Method for extracting mixed woody grease by water extraction method based on oil compounding optimization

Abstract

The invention discloses a method for extracting mixed woody grease by an aqueous extraction method based on oil compounding optimization. The method comprises the following steps: S1, raw material preparation and pretreatment: selecting dry walnut kernels as main oil and one or more herbal seeds as auxiliary oil; cleaning and shelling (if needed) the main oil and the auxiliary oil; s2, compounding and crushing: accurately compounding the pretreated walnut oil material and auxiliary oil material according to a dry basis weight ratio, uniformly mixing, and jointly crushing or grinding to obtain compound oil material slurry or powder; and S3, water extraction: putting the compound oil slurry or powder into water extraction equipment, adding extraction water at a certain temperature, stirring and oscillating under specific process parameters, and completing replacement and preliminary separation of oil from a solid matrix, so as to obtain the high-quality compound walnut-based edible vegetable oil.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of food, and particularly relates to a method for extracting mixed woody oil based on oil compound optimization by a water displacement method. BACKGROUND

[0002] Plant oil extraction technology is the core of food and oil industry. Traditional extraction methods mainly include mechanical pressing method (cold pressing / heat pressing), solvent extraction method, and rapidly developed physical methods such as supercritical CO2 extraction in recent years. Each method has its own advantages and disadvantages: the pressing method is safe but has a low oil yield; the solvent extraction method is efficient but has the risk of solvent residue and destruction of nutritional components; the supercritical extraction method has high quality but high equipment investment and operation cost.

[0003] As an ancient oil production process, the principle of the water displacement method (Aqueous Extraction Method) is to use the difference in the affinity of non-oil components (mainly protein and carbohydrate) in oil materials for oil and water, and the different specific gravities of oil and water, to displace and separate oil from solid substances such as protein through steps such as water addition, stirring, and oscillation. This method has the advantages of simple process, no use of organic solvents, safe production, good retention of heat-sensitive nutritional components (such as vitamin E and polyphenols) in oil at low temperatures, and simultaneous recovery of protein, and is particularly suitable for the production of specialty oils such as sesame oil. In recent years, with the pursuit of green and clean production technology, the application of water displacement method and its derivative technology (such as aqueous enzymatic method) in woody oil processing has increased.

[0004] However, the direct application of the water displacement method to woody oil materials such as walnuts, oil tea seeds, and almonds, especially to oil materials with high protein content, faces a series of technical bottlenecks that have not been effectively solved for a long time: 1. The strong emulsifying effect of protein makes it difficult for oil and water to separate, and it is highly dependent on the type of oil: The protein in oilseeds (usually between 5%-40%) has excellent emulsifying and foaming properties. During the water displacement process, protein is extremely easy to form a stable interface film at the oil-water interface, resulting in the formation of a highly stable emulsion (O / W or W / O). The stability of this emulsion is a key technical bottleneck that restricts the efficiency and yield of oil extraction by water displacement (and enzymatic hydrolysis). The existing technology usually needs to adjust the pH value, add electrolytes, centrifuge or long time standing and other complex and energy-consuming subsequent demulsification steps, which not only increases the process complexity and cost, but also may introduce foreign substances or cause oil hydrolysis and spoilage. The current successful application of water displacement method in industry is mainly limited to sesame. This is because sesame contains unique sesame globulin and sesame phenol and other substances, which can form a stable water-in-oil emulsion under certain process conditions and then demulsify to achieve oil-water separation. Many other woody oilseeds (such as walnut, almond, camellia seed, etc.) or protein-containing oilseeds (such as peanut, flaxseed), due to their differences in protein composition, content, structure and cell structure from sesame, if the water displacement process parameters (such as water addition amount, water temperature, stirring intensity and time) of sesame are directly applied, often appear problems such as low oil yield, serious oil-water emulsification and difficult separation, or viscous protein slurry and residue that cannot be smoothly "skimmed", etc., leading to process failure or extremely low efficiency.

[0005] 2. The harsh requirements of single oil on process parameters and poor universality: The water displacement process in the existing technology for a certain single non-sesame oil (such as walnut) is often "tailored" for this specific oil, which is difficult to directly apply to other oils. If multiple oils are to be processed, the process needs to be frequently adjusted, lacking universality and stability. The cell structure, chemical composition (such as protein type and content, oil form, cellulose content) of different oils differ greatly. For example, the physical and chemical properties of walnut kernels, flaxseed, peanut, and camellia seed are quite different. This makes it difficult to directly apply the water displacement process parameters (such as the optimal solid-liquid ratio, temperature, stirring intensity and time) optimized for a single oil (such as walnut) to other oils. For example, Li Wenkan et al. pointed out that the optimal temperature for walnut water displacement is 60-75°C, and the stirring time is 10-18 minutes; while Qian Haojie et al. studied the optimal enzymatic hydrolysis temperature of mountain walnut water-enzyme method is about 54°C, and the solid-liquid ratio is 1:5. If walnut process parameters are used to process flaxseed, the system may be viscous due to high gum content, making it difficult to extract oil; conversely, if flaxseed's mild parameters are used to process walnut, the cells may not be broken down sufficiently, resulting in low oil yield. This "one oil-one parameter" characteristic severely limits the scale and universal application of the water displacement method technology.

[0006] 3. The difficulty of balancing oil yield and nutrient retention: In order to improve the oil yield of a single oil, it is often necessary to strengthen the process conditions, such as increasing the temperature, prolonging the stirring time or increasing the mechanical shear force. However, these strengthening measures may exacerbate protein denaturation, oil oxidation and degradation of heat-sensitive nutrients (such as vitamin E and polyunsaturated fatty acids). For example, high temperature is beneficial to demulsification and oil flow, but it can significantly reduce the content of valuable vitamin E and antioxidants in walnut oil. How to maximize the retention of natural nutrients and flavor of oil while ensuring high oil yield is a major challenge for existing water displacement method technology.

[0007] 4. Existing patent technology has not effectively solved the above-mentioned complex problems: Although there are a large number of patents on oil extraction, through retrieval, there is limited patent technology disclosure information directly targeting "water displacement method for extracting woody oil" and systematically solving the above-mentioned protein interference, process universality and nutrient retention problems. Existing technologies are mostly focused on process optimization or equipment improvement for single oil. For example, there are patents related to the development and process optimization of "vertical water displacement method for extracting walnut oil equipment", but the focus is on the structure of the equipment and the optimization of single process parameters for walnut, and it does not involve fundamentally changing the physicochemical properties of the system by compounding oil to overcome common problems. Another technology focuses on "aqueous enzymatic method" by adding exogenous enzymes to assist demulsification and oil extraction, but this increases the cost of enzyme preparation, and the enzyme hydrolysis conditions (pH, temperature, time) are strictly controlled, and the process is complex, and also faces the problem of poor adaptability to different oils.

[0008] Analysis of the closest prior art: Based on the existing information, the closest prior art can be referred to the patent application with publication number CN116836753B and the name "A process and equipment for extracting walnut oil by water displacement method". This technology discloses a special equipment and matching process for extracting walnut oil by water displacement method, and its technical features mainly include: using specific roasting and grinding process to pretreat walnut kernels, then in a horizontal stirring tank, controlling the slurry temperature at 60-75℃, the water addition ratio at 12%-18%, and the stirring time at 10-18 minutes for water displacement extraction, and finally obtaining walnut oil by stirring and centrifugal separation.

[0009] The closest prior art realizes the water replacement method extraction of walnut oil and optimizes its process parameters, but still has the fundamental defects pointed out in the foregoing background art: (1) The process is highly dependent on the characteristics of walnut raw materials, the parameter window is narrow, and it is difficult to be applied to other woody or herbaceous oil plants (such as peanuts, flaxseed, almonds, etc.) with different protein content and gum characteristics, lacking process universality; (2) In order to pursue high oil yield, conditions close to the upper limit of the parameter range (such as higher temperature and longer stirring time) may be used, which poses a potential threat to the retention of heat-sensitive nutrients such as vitamin E in oil; (3) The problem of stable emulsion caused by protein emulsification has not been solved, and the separation efficiency still has room for improvement, and the subsequent complex demulsification process is not considered by designing the raw material level to simplify or eliminate it.

[0010] Therefore, there is an urgent need in the art for an innovative water replacement method extraction technology that can weaken the negative emulsification effect of protein in principle, broaden the adaptability of process parameters, and achieve efficient and high-quality oil extraction from a variety of oil plants (especially woody oil plants rich in protein) without complex external addition or harsh conditions. SUMMARY

[0011] The purpose of the present application is to provide a method for water replacement method extraction of mixed woody oil based on oil material compounding optimization, which solves the technical problem of difficult oil-water separation caused by strong protein emulsification in the single oil material water replacement method extraction of the prior art.

[0012] The technical scheme adopted by the present application to solve its technical problems is: A method for water replacement method extraction of mixed woody oil based on oil material compounding optimization, comprising the following steps: S1, raw material preparation and pretreatment: selecting dry walnut kernels as the main oil material, and one or more herbaceous seed materials as auxiliary oil materials; cleaning and dehulling (if necessary) the main oil material and auxiliary oil material; S2, compounding and crushing: accurately compounding the pretreated walnut oil material and auxiliary oil material according to the dry basis weight ratio, uniformly mixing, and then jointly crushing or grinding to obtain a compounded oil material slurry or powder; S3, water replacement method extraction: placing the compounded oil material slurry or powder in a water replacement method extraction device, adding water for extraction at a certain temperature, and stirring and oscillating under specific process parameters to complete the displacement and preliminary separation of oil from the solid matrix, thereby obtaining high-quality compounded walnut-based edible vegetable oil.

[0013] The method for water replacement method extraction of mixed woody oil based on oil material compounding optimization of the present application, the auxiliary oil material in step s1 is peanut kernel, flaxseed, almond, pine kernel, oil tea seed (camellia seed) or perilla seed.

[0014] The application discloses a method for extracting mixed woody oil by a water replacement method based on oil material compounding optimization.

[0015] The application discloses a method for extracting mixed woody oil by a water replacement method based on oil material compounding optimization.

[0016] The application discloses a method for extracting mixed woody oil by a water replacement method based on oil material compounding optimization.

[0017] The application discloses a method for extracting mixed woody oil by a water replacement method based on oil material compounding optimization.

[0018] The application discloses a method for extracting mixed woody oil by a water replacement method based on oil material compounding optimization.

[0019] The application discloses a method for extracting mixed woody oil by a water replacement method based on oil material compounding optimization. By optimizing the compounding ratio, the total oil yield (calculated by mixed dry material) of the combination of walnut and various auxiliary oil materials can stably reach or exceed 60%, even close to 70% of a high level, and the fluctuation is small, the total oil yield and process stability are significantly improved. By compounding raw materials, the physicochemical properties of the water replacement method system are fundamentally improved, so that a relatively wide set of process parameters can be effectively applied to the combination of "walnut-peanut", "walnut-flaxseed", "walnut-almond" and other oil materials. This completely changes the predicament of the traditional water replacement method "one oil material one set of parameters", greatly improves the universality and equipment utilization rate of the water replacement method technology, provides the possibility for industrialized continuous production of various composite oil products, and reduces the cost and risk of frequent adjustment of the process of enterprises for different oil materials. Efficient inhibition of stable emulsion formation, simplifying the subsequent separation process: As described in the mechanism section, the competitive adsorption of proteins disrupts the formation of a stable interfacial film. Experiments show that the mixed slurry extracted by the compound technology of the present application has a significantly faster speed of static stratification than the single oil extraction system, the oil layer is more clear, and the middle emulsion layer is greatly reduced or even disappears. This significantly reduces the dependence on complex demulsification methods such as high-speed centrifugation, addition of demulsifiers or adjustment of pH, simplifies the process flow, shortens the production cycle, and avoids product contamination or quality degradation caused by the addition of chemicals; Better preservation and synergistic improvement of the nutritional value of oil: High retention rate of heat-sensitive nutrients: Because relatively mild extraction temperature (such as 60-65°C) and shorter extraction time (such as 20-30 minutes) can be used, the present application can minimize the destruction of heat-sensitive and easily oxidized nutrients such as vitamin E, polyphenols, and sterols in walnut oil and other oilseeds[

[52] ][

[53] ]. Comparative experimental data show that the retention rate of vitamin E in the oil obtained by the present application is more than 15% higher than that of the single oilseed high-temperature water extraction method at the same oil yield; The fatty acid composition is more reasonable and unique: The final product is no longer a single walnut oil, but a compound oil based on the flavor of walnut and the natural design of fatty acid spectrum. For example, "walnut-flaxseed (4:1)" compound oil can simultaneously enrich linoleic acid from walnut and α-linolenic acid from flaxseed, and the ratio of Omega-6 to Omega-3 can be adjusted to a healthier range. "Walnut-camellia seed (4:1)" compound oil combines the fragrance of walnut with the antioxidant properties of camellia oil. This nutritional compound achieved through the process is more technically challenging and consistent than simply physically mixing finished oils; The present application achieves a comprehensive improvement in oil extraction efficiency, product quality, and process versatility without increasing the complexity of equipment or the cost of additives, resulting in significant economic benefits. At the same time, the denaturation degree of proteins in the residue after water extraction is relatively low, and the compound residue may have different protein composition and functional properties than single-species residue, providing a better basis for high-value utilization (such as as feed or plant protein raw material), further improving the economic efficiency of the entire processing process; The entire process of the present application uses water as the main medium and does not use organic solvents, eliminating the risk of solvent residue and simplifying wastewater treatment. Compared with leaching, it is safer and more environmentally friendly; compared with supercritical extraction, the equipment investment and energy consumption are greatly reduced. The present application is an important upgrade to the traditional green oil production process, which is in line with the current trend of sustainable development of the food industry, thus being environmentally friendly and meeting the trend of clean production. DETAILED DESCRIPTION

[0020] For the purposes of making the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application are clearly and completely described. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application, and are not used to limit the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0021] The core idea of the present application is that, instead of optimizing the extraction process of a single oil material in isolation, a microenvironment more conducive to water extraction is created by scientific raw material combination design and the interaction of components such as protein, oil and polysaccharide in different oil materials. Specifically, the present application finds that, by compounding walnut oil material with one or more other protein-containing oil materials selected from peanut, flaxseed, almond, pine nut, camellia seed, perilla seed, etc. in a specific ratio, and then using water extraction (using a "device for extracting woody oil by water extraction method") for processing, an unexpected synergistic effect can be produced.

[0022] Example 1: Walnut-Peanut Compound 1. Raw materials: 2000g of shelled walnut kernels and 500g of shelled peanut kernels.

[0023] 2. Pretreatment: sterilize the raw materials with ultraviolet light for 10 minutes.

[0024] 3. Water extraction of oil: pour the oil material into a water extraction device (such as the special device mentioned in the background art), and complete the processes of grinding, water injection, temperature control, stirring and solid-liquid separation in the process of making woody oil through various mechanical devices, with a total time of 50-60 minutes.

[0025] Effect: The oil yield (based on the oil content of the mixed raw materials) reaches 92%. Compared with pure peanut kernel water extraction method (oil yield <70% and serious emulsification), the process is extremely smooth, and the oil-water separation is complete. The oil has the fragrance of walnut and the aroma of peanut.

[0026] Example 2: Walnut-Almond-Flaxseed Compound 1. Raw materials: 2000g of shelled walnut kernels, 250g of sweet almond kernels and 250g of flaxseed (total auxiliary oil material 500g, ratio 4:1).

[0027] 2. Pretreatment: sterilize the raw materials with ultraviolet light for 10 minutes.

[0028] 3. Water displacement to replace oil: Pour the oil into the water displacement extraction equipment (such as the special equipment mentioned in the background art), and through the cooperation of various mechanical devices, complete the processes of grinding, water injection, temperature control, stirring, and solid-liquid separation during the preparation of woody oil, with a total time of 50-60 minutes. (Same as Example 1) Effect: The oil yield reaches 90.5%. The process is smooth. The obtained oil is rich in α-linolenic acid (from flaxseed and walnut), oleic acid (from almond), and vitamin E, with high nutritional value.

[0029] Comparative Example 1: Pure Walnut Kernel Only 2500g of walnut kernels were used, and the same pretreatment and water displacement process parameters as in Example 1 were used.

[0030] Effect: The oil yield is about 88%, but the slurry is relatively sticky during the late stirring period, and there is a slight oil carryover phenomenon in the residue during oil skimming, and the oil yield and residue oil stability are slightly inferior to Example 1.

[0031] Comparative Example 2: Walnut-Peanut Compound Ratio of 3:2 Walnut kernels 1500g, peanut kernels 1000g. Other processes are the same as Example 1.

[0032] Effect: The oil yield decreases to 89%, and the slurry shows a slight emulsification phenomenon in the late period, and the oil layer elution speed is slower than Example 1, and the separation process time is extended. It is shown that after deviating from the optimal ratio of 4:1, the synergistic effect is weakened, and the process advantage is decreased.

[0033] Summary of experimental data: Through the detailed description and data comparison of the above examples and comparative examples, the effectiveness and superiority of the technical scheme of the present application are fully demonstrated. Under the key 4:1 compound ratio, the present application successfully applies the water displacement method to the combined extraction of various protein-containing oil materials, not only ensures a high and stable total oil yield, but also significantly improves the oil-water separation effect, simplifies the process, and produces a compound oil with higher nutritional value and unique flavor under mild conditions. This opens up a new technical path for the green and high-value processing of woody oil and special oil.

[0034] It should be noted that the equipment used in the present application can be CN116836753B, entitled "Water displacement method for extracting walnut oil".

[0035] The technical scheme of the present application can solve the problems in the background art based on the following deep scientific mechanisms, which are verified through experimental observation and theoretical analysis: 1. Protein composition and property complementation and interference weakening effect: Plant proteins from different sources have different amino acid compositions, isoelectric points, hydrophobicities, molecular conformations, and emulsification properties. For example, walnut protein and peanut protein, flaxseed protein differ in molecular properties. When they coexist in a water system at a ratio of 4:1, different protein molecules compete for adsorption at the oil-water interface, which may not form a dense, ordered, and strong interface film like a single protein. This "competitive adsorption" and "interface film heterogeneity" can reduce the mechanical strength and stability of the interface film, thereby spontaneously weakening the stability of the emulsion, making oil droplets more likely to coalesce and float, greatly alleviating the problem of emulsion demulsification. This is equivalent to a "in-situ demulsification" design at the molecular level.

[0036] 2. Optimization of rheological properties of material system: Single oil (such as flaxseed) may result in excessive viscosity of the slurry due to high gum content, which is not conducive to water penetration and oil migration; while walnut kernel has high oil content but different solid matrix properties. By 4:1 compounding, the particle size distribution, water holding capacity and flowability of the overall material can be adjusted. Experiments have found that the compounded slurry at this ratio has more suitable viscosity and flowability, which can ensure that water and material are in full contact and replace oil, and also facilitate subsequent stirring and separation operations, widening the range of operable material liquid ratio and stirring conditions.

[0037] 3. Synergy of thermodynamics and mass transfer process: Under the action of heating and stirring, the difficulty of cell wall rupture and oil release kinetics of different oil materials differ. The compounded system may form a "stepwise" release effect. For example, the cells of some oil materials are more easily broken, and the oil released early may act as a "lubricant" or "carrier" to promote water penetration into the cells of more difficult-to-crush oil materials and facilitate the subsequent release of oil therein. This internal synergistic mass transfer process helps to achieve an increase in total oil yield under relatively mild temperature and time parameters, thereby avoiding the use of excessively harsh process conditions to pursue high oil yield of a single oil material, which is beneficial to the retention of heat-sensitive nutrients.

[0038] 4. Natural fortification and balance of nutrients: 4:1 compounding is not only the need of process optimization, but also the cornerstone of product nutrition design. Walnut oil is rich in omega-3 and omega-6, but different varieties have fluctuations in content. Peanut oil is rich in oleic acid; flaxseed oil is an excellent source of omega-3; camellia seed oil is rich in oleic acid and tea polyphenols; perilla seed oil is rich in alpha-linolenic acid. Through scientific compounding, the fatty acid composition of the final oil can be naturally balanced to make the ratio of saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids more reasonable, and at the same time, the trace nutrients in different oilseeds (such as vitamin E in walnuts and almonds, squalene and tea polyphenols in camellia seeds, etc.) are aggregated to achieve the nutritional value of "1+1>2" improvement. This goes beyond simple mixing and is a natural fusion achieved during extraction.

[0039] It should be understood that, for those of ordinary skill in the art, improvements or changes can be made according to the above description, and all such improvements and changes shall fall within the scope of protection of the appended claims of the present application.

Claims

1. A method for extracting mixed woody oils using a water-displacement method based on optimized oilseed blending, characterized in that, Includes the following steps: S1. Raw material preparation and pretreatment: Select dried walnut kernels as the main oilseed and one or more herbaceous seeds as auxiliary oilseeds; clean and deshell the above-mentioned main and auxiliary oilseeds (if necessary); S2. Compounding and grinding: The pretreated walnut oil and auxiliary oil are precisely compounded according to the dry weight ratio, mixed evenly, and then crushed or ground together to obtain compound oil slurry or powder. S3. Water displacement extraction: The above-mentioned compound oil slurry or powder is placed in a water displacement extraction device, and extraction water at a certain temperature is added. Under specific process parameters, the mixture is stirred and shaken to complete the displacement and preliminary separation of the oil from the solid matrix, thereby obtaining high-quality compound walnut-based edible vegetable oil.

2. The method for extracting mixed woody oils using water displacement based on optimized oilseed blending according to claim 1, characterized in that, The auxiliary oilseeds in step s1 are peanut kernels, flax seeds, almonds, pine nuts, camellia seeds (camellia seeds) or perilla seeds.

3. The method for extracting mixed woody oils using water displacement based on optimized oil compounding according to claim 1, characterized in that, In step s2, the ratio of walnut oilseeds to auxiliary oilseeds by dry weight is 1:1, 3:2, or 4:

1.

4. The method for extracting mixed woody oils using water displacement based on optimized oilseed blending according to claim 3, characterized in that, In step s2, the ratio of walnut oilseeds to auxiliary oilseeds by dry weight is 4:

1.

5. The method for extracting mixed woody oils using water displacement based on optimized oil compounding according to claim 1, characterized in that, The process parameters in step s3 include: material-liquid ratio, extraction temperature, stirring time, and stirring speed.

6. The method for extracting mixed woody oils using water displacement based on optimized oilseed blending according to claim 5, characterized in that, The material-to-liquid ratio is 1:3 to 1:6, the extraction temperature is 55°C to 70°C, the stirring time is 15 to 40 minutes, and the stirring speed is 100 to 300 rpm.

7. The method for extracting mixed woody oils using water displacement based on optimized oil compounding according to claim 2, characterized in that, The auxiliary oilseed is a mixture of peanut kernels or flaxseeds and almonds.

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