Method for producing deacidified oil

Abstract

To provide a method capable of efficiently removing free fatty acids in a deacidification step, without using phosphoric acid as a degumming aid.SOLUTION: A production method of deacidified oil obtained by deacidifying crude or degummed oil, comprises an acid addition step of adding and mixing acid with the unrefined or de-gummed oil, an alkali addition step of adding and mixing alkali with the oil after the acid addition step, a warm water addition step of adding warm water at a temperature between 70°C and 90°C to the oil after the alkali addition step, and a centrifugal separation step of separating the soap component from the oil after the warm water addition step by centrifugation.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for producing deacidified oil. [Background technology]

[0002] Edible oils and fats such as soybean oil and rapeseed oil are used as oils for cooking fried foods such as fries and tempura. These edible oils and fats are obtained by subjecting crude oil obtained from oilseed raw materials to a refining process. The refining process includes a degumming process, a deacidification process, a decolorization process, and a deodorization process (see Patent Document 1).

[0003] The degumming process is a process for hydrating and removing gummy substances, the main component of which is phospholipids, contained in the oil. In the degumming process, a degumming aid consisting of an aqueous solution of an acid such as citric acid or phosphoric acid is added to the crude oil, and then steam or water is added and stirred, so that the gummy substances are hydrated and become water-soluble, and move to the aqueous layer, which is then separated into oil and water by centrifugation or the like to obtain degummed oil.

[0004] In the deacidification step, the degummed oil is treated with an aqueous solution of an alkali such as sodium carbonate or sodium hydroxide, and free fatty acids contained in the oil are removed as soap components. When the degumming aid used in the degumming step is phosphoric acid, the free fatty acids can be removed more efficiently in the deacidification step than when the degumming aid is citric acid. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 55-73793 Summary of the Invention [Problem to be solved by the invention]

[0006] Recently, the supply of phosphoric acid has become unstable, and there is a demand for a method for efficiently removing free fatty acids in the deacidification step without using phosphoric acid as the degumming aid.

[0007] Therefore, the problem to be solved by the present invention is to provide a method for efficiently removing free fatty acids in a deacidification step without using phosphoric acid as a degumming aid. [Means for solving the problem]

[0008] The present inventors have conducted extensive research in light of the above problems and have found that if hot water at 70°C to 90°C is added to the fat or oil before oil-water separation is performed after the alkali is added in the deacidification step, free fatty acids can be efficiently removed in the deacidification step without using phosphoric acid as a degumming aid. The present invention has been completed based on these findings.

[0009] The present invention encompasses the aspects and embodiments set forth below. [1] A method for producing deacidified oil by deacidifying unrefined or degummed fats and oils, comprising the steps of: an acid addition step of adding and mixing an acid to the fat and oil; an alkali addition step of adding and mixing an alkali to the fat and oil after the acid addition step; a hot water addition step of adding hot water having a temperature of 70°C or higher but not higher than 90°C to the fat and oil after the alkali addition step; and a centrifugation step of separating soap components from the fat and oil after the hot water addition step by centrifugation. [2] The method for producing deacidified oil described in [1], further comprising an ultrasonic treatment step of treating the oil and fat after the alkali addition step with ultrasonic waves prior to the hot water addition step. [3] The method for producing deacidified oil from fats and oils described in [1], wherein citric acid is added as the acid in the acid addition step. [4] The method for deacidifying fats and oils described in [2], wherein citric acid is added as the acid in the acid addition step. [5] The method for producing deacidified oil described in [3], wherein the amount of citric acid added is in the range of 2 to 5 times, in terms of molar ratio, the total amount of calcium and magnesium contained in the unrefined or degummed oil or fat. [6] A method for producing deacidified oil according to [4], wherein the amount of citric acid added is in the range of 1 to 5 times, in molar ratio, the total amount of calcium and magnesium contained in the unrefined or degummed oil or fat. [7] The method for producing deacidified oil described in any one of [1] to [6], wherein the amount of warm water added is in the range of 1 part by mass or more and 5 parts by mass or less per 100 parts by mass of the oil or fat after the alkali addition step. Effect of the Invention

[0010] The method for producing deacidified oil of the present invention provides a method for producing deacidified oil that can efficiently remove free fatty acids in the deacidification step without using phosphoric acid as a degumming aid. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is an explanatory diagram showing the configuration of one embodiment of the method for producing deacidified oil of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The present invention will now be described in more detail with reference to the drawings. In addition, when a numerical range is indicated, the upper limit and the lower limit can be combined as appropriate, and the numerical range obtained thereby is also considered to be disclosed.

[0013] The method for producing deacidified oil of the present invention includes an acid addition step of adding and mixing an acid with unrefined or degummed fats and oils (FIG. 1, STEP 1). The unrefined fats and oils are crude oils obtained from raw oil materials for edible fats and oils. The degummed fats and oils are fats and oils obtained by subjecting the crude oils to a degumming step.

[0014] The acid is an acid that is commonly used in the degumming process of the crude oil. Examples of the acid include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid, and organic acids such as citric acid, acetic acid, and tartaric acid. One or more of these acids are used. In particular, when citric acid is used, the acid value and soap content can be effectively reduced.

[0015] The amount of citric acid added is preferably in the range of 2 times or more by molar ratio relative to the total amount of calcium and magnesium contained in the unrefined or degummed fats and oils. When the amount of citric acid added is in the above range, the acid value and soap content contained in the unrefined or degummed fats and oils can be more efficiently reduced.

[0016] When the ultrasonic treatment process described later is included, the amount of citric acid added is preferably in the range of 1 or more times the total amount of calcium and magnesium contained in the unrefined or degummed oil / fat in terms of molar ratio. When the amount of citric acid added is in the above range, the acid value and soap content contained in the unrefined or degummed oil / fat can be more efficiently removed.

[0017] From an economical point of view, the amount of citric acid added is preferably 5 times or less, in terms of molar ratio, the total amount of calcium and magnesium contained in the unrefined or degummed fats and oils.

[0018] The method for producing deacidified oil of the present invention includes an alkali adding step of adding an alkali to the fat and oil after the acid adding step and mixing the fat and oil (FIG. 1, STEP 2). Free fatty acids contained in the fat and oil after the acid adding step are removed as soap components in the alkali adding step. The alkali may be added in at least one form selected from an aqueous solution and a solid. The alkali preferably includes at least one selected from the group consisting of an alkali metal hydroxide, an alkali metal carbonate, and ammonia. The alkali metal preferably includes at least one selected from the group consisting of lithium, sodium, potassium, rubidium, cesium, and francium, and more preferably includes at least one selected from the group consisting of sodium and potassium. The alkali preferably includes at least one selected from the group consisting of an aqueous sodium hydroxide solution, an aqueous sodium carbonate solution, and an aqueous ammonia solution, and is more preferably an aqueous sodium hydroxide solution, an aqueous sodium carbonate solution, or an aqueous ammonia solution, and is even more preferably an aqueous sodium hydroxide solution.

[0019] The method for producing deacidified oil of the present invention preferably further includes an ultrasonic treatment step in which the oil after the alkali addition step is treated with ultrasonic waves before the hot water addition step described below (FIG. 1, STEP 2A). When the method for producing deacidified oil of the present invention includes the ultrasonic treatment step, free fatty acids can be removed more efficiently in the deacidification step. The frequency of the ultrasonic waves applied in the ultrasonic treatment step is preferably 20,000 Hz or more and 100,000 Hz or less, more preferably 20,000 Hz or more and 40,000 Hz or less. The treatment time of the ultrasonic treatment step is preferably 1 minute or more and 30 minutes or less, more preferably 5 minutes or more and 15 minutes or less.

[0020] The method for producing deacidified oil of the present invention includes a hot water addition step of adding hot water of 70°C or more and 90°C or less to the fat or oil after the alkali addition step (FIG. 1, STEP 3). If the temperature of the hot water is less than 70°C or more than 90°C, the efficiency of removing free fatty acids and soap components in the deacidification step decreases. The amount of hot water added is preferably in the range of 1 part by mass to 5 parts by mass per 100 parts by mass of the fat or oil after the alkali addition step. When the amount of hot water added is within the above range, free fatty acids and soap components can be removed more efficiently in the deacidification step.

[0021] The method for producing deacidified oil of the present invention includes a centrifugation step of separating soap components from the oil and fat after the hot water addition step by centrifugation (FIG. 1 STEP 4). In the centrifugation step, the deacidified oil and the aqueous layer after the hot water addition step are separated into oil and water. The centrifugal force in the centrifugation step is preferably 200×g or more and 5300×g or less, more preferably 850×g or more and 3400×g or less. The processing time of the centrifugation step is preferably 1 minute or more and 10 minutes or less, more preferably 2 minutes or more and 5 minutes or less. Since the oil layer is separated into an upper layer and the aqueous layer into a lower layer by the centrifugation step, the upper layer is recovered by a method such as decantation to obtain deacidified oil. The deacidified oil separated from the aqueous layer is sequentially subjected to a deacidification step, a decolorization step, and a deodorization step to prepare edible oil and fat. EXAMPLES

[0022] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these.

[0023] In the examples and comparative examples, various physical properties were measured or calculated as follows. <Calcium and magnesium content in degummed oil> The degummed oil was diluted with xylene (special reagent grade, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and the concentrations of calcium and magnesium were quantified by reading the emission intensity at specific wavelengths using an ICP optical emission spectrometer (manufactured by Hitachi High-Tech Science Corporation). The emission intensity at the wavelength of 393.4 nm for calcium and 279.6 nm for magnesium was read for each specific wavelength. The standard reagent used for the quantification was CONOSTAN® Oil·Anlaysis Standard (manufactured by SCP SCIENCE).

[0024] <Acid value> The acid value (mg KOH / g fats and oils) was measured according to the Standard Methods for Analysis of Fats, Oils and Related Materials 2.3.1-2013 (Acid Value).

[0025] <Soap content> The soap content (ppm) was measured according to the Standard Method for Analysis of Fats, Oils and Related Materials 2.6.2-2013 (soap).

[0026] [Example 1] 1000g of degummed fats and oils in a 2L beaker were heated to 80°C while stirring with a propeller, and a 50% by mass aqueous citric acid solution was added so that the molar ratio of citric acid was 1 relative to the total amount of calcium and magnesium contained in the fats and oils (acid addition step), and stirring was continued for 10 minutes. After that, 14mL of an 8.07% by mass aqueous sodium hydroxide solution was added to the fats and oils after the acid addition step (alkali addition step), and stirring was continued for 10 minutes. Next, 3 parts by mass of 80°C hot water was added to 100 parts by mass of the fats and oils after the alkali addition step (hot water addition step), and stirring was continued for 10 minutes. The fats and oils after the hot water addition step were centrifuged at 3000 rpm for 3 minutes, and the oil layer was collected to obtain a deacidified oil from which soap components were separated. 500g of the deacidified oil was heated to 90°C in a 1L beaker while stirring with a propeller, 50mL of 80°C hot water was added, and stirring was continued for another 10 minutes. The resulting mixture of deacidified oil and water was then centrifuged at 3000 rpm for 3 minutes, and the oil layer was collected to obtain refined deacidified oil. The acid value and soap content of the refined deacidified oil were measured. The results are shown in Table 1.

[0027] [Examples 2 and 3] The same operations as in Example 1 were carried out, except that the amount of the citric acid aqueous solution added in the acid addition step was adjusted so that the molar ratio of citric acid to the total amount of calcium and magnesium contained in the oil and fat was 2 (Example 2) or 3 (Example 3), and the acid value and soap content of the refined deacidified oil were measured. The results are shown in Table 1.

[0028] [Example 4] The same operations as in Example 1 were carried out, except that an ultrasonic treatment step of applying ultrasonic treatment at 20,000 Hz for 10 minutes was carried out after the alkali addition step, and the acid value and soap content of the refined deacidified oil were measured. The results are shown in Table 1.

[0029] [Example 5] The same operations as in Example 1 were carried out, except that the amount of the citric acid aqueous solution added in the acid addition step was adjusted so that the molar ratio of citric acid to the total amount of calcium and magnesium contained in the oil and fat was 2, and an ultrasonic treatment step of applying ultrasonic treatment at 20,000 Hz for 10 minutes was carried out after the alkali addition step, and the acid value and soap content of the refined deacidified oil were measured. The results are shown in Table 1.

[0030] [Control Example 1] The same operations as in Example 1 were carried out, except that in the acid addition step, a 75% by mass phosphoric acid aqueous solution was used instead of the citric acid aqueous solution, the amount of phosphoric acid added was set to 1 in molar ratio to the total amount of calcium and magnesium contained in the oil and fat, and the hot water addition step was not carried out, and the acid value and soap content of the refined deacidified oil were measured. The results are shown in Table 1.

[0031] [Comparative Example 1] The same operations as in Example 1 were carried out, except that the amount of the citric acid aqueous solution added in the acid addition step was set to 5 in terms of molar ratio to the total amount of calcium and magnesium contained in the oil and fat (Comparative Example 1), and the warm water addition step was not carried out, and the acid value and soap content of the refined deacidified oil were measured. The results are shown in Table 1.

[0032] [Table 1]

[0033] The acid value and soap content of the deacidified oil produced by the method for producing the deacidified oil including the hot water addition step in Examples 1 to 5 were sufficiently low. In particular, when the method for producing the deacidified oil included ultrasonic treatment, the acid value and soap content of the deacidified oil were further reduced.

Claims

1. A method for producing a deacidified oil by deacidifying unrefined or degummed oils and fats, comprising the steps of: An acid adding step of adding and mixing an acid to the oil and fat; An alkali adding step of adding and mixing an alkali to the fat and oil after the acid adding step; and a hot water adding step of adding hot water having a temperature of 70° C. or higher and 90° C. or lower to the fat and oil after the alkali adding step. A method for producing deacidified oil, comprising a centrifugation step of separating soap components from the oil and fat after the warm water addition step by centrifugation.

2. The method for producing deacidified oil according to claim 1 , further comprising an ultrasonic treatment step of treating the oil and fat after the alkali addition step with ultrasonic waves before the hot water addition step.

3. The method for producing a deacidified oil of fats and oils according to claim 1 , wherein citric acid is added as the acid in the acid addition step.

4. The method for deacidifying fats and oils according to claim 2, wherein citric acid is added as the acid in the acid addition step.

5. A method for producing deacidified oil as described in claim 3, wherein the amount of citric acid added is in the range of 2 to 5 times, in molar ratio, the total amount of calcium and magnesium contained in the unrefined or degummed oil or fat.

6. A method for producing deacidified oil as described in claim 4, wherein the amount of citric acid added is in the range of 1 to 5 times, in molar ratio, the total amount of calcium and magnesium contained in the unrefined or degummed oil or fat.

7. The method for producing deacidified oil according to any one of claims 1 to 6, wherein the amount of hot water added is in the range of 1 part by mass to 5 parts by mass per 100 parts by mass of the oil and fat after the alkali addition step.

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