JPH07197076A - Refinement of crude edible oil - Google Patents

Abstract

PURPOSE:To refine a crude edible oil economically advantageously by simply and effectively reducing the amount of the adsorbent used in a decolorization step by adding sulfuric acid and phosphoric acid to a crude edible vegetable oil and simultaneously effecting the separation of soap and the removal of a chlorophyll pigment in an alkali refining step. CONSTITUTION:This refinement process comprises adding a combination of sulfuric acid with phosphoric acid as the acid used in the acid treatment in a step of refining a crude edible vegetable oil with an aqueous alkali solution, and simultaneously effecting the separation of soap and the removal of a chlorophyll pigment in the alkali refinement step.When sulfuric acid alone is used as the acid, the formed soap is small in particle size and is light, therefore can be insufficiently separated and is apt to be emulsified in the subsequent step of water washing, which causes poor workability. When a combination of sulfuric acid with phosphoric acid is used as the acid, the soap grows in K large particle size and can be separated in markedly improved workability.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an alkaline deoxidizing step in which sulfuric acid and phosphoric acid are used together as an acid in the decomposition and removal of chlorophyll pigments in edible plant crude oil, particularly in the acid treatment of the deoxidizing step using an alkaline aqueous solution. The present invention relates to a method for refining edible plant crude oil, which removes chlorophyll-based pigment decomposition products as well as soap separation. The acid treatment as used herein means an edible plant crude oil that has undergone a degumming process of removing a hydrophilic gum substance that is precipitated by hydration of crude edible plant oil that has been extracted from oil seeds by pressing and / or extraction. As a quality, it refers to a treatment in which an oil-soluble gum substance is made hydrophilic by using various acids capable of chelating a metal in impurities such as phosphatide dissolved in a state of being bound to a metal in fats and oils to facilitate separation. Conventionally, acids such as phosphoric acid, acetic acid, citric acid, oxalic acid, maleic acid, tannic acid and tartaric acid have been used for this purpose. At this time, the addition amount of the acid is appropriately changed according to the amount of the oil-soluble gum substance remaining in the crude oil to prevent the emulsification of the free fatty acid soap generated by the alkali neutralization and to make the state of the best separability. It is common to use an amount suitable for.

[0002]

2. Description of the Related Art Up to now, refined edible plant oils containing a large amount of chlorophyll pigment have not only a strong green color and low commercial value, but are also susceptible to deterioration during storage due to sunlight, fluorescent light, etc. In refining crude oil, it was an important technique to remove this chlorophyll dye more economically and as much as possible.

[0003] As a method therefor, it is common to remove a coloring component in edible plant crude oil by adsorbing it on an adsorbent such as activated clay in a decoloring step of finishing to a light color.

[0004]

In the treatment by active clay adsorption in the conventionally known decolorization process, the larger the amount of chlorophyll pigment contained in the edible plant crude oil, the more the amount of the adsorbent used and the cost increase. Moreover, there is a drawback that the amount of white clay increases and industrial waste increases.
There has been a need for a purification method that removes chlorophyll-based dyes without causing these drawbacks.

On the other hand, 1) a method for removing pigments such as chlorophyll by decolorizing in two steps of activated clay and activated carbon in order to reduce the amount of the adsorbent used in the decolorization step (Japanese Patent Laid-Open No. Sho 5).
6-21554), 2) A method in which concentrated sulfuric acid is added and mixed before the deoxidation step to precipitate 90% or more of the chlorophyll-based dye, which is removed and then washed with hot water (Patent Publication 1-
No. 50357) has been proposed.

However, in the method 1), the more the amount of the chlorophyll-based pigment contained in the deoxidized oil, the more the amount of the adsorbent used does not change, and the treatment of the waste clay and the activated carbon after treatment is greatly improved. Don't In the method 2), the degummed crude oil is treated with concentrated sulfuric acid immediately before entering the deoxidation step using an aqueous alkaline solution, and the precipitate is separated and removed by centrifugation or the like, followed by washing with hot water to remove the chlorophyll-based pigment. Although it has an advantage of reducing the load of the adsorbent treatment in the decolorization step, this step involves the steps of centrifugation and washing with hot water, which complicates the processing and causes a change in equipment and a decrease in work efficiency. In the hot water washing step, oil and warm water form a viscous emulsion, and separation of oil and water becomes extremely difficult, which may make work impossible. Furthermore, if the time-consuming separation in this hot water separation step becomes severe, the decomposition of tocopherols in the oil becomes severe, and there are many problems such as the possibility of causing the quality deterioration of the refined oil.Therefore, a simpler method is required. It was

The object of the present invention is to remove chlorophyll-based pigments in edible plant crude oil by overcoming such problems and removing chlorophyll-based pigments easily and effectively without adding complicated steps. Then, the adsorbent used in the decolorization process is reduced to provide a method for refining edible plant crude oil which can reduce the amount of industrial waste and improve the product yield.

[0008]

In order to solve the above problems, the inventors of the present invention have conducted extensive studies, and as a result, in the acid treatment in the deoxidation step using an alkaline aqueous solution of edible plant crude oil,
The present invention has been completed based on the finding that the combined use of sulfuric acid and phosphoric acid as the acid can effectively separate the soap component in the alkaline deoxidizing step and at the same time effectively remove the chlorophyll dye.

That is, according to the present invention, in the acid treatment in the deoxidation step using an alkaline aqueous solution of edible plant crude oil, a mixed acid of sulfuric acid and phosphoric acid or sulfuric acid and phosphoric acid are individually added and used in combination to stir the crude oil to obtain a chlorophyll-based compound. This is a method for refining edible plant crude oil, which is characterized by firstly decomposing a pigment and further decomposing it by neutralizing with an alkali to remove chlorophyll-based pigment together with free fatty acid soap produced by alkali.

In the present invention, the acid may be added by mixing sulfuric acid and phosphoric acid in advance during acid treatment (mixed acid), or by adding sulfuric acid and phosphoric acid separately. When the acids are added individually, either sulfuric acid or phosphoric acid may be added first, but sulfuric acid is preferably added first. The amount of sulfuric acid added to the edible vegetable crude oil is not particularly limited, but is preferably 0.05% or more, and an appropriate amount is added according to the concentration of the chlorophyll-based pigment in the oil. The amount of sulfuric acid to be added varies somewhat depending on the type of crude oil and the like. For example, if the content of chlorophyll-based pigment in crude oil is 30 ppm or less, 0.05% or more to about 0.1%, or 30 to 50 ppm is 0. 1 to 0.2%, 50 to 70 ppm is 0.
2 to 0.3%, 0.3 to 70 to 100 ppm
It is recommended to increase the amount to 0.5%.

Conventionally, acids such as phosphoric acid, acetic acid, citric acid, oxalic acid, maleic acid, tannic acid and tartaric acid have been used as an acid treatment, but when these are used, the effect on the removal of chlorophyll dyes is extremely high. Few or almost none.

[0012] For example, most of chlorophyll contained in rapeseed seeds is converted into pheophytin from which magnesium atoms are removed and dissolved into oil during the oil pressing process. Sulfuric acid, which is a strong acid, acts on the pheophytin to cleave the lipophilic phytyl group bound to pheophytin and convert it to hydrophilic pheophorbide. Pheophorbide is further changed by the subsequent alkali treatment and decomposed into a substance that can be easily removed, or it is adsorbed by the free fatty acid soap and removed as it is.
According to the present invention, chlorophyll contained in other edible plant crude oils is similarly changed and removed.

In the case of the present invention, an edible vegetable crude oil at 30 to 60 ° C. is treated with an alkaline aqueous solution in an acid treatment in a deoxidizing step by adding an appropriate amount of 0.05% or more of concentrated sulfuric acid and an appropriate amount of phosphoric acid. Stir for ~ 60 minutes. After that, an alkali is added and neutralized according to a conventional method to separate and remove free fatty acid soap.
At this time, the chlorophyll-based dye can also be effectively removed at the same time.

In the case of using sulfuric acid alone, the soap particles formed are fine and light, so that the separation and removal of soap is insufficient, and it is easy to form an emulsion in the subsequent washing step,
Affects workability. By using sulfuric acid and phosphoric acid in combination, soap particles grow large, separation becomes easy, and workability is greatly improved. At this time, sulfuric acid and phosphoric acid may be mixed in advance and then added, or they may be added separately.
Phosphoric acid is added in the optimum amount that has been generally used in the past, but the addition ratio of sulfuric acid is adjusted by the chlorophyll-based pigment content of edible plant crude oil.

If the amount of sulfuric acid added is less than 0.05%, the effect of removing the chlorophyll dye is small, and if the amount added is too large, the quality of the finishing oil is adversely affected.
% Or more is added within a range that does not adversely affect the quality of oil.

The present invention is applicable to oil seeds (soybean, rapeseed, corn, sunflower, cottonseed, safflower, sesame, rice bran, etc.) and edible plant crude oil extracted from pulp (palm).

[0017]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited to the gist of the present invention.

Example 1 Degummed rapeseed crude oil obtained by degumming rapeseed crude oil obtained by pressing and extraction from rapeseed seeds and having different chlorophyll-based pigment contents (crude oil A: 6.5 pp)
m, crude oil B: 35.4 ppm, crude oil C: 42.6 pp
m, crude oil D: 54.8 ppm) with various amounts of 98
% Concentrated sulfuric acid and 75% phosphoric acid 0.1% were added, and the mixture was stirred at 40 ° C. for 40 minutes, and then alkali deoxidized according to a conventional method.
By adding sulfuric acid in an amount suitable for the chlorophyll content in crude oil in addition to phosphoric acid, the chlorophyll-based pigments after the deoxidation step of the four crude oils were reduced to about 1 ppm. Further, the soap particles produced during alkaline deoxidation had larger soap particles and were separated more quickly than those produced during the conventional treatment. The amount of soap remaining in the deoxidized oil was 33 ppm.

Comparative Example 1 Various kinds of 98% concentrated sulfuric acid were added to the four kinds of degummed rapeseed crude oil used in Example 1, and the same treatment as in Example 1 was performed thereafter. By adding sulfuric acid in an amount suitable for the chlorophyll content in crude oil, the chlorophyll-based pigments after the deoxidation step of the four types of crude oil were reduced to about 1 ppm. However, the soap particles were difficult to separate into small pieces. Therefore, the amount of soap remaining in the deoxidized oil was as high as 230 ppm.
Was about 7 times.

Comparative Example 2 Various amounts of 75% phosphoric acid were added to the four kinds of degummed rapeseed crude oil used in Example 1, and the same treatment as in Example 1 was performed thereafter. The chlorophyll-based pigments after the deoxidation step of the four types of crude oil were hardly reduced regardless of the amount of phosphoric acid added. However, the soap particles were large and separated rapidly. The amount of soap remaining in the deoxidized oil was 30 ppm, which was about the same as in Example 1.

Table 1 shows the separated state of the soaps obtained in Example 1 and Comparative Examples 1 and 2 and the content of the chlorophyll pigment after deoxidation.

[0022]

[Table 1]

Example 2 98 for the four types of degummed rapeseed crude oil used in Example 1
% Concentrated sulfuric acid 0.14% and 75% phosphoric acid 0.1%,
After stirring at 40 ° C. for 40 minutes, alkaline deoxidation was performed according to a conventional method. Due to the difference in the chlorophyll pigment content of the crude oil, the chlorophyll pigment content of the oil after deoxidation also differed from 0.1 to 1.1 ppm.

Table 2 shows the chlorophyll dye content after deoxidation according to Example 2.

[Table 2]

EXAMPLE 3 Crude oil B in Example 1 was treated with 98% concentrated sulfuric acid 0.14% and 75% phosphoric acid 0.1% to obtain a deoxidized oil of 1.5%.
% Of activated clay was used for decolorization treatment according to a conventional method, and then deodorization treatment was performed to obtain a deodorized finished refined oil. The quality levels of the obtained deodorized finished refined oil, such as flavor, oxidation stability, and heat resistance, which must be provided as an edible oil, were the same as those of ordinary products.

Comparative Example 3 Crude oil B was treated with 98% concentrated sulfuric acid 0.14% in Comparative Example 1 and decolorized with 1.5% activated clay according to a conventional method. After that, deodorization treatment was performed to obtain a deodorized finished refined oil. The quality level of the refined deodorized finished refined oil such as flavor, oxidative stability and heat resistance, which must be provided as an edible oil, was the same as that of ordinary products.

Comparative Example 4 The decolorized oil obtained by treating Crude Oil B with 75% phosphoric acid 0.14% in Comparative Example 2 was subjected to a decolorization treatment using 1.5% of activated clay according to a conventional method. After that, deodorization treatment was performed to obtain a deodorized finished refined oil. The refined oil obtained had a high chlorophyll content even in the deodorized finished refined oil, and exhibited a deep green color.

With respect to the rapeseed decolorized oil and the deodorized finish refined oil produced in Example 3 and Comparative Example 3, the chlorophyll pigment content and the like were measured. The results are shown in Table 3. The decolorized rapeseed oil and the refined deodorized refined oil produced in Comparative Example 4 also showed similar values.

[0029]

[Table 3] Note) The deoxidized oil of Comparative Example shows the value of that obtained in Comparative Example 1.

[0030]

As is clear from the above results, the present invention enables effective removal of chlorophyll pigments in the deoxidation step of edible plant crude oil refining. By this, when removing chlorophyll-based pigments in edible plant crude oil, it is possible to remove chlorophyll-based pigments easily and effectively in the current deoxidation step without adding a complicated step, and adsorption in the decolorization step It is possible to provide an economical method for refining edible plant crude oil, which greatly reduces the amount of the agent used.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kou Ha 1-7-40 Oiwake, Shimizu City Shizuoka Prefecture Honen Corporation Co., Ltd. (72) Inventor Natsuko Ichikawa 809-2 Oka, Shizuoka City, Shizuoka Prefecture

Claims (4)

[Claims] 1. In the acid treatment of an edible plant crude oil in a deoxidizing step using an alkaline aqueous solution, sulfuric acid and phosphoric acid are used together as an acid, and soap is separated in the alkaline deoxidizing step to remove a chlorophyll pigment. A method for refining edible vegetable crude oil. 2. The method for refining edible plant crude oil according to claim 1, wherein sulfuric acid and phosphoric acid are premixed and used during the acid treatment. 3. The method for refining edible plant crude oil according to claim 1, wherein sulfuric acid and phosphoric acid are individually added and used together during the acid treatment. 4. The edible plant according to claim 1, wherein the amount of sulfuric acid added to the edible plant crude oil is 0.05% or more, and an appropriate amount is added according to the concentration of the chlorophyll-based pigment in the oil. Crude oil refining method.