Pork-vegetable oil blend and process for its preparation

Abstract

The application provides a lard-vegetable oil blend oil and a preparation process thereof, and belongs to the technical field of edible oil processing. The preparation process comprises the following steps: lard fractionation, vegetable oil base preparation, low-melting-point component fusion with the vegetable oil base, high-melting-point component crystallization induction, and temperature reduction and shaping. The preparation process is based on low-temperature fractionation to first fractionate lard, to obtain high-melting-point components containing saturated triglycerides and low-melting-point components containing unsaturated triglycerides, then first fuse the low-melting-point components with the vegetable oil base at high temperature to form an oil system, then low-temperature freeze and crush the high-melting-point components into micropowder as natural heterogeneous crystal nuclei to induce the oil system to generate fine and uniform beta' stable crystal forms, and finally obtain the finished product through temperature reduction, crystal growth and shaping. The process relies on the components of lard itself to realize physical self-stability of the system, does not need to add emulsifiers and other exogenous aids, and can effectively solve the problems of easy separation at low temperature and easy stratification at high temperature of traditional blend oils.

Description

Technical Field

[0001] This invention belongs to the field of edible oil processing technology, specifically relating to a lard-vegetable oil blend and its preparation process. Background Technology

[0002] The ratio of saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids is close to 1:1:1, and the ratio of linoleic acid to linolenic acid is controlled at 4. A 6:1 ratio is the ideal fatty acid ratio for edible oils. Lard, as a traditional high-quality animal fat, is rich in saturated fatty acids and characteristic flavor compounds, but its high saturated fatty acid content when consumed alone is a problem. Vegetable oils are rich in unsaturated fatty acids, but generally lack adequate amounts of saturated fatty acids and the unique flavor components of animal fats.

[0003] Existing technologies have disclosed various blending schemes for animal and vegetable oils. For example, Chinese patent CN1491566A discloses a high-quality medicinal and edible oil made from compound animal and vegetable fats and its manufacturing method. It mainly uses animal and vegetable fats as raw materials to balance saturated fatty acids, unsaturated fatty acids, and cholesterol. It uses compound vitamins to increase nutrition and provide antioxidant and photodegradation protection. It uses compound colorants to resist the discoloration of refined oils and only uses a simple stirring and mixing process. Chinese patent CN104186710A discloses a blended oil of all fatty acids with an ideal composition ratio, which is prepared by heating and melting lard, tallow, and vegetable oil and then directly mixing them. Chinese patent CN110432339A discloses a lipid-lowering edible blended oil, which is prepared by melting and cooling lard separately and then simply mixing it with other oil raw materials.

[0004] These existing technologies generally suffer from the following drawbacks in the preparation process: 1. The triglycerides with different melting points in the lard were not graded and separated. The high-melting-point triglycerides were mixed with the low-melting-point vegetable oil in a disorderly manner. When stored at low temperature, they are prone to forming coarse crystals, causing the oil to separate, become cloudy, and precipitate, resulting in poor shelf-life stability. 2. The system cannot form a self-stabilizing structure and can only rely on external emulsifiers, thickeners, structural lipids, etc. to maintain a uniform state, which does not conform to the market development trend of food clean labels and no exogenous additives; 3. The process often involves a single high-temperature blending process, which makes the heat-sensitive flavor compounds in lard or vegetable oils easily volatilized and oxidized, resulting in a thin flavor and low reduction in the finished product. 4. Relying solely on the crude ratio of raw materials makes it impossible to precisely control the ratio of the three types of fatty acids and linoleic acid / linolenic acid, making it difficult to consistently achieve the golden ratio recommended by the World Health Organization; 5. The process is crude, lacking oxygen control, light protection, and airtight protection designs, making polyunsaturated fatty acids prone to oxidation and rancidity, thus limiting the product's shelf life.

[0005] To address the shortcomings of existing processes, such as poor low-temperature stability, reliance on exogenous additives, significant flavor loss, and uncontrollable fatty acid ratios, there is an urgent need to improve existing technologies and develop a new process for preparing lard-vegetable blended oil that features precise ratios, good storage stability, high flavor retention, and suitability for large-scale production. Summary of the Invention

[0006] To address the aforementioned issues, this invention separates lard into functional components with different melting points through low-temperature fractionation. This is combined with a blend of vegetable oils, pre-fusion of low-melting-point components, and freeze-drying of high-melting-point components to induce crystallization. This, along with a cooling crystal growth process, achieves physical stability of the oil system without the addition of emulsifiers or thickeners. The fatty acid ratio can be precisely controlled to a standard golden ratio, significantly preserving the intrinsic flavor of lard. Furthermore, the process parameters are controllable and highly replicable, making it suitable for continuous industrial production. This addresses industry pain points such as low-temperature precipitation, high-temperature stratification, flavor loss, inaccurate proportions, and reliance on additives in traditional blended oils.

[0007] In a first aspect, the present invention provides a process for preparing a lard-vegetable oil blend, comprising the following steps: S1 Lard Extraction: Lard is heated and melted, then cooled and crystallized to obtain a high-melting-point component A and a low-melting-point component B; the high-melting-point component A includes saturated triglycerides, and the low-melting-point component B includes unsaturated triglycerides. S2 Vegetable Oil Base Material Preparation: Select at least one vegetable oil and mix them to obtain a vegetable oil base; S3 low-melting-point component blended with vegetable oil base: Heating causes the low-melting-point component B obtained in step S1 and the vegetable oil base obtained in step S2 to be fused together to obtain a liquid mixture; S4 high-melting-point component induces crystallization: The high-melting-point component A obtained in step S1 is cryogenically pulverized into powder and added to the liquid mixture obtained in step S3 to induce the formation of β'-type microcrystals, thus forming an oil system. S5 Cooling and Shaping: The oil system obtained in step S4 is cooled to crystallize, and then kept at a constant temperature to grow crystals. After standing and stabilizing, the lard-vegetable oil blended product is obtained.

[0008] The proposed method first involves cooling and crystallizing molten lard to separate high-melting-point component A and low-melting-point component B. Vegetable oil is then premixed and compounded to form a vegetable oil base. Next, low-melting-point component A is fused with the vegetable oil base at high temperature to form an oil system. The high-melting-point component is then cryogenically pulverized into microparticles as natural heterogeneous crystal nuclei, inducing the formation of β'-type microcrystals in the oil system. Finally, after cooling and crystal formation, blended oil is obtained. The blended oil exhibits a β'-type crystal structure, resulting in a fine and stable composition, effectively solving the problems of easy precipitation at low temperatures and easy stratification at high temperatures in traditional blended oils.

[0009] Preferably, the lard-vegetable oil blending process does not add any exogenous additives, including emulsifiers, and relies solely on the components of lard itself to achieve physical self-stability of the system.

[0010] Preferably, in step S1, the heated and melted lard is cooled to 20-30°C to crystallize, so as to ensure that the content of saturated triglycerides and unsaturated triglycerides in component A and component B is appropriate, which is conducive to subsequent fusion and crystallization.

[0011] More preferably, the lard is heated to 50-60°C to melt, so as to ensure that the lard is fully melted and the composition is uniform.

[0012] More preferably, the temperature is lowered to 20-30℃ at a rate of 1-3℃ / h to induce crystallization.

[0013] More preferably, after cooling to 20-30℃, the crystals are grown in a constant-temperature, sealed environment for 12-24 hours.

[0014] Low-temperature slow crystallization separation allows high-melting-point triglycerides to crystallize out in an orderly manner, which is beneficial for the stability of the subsequent system.

[0015] Preferably, the high-melting-point component A has a melting point of 38–48°C; and the low-melting-point component B has a melting point <28°C. More preferably, the high-melting-point component A has a melting point of 38–46°C; and the low-melting-point component B has a melting point <25°C.

[0016] Preferably, in step S1, separation is performed using plate and frame filtration or centrifugal separation.

[0017] Preferably, step S1 is carried out under the protection of a closed inert gas (such as nitrogen) in order to preserve the characteristic flavor substances of lard to the maximum extent.

[0018] Preferably, in step S2, the mixing temperature of the vegetable oil is 30~40℃.

[0019] Preferably, in step S2, vegetable oils containing linoleic acid and / or linolenic acid are selected for mixing. Premixing and compounding vegetable oils containing linoleic acid or rich in linolenic acid can meet the precise control of the characteristic fatty acid ratio. More preferably, the vegetable oil includes at least one of soybean oil, rapeseed oil, peanut oil, corn oil, sunflower seed oil, olive oil, flaxseed oil, sesame oil, cottonseed oil, palm oil, coconut oil, rice bran oil, camellia oil, grapeseed oil, walnut oil, and safflower seed oil. Preferably, in the vegetable oil base, the mass ratio of linoleic acid to linolenic acid is 4 to 6:1.

[0020] Preferably, step S2 is carried out under light-proof and sealed conditions to obtain a stable vegetable oil base.

[0021] Preferably, in step S3, the heating temperature is 60~70℃, and the high-temperature fusion ensures that the vegetable oil base and the low-melting-point component B are fully and uniformly mixed.

[0022] Preferably, the liquid mixture comprises 10-25 parts by weight of low-melting-point component B and 75-90 parts by weight of vegetable oil base.

[0023] Preferably, step S3 is carried out under a sealed protective gas (such as nitrogen or inert gas) to avoid oxidation and retain characteristic flavor substances to the maximum extent.

[0024] Preferably, in step S4, the powder of the high melting point component A is added to the liquid oil mixture at 30~40°C to better form fine and uniform β' crystals and suppress the formation of coarse β crystals.

[0025] Preferably, the amount of powder of the high melting point component A added is 0.5% to 3% of the total mass of the liquid oil mixture.

[0026] Preferably, the powder of the high-melting-point component A is added in batches to control crystallization and suppress the formation of coarse crystals.

[0027] Preferably, the powder of the high melting point component A is 100-200 mesh.

[0028] Preferably, the low-temperature freezing temperature of the high-melting-point component A is -20℃ to -40℃. Preferably, in step S5, the temperature is lowered to 15-20°C for crystallization.

[0029] More preferably, the cooling rate is 1–2 °C / h.

[0030] More preferably, crystal growth is carried out at a constant temperature under sealed and light-proof conditions.

[0031] More preferably, the isothermal crystal growth time is 2 to 4 hours.

[0032] Preferably, the lard-vegetable oil blending process of the present invention includes the following steps: S1 Lard Extraction: In a sealed protective gas atmosphere, lard is heated to 50-60℃ to melt, then cooled to 20-30℃ at a rate of 1-3℃ / h to crystallize, and then kept at a constant temperature in a sealed environment for 12-24 hours to separate high-melting-point component A and low-melting-point component B; the high-melting-point component A includes saturated triglycerides, and the low-melting-point component B includes unsaturated triglycerides. S2 Vegetable Oil Base Material Preparation: At least one type of vegetable oil is selected and mixed under light-proof and sealed conditions to obtain a vegetable oil base. S3 low-melting-point component blended with vegetable oil base: Under a closed protective gas atmosphere, the low melting point component B obtained in step S1 is heated to 60~70℃ to fuse with the vegetable oil base obtained in step S2 to obtain a liquid mixture. S4 high-melting-point component induces crystallization: The high-melting-point component A obtained in step S1 is cryogenically pulverized into 100-200 mesh powder. Samples are taken at 0.5% to 3% of the total mass of the liquid oil mixture and added in batches at 30-40°C to the liquid mixture obtained in step S3 to induce the formation of β'-type microcrystals and form an oil system. S5 Cooling and Shaping: The oil system obtained in step S4 is cooled to 15-20℃ at a rate of 1-2℃ / h to crystallize, and then kept in a sealed, light-proof, constant-temperature environment for 2-4 hours to allow it to settle naturally, thus obtaining the finished product of lard-vegetable oil blend.

[0033] The present invention also provides a lard-vegetable oil blend prepared by the above-described preparation process.

[0034] The lard-vegetable blended oil preparation process provided by this invention first involves low-temperature fractionation to classify lard, obtaining a high-melting-point component rich in saturated triglycerides and a low-melting-point component rich in unsaturated triglycerides. Then, the components are fused in stages: first, the low-melting-point component rich in unsaturated triglycerides is homogenized and fused with vegetable oil at high temperature; then, the micro-powder of the high-melting-point component is used as a nucleus to induce the formation of fine and uniform β' crystals. Further cooling and stabilization are then performed to obtain a stable vegetable oil-lard blended oil system. Compared with existing technologies, the preparation process of this invention has the following advantages: 1. No additives in the process, clean and self-stabilized product: By extracting and separating functional components from lard, high-melting-point components are used as natural crystal nuclei to replace traditional emulsifiers and thickeners. No artificial synthetic additives are required, which can achieve system stability and meet the consumer trend of additive-free and clean label food.

[0035] 2. Good high and low temperature stability of the product: By pre-cooling and separating the high melting point components, and then using the high melting point component micro powder after freeze-pulverization as crystal nuclei to induce the formation of refined crystal forms, the product obtained by controlling the cooling and crystallization process shows no stratification, turbidity, or crystal precipitation when stored at 4℃ low temperature, room temperature, or 50℃ high temperature accelerated storage, and the shelf life stability is greatly improved.

[0036] 3. Precise and controllable fatty acid ratio: By blending high and low melting point components of lard and adjusting the ratio of vegetable oil base, the ratio of saturated fatty acids: monounsaturated fatty acids: polyunsaturated fatty acids = 1:1:1 ± 0.1 and linoleic acid: linolenic acid = 4~6:1 can be stably achieved, reaching the golden nutritional ratio recommended by the World Health Organization.

[0037] 4. High retention of characteristic flavor of lard: Low-temperature extraction, segmented low-temperature intervention, and closed oxygen control process avoid the volatilization and oxidation of heat-sensitive flavor substances caused by one-time high-temperature blending, resulting in rich original flavor of lard with high degree of reduction.

[0038] 5. Longer shelf life due to antioxidant properties: The preparation process of this invention is completely sealed, protected from light, and protected by a protective gas, which effectively inhibits the oxidative rancidity of polyunsaturated fatty acids, reduces the rate of increase in acid value and peroxide value, and extends the shelf life of the product.

[0039] 6. Strong industrial adaptability: The preparation process parameters of this invention have a wide range, good controllability, and strong replicability. It can be adapted to intermittent batch production and continuous assembly line processing, which facilitates industrialization and promotion. Attached Figure Description

[0040] Figure 1 These are product images of the blended oil from Example 1 of the present invention before and after storage at 4°C for 60 days; Figure 2 These are product images of the blended oil from Comparative Example 1 of this invention before and after storage at 4°C for 60 days. Detailed Implementation

[0041] To enable those skilled in the art to more clearly understand the technical solutions described in this invention, the following embodiments are provided for illustration. It should be noted that the following embodiments do not constitute a limitation on the scope of protection claimed by this invention.

[0042] Unless otherwise specified, the raw materials, reagents or devices used in the following examples are available from conventional commercial sources or can be obtained by existing known methods.

[0043] All raw materials used in the embodiments of this invention are food-grade commercially available raw materials.

[0044] Example 1 This embodiment provides a lard-vegetable oil blend, the raw materials of which are as follows: 20kg of refined edible pork fat, 70kg of soybean oil, and 10kg of flaxseed oil.

[0045] Soybean oil: Linoleic acid content is approximately 58 wt%, and linolenic acid content is approximately 5 wt%. Flaxseed oil: Linoleic acid content is approximately 14wt%, and linolenic acid content is approximately 45wt%.

[0046] The preparation process of this blended oil includes the following steps: (1) Lard fractionation Take 20 kg of refined pork fat and heat it to 55°C until it is completely melted. Protect it with nitrogen gas and cool it to 25°C at a rate of 2°C / h. Maintain the temperature and seal it for crystal growth for 18 hours. Separate the components by plate and frame filter press to obtain about 3.5 kg of high melting point component A (melting point 42-46°C) and about 16 kg of low melting point component B (melting point <25°C).

[0047] (2) Preparation of vegetable oil base material 70 kg of soybean oil and 10 kg of flaxseed oil were stirred in a dark, sealed environment at 35°C for 15 minutes to produce 80 kg of vegetable oil base material. The mass ratio of linoleic acid to linolenic acid met the standard of 5:1.

[0048] (3) Blending of low-melting-point components with vegetable oil base Take 15 kg of low melting point component B and 80 kg of vegetable oil base and put them into the reaction vessel. Heat the mixture to 65°C and stir at 300 rpm for 15 min under nitrogen protection to obtain a homogeneous liquid oil mixture.

[0049] (4) High melting point micro powder crystallization The high melting point component A was cryogenically pulverized to 150 mesh at -30℃. 1.5 kg of the mixture was added to the oil mixture obtained in step (3) in 3 portions over 1 hour under constant temperature stirring at 35℃. The mixture was stirred for 20 minutes to disperse it evenly.

[0050] (5) Cooling and shaping The temperature is lowered to 18℃ at a rate of 1.5℃ / h, and the crystals are grown in a sealed, light-proof, and constant-temperature environment for 3 hours. After natural standing, the finished product is aseptically filled.

[0051] Example 2 This embodiment provides a lard-vegetable oil blend, the raw materials of which are as follows: Ingredients: 25kg refined edible pork fat, 65kg corn oil, 10kg perilla seed oil.

[0052] Corn oil: Linoleic acid content approximately 56 wt%, linolenic acid content approximately 0.1 wt%; Perilla seed oil: Linoleic acid content is about 15wt%, and linolenic acid content is about 70wt%.

[0053] The preparation process of this blended oil includes the following steps: (1) Lard fractionation Take 25 kg of refined pork fat and heat it to 55°C until it is completely melted. Protect it with nitrogen gas and cool it to 30°C at a rate of 1.5°C / h. Maintain the temperature and seal for crystal growth for 18 hours. Separate the components by plate and frame filter press to obtain approximately 4.2 kg of high-melting-point component A (melting point 38-42°C) and approximately 20 kg of low-melting-point component B (melting point <25°C).

[0054] (2) Preparation of vegetable oil base material 45 kg of corn oil and 30 kg of perilla seed oil were stirred in a dark, sealed container at 35°C for 15 minutes to obtain 75 kg of vegetable oil base material. The mass ratio of linoleic acid to linolenic acid met the standard of 5:1.

[0055] (3) Blending of low-melting-point components with vegetable oil base Take 20 kg of low melting point component B and 75 kg of vegetable oil base and put them into the reaction vessel. Heat to 65°C and stir at 300 rpm for 15 min under nitrogen protection to obtain a homogeneous liquid oil mixture.

[0056] (4) High melting point micro powder crystallization High melting point component A was cryogenically pulverized to 150 mesh at -30℃. 1.5 kg of the mixture was added to the oil mixture obtained in step (3) in three portions over 40 min at a constant temperature of 35℃. The mixture was stirred continuously for 20 min to disperse it evenly.

[0057] (5) Cooling and shaping The temperature is lowered to 18℃ at a rate of 1.5℃ / h, and the crystals are grown in a sealed, light-proof, and constant-temperature environment for 3 hours. After natural standing, the finished product is aseptically filled.

[0058] Example 3 This embodiment provides a lard-vegetable oil blend, with the same raw materials as in Embodiment 1.

[0059] The preparation process of this blended oil includes the following steps: (1) Lard fractionation Take 20 kg of refined pork fat and heat it to 55°C until it is completely melted. Protect it with nitrogen gas and cool it to 25°C at a rate of 5°C / h. Crystallize it at a constant temperature in a sealed environment for 18 hours. Separate it by plate and frame filter press to obtain approximately 3.05 kg of high-melting-point component A (melting point 38-44°C), which is mainly composed of highly saturated triglycerides; and approximately 16.5 kg of low-melting-point component B (melting point <25°C), which is enriched with unsaturated triglycerides and characteristic flavor substances of pork fat.

[0060] (2) Preparation of vegetable oil base material Same as Example 1.

[0061] (3) Blending of low-melting-point components with vegetable oil base Take 15 kg of low melting point component B and 80 kg of vegetable oil base and put them into the reaction vessel. Heat the mixture to 65°C and stir at 300 rpm for 15 min under nitrogen protection to obtain a homogeneous liquid oil mixture.

[0062] (4) High melting point micro powder crystallization High melting point component A was cryogenically pulverized to 150 mesh at -30℃. 1.5 kg of the mixture was added in two portions to the oil mixture obtained in step (3) within 50 min under constant temperature stirring at 35℃. The mixture was stirred for 20 min to disperse it evenly.

[0063] (5) Cooling and shaping The temperature is lowered to 18℃ at a rate of 1.5℃ / h, and the crystals are grown in a sealed, light-proof, and constant-temperature environment for 3 hours. After natural standing, the finished product is aseptically filled.

[0064] Example 4 This embodiment provides a lard-vegetable oil blend, with the same raw materials as in Embodiment 1.

[0065] The preparation process of this blended oil includes the following steps: (1) Lard fractionation Take 20 kg of refined pork fat and heat it to 55°C until it is completely melted. Protect it with nitrogen gas and cool it to 35°C at a rate of 2°C / h. Crystallize it at a constant temperature in a sealed environment for 18 hours. Separate it by plate and frame filter press to obtain approximately 3.15 kg of high-melting-point component A (melting point 44-48°C), which is mainly composed of highly saturated triglycerides; and approximately 16.4 kg of low-melting-point component B (melting point <28°C), which is enriched with unsaturated triglycerides and characteristic flavor substances of pork fat.

[0066] (2) Preparation of vegetable oil base material Same as Example 1.

[0067] (3) Blending of low-melting-point components with vegetable oil base Take 15 kg of low melting point component B and 80 kg of vegetable oil base and put them into the reaction vessel. Heat the mixture to 65°C and stir at 300 rpm for 15 min under nitrogen protection to obtain a homogeneous liquid oil mixture.

[0068] (4) High melting point micro powder crystallization High melting point component A is cryogenically pulverized to 150 mesh, and 1.5 kg is taken and slowly added in portions to the oil mixture obtained in step (3) under constant temperature stirring at 35℃. The mixture is stirred for 20 minutes to disperse evenly.

[0069] (5) Cooling and shaping The temperature is lowered to 18℃ at a rate of 1.5℃ / h, and the crystals are grown in a sealed, light-proof, and constant-temperature environment for 3 hours. After natural standing, the finished product is aseptically filled.

[0070] Example 5 This embodiment provides a lard-vegetable oil blend, with the same raw materials as in Embodiment 1.

[0071] The preparation process of this blended oil includes the following steps: (1) Lard fractionation Take 20 kg of refined pork fat and heat it to 55°C until it is completely melted. Protect it with nitrogen gas and cool it to 25°C at a rate of 2°C / h to obtain approximately 2.5 kg of high-melting-point component A (melting point 42-46°C), which is mainly composed of highly saturated triglycerides; and approximately 17 kg of low-melting-point component B (melting point <26°C), which is enriched with unsaturated triglycerides and characteristic flavor substances of pork fat.

[0072] (2) Preparation of vegetable oil base material Same as Example 1.

[0073] (3) Blending of low-melting-point components with vegetable oil base Take 15 kg of low melting point component B and 80 kg of vegetable oil base and put them into the reaction vessel. Heat the mixture to 65°C and stir at 300 rpm for 15 min under nitrogen protection to obtain a homogeneous liquid oil mixture.

[0074] (4) High melting point micro powder crystallization High melting point component A is cryogenically pulverized to 150 mesh, and 1.5 kg is taken and slowly added in portions to the oil mixture obtained in step (3) under constant temperature stirring at 35℃. The mixture is stirred for 20 minutes to disperse evenly.

[0075] (5) Cooling and shaping The temperature is lowered to 18℃ at a rate of 1.5℃ / h, and the crystals are grown in a sealed, light-proof, and constant-temperature environment for 3 hours. After natural standing, the finished product is aseptically filled.

[0076] Example 6 This embodiment provides a lard-vegetable oil blend, with the same raw materials as in Embodiment 1.

[0077] The preparation process of this blended oil includes the following steps: (1) Lard fractionation Same as Example 1.

[0078] (2) Preparation of vegetable oil base material Same as Example 1.

[0079] (3) Blending of low-melting-point components with vegetable oil base Take 15 kg of low melting point component B and 80 kg of vegetable oil base and put them into the reaction vessel. Heat the mixture to 65°C and stir at 300 rpm for 15 min under nitrogen protection to obtain a homogeneous liquid oil mixture.

[0080] (4) High melting point micro powder crystallization High melting point component A is cryogenically pulverized to 150 mesh, and 5 kg is taken and slowly added to the oil mixture obtained in step (3) in 5 portions under constant temperature stirring at 35℃. The mixture is stirred for 20 minutes to disperse evenly.

[0081] (5) Cooling and shaping The temperature is lowered to 18℃ at a rate of 1.5℃ / h, and the crystals are grown in a sealed, light-proof, and constant-temperature environment for 3 hours. After natural standing, the finished product is aseptically filled.

[0082] Example 7 This embodiment provides a lard-vegetable oil blend, with the same raw materials as in Embodiment 1.

[0083] The preparation process of this blended oil includes the following steps: (1) Lard fractionation Same as Example 1.

[0084] (2) Preparation of vegetable oil base material Same as Example 1.

[0085] (3) Blending of low-melting-point components with vegetable oil base Same as Example 1.

[0086] (4) High melting point micro powder crystallization Same as Example 1.

[0087] (5) Cooling and shaping Cool to room temperature (approximately 25°C) at a rate of 2°C / h, keep sealed and protected from light for 3 hours to maintain constant temperature and crystal growth, and then allow to stand naturally before aseptic filling to obtain the finished product.

[0088] The blended oils obtained in the above embodiments and comparative examples were tested, and the test results are shown in Table 1.

[0089] Example 8 This embodiment provides a lard-vegetable oil blend, with the same raw materials as in Embodiment 1.

[0090] The preparation process of this blended oil includes the following steps: (1) Lard fractionation In an air environment, 20 kg of refined pork fat was heated to 55°C until completely melted, then cooled to 25°C at a rate of 2°C / h, and cultured in a sealed environment at a constant temperature for 18 hours. The mixture was then separated by plate and frame filter press to obtain approximately 3.5 kg of high-melting-point component A (melting point 42-46°C), which is mainly composed of saturated triglycerides; and approximately 16 kg of low-melting-point component B (melting point <25°C), which is enriched with unsaturated triglycerides and characteristic flavor substances of pork fat.

[0091] (2) Preparation of vegetable oil base material 70 kg of soybean oil and 10 kg of flaxseed oil were stirred at 35°C for 15 minutes to produce 80 kg of vegetable oil base material. The mass ratio of linoleic acid to linolenic acid met the standard of 5:1.

[0092] (3) Blending of low-melting-point components with vegetable oil base Take 15 kg of low melting point component B and 80 kg of vegetable oil base and put them into the reaction vessel. Heat the mixture to 65°C and stir at 300 rpm for 15 min in air to obtain a homogeneous liquid oil mixture.

[0093] (4) High melting point micro powder crystallization High melting point component A is cryogenically pulverized to 150 mesh, and 1.5 kg is taken and added to the oil mixture obtained in step (3) in 3 portions within 1 hour under constant temperature stirring at 35℃. The mixture is stirred continuously for 20 minutes to disperse evenly.

[0094] (5) Cooling and shaping The temperature is lowered to 18℃ at a rate of 1.5℃ / h, and the crystals are kept at a constant temperature for 3 hours under natural conditions. After standing, the product is aseptically filled to obtain the finished product.

[0095] Comparative Example 1 (Traditional Process) This embodiment provides a lard-vegetable oil blend, with the same raw materials as in Embodiment 1.

[0096] The preparation process of this blended oil includes the following steps: 20 kg of refined pork fat is heated directly to 70°C until completely melted, then mixed with 50 kg of soybean oil and 30 kg of flaxseed oil in one go. After cooling at room temperature, it is bottled.

[0097] The blended oils obtained in the above embodiments and comparative examples were tested, and the test results are shown in Table 1 and... Figure 1-2 As shown.

[0098] All testing methods used were performed in accordance with the current national standards GB 2716-2018 "National Food Safety Standard for Vegetable Oils", GB 5009.168-2016 "National Food Safety Standard for Determination of Fatty Acids in Foods", and GB / T 35877-2018 "Determination of Polar Components (PC) in Edible Vegetable Oils During Frying". All tests were conducted in triplicate, and the average value of the results was taken.

[0099] Test method description: 1. Determination of fatty acid composition and ratio Referring to GB 5009.168-2016 Method I, gas chromatography, after the sample was methylated, it was separated and detected by gas chromatography. The mass percentages of saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), and polyunsaturated fatty acids (PUFA), as well as the mass ratios of linoleic acid (C18:2) and linolenic acid (C18:3) were calculated.

[0100] 2. Melting point determination Referring to GB / T 5536-2008 "Test Method for Melting Point of Vegetable Oils", the sliding melting point of oil samples was determined by capillary method. The determination was performed in triplicate with an error ≤0.5℃.

[0101] 3. Low-temperature storage stability test The oil sample to be tested was sealed in a colorless and transparent sample bottle and placed in a constant temperature refrigerator at (4±1)℃. The appearance was observed at 7d, 15d, 30d and 60d respectively, and the presence of turbidity, crystal precipitation, layering and precipitation was recorded.

[0102] 4. High-Temperature Accelerated Stability Test The oil sample to be tested was sealed in a colorless and transparent sample bottle and placed in a constant temperature oven at (50±1)℃ for accelerated storage. The homogeneity of the system was observed at 7d, 15d and 30d respectively, and the occurrence of stratification, oil separation and flocculation was recorded.

[0103] 5. Determination of physicochemical indicators Acid value (AV) determination shall be performed in accordance with GB 5009.229-2016; Peroxide value (POV) determination shall be performed in accordance with GB 5009.227-2016; The crystal form was observed using a polarizing microscope at a magnification of 400x.

[0104] 6. Flavor retention evaluation A professional sensory evaluation team of 10 people (5 men and 5 women, all of whom have received training in oil flavor evaluation) was formed. The team used a 10-point scoring system, with the characteristic flavor of fresh refined lard as the maximum score of 10 points. The team comprehensively evaluated the flavor intensity, reproducibility, and absence of off-odors of the finished lard and calculated the average score.

[0105] Formula for calculating flavor retention improvement rate: Flavor retention improvement rate (%) = (Score of this invention process - Score of traditional process) ÷ Score of traditional process × 100%.

[0106] in Figure 1 These are product images of the blended oil from Example 1 of the present invention before and after refrigeration at 4°C for 60 days. Figure 2The images show the blended oil of Comparative Example 1 of this invention before and after refrigeration at 4°C for 60 days. The container volume in the images is 500 mL.

[0107] Table 1 Test results of the examples and comparative examples

[0108] The results of Examples 1-9 and Comparative Example 1 show that the embodiments of this application improve upon the traditional direct heating and mixing process of Comparative Example 1 in terms of component content, stability, flavor, and physicochemical properties. In Comparative Example 1, the sample began to separate into layers upon being filled and left to stand at room temperature. When testing the content of each component, saturated fatty acids precipitated at the bottom layer, resulting in a low content of saturated fatty acids in the upper oil phase, leading to significant deviations in component composition. In contrast, the low-temperature fractionation followed by segmented fusion process of this invention significantly improves the high and low temperature fusion performance of the product compared to the traditional direct heating and mixing process. No separation or oil precipitation was observed during 60 days of refrigerated storage at 4°C and 30 days of accelerated storage at 50°C. Furthermore, the acid value and peroxide value of the product were also significantly improved. Compared to Example 1, in Example 3, due to the excessively rapid cooling rate during the lard fractionation stage, a large amount of mother liquor (low-melting-point components) was carried over during the crystallization process. This resulted in the high-melting-point component A containing too many low-melting-point unsaturated triglycerides, leading to insufficient crystal nuclei during induced crystallization. The crystals grew freely, forming coarse β-crystals and agglomerating significantly, affecting the system's stability. However, it was still significantly better than Comparative Example 1. In Example 4, the crystallization temperature was too high during the lard fractionation stage, resulting in fewer saturated triglycerides in the precipitated high-melting-point component A and fewer saturated triglycerides in the low-melting-point component B. In Example 5, some saturated fatty acids were retained, which affected crystallization during induction, resulting in a system stability lower than that of Example 1, but still significantly improved compared to Comparative Example 1. In Example 6, excessive micronized powder was added to induce crystallization, leading to too many fine crystals. This caused the fine crystals to easily agglomerate and form flocculations, resulting in a system stability lower than that of Example 1, but still significantly improved compared to Comparative Example 1. In Example 7, the cooling temperature was too high during the cooling and setting process, leading to incomplete crystallization and affecting subsequent storage stability, but still significantly improved compared to Comparative Example 1. In Example 8, the product was prepared in a natural environment, lacking nitrogen protection and a closed, light-proof crystal growth system. The flavor and physicochemical properties of the product were significantly lower than in other examples, but still significantly improved compared to Comparative Example 1. Furthermore, the oxidation of triglycerides altered the molecular structure, disrupting the original crystal arrangement and interfering with crystal formation, thus affecting stability. Comparative Example 1 used a traditional method of direct heating and fusion. The high and low melting point components were not separated, graded, or directionally formulated. The melting and mixing lacked an ordered miscibility process, resulting in unreasonable component content and chaotic system order. Therefore, the effect was significantly worse than in the other examples.

[0109] Lard contains triglycerides and characteristic flavor compounds, with triglycerides being the main component (approximately 98%–99%). Based on saturation, triglycerides can be classified into saturated and unsaturated triglycerides. Saturated triglycerides include trisaturated, disaturated, and monosaturated triglycerides, while unsaturated triglycerides include monounsaturated, diunsaturated, and fully unsaturated triglycerides. Saturated triglycerides have higher melting points than unsaturated triglycerides. The preparation process of this invention, by controlling the temperature and heating rate, first classifies lard based on low-temperature fractionation to obtain a high-melting-point component rich in highly saturated triglycerides and a low-melting-point component rich in unsaturated triglycerides, thus achieving the separation of different components. The highly saturated triglycerides that easily form coarse β-crystals are retained in the high-melting-point component, and then fused in stages. First, the low-melting-point component rich in unsaturated triglycerides is homogenized and fused with vegetable oil at high temperature, and then the high-melting-point component's frozen micro powder is used as a crystal nucleus to induce crystallization in the system. This reduces the amount of highly saturated triglycerides that easily form coarse β-crystals added, and also facilitates the formation of fine and uniform β' crystals in the system. Further cooling and stabilization yields a stable vegetable oil-lard blended system, which greatly improves the problem of poor high and low temperature stability of traditional direct-mixed products. Moreover, by refining the high and low melting point components of lard and adjusting the proportion of vegetable oil base, the fatty acid ratio of the resulting blended oil is controllable. The process is carried out under protective gases such as nitrogen or in a closed and light-proof environment to avoid oxidation, resulting in good flavor retention and acid value and peroxide value that are far superior to national standards.

[0110] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A process for preparing a blended lard-vegetable oil, characterized in that, Includes the following steps: S1 Lard Extraction: Lard is heated and melted, then cooled and crystallized to obtain a high-melting-point component A and a low-melting-point component B; the high-melting-point component A includes saturated triglycerides, and the low-melting-point component B includes unsaturated triglycerides. S2 Vegetable Oil Base Material Preparation: Select at least one vegetable oil and mix them to obtain a vegetable oil base; S3 low-melting-point component blended with vegetable oil base: Heating causes the low-melting-point component B obtained in step S1 and the vegetable oil base obtained in step S2 to be fused together to obtain a liquid mixture; S4 high-melting-point component induces crystallization: The high-melting-point component A obtained in step S1 is cryogenically pulverized into powder and added to the liquid mixture obtained in step S3 to induce the formation of β'-type microcrystals, thus forming an oil system. S5 Cooling and Shaping: The oil system obtained in step S4 is cooled to crystallize, and then kept at a constant temperature to grow crystals. After standing and stabilizing, the lard-vegetable oil blended product is obtained.

2. The preparation process according to claim 1, characterized in that, In step S1, the lard that has been heated and melted is cooled to 20-30℃ to crystallize; And / or, step S1 is performed under the protection of a closed protective gas; And / or, the high melting point component A has a melting point of 38–48°C; the low melting point component B has a melting point of <28°C.

3. The preparation process according to claim 2, characterized in that, In step S1, the lard is heated to 50-60℃ to melt; And / or, cool to 20-30℃ at a rate of 1-3℃ / h to allow crystallization; And / or, after cooling to 20-30℃, maintain the temperature and seal for crystal growth for 12-24 hours.

4. The preparation process according to claim 1, characterized in that, In step S2, the mixing temperature of the vegetable oils is 30~40℃; And / or, the vegetable oil is a vegetable oil containing linoleic acid and / or linolenic acid; And / or, the vegetable oil includes at least one of soybean oil, rapeseed oil, peanut oil, corn oil, sunflower seed oil, olive oil, flaxseed oil, sesame oil, cottonseed oil, palm oil, coconut oil, rice bran oil, camellia oil, grapeseed oil, walnut oil, and safflower seed oil; And / or, step S2 is performed under light-proof and sealed conditions.

5. The preparation process according to claim 1, characterized in that, In step S3, the heating temperature is 60~70℃; And / or, by weight, the liquid mixture comprises 10 to 25 parts of low-melting-point component B and 75 to 90 parts of vegetable oil base; And / or, step S3 is performed under the protection of a sealed protective gas.

6. The preparation process according to claim 1, characterized in that, In step S4, the powder of the high melting point component A is added to the liquid oil mixture at 30~40°C.

7. The preparation process according to claim 6, characterized in that, In step S4, the amount of powder of the high melting point component A added is 0.5% to 3% of the total mass of the liquid oil mixture; And / or, the powder of the high melting point component A is added in batches; And / or, the powder particle size of the high melting point component A is 100~200 mesh; And / or, the cryogenic freezing temperature of the high melting point component A is -20 to -40°C.

8. The preparation process according to claim 1, characterized in that, In step S5, the temperature is lowered to 15-20°C to allow crystals to form.

9. The preparation process according to claim 8, characterized in that, In step S5, the temperature is lowered to 15-20℃ at a rate of 1-3℃ / h to induce crystallization; And / or, the isothermal crystal growth is carried out under sealed and light-proof conditions; And / or, the isothermal crystal growth time is 2~4h.

10. The lard-vegetable oil blend prepared by the preparation process according to any one of claims 1-9.

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