Preparation method of antioxidant, fresh-keeping and shelf-life-prolonging high-oleic-acid peanut oil

Abstract

The invention relates to the technical field of edible oil production, in particular to a preparation method of antioxidant, fresh-keeping and shelf-life-prolonging high-oleic-acid peanut oil, which comprises the working procedures of raw material pretreatment, low-temperature gradient oxygen isolation squeezing, colloid synergetic low-temperature degumming, in-situ chelating oxidation resistance, low-temperature light-shielding synergetic curing and sterile and anaerobic filling. Microwave-hot air two-stage combined passivation, three-stage oxygen-isolation temperature-control squeezing and a natural antioxidant system compounded in-situ chelation technology are adopted, a full-process oxidation dynamic regulation and control algorithm and a shelf life prediction model are matched, and full-process low-temperature oxygen-isolation control is achieved. According to the method, the lipoxygenase passivation rate is larger than or equal to 98.5%, the oleic acid retention rate is larger than or equal to 96.5%, the normal-temperature light-tight sealing shelf life of the finished product is larger than or equal to 24 months, the grease oxidation path is blocked from the source, and the method is suitable for large-scale standardized production of the high-oleic-acid peanut oil.

Description

Technical Field

[0001] This invention relates to the field of edible oil production technology, specifically to a method for preparing high-oleic peanut oil with antioxidant properties to preserve freshness and extend shelf life. Background Technology

[0002] High-oleic peanut oil is made from peanuts with an oleic acid content of ≥75%. Compared to ordinary peanut oil, it has a higher oleic acid content, a more balanced composition of unsaturated fatty acids, and significantly improved oxidative stability. It also possesses superior nutritional properties, making it a core direction for quality upgrading in the edible oil industry in recent years. However, in actual production and application, high-oleic peanut oil still faces problems such as a high risk of oxidative deterioration during processing, low retention of natural nutrients, difficulty in extending shelf life at room temperature, and significant flavor deterioration in the later stages of storage. The core reason is that existing preparation technologies cannot prevent the initiation and transmission of the chain reaction of oil oxidation throughout the entire processing flow. Furthermore, it is difficult to balance the relationship between oil extraction efficiency, nutrient retention, and antioxidant preservation effects, becoming a key technological bottleneck restricting the large-scale development of the high-oleic peanut oil industry.

[0003] Currently, there are existing research and publicly available solutions for the antioxidant preservation preparation technology of high-oleic peanut oil. Among them, patent document CN202510568697 discloses a method for preparing high-oleic peanut oil. This method uses high-oleic peanuts as raw materials and achieves the preparation of high-oleic peanut oil through a process of raw material selection, high-temperature roasting, physical pressing, multi-stage refining, and the addition of antioxidants at the end. By controlling the roasting temperature and pressing parameters, it improves the peanut oil yield and the oleic acid retention rate in the finished product, thereby improving the basic quality of high-oleic peanut oil to a certain extent.

[0004] However, the applicant discovered through research that the technical solution disclosed in prior art document CN202510568697 still has several unresolved technical defects. First, while prior art document CN202510568697 uses a high-temperature roasting process and a conventional high-temperature refining process to improve oil extraction efficiency and flavor, the high-temperature treatment process causes a significant loss of natural antioxidant active ingredients such as endogenous γ-tocopherol and phytosterols in peanuts. At the same time, it cannot completely inactivate endogenous pro-oxidative enzymes such as lipoxygenase and phospholipase. These endogenous enzymes will still catalyze hydrolysis and oxidation reactions of the oil during subsequent storage, leading to a decrease in product storage stability. Secondly, the comparative document CN202510568697 only adds antioxidants at the end of the refining process, without setting up oxygen isolation protection and oxidation control measures throughout the entire preparation process. The oil has already come into full contact with oxygen and undergone preliminary oxidation in multiple processes such as pressing and refining. The initial peroxide value of crude oil and semi-finished oil products is relatively high. Relying solely on adding antioxidants at the end cannot fundamentally block the oxidation reaction path and is difficult to achieve a long-lasting antioxidant preservation effect.

[0005] Furthermore, the antioxidant scheme adopted in the prior art document CN202510568697 is a conventional single or simple compound antioxidant system. It does not design a multi-component synergistic antioxidant system specifically for the oxidation characteristics of high-oleic peanut oil, nor does it utilize chelation technology to remove free iron, copper, and other metal ions from the oil. These free metal ions are the core catalysts in the chain reaction of oil oxidation, and cannot be completely removed through conventional degumming processes alone. This limits the effectiveness of its antioxidant system, making it difficult for the finished product to achieve a shelf life of more than 24 months under normal temperature storage conditions. In the later stages of storage, quality deterioration problems such as excessive peroxide value, increased acid value, and rancidity are prone to occur. Simultaneously, prior art document CN202510568697 lacks a real-time monitoring and feedback control mechanism for the oxidation degree throughout the entire preparation process, and it does not construct a precise shelf-life prediction model based on oxidation kinetics. This makes it impossible to dynamically control the degree of oil oxidation during processing, making it difficult to guarantee the quality uniformity of different batches of products, and failing to provide accurate data support for product shelf-life management. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing high-oleic peanut oil with antioxidant preservation and extended shelf life, so as to solve the problem mentioned in the background art that it is difficult to achieve long-term antioxidant preservation effect when preparing high-oleic peanut oil.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A method for preparing high-oleic peanut oil with antioxidant properties and extended shelf life includes the following steps: S1. Raw material pretreatment process: Microwave-hot air dual-stage passivation process is adopted to perform targeted enzyme activation passivation and gradient drying on the shelled and graded high oleic peanut kernels. This process targets and passivates endogenous prooxidant enzymes such as lipoxygenase and phospholipase in peanut kernels, while retaining the natural antioxidant active ingredients such as γ-tocopherol and phytosterols in peanuts to the greatest extent, thus obtaining pretreated peanut kernels. S2, Low-temperature gradient oxygen-free pressing process: The pretreated peanut kernels obtained in S1 are sent into a twin-screw press with full nitrogen micro-positive pressure oxygen-free protection. The three-stage gradient pressure increase and temperature control pressing process is adopted to complete the oil pressing and extraction in a low-temperature oxygen-free environment, inhibiting the oxidative degradation of oleic acid and the initiation of free radical chain reaction during the pressing process, and obtaining high oleic acid peanut crude oil. S3, Colloidal Synergistic Low-Temperature Degumming Process: The high-oleic peanut oil obtained in S2 is placed in a closed oxygen-free reaction system, and a composite colloidal degumming agent is used for low-temperature hydration synergistic chelation degumming treatment to remove colloidal impurities, free metal ions and oxidation precursors from the crude oil. After centrifugation, degummed clear oil is obtained. S4, In-situ Chelation Antioxidant Process: The degummed oil obtained in S3 is placed in a sealed reaction vessel protected from light and nitrogen throughout the process. A composite natural antioxidant system, which combines natural antioxidant components and metal ion chelating agents, is added. Under low temperature and constant temperature conditions, the in-situ chelation reaction and the anchoring of the antioxidant active groups in the oil phase are completed, and an endogenous long-term antioxidant protection system for the oil is constructed to obtain an antioxidant pretreated oil. S5. Low-temperature and light-protected synergistic ripening process: The antioxidant pretreated oil obtained in S4 is placed in a closed environment with low temperature, light protection and nitrogen protection throughout the process for constant temperature static ripening treatment to remove trace wax, colloidal precipitates and volatile odor substances from the oil. After ripening, it is filtered through sterilization-grade precision to obtain refined high oleic acid peanut oil. S6. Aseptic and oxygen-free filling process: The refined high oleic peanut oil obtained from S5 is filled and sealed in a Class 100 clean, low-temperature, light-proof, and airtight environment with nitrogen replacement to minimize the residual oxygen content in the finished product packaging and block the oxidation reaction path during storage. The cumulative contact time between oil and oxygen in the entire preparation process is ≤12%, and the highest ambient temperature of materials in contact throughout the process is ≤65℃.

[0008] Preferably, the specific steps of the microwave-hot air dual-stage passivation process in step S1 are as follows: First, the shelled and graded high-oleic peanut kernels are placed in a microwave device with a microwave frequency of 2450MHz and a power density of 0.8-1.2W / g, and subjected to low-temperature passivation treatment for 90-150s, so that the core temperature of the peanut kernels rises uniformly to 55-60℃; then, the microwave-passivated peanut kernels are immediately placed in a closed-loop hot air drying device with a hot air temperature of 45-50℃ and a wind speed of 1.0-1.5m / s, and subjected to gradient drying for 20-30min to obtain pretreated peanut kernels with a moisture content of 3.5%-4.5% and a water activity ≤0.45; the passivation rate of lipoxygenase in step S1 needs to meet the following calculation formula: ; In the formula, The inactivation rate of lipoxygenase is expressed as % . The enzyme activity of lipoxygenase in peanut kernels after passivation treatment is expressed in U / g. The initial enzyme activity of lipoxygenase in untreated peanut kernels is expressed in U / g; and the process in step S1 must meet the following requirements. The retention rate of endogenous γ-tocopherol is ≥92%, and the retention rate of phytosterols is ≥90%.

[0009] Preferably, the three-stage gradient pressure-controlled pressing process in step S2 involves filling the entire process with food-grade nitrogen gas with a purity ≥99.99% to maintain a slight positive pressure of 0.02-0.05 MPa within the pressing chamber. The specific parameters for the three stages are as follows: First stage pressing temperature 35-40℃, pressing pressure 8-12 MPa, material residence time 15-20 s, to achieve initial cell wall disruption and pre-extraction of peanut kernels; Second stage pressing temperature 40-45℃, pressing pressure 18-22 MPa, material residence time 25-30 s, to achieve gentle extraction of the main oil; Third stage pressing temperature 45-50℃, pressing pressure 25-30 MPa, material residence time 35-40 s, to achieve deep extraction of residual oil. The oleic acid retention rate in step S2 must meet the following kinetic calculation formula: ; In the formula, Oleic acid retention rate, in percentages (%) The pre-exponential factor for the oleic acid oxidation reaction is 3.2 × 10⁻⁶. 5 min -1 ; Total pressing time, in minutes; The activation energy for the oxidation of oleic acid is 42.3 kJ / mol. This is the universal gas constant, with a value of 8.314 J / (mol·K); The temperature of the pressing system is expressed in Kelvin; and step S2 must satisfy the following requirements. The residual oil content of the oil cake is ≤6.5%, and the initial peroxide value of the crude oil is ≤0.03g / 100g.

[0010] Preferably, the colloidal synergistic low-temperature degumming process in step S3 is as follows: the high-oleic peanut oil obtained in S2 is heated to 38-42℃, and 0.15%-0.3% of the crude oil mass of a composite colloidal degumming agent is added under nitrogen protection. The mixture is stirred at a constant temperature at 120-180 r / min for 25-35 min to allow the composite colloidal degumming agent to fully chelate and flocculate with the phospholipids and free metal ions in the crude oil. Then, the mixture is centrifuged in a closed system at 4500-5500 r / min for 10-15 min, and the upper clear oil is taken to obtain degummed oil. The composite colloidal degumming agent is composed of soybean lecithin, chitosan oligosaccharide and trisodium citrate in a mass ratio of 2:1:1. After degumming, the phospholipid content in the oil is ≤30mg / kg, the hydration degumming rate is ≥99%, and the free iron ion content in the oil is ≤0.1mg / kg.

[0011] Preferably, the in-situ chelation antioxidant process in step S4 is as follows: the degummed oil obtained in S3 is placed in a sealed reactor protected from light and nitrogen throughout the process, maintaining the oxygen content in the reactor at ≤0.3%, and the temperature is raised to 42-48℃. A composite natural antioxidant system at 0.08%-0.25% of the degummed oil mass is added, and the mixture is stirred at a constant temperature of 80-120 r / min for 40-60 min to complete the in-situ chelation of metal ions and the stable dispersion and anchoring of the antioxidant active groups in the oil phase, resulting in an antioxidant pretreated oil. The composite natural antioxidant system is composed of rosemary extract (with oxalic acid content ≥60%), tea polyphenol palmitate, γ-tocopherol, and sodium phytate in a mass ratio of 3:2:1:1. The synergistic antioxidant enhancement coefficient of the composite system must satisfy the following calculation formula: ; In the formula, The synergistic antioxidant enhancement coefficient; , , , The figures represent the DPPH half-maximal inhibitory concentrations (IC50) of rosemary extract, tea polyphenol palmitate, γ-tocopherol, and sodium phytate when used alone, in mg / L. The DPPH radical scavenging half-maximal inhibitory concentration (IC50) is the concentration of free radicals inhibited when the composite system is used in combination, expressed in mg / L; and the composite system must meet the following requirements. The oxidation induction period of oils at 120℃ is ≥28h.

[0012] Preferably, the low-temperature light-protected synergistic ripening process in step S5 is as follows: the antioxidant pretreated oil obtained in S4 is placed in a sealed ripening tank at a temperature of 10-14℃, protected from light throughout the process, and under nitrogen protection, maintaining the oxygen content of the system at ≤0.3%, and allowed to ripen for 48-72 hours. No heating or stirring is performed during the ripening process. After ripening, a 0.22μm sterile filter membrane is used for negative pressure filtration under a slight positive pressure of nitrogen to remove trace amounts of wax, colloids, and solid impurities precipitated from the oil, resulting in refined high-oleic peanut oil. The wax content in the oil after ripening is ≤5mg / kg, and the solid fat content at 0℃ for 5.5 hours is ≤0.02%.

[0013] Preferably, the aseptic and anaerobic filling process in step S6 is as follows: the refined high oleic peanut oil obtained in S5 is filled anaerobically in a clean, light-proof, and low-temperature (8-12℃) sealed filling room. Before filling, the food-grade packaging container is vacuumed and purged with nitrogen at a purity of ≥99.99% for more than 3 times to replace the headspace oxygen. After replacement, the residual oxygen content in the headspace of the container is ≤0.2%. After filling, the container is immediately sealed in a nitrogen atmosphere. The residual oxygen content in the headspace of the finished product packaging is ≤0.15%, and the sealing leakage rate is ≤0.01%.

[0014] Preferably, the preparation method further includes a real-time monitoring and feedback control algorithm for the oxidation degree of all processes from S1 to S6. The algorithm uses peroxide value (POV) and acid value (AV) as core monitoring indicators, sets online detection nodes at the discharge port of each process, and calculates the process control coefficient using the following formula to adjust the temperature, oxygen content, and reaction time of each process in real time: ; In the formula, This is the process control coefficient; This refers to the peroxide value measured in real time for the corresponding process, expressed in g / 100g. A threshold value for peroxide value is set for this process, in g / 100g. The acid value is measured in real time for the corresponding process, and the unit is mgKOH / g; A threshold value is set for the acid value in this process, in mgKOH / g; when When this occurs, a process parameter early warning and control mechanism is triggered, reducing the temperature of the corresponding process system by 10%-15%, supplementing nitrogen to reduce the oxygen content of the system by more than 50%, until the real-time detection... .

[0015] Preferably, the preparation method further includes a precise shelf-life prediction model based on the finished product obtained in steps S1 to S6. This model is constructed based on the Arrhenius oxidation kinetic equation, and the specific formula is as follows: ; In the formula, The shelf life of the finished product is measured in months under normal temperature and light-protected conditions at 25°C. The peroxide value limit for the end of the shelf life of peanut oil is set at 0.15g / 100g. This is the initial peroxide value of the finished product, expressed in g / 100g. The pre-exponential factor for the oxidation reaction is 2.17 × 10⁻⁶. 6 g / (100g·month); The activation energy for the oxidation of the finished oil is taken as 58.6 kJ / mol; This is the universal gas constant, with a value of 8.314 J / (mol·K); The thermodynamic temperature for room temperature storage is 298.15K; the relative deviation between the shelf life predicted by the model and the actual shelf life measured by accelerated testing is ≤4.5%.

[0016] Preferably, the high-oleic peanut oil obtained through steps S1 to S6 has an oleic acid content ≥75%, a linoleic acid content ≤8%, an initial peroxide value ≤0.05g / 100g, an initial acid value ≤0.1mgKOH / g, no detectable aflatoxin B1, and a benzo[a]pyrene content ≤2μg / kg. Under sealed conditions at room temperature (25℃) protected from light, it has a shelf life ≥24 months, an end-of-shelf-life peroxide value ≤0.12g / 100g, an acid value ≤0.25mgKOH / g, no rancid odor, no flavor deterioration, and an oleic acid retention rate ≥94%.

[0017] Compared with the prior art, the beneficial effects of the present invention are: (1) This invention achieves efficient passivation of endogenous prooxidant enzymes such as lipoxygenase and phospholipase during the raw material processing stage through a low-temperature oxygen-isolated process design throughout the entire process, combined with a microwave-hot air dual-stage passivation process. At the same time, it avoids the destruction of natural antioxidant active ingredients in peanuts by traditional high-temperature processing processes, and effectively preserves endogenous active substances such as γ-tocopherol and phytosterols. The entire process strictly controls the contact time between oil and oxygen and the ambient temperature of material contact, inhibiting the initiation of the oil oxidation chain reaction from the source of processing, reducing the initial oxidation degree of peanut crude oil, and laying a stable foundation for subsequent long-term antioxidant treatment.

[0018] (2) This invention employs a process combining colloidal synergistic low-temperature degumming with in-situ chelation antioxidants. By using a compounded colloidal degumming agent, phospholipids, free metal ions, and other pro-oxidation precursors in crude oil are simultaneously removed, reducing the catalytic factors for oil oxidation during storage. The compounded natural antioxidant system achieves multi-component synergistic antioxidant effects. Through in-situ chelation reaction, the antioxidant active ingredients are stably dispersed and anchored in the oil phase, enhancing the oxidation induction period of the oil and constructing an endogenous long-lasting antioxidant protection system for the oil. This solves the limitations of single antioxidants and the quality control problems caused by the use of synthetic antioxidants.

[0019] (3) This invention further removes trace amounts of wax and solid impurities from the oil through low-temperature, light-protected synergistic ripening and aseptic, oxygen-free filling processes, reducing the risk of oxidation during finished product storage. The accompanying real-time monitoring and feedback control algorithm for the degree of oxidation throughout the entire process enables dynamic control of oil quality during processing, ensuring uniform and stable product quality across different batches. The shelf-life prediction model based on Arrhenius oxidation kinetics can accurately predict the shelf life of the finished product. The high-oleic peanut oil produced has a significantly extended shelf life under room temperature, light-protected, and sealed conditions, and its physicochemical indicators and flavor quality remain stable during the storage period, meeting the requirements of relevant national food safety standards. Attached Figure Description

[0020] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are explained in detail together with the embodiments of the invention, but do not constitute a limitation thereof.

[0021] Figure 1 This invention demonstrates the entire process of preparing high-oleic peanut oil, from raw material pretreatment to finished product bottling. Figure 2 This diagram illustrates the raw material pretreatment process and the low-temperature gradient oxygen-free pressing process of this invention. Figure 3 This diagram shows the colloidal synergistic low-temperature degumming process and the in-situ chelation and anti-oxidation process of the present invention. Figure 4 The diagram shows the low-temperature light-avoidance synergistic ripening process and the aseptic oxygen-free filling process of this invention. Detailed Implementation

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0023] like Figures 1-4 As shown, this invention uses low-temperature oxygen-free control throughout the entire process, combined with core processes such as targeted enzyme activation and passivation, colloid synergistic degumming, and in-situ chelation antioxidation, to completely block the oil oxidation reaction path, thereby maximizing the preservation of natural nutrients and active ingredients in high-oleic peanut oil, achieving long-lasting antioxidant preservation of the product, and significantly extending the shelf life at room temperature.

[0024] The following details the complete implementation steps of the preparation method of the present invention. All steps are carried out sequentially and continuously. The cumulative contact time between the oil and oxygen in the entire preparation process does not exceed 12%, and the highest ambient temperature of the materials in contact throughout the process does not exceed 65°C.

[0025] S1 Raw Material Pretreatment Process This process employs a microwave-hot air dual-stage passivation process to perform targeted enzyme activation passivation and gradient drying on shelled and graded high-oleic peanut kernels. First, high-oleic peanut raw materials with an oleic acid content of no less than 75% are selected. After shelling, impurity removal, and color sorting, moldy and broken particles are removed to obtain whole and uniform high-oleic peanut kernels. The peanut kernels are then fed into a microwave device with a microwave frequency of 2450MHz and a power density of 0.8 to 1.2W per gram. Low-temperature passivation is performed for 90 to 150 seconds, causing the core temperature of the peanut kernels to rise uniformly to 55 to 60℃, completing the targeted passivation of endogenous pro-oxidative enzymes such as lipoxygenase and phospholipase in the peanut kernels. After microwave passivation, the peanut kernels are immediately transferred to a closed-loop hot air drying device with a hot air temperature of 45 to 50℃ and an air velocity of 1.0 to 1.5 m / s, and gradient drying is performed for 20 to 30 minutes, ultimately yielding pre-treated peanut kernels with a moisture content of 3.5% to 4.5% and a water activity not exceeding 0.45.

[0026] The lipoxygenase inactivation rate in this process must meet the following calculation formula: ; In the formula, The inactivation rate of lipoxygenase is expressed as % . The enzyme activity of lipoxygenase in peanut kernels after passivation treatment is expressed in U per gram. The initial enzyme activity of lipoxygenase in untreated peanut kernels is expressed in U per gram. This process must meet the following requirements: lipoxygenase inactivation rate of not less than 98.5%, endogenous γ-tocopherol retention rate of not less than 92%, and phytosterol retention rate of not less than 90%.

[0027] S2 Low-Temperature Gradient Oxygen-Barrier Pressing Process The pretreated peanut kernels obtained from S1 are fed into a twin-screw press. The entire pressing process utilizes a slightly positive nitrogen pressure system for oxygen isolation. The food-grade nitrogen used is at least 99.99% pure, maintaining a slightly positive pressure of 0.02 to 0.05 MPa within the pressing chamber. This isolates oxygen from the material, inhibiting the oxidative degradation of oleic acid and the initiation of free radical chain reactions during pressing. This process employs a three-stage gradient pressure-controlled pressing technology, with the following specific parameter settings: The first stage sets the pressing temperature at 35 to 40°C, the pressing pressure at 8 to 12 MPa, and the material residence time at 15 to 20 seconds, completing the initial cell wall disruption and pre-extraction of oil from the peanut kernels; the second stage sets the pressing temperature at 40 to 45°C, the pressing pressure at 18 to 22 MPa, and the material residence time at 25 to 30 seconds, completing the gentle extraction of the main oil; the third stage sets the pressing temperature at 45 to 50°C, the pressing pressure at 25 to 30 MPa, and the material residence time at 35 to 40 seconds, completing the deep extraction of residual oil. After pressing, the cake and debris are removed by filtration to obtain high-oleic peanut oil.

[0028] The oleic acid retention rate in this process must meet the following kinetic calculation formula: ; In the formula, Oleic acid retention rate, in percentages (%) The pre-exponential factor for the oleic acid oxidation reaction is 3.2 × 10⁻⁶. 5 min -1 ; Total pressing time, in minutes; The activation energy for the oxidation of oleic acid is 42.3 kJ per mol. The universal gas constant is 8.314 J per mol per K. The temperature is the thermodynamic temperature of the pressing system, expressed in Kelvin. This process must meet the following requirements: oleic acid retention rate not less than 96.5%, residual oil content in cake not exceeding 6.5%, and initial peroxide value of crude oil not exceeding 0.03 g per 100 g.

[0029] S3 Colloid-Assisted Low-Temperature Degumming Process The high-oleic peanut oil obtained from S2 was placed in a closed, oxygen-free reaction system under nitrogen protection throughout the process. A composite colloid degumming agent was used for low-temperature hydration-synergistic chelation degumming treatment. First, the crude oil was heated to 38-42°C, and 0.15%-0.3% (by weight) of the composite colloid degumming agent was added. The stirring speed was set to 120-180 rpm, and the reaction was carried out at a constant temperature for 25-35 minutes. This allowed the composite colloid degumming agent to fully chelate and flocculate with the phospholipids and free metal ions in the crude oil, removing colloidal impurities, free metal ions, and oxidation precursors. After the reaction was complete, the material was transferred to a closed centrifuge and centrifuged at 4500-5500 rpm for 10-15 minutes. The supernatant was collected as the degummed clear oil.

[0030] The composite colloid degumming agent used in this process is a mixture of soybean lecithin, chitosan oligosaccharide, and trisodium citrate in a mass ratio of 2:1:1. After degumming, the phospholipid content in the oil does not exceed 30 mg per kg, the hydration degumming rate is not less than 99%, and the free iron ion content in the oil does not exceed 0.1 mg per kg.

[0031] S4 in-situ chelation antioxidant process The degummed oil obtained from S3 was placed in a sealed reactor protected from light and under nitrogen gas throughout the process. Nitrogen gas was continuously introduced to maintain the oxygen content in the reactor at no more than 0.3%. The degummed oil was heated to 42 to 48°C, and 0.08% to 0.25% of a composite natural antioxidant system by weight of the degummed oil was added. The stirring speed was set to 80 to 120 r per minute, and the reaction was carried out at a constant temperature for 40 to 60 minutes. This completed the in-situ chelation of metal ions and the stable dispersion and anchoring of antioxidant active groups in the oil phase, thus constructing an endogenous long-term antioxidant protection system for the oil and obtaining an antioxidant pretreated oil.

[0032] The composite natural antioxidant system used in this process is composed of rosemary extract, tea polyphenol palmitate, γ-tocopherol, and sodium phytate in a mass ratio of 3:2:1:1. The rosemary extract contains no less than 60% caryopsisic acid. The synergistic antioxidant enhancement coefficient of the composite system must meet the following calculation formula: ; In the formula, The synergistic antioxidant enhancement coefficient; , , , The figures represent the DPPH half-maximal inhibitory concentrations (IC50) of rosemary extract, tea polyphenol palmitate, γ-tocopherol, and sodium phytate when used alone, in mg per L. The DPPH half-maximal inhibitory concentration (ICP-C) for free radical scavenging when used in combination with other compound systems is expressed in mg per L. The compound system used in this process must have a synergistic antioxidant enhancement coefficient of not less than 1.9, and the treated oil must have an oxidation induction period of not less than 28 hours at 120°C.

[0033] S5 Low-Temperature Light-Proofing Co-Curing Process The antioxidant pretreated oil obtained from S4 was placed in a sealed maturation tank, maintaining low temperature, light protection, and nitrogen protection throughout the process. The maturation temperature was set at 10 to 14°C, and nitrogen was continuously introduced to maintain the oxygen content of the system at no more than 0.3%. The oil was allowed to mature for 48 to 72 hours without any heating or stirring, allowing trace waxes and colloidal precipitates to settle fully, while simultaneously removing volatile odor substances. After maturation, a 0.22μm sterile-grade filter membrane was used for negative pressure filtration under slightly positive nitrogen pressure to remove trace waxes, colloids, and solid impurities, yielding refined high-oleic peanut oil.

[0034] After aging, the wax content in the oil does not exceed 5 mg per kg, and the solid fat content under the condition of standing at 0℃ for 5.5 hours does not exceed 0.02%.

[0035] S6 Aseptic and Anaerobic Filling Process The refined high-oleic peanut oil obtained from S5 was sent to a Class 100 clean, light-proof, low-temperature sealed filling room for anaerobic filling, with the filling environment temperature set at 8 to 12°C. Before filling, the food-grade packaging containers were subjected to at least three vacuum-nitrogen-filling cycles using food-grade nitrogen with a purity of not less than 99.99%, ensuring that the headspace oxygen content in the container after replacement did not exceed 0.2%. After filling, the containers were immediately sealed under a nitrogen atmosphere, ensuring that the headspace oxygen content in the finished product packaging did not exceed 0.15% and the sealing leakage rate did not exceed 0.01%, ultimately yielding the finished high-oleic peanut oil.

[0036] The preparation method of this invention also includes a real-time monitoring and feedback control algorithm for the oxidation degree of all processes from S1 to S6. The algorithm uses peroxide value (POV) and acid value (AV) as core monitoring indicators, sets online detection nodes at the discharge port of each process, collects the oil quality data of the corresponding process in real time, and calculates the process control coefficient using the following formula to adjust the temperature, oxygen content, and reaction time of each process in real time: ; In the formula, This is the process control coefficient; This refers to the peroxide value measured in real time for the corresponding process, expressed in grams per 100g. A threshold value for peroxide value is set for this process, in grams per 100g; This refers to the acid value measured in real time for the corresponding process, expressed in mgKOH per gram. The acid value threshold for this process is set in mgKOH per g. When the process control coefficient K is not lower than 0.8, the system automatically triggers a warning and control of process parameters, reducing the temperature of the corresponding process system by 10% to 15%, supplementing nitrogen to reduce the oxygen content of the system by more than 50%, until the real-time detected process control coefficient K does not exceed 0.5, ensuring that the degree of oil oxidation throughout the entire process is always within a controllable range.

[0037] This invention also constructs a precise shelf-life prediction model based on finished oil products. The model is built upon the Arrhenius oxidation kinetic equation and can accurately predict the shelf-life of finished products under normal temperature storage conditions. The specific formula is as follows: ; In the formula, The shelf life of the finished product is measured in months under normal temperature and light-protected conditions at 25°C. The peroxide value limit for the end of the shelf life of peanut oil is set at 0.15g per 100g. This is the initial peroxide value of the finished product, expressed in grams per 100g. The pre-exponential factor for the oxidation reaction is 2.17 × 10⁻⁶. 6 g per 100g per month; The activation energy for the oxidation of the finished oil is taken as 58.6 kJ per mol. The universal gas constant is 8.314 J per mol per K. The thermodynamic temperature for room temperature storage is 298.15K. The relative deviation between the shelf life predicted by this model and the actual shelf life measured in accelerated tests does not exceed 4.5%, providing accurate data support for product storage and shelf-life management.

[0038] The finished high-oleic peanut oil obtained by the method of this invention has an oleic acid content of not less than 75%, a linoleic acid content of not more than 8%, an initial peroxide value of not more than 0.05 g per 100 g, an initial acid value of not more than 0.1 mg KOH per g, no detectable aflatoxin B1, and a benzo[a]pyrene content of not more than 2 μg per kg. Under sealed conditions at room temperature (25°C) and protected from light, the product has a shelf life of not less than 24 months, with an end-of-shelf-life peroxide value of not more than 0.12 g per 100 g, an acid value of not more than 0.25 mg KOH per g, no rancid odor, no flavor deterioration, and an oleic acid retention rate of not less than 94%.

[0039] The present invention will be further described in detail below with reference to specific embodiments. The following embodiments are only used to illustrate the present invention and are not intended to limit the scope of protection of the present invention. Example 1

[0040] This embodiment provides a method for preparing high-oleic peanut oil with antioxidant properties, preservation, and extended shelf life. The specific implementation steps are as follows: S1 Raw Material Pretreatment Process High-oleic-acid peanut raw materials with an oleic acid content of 76.2% were selected. After shelling, impurity removal, and color sorting, moldy and broken particles were removed to obtain whole and uniform high-oleic-acid peanut kernels. The peanut kernels were then fed into a microwave device with a microwave frequency of 2450MHz and a power density of 0.8W per gram for low-temperature passivation treatment for 150 seconds, allowing the core temperature of the peanut kernels to rise uniformly to 55℃. After microwave passivation, the peanut kernels were immediately transferred to a closed-loop hot air drying device with a hot air temperature of 45℃ and an air velocity of 1.0m per second for gradient drying for 30 minutes, ultimately yielding pre-treated peanut kernels with a moisture content of 4.2% and a water activity of 0.42.

[0041] Testing showed that the lipoxygenase inactivation rate in this process was 98.7%, the endogenous γ-tocopherol retention rate was 93.2%, and the phytosterol retention rate was 91.5%, all of which met the process requirements.

[0042] S2 Low-Temperature Gradient Oxygen-Barrier Pressing Process The pretreated peanut kernels obtained from S1 were fed into a twin-screw press. Throughout the pressing process, food-grade nitrogen (99.99% purity) was used to maintain a slight positive pressure of 0.02 MPa within the pressing chamber. A three-stage gradient pressure-temperature controlled pressing process was employed: the first stage was set at a pressing temperature of 35℃, a pressing pressure of 8 MPa, and a material residence time of 20 seconds; the second stage was set at a pressing temperature of 40℃, a pressing pressure of 18 MPa, and a material residence time of 30 seconds; the third stage was set at a pressing temperature of 45℃, a pressing pressure of 25 MPa, and a material residence time of 40 seconds. After pressing, the kernels were filtered through a screen to remove cake and debris, yielding high-oleic peanut oil.

[0043] Tests showed that the oleic acid retention rate in this process was 96.8%, the residual oil rate in the cake meal was 6.2%, and the initial peroxide value of the crude oil was 0.021g per 100g, which met the process requirements.

[0044] S3 Colloid-Assisted Low-Temperature Degumming Process The high-oleic peanut oil obtained from S2 was placed in a closed, oxygen-free reaction system under nitrogen protection throughout the process. The oil was heated to 38°C, and 0.15% (by weight) of a composite colloid degumming agent was added. The composite colloid degumming agent was composed of soybean lecithin, chitosan oligosaccharide, and trisodium citrate in a mass ratio of 2:1:1. The stirring speed was set to 120 rpm, and the reaction was carried out at a constant temperature for 35 minutes. After the reaction was completed, the material was transferred to a closed centrifuge and centrifuged at 4500 rpm for 15 minutes. The supernatant was collected to obtain the degummed clear oil.

[0045] Tests showed that the phospholipid content in the degummed oil was 26 mg per kg, the hydration degumming rate was 99.2%, and the free iron ion content in the oil was 0.08 mg per kg, which met the process requirements.

[0046] S4 in-situ chelation antioxidant process The degummed oil obtained from S3 was placed in a sealed reactor protected from light and under nitrogen atmosphere throughout the process. Nitrogen was continuously introduced to maintain an oxygen content of 0.25% in the reactor. The degummed oil was heated to 42°C, and 0.08% (by weight) of a composite natural antioxidant system was added. The composite natural antioxidant system was composed of rosemary extract, tea polyphenol palmitate, γ-tocopherol, and sodium phytate in a mass ratio of 3:2:1:1. The rosemary extract contained 62% oxalic acid. The stirring speed was set to 80 rpm, and the reaction was carried out at a constant temperature for 60 minutes to obtain an antioxidant pretreated oil.

[0047] Testing showed that the synergistic antioxidant enhancement coefficient of the composite system used in this process was 2.1, and the oxidation induction period of the treated oil at 120℃ was 29.5h, which meets the process requirements.

[0048] S5 Low-Temperature Light-Proofing Co-Curing Process The antioxidant pretreated oil obtained from S4 was placed in a sealed maturation tank, and the maturation temperature was set at 10°C. Nitrogen gas was continuously introduced to maintain the oxygen content of the system at 0.25%. The mixture was allowed to stand and mature in the dark for 72 hours without any heating or stirring. After maturation, a 0.22μm sterile filter membrane was used for negative pressure filtration under slightly positive nitrogen pressure to obtain refined high-oleic peanut oil.

[0049] Tests showed that the wax content in the cured oil was 4.2 mg per kg, and the solid fat content was 0.018% after being placed at 0℃ for 5.5 hours, which met the process requirements.

[0050] S6 Aseptic and Anaerobic Filling Process The refined high-oleic peanut oil obtained from S5 was sent to a Class 100 clean, light-proof, low-temperature sealed filling room for anaerobic filling, with the filling environment temperature set at 8℃. Before filling, the food-grade packaging containers were subjected to three vacuum-nitrogen-filling cycles to replace headspace oxygen using food-grade nitrogen with 99.99% purity. After replacement, the residual oxygen content in the headspace of the container was 0.18%. After filling, the containers were immediately sealed under a nitrogen atmosphere. The residual oxygen content in the headspace of the finished packaging was 0.12%, and the sealing leakage rate was 0.008%, finally yielding the finished high-oleic peanut oil.

[0051] In this embodiment, the cumulative contact time between oil and oxygen in the entire preparation process accounts for 10.2%, and the highest ambient temperature of material contact throughout the process is 45℃. Testing revealed that the finished product contains 75.8% oleic acid, 7.6% linoleic acid, an initial peroxide value of 0.042 g / 100g, an initial acid value of 0.08 mg KOH / g, no aflatoxin B1 detected, and benzo[a]pyrene content of 1.2 μg / kg. Accelerated oxidation testing verified that under sealed conditions at 25℃ in the dark, the product has a shelf life of 26 months, with an end-of-shelf peroxide value of 0.11 g / 100g, an acid value of 0.22 mg KOH / g, no rancid odor, no flavor deterioration, and an oleic acid retention rate of 94.5%. Example 2

[0052] This embodiment provides a method for preparing high-oleic peanut oil with antioxidant properties, preservation, and extended shelf life. The specific implementation steps are as follows: S1 Raw Material Pretreatment Process High-oleic-acid peanut raw materials with an oleic acid content of 77.5% were selected. After shelling, impurity removal, and color sorting, moldy and broken particles were removed to obtain whole and uniform high-oleic-acid peanut kernels. The peanut kernels were then fed into a microwave device with a microwave frequency of 2450MHz and a power density of 1.0W per gram for low-temperature passivation treatment for 120 seconds, allowing the core temperature of the peanut kernels to rise uniformly to 58℃. After microwave passivation, the peanut kernels were immediately transferred to a closed-loop hot air drying device with a hot air temperature of 48℃ and an air velocity of 1.2m per second for gradient drying for 25 minutes, finally obtaining pretreated peanut kernels with a moisture content of 4.0% and a water activity of 0.40.

[0053] Testing showed that the lipoxygenase inactivation rate in this process was 99.2%, the endogenous γ-tocopherol retention rate was 93.8%, and the phytosterol retention rate was 92.1%, all of which met the process requirements.

[0054] S2 Low-Temperature Gradient Oxygen-Barrier Pressing Process The pretreated peanut kernels obtained from S1 were fed into a twin-screw press. Throughout the pressing process, food-grade nitrogen with a purity of 99.99% was used to maintain a slight positive pressure of 0.03 MPa within the pressing chamber. A three-stage gradient pressure-temperature controlled pressing process was employed. The first stage was set at a pressing temperature of 38℃, a pressing pressure of 10 MPa, and a material residence time of 18 seconds. The second stage was set at a pressing temperature of 42℃, a pressing pressure of 20 MPa, and a material residence time of 28 seconds. The third stage was set at a pressing temperature of 48℃, a pressing pressure of 28 MPa, and a material residence time of 38 seconds. After pressing, the peanut oil was filtered through a screen to remove cake and debris, yielding high-oleic peanut oil.

[0055] Tests showed that the oleic acid retention rate in this process was 97.2%, the residual oil rate in the cake meal was 5.8%, and the initial peroxide value of the crude oil was 0.018g per 100g, which met the process requirements.

[0056] S3 Colloid-Assisted Low-Temperature Degumming Process The high-oleic peanut oil obtained from S2 was placed in a closed, oxygen-free reaction system under nitrogen protection throughout the process. The oil was heated to 40°C, and 0.22% (by weight) of a composite colloid degumming agent was added. The composite colloid degumming agent was composed of soybean lecithin, chitosan oligosaccharide, and trisodium citrate in a mass ratio of 2:1:1. The stirring speed was set to 150 rpm, and the reaction was carried out at a constant temperature for 30 minutes. After the reaction was completed, the material was transferred to a closed centrifuge and centrifuged at 5000 rpm for 12 minutes. The supernatant was collected to obtain the degummed clear oil.

[0057] Tests showed that the phospholipid content in the degummed oil was 22 mg per kg, the hydration degumming rate was 99.4%, and the free iron ion content in the oil was 0.06 mg per kg, which met the process requirements.

[0058] S4 in-situ chelation antioxidant process The degummed oil obtained from S3 was placed in a sealed reactor protected from light and under nitrogen atmosphere throughout the process. Nitrogen was continuously introduced to maintain an oxygen content of 0.2% in the reactor. The degummed oil was heated to 45°C, and 0.15% (by weight) of a composite natural antioxidant system was added. The composite natural antioxidant system was composed of rosemary extract, tea polyphenol palmitate, γ-tocopherol, and sodium phytate in a mass ratio of 3:2:1:1. The rosemary extract contained 65% carrageenan. The stirring speed was set to 100 rpm, and the reaction was carried out at a constant temperature for 50 minutes to obtain an antioxidant pretreated oil.

[0059] Testing showed that the composite system used in this process had a synergistic antioxidant enhancement coefficient of 2.4, and the oxidation induction period of the treated oil at 120℃ was 32 hours, which meets the process requirements.

[0060] S5 Low-Temperature Light-Proofing Co-Curing Process The antioxidant pretreated oil obtained from S4 was placed in a sealed maturation tank, and the maturation temperature was set at 12°C. Nitrogen gas was continuously introduced to maintain the oxygen content of the system at 0.2%. The mixture was allowed to stand and mature in the dark for 60 hours without any heating or stirring during the maturation process. After maturation, a 0.22μm sterile filter membrane was used for negative pressure filtration under a slightly positive nitrogen pressure to obtain refined high-oleic peanut oil.

[0061] Tests showed that the wax content in the cured oil was 3.5 mg per kg, and the solid fat content was 0.015% after being placed at 0℃ for 5.5 hours, which met the process requirements.

[0062] S6 Aseptic and Anaerobic Filling Process The refined high-oleic peanut oil obtained from S5 was sent to a Class 100 clean, light-proof, low-temperature sealed filling room for anaerobic filling, with the filling environment temperature set at 10℃. Before filling, the food-grade packaging containers were subjected to four vacuum-nitrogen-filling cycles to replace headspace oxygen using food-grade nitrogen with 99.99% purity. After replacement, the residual oxygen content in the headspace of the container was 0.15%. After filling, the containers were immediately sealed under a nitrogen atmosphere. The residual oxygen content in the headspace of the finished product packaging was 0.1%, and the sealing leakage rate was 0.005%, ultimately yielding the finished high-oleic peanut oil.

[0063] In this embodiment, the cumulative contact time between the oil and oxygen in the entire preparation process accounted for 8.7%, and the highest ambient temperature of material contact throughout the process was 48℃. Testing revealed that the finished product contained 76.9% oleic acid, 7.2% linoleic acid, an initial peroxide value of 0.035g per 100g, an initial acid value of 0.06mgKOH perg, no aflatoxin B1 detected, and benzo[a]pyrene content of 1.0μg / kg. Accelerated oxidation testing verified that under sealed conditions at 25℃ in the dark, the product had a shelf life of 28 months, with an end-of-shelf-life peroxide value of 0.10g per 100g, an acid value of 0.20mgKOH perg, no rancid odor, no flavor deterioration, and an oleic acid retention rate of 95.2%. Example 3

[0064] This embodiment provides a method for preparing high-oleic peanut oil with antioxidant properties, preservation, and extended shelf life. The specific implementation steps are as follows: S1 Raw Material Pretreatment Process High-oleic-acid peanut raw materials with an oleic acid content of 78.1% were selected. After shelling, impurity removal, and color sorting, moldy and broken particles were removed to obtain whole and uniform high-oleic-acid peanut kernels. The peanut kernels were then fed into a microwave device with a microwave frequency of 2450MHz and a power density of 1.2W per gram for low-temperature passivation treatment for 90 seconds, allowing the core temperature of the peanut kernels to rise uniformly to 60℃. After microwave passivation, the peanut kernels were immediately transferred to a closed-loop hot air drying device with a hot air temperature of 50℃ and an air velocity of 1.5m per second for gradient drying for 20 minutes, finally obtaining pretreated peanut kernels with a moisture content of 3.6% and a water activity of 0.38.

[0065] Testing showed that the lipoxygenase inactivation rate in this process was 99.0%, the endogenous γ-tocopherol retention rate was 92.5%, and the phytosterol retention rate was 90.8%, all of which met the process requirements.

[0066] S2 Low-Temperature Gradient Oxygen-Barrier Pressing Process The pretreated peanut kernels obtained from S1 were fed into a twin-screw press. Throughout the pressing process, food-grade nitrogen (99.99% purity) was used to maintain a slight positive pressure of 0.05 MPa within the pressing chamber. A three-stage gradient pressure-temperature controlled pressing process was employed: the first stage was set at a pressing temperature of 40℃, a pressing pressure of 12 MPa, and a material residence time of 15 seconds; the second stage was set at a pressing temperature of 45℃, a pressing pressure of 22 MPa, and a material residence time of 25 seconds; the third stage was set at a pressing temperature of 50℃, a pressing pressure of 30 MPa, and a material residence time of 35 seconds. After pressing, the kernels were filtered through a screen to remove cake and debris, yielding high-oleic peanut oil.

[0067] Tests showed that the oleic acid retention rate in this process was 96.6%, the residual oil rate in the cake meal was 5.5%, and the initial peroxide value of the crude oil was 0.024g per 100g, which met the process requirements.

[0068] S3 Colloid-Assisted Low-Temperature Degumming Process The high-oleic peanut oil obtained from S2 was placed in a closed, oxygen-free reaction system under nitrogen protection throughout the process. The oil was heated to 42°C, and 0.3% (by weight) of a composite colloid degumming agent was added. This composite degumming agent was composed of soybean lecithin, chitosan oligosaccharide, and trisodium citrate in a mass ratio of 2:1:1. The stirring speed was set to 180 rpm, and the reaction was carried out at a constant temperature for 25 minutes. After the reaction was completed, the material was transferred to a closed centrifuge and centrifuged at 5500 rpm for 10 minutes. The supernatant was collected to obtain the degummed clear oil.

[0069] Tests showed that the phospholipid content in the degummed oil was 18 mg per kg, the hydration degumming rate was 99.5%, and the free iron ion content in the oil was 0.05 mg per kg, which met the process requirements.

[0070] S4 in-situ chelation antioxidant process The degummed oil obtained from S3 was placed in a sealed reactor protected from light and under nitrogen atmosphere throughout the process. Nitrogen was continuously introduced to maintain the oxygen content in the reactor at 0.18%. The degummed oil was heated to 48°C, and 0.25% (by weight) of a composite natural antioxidant system was added. The composite natural antioxidant system was composed of rosemary extract, tea polyphenol palmitate, γ-tocopherol, and sodium phytate in a mass ratio of 3:2:1:1. The rosemary extract contained 60% carrageenan. The stirring speed was set to 120 rpm, and the reaction was carried out at a constant temperature for 40 minutes to obtain an antioxidant pretreated oil.

[0071] Testing showed that the composite system used in this process had a synergistic antioxidant enhancement coefficient of 2.2, and the oxidation induction period of the treated oil at 120℃ was 30.5h, which meets the process requirements.

[0072] S5 Low-Temperature Light-Proofing Co-Curing Process The antioxidant pretreated oil obtained from S4 was placed in a sealed maturation tank, and the maturation temperature was set at 14°C. Nitrogen gas was continuously introduced to maintain the oxygen content of the system at 0.18%. The mixture was allowed to stand and mature in the dark for 48 hours without any heating or stirring. After maturation, a 0.22μm sterile-grade filter membrane was used for negative pressure filtration under a slightly positive nitrogen pressure to obtain refined high-oleic peanut oil.

[0073] Tests showed that the wax content in the cured oil was 3.8 mg per kg, and the solid fat content was 0.016% after being placed at 0℃ for 5.5 hours, which met the process requirements.

[0074] S6 Aseptic and Anaerobic Filling Process The refined high-oleic peanut oil obtained from S5 was sent to a Class 100 clean, light-proof, low-temperature sealed filling room for anaerobic filling, with the filling environment temperature set at 12℃. Before filling, the headspace oxygen in the food-grade packaging containers was replaced five times using food-grade nitrogen gas with a purity of 99.99%, resulting in a headspace residual oxygen content of 0.12% after replacement. After filling, the containers were immediately sealed under a nitrogen atmosphere, with a headspace residual oxygen content of 0.08% and a sealing leakage rate of 0.003%, ultimately yielding the finished high-oleic peanut oil.

[0075] In this embodiment, the cumulative contact time between the oil and oxygen in the entire preparation process accounts for 9.5%, and the highest ambient temperature of material contact throughout the process is 50°C. Testing revealed that the finished product contains 77.4% oleic acid, 6.8% linoleic acid, an initial peroxide value of 0.038 g / 100g, an initial acid value of 0.07 mg KOH / g, no aflatoxin B1 detected, and benzo[a]pyrene content of 1.1 μg / kg. Accelerated oxidation testing verified that under sealed conditions at 25°C in the dark, the product has a shelf life of 27 months, with an end-of-shelf peroxide value of 0.105 g / 100g, an acid value of 0.21 mg KOH / g, no rancid odor, no flavor deterioration, and an oleic acid retention rate of 94.8%.

[0076] This invention employs a low-temperature, oxygen-free process design throughout the entire process, combined with a microwave-hot air dual-stage passivation process. This achieves highly efficient passivation of endogenous pro-oxidative enzymes such as lipoxygenase and phospholipase during the raw material processing stage, while avoiding the destruction of natural antioxidant active components in peanuts caused by traditional high-temperature processing. It effectively preserves endogenous active substances such as γ-tocopherol and phytosterols. Strict control over the contact time between oil and oxygen and the ambient temperature of the materials throughout the process inhibits the initiation of the oil oxidation chain reaction from the source of processing, reducing the initial oxidation level of crude peanut oil and laying a stable foundation for subsequent long-term antioxidant treatment.

[0077] This invention employs a process combining colloid-based synergistic low-temperature degumming with in-situ chelation antioxidants. By using a compounded colloidal degumming agent, it simultaneously removes phospholipids, free metal ions, and other pro-oxidation precursors from crude oil, reducing catalytic factors for oil oxidation during storage. The compounded natural antioxidant system achieves synergistic antioxidant effects from multiple components. In-situ chelation reaction ensures stable dispersion and anchoring of antioxidant active ingredients in the oil phase, extending the oxidation induction period of the oil and constructing an endogenous, long-lasting antioxidant protection system. This solves the limitations of single antioxidants and the quality control problems associated with the use of synthetic antioxidants.

[0078] This invention utilizes a low-temperature, light-protected synergistic ripening process and aseptic, oxygen-free filling to further remove trace amounts of wax and solid impurities from the oil, reducing the risk of oxidation during finished product storage. The accompanying real-time monitoring and feedback control algorithm for the entire oxidation process enables dynamic control of oil quality during processing, ensuring consistent and stable product quality across different batches. A shelf-life prediction model based on Arrhenius oxidation kinetics allows for accurate prediction of the finished product's shelf life. The resulting high-oleic peanut oil exhibits a significantly extended shelf life under sealed, light-protected conditions at room temperature, maintaining stable physicochemical indicators and flavor quality throughout the storage period, meeting relevant national food safety standards.

[0079] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing high-oleic peanut oil with antioxidant properties, preservation properties, and extended shelf life, characterized in that, Includes the following steps: S1. Raw material pretreatment process: Microwave-hot air dual-stage passivation process is adopted to perform targeted enzyme activation passivation and gradient drying on the shelled and graded high oleic peanut kernels. This process targets and passivates endogenous prooxidant enzymes such as lipoxygenase and phospholipase in peanut kernels, while retaining the natural antioxidant active ingredients such as γ-tocopherol and phytosterols in peanuts to the greatest extent, thus obtaining pretreated peanut kernels. S2, Low-temperature gradient oxygen-free pressing process: The pretreated peanut kernels obtained in S1 are sent into a twin-screw press with full nitrogen micro-positive pressure oxygen-free protection. The three-stage gradient pressure increase and temperature control pressing process is adopted to complete the oil pressing and extraction in a low-temperature oxygen-free environment, inhibiting the oxidative degradation of oleic acid and the initiation of free radical chain reaction during the pressing process, and obtaining high oleic acid peanut crude oil. S3, Colloidal Synergistic Low-Temperature Degumming Process: The high-oleic peanut oil obtained in S2 is placed in a closed oxygen-free reaction system, and a composite colloidal degumming agent is used for low-temperature hydration synergistic chelation degumming treatment to remove colloidal impurities, free metal ions and oxidation precursors from the crude oil. After centrifugation, degummed clear oil is obtained. S4, In-situ Chelation Antioxidant Process: The degummed oil obtained in S3 is placed in a sealed reaction vessel protected from light and nitrogen throughout the process. A composite natural antioxidant system, which combines natural antioxidant components and metal ion chelating agents, is added. Under low temperature and constant temperature conditions, the in-situ chelation reaction and the anchoring of the antioxidant active groups in the oil phase are completed, and an endogenous long-term antioxidant protection system for the oil is constructed to obtain an antioxidant pretreated oil. S5. Low-temperature and light-protected synergistic ripening process: The antioxidant pretreated oil obtained in S4 is placed in a closed environment with low temperature, light protection and nitrogen protection throughout the process for constant temperature static ripening treatment to remove trace wax, colloidal precipitates and volatile odor substances from the oil. After ripening, it is filtered through sterilization-grade precision to obtain refined high oleic acid peanut oil. S6. Aseptic and oxygen-free filling process: The refined high oleic peanut oil obtained from S5 is filled and sealed in a Class 100 clean, low-temperature, light-proof, and airtight environment with nitrogen replacement to minimize the residual oxygen content in the finished product packaging and block the oxidation reaction path during storage. The cumulative contact time between oil and oxygen in the entire preparation process is ≤12%, and the highest ambient temperature of materials in contact throughout the process is ≤65℃.

2. The method for preparing high-oleic peanut oil with antioxidant properties and extended shelf life according to claim 1, characterized in that, The specific steps of the microwave-hot air dual-stage passivation process in step S1 are as follows: First, the shelled and graded high-oleic peanut kernels are placed in a microwave device with a microwave frequency of 2450MHz and a power density of 0.8-1.2W / g, and subjected to low-temperature passivation treatment for 90-150s, so that the core temperature of the peanut kernels rises uniformly to 55-60℃; then, the microwave-passivated peanut kernels are immediately placed in a closed-loop hot air drying device with a hot air temperature of 45-50℃ and a wind speed of 1.0-1.5m / s, and subjected to gradient drying for 20-30min to obtain pretreated peanut kernels with a moisture content of 3.5%-4.5% and a water activity ≤0.45; the passivation rate of lipoxygenase in step S1 must meet the following calculation formula: ； In the formula, The inactivation rate of lipoxygenase is expressed as % . The enzyme activity of lipoxygenase in peanut kernels after passivation treatment is expressed in U / g. The initial enzyme activity of lipoxygenase in untreated peanut kernels is expressed in U / g; and the process in step S1 must meet the following requirements. The retention rate of endogenous γ-tocopherol is ≥92%, and the retention rate of phytosterols is ≥90%.

3. The method for preparing high-oleic peanut oil with antioxidant properties and extended shelf life according to claim 1, characterized in that, The three-stage gradient pressure-controlled pressing process in step S2 involves filling the entire process with food-grade nitrogen gas with a purity ≥99.99% to maintain a slight positive pressure of 0.02-0.05 MPa within the pressing chamber. The specific parameters for the three stages are as follows: First stage pressing temperature 35-40℃, pressing pressure 8-12 MPa, material residence time 15-20 s, completing the initial cell wall disruption and pre-extraction of peanut kernels; Second stage pressing temperature 40-45℃, pressing pressure 18-22 MPa, material residence time 25-30 s, completing the gentle extraction of the main oil; Third stage pressing temperature 45-50℃, pressing pressure 25-30 MPa, material residence time 35-40 s, completing the deep extraction of residual oil. The oleic acid retention rate in step S2 must meet the following kinetic calculation formula: ； In the formula, Oleic acid retention rate, in percentages (%) The pre-exponential factor for the oleic acid oxidation reaction is 3.2 × 10⁻⁶. 5 min -1 ; Total pressing time, in minutes; The activation energy for the oxidation of oleic acid is 42.3 kJ / mol. This is the universal gas constant, with a value of 8.314 J / (mol·K); The temperature of the pressing system is expressed in Kelvin (K). Furthermore, the process of step S2 must meet the following requirements. The residual oil content of the oil cake is ≤6.5%, and the initial peroxide value of the crude oil is ≤0.03g / 100g.

4. The method for preparing high-oleic peanut oil with antioxidant properties and extended shelf life according to claim 1, characterized in that, The colloidal synergistic low-temperature degumming process in step S3 is as follows: the high-oleic peanut crude oil obtained in S2 is heated to 38-42℃, and 0.15%-0.3% of the crude oil mass of a composite colloidal degumming agent is added under nitrogen protection. The mixture is stirred at a constant temperature at 120-180 r / min for 25-35 min to allow the composite colloidal degumming agent to fully chelate and flocculate with the phospholipids and free metal ions in the crude oil. Then, the mixture is centrifuged in a closed system at 4500-5500 r / min for 10-15 min, and the clear oil in the upper layer is taken to obtain degummed oil. The composite colloidal degumming agent is composed of soybean lecithin, chitosan oligosaccharide and trisodium citrate in a mass ratio of 2:1:

1. After degumming, the phospholipid content in the oil is ≤30mg / kg, the hydration degumming rate is ≥99%, and the free iron ion content in the oil is ≤0.1mg / kg.

5. The method for preparing high-oleic peanut oil with antioxidant properties and extended shelf life according to claim 1, characterized in that, The in-situ chelation antioxidant process in step S4 is specifically as follows: the degummed oil obtained in S3 is placed in a sealed reactor protected from light and nitrogen throughout the process, maintaining the oxygen content in the reactor at ≤0.3%, and the temperature is raised to 42-48℃. A composite natural antioxidant system at 0.08%-0.25% of the degummed oil mass is added, and the mixture is stirred at a constant temperature of 80-120 r / min for 40-60 min to complete the in-situ chelation of metal ions and the stable dispersion and anchoring of the antioxidant active groups in the oil phase, resulting in an antioxidant pretreated oil. The composite natural antioxidant system is composed of rosemary extract (with oxalic acid content ≥60%), tea polyphenol palmitate, γ-tocopherol, and sodium phytate in a mass ratio of 3:2:1:

1. The synergistic antioxidant enhancement coefficient of the composite system must meet the following calculation formula: ； In the formula, The synergistic antioxidant enhancement coefficient; , , , The figures represent the DPPH half-maximal inhibitory concentrations (IC50) of rosemary extract, tea polyphenol palmitate, γ-tocopherol, and sodium phytate when used alone, in mg / L. The DPPH radical scavenging half-maximal inhibitory concentration (IC50) is the concentration of free radicals inhibited when the composite system is used in combination, expressed in mg / L; and the composite system must meet the following requirements. The oxidation induction period of oils at 120℃ is ≥28h.

6. The method for preparing high-oleic peanut oil with antioxidant properties and extended shelf life according to claim 1, characterized in that, The low-temperature light-protected synergistic ripening process in step S5 is as follows: the antioxidant pretreated oil obtained in S4 is placed in a sealed ripening tank at a temperature of 10-14℃, protected from light throughout the process, and under nitrogen protection. The oxygen content of the system is maintained at ≤0.3%, and the oil is allowed to ripen for 48-72 hours. No heating or stirring is performed during the ripening process. After ripening, a 0.22μm sterile filter membrane is used for negative pressure filtration under a slight positive pressure of nitrogen to remove trace amounts of wax, colloids, and solid impurities precipitated from the oil, resulting in refined high-oleic peanut oil. The wax content in the oil after ripening is ≤5mg / kg, and the solid fat content at 0℃ for 5.5 hours is ≤0.02%.

7. The method for preparing high-oleic peanut oil with antioxidant properties and extended shelf life according to claim 1, characterized in that, The aseptic and anaerobic filling process in step S6 is as follows: The refined high oleic peanut oil obtained in S5 is filled anaerobically in a closed filling room with a Class 100 cleanroom, protected from light, and at a low temperature of 8-12℃. Before filling, the food-grade packaging container is vacuumed and purged with nitrogen gas with a purity of ≥99.99% for more than 3 times to replace the headspace oxygen. After replacement, the residual oxygen content in the headspace of the container is ≤0.2%. After filling, the container is immediately sealed in a nitrogen atmosphere. The residual oxygen content in the headspace of the finished product packaging is ≤0.15%, and the sealing leakage rate is ≤0.01%.

8. The method for preparing high-oleic peanut oil with antioxidant preservation and extended shelf life according to any one of claims 1 to 7, characterized in that, The preparation method also includes a real-time monitoring and feedback control algorithm for the oxidation degree of all processes from S1 to S6. The algorithm uses peroxide value (POV) and acid value (AV) as core monitoring indicators, sets online detection nodes at the discharge port of each process, and calculates the process control coefficient using the following formula to adjust the temperature, oxygen content, and reaction time of each process in real time: ； In the formula, This is the process control coefficient; This refers to the peroxide value measured in real time for the corresponding process, expressed in g / 100g. A threshold value for peroxide value is set for this process, in g / 100g. The acid value is measured in real time for the corresponding process, and the unit is mgKOH / g; A threshold value is set for the acid value in this process, in mgKOH / g; when When this occurs, a process parameter early warning and control mechanism is triggered, reducing the temperature of the corresponding process system by 10%-15%, supplementing nitrogen to reduce the oxygen content of the system by more than 50%, until the real-time detection... .

9. The method for preparing high-oleic peanut oil with antioxidant preservation and extended shelf life according to any one of claims 1 to 7, characterized in that, The preparation method also includes a precise shelf-life prediction model based on the finished product obtained in steps S1 to S6. This model is constructed based on the Arrhenius oxidation kinetic equation, and the specific formula is as follows: ； In the formula, The shelf life of the finished product is measured in months under normal temperature and light-protected conditions at 25°C. The peroxide value limit for the end of the shelf life of peanut oil is set at 0.15g / 100g. This is the initial peroxide value of the finished product, expressed in g / 100g. The pre-exponential factor for the oxidation reaction is 2.17 × 10⁻⁶. 6 g / (100g·month); The activation energy for the oxidation of the finished oil is taken as 58.6 kJ / mol; This is the universal gas constant, with a value of 8.314 J / (mol·K); The thermodynamic temperature for room temperature storage is 298.15K; the relative deviation between the shelf life predicted by the model and the actual shelf life measured by accelerated testing is ≤4.5%.

10. The method for preparing high-oleic peanut oil with antioxidant preservation and extended shelf life according to any one of claims 1 to 7, characterized in that, The finished high-oleic peanut oil obtained through steps S1 to S6 has an oleic acid content ≥75%, a linoleic acid content ≤8%, an initial peroxide value ≤0.05g / 100g, an initial acid value ≤0.1mgKOH / g, no detectable aflatoxin B1, and a benzo[a]pyrene content ≤2μg / kg. Under sealed conditions at room temperature (25℃) protected from light, it has a shelf life ≥24 months, an end-of-shelf-life peroxide value ≤0.12g / 100g, an acid value ≤0.25mgKOH / g, no rancid odor, no flavor deterioration, and an oleic acid retention rate ≥94%.

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