Method for producing edible oils and fats and use of said edible oils and fats

Abstract

Provided is a production method for obtaining an edible oil and fat that has a low trans-fatty acid content and other exceptional qualities.　This method for producing an edible oil and fat involves performing a purification treatment on an unrefined oil obtained from an oil and fat raw material, wherein: the purification treatment includes a deodorization step; and the deodorization step is performed while satisfying all of a condition 1) that the temperature is 210-220°C, a condition 2) that the degree of vacuum is greater than 2.1 Torr and no greater than 4.0 Torr, and a condition 3) that the amount of water vapor supplied to the oil and fat when the deodorization treatment is executed is at least 0.5 mass% and less than 2.5 mass%.

Description

[Technical Field]

[0001] The present invention relates to a method for producing edible oils and fats and uses of the edible oils and fats. [Background technology]

[0002] It is known that excessive intake of trans fatty acids increases the risk of heart disease. For this reason, it is preferable for edible oils and fats to have a low trans fatty acid content. According to the Consumer Affairs Agency's guidelines, if a food contains less than 0.3g of trans fatty acids per 100g, it can be labeled as trans fatty acid-free. For this reason, oils and fats with a lower trans fatty acid content are desired.

[0003] With regard to technologies for reducing the content of trans fatty acids, various conditions in the refining process of edible oils and fats have been investigated. For example, Patent Document 1 below discloses a method for producing refined rapeseed oil, which includes a deodorizing step of deodorizing rapeseed oil, in which the deodorizing step includes a contacting step of contacting rapeseed oil with steam at a temperature of 205 to 225°C and a vacuum of 300 to 800 Pa for 53 to 100 minutes, in which the upper limit of the temperature condition for the deodorizing step does not exceed 225°C, the amount of steam is 2.5 to 5.0 mass% relative to the rapeseed oil, and the refined rapeseed oil obtained after the contacting step has an α-tocopherol content of 172 ppm or more. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6348685 Summary of the Invention [Problem to be solved by the invention]

[0005] However, currently, no sufficient research has been conducted on a manufacturing method for obtaining edible oils and fats that have a low content of trans fatty acids and also have excellent other qualities such as acid value, oxidation stability, and release properties.

[0006] The present invention has been made in view of the above points, and an object of the present invention is to provide a production method for obtaining edible oils and fats that have a low content of trans fatty acids and are also excellent in other qualities. [Means for solving the problem]

[0007] In a first aspect, the present invention provides a method for producing edible fats and oils by refining crude oil obtained from a fat and oil raw material, wherein the refining process includes a deodorizing step, and the deodorizing step is carried out while satisfying all of the following conditions 1) to 3): 1) Temperature is 210℃ or higher and 220℃ or lower 2) Vacuum level is over 2.1 Torr and 4.0 Torr or less 3) The amount of water vapor supplied to the oil or fat in the deodorizing process is 0.5% by mass or more and less than 2.5% by mass.

[0008] According to the method for producing edible oils and fats provided by the present invention, edible oils and fats with a low content of trans fatty acids can be obtained. Furthermore, edible oils and fats with a low acid value (AV) and excellent oxidation stability can be obtained. This makes it possible to delay the deterioration of edible oils and fats. Furthermore, it is possible to obtain edible oils and fats with excellent release properties, i.e., the effect of preventing the adhesion of heated materials (food ingredients) to the surface of cooking utensils such as frying pans.

[0009] In the method for producing edible fats and oils provided by the present invention, the degree of vacuum in the deodorizing step is preferably greater than 2.5 Torr and equal to or less than 4.0 Torr.

[0010] In the above-mentioned method for producing edible fats and oils provided by the present invention, the refining treatment preferably includes a deacidification step, and in the deacidification step, the addition ratio of the alkaline substance relative to the neutralization equivalent of the acidic substance contained in the fat or oil to which the deacidification step is carried out is preferably 1.0 or more and 1.4 or less.

[0011] According to this embodiment, it is possible to obtain an excellent edible oil by preventing the adhesion of the material to be heated (foodstuffs) to the surface of the cooking utensil such as a frying pan. It is also possible to obtain an edible oil with a low acid value (AV) and excellent oxidation stability.

[0012] In the method for producing edible fats and oils provided by the present invention, the fat and oil raw material is preferably soybean or rapeseed.

[0013] In a second aspect, the present invention provides use of edible oils and fats produced by the above-mentioned method for producing edible oils and fats for cooking with heat.

[0014] The use of the edible oils and fats provided by the present invention makes it possible to reduce the amount of trans fatty acids contained in cooked foods and to prevent the adhesion of heated materials (food ingredients) to the surface of cooking utensils such as frying pans.

[0015] In using the edible oil and fat provided by the present invention, the cooking is preferably stir-frying. Also, the cooking is preferably frying.

[0016] In a third aspect, the present invention provides a method for inhibiting adhesion of food ingredients to a cooking utensil, the method comprising the step of stir-frying food ingredients in the cooking utensil using edible oil or fat produced by the above-mentioned method for producing edible oil or fat.

[0017] According to the method for inhibiting adhesion of ingredients to a cooking utensil for heating provided by the present invention, it is possible to prevent the material to be heated (ingredients) from adhering to the surface of a cooking utensil for heating, such as a frying pan. DETAILED DESCRIPTION OF THE INVENTION

[0018] Preferred embodiments of the present invention will now be described in detail. Edible oils and fats are produced by refining crude oils obtained from raw oils and fats. Refining is a process for removing impurities contained in the crude oil. Refining processes include, for example, degumming, deacidification, bleaching, and deodorization.

[0019] The degumming process is a process for hydrating and removing gums, primarily composed of phospholipids, contained in raw oils and fats such as crude oil. The degumming process can be carried out, for example, by adding steam or water to the raw oil and fats such as crude oil and stirring the mixture. This hydrates the gums and transfers them to the aqueous layer. Therefore, by removing the aqueous layer, the gums are removed from the raw oil and fats such as crude oil. The degumming process may also be carried out by adding a degumming agent. Examples of the degumming agent that can be used include an aqueous solution of an organic acid such as oxalic acid, citric acid, or phosphoric acid.

[0020] The deacidification process is a process for removing free fatty acids contained in raw oils and fats such as crude oil as soap components. The deacidification process is not limited, but can be carried out, for example, by treating raw oils and fats such as crude oil with an aqueous solution in which an alkaline substance such as sodium carbonate or caustic soda is dissolved in water. The free fatty acids contained in raw oils and fats such as crude oil are converted into soap by the alkaline aqueous solution, and by removing the soap, the free fatty acids are removed from the raw oils and fats such as crude oil.

[0021] The decolorization process is a process for removing pigments contained in raw oils and fats such as crude oil. The decolorization process is not limited, but can be carried out, for example, by adsorbing the pigments onto activated clay, activated carbon, etc. The activated clay, etc. to which the pigments are attached is removed, for example, by vacuum filtration, etc.

[0022] The deodorizing step is a step of removing odorous components contained in raw oils and fats such as crude oil. The deodorizing step is not limited, but can be carried out, for example, by steam distillation under reduced pressure.

[0023] In the present invention, in the method for producing edible fats and oils by subjecting crude oil obtained from a fat and oil raw material to a refining treatment, at least a deodorizing step is carried out as part of the refining treatment.

[0024] The fat and oil raw material used in the present invention is not particularly limited, but examples thereof include plant raw materials such as soybean, coconut, palm, rapeseed, rice, corn germ, cottonseed, safflower, sunflower, olive, flaxseed, peanut, sesame, perilla, pumpkin, almond, etc. The fat and oil raw material is preferably soybean or rapeseed.

[0025] The crude oil used in the present invention may be, for example, a pressed oil obtained by pressing a fat or oil raw material, or an extracted oil obtained by extracting a fat or oil raw material. Alternatively, the crude oil may be a mixture of the pressed oil and the extracted oil.

[0026] The oil and fat raw material can be compressed using, but is not limited to, an expeller compressor comprising a cylindrical casing and a rotatable screw mounted inside the casing, for example.

[0027] The extraction of the fat or oil raw material can be carried out, for example, by contacting the residue after pressing or squeezing the fat or oil raw material with a solvent, extracting the residue, and then distilling off the solvent to obtain an oil. Examples of solvents used for extraction include hexane.

[0028] In the present invention, this deodorization step is carried out at a temperature of 210°C or higher and 220°C or lower. If the temperature in the deodorization step is lower than 210°C, the removal of free fatty acids and odors tends to be insufficient, while if it exceeds 220°C, trans fatty acids tend to be more likely to be produced. It is more preferable to carry out the deodorization step at a temperature of 215°C or higher and 220°C or lower.

[0029] In the present invention, the deodorizing step is carried out under conditions where the degree of vacuum is greater than 2.1 Torr and not greater than 4.0 Torr. If the degree of vacuum in the deodorizing step is outside the above range, the removal of free fatty acids, odors, etc. tends to be insufficient. The deodorizing step is more preferably carried out under conditions where the degree of vacuum is greater than 2.5 Torr and not greater than 4.0 Torr, and even more preferably under conditions where the degree of vacuum is greater than 2.5 Torr and not greater than 3.1 Torr.

[0030] In the present invention, the deodorization step is carried out under conditions in which the amount of steam supplied to the oil or fat to be subjected to the deodorization step is 0.5% by mass or more and less than 2.5% by mass. If the amount of steam supplied to the deodorization step is less than 0.5% by mass, the removal of free fatty acids and odors tends to be insufficient, resulting in a decrease in the quality of the refined oil. If the amount of steam supplied to the deodorization step is more than 2.5% by mass, the degree of vacuum in the deodorization step tends to decrease, resulting in a decrease in the quality of the refined oil. It is more preferable that the deodorization step be carried out under conditions in which the amount of steam supplied to the oil or fat to be subjected to the deodorization step is 1.0% by mass or more and 2.0% by mass or less.

[0031] The processing time for the deodorization step is not particularly limited, but is preferably carried out for 25 minutes or more and 100 minutes or less after the temperature of the oil or fat reaches the set temperature, more preferably for 30 minutes or more and 90 minutes or less, and even more preferably for 40 minutes or more and 80 minutes or less.

[0032] By carrying out the deodorization process under the above conditions, it is possible to reduce the amount of trans fatty acids produced in edible oils and fats, and to obtain edible oils and fats having a trans fatty acid content of preferably 0.3% by mass or less, more preferably 0.2% by mass or less. Furthermore, it is possible to obtain edible oils and fats that not only have a low trans fatty acid content, but also have a low acid value, excellent oxidation stability, and excellent release properties, which prevent the adhesion of heated materials (foodstuffs) to the surface of cooking utensils such as frying pans.

[0033] In a non-limiting embodiment of the present invention, as a refining process performed on crude oil obtained from a fat or oil raw material, the deoxidation process preferably has an alkaline substance addition ratio (hereinafter simply referred to as alkali addition ratio) of 1.0 to 1.4 relative to the neutralization equivalent of the acidic substance contained in the fat or oil to be deoxidized. If the alkali addition ratio is less than 1.0, the removal of free fatty acids tends to be insufficient, resulting in a decrease in the quality of the refined oil. If the alkali addition ratio exceeds 1.4, the effect of preventing the adhesion of heated materials (food ingredients) to the surface of cooking utensils such as frying pans tends to be insufficient. The alkali addition ratio is more preferably 1.0 to 1.3, and even more preferably 1.1 to 1.3. In this specification, the "neutralization equivalent of the acidic substance contained in the fat or oil to be deoxidized" can be measured, for example, by neutralization titration.

[0034] By setting the amount of alkaline substance added in the deoxidation step within the above range, it is possible to obtain edible oils and fats that are excellent in preventing the adhesion of heated materials (food ingredients) to the surface of cooking utensils such as frying pans. It is also possible to reduce the acid value (AV) of the edible oils and fats. As a result, it is possible to delay the deterioration of the edible oils and fats.

[0035] In the present invention, as described above, it is sufficient to carry out at least a deodorization step or, optionally, a deoxidation step as a refining process for raw oils and fats such as crude oil, and there are no particular restrictions on the order in which the various refining process steps are carried out. However, when a degumming step is carried out, it is preferably carried out on crude oil prepared by pressing, extraction, etc., and the deoxidation step is preferably carried out thereafter. When a bleaching step is carried out, it is preferably carried out after the deoxidation step, and the deodorization step is preferably carried out after either step.

[0036] The edible oils and fats provided by the present invention have a low content of trans fatty acids, a low acid value, excellent oxidation stability, and excellent release properties, and are therefore particularly suitable as edible oils and fats for cooking with heat.

[0037] Examples of cooked foods to which the edible oils and fats provided by the present invention can be applied include fried foods such as tempura, French fries, hash browns, croquettes, fried chicken, pork cutlets, fried fish, corn dogs, chicken nuggets, deep-fried tofu, donuts, deep-fried bread, deep-fried rice crackers, snacks, and instant ramen; stir-fried dishes such as yakisoba, stir-fried pork with green peppers, stir-fried pork with vegetables, fried fish, fried rice, and stir-fried vegetables; baked goods such as gyoza, okonomiyaki, takoyaki, grilled meat, grilled fish, tamagoyaki (rolled omelet), grilled rice balls, pancakes, and crepes; and bakery foods such as bread, pies, Danish pastries, muffins, tarts, waffles, and cakes. [Example]

[0038] [Test Example 1] (Sample Preparation) Degummed soybean oil or degummed rapeseed oil (both manufactured by J-Oil Mills Co., Ltd.) was subjected to a deacidification step, a bleaching step, and a deodorization step to prepare samples of Comparative Examples 1 to 4 and Examples 1 to 5.

[0039] (Deoxidation process) After heating the degummed oil to 80°C, 0.06% by mass of an 85% by mass aqueous phosphoric acid solution was added to the raw oil and stirred for 10 minutes. A 15% by mass aqueous sodium hydroxide solution was then added, and the mixture was stirred at 80°C for 20 minutes. The aqueous phase was removed by centrifugation, and 15% by mass of distilled water was added. The mixture was stirred at 80°C for 3 minutes, and the aqueous phase was then removed by centrifugation. In Table 1, the ratio of the addition ratio of the alkaline substance to the neutralization equivalent of the acidic substance contained in the oil or fat, such as phosphoric acid, is shown as the alkali addition ratio.

[0040] (Decolorization process) The deacidified oil that had undergone the deacidification step was heated to 80°C, and then 0.8% by mass of activated clay (Galleon Earth V2, manufactured by Mizusawa Industrial Chemicals) was added to the soybean deacidified oil or rapeseed deacidified oil used in Comparative Examples 1, 2, and 4 and Examples 1, 2, 4, and 5, 0.45% by mass of activated clay (Galleon Earth V2, manufactured by Mizusawa Industrial Chemicals) was added to the soybean deacidified oil used in Comparative Example 3, and 1.5% by mass of activated clay (Galleon Earth GSF, manufactured by Mizusawa Industrial Chemicals) was added to the rapeseed deacidified oil used in Example 3. The mixture was stirred at 80°C under reduced pressure for 30 minutes and then filtered to obtain decolorized oil.

[0041] (Deodorization process) A Claisen flask (volume 1 L) was charged with 500 g of the bleached oil that had been subjected to the decolorization process, and heat treatment was carried out batchwise under reduced pressure while blowing steam into the oil. In Comparative Example 3, the deodorization treatment was carried out using a tray-type deodorizing device. The amount of steam in Table 1 refers to the amount of water (mass%) blown into the bleached oil as steam. The pressure (degree of vacuum) in Table 1 refers to the pressure during the deodorization process.

[0042] (Measurement of physical properties) The samples of Comparative Examples 1 to 4 and Examples 1 to 5 were examined for acid value (AV), trans fatty acid (hereinafter also referred to as trans acid) content (mass %) (trans acid %), oxidation stability (CDM), and demolding property.

[0043] The acid value (AV) was measured in accordance with Standard Methods for the Analysis of Fats, Oils and Related Materials 2.3.1-2013 (Japan Oil Chemists' Society).

[0044] The trans fatty acid content (mass%) (trans fatty acid %) was measured in accordance with Standard Methods for the Analysis of Fats, Oils and Related Materials 2.4.4.3-2013 (Japan Oil Chemists' Society). However, the amount of trans fatty acids was calculated using the area percentage method rather than the internal standard method.

[0045] The releasability was measured under the following conditions. (Release test) (1) The test oil (6 g) was added to a stainless steel frying pan and heated using an induction heater until the surface temperature at the center reached 230°C. (2) Add rice (200g), soy sauce (2g), and sugar (2g) in that order and stir-fry for 30 seconds. (3) The rice was spread over the entire frying pan and left to heat for 1 minute and 30 seconds. (4) The frying pan was turned over for 30 seconds. (5) The weight of the rice remaining in the frying pan was measured.

[0046] The oxidation stability (CDM) was measured in accordance with Standard Method for Analysis of Fats, Oils and Related Materials 2.5.1.2-2013 (Japan Oil Chemists' Society) at a temperature of 97.8°C.

[0047] The acid value (AV), trans fatty acid content (trans fatty acid %), oxidation stability (CDM), and demolding property measured by the above methods are shown in Table 1.

[0048] [Table 1]

[0049] As a result, as shown in Table 1, when edible oils and fats are produced by subjecting degummed oil obtained from soybeans or rapeseed to a refining process including deacidification, bleaching, and deodorization, the deodorization process is carried out under conditions where the temperature is 210°C or higher and 220°C or lower, the degree of vacuum is greater than 2.1 Torr and less than 4.0 Torr, and the amount of steam supplied to the oils and fats subjected to the deodorization process is 0.5% by mass or higher and less than 2.5% by mass, thereby enabling the production of edible oils and fats that have a low content of trans fatty acids and are also excellent in other qualities such as acid value, oxidation stability, and release properties.

Claims

1. A method for producing edible oils and fats by refining crude oil obtained from an oil and fat raw material, The edible oil and fat is for stir-frying, The purification process includes a deacidification step and a deodorization step, In the deacidification step, the addition ratio of the alkaline substance to the neutralization equivalent of the acidic substance contained in the oil or fat to which the deacidification step is performed is 1.0 or more and 1.3 or less, the acidic substance comprises phosphoric acid; A method for producing edible oils and fats, characterized in that the deodorizing step is carried out while satisfying all of the following conditions 1) to 3): 1) Temperature is 210°C or higher and 220°C or lower 2) Vacuum level is over 2.1 Torr and 4.0 Torr or less 3) The amount of water vapor supplied to the oil or fat in the deodorizing step is 0.5% by mass or more and less than 2.5% by mass.

2. 2. The method for producing edible oils and fats according to claim 1, wherein the vacuum degree condition in the deodorizing step is more than 2.5 Torr and 4.0 Torr or less.

3. The method for producing edible fats and oils according to claim 1 or 2, wherein the fat and oil raw material is soybean or rapeseed.

4. Use of edible oils and fats produced by the method for producing edible oils and fats according to any one of claims 1 to 3 for cooking, The above use, wherein the cooking by heating is stir-frying.

5. A method for inhibiting adhesion of food ingredients to a cooking utensil, comprising a step of frying food ingredients in the cooking utensil using the cooking oil produced by the cooking oil production method of any one of claims 1 to 3.

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