Compound vegetable oil, its preparation method and compound oil press

Abstract

This invention relates to the field of vegetable oil technology, and more particularly to compound vegetable oil, its preparation method, and a compound oil press. The preparation method includes: raw material selection: selecting peanuts, camellia seeds, and rapeseed harvested in the current year, and removing shriveled, moldy, insect-damaged, and spoiled raw materials; raw material blending: mixing the obtained peanuts, camellia seeds, and rapeseed in a ratio of 100:(70-90):(10-30) to obtain a mixed raw material; and pressing: adding the mixed raw material to a press for mechanical pressing to obtain the compound vegetable oil. The compound vegetable oil prepared by this method has superior antioxidant properties and can maintain its quality for a longer period under normal storage conditions.

Description

Technical Field

[0001] This invention relates to the field of vegetable oil technology, and more particularly to compound vegetable oils, their preparation methods, and compound oil presses. Background Technology

[0002] With increasing health awareness, more and more people are paying attention to the types and amounts of fats they consume, tending to choose healthier vegetable oils. Vegetable oils, as a common food ingredient in daily life, have the following advantages: First, they are rich in nutrients. Different types of vegetable oils contain different nutrients, such as vitamin E, unsaturated fatty acids, and antioxidants, all beneficial to the human body. Second, they are a healthy choice. Compared to animal fats, vegetable oils typically contain lower levels of saturated fatty acids but are rich in unsaturated fatty acids. Moderate intake of vegetable oils helps maintain cardiovascular health and lower cholesterol levels. Finally, they are sustainable. Vegetable oil production usually relies on crops such as soybeans, rapeseed, and peanuts. Compared to animal fats, vegetable oil production has a smaller environmental impact, contributing to the development of sustainable agricultural models. However, under long-term storage, vegetable oils are prone to oxidation due to their relatively weak antioxidant capacity, leading to nutrient loss and the production of peroxides, aldehydes, and other compounds harmful to human health. Therefore, how to improve the antioxidant capacity of vegetable oils is increasingly attracting the attention of those skilled in the art. Summary of the Invention

[0003] To address or partially address the problems existing in related technologies, this invention provides a compound vegetable oil, its preparation method, and a compound oil press.

[0004] This invention provides a method for preparing a compound vegetable oil, comprising the following steps:

[0005] a) Raw material selection: Select peanuts, camellia seeds and rapeseed produced in the current year, and remove shriveled, moldy, insect-damaged and deteriorated raw materials;

[0006] b) Raw material compounding: The peanuts, camellia seeds and rapeseed obtained in step a) are mixed evenly in a ratio of 100:(70-90):(10-30) to obtain mixed raw materials;

[0007] c) Mixed pressing: The mixed raw materials are added to a press for mechanical pressing to obtain compound vegetable oil.

[0008] Furthermore, step a) further includes a step of pre-treating the selected peanuts by roasting, specifically roasting the peanuts at 120-150℃ for 20-30 minutes.

[0009] Furthermore, in step b), the mixing ratio of peanuts, camellia seeds, and rapeseed is 100:(75-80):(20-25).

[0010] Furthermore, step c) further includes: refining the compound vegetable oil obtained by mechanical pressing, wherein the oil refining includes: degumming, dehydration, decolorization and deodorization.

[0011] The present invention also provides a compound vegetable oil, which is prepared according to any one of the methods described above.

[0012] The present invention also provides a compound oil press, including a feeding unit and a pressing unit, wherein the feeding unit includes: a support platform, a mixing mechanism and a shaking conveying mechanism;

[0013] The mixing mechanism includes a feeding base and a stirring screw. The feeding base is installed on a support platform and, from top to bottom, includes a guide section, a mixing section, and a support section. The guide section includes a pair of guide baffles arranged vertically opposite each other, forming a feeding area between the guide baffles. The mixing section forms a cylindrical mixing space inside, with its top connected to the feeding area and its bottom having a discharge port. The stirring screw is located within the mixing space and is coaxially arranged with the mixing space. The support section includes a pair of opposite support legs, the bottom of which is installed on the support platform. The support platform has a strip-shaped notch at the beginning, and the strip-shaped notch and the discharge port are arranged vertically opposite to the feed port of the pressing unit.

[0014] The vibrating feeding mechanism includes: a drive unit, a lifting plate, and a feeding assembly;

[0015] The material conveying assembly includes: a material conveying pipe group and several feeding hoppers. The material conveying pipe group has several material conveying pipes arranged in parallel along the direction of the discharge port. Each material conveying pipe is arranged vertically and has a material inlet. Several feeding hoppers are respectively installed on several material conveying pipes, and the hopper outlets of the feeding hoppers are connected to the material inlets of the corresponding material conveying pipes. The upper end of the lifting plate is connected to the drive unit and moves up and down along the guide baffle under the action of the drive unit. One side of the material conveying pipe group is fixed to the lifting plate, and the lower end is located in the feeding area and moves up and down along the guide baffle.

[0016] Furthermore, the drive unit includes: a first motor, a crank-slider mechanism, and a guide bracket; the first motor is connected to the axle of the crank wheel of the crank-slider mechanism, and the upper end of the lifting plate is connected to the connecting rod of the crank-slider mechanism; the guide bracket is installed on a support platform, and a track is provided along the vertical direction, and the lifting plate performs a reciprocating lifting motion along the track.

[0017] Furthermore, the conveying pipe assembly is provided with at least three conveying pipes; the bottom surface of the feed hopper is formed with an inclined surface that slopes downward toward the hopper outlet.

[0018] Furthermore, the feeding unit also includes a premixing mechanism, which includes a mixing hopper, a spiral blade, and a second motor. The mixing hopper is mounted on a support platform, and the spiral blade is disposed inside the mixing hopper. The second motor is connected to a rotating shaft at one end of the spiral blade and is used to drive the spiral blade to rotate.

[0019] This invention also provides an industrial production method for compound oils, comprising the following steps:

[0020] d) Raw material selection: Select peanuts, camellia seeds and rapeseed produced in the current year, and remove shriveled, moldy, insect-damaged and spoiled raw materials;

[0021] e) The peanuts, camellia seeds, and rapeseed obtained in step d) are respectively fed into different feed hoppers of the compound oil press described in claim 6 in a ratio of 100:(70-90):(10-30). After being mixed by the feeding unit, they enter the pressing unit for pressing to obtain compound oil.

[0022] The method for preparing the compound vegetable oil provided by this invention can include the following beneficial effects:

[0023] This preparation method uses peanuts, camellia seeds, and rapeseed as raw materials, giving the edible oil higher nutritional value and a harmonious taste. The pressing process employs mixed pressing, which, compared to traditional methods, improves oil extraction efficiency and extends the interaction time between different raw materials, increasing the contact surface area and promoting the formation of more compounds with antioxidant properties. This results in a final compound oil with superior freshness and antioxidant properties, maintaining its quality for a longer period under normal storage conditions.

[0024] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the invention. Attached Figure Description

[0025] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same parts.

[0026] Figure 1 This is a three-dimensional structural schematic diagram of a compound oil press according to an embodiment of the present invention;

[0027] Figure 2 This is a three-dimensional structural schematic diagram of the compound oil press shown in an embodiment of the present invention from another perspective;

[0028] Figure 3This is a three-dimensional structural diagram of the feed base in the compound oil press shown in an embodiment of the present invention;

[0029] Figure 4 This is a schematic diagram of the structure of the feed hopper and conveying pipe in the compound oil press shown in an embodiment of the present invention;

[0030] Figure 5 This is a bar chart comparing the acid values ​​of each group of oils in the embodiments and comparative examples of the present invention;

[0031] Figure 6 This is a bar chart comparing the peroxide values ​​of various groups of oils in the embodiments and comparative examples of the present invention;

[0032] Figure 7 This is a bar chart comparing the ABTS free radical scavenging rates of each group of oils in the embodiments and comparative examples of the present invention;

[0033] Figure 8 This is a bar chart comparing the DPPH removal rates of various groups of oils in the embodiments and comparative examples of this invention.

[0034] Explanation of reference numerals in the attached figures

[0035] 1-Support Platform

[0036] 2-Feeding base

[0037] 21-Guide baffle

[0038] 22-Mixing Space

[0039] 23-Supporting Legs

[0040] 31-Lifting plate

[0041] 32-Material conveying pipeline

[0042] 321-Feeding Inlet

[0043] 33-Feed Hopper

[0044] 34-First Motor

[0045] 35-Guide Bracket

[0046] 41-Mixing Hopper

[0047] 42-Helical Blade

[0048] 43-Second Motor Detailed Implementation

[0049] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular forms “a,” “the,” and “the” used in this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0051] It should be understood that although the terms "first," "second," "third," etc., may be used in this invention to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this invention, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Thus, features defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0052] Single-plant oil extraction utilizes only the seeds or fruits of a specific plant, failing to fully extract the specific components found in other plants. Compound vegetable oils, on the other hand, are blends of various vegetable oils, such as soybean oil, peanut oil, corn oil, and sunflower oil. Compound vegetable oils increase the variety and amounts of unsaturated fatty acids and trace components found in different vegetable oils, resulting in higher nutritional value. Compared to single-plant oil extraction, compound vegetable oils fully utilize the advantages of various raw materials, including higher levels of antioxidants and other trace components, which helps enhance the antioxidant properties of the vegetable oil.

[0053] Currently, common oil extraction methods mainly include mechanical pressing and chemical solvent pressing. Chemical solvent pressing leaves trace amounts of chemical solvents in the vegetable oil, posing a certain health risk. Therefore, the inventors of this application considered using mechanical pressing to prepare compound vegetable oils. Currently, the mechanical pressing method for preparing compound vegetable oils involves separately pressing the raw materials to obtain individual vegetable oils, then mixing and blending the different individual vegetable oils according to a specified ratio. The inventors of this application have found that while the compound oil obtained by this method exhibits improved antioxidant properties compared to single vegetable oils, the improvement is limited.

[0054] To further enhance the antioxidant properties of vegetable oils, the inventors considered that the improved antioxidant properties of compound vegetable oils obtained by blending single vegetable oils might be due to the interaction between trace components in different single vegetable oils, which synergistically exert some antioxidant effects. Based on this idea, the inventors considered how to prolong the duration of the synergistic effect or accelerate its rate to amplify the effect and improve the antioxidant properties of the compound vegetable oil. Furthermore, the inventors considered mechanically pressing the mixed raw materials, utilizing the heating effect generated by mechanical pressing, which effectively increases the reaction temperature between trace components, as well as the contact area and reaction time, in order to amplify the aforementioned synergistic effect.

[0055] Based on the above inventive concept, the inventors of this application have combined different raw materials and obtained compound vegetable oils through the aforementioned mixed physical pressing method. Research has shown that most vegetable oils obtained through this mixed physical pressing method exhibit further improved antioxidant properties compared to blended vegetable oils, and the selection of raw materials has a significant impact on the degree of improvement in antioxidant properties. The compound vegetable oil obtained by physically pressing a mixture of peanuts, camellia seeds, and rapeseed is not only nutritionally balanced and has a rich flavor, but also possesses excellent antioxidant properties.

[0056] Therefore, this application provides a method for preparing a compound vegetable oil, which includes the following steps:

[0057] a) Raw material selection: Select peanuts, camellia seeds and rapeseed produced in the current year, and remove shriveled, moldy, insect-damaged and deteriorated raw materials;

[0058] b) Raw material compounding: The peanuts, camellia seeds and rapeseed obtained in step a) are mixed evenly in a ratio of 100:(70-90):(10-30) to obtain mixed raw materials;

[0059] c) Mixed pressing: The mixed raw materials are added to a press for mechanical pressing to obtain compound vegetable oil.

[0060] In the above preparation method, step a) is the raw material selection step, in which peanuts, camellia seeds, and rapeseed are mixed and pressed. The above three raw materials, when mixed in the above proportions, are not only rich in nutrients and have a harmonious taste, but the trace compounds in the three raw materials also interact during the pressing process to further enhance antioxidant properties. After selecting the raw materials, this step preferably also includes a pre-treatment step of roasting the selected peanuts, specifically roasting the peanuts at 120–150°C for 20–30 minutes. Pre-roasting the peanuts under appropriate conditions helps to increase the oil yield.

[0061] Step b) above is the process of compounding the raw materials. The mixing ratio of peanuts, camellia seeds, and rapeseed is 100:(70-90):(10-30). This ratio not only helps to improve the nutritional completeness and taste, but also helps to generate more antioxidants during the pressing process. Preferably, the mixing ratio of peanuts, camellia seeds, and rapeseed is 100:(75-80):(20-25).

[0062] Step c) above is the mixed pressing step. Compared to the traditional method of first pressing out individual oils separately and then blending them, this step uses a one-time mixed pressing method. The pre-mixed raw materials are mixed and then fed into the press for mixed pressing. Compared to the traditional method, this improves oil extraction efficiency and prolongs the interaction time between different raw materials, increasing the contact surface area and promoting the formation of more compounds with antioxidant properties. Step c) yields a compound vegetable oil.

[0063] To improve the quality of the oil, step c) above preferably includes a step of refining the mechanically pressed compound vegetable oil, wherein the oil refining includes degumming, dehydration, decolorization and deodorization.

[0064] Accordingly, another embodiment of the present invention also provides a compound vegetable oil, which is prepared according to any one of the methods described above.

[0065] The method for preparing the compound vegetable oil provided in this invention has the following advantages:

[0066] This preparation method uses peanuts, camellia seeds, and rapeseed as raw materials, giving the edible oil higher nutritional value and a harmonious taste. The pressing process employs mixed pressing, which, compared to traditional methods, improves oil extraction efficiency and extends the interaction time between different raw materials, increasing the contact surface area and promoting the formation of more compounds with antioxidant properties. This results in a final compound oil with superior freshness and the ability to maintain its quality for a longer period under normal storage conditions.

[0067] The inventors of this application have discovered the following problem with preparing compound oils using existing presses according to the above method: the quality of the finished compound oil is unstable. Further research by the inventors revealed that the main reason for this problem is uneven material mixing, resulting in differences in contact time and contact area between different seed raw materials even with the same raw material ratio. Therefore, another embodiment of this invention provides a compound oil press, which includes a feeding unit and a pressing unit. Please see below. Figure 1 and Figure 2 The feeding unit includes: a support platform 1, a mixing mechanism, and a vibrating conveying mechanism;

[0068] The mixing mechanism includes: a feeding base 2 and a stirring screw; please refer to Figure 3 The feeding base 2 is installed on the support platform 1, and it includes, from top to bottom, a guide section, a mixing section, and a support section. The guide section includes a pair of guide baffles 21 arranged opposite each other in the vertical direction, forming a feeding area between the guide baffles 21. The mixing section forms a cylindrical mixing space 22 inside, with the top of the mixing section connected to the feeding area and a discharge port at the bottom. The stirring screw is arranged coaxially with the mixing space 22. The support section includes a pair of opposite support legs 23, with the bottom of the support legs 23 installed on the support platform 1. The support platform 1 has a strip-shaped notch, which is arranged vertically opposite to the feed port of the pressing unit.

[0069] The vibrating feeding mechanism includes: a drive unit, a lifting plate 31, and a feeding assembly;

[0070] The material conveying assembly includes: a material conveying pipe group and several feed hoppers 33. The material conveying pipe group has several material conveying pipes 32 arranged side by side along the direction of the discharge port. Each material conveying pipe 32 is arranged vertically. Please refer to [link to relevant documentation]. Figure 4 Each conveying pipe 32 is provided with a conveying inlet 321, and several feeding hoppers 33 are respectively installed on several conveying pipes 32. The hopper outlet of the feeding hopper 33 is connected to the corresponding conveying inlet 321 of the conveying pipe 32. The upper end of the lifting plate 31 is connected to the driving unit and moves up and down along the guide baffle 21 under the action of the driving unit. One side of the conveying pipe group is fixed to the lifting plate 31, and the lower end is located in the feeding area and moves up and down along the guide baffle 21.

[0071] In the aforementioned compound oil press, the feeding unit can pre-mix different raw materials to ensure uniform distribution of different materials and prevent clogging of the pressing unit. In the feeding unit, the support platform 1 provides stable support for the mixing mechanism and the vibrating conveying mechanism. The vibrating conveying mechanism is used to simultaneously feed different materials, and the mixing mechanism is used to thoroughly mix the different materials.

[0072] The working process of the compound oil press provided in this embodiment is as follows:

[0073] Different seed raw materials are fed into the corresponding conveying pipes 32 through different feed hoppers 33 according to a preset mixing ratio. The lifting plate 31 drives the conveying component to make lifting and reciprocating motions under the action of the drive unit, achieving a lifting and shaking effect. This allows different seed raw materials to be transported downwards quickly without causing blockage of the conveying pipes 32.

[0074] Raw materials from different conveying pipes 32 fall into the mixing space 22, and under the action of the stirring screw, the different raw materials are fully mixed and then enter the pressing unit for mixing and pressing under the action of gravity through the discharge port and the strip notch.

[0075] The aforementioned drive unit is used to drive the lifting plate 31 to perform lifting and reciprocating motion. Specifically, it can be a lifting cylinder or other physical mechanism. Preferably, the drive unit includes: a first motor 34, a crank-slider mechanism, and a guide bracket 35; the first motor 34 is connected to the axle of the crank wheel of the crank-slider mechanism, and the upper end of the lifting plate 31 is connected to the connecting rod of the crank-slider mechanism; the guide bracket 35 is installed on the support platform 1, and it is provided with a track in the vertical direction, and the lifting plate 31 performs lifting and reciprocating motion along the track.

[0076] The compound oil press provided in this embodiment is used to implement the above-mentioned method for preparing compound vegetable oil. Therefore, the above-mentioned conveying pipe assembly preferably has at least three conveying pipes 32. The bottom surface of the feed hopper 33 is formed with an inclined surface that slopes downward toward the hopper outlet, thereby facilitating the automatic falling of materials into the conveying inlet 321 under the action of gravity. Preferably, the above-mentioned feeding unit also includes a premixing mechanism, which includes: a mixing hopper 41, a spiral blade 42, and a second motor 43. The mixing hopper 41 is installed on the support platform 1, and the spiral blade 42 is disposed inside the mixing hopper 41. The second motor 43 is connected to the rotating shaft at one end of the spiral blade 42 and is used to drive the spiral blade 42 to rotate. The function of the premixing mechanism is that when the number of conveying pipes 32 is less than the number of raw materials, some raw materials can be mixed by the premixing mechanism before being fed into a certain feed hopper 33.

[0077] The compound oil press provided in this embodiment, by setting the aforementioned feeding unit, enables different seed raw material feeding units to premix different raw materials, ensuring uniform distribution of different materials and guaranteeing consistency in contact time and contact area between different materials during the mixing and pressing process. Furthermore, because the materials are mixed uniformly, it also avoids the agglomeration and blockage of the feed inlet and pressing unit by small-volume materials.

[0078] Accordingly, the present invention also provides an industrial production method for compound oils, comprising the following steps:

[0079] d) Raw material selection: Select peanuts, camellia seeds and rapeseed produced in the current year, and remove shriveled, moldy, insect-damaged and spoiled raw materials;

[0080] e) The peanuts, camellia seeds, and rapeseed obtained in step d) are respectively fed into different feed hoppers 33 of the compound oil press described in claim 6 in a ratio of 100:(70-90):(10-30). After being mixed by the feeding unit, they enter the pressing unit for pressing to obtain compound oil.

[0081] As can be seen from the above, this method has the advantages of high operating efficiency and good antioxidant properties of the compound oil product.

[0082] The technical solution of the present invention will be further described below with reference to specific embodiments:

[0083] Example 1

[0084] S1. Select raw materials: Select peanuts, camellia seeds and rapeseed produced in the current year, and remove shriveled, moldy, insect-damaged and spoiled raw materials.

[0085] S2. Peanut roasting: Place peanuts in the oven, set the top and bottom heat to 120-150℃, and roast for 20-30 minutes until the peanuts are dry and have a distinct aroma. Set aside for later use.

[0086] S3. Raw material compounding: Place the different raw materials in a ratio of 100:75:25 respectively. Figure 1 The different feed hoppers of the compound oil press shown use a feeding unit to mix and stir different kinds of raw materials evenly before sending them to the pressing unit for pressing.

[0087] S4. Oil Refining: Impurities and moisture in the oil are removed through degumming and dehydration. Then, decolorization and deodorization are carried out to remove pigments and odors from the oil, finally yielding a compound oil.

[0088] Examples 2 to 5

[0089] The only difference from Example 1 is the mixing ratio of peanuts, camellia seeds, and rapeseed, as detailed below:

[0090] Example 2: 100g peanuts, 80g camellia seeds, 20g rapeseed;

[0091] Example 3: 100g peanuts, 70g camellia seeds, 30g rapeseed;

[0092] Example 4: 100g peanuts, 85g camellia seeds, 15g rapeseed;

[0093] Example 5: 100g peanuts, 90g camellia seeds, 10g rapeseed.

[0094] Comparative Example 1

[0095] Peanuts were selected and roasted according to S1 and S2 in Example 1, and the peanuts were placed in... Figure 1 The compound oil press shown has a feed hopper 33 for pressing. The oil is refined according to step S4 in Example 1 to obtain peanut oil.

[0096] Comparative Example 2

[0097] Camellia seeds were selected according to S1 in Example 1, and the camellia seeds were placed... Figure 1 The compound oil press shown uses a feed hopper 33 for pressing. The oil is refined according to step S4 in Example 1 to obtain camellia seed oil.

[0098] Comparative Example 3

[0099] Rapeseed was selected according to S1 in Example 1, and the rapeseed was placed in... Figure 1 The compound oil press shown has a feed hopper 33 for pressing. The oil is refined according to step S4 in Example 1 to obtain rapeseed oil.

[0100] Comparative Example 4

[0101] Peanut oil from Comparative Example 1, camellia seed oil from Comparative Example 2, and rapeseed oil from Comparative Example 3 were mixed in a ratio of 100:75:25 to obtain blended oil.

[0102] The vegetable oils from Examples 1-5 and Comparative Examples 1-4 were subjected to oil and fat index determination. The determined indexes included acid value, peroxide value, antioxidant capacity, and fatty acid composition. By measuring these indexes, the quality and stability of the compound oils could be evaluated.

[0103] [Acid Value Determination]

[0104] According to GB 5009.229-2016 "National Food Safety Standard - Determination of Acid Value in Food", the acid value of oils was determined using the acid-base titration method. 2.5g of the oil sample was dissolved in 75mL of organic solvent (ether-isopropanol mixture, ether:isopropanol = 1:1) to form a sample solution. The free fatty acids in the sample solution were then neutralized and titrated with 0.1mol / L sodium hydroxide standard titration solution. The titration endpoint was determined by the corresponding color change of the indicator. Finally, the acid value of the oil sample was calculated based on the volume of standard titration solution consumed at the titration endpoint. The final acid value reflects the content of free fatty acids in the oil.

[0105] The measurement results are as follows Figure 5As shown in the figure, the acid values ​​of all nine oil groups are below 4 mg / g, meeting the standards for edible oils (standard acid values ​​for edible oils: peanut oil, rapeseed oil, and camellia oil ≤ 4 mg / g). The data from the oils extracted from the compound raw materials prepared in Examples 1 to 5 show an overall upward trend. Based on Comparative Examples 1, 2, and 3, it can be inferred that the peanut proportion remained constant, while the camellia seed proportion increased and the rapeseed proportion decreased. The acid value of Comparative Example 2 was higher than that of Comparative Example 3, leading to an increasing trend in the acid value of the oils extracted from the compound raw materials. A comparison between Example 1 and Comparative Example 4 reveals that compound oilseed extraction can improve the freshness of blended oils, reduce rancidity, and enhance the stability of compound oils.

[0106] Peroxide value determination

[0107] According to GB 5009.227—2016 "National Food Safety Standard - Determination of Peroxide Value in Food", the peroxide value of oils was determined using the iodine titration method. A 2g oil sample was dissolved in 30mL of organic solvent (a mixture of chloroform and glacial acetic acid, chloroform:glacial acetic acid = 2:3). 1.00mL of saturated potassium iodide solution was accurately added, the bottle was tightly capped, and gently shaken for 0.5min. The solution was then placed in the dark for 3min. 100mL of water was added, and the mixture was shaken well. Immediately afterward, the precipitated iodine was titrated with 0.01mol / L sodium thiosulfate standard solution. When the solution turned pale yellow, 1mL of starch indicator was added, and titration continued while vigorously shaking until the blue color disappeared, marking the endpoint. Finally, the peroxide value of the oil sample was calculated based on the volume of standard titration solution consumed at the titration endpoint. The degree of oxidation of the oil was assessed by determining the peroxide content in the sample. This method can characterize the freshness and oxidative stability of oils.

[0108] The measurement results are as follows Figure 6 As shown in the figure, the peroxide values ​​of all nine oil groups were below 12 meq / kg, meeting the standard requirements for edible oils (standard peroxide values ​​for edible oils: peanut oil ≤ 20 meq / kg; rapeseed oil and camellia oil ≤ 12 meq / kg). The peroxide values ​​of the oil groups in the example groups were all lower than those in comparative examples 1, 2, and 3, indicating that the compound oils exhibited a lower degree of oxidative degradation compared to pure peanut oil, pure camellia oil, and pure tea seed oil. This suggests that the antioxidant properties of the compound oils were significantly improved. Compared to comparative example 4, examples 1, 2, and 4 showed better performance in terms of antioxidant properties, but the peroxide values ​​of examples 3 and 5 were higher than those in comparative example 4. This demonstrates that selecting suitable compound raw materials for oil extraction can better characterize freshness and increase oxidative stability, thereby improving the stability of the compound oils.

[0109] [Antioxidant Activity Assay]

[0110] ① DPPH free radical scavenging ability: DPPH (2,2-diphenyl-1-picrazine) is a free radical that reflects the antioxidant capacity of oils and fats. The general method involves reacting DPPH with an oil sample and assessing the antioxidant capacity by measuring the change in its absorption peak. ② ABTS free radical scavenging ability: The ABTS+ (2,2'-diaminobis(3-ethylbenzothiazoline)) assay for oils and fats can be used to assess their antioxidant capacity. This method is mainly based on the elimination reaction of ABTS free radicals to determine the oil's ability to scavenge free radicals.

[0111] DPPH scavenging ability: Take 2 mL of different sample solutions into a test tube, add 2 mL of 0.2 mmol / L DPPH solution (shake thoroughly, centrifuge at 4000 rpm for 6 min, let stand for 30 min, zero the sample with anhydrous ethanol as the reference group, and measure the absorbance at 517 nm. Calculate the scavenging ability according to formula (1):

[0112] DPPH free radical scavenging capacity = [1-(A S -A C ) / A0]×100%(1)

[0113] AS represents the absorbance of the experimental group; AC represents the absorbance of the control group with anhydrous ethanol instead of DPPH solution; and A0 represents the absorbance of the blank group with anhydrous ethanol instead of sample solution.

[0114] ABTS+ scavenging capacity: Take 2 mL of ABTS stock solution (7.4 mmol / L, 101.5 mg dissolved in 25 mL of water) and mix with 2 mL of K2S2O8 (2.6 mmol / L, 35.1 mg dissolved in 50 mL of water), and let stand at room temperature for 14 h. Dilute 0.5 mL of ABTS working solution with 95% ethanol, and the absorbance at 734 nm at room temperature should be 0.700 ± 0.035. Mix 2.0 mL of ABTS working solution with 1 mL of different sample solutions, let stand at room temperature for 20 min, and then measure the absorbance at 734 nm (zero with distilled water). Calculate the ABTS+ scavenging capacity according to formula (2).

[0115] ABTS+ free radical scavenging ability = [1-(A S -A C ) / A0]×100%(2)

[0116] AS represents the absorbance of the experimental group; AC represents the absorbance of the control group with anhydrous ethanol instead of DPPH solution; and A0 represents the absorbance of the blank group with anhydrous ethanol instead of sample solution.

[0117] The measurement results are as follows Figure 7 and Figure 8As shown in the figure, the DPPH and ABTS+ free radical scavenging rates of the oils in the Example Group were higher than those in Comparative Examples 1, 2, and 3. This means that the oils extracted from the compound raw materials had higher scavenging rates of both free radicals than pure vegetable oils, and the higher DPPH and ABTS+ free radical scavenging rates indicated that the samples had stronger antioxidant capacity. Furthermore, compared to Comparative Example 4, the compound oils in the Example Group had higher scavenging rates of both free radicals, demonstrating that the oils extracted from the compound raw materials had stronger antioxidant capacity than blended oils. Examples 1 and 2 showed the best results, further illustrating that compound oil extraction can improve the antioxidant properties of compound oils.

[0118] Fatty acid determination

[0119] S1. Sample Weighing: Weigh 0.1g to 10g of a homogeneous sample (accurate to 0.1mg, containing approximately 100mg to 200mg of fat) into a 250mL flat-bottomed flask. Add approximately 100mg of pyrogallol, a few boiling chips, 2mL of 95% ethanol, and 4mL of water. Mix well. Accurately add 2.0mL of glycerol undecanoate tri-internal standard solution.

[0120] S2. Sample hydrolysis: Acid hydrolysis method: Add 10 mL of hydrochloric acid solution and mix well. Place the flask in a water bath at 70℃~80℃ for 40 min. Shake the flask every 10 min to mix the particles adhering to the flask wall into the solution. After hydrolysis is complete, remove the flask and cool it to room temperature.

[0121] S3. Fat Extraction: After hydrolysis, add 10 mL of 95% ethanol and mix well. Transfer the hydrolysate from the flask to a separatory funnel, rinse the flask and stopper with 50 mL of a mixture of diethyl ether and petroleum ether, and add the rinse solution to the separatory funnel. Cover the funnel. Shake for 5 min; let stand for 10 min. Collect the ether extract in a 250 mL flask. Repeat the above steps to extract the hydrolysate 3 times. Finally, rinse the separatory funnel with a mixture of diethyl ether and petroleum ether and collect the extract in a 250 mL flask. Concentrate to dryness using a rotary evaporator; the residue is the fat extract.

[0122] S4. Saponification of fats and methyl esterification of fatty acids: Add 8 mL of 2% sodium hydroxide methanol solution to the fat extract, connect a reflux condenser, and reflux in a water bath at 80℃±1℃ until the oil droplets disappear. Add 7 mL of 15% trifluoride methanol solution from the top of the reflux condenser, and continue reflux in a water bath at 80℃±1℃ for 2 min. Rinse the reflux condenser with a small amount of water. Stop heating, remove the flask from the water bath, and quickly cool to room temperature.

[0123] Accurately add 10 mL to 30 mL of n-heptane, shake for 2 min, then add saturated sodium chloride aqueous solution and allow to stand for separation. Pipette approximately 5 mL of the upper n-heptane extract into a 25 mL test tube, add approximately 3 g to 5 g of anhydrous sodium sulfate, shake for 1 min, let stand for 5 min, and then transfer the upper layer solution into a sample vial for analysis.

[0124] S5. Determination of chromatographic reference conditions: Inject single fatty acid methyl ester standard solutions and mixed fatty acid methyl ester standard solutions into the gas chromatograph and perform qualitative analysis on the chromatographic peaks.

[0125] a) Capillary column: polydicyandipropylsiloxane strongly polar stationary phase, column length 100m, inner diameter 0.25mm, film thickness 0.2μm.

[0126] b) Injector temperature: 270℃.

[0127] c) Detector temperature: 280℃.

[0128] d) Programmed temperature rise: initial temperature 100℃, duration 13 min

[0129] 100℃~180℃, heating rate 10℃ / min, hold for 6min;

[0130] 180℃~200℃, mixing rate 1℃ / min, hold for 20min;

[0131] 200℃~230℃, heating rate 4℃ / min, hold for 10.5min.

[0132] e) Carrier gas: Nitrogen.

[0133] f) Split ratio: 100:1.

[0134] g) Injection volume: 1.0 μL.

[0135] h) The detection conditions should meet the following requirements: theoretical plate number (n) at least 2000 / m, and resolution (R) at least 1.25.

[0136] Under the above chromatographic conditions, the fatty acid standard solution and sample solution were injected separately into the gas chromatograph, and quantification was performed based on peak area. The fatty acid composition analysis is shown in Table 1.

[0137] Table 1. Fatty acid composition of the vegetable oils prepared in the Examples and Comparative Examples

[0138]

[0139]

[0140] Analysis of fatty acid determination showed that the composition of unsaturated fatty acids in the oil extracted from the compound raw materials was improved compared with Comparative Examples 1, 2, and 3, and the nutritional value distribution was more reasonable. Furthermore, the linoleic acid content in Comparative Example 4 was lower than that in the oil extracted from the compound raw materials, and Examples 1 and 2 performed better, indicating that the oil extracted from the compound raw materials could retain higher nutritional value than blended oils. By comparing the proportion of erucic acid, it was found that peanut oil and camellia oil contained extremely low amounts of erucic acid, while rapeseed oil had a relatively high erucic acid content. Moreover, the proportion of erucic acid in the oil extracted from the compound raw materials was lower than that in Comparative Example 4, indicating that the oil extracted from the compound raw materials could improve the instability of blended oils to a certain extent and enhance the nutritional and health value of the compound oils.

[0141] In summary, the compound oil pressing method and compound press provided by the invention can improve the continuity of pressing, significantly improve the oil pressing efficiency, and facilitate disassembly and assembly. The compound oil obtained in the embodiments has significantly improved antioxidant capacity compared with the comparative example, and its freshness is better. In terms of nutritional value, the oil extracted from the compound raw materials shows a more reasonable nutrient distribution than pure vegetable oil, and compared with blended oil, it can also improve instability to a certain extent.

[0142] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A compound oil press comprising a feed unit and a pressing unit, characterized in that, The feeding unit includes: a support platform, a mixing mechanism, and a vibrating conveying mechanism; The mixing mechanism includes a feeding base and a stirring screw. The feeding base is installed on a support platform and, from top to bottom, includes a guide section, a mixing section, and a support section. The guide section includes a pair of guide baffles arranged vertically opposite each other, forming a feeding area between the guide baffles. The mixing section forms a cylindrical mixing space inside, with its top connected to the feeding area and its bottom having a discharge port. The stirring screw is disposed within the mixing space and arranged coaxially with it. The support section includes a pair of opposite support legs, the bottom of which is mounted on the support platform. The support platform has a strip-shaped notch, which is vertically opposite to the discharge port and the feed port of the pressing unit. The vibrating feeding mechanism includes: a drive unit, a lifting plate, and a feeding assembly; The material conveying assembly includes: a material conveying pipe group and several feeding hoppers. The material conveying pipe group has several material conveying pipes arranged in parallel along the direction of the discharge port. Each material conveying pipe is arranged vertically and has a material inlet. Several feeding hoppers are respectively installed on several material conveying pipes, and the hopper outlets of the feeding hoppers are connected to the material inlets of the corresponding material conveying pipes. The upper end of the lifting plate is connected to the drive unit and moves up and down along the guide baffle under the action of the drive unit. One side of the material conveying pipe group is fixed to the lifting plate, and the lower end is located in the feeding area and moves up and down along the guide baffle.

2. The compound oil press according to claim 1, characterized in that The drive unit includes: a first motor, a crank-slider mechanism, and a guide bracket; the first motor is connected to the axle of the crank wheel of the crank-slider mechanism, and the upper end of the lifting plate is connected to the connecting rod of the crank-slider mechanism; the guide bracket is installed on a support platform, and a track is provided along the vertical direction, and the lifting plate performs a reciprocating lifting motion along the track.

3. The compound oil press according to claim 1, characterized in that, The material conveying pipe assembly is provided with at least three material conveying pipes; the bottom surface of the feed hopper is formed with an inclined surface that slopes downward toward the hopper outlet.

4. The compound oil press according to claim 1, characterized in that, The feeding unit also includes a premixing mechanism, which includes a mixing hopper, a spiral blade, and a second motor. The mixing hopper is mounted on a support platform, and the spiral blade is disposed inside the mixing hopper. The second motor is connected to a rotating shaft at one end of the spiral blade and is used to drive the spiral blade to rotate.

5. An industrial production method for a compound oil, characterized in that, Including the following steps: d) Raw material selection: Select peanuts, camellia seeds and rapeseed produced in the current year, and remove shriveled, moldy, insect-damaged and spoiled raw materials; e) The peanuts, camellia seeds, and rapeseed obtained in step d) are respectively fed into different feed hoppers of the compound oil press described in claim 1 in a ratio of 100:(70~90):(10~30). After being mixed by the feeding unit, they enter the pressing unit for pressing to obtain compound oil.

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