Method of producing oil

Abstract

The present invention provides a method for producing oil that allows for the simple and reliable acquisition of oil from an emulsion without degrading the quality of the oil. [Solution] The method for producing oil comprises a containment step, an addition step, and a first removal step. In the containment step, an emulsion containing oil, water, and a third component other than oil and water is contained in a container 10. In the addition step, at least one of a first addition step, in which a low-viscosity liquid is added to the emulsion, and a second addition step, in which an alkaline aqueous solution is added to the emulsion, is performed before, during, or simultaneously with the containment step. In the first removal step, after the containment step and the addition step, water is removed from the emulsion by reducing the pressure inside the container 10 using a water ejector 50.

Description

Technical Field

[0001] The present disclosure relates to a method for producing oil, and more specifically to a method for producing oil from an emulsion.

Background Art

[0002] In recent years, discarded food waste containing oil such as mayonnaise, butter and cream has been collected, and oil obtained by separation from such food waste has been recycled as feed raw materials and the like.

[0003] Patent Document 1 discloses a method for separating and recovering oil and fat contained in oil-containing food and / or food residue. In this method, the oil-containing food and / or food residue is treated in the presence of 100 to 500 parts by mass of water relative to a total of 100 parts by mass of components other than water contained in the food and / or food residue, and subjected to heating and pressurizing treatment at a temperature of 120°C or higher and lower than 200°C and a pressure of 0.2 MPa or higher and lower than 1.5 MPa. According to the technology of Patent Document 1, by performing the heating and pressurizing treatment under the above conditions, the emulsion in which oil and fat are emulsified and dispersed in an aqueous phase is decomposed and separated into an oil phase and an aqueous phase, whereby oil and fat and the like can be separated and recovered.

Prior Art Literature

Patent Literature

[0004]

Patent Literature 1

Summary of the Invention

Problem to be Solved by the Invention

[0005] However, the above conventional method involves complicated processes and requires high-temperature and high-pressure treatment, so there is a possibility that the quality of the obtained oil is degraded.

[0006] The object of this disclosure is to provide a method for producing oil that allows oil to be obtained simply and reliably from an emulsion without degrading the quality of the oil. [Means for solving the problem]

[0007] A method for producing oil according to one aspect of the present disclosure comprises a containment step of containing an emulsion containing oil, water, and a third component other than the oil and water in a container; an addition step of performing at least one of a first addition step of adding a low-viscosity liquid to the emulsion and a second addition step of adding an alkaline aqueous solution to the emulsion before, during, or simultaneously with the containment step; and a first removal step of removing the water from the emulsion by reducing the pressure inside the container using a water ejector after the containment step and the addition step. [Effects of the Invention]

[0008] According to this disclosure, oil can be obtained from an emulsion in a simple and reliable manner without degrading the quality of the oil. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic diagram showing an example of a manufacturing system used in the method for producing oil according to this disclosure. [Figure 2] Figure 2 is a flowchart showing the flow of each step in the method for producing oil according to the first embodiment of this disclosure. [Figure 3] Figure 3 is a flowchart showing the flow of each step in the method for producing oil according to the second embodiment of this disclosure. [Figure 4] Figure 4 is a flowchart showing the flow of each step in the method for producing oil according to the third embodiment of this disclosure. [Modes for carrying out the invention]

[0010] 1. Overview The following describes the method for producing oil in the embodiments of this disclosure. Note that the following embodiments are only a part of the various embodiments of this disclosure. The following embodiments can be modified in various ways depending on the design, as long as the objectives of this disclosure are achieved.

[0011] Many emulsions, which are raw materials for recovering or producing oil, have low fluidity and are acidic, such as those containing acetic acid, as seen in discarded mayonnaise. When producing oil from such emulsions, it is necessary to consider the production method taking into account the low fluidity and acidity of the emulsion. The inventors have found that even with such emulsions, by performing a specific treatment on the emulsion and employing a specific vacuum means, water can be efficiently removed from the emulsion, thereby solving the above problem and enabling the simple and reliable production of oil without degrading the quality of the oil. This invention has now been completed.

[0012] The method for producing oil according to this embodiment (hereinafter also referred to as the production method (S)) comprises a containment step (hereinafter also referred to as the containment step (K)), an addition step (hereinafter also referred to as the addition step (L)), and a first removal step (hereinafter also referred to as the removal step (M1)).

[0013] In the containment step (K), an emulsion (hereinafter also called emulsion (A)) containing oil (hereinafter also called oil (X)), water (hereinafter also called water (Y)), and a third component other than oil (X) and water (Y) (hereinafter also called component (Z)) is contained in the container 10.

[0014] In the addition step (L), at least one of the first addition step (hereinafter also referred to as addition step (L1)) and the second addition step (hereinafter also referred to as addition step (L2)) is performed before, during, or simultaneously with the containment step (K). In the addition step (L1), a low-viscosity liquid (hereinafter also referred to as low-viscosity liquid (P)) is added to the emulsion (A). In the addition step (L2), an alkaline aqueous solution (hereinafter also referred to as alkaline aqueous solution (Q)) is added to the emulsion (A).

[0015] In the removal step (M1), after the containment step (K) and the addition step (L), water (Y) is removed from the emulsion (A) by reducing the pressure inside the container 10 using a water ejector 50.

[0016] According to the manufacturing method (S) of the present disclosure, by including these steps, oil can be obtained simply and reliably from the emulsion without degrading the quality of the oil. The reason why the manufacturing method (S) achieves the above effect by having the above configuration can be inferred, for example, as follows. That is, the manufacturing method (S) employs a water ejector 50 as a means of reducing pressure, which can achieve a high degree of reduced pressure and effectively remove water (Y) removed from the emulsion (A) from the system, thereby enabling efficient removal of water (Y) from the emulsion (A) at a relatively low temperature. Furthermore, even if the raw material emulsion (A) is of low fluidity, such as mayonnaise, by including an addition step (L1) to add a low viscosity liquid (P), the emulsion (A) can be made to have appropriate fluidity, making it easier to transfer the emulsion (A) and making the containment step (K) easier, and also enabling more efficient removal of water (Y) in the removal step (M1). Furthermore, even if the raw material emulsion (A) contains acid, it can be made neutral by including an addition step (L2) to add an alkaline aqueous solution (Q), and in the removal step (M1), it becomes possible to use a manufacturing system 1 that includes a metal water ejector 50 that is corrosive to acid. In addition, by including this addition step (L2), the obtained component (Z) can be recycled by making the emulsion (A) neutral. As a result, it is considered that oil (X) can be obtained from emulsion (A) simply, reliably, and without degrading the quality of the oil according to the manufacturing method (S).

[0017] 2.Details <Method for producing oil> The manufacturing method (S) of this embodiment will be described below with reference to the drawings. Figure 1 is a diagram showing an example of production system 1 used in production method (S).

[0018] The production system 1 shown in Figure 1 includes a container 10, a water ejector 50, and a cooler 60. Production system 1 further includes a raw material tank 20 for supplying emulsion (A) which is a production raw material, an oil tank 31 for obtaining oil (X) which is one separated product, a water tank 32 for obtaining water (Y), a third component tank 33 for obtaining component (Z), a liquid tank 41 for supplying low-viscosity liquid (P) which is an additive liquid, and an alkali tank 42 for supplying alkaline aqueous solution (Q).

[0019] Production method (S) includes a containing step (K), an adding step (L), and a removing step (M1). In the adding step (L), at least one of an adding step (L1) and an adding step (L2) is performed before, after, or simultaneously with the containing step (K). The removing step (M1) is performed after the containing step (K) and the adding step (L).

[0020] Production method (S) may further include a second removing step (hereinafter also referred to as removing step (M2)) for removing component (Z) (third component) from emulsion (A) after the removing step (M1) (first removing step). Each step is described below.

[0021] [Containing Step] In the containing step (K), emulsion (A) containing oil (X), water (Y), and component (Z) is contained in the container 10.

[0022] (Emulsion) The "emulsion", also referred to as an emulsion, refers to a system of two immiscible liquid phases, namely an oil (X) phase and a water (Y) phase, in which one phase is dispersed in the other phase in the form of fine particles.

[0023] "Water" refers to water (H2O). "Oil" refers to a liquid component that is incompatible with water (Y). "Incompatible with water" means that when mixed with water (Y) at 25°C, the oil (X) does not mix with water (Y), and that water (Y) and oil (X) exist as two separate liquid phases. The oil (X) may consist of one or more components.

[0024] Examples of emulsions (A) include oil-water emulsions (o / w type (oil-in-water) emulsions) where the continuous phase is water (Y), and water-oil emulsions (w / o type (water-in-oil) emulsions) where the continuous phase is oil (X).

[0025] Examples of oil-water emulsions include mayonnaise, mayonnaise-like condiments, dressings, sauces, dips, and creams such as fresh cream, buttercream, and fat spreads. Examples of water-oil emulsions include butter, margarine, oily sauces, and creams such as sugar cream.

[0026] Examples of oils (X) include vegetable oils such as rapeseed oil, soybean oil, palm oil, palm kernel oil, coconut oil, corn oil, cottonseed oil, rice oil, sunflower oil, and safflower oil; animal oils such as beef tallow, lard, milk fat, fish oil, and whale oil; and processed oils obtained by subjecting these to at least one of hydrogenation and transesterification.

[0027] Emulsion (A) contains component (Z) (third component). Component (Z) is a component other than oil (X) and water (Y), and acts as an emulsifier, etc., to disperse the oil (X) and water (Y) and form emulsion (A). Component (Z) is usually solid or liquid. Examples of component (Z) include carboxylic acids such as acetic acid, monoglycerides, proteins such as lecithin, fruit juice, egg yolk, egg white, protein hydrolysates, salt, sugar, honey, spices, seasonings, etc. Mayonnaise as emulsion (A) contains acetic acid and egg yolk as component (Z). Emulsion (A) may also contain other components other than oil (X), water (Y), and component (Z).

[0028] The emulsion (A) used as a raw material for this manufacturing process is preferably derived from food waste. By using food waste as emulsion (A), it is possible to contribute to the collection and recycling of food waste.

[0029] (container) The container 10 can be any hollow structure that can contain the emulsion (A) in the containment step (K) and whose interior can be depressurized using the water ejector 50 in the removal step (M1).

[0030] Examples of the container 10's shape include a hollow cylindrical shape, a spherical shape, a rectangular tube shape, a rectangular parallelepiped shape, a cuboid shape, and so on. The internal volume of container 10 is, for example, 0.1 m³. 3 More than 10m 3 The following applies: Examples of materials for the container 10 include polyethylene terephthalate (PET), polystyrene, and other resins, as well as metals such as aluminum and stainless steel.

[0031] The lower surface of the container 10 may have an opening that can be opened and closed, for example, to extract component (Z) or a mixture of oil (X) and component (Z) after the removal step (M1).

[0032] The container 10 is typically equipped with stirring blades 11 inside (see Figure 1). The shape of the stirring blades 11 is not particularly limited, as long as it can stir the emulsion (A) contained in the container 10, but examples include propeller type, fan type, U-shaped, cross-shaped, dragonfly type, butterfly type, anchor type, turbine type, ribbon type, etc. The axis direction of the stirring blades 11 may be horizontal, vertical, or any other direction, but from the viewpoint of stirring efficiency, it is preferably horizontal.

[0033] The container 10 preferably has a heating means for heating the contained emulsion (A) in the removal step (M1). Examples of heating means include a heater and a jacket through which a heat transfer medium passes.

[0034] (Storage process) The containment process (K) is specifically carried out by, for example, transferring the emulsion (A), which is the raw material for production, that has been placed in the raw material tank 20 into the container 10 using a pump (not shown), or by using a difference in height, pressure, etc. The containment process (K) may also be carried out by transferring the emulsion (A) that has been placed in a tank other than the raw material tank 20 into the container 10.

[0035] [Addition process] In the addition step (L), at least one of the addition step (L1) and the addition step (L2) is performed before, during, or simultaneously with the containment step (K).

[0036] (Addition process (L1)) In the addition step (L1), a low-viscosity liquid (P) is added to the emulsion (A).

[0037] (Low viscosity liquid) A "low-viscosity liquid" refers to a liquid with a viscosity of 1 Pa·s or less at 25°C, preferably a liquid with a viscosity of 0.01 mPa·s or more and 100 mPa·s or less.

[0038] Examples of low-viscosity liquids (P) include water, aqueous solutions of salts such as sodium chloride, and organic solvents such as ethanol. Of these, water is preferred. Alternatively, water (Y) obtained in the removal step (M1) and oil (X) obtained in the removal step (M2) can also be used as the low-viscosity liquid (P).

[0039] The temperature of the low-viscosity liquid (P) is usually greater than 0°C and less than 100°C. From the viewpoint of facilitating mixing with the emulsion (A), which is the raw material for production, the temperature of the low-viscosity liquid (P) is preferably 20°C or higher, more preferably 50°C or higher, and even more preferably 80°C or higher. For example, the temperature of the low-viscosity liquid (P) is 95°C or lower.

[0040] The amount of low-viscosity liquid (P) to be added is, for example, 10 to 50 parts by mass, preferably 15 to 40 parts by mass, and more preferably 20 to 30 parts by mass, per 100 parts by mass of emulsion (A).

[0041] The addition step (L1) can be performed before, during, or simultaneously with the containment step (K). In other words, the addition step (L1) may be performed before the containment step (K), simultaneously with the containment step (K), or after the containment step (K). Of these, it is preferable that the addition step (L1) be performed before or after the containment step (K), and more preferably before the containment step (K). Performing the addition step (L1) before the containment step (K) can increase the fluidity of the emulsion (A) in the raw material tank 20, making the containment step (K) easier to perform.

[0042] The addition step (L1) may be carried out, for example, by transferring the low-viscosity liquid (P) from the liquid tank 41 to the emulsion (A) in the raw material tank 20 using a pump (not shown) or by using a difference in elevation, pressure, etc., or by transferring the low-viscosity liquid (P) from the liquid tank 41 to the emulsion (A) contained in the container 10 by the containment step (K) using a pump (not shown) or by using a difference in elevation, pressure, etc. The addition step (L1) may also be carried out by sending the low-viscosity liquid (P) contained in a tank other than the liquid tank 41 to the raw material tank 20 or the container 10.

[0043] (Addition process (L2)) In the addition step (L2), an alkaline aqueous solution (Q) is added to the emulsion (A).

[0044] (Alkaline solution) An "alkaline aqueous solution" refers to an aqueous solution of an alkaline substance. Examples of alkaline substances include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide, and lithium hydroxide; alkaline earth metal hydroxides such as calcium hydroxide, barium hydroxide, and magnesium hydroxide; alkali metal carbonates such as sodium carbonate and potassium carbonate; alkaline earth metal carbonates such as calcium carbonate and barium carbonate; and basic compounds such as organic amine compounds and ammonia.

[0045] The concentration of the alkaline aqueous solution (Q) is, for example, 1% by mass or more and 20% by mass or less, preferably 5% by mass or more and 15% by mass or less, and more preferably 7% by mass or more and 13% by mass or less.

[0046] The emulsion (A) after the addition step (L2) is preferably neutral. The pH of the emulsion (A) after the addition step (L2) is preferably 6 to 8, and more preferably 6 to 7.

[0047] The amount of alkaline aqueous solution (Q) to be added is, for example, 1 to 5 parts by mass, preferably 1.5 to 4 parts by mass, and more preferably 2 to 3 parts by mass, per 100 parts by mass of emulsion (A).

[0048] The concentration of the added alkali relative to the emulsion (A) is, for example, 0.1% by mass or more and 0.5% by mass or less, preferably 0.15% by mass or more and 0.4% by mass or less, and more preferably 0.2% by mass or more and 0.3% by mass or less.

[0049] The addition step (L2) can be performed before, after, or simultaneously with the containment step (K). In other words, the addition step (L2) may be performed before the containment step (K), simultaneously with the containment step (K), or after the containment step (K). Of these, it is preferable that the addition step (L2) be performed before or after the containment step (K), and more preferably before the containment step (K). Performing the addition step (L2) before the containment step (K) can increase the fluidity of the emulsion (A) in the raw material tank 20, making the containment step (K) easier to perform.

[0050] The addition step (L2) may be carried out, for example, by transferring the alkaline aqueous solution (Q) from the alkali tank 42 to the emulsion (A) in the raw material tank 20 using a pump (not shown) or by using a difference in elevation, pressure, etc., or by transferring the alkaline aqueous solution (Q) from the alkali tank 42 to the emulsion (A) contained in the container 10 by the containment step (K) using a pump (not shown) or by using a difference in elevation, pressure, etc. The addition step (L2) may also be carried out by sending the alkaline aqueous solution (Q) contained in a tank other than the alkali tank 42 to the raw material tank 20 or the container 10.

[0051] If emulsion (A) is a low-fluidity substance such as mayonnaise and contains acid, it is preferable to perform both addition step (L1) and addition step (L2) as addition step (L). If emulsion (A) is a low-fluidity substance such as butter or margarine and is neutral, it is preferable to perform only addition step (L1) as addition step (L).

[0052] [First removal process] In the removal step (M1), water (Y) is removed from the emulsion (A) by reducing the pressure inside the container 10 using a water ejector 50.

[0053] (Water ejector) The water ejector 50 is a gas-liquid mixing device that creates negative pressure by supplying pressurized water (not shown) using a water circulation pump and ejecting this pressurized water to expel gas. By using the water ejector 50, the pressure (absolute pressure) inside the container 10 can be set to, for example, about 1 kPa to 10 kPa.

[0054] It is preferable to use a horizontal-jet type water ejector with a water circulation pump as the water ejector 50. A horizontal-jet type water ejector can achieve a higher degree of depressurization and a higher gas discharge capacity, so the degree of depressurization in the container 10 can be further increased.

[0055] It is preferable to use water that has been pre-cooled by a water cooling unit or the like when supplying water to the water ejector 50 with a water circulation pump. In this case, the degree of reduced pressure in the container 10 can be further increased.

[0056] (1st removal process) The removal process (M1) is performed by reducing the pressure in the container 10 by suction from the water ejector 50. This pressure reduction causes water (Y) to evaporate from the emulsion (A) in the container 10, condense in the cooler (condenser) 60, and be collected in the water tank 32.

[0057] (conditions) In the removal process (M1), it is preferable to set the pressure (degree of reduced pressure) and temperature inside the container 10 so that the water (Y) inside the container 10 reaches its boiling point. In this case, more water (Y) in the emulsion (A) can be removed more quickly, and the deterioration of the quality of the resulting oil (X) can be suppressed more effectively.

[0058] The depressurization conditions in the removal process (M1) are such that the degree of depressurization (absolute pressure) inside the container 10 is, for example, 20 kPa or less, preferably 15 kPa or less, more preferably 10 kPa or less, even more preferably 5 kPa or less, and particularly preferably 3 kPa or less, with vacuum being 0 kPa. Also, the degree of depressurization (absolute pressure) is, for example, 1 kPa or more. By setting the degree of depressurization within the above range, water (Y) can be removed more reliably from emulsion (A) in the removal process (M1). This degree of depressurization can be achieved by adjusting the performance of the water ejector 50, the speed and temperature of the water supplied by the water circulation pump, etc.

[0059] The temperature conditions in the removal step (M1) are such that the temperature of the emulsion (A) in the container 10 is, for example, above 0°C, preferably 20°C or higher, more preferably 30°C or higher, even more preferably 35°C or higher, and particularly preferably 40°C or higher. The upper limit of the temperature is, for example, 80°C or lower, preferably 70°C or lower, and more preferably 60°C or lower.

[0060] In the removal step (M1), it is preferable to stir using the stirring blade 11. Stirring makes the removal step (M1) easier to perform.

[0061] [Second removal process] In the removal step (M2), component (Z) is removed from the emulsion (A) after the removal step (M1), i.e., from the mixture of oil (X) and component (Z) obtained in the removal step (M1). This allows the oil (X) to be obtained. The removal step (M2) can be carried out by, for example, static separation, filtration, centrifugation, etc.

[0062] In the removal step (M2), it is preferable to separate the mixture of oil (X) and component (Z), which is the emulsion (A) after the removal step (M1), into supernatant oil (X) and precipitate component (Z) by allowing it to stand for a certain period of time (for example, overnight). In this way, the supernatant oil (X) can be recovered into the oil tank 31 using a pump (not shown), and the precipitate component (Z) can be recovered into the third component tank 33 using a pump (not shown), or by using a difference in height, pressure, etc.

[0063] The removal process (M2) may be carried out not only within container 10, but also by transferring the mixture of oil (X) and component (Z) in container 10 to another container after the removal process (M1), and separating the oil (X) and component (Z) in the other container.

[0064] The precipitate component (Z) is preferably further filtered, for example, by passing it through a filter cloth such as a piece of cloth. This allows for obtaining component (Z) from which more of the oil (X) has been removed. The component (Z) obtained in this way can be recycled.

[0065] [Embodiment] The manufacturing methods (S) of the first to third embodiments of this disclosure are shown below.

[0066] If emulsion (A) is a low-fluidity substance such as mayonnaise and contains acid, it is preferable to use the manufacturing method (S) of the first or second embodiment. Furthermore, if emulsion (A) is a low-fluidity substance such as butter or margarine, it is preferable to use the manufacturing method (S) of the third embodiment.

[0067] [First Embodiment] In the manufacturing method (S) of the first embodiment, as shown in Figure 2, first, before the containment step (K), an addition step (L1) and an addition step (L2) are performed, then the containment step (K) is performed, and further, after the containment step (K), a removal step (M1) is performed, and then, after the removal step (M1), a removal step (M2) is performed. Specifically, after the emulsion (A) is placed in the raw material tank 20, a low viscosity liquid (P) is added from the liquid tank 41 to the raw material tank 20 (addition step (L1)), and an alkaline aqueous solution (Q) is added from the alkali tank 42 (addition step (L2)). Next, the mixture in the raw material tank 20 is transferred and contained in the container 10 (containment step (K)). Furthermore, the water ejector 50 is activated to reduce the pressure in the container 10 and remove water (Y) (removal step (M1)). Next, by allowing the remaining material to stand, the oil (X) as the supernatant and the components (Z) as the precipitate are separated, and then the oil (X) as the supernatant and the components (Z) as the precipitate are obtained (removal step (M2)).

[0068] [Second Embodiment] In the manufacturing method (S) of the second embodiment, as shown in Figure 3, first, an addition step (L1) is performed before the containment step (K), then the containment step (K) is performed, and an addition step (L2) is performed after the containment step (K), and further, a removal step (M1) is performed after the containment step (K) and the addition step (L), and then a removal step (M2) is performed after the removal step (M1). Specifically, the emulsion (A) is placed in the raw material tank 20, and then a low viscosity liquid (P) is added to the raw material tank 20 from the liquid tank 41 (addition step (L1)). Next, the mixture in the raw material tank 20 is transferred and contained in the container 10 (containment step (K)). Next, an alkaline aqueous solution (Q) is added to the container 10 from the alkali tank 42 (addition step (L2)). Furthermore, the water ejector 50 is activated to reduce the pressure in the container 10 and remove water (Y) (removal step (M1)). Next, by allowing the remaining material to stand, the oil (X) as the supernatant and the components (Z) as the precipitate are separated, and then the oil (X) as the supernatant and the components (Z) as the precipitate are obtained (removal step (M2)).

[0069] [Third Embodiment] In the manufacturing method (S) of the third embodiment, as shown in Figure 4, first an addition step (L1) is performed before the containment step (K), then the containment step (K) is performed, and furthermore, a removal step (M1) is performed after the containment step (K), and then a removal step (M2) is performed after the removal step (M1). Specifically, the emulsion (A) is placed in the raw material tank 20, and then a low viscosity liquid (P) is added to the raw material tank 20 from the liquid tank 41 (addition step (L1)). Next, the mixture in the raw material tank 20 is transferred and contained in the container 10 (containment step (K)). Subsequently, the water ejector 50 is activated to reduce the pressure in the container 10 and remove the water (Y) (removal step (M1)). Then, by allowing the residue to stand, the oil (X) as supernatant and the components (Z) as precipitate are separated, and the oil (X) as supernatant and the components (Z) as precipitate are obtained respectively (removal step (M2)).

[0070] In the manufacturing methods (S) of the first to third embodiments, it is preferable to use, for example, water, hot water, or recovered oil (X) as the low-viscosity liquid (P) in the addition step (L1), and it is preferable to use, for example, an aqueous sodium hydroxide solution as the alkaline aqueous solution (Q) in the addition step (L2). [Examples]

[0071] The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited to the examples.

[0072] <Oil production> The oil was produced from emulsion (A) using the following procedure. [Example 1] Mayonnaise, a food waste product, was used as the raw material emulsion (A). 800 L (760 kg) of mayonnaise was placed in a raw material tank. To this, 180 L (180 kg) of hot water (80°C) as a low-viscosity liquid (P) and 20 L (22.2 kg) of an alkaline aqueous solution (10% by mass aqueous solution of sodium hydroxide) were added, and then the mixture was combined to obtain a homogeneous raw material mixture. This raw material mixture was transferred and placed in a container. The contents of this container were stirred with a stirrer, and the pressure was reduced using a water ejector to perform the removal process (M1). The removal process (M1) was carried out under the following conditions: temperature: 40-60°C, pressure (absolute pressure): 3kPa, and pressure reduction time: 3 hours and 45 minutes. After the depressurization was completed, the oil (X) was left to stand overnight, and then the supernatant oil was transferred to the oil tank. The residue was a mixture of solids, creams, and oil (X). This mixture was filtered using a cloth to separate the solid and creamy components.

[0073] [Example 2] The oil was produced in the same manner as in Example 1, except that the alkaline aqueous solution (Q) was added to the container instead of the raw material tank.

[0074] [Example 3] The oil was produced in the same manner as in Example 1, except that 180 L (162 kg) of the oil (X) obtained in Example 1 was used as the low-viscosity liquid (P) instead of 180 L of hot water (80°C).

[0075] (summary) As is clear from the above embodiments, this disclosure includes the following aspects.

[0076] The first embodiment of the method for producing oil (S) comprises a containment step (K), an addition step (L) before, during, or simultaneously with the containment step (K), and a first removal step (M1) after the containment step (K) and the addition step (L). In the containment step (K), an emulsion (A) containing oil (X), water (Y), and a third component (Z) other than oil (X) and water (Y) is contained in a container 10. In the addition step (L), at least one of a first addition step (L1) in which a low viscosity liquid (P) is added to the emulsion (A), and a second addition step (L2) in which an alkaline aqueous solution (Q) is added to the emulsion (A). In the first removal step (M1), water (Y) is removed from the emulsion (A) by reducing the pressure inside the container 10 using a water ejector 50.

[0077] According to the first embodiment, oil (X) can be obtained from emulsion (A) simply and reliably without degrading the quality of the oil (X).

[0078] In the second embodiment of the method for producing oil (S), the method further comprises a second removal step (M2) for removing a third component (Z) from the emulsion (A) after the first removal step (M1), as in the first embodiment.

[0079] According to the second embodiment, the oil (X) and the third component (Z) can be easily and reliably obtained from the emulsion (A) without degrading the quality of the oil (X).

[0080] In the third embodiment of the method for producing oil (S), in the first or second embodiment, the emulsion (A) is derived from food waste.

[0081] According to the third embodiment, oil (X) can be obtained simply and reliably from emulsion (A), which is food waste, without degrading the quality of the oil (X), thereby contributing to the collection and recycling of food waste.

[0082] In the fourth embodiment of the method for producing oil (S), in any one of the first to third embodiments, the first addition step (L1) and the second addition step (L2) are performed in the addition step (L).

[0083] According to the fourth embodiment, even with an emulsion (A) that has low fluidity, such as mayonnaise, and contains acid, oil (X) can be easily and reliably obtained from the emulsion (A) without degrading the quality of the oil (X).

[0084] In the fifth embodiment of the method for producing oil (S), in any one of the first to third embodiments, the first addition step (L1) is performed in the addition step (L).

[0085] According to the fifth embodiment, even with an emulsion (A) that has low fluidity, such as butter or margarine, oil (X) can be easily and reliably obtained from the emulsion (A) without degrading the quality of the oil (X). [Explanation of Symbols]

[0086] 1. Oil production system 10 containers 50 Water Ejectors

Claims

1. A containing step of containing an emulsion derived from food waste, which contains oil, water, and a third component other than the oil and water, in a container, An addition step is performed before, during, or simultaneously with the aforementioned containment step, which includes at least one of a first addition step in which a low-viscosity liquid is added to the emulsion, and a second addition step in which an alkaline aqueous solution is added to the emulsion. A first removal step is performed after the containment step and the addition step, by reducing the pressure inside the container using a water ejector to remove the water from the emulsion. Equipped with, A method for producing oil, wherein the amount of the low-viscosity liquid in the first addition step is 10 parts by mass or more and 50 parts by mass or less per 100 parts by mass of the emulsion.

2. A second removal step in which the third component is removed from the emulsion after the first removal step. The method for producing oil according to claim 1, further comprising

3. In the aforementioned addition process, the first addition step and the second addition step are performed. A method for producing oil according to claim 1 or 2.

4. In the aforementioned addition step, the first addition step is performed. A method for producing oil according to claim 1 or 2.

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