrupted, creating a uniform reaction interface for enzymatic hydrolysis and improving degumming efficiency.

[0032] 2. In the low-temperature degumming step, phospholipase A1 can specifically cleave the Sn-1 ester bond of phospholipid molecules, converting non-hydrated phospholipids (β-phospholipids) into lysophospholipids, greatly enhancing water solubility. Rosemary extract can inhibit oxidation, and its oxalic acid can chelate metal ions (Fe). 2+ / Cu + ), blocking the chain reaction of lipid peroxidation free radicals.

[0033] 3. During the deacidification and decolorization steps, the sulfonic acid groups (-SO3H) on the membrane surface ionize to generate a negative charge, and the free fatty acids dissociate into RCOO at pH 5.0. - They are trapped due to the repulsion of the negative charge of the membrane. The membrane pore size is 0.5 nm, which can physically trap carotenoids and chlorophyll derivatives.

[0034] 4. In low-temperature deodorization, nitrogen gas generates bubbles with a diameter of 50-200 μm, creating a gas-liquid interface area of ​​2000 m² / m³. Volatile odor compounds (aldehydes, ketones) diffuse from the oil phase into the bubbles according to Henry's Law. The rate of trans fatty acid formation decreases at 180℃.

[0035] 5. In ceramic membrane filtration, grease flows tangentially across the membrane surface at a speed of 1-3 m / s for cross-flow sieving. Shear force peels off the filter cake layer, and 0.2 μm pore size traps colloidal particles and thermal aggregates for deep impurity removal. Detailed Implementation

[0036] The present invention will be further described in detail below with reference to the embodiments.

[0037] All materials used in the following examples are available for purchase on the market.

[0038] Example 1: A refining process for chicken fat

[0039] The refining process includes the following steps:

[0040] S1. Pretreatment: Chicken feather oil is passed through an 80-mesh vibrating screen, the oil temperature is raised to 45℃, and stirred at 30r / min for 12min.

[0041] S2. Low-temperature degumming: Based on the weight of crude oil, 0.02% w / w phospholipase A1 and 0.015% w / w rosemary extract are dissolved in a 0.08M citrate buffer solution with a pH of 4.0-5.0 to obtain a mixed solvent. The mixed solvent is preheated to 45°C, and then added to the pretreated chicken feather oil. The mixture is stirred at a low speed of 30 r / min for 35 min, and then heated to 80°C and held for 8 min to inactivate the enzyme, thus obtaining enzymatically hydrolyzed oil.

[0042] S3. Deacidification and decolorization: Under the conditions of pressure 1MPa, temperature 45℃, and pH 4.5-5.0, the enzymatically hydrolyzed oil is tangentially circulated through the surface of the sulfonated polyethersulfone nanofiltration membrane at a flow rate of 1.5m / s, with a single pass time of 10min, and the permeate oil is collected.

[0043] S4. Low-temperature deodorization: The temperature of the permeated oil is raised to 175°C, and nitrogen microbubbles are introduced into the oil under a pressure of 9 kPa. The reaction is carried out for 20 minutes to obtain deodorized oil.

[0044] S5. Ceramic membrane filtration: Under conditions of 0.5 MPa and 55°C, the deodorized oil is filtered tangentially through a 0.2 μm Al2O3 ceramic membrane at a speed of 1 m / s to obtain chicken oil #1.

[0045] The preparation steps of the sulfonated polyethersulfone nanofiltration membrane are as follows: Polyethersulfone particles are immersed in concentrated sulfuric acid at a liquid-to-solid ratio of 20:1 and magnetically stirred at 200 r / min and 40°C for 90 min. The reaction solution is then poured into ice water to terminate the reaction. The sulfonated polyethersulfone is filtered and washed with water until neutral. It is then dried at 50°C. The sulfonated polyethersulfone is dissolved in N,N-dimethylacetamide at a concentration of 18% w / w and stirred at 50°C until a transparent viscous liquid is obtained, which is then cast onto a glass plate and immediately immersed in room temperature deionized water for 30 s to solidify. The membrane is then transferred to a 40°C water bath for 1 h and then dried in a 60°C oven for 2 h.

[0046] Example 2: A refining process for chicken fat

[0047] The refining process includes the following steps:

[0048] S1. Pretreatment: Chicken feather oil is passed through a 100-mesh vibrating screen, the oil temperature is raised to 50℃, and stirred at 50r / min for 8min;

[0049] S2. Low-temperature degumming: Based on the weight of crude oil, 0.05% w / w phospholipase A1 and 0.015% w / w rosemary extract are dissolved in a 0.1M citrate buffer solution with a pH of 4.0-5.0 to obtain a mixed solvent. The mixed solvent is preheated to 48°C, and then added to the pretreated chicken feather oil. The mixture is stirred at a low speed of 50 r / min for 25 min, and then heated to 90°C and held for 3 min to inactivate the enzyme, thus obtaining enzymatically hydrolyzed oil.

[0050] S3. Deacidification and decolorization: Under the conditions of pressure 2MPa, temperature 45-55℃, and pH 4.5-5.0, the enzymatically hydrolyzed oil is tangentially circulated through the surface of the sulfonated polyethersulfone nanofiltration membrane at a flow rate of 2.5m / s, with a single pass time of 9min, and the permeate oil is collected.

[0051] S4. Low-temperature deodorization: The temperature of the permeated oil is raised to 180°C, and nitrogen microbubbles are introduced into the oil under a pressure of 11 kPa. The reaction is carried out for 10 minutes to obtain deodorized oil.

[0052] S5. Ceramic membrane filtration: Under conditions of 1.0 MPa and 65°C, the deodorized oil is filtered tangentially through a 0.2 μm Al2O3 ceramic membrane at a speed of 3 m / s to obtain chicken oil #2.

[0053] The preparation steps of the sulfonated polyethersulfone nanofiltration membrane are the same as in Example 1.

[0054] Example 3: A refining process for chicken fat

[0055] The refining process includes the following steps:

[0056] S1. Pretreatment: Chicken feather oil is passed through an 80-mesh vibrating screen, the oil temperature is raised to 50℃, and stirred at 40r / min for 10min.

[0057] S2. Low-temperature degumming: Based on the weight of crude oil, 0.03% w / w phospholipase A1 and 0.01% w / w rosemary extract are dissolved in a 0.1M citrate buffer solution with a pH of 4.0-5.0 to obtain a mixed solvent. The mixed solvent is preheated to 50°C, and then added to the pretreated chicken feather oil. The mixture is stirred at a low speed of 40 r / min for 30 min, and then heated to 85°C and held for 5 min to inactivate the enzyme, thus obtaining enzymatically hydrolyzed oil.

[0058] S3. Deacidification and decolorization: Under the conditions of pressure 1.5MPa, temperature 50℃, and pH 4.5-5.0, the enzymatically hydrolyzed oil is tangentially circulated through the surface of the sulfonated polyethersulfone nanofiltration membrane at a flow rate of 2m / s, with a single pass time of 6min, and the permeate oil is collected.

[0059] S4. Low-temperature deodorization: The temperature of the permeated oil is raised to 180°C, and nitrogen microbubbles are introduced into the oil under a pressure of 10 kPa. The reaction is carried out for 150 min to obtain deodorized oil.

[0060] S5. Ceramic membrane filtration: Under conditions of 0.8 MPa and 60°C, the deodorized oil is filtered tangentially through a 0.2 μm Al2O3 ceramic membrane at a speed of 2 m / s to obtain chicken oil #3.

[0061] The preparation steps of the sulfonated polyethersulfone nanofiltration membrane are the same as in Example 1.

[0062] Example 4: A refining process for chicken fat

[0063] The refining process includes the following steps:

[0064] S1. Pretreatment: Chicken feather oil is passed through an 80-mesh vibrating screen, the oil temperature is raised to 50℃, and stirred at 40r / min for 10min.

[0065] S2. Low-temperature degumming: Based on the weight of crude oil, 0.03% w / w phospholipase A1, 0.01% w / w rosemary extract, and 0.015% w / w phytate-zinc coordination polymer are dissolved in a 0.1M citrate buffer solution with a pH of 4.0-5.0 to obtain a mixed solvent. The mixed solvent is preheated to 50°C, and then added to the pretreated chicken feather oil. The mixture is stirred at a low speed of 40 r / min for 30 min, and then heated to 85°C and held for 5 min to inactivate the enzymes, thus obtaining enzymatically hydrolyzed oil.

[0066] S3. Deacidification and decolorization: Under the conditions of pressure 1.5MPa, temperature 50℃, and pH 4.5-5.0, the enzymatically hydrolyzed oil is tangentially circulated through the surface of the sulfonated polyethersulfone nanofiltration membrane at a flow rate of 2m / s, with a single pass time of 6min, and the permeate oil is collected.

[0067] S4. Low-temperature deodorization: The temperature of the permeated oil is raised to 180°C, and nitrogen microbubbles are introduced into the oil under a pressure of 10 kPa. The reaction is carried out for 150 min to obtain deodorized oil.

[0068] S5. Ceramic membrane filtration: Under conditions of 0.8 MPa and 60°C, the deodorized oil is filtered tangentially through a 0.2 μm Al2O3 ceramic membrane at a speed of 2 m / s to obtain chicken oil #4.

[0069] The preparation steps of the sulfonated polyethersulfone nanofiltration membrane are the same as in Example 1.

[0070] The preparation steps of the phytic acid-zinc coordination polymer are as follows: Sodium phytate is dissolved in hot water at 60°C to prepare a 0.1M solution A, and zinc acetate is dissolved in water at room temperature to prepare a 0.15M solution B. Solution B is slowly added dropwise to solution A, with a volume ratio of solution A to solution B of 1:1. A white flocculent precipitate is immediately formed under magnetic stirring at 500 r / min. After standing at 50°C for 10 min, it is centrifuged at 4000 rpm for 5 min, then washed three times with water at 50°C, and dried at 60°C for 2 h to obtain the phytic acid-zinc coordination polymer.

[0071] Example 5: A refining process for chicken fat

[0072] The refining process includes the following steps:

[0073] S1. Pretreatment: Chicken feather oil is passed through an 80-mesh vibrating screen, the oil temperature is raised to 50℃, and stirred at 40r / min for 10min.

[0074] S2. Low-temperature degumming: Based on the weight of crude oil, 0.03% w / w phospholipase A1, 0.01% w / w rosemary extract, and 0.005% w / w fullerol-polyphenol complex powder are dissolved in a 0.1M citrate buffer solution with a pH of 4.0-5.0 to obtain a mixed solvent. The mixed solvent is preheated to 50°C, and then added to the pretreated chicken feather oil. The mixture is stirred at a low speed of 40 r / min for 30 min, and then heated to 85°C and held for 5 min to inactivate the enzymes, thus obtaining enzymatically hydrolyzed oil.

[0075] S3. Deacidification and decolorization: Under the conditions of pressure 1.5MPa, temperature 50℃, and pH 4.5-5.0, the enzymatically hydrolyzed oil is tangentially circulated through the surface of the sulfonated polyethersulfone nanofiltration membrane at a flow rate of 2m / s, with a single pass time of 6min, and the permeate oil is collected.

[0076] S4. Low-temperature deodorization: The temperature of the permeated oil is raised to 180°C, and nitrogen microbubbles are introduced into the oil under a pressure of 10 kPa. The reaction is carried out for 150 min to obtain deodorized oil.

[0077] S5. Ceramic membrane filtration: Under conditions of 0.8 MPa and 60°C, the deodorized oil is filtered tangentially through a 0.2 μm Al2O3 ceramic membrane at a speed of 2 m / s to obtain chicken oil #5.

[0078] The preparation steps of the sulfonated polyethersulfone nanofiltration membrane are the same as in Example 1.

[0079] The preparation steps of the fullerol-polyphenol composite powder are as follows: Fullerol is dissolved in phosphate buffer preheated to 60°C at a concentration of 10 mg / mL to obtain solution A; epigallocatechin gallate is dissolved in phosphate buffer preheated to 60°C at a concentration of 2.2 mg / mL to obtain solution B; solution A and solution B are mixed at a volume ratio of 1:1 and sonicated at 40 kHz for 1.5 h at room temperature to obtain a reaction solution; the reaction solution is dialyzed with flowing deionized water for 2 h and freeze-dried to obtain a brownish-brown fluffy powder.

[0080] Example 6: A refining process for chicken fat

[0081] The refining process includes the following steps:

[0082] S1. Pretreatment: Chicken feather oil is passed through an 80-mesh vibrating screen, the oil temperature is raised to 50℃, and stirred at 40r / min for 10min.

[0083] S2. Low-temperature degumming: Based on the weight of crude oil, 0.03% w / w phospholipase A1, 0.01% w / w rosemary extract, 0.015% w / w phytate-zinc coordination polymer, and 0.005% w / w fullerol-polyphenol composite powder are dissolved in a 0.1M citrate buffer solution with a pH of 4.0-5.0 to obtain a mixed solvent. The mixed solvent is preheated to 50°C, and then added to the pretreated chicken feather oil. The mixture is stirred at a low speed of 40 r / min for 30 min, and then heated to 85°C and held for 5 min to inactivate the enzymes, thus obtaining enzymatically hydrolyzed oil.

[0084] S3. Deacidification and decolorization: Under the conditions of pressure 1.5MPa, temperature 50℃, and pH 4.5-5.0, the enzymatically hydrolyzed oil is tangentially circulated through the surface of the sulfonated polyethersulfone nanofiltration membrane at a flow rate of 2m / s, with a single pass time of 6min, and the permeate oil is collected.

[0085] S4. Low-temperature deodorization: The temperature of the permeated oil is raised to 180°C, and nitrogen microbubbles are introduced into the oil under a pressure of 10 kPa. The reaction is carried out for 150 min to obtain deodorized oil.

[0086] S5. Ceramic membrane filtration: Under conditions of 0.8 MPa and 60°C, the deodorized oil is filtered tangentially through a 0.2 μm Al2O3 ceramic membrane at a speed of 2 m / s to obtain chicken oil #6.

[0087] The preparation steps of the sulfonated polyethersulfone nanofiltration membrane are the same as in Example 1.

[0088] The preparation steps of the phytic acid-zinc coordination polymer are as follows: Sodium phytate is dissolved in hot water at 60°C to prepare a 0.1M solution A, and zinc acetate is dissolved in water at room temperature to prepare a 0.15M solution B. Solution B is slowly added dropwise to solution A, with a volume ratio of solution A to solution B of 1:1. A white flocculent precipitate is immediately formed under magnetic stirring at 500 r / min. After standing at 50°C for 10 min, it is centrifuged at 4000 rpm for 5 min, then washed three times with water at 50°C, and dried at 60°C for 2 h to obtain the phytic acid-zinc coordination polymer.

[0089] The preparation steps of the fullerol-polyphenol composite powder are as follows: Fullerol is dissolved in phosphate buffer preheated to 60°C at a concentration of 10 mg / mL to obtain solution A; epigallocatechin gallate is dissolved in phosphate buffer preheated to 60°C at a concentration of 2.2 mg / mL to obtain solution B; solution A and solution B are mixed at a volume ratio of 1:1 and sonicated at 40 kHz for 1.5 h at room temperature to obtain a reaction solution; the reaction solution is dialyzed with flowing deionized water for 2 h and freeze-dried to obtain a brownish-brown fluffy powder.

[0090] Comparative Example 1: The refining process of the comparative chicken fat provided in this comparative example is the same as that in Example 6, except that a pretreatment step is missing.

[0091] Comparative Example 2: The refining process of the comparative chicken oil provided in this comparative example is the same as that in Example 6, except that phospholipase A1 is missing in the low-temperature degumming step.

[0092] Comparative Example 3: The refining process of the comparative chicken fat provided in this comparative example is the same as that in Example 6, except that rosemary extract is missing in the low-temperature degumming step.

[0093] Comparative Example 4: The refining process of the comparative chicken oil provided in this comparative example is the same as that in Example 6, except that phospholipase A2 is used instead of phospholipase A1 in the low-temperature degumming step.

[0094] Comparative Example 5: The refining process of the comparative chicken oil provided in this comparative example is the same as that in Example 6, except that vitamin E (tocopherol) is used instead of rosemary extract in the low-temperature degumming step.

[0095] Comparative Example 6: The refining process of the comparative chicken oil provided in this comparative example is the same as that in Example 6, except that a common nanofiltration membrane is used instead of a sulfonated polyethersulfone nanofiltration membrane in the deacidification and decolorization step.

[0096] Comparative Example 7: The refining process of the comparative chicken oil provided in this comparative example is the same as that in Example 6, except that: low temperature deodorization step: the temperature of the permeated oil is raised to 180°C, nitrogen gas is introduced into the oil under a pressure of 10 kPa, and the reaction is carried out for 150 min to obtain deodorized oil.

[0097] Chicken oils #1-#6 prepared by the refining process of chicken oils in Examples 1-6 and comparative chicken oils D1-D7 prepared by the refining process of comparative chicken oils in Examples 1-7 were tested for oxidative stability, acid value control content, trans fatty acid content, and phospholipid residue rate. The test results are shown in Table 1. Among them, the oxidation stability was measured by the Schall oven method (110℃) to determine the oxidation induction period.

[0098] Table 1

[0099] Example performance Oxidation induction period (h) Acid value controlled content (mgKOH / g) Trans fatty acid content (%) Phospholipid residue (ppm) Example 1 36 0.32 0.11 10.2 Example 2 37 0.30 0.10 10.1 Example 3 39 0.29 0.09 9.8 Example 4 42 0.25 0.07 9.2 Example 5 44 0.23 0.06 8.9 Example 6 47 0.20 0.04 8.3 Comparative Example 1 34 0.35 0.15 10.5 Comparative Example 2 33 0.37 0.18 12.9 Comparative Example 3 22 0.41 0.22 11.3 Comparative Example 4 35 0.37 0.15 11.8 Comparative Example 5 25 0.39 0.17 10.7 Comparative Example 6 33 0.38 0.21 10.5 Comparative Example 7 34 0.34 0.13 10.0

[0100] The test data from Examples 1-3 in Table 1, especially the data from Example 3, show that the chicken oil obtained by setting the parameters in the refining process of chicken oil has excellent performance.

[0101] Compared with Examples 3 and 5, Examples 4 and 6 respectively added a phytic acid-zinc coordination polymer in the low-temperature degumming step. Chicken oil #4 prepared by the refining process of Example 4 showed improved properties compared to chicken oil #3 prepared by the refining process of Example 3. Similarly, chicken oil #6 prepared by the refining process of Example 6 showed improved properties compared to chicken oil #5 prepared by the refining process of Example 5. This is because the phytic acid in the phytic acid-zinc coordination polymer can chelate Fe. 3+ / Cu 2+ It blocks metal-catalyzed oxidation, including Zn. 2+ It can activate the ortho-dihydroxyl groups of rosmarinic acid, enhance the scavenging rate of ·OH, and synergistically enhance antioxidant activity with rosemary extract.

[0102] Compared to Example 3, Example 5 incorporated fullerol-polyphenol composite powder in the low-temperature degumming step. The chicken oil #5 prepared using the refining process of Example 5 showed improved properties compared to chicken oil #3 prepared using the refining process of Example 3. This is because the fullerol cage structure loads epigallocatechin gallate esters through π-π interactions, allowing fullerol to quench singlet oxygen in the chicken oil. 1 O2) cuts off lipid peroxidation free radicals, and epigallocatechin gallate can undergo phenol-phenol coupling with rosmarinic acid to regenerate antioxidant activity.

[0103] Compared to Example 6, Comparative Example 1 lacked a pretreatment step, resulting in a decrease in the properties of the comparative chicken oil obtained in Comparative Example 1. This is because the vibrating sieving in the pretreatment step, based on the size exclusion effect, intercepted solid impurities (bone debris, connective tissue) and removed large particles. At 50°C, the viscosity of the oil decreased, Brownian motion increased, and the initial aggregated state of the colloids was disrupted, creating a uniform reaction interface for enzymatic hydrolysis and improving degumming efficiency.

[0104] Compared with Example 6, Comparative Example 2 lacked phospholipase A1 in the low-temperature degumming step, which led to a decrease in the various properties of the comparative chicken oil obtained in Comparative Example 2. This is because phospholipase A1 can specifically cleave the Sn-1 ester bond of phospholipid molecules, converting non-hydrated phospholipids (β-phospholipids) into lysophospholipids, which greatly enhances water solubility.

[0105] Compared to Example 6, Comparative Example 3 lacked rosemary extract in the low-temperature degumming step, resulting in a decrease in all properties of the comparative chicken fat obtained in Comparative Example 3. This is because rosemary extract can inhibit oxidation, and its oxalic acid can chelate metal ions (Fe). 2+ / Cu + ), blocking the chain reaction of lipid peroxidation free radicals.

[0106] Compared with Example 6, Comparative Example 4 used phospholipase A2 instead of phospholipase A1 in the low-temperature degumming step, which resulted in a decrease in the performance of the comparative chicken oil obtained in Comparative Example 4. This is because although phospholipase A2 and phospholipase A1 belong to the same phospholipase family, phospholipase A2 hydrolyzes the ester bond at the Sn-2 position of phospholipids, which significantly reduces the degumming efficiency.

[0107] Compared with Example 6, Comparative Example 5 used vitamin E (tocopherol) instead of rosemary extract in the low-temperature degumming step, which resulted in a decrease in the properties of the comparative chicken oil obtained in Comparative Example 5. The reason is that although vitamin E can provide hydrogen atoms to interrupt the free radical chain reaction and remove lipid peroxide free radicals (ROO·), its oxidation potential is lower than that of rosmarinic acid, its reaction activity is weak, it cannot effectively chelate metal ions, and it is easily decomposed at high temperatures above 80°C.

[0108] Compared to Example 6, Comparative Example 6 used a regular nanofiltration membrane instead of a sulfonated polyethersulfone nanofiltration membrane in the deacidification and decolorization step. This resulted in a decrease in all properties of the comparative chicken oil obtained in Comparative Example 6. The reason is that the sulfonic acid groups (-SO3H) on the surface of the sulfonated polyethersulfone nanofiltration membrane ionize to generate a negative charge, and the free fatty acids dissociate into RCOO at pH 5.0. - They are trapped due to the repulsion of the negative charge of the membrane. The membrane pore size is 0.5 nm, which can physically trap carotenoids and chlorophyll derivatives.

[0109] Compared with Example 6, Comparative Example 7 introduced nitrogen gas instead of nitrogen microbubbles in the low-temperature deodorization step, which caused the performance of the comparative chicken oil obtained in Comparative Example 7 to decline. This is because nitrogen gas generates bubbles with a diameter of 50-200 μm, forming a gas-liquid interface area of ​​2000 m² / m³. Volatile odor substances (aldehydes, ketones) diffuse from the oil phase into the bubbles according to Henry's Law.

[0110] The above are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A refining process for chicken fat, characterized in that, The refining process includes the following steps: Pretreatment: Chicken feather oil is passed through an 80-100 mesh vibrating screen, the oil temperature is raised to 45-50℃, and stirred at 30-50 r / min for 8-12 min; Low-temperature degumming: Based on the weight of crude oil, 0.02-0.05% w / w phospholipase A1, 0.005-0.015% w / w rosemary extract, 0.01-0.02% w / w phytate-zinc coordination polymer, and 0.004-0.006% w / w fullerol-polyphenol complex powder are dissolved in a 0.08-0.12M citrate buffer solution with a pH of 4.0-5.0 to obtain a mixed solvent. The mixed solvent is preheated to 45-50℃, and then added to the pretreated chicken feather oil. The mixture is stirred at a low speed of 30-50 r / min for 25-35 min, and then heated to 80-90℃ and held for 3-8 min to inactivate the enzyme, thus obtaining enzymatically hydrolyzed oil. Deacidification and decolorization: Under the conditions of pressure 1-2MPa, temperature 45-50℃, and pH 4.5-5.0, the enzymatically hydrolyzed oil is tangentially circulated through the surface of the sulfonated polyethersulfone nanofiltration membrane at a flow rate of 1.5-2.5m / s, with a single pass time ≤10min, and the permeate oil is collected; Low-temperature deodorization: The temperature of the permeated oil is raised to 175-180℃, and nitrogen microbubbles are introduced into the oil under a pressure of 9-11kPa. The reaction is carried out for 10-20 minutes to obtain deodorized oil. Ceramic membrane filtration: Under conditions of 0.5-1.0 MPa and 55-65℃, the deodorized oil is filtered tangentially through a 0.2μm Al2O3 ceramic membrane at a speed of 1-3 m / s to obtain the chicken oil; The preparation steps of the sulfonated polyethersulfone nanofiltration membrane are as follows: Polyethersulfone particles are immersed in concentrated sulfuric acid at a liquid-to-solid ratio of 18-22:1 and magnetically stirred at 100-300 r / min and 35-45℃ for 80-100 min. The reaction solution is then poured into ice water to terminate the reaction. The sulfonated polyethersulfone is filtered and washed with water until neutral. It is then dried at 55-65℃. The sulfonated polyethersulfone is dissolved in N,N-dimethylacetamide at a concentration of 18% w / w and stirred at 55-65℃ until a transparent viscous liquid is obtained. The casting solution is then cast onto a glass plate and immediately immersed in room temperature deionized water for 25-35 s to solidify. The membrane is then transferred to a water bath at 35-45℃ for 0.8-1.2 h and then dried in an oven at 55-65℃ for 1-3 h. The preparation steps of the phytic acid-zinc coordination polymer are as follows: Sodium phytate is dissolved in hot water at 55-65℃ to prepare a 0.1M solution A, and zinc acetate is dissolved in water at room temperature to prepare a 0.15M solution B; solution B is slowly added dropwise to solution A, and the volume ratio of solution A to solution B is 1:

1. Under magnetic stirring at 400-600 r / min, a white flocculent precipitate is immediately generated. After standing at 55-65℃ for 8-12 min, it is centrifuged at 3500-4500 rpm for 5-8 min, then washed 2-3 times with water at 55-65℃, and dried at 55-65℃ for 1-3 h to obtain the phytic acid-zinc coordination polymer. The preparation steps of the fullerol-polyphenol composite powder are as follows: Fullerol is dissolved in phosphate buffer preheated to 55-65℃ with a concentration of 10 mg / mL to obtain solution A; epigallocatechin gallate is dissolved in phosphate buffer preheated to 55-65℃ with a concentration of 2.2 mg / mL to obtain solution B; solution A and solution B are mixed at a volume ratio of 1:1 and sonicated at 30-50 kHz for 1-2 h at room temperature to obtain a reaction solution; the reaction solution is dialyzed with flowing deionized water for 2-3 h and freeze-dried to obtain a brownish-brown fluffy powder.

2. A type of chicken fat, characterized in that, It is prepared using the refining process of chicken oil as described in claim 1.