JP6570832B2 - Method for producing edible fat and oil and method for suppressing return odor - Google Patents

Description

  The present invention relates to a method for producing edible fats and oils.

  In general, in the production of edible fats and oils, raw material oil is obtained through plant seeds / fruits, oil extraction from animals, heating, and solvent extraction steps. Furthermore, the odor derived from the raw material oil is sufficiently removed through purification processes such as a degumming process, a deoxidation process, a decolorization process, and a deodorization process. Shortly after refining and deodorizing, edible fats and oils are almost unoxidized and have a good flavor. However, it is conventionally known that edible fats and oils are oxidized by oxygen in the air, and as a result, the flavor deteriorates. In order to suppress the formation of compounds that are undesirable in the flavor of fats and oils due to the oxidation of such edible fats and oils, the purified fats and oils are generally stored at a low temperature.

  However, when edible fats and oils are stored at a low temperature, there is a problem that flavor deterioration called “return odor” may be caused even though oxidation does not proceed.

  Such flavor deterioration due to “return odor” becomes a problem in fish oil, soybean oil, rapeseed oil, hydrogenated oil, palm oil, and the like. The “return odor” has different odor characteristics and generation mechanisms depending on the type of edible oil and fat, and the causative substances of the “return odor” also differ. For example, the “return odor” of palm oil is generated specifically by exposure to low temperatures. It is also suggested that 2-nonenal is involved as one of the causative substances of “return odor”.

  Palm-based fats and oils, including palm oil, are harvested from Southeast Asia and then extracted and refined locally before being imported into Japan. Since this palm-based fat / oil is refined (degummed / deoxidized), decolorized, and deodorized, it is called RBD palm-based fat / oil (RBD = Refined Bleached Deodorized). RBD palm-based fats and oils imported by ordinary methods have undergone a refining process, but the oil color is dark and deteriorates somewhat during transportation, so the fats and oils contain peroxides and free fatty acids. Yes. For this reason, according to the quality of RBD palm oil and fat, it is common to re-refine so that it may meet the specification in Japan after import. As described above, since the re-refined RBD palm-based fats and oils may have a specific “return odor” during storage at low temperatures, a method capable of suppressing flavor deterioration has been desired.

  Then, as a method of solving such a problem, a method of adding 0.05 to 5.0% by mass of polysorbate to palm-based fats and oils has been proposed (Patent Document 1). In addition, a method has been proposed in which decolorization and deodorization are performed after contacting fats and oils with acetic acid, phosphoric acid, citric acid, or the like that is recognized as a food additive during the purification process (Patent Document 2). Furthermore, before the decoloring step, it includes a step of heating the glyceride composition under a temperature condition of 100 ° C. to 270 ° C. under reduced pressure, and the peroxide value in the glyceride composition after the heating step is set to 1 or less. A method has been proposed (Patent Document 3). Further, a method has been proposed that includes a step of decolorizing the raw glyceride composition while blowing 0.3% by mass or more of water vapor with respect to the total mass of the raw glyceride composition under reduced pressure conditions (Patent Document). 4).

JP 2005-168482 A JP 2006-28466 A JP 2013-28752 A JP2013-203962A

  However, the method described in Patent Document 1 in which polysorbate is added to palm-based fats and oils may not be practical because the use of the edible fats and oils produced may be limited due to the unique odor caused by the additives. It was.

  It is pointed out that the method described in Patent Document 2 requires an operation such as a contact operation with an acid solution or a dehydration operation, which increases the number of purification steps, leading to a decrease in production efficiency and an increase in cost. .

  It is pointed out that the method described in Patent Document 3 requires heating the edible fat / oil before decolorization and further cooling the temperature of the heated edible fat / oil to the decolorization temperature, leading to an increase in the number of steps. Moreover, if heating of edible fats and oils is not performed under nitrogen substitution or under vacuum, fats and oils will deteriorate, Therefore It is necessary to introduce the equipment for that and it was not necessarily easy.

  In the method described in Patent Document 4, there is a concern about reduction in the degree of vacuum at the time of decolorization, hydrolysis of triglycerides, reduction of the decolorizing ability of white clay used for decolorization, and the like by blowing water vapor.

  The present invention has been made in view of the circumstances as described above, and suppresses the generation of a return odor of edible fats and oils during storage at low temperatures easily and inexpensively without using special additives or manufacturing equipment. However, an object of the present invention is to provide a method for producing edible fats and oils that can produce edible fats and oils with less flavor deterioration.

  In order to solve the above-mentioned problems, the method for producing edible fats and oils of the present invention is characterized by including any of the following steps in the production of edible fats and oils.

(I) a step of bringing an adsorbent and an alkaline substance into contact with the oil to be treated in the coexistence (ii) a step of bringing an adsorbent having a pH of 5.0 or more into contact with the oil to be treated. Preferably, at least one of white clay and activated carbon is included.

  In this method for producing edible fats and oils, the alkaline substance is preferably an alkaline solution.

  In the method for producing edible fats and oils, the concentration of the alkaline solution is preferably 0.3% by mass or more and 25% by mass or less.

  In this method for producing edible fats and oils, the addition amount of the alkaline solution is preferably 1.0% by mass or more and 20% by mass or less with respect to the mass of the entire processing target oil.

  And in this manufacturing method of edible fats and oils, it is preferable that process target oil is RBD palm-type fats and oils.

  According to the present invention, the production of edible fats and oils with less flavor deterioration can be achieved without using special additives and production equipment, suppressing the generation of odors of edible fats and oils during storage at low temperatures and easily. Can do.

  The present invention is described in detail below.

In the method for producing edible fats and oils of the present invention, the refined oil obtained by refining the raw oil or the raw oil is used as the treatment target oil,
(I) a step of bringing an adsorbent and an alkaline substance into contact with the oil to be treated in the coexistence thereof; (ii) including any one of steps of bringing an adsorbent having a pH of 5.0 or higher into contact with the oil to be treated. .
<(I) Process>
The step (i) of the present invention is characterized in that the adsorbent and the alkaline substance are brought into contact with the oil to be treated in the coexistence thereof. As the adsorbent that can be used in the step (i) of the present invention, an adsorbent used in a normal oil refining process, particularly a decolorization process, can be suitably used. Activated clay, acidic clay, activated carbon, Examples include bentonite, silica gel, silica / alumina, aluminum silicate, diatomaceous earth, and the like. These adsorbents preferably contain at least one of clay and activated carbon. That is, the adsorbent can be used alone or in combination of two or more. In addition, in step (i), the pH of the adsorbent is not particularly limited. Even when an adsorbent having a pH of less than 5.0 is used, the generation of a return odor of the edible fat / oil is suppressed, and the edible fat / oil having less flavor deterioration is reduced. Can be manufactured.

Acid clay is mainly composed of a clay mineral called montmorillonite, and the pH and components differ depending on the production area. Moreover, the SiO ₂ content of the acid clay used in the present invention is preferably in the range of 65% to 85%, more preferably 68% to 75%. When the SiO ₂ content is within the above range, it is possible to suppress the occurrence of “return odor” of the edible oil and fat and to produce an edible oil and fat with less flavor deterioration. Examples of such commercially available acid clay include MIZUKA-ACE # 300 (pH 8.5, SiO ₂ content 70.5%, manufactured by Mizusawa Chemical Co., Ltd.), MIZUKA-ACE # 200 (pH 6.4, SiO ₂ content 71.0%, manufactured by Mizusawa Chemical Co., Ltd.).

The activated clay is an acid clay that has been subjected to an activation treatment in which sulfuric acid or hydrochloric acid is added and heated to increase the adsorption capacity. The SiO ₂ content of the activated clay used in the present invention is preferably in the range of 65% to 85%, more preferably 70% to 83%. SiO ₂ content is within the range described above, to suppress the generation of edible oils and fats return odor can be manufactured less edible oil flavored degradation. Examples of such commercially available activated clay include GALLEON EARTH V2 (pH 3.3, SiO ₂ content 79.8%, manufactured by Mizusawa Chemical Co., Ltd.).

  Activated carbon includes powdered activated carbon, charcoal, coconut shell charcoal, coal (lignite, lignite, bituminous coal, anthracite, etc.), oil, etc. made from sawdust, hard wood chips, charcoal (primary ash), peat (peat), etc. Examples thereof include granular activated carbon made from carbon, phenolic resin, etc., fibrous activated carbon made from rayon, acrylonitrile, coal pitch, petroleum pitch, phenolic resin, etc. as raw materials. In the present invention, the raw material and shape of the activated carbon are not particularly limited, but it is preferable to use powdered activated carbon because it can contact oil and fat more efficiently.

  These activated carbons can increase the adsorption capacity by applying an activation treatment. Examples of activated carbon activation methods include gas activation with water vapor, carbon dioxide, air, and combustion gas, and chemical activation with zinc chloride, phosphoric acid, and the like. Activated carbon can be classified into basic activated carbon activated at a high temperature of 500 ° C. or higher and acidic activated carbon activated at a relatively low temperature of less than 500 ° C. depending on the temperature during the activation treatment. The ash content of the activated carbon used in the present invention is preferably 3% to 7%, more preferably 4% to 6%. In addition, the activated carbon can be further improved in adsorption capacity by acid washing after the activation treatment.

  Examples of the alkaline substance used in combination with the adsorbent include alkali metal and alkaline earth metal hydroxides, carbonates, phosphates, organic acid salts, and alkoxide compounds. Specific examples include sodium carbonate, sodium bicarbonate, sodium methoxide, sodium ethoxide, calcium hydroxide, sodium hydroxide, potassium hydroxide, sodium tripolyphosphate and the like. In particular, sodium hydroxide is commonly used in the oil and fat refining process and is preferable.

  Such an alkaline substance is preferably dissolved in a solvent and used as an alkaline solution because it easily comes into contact with the oil to be treated. Examples of the solvent that can be used for dissolving the alkaline substance include water and alcohols such as methanol and ethanol. In particular, it is preferable to use water.

  The concentration of the alkaline solution is preferably in the range of 0.3 to 25% by mass, more preferably 1.0 to 20% by mass, and still more preferably 5.0 to 15% by mass. Illustrated. Moreover, as addition amount of an alkaline solution, Preferably it is 1.0 mass%-20 mass% with respect to process target oil, More preferably, the range of 1.0 mass%-10 mass% is illustrated.

  In addition, as a method of bringing the adsorbent and the alkali substance into contact with the oil to be treated, a method of adding the adsorbent in powder, particle, fiber state and the alkali substance to the oil to be treated and stirring and mixing, or adding an alkali substance Installed and fixed pelletized or fibrous adsorbent in a pipe that feeds the processed oil to be processed and formed into a cartridge, and the processed oil passes through the fixed adsorbent part. The method of contacting by is applicable.

  In the present invention, the adsorbent and the alkali substance only need to coexist at the time of contact with the oil to be treated, and the adsorbent and the alkali substance may be added to the oil to be treated at the same time. Although the other may be added after a certain time, it is preferable to add the other at the same time. It is also possible to prepare a mixture of an adsorbent and an alkaline substance in advance and contact the oil to be treated.

The amount of the adsorbent to be brought into contact with the oil to be treated is preferably 0.1% by mass to 20% by mass, more preferably 0.25% by mass to 10% by mass, and further preferably 0.5% with respect to the oil to be treated. The range of mass%-5.0 mass% is illustrated.
<(Ii) Process>
In the process (ii), the pH of the adsorbent is 5.0 or more.

  The adsorbent that can be used in the step (ii) of the present invention is not particularly limited as long as the pH of the adsorbent is 5.0 or more, and the adsorbent exemplified in the step (i) is used. It is possible. The adsorbent preferably contains at least one of clay and activated carbon, and the adsorbent can be used alone or in combination of two or more.

In addition, as the adsorbent having a pH of 5.0 or more of the present invention, acidic clay, basic activated carbon or the like can be used. In the acid clay used in the present invention, the SiO ₂ content is preferably 65% to 85%, more preferably 68% to 75%, and the pH is preferably the same as in the step (i). Examples are those having a pH of 6.0 or more, more preferably 7.0 or more, and even more preferably 8.0 or more. The basic activated carbon used in the present invention is preferably one having a pH of 6.0 or more, more preferably 7.0 or more, and even more preferably 8.0 or more. The ash content is preferably in the range of 3% to 7%, more preferably 4% to 6%, as in the step (i). Examples of commercially available products of such basic activated carbon include, for example, Umebachi IE stamped activated carbon (pH 9.7, ash content 4.4%, manufactured by Ohira Chemical Sangyo Co., Ltd.), NORIT HB PLUS (pH 10.1, ash content 7.0%). , Manufactured by Cabot Norit Japan Co., Ltd.).

  In addition, an adsorbent having a pH of less than 5.0 that has been previously subjected to an alkali treatment or the like to have a pH of 5.0 or more can be suitably used. Here, the alkali treatment includes a step of removing the solvent after mixing the adsorbent with the alkali solution.

  Examples of the alkali used for the alkali treatment include alkali metal, alkaline earth metal hydroxide, carbonate, alkoxide compound and the like. These can be used alone or in combination of two or more.

  As a solvent for dissolving the alkali, alcohol such as ethanol and methanol can be used in addition to water. These can be used alone or in combination of two or more.

  As a preferable density | concentration of an alkaline solution, the range of 0.1 mol / L-5 mol / L is illustrated, for example.

  The adsorbent can be recovered by filtering or centrifuging the mixed liquid of the adsorbent and the alkaline substance. The recovered adsorbent is washed with water, and the alkali-treated adsorbent is obtained through a solvent removal treatment step for removing residual free alkali.

  When the adsorbent is white clay, the pH is measured by the JIS K 5101-17-1: 2004 pigment test method. When the adsorbent is activated carbon, the pH is measured by the JIS K 1474: 2004 activated carbon test method.

  As a method of contacting the adsorbent with the oil to be treated, a powder / particulate adsorbent is added to the oil to be treated and mixed with stirring, or in a pipe or tank that feeds the oil to be treated. Alternatively, it is possible to apply a method in which a fibrous adsorbent filled with a cartridge is installed and fixed, and the processing target oil passes through the fixed adsorbent portion to come into contact with the adsorbent.

The amount of the adsorbent to be brought into contact with the oil to be treated is preferably 0.1% by mass to 20% by mass, more preferably 0.25% by mass to 10% with respect to the oil to be treated, as in the step (i). The range of mass%, More preferably, the range of 0.5 mass%-5.0 mass% is illustrated.
<Treatment target oil>
The oil to be treated is a refined oil obtained by subjecting a raw oil or a raw oil to one or more purification processes of degumming, deoxidation, decolorization, dewaxing and deodorization. In addition to those obtained by the method of obtaining oil from animal and vegetable oil species (pressing, extraction), raw oil is used for edible fats and oils or two or more kinds of edible fats and oils, such as hydrogenation, fractionation, transesterification, etc. that are usually performed in the field of edible fats and oils It may be a hydrogenated oil, a fractionated oil or a transesterified oil, or a triglyceride obtained by esterifying glycerin and a fatty acid. Further, each treatment such as degumming, deoxidation, decolorization, dewaxing and deodorization may be a treatment usually performed in the field of edible fats and oils.

The oil to be treated used in the present invention is not particularly limited as long as it is used as an edible oil and fat, and the form of liquid, solid, etc. at room temperature is not limited. Specific examples of oils to be treated include soybean oil, rapeseed oil, corn oil, sesame oil, perilla oil, linseed oil, peanut oil, safflower oil, safflower oil, sunflower oil, sunflower oil with high oleic acid, cottonseed oil, grape seeds Oil, macadamia nut oil, hazelnut oil, pumpkin seed oil, walnut oil, coconut oil, tea seed oil, sesame oil, borage oil, olive oil, rice bran oil, wheat germ oil, coconut oil, palm kernel oil, palm oil, cocoa butter, Examples thereof include animal and vegetable oils and fats such as algal oil, fish oil, milk fat, beef tallow and pork fat, and fractionated oils, hydrogenated oils and transesterified oils thereof. Examples of palm oils and fats include palm oil, palm fractionated oil, hardened oils thereof, transesterified oils and fats, etc., and these can be used alone or in combination of two or more. In addition, as a palm fractionation oil, a hard part, a soft part, a middle melting point part, etc. can be used. Moreover, when using hardened oil as palm oil fat, partially hardened oil, low temperature hardened oil, extremely hardened oil, etc. can be used. Among palm-based fats and oils, RBD palm-based fats and oils that have undergone a refining process have a relatively high purity, and can be suitably used as processing target oils in the present invention.
<Food additives>
The edible oil and fat obtained by the production method of the present invention can be processed and used as it is as a table and cooking oil. Moreover, you may provide to a market after adding a food additive as needed. The food additive is a component used in general edible oils, and examples thereof include emulsifiers, oxidation / deterioration inhibitors, crystal modifiers, spices, and coloring components. Examples of the emulsifier include glycerin fatty acid ester, polyglycerin fatty acid ester, sucrose fatty acid ester, polyglycerin condensed ricinoleic acid ester, sorbitan fatty acid ester, propylene glycol fatty acid ester, polyoxyethylene sorbitan fatty acid ester, organic acid monoglyceride, lecithin and the like. Illustrated. Examples of the oxidation / degradation inhibitor include tocopherols, ascorbic acid esters, flavone derivatives, kojic acid, gallic acid derivatives, catechins and esters thereof, fucic acid, gossypol, sesamol, terpenes, silicones and the like. Examples of the crystal modifier include triacylglycerol, diacyl glycerol, waxes, sterol esters and the like. Examples of spices include capsaicin, anethole, eugenol, cineol, gingerone and the like. Examples of the coloring component include carotene and astaxanthin.

  In addition, the edible oil and fat produced in the present invention has a good flavor, raw food (mayonnaise, dressing, whipped cream, ice cream, etc.), fried food (fried noodles, fried vegetables, etc.), fried food (tempura, croquette, tonkatsu, etc.) ), Spray heating cooking (cooking by spraying oil on ingredients and heating in an oven or microwave oven), etc., does not impair the flavor of the food to be cooked. Furthermore, even if it uses as an edible release oil, it can be used conveniently. The edible fats and oils produced in the present invention are preferably used for raw foods and the like stored at low temperatures because generation of a return odor during storage at low temperatures is suppressed.

  In the edible fats and oils obtained by the production method of the present invention, the return odor and the flavor deterioration of the fats and oils are suppressed.

  Therefore, according to the method for producing edible fats and oils of the present invention, it is possible to suppress the generation of a return odor of the edible fats and oils during storage at a low temperature and to provide edible fats and oils with less flavor deterioration.

EXAMPLES Hereinafter, although it demonstrates still in detail based on the Example of this invention, this invention is not limited to these Examples at all.
<Repurification of RBD palm oil>
The re-refining of RBD palm oil was performed along the following steps.

[Adsorbent / alkali treatment process]
420 g of RBD palm oil was dispensed into a 1 L four-necked flask and heated to 110 ° C. under a reduced pressure of 4000 Pa. In a flask, the process of Examples 1-15 mentioned later and Comparative Examples 1-4 was performed, and after stirring for 15 minutes, the adsorption agent and the alkaline substance were removed by filtration. In addition, Example 1-10 has shown process (i) and Example 11-15 has shown process (ii).

[Deodorization process]
400 g of the treated palm oil was dispensed into a 1 L four-necked flask and heated to 255 ° C. under a vacuum of 600 Pa. Deodorizing treatment was performed for 40 minutes while water vapor was blown into the flask. After the deodorization treatment, the palm oil was cooled, and when it reached 120 ° C., citric acid was added to 20 ppm. Furthermore, the said palm oil was cooled, and when it became 60 degreeC, it filtered using the filter paper, and obtained the deodorizing oil.

[Low temperature storage]
80 g of the palm oil after the deodorization was collected in a 100 mL screw mouth bottle and stored at 5 ° C.

Example 1
RBD palm oil, activated clay (GALLEON EARTH V2, hereinafter referred to as V2, pH 3.3, SiO ₂ content 79.8%, manufactured by Mizusawa Chemical Co., Ltd.), an alkali As a substance, 2.5% by mass of 10% (w / v) aqueous sodium hydroxide solution against oil was simultaneously added.

(Example 2)
15 minutes after adding 2.5 wt% of activated clay V2 as an adsorbent to RBD palm oil, 10% (w / v) aqueous sodium hydroxide solution as an alkaline substance was added to 2.5 wt% of oil. Added.

(Example 3)
To RBD palm oil, activated clay V2 of 2.5% by mass of oil as an adsorbent and 2.5% (w / v) aqueous sodium hydroxide solution of 2.5% by mass of oil as an alkaline substance were simultaneously added. .

(Example 4)
To RBD palm oil, activated clay V2 having 2.5% by mass of oil as an adsorbent and 5% (w / v) sodium hydroxide aqueous solution having 2.5% by mass of oil as an alkaline substance were simultaneously added.

(Example 5)
To RBD palm oil, activated clay V2 having 2.5% by mass of oil as an adsorbent and 10% (w / v) sodium hydroxide aqueous solution having 1% by mass of oil as an alkaline substance were simultaneously added.

(Example 6)
To RBD palm oil, activated clay V2 having 2.5% by mass of oil as an adsorbent and 1.5% by mass of 10% (w / v) sodium hydroxide aqueous solution having an amount of oil as an alkaline substance were simultaneously added.

(Example 7)
To RBD palm oil, activated clay V2 having 2.5% by mass of oil as an adsorbent and 10% (w / v) sodium hydroxide aqueous solution having 5% by mass of oil as an alkaline substance were simultaneously added.

(Example 8)
To RBD palm oil, activated clay V2 having 2.5% by mass of oil as an adsorbent and 10% (w / v) sodium hydroxide aqueous solution having 10% by mass of oil as an alkaline substance were simultaneously added.

Example 9
After simultaneously adding to the RBD palm oil an activated clay V2 of 2.5% by mass of oil as an adsorbent and a 10% (w / v) aqueous sodium hydroxide solution of 2.5% by mass of oil as an alkaline substance, 15 The mixture was stirred for a minute and filtered through filter paper to remove white clay and alkaline substances. After filtration, 2.5% by mass of activated clay V2 was further added to the oil.
(Example 10)
RBD palm oil, activated clay V2 with 2.5% oil by weight as adsorbent, and 5% (w / v) sodium tripolyphosphate with 3% by weight oil as alkali (sodium tripolyphosphate for food additives, Japan Chemical Industries, Ltd.) aqueous solution was added simultaneously.
(Example 11)
To RBD palm oil, 2.5% by mass of acid clay 1 (MIZUKA-ACE # 300, pH 8.5, SiO ₂ content 70.5%, manufactured by Mizusawa Chemical Co., Ltd.) as an adsorbent was added.

(Example 12)
To RBD palm oil, 2.5% by mass of acid clay 2 (MIZUKA-ACE # 200, pH 6.4, SiO ₂ content 71.0%, manufactured by Mizusawa Chemical Co., Ltd.) as an adsorbent was added.

(Example 13)
To RBD palm oil, 2.5% by mass of basic activated carbon (Umebachi IE marked activated carbon, pH 9.7, ash content 4.4%, manufactured by Ohira Chemical Industry Co., Ltd.) as an adsorbent was added.

(Example 14)
Add 200% by weight of 1% (w / v) sodium hydroxide aqueous solution to activated clay V2 in advance, stir at room temperature and pressure for 5 minutes, collect the clay by centrifugation, wash with water and remove residual free alkali. And then dried at 120 ° C. Activated clay V2 (pH 10.0) treated with the above alkaline solution of 2.5% by mass of oil as an adsorbent was added to RBD palm oil.

(Example 15)
To RBD palm oil, 1.25% by mass of acid clay 1 (MIZUKA-ACE # 300, pH 8.5, SiO ₂ content 70.5%, manufactured by Mizusawa Chemical Co., Ltd.) 25% by mass of basic activated carbon (Umebachi IE marked activated carbon, pH 9.7, ash content 4.4%, manufactured by Ohira Chemical Industry Co., Ltd.) was added simultaneously.

(Comparative Example 1)
To RBD palm oil, only activated clay V2 having 2.5% by mass of oil as an adsorbent was added.

(Comparative Example 2)
RBD palm oil was added with 10% (w / v) sodium hydroxide aqueous solution of 2.5% by mass of the oil as an alkaline substance, stirred for 15 minutes, filtered through filter paper to remove the alkaline substance, and activated clay. V2 was added at 2.5% by mass to the oil.

(Comparative Example 3)
15 minutes after adding 2.5% by mass of activated clay V2 to the RBD palm oil as an adsorbent, the mixture was filtered with a filter paper to remove the clay, and then 10% of 2.5% by mass of the oil as an alkaline substance. % (W / v) aqueous sodium hydroxide was added.

(Comparative Example 4)
To RBD palm oil, activated clay V2 having 2.5% by mass of oil and water having 2.5% by mass of oil were simultaneously added as adsorbents.
<Evaluation method>
(2-Quantification of Nonenal Production)
7g and 14th day after refrigerating storage, 1g of re-purified palm oil was dispensed into a headspace analysis vial, and volatile substances generated when heated at 80 ° C for 30 minutes were analyzed by solid-phase microextraction. It was collected at. This volatile substance was reheated at 250 ° C. for 4 minutes at the inlet of a GC / MS apparatus (GC 7890A MSD 5975C, manufactured by Agilent Technologies), and the volatile substance was removed from a column for gas chromatography (InterCap Pure-WAX, To GL Sciences). Subsequently, each component isolated in the column was detected with a detector to identify 2-nonenal, and then 2-nonenal preparation (purity 96.3) diluted with medium chain triglycerides (MCT). %, Manufactured by Tokyo Chemical Industry Co., Ltd.), the amount of 2-nonenal contained in each sample was quantified.

(Sensory evaluation of presence or absence of return odor)
7 days and 14 days after the start of refrigerated storage, the re-refined palm oil was heated to about 60 ° C., and a panel of 10 persons contained 1-2 mL with a dropper in the mouth, and sensory evaluation was performed. The presence or absence of a return odor at that time is 5 levels (5 points: no return odor is good, 4 points: no return odor is good, 3 points: some return odor is good, 2 points: return odor is felt, 1 The score was evaluated by the following criteria.

：: 4 points or more ○: 2.8 points or more and less than 4 points Δ: 1.5 points or more and less than 2.8 points ×: less than 1.5 points The results are shown in Tables 1, 2 and 3.

  As shown in Tables 1 and 2, in any of Examples 1 to 15, the re-refined palm oil 7 days after the start of refrigerated storage had a 2-nonenal amount of less than 100 ppb, and the results of the sensory test were also Good and no return odor was felt. In addition, the re-refined palm oil 14 days after the start of refrigerated storage has a 2-nonenal amount of less than 150 ppb in any of Examples 1 to 15, the sensory test results are good, and no return odor is felt. Even if a slight return odor was felt, the taste was not affected.

  From the results of Examples 1 and 2, the adsorbent and the alkaline aqueous solution were added at the same time, or the alkaline aqueous solution was added after the adsorbent was added, and the coexistence of the adsorbent and the alkaline aqueous solution was effective in reducing the return odor. It was shown that there is. On the other hand, even if the adsorbent and the alkaline substance were added as in Comparative Examples 2 and 3, the effect of reducing the return odor was not confirmed for those not in the coexistence.

  From the results of Examples 1, 3 and 4, it was shown that the higher the concentration of the alkaline solution added to the re-refined palm oil, the more effective the reduction of the return odor.

  From the results of Examples 5 to 8, it was shown that the more the amount of the solution added, the more effective the return odor is.

From the result of Example 10, it was shown that even if the alkaline substance is not strongly alkaline, it is effective for reducing the return odor.
From the results of Examples 11 to 14, it was shown that when the pH of the adsorbent is 5.0 or more, it is effective in reducing the return odor. It was also suggested that the higher the pH, the more effective the reduction of the return odor.

  From the results of Example 15, it was confirmed that the combined use of acidic clay and basic activated carbon was also effective in reducing the return odor.

  The comparison between Example 9 and Comparative Example 1 showed that the treatment with the adsorbent having an pH of less than 5.0 after the treatment of adding the adsorbent and the alkaline substance is effective in reducing the return odor.

  Furthermore, from a comparison between Example 1 and Comparative Example 1, it was confirmed that the addition of an adsorbent having a pH of less than 5.0 alone is not effective in reducing the return odor.

  From the comparison between Examples 1 and 2 and Comparative Examples 2 and 3, the activated clay V2 and the aqueous alkaline solution do not necessarily have to be added to the oil to be treated at the same time, but one is removed from the oil to be treated by filtration or the like and coexists. When the state could not be created, it was confirmed that it did not contribute to the reduction of the amount of 2-nonenal.

And from the result of the comparative example 4, even when the activated clay V2 and the water which is a solvent of an alkaline substance were added simultaneously, the reduction | decrease of 2-nonenal amount was not recognized.

Claims (5)

In the production of edible fats and oils, the following step (i):
(I) including a step of bringing the adsorbent and the alkaline solution into contact with the oil to be treated in the coexistence thereof,
The concentration of the alkaline solution state, and are 20 wt% or less 5.0% by mass or more,
The addition amount of the alkaline solution is 1.5% by mass or more and 20% by mass or less with respect to the mass of the entire processing target oil,
The method for producing edible fats and oils, wherein the oil to be treated in the step (i) is an RBD palm fat . The method for producing edible fats and oils according to claim 1 , wherein the adsorbent in the step (i) includes at least one of white clay and activated carbon. In the production of edible fats and oils, the following step (i):
(I) viewing including the step of contacting the adsorbent with an alkali solution to be processed oil in the presence,
The concentration of the alkaline solution is 5.0% by mass or more and 20% by mass or less,
The addition amount of the alkaline solution is 1.5% by mass or more and 20% by mass or less with respect to the mass of the entire processing target oil,
The process target oil in the said process (i) is RBD palm type fats and oils, The suppression method of the return odor of the edible fats and oils after low-temperature storage characterized by the above-mentioned. In the production of edible fats and oils, the following step (ii):
(Ii) it viewed including the step of contacting the pH8.0 more adsorbents to be processed oil,
The addition amount of the adsorbent is 0.1% by mass or more and 20% by mass or less with respect to the mass of the entire processing target oil,
A method for suppressing a return odor (excluding a return odor due to explosion) of edible oils and fats after low-temperature storage, wherein the oil to be treated in the step (i) is an RBD palm oil and fat. The adsorbent in the step (i) (ii) contains at least one of white clay and activated carbon, and the method for suppressing the return odor of edible fats and oils according to claim 3 or 4 .