JP4463586B2 - Soybean oil purification method - Google Patents

Description

The present invention relates to a method for refining soybean oil , and in particular, a soybean oil composition having excellent flavor stability, including refined soybean oil in which a triene fatty acid having a conjugated double bond structure (hereinafter referred to as “conjugated triene fatty acid”) is reduced. The present invention relates to a method for refining soybean oil in food.

  Products such as edible oil and mayonnaise, which are stored for a long time in the shelves of supermarkets and retail stores and in the storage of consumers, are subject to various oxidization and decomposition caused by heat and light, and the flavor deteriorates. The occurrence of off-flavors and off-flavors, the generation of irritating odors, the occurrence of miscellaneous tastes, etc. In particular, when a transparent container is filled and exposed to light, the deterioration is severe. For example, refined soybean oil, which is a main raw material of edible oil, produces a green bean odor and a hay-like unpleasant odor during storage. This phenomenon is called a return odor and occurs very early after the production of soybean oil. Although various theories have been reported as a causative substance of the back odor, the actual state is unknown (see Non-Patent Document 1).

  As fats and oils which tried to prevent flavor deterioration as described above, for example, there is edible fats and oils obtained by filtering edible fats and oils subjected to deodorizing treatment with activated carbon (see Patent Document 1). According to this invention, there is little heating odor, generation of a return odor is suppressed, and it is described that edible fats and oils excellent in flavor can be produced.

In addition, the fat is brought into contact with a non-polar solvent and a two-component solvent having different polarities of an alkaline alcohol, the deoxidized fat is recovered and deoxidized in the nonpolar solvent, and the deoxidized fat is further adsorbed by a porous substance. There exists refined fats and oils obtained by making it contact with an agent and decoloring (refer patent document 2). According to this invention, it is described that it is possible to obtain refined fats and oils that have good oxidation stability and are less likely to generate a return odor.
JP 2003-61577 A JP 2002-212586 A Endo Yasushi, “Odor components of edible fats and oils”, Journal of the Japan Oil Chemists' Society Vol. 48, No. 10 (1999) p. 1133-1140

  However, according to the conventional methods for refining fats and oils such as Patent Document 1 and Patent Document 2, both of them require an additional purification step for improving the flavor stability, and the flavor is more easily obtained. There has been a demand for a method for refining fats and oils that can improve stability.

Accordingly, an object of the present invention is to provide in a simple method, the soybean oil purifying method of soybean oil composition with excellent purified soybean oil flavor stability used in the raw material.

  As a result of intensive studies to achieve the above-mentioned problems, the present inventors have found that the flavor stability of the oil composition can be improved by reducing the amount of conjugated triene fatty acid generated in the oil purification process, The present invention has been completed.

In order to achieve the above object, the present invention provides a method for purifying soybean oil including a decolorization step, wherein the soybean oil contains activated carbon and activated clay in combination (active clay usage: oil wt%) × (treatment temperature: ° C.) from 5 to 25, the treatment temperature is soybean oil, characterized in that the activated carbon treatment and activated clay treatment is simultaneously performed decoloration treatment under conditions comprising a 10 to 50 ° C. A purification method is provided.

  According to the present invention, it is possible to reduce the amount of conjugated triene fatty acid that deteriorates flavor stability, so that an edible oil excellent in flavor stability is provided, and a food excellent in flavor stability containing the edible oil. Furthermore, it is possible to provide a simple method for purifying fats and oils in an oil and fat composition having excellent flavor stability.

  Moreover, according to this invention, the food oil excellent in flavor and the flavor stability, and the foodstuff excellent in the flavor containing the said cooking oil, and excellent in flavor stability can be provided.

  Hereinafter, the present invention will be specifically described.

  The fat and oil composition of the present invention contains fat and oil that has undergone a purification process, and the ratio of the conjugated triene fatty acid to the fatty acid in the fat and oil is 0.035% by mass or less. More preferably, it is 0.030 mass% or less, More preferably, it is 0.020 mass% or less, Most preferably, it is 0.010 mass% or less. The lower the ratio of the conjugated triene fatty acid to the fatty acid in the fat or oil, that is, the lower the amount of conjugated triene fatty acid generated in the purification step, the better the flavor stability.

  As a fatty acid having a conjugated double bond in the molecule, conjugated linoleic acid (CLA) is well known. CLA is contained in beef and dairy products by about 1%, and there are many reports on nutritional functionality. On the other hand, conjugated linolenic acid (CLN) has been found in certain plant seed oils. For example, tung oil usually contains 70% or more of eleostearic acid containing 70% by mass or more of conjugated triene, and bittern or pomegranate seeds contain 60% or more of CLN having a conjugated triene structure. CLN is not included in the raw material oil for animal and vegetable oils used for cooking oil.

  The conjugated triene fatty acid has three double bonds, and two or more double bonds are conjugated, and specific examples include α-eleostearic acid and β-eleostearic acid. In the present invention, in particular, α-eleostearic acid and / or β-eleostearic acid.

  Conjugated triene fatty acid in the present invention creates a calibration curve using α-eleostearic acid and β-eleostearic acid such as tung oil, and a small amount of α-eleostearic acid and β contained in the test fat and oil. -It can be measured by HPLC equipped with a UV detector using eleostearic acid as a methyl ester.

  The purification process in the present invention refers to a general oil and fat purification process such as degumming, deoxidation, decolorization, and deodorization process, and particularly means a purification process including a decolorization process. More specifically, for example, a decoloring step using activated clay as a decolorizing agent. However, any purification step capable of generating conjugated triene fatty acids is within the scope of the present invention, and the amount of conjugated triene fatty acids generated can be reduced by appropriately adjusting the purification conditions.

  It has been clarified in the present invention that conjugated triene fatty acids are not contained in unrefined oils of animal and vegetable oils generally used for food, but are generated and increased in the oil refining process. Therefore, there is no generation of conjugated triene fatty acids that affect the flavor stability without going through a refining process. Is bad and needs to be purified.

  The present invention is an oil and fat composition containing a fat and oil mainly composed of refined oil, and the refined oil in the oil and fat composition is preferably 70 to 100% by mass, and 90 to 100% by mass with respect to the total amount of oil and fat. More preferably.

  The fats and oils used in the present invention are not particularly limited, but are preferably fats and oils that do not contain conjugated triene fatty acid, particularly α- and β-eleostearic acid in an unpurified state.

  Specifically, for example, soybean oil, soybean germ oil, rapeseed oil, high oleic rapeseed oil, corn oil, sesame oil, perilla oil, linseed oil, peanut oil, safflower oil, safflower oil, high oleic safflower oil, sunflower oil, mid oleic Sunflower oil, high oleic sunflower oil, cottonseed oil, grape seed oil, macadamia nut oil, hazelnut oil, pumpkin seed oil, walnut oil, coconut oil, tea seed oil, egoma oil, borage oil, olive oil, rice bran oil, wheat germ oil, palm Oil, palm kernel oil, palm oil, cacao butter, beef tallow, lard, chicken tallow, milk fat, fish oil, seal oil, algal oil, and other synthetic oils such as diglycerides and medium chain fatty acid triglycerides, fractionated oils, transesterification Among them, animal and vegetable oils are preferable, and soybean oil, soybean germ oil, rapeseed oil, linseed oil and perilla oil are particularly preferable.

  As described above, refined oils are used in the range of 70 to 100% by mass with respect to the total amount of oils and fats as described above. However, in the range of 0 to 30% by mass, preferred flavors such as roasted sesame oil and olive oil are used. It can be flavored by adding unskilled products.

  In the present invention, it is possible to obtain a refined oil with reduced conjugated triene fatty acids by performing special refining. Specifically, by controlling the use conditions of activated clay used in oil refining, The invention can be achieved.

  In refining general fats and oils, 0.5 to 2% by mass of activated clay is added and treated at 105 to 120 ° C. ((active clay used amount: mass% of oil) × (treatment temperature: ° C.) = 52.5. ˜240), the color and flavor are improved, but the flavor stability is not sufficient. In the present invention, flavor stability can be improved by lowering the treatment temperature or reducing the amount of activated clay used.

  In the oil and fat refining step, (active clay use amount: mass% of oil) × (treatment temperature: ° C.) is preferably 0-50, more preferably 5-50. From the viewpoint of flavor stability, a value of 5 to 40 is particularly preferable. The use amount of the activated clay is preferably 0.1 to 1% by mass, and the treatment temperature is preferably 30 to 100 ° C.

  Here, (active clay usage: oil mass%) × (treatment temperature: ° C.) is 0-50, (active clay usage: oil mass%) × (treatment temperature: ° C.) is 0. -50 and active clay usage> 0, and active clay usage = 0. When the amount of active clay used is 0, for example, activated carbon is used as a decolorizing agent in an amount of 0.1 to 3.0% by mass, preferably 0.3 to 2.5% by mass, based on the amount of oil and fat, and a processing temperature of 30 to 30%. By purifying at 100 ° C, preferably 40 to 80 ° C, the effects of the present invention can be obtained.

  In the range of the above-mentioned conditions, the flavor stability is good, but the flavor level may be slightly inferior. In that case, in order to improve a flavor level, it is preferable to use activated carbon together at the time of decoloring. The activated carbon treatment can be carried out simultaneously with the activated clay treatment, but can also be carried out separately. In addition, about 0.1-3 mass% is preferable with respect to fats and oils, and, as for the addition amount of activated carbon, 0.3-2 mass% is further more preferable. Moreover, 10-120 degreeC is preferable and the process temperature has more preferable 20-105 degreeC.

  The decoloring treatment is performed under reduced pressure, but in the present invention, it can be performed under reduced pressure conditions or normal pressure conditions. However, when it is carried out under normal pressure conditions, it is preferable to remove water from the activated clay and activated carbon before the decolorization treatment.

  The oil and fat composition of the present invention comprises, as necessary, an antioxidant such as tocopherol and ascorbic acid ester, glycerin fatty acid ester, organic acid monoglyceride, polyglycerin fatty acid ester, polyglycerin condensed ricinoleic acid ester, sorbitan fatty acid ester, sorbitol fatty acid Emulsifiers such as esters, propylene glycol fatty acid esters and sucrose fatty acid esters, and oil-soluble components such as carotenes, phytosterols and phytosterol esters can be contained, but the type and amount are not particularly limited.

  Moreover, the foodstuffs with favorable flavor stability can be obtained by using the fats and oils composition of this invention for the fats and oils in foodstuffs. For example, by using the oil and fat composition of the present invention as a raw material for the emulsified oil and fat, an emulsified oil and fat composition with improved flavor stability can be provided.

  Although not particularly limited as a food to be applied, for example, mayonnaise, margarine, fat spread, emulsified dressing, ice cream, emulsified oil and fat composition such as cream, cutlet, croquette, tempura, fried chicken, french fries, etc. In addition to fried foods, stir-fried vegetables, fried rice and other fried rice, Western confectionery, and noodles. In particular, it is preferably applied to emulsified oil and fat compositions. Each of these foods can be produced by a normal production method.

  Moreover, it is preferable that it is 70-100 mass% of the fats and oils added to foodstuffs, and, as for the usage-amount of the oil-fat composition of this invention in foodstuffs, it is more preferable that it is 80-100 mass%. If it is less than 70% by mass, the effect on the flavor stability of the oil and fat composition of the present invention is small, and the effect of using the oil and fat composition of the present invention is hardly obtained. As fats and oils added in addition to the oil and fat composition of the present invention, specifically, unrefined roasted sesame oil, unrefined olive oil, soybean oil, soybean germ oil, rapeseed oil, Oleic rapeseed oil, corn oil, sesame oil, perilla oil, flaxseed oil, peanut oil, safflower oil, safflower oil, sunflower oil, mid oleic sunflower oil, sunflower oil with high oleic acid, cottonseed oil, grape seed oil, macadamia nut oil , Hazelnut oil, pumpkin seed oil, walnut oil, straw oil, tea seed oil, sesame oil, borage oil, olive oil, rice bran oil, wheat germ oil, palm oil, palm kernel oil, palm oil, cacao butter, beef tallow, lard, chicken Fats, milk fats, fish oils, seal oils, algal oils and other oils, as well as synthetic and fractionated oils such as diglycerides and medium chain triglycerides, transesterified oils, hydrogenated oils It is, but not particularly limited.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

<Analytical method of conjugated triene fatty acid>
The amounts of α and β-eleostearic acid in tung oil were measured, and calibration curves of α and β-eleostearic acid were prepared by changing the concentration of tung oil (FIG. 1). Using the same calibration curve, α and β-eleostearic acid, which is a conjugated triene fatty acid contained in a trace amount in the sample fat, was analyzed. The detailed method will be described below.

(Methylation of MCT and Tung Oil)
About 100 mg of medium chain fatty acid triglyceride (MCT) was precisely weighed into a stoppered test tube, and 2 mL of 5% CH ₃ ONa / CH ₃ OH solution was added. After filling with nitrogen, the mixture was reacted at 55 ° C. for 30 minutes, allowed to cool, 2 mL of distilled water was added and mixed, and 2 mL of hexane was further added and extracted twice. The hexane phase was washed with distilled water until the aqueous phase became neutral, dried over anhydrous sodium sulfate, and then the solvent was removed under an evaporator and a nitrogen stream. The same operation was performed 3 times to obtain MCT methyl ester.
Similarly, tung oil was methyl esterified to obtain tung oil methyl ester.

(MCT methyl ester concentration adjustment)
100 mg of MCT methyl ester was weighed into a 100 mL volumetric flask, and hexane was added to adjust to 1.0 mg / mL.

(Concentration adjustment of methyl α and β-eleostearate)
The contents (composition mass%) of α and β-eleostearic acid in tung oil methyl ester were measured by gas chromatography. From the values, the concentrations of α and β-methyl eleostearate necessary for preparing a calibration curve were calculated to prepare a Tung oil / hexane solution of X _α and X _β (mg / mL). Gas chromatography (GC) conditions and calculation formulas are as follows.

GC analysis condition GC: GC-14B [Shimadzu]
Integrator: C-R3A [Shimadzu]
Column: Fused Sillica Capillary ColumnOmegawax320 (30m × 0.32id) [Spelco]
Column temperature: 200 ° C
Inlet temperature: 250 ° C
FID detector temperature: 260 ° C
Carrier gas: He
Carrier gas pressure: 50kPa

Calculation formula X _α = 5 × 0.02 / 100 × 100 / K _α
X _β = 5 × 0.02 / 100 × 100 / K _β
X _α (mg): Mass of tung oil methyl ester necessary for methyl α-eleostearate to be about 0.02 mass% with respect to 5 mg MCT methyl ester X _β (mg): β with respect to 5 mg MCT methyl ester - eleostearic acid methyl mass K _alpha tung oil methyl ester required to be about 0.02 wt% (fatty acid composition by weight%): content of α- eleostearic acid in methyl tung K _beta (fatty Composition (mass%): content of methyl β-eleostearate in tung oil

(Preparation of calibration curve and determination of eleostearic acid)
MCT methyl ester / hexane solution (1.0 mg / mL) tung in Baiyarubin which takes 5mL of methyl ester / hexane solution _(X α mg / mL) was placed in each 1,2,3,4,5mL a whole pipette. After evaporating the solvent with nitrogen, 1 mL of 0.05% by mass butyl benzoate / methanol solution was added to each sample, and this was used as a sample for preparing a calibration curve of methyl α-eleostearate. A calibration curve sample for methyl β-eleostearate was also prepared in the same manner.
A calibration curve preparation sample was analyzed by HPLC equipped with a UV detector to prepare a calibration curve (FIG. 1).

  For the oil to be analyzed (sample oil), prepare a methyl ester / hexane solution in the same manner as when MCT and tung oil were methylated, put about 10.0 mg of hexane solution into vials, and evaporate the solvent with nitrogen. After that, 1 mL of 0.05 mass% butyl benzoate / methanol solution was added and analyzed by HPLC, and the contents of α-eleostearic acid and β-eleostearic acid were examined from the calibration curve.

HPLC analysis condition pump: L-7100 (Hitachi)
Detector: L-7420 (Hitachi)
Integrator: D-2500 (Hitachi)
Flow rate: 1.0 mL / min, CH ₃ OH: H ₂ O / 85: 15
Column: COSMOSIL 5C18-AR 4.6 × 150mm (Nacalai Tesque)
Guard column: Develosil-ODS-UG 4.0 × 10mm (Nomura Chemical)
Detection wavelength: UV274nm
Column temperature: Room temperature (20 ° C)

<Examples 1 to 4, Reference Examples 1 to 5 and Comparative Examples 1 to 5>
As shown in Tables 1 and 2, activated clay and / or activated carbon were added to 100 kg of soybean deoxidized oil, and decolorization was performed at 40 to 110 ° C. for 20 minutes. After decoloring, deodorization was performed according to a conventional method to obtain soybean oil 1 to 10 (Examples 1 to 2, Reference Examples 1 to 4 , Comparative Examples 1 to 4).
Furthermore, fats and oils were blended in the formulation shown in Table 3 to obtain mixed oils 1 to 4 (Examples 3 to 4, Reference Example 5 and Comparative Example 5).

  About each obtained oil, the content of the conjugated triene fatty acid ((alpha) -eleostearic acid and (beta) -eleostearic acid) was measured by said analysis method. The results are shown in Tables 1-3.

Moreover, about each obtained oil, the flavor was evaluated as follows.
First, a 5-stage evaluation (5: excellent to 1: very bad) was performed on the flavor immediately after purification. Furthermore, after putting 600 g of oil into a PET bottle and conducting storage test 1 (60 ° C., 1 week) and storage test 2 (3000 lux, 3 weeks), the flavors were compared, and a five-step evaluation was performed in the same manner. went. The results are shown in Tables 1-3.
<Taste evaluation>
5 ... Excellent 4 ... Good 3 ... Acceptable 2 ... Slightly bad 1 ... Very bad

From the results of evaluation, Examples 1-4 and Reference Examples 1-5 , in which the content of conjugated triene fatty acid is less than 0.035% by mass, are both comparative examples in which the content of conjugated triene fatty acid is more than 0.035% by mass. It turned out that flavor stability is excellent compared with 1-5.

In addition, Examples 1-2 and Reference Examples 1-4 , in which the amount of activated clay x treatment temperature is 50 or less, are more stable in flavor than Comparative Examples 1-4 in which the amount of activated clay x treatment temperature is greater than 50. It was found that the property is excellent.

< Reference Example 6 and Comparative Example 6>
As shown in Table 4, activated clay or activated clay and activated carbon were added to 100 kg of rapeseed deoxidized oil, and decolorization was performed at 50 ° C. for 20 minutes. After decolorization, deodorization was performed according to a conventional method to obtain rapeseed oils 1 and 2 ( Reference Example 6 and Comparative Example 6).

  About each obtained oil, the content of the conjugated triene fatty acid ((alpha) -eleostearic acid and (beta) -eleostearic acid) was measured by said analysis method. The results are shown in Table 4.

Moreover, about each obtained oil, the flavor was evaluated as follows.
First, a 5-stage evaluation (5: excellent to 1: very bad) was performed on the flavor immediately after purification. Furthermore, 600 g of oil was put in each PET bottle, and after storage test 1 (60 ° C., 1 week) and storage test 2 (3000 lux, 3 weeks), the flavors were compared, and a five-step evaluation was performed in the same manner. went. The results are shown in Table 4.
<Taste evaluation>
5 ... Excellent 4 ... Good 3 ... Acceptable 2 ... Slightly bad 1 ... Very bad

From the results of evaluation, Reference Example 6 having a conjugated triene fatty acid content of less than 0.035% by mass is superior in flavor stability to Comparative Example 6 having a conjugated triene fatty acid content of more than 0.035% by mass. I found out.
Moreover, it turned out that the reference example 6 whose amount of activated clay x process temperature is 50 or less is excellent in flavor stability compared with the comparative example 6 whose amount of activated clay x process temperature is larger than 50.

<Examples 5 to 6 , Reference Example 7 and Comparative Example 7>
The ingredients shown in Table 5 were mixed in a conventional manner, and a mayonnaise was manufactured using a vacuum emulsifier. The flavor immediately after production and after 7 months at room temperature was evaluated.
From the results of the evaluation, it was found that the flavor stability of the mayonnaise of Examples 5 to 6 and Reference Example 7 was improved as compared with the mayonnaise of Comparative Example 7.
<Taste evaluation>
5 ... excellent 4 ... good 3 ... acceptable 2 ... somewhat bad 1 ... very bad

FIG. 1 is a diagram showing calibration curves of α and β-eleostearic acid.

Claims (3)

A method for refining soybean oil including a decolorization step,
In the decolorization step, the soybean oil is a combination of activated carbon and activated clay.
(Activated clay use amount:% by mass of oil) x (treatment temperature: ° C) is 5 to 25 , and activated carbon treatment and activated clay treatment are simultaneously performed and decolorized under the condition that the treatment temperature is 10 to 50 ° C. A method for refining soybean oil characterized by the above. The amount of the activated carbon, the soybean oil refining method according to claim 1 Symbol mounting, characterized in that it is decolored with soy amounts to 0.1-3% by weight conditions. The amount of the activated carbon, wherein 0.3 to 2 wt% relative to the amount of soybean oil, the treatment temperature of the mounting according to claim 1 Symbol, characterized in that it is decolored with conditions. 20 to 50 ° C. soybean oil Purification method.