JPH07197075A - Refinement of crude edible vegetable oil - Google Patents

Abstract

PURPOSE:To refine a crude edible vegetable oil economically advantageously by simply and effectively reducing the amount of the adsorbent used in a decolorization step by adding sulfuric 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 sulfuric 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. According to this process, a suitable amount (>=0.05%) of concentrated sulfuric acid is added to a crude edible vegetable oil of 30-60 deg.C, and the resulting mixture is agitated for 10-60 min. An alkali is then added to the mixture to neutralize it, and the formed free fatty acid soap is separated. A chlorophyll pigment also can be removed effectively and simultaneously. When the amount of the sulfuric acid added is 0.05% or below, the effect of removing a chlorophyll pigment can not be attained, whereas, when this amount is excessive, the quality of the finished oil is adversely affected.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention uses sulfuric acid as an acid in the decomposition and removal of chlorophyll-based pigments in edible plant crude oil, especially in the acid treatment in the deoxidation 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 separating soap in an alkaline deoxidizing step. The acid treatment referred to here is an edible vegetable crude oil that has been subjected to a degumming step of removing a hydrophilic gum substance that is precipitated by squeezing and / or extraction of edible vegetable crude oil from oil seeds, and an oil-soluble gum. 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]

BACKGROUND OF THE INVENTION 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 also are susceptible to deterioration during storage due to sunlight, fluorescent light, etc. It was an important technique to purify the chlorophyll-based dye more economically and as much as possible in the purification.

[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. In addition, the amount of white clay will increase and the amount of industrial waste will increase. 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 the advantage of reducing the load of adsorbent treatment in the decolorization process, the process of centrifugation and hot water washing is added to this process, which complicates the process, changes equipment, and lowers work efficiency. In the washing process, oil and hot water form a violent emulsion, which makes separation of oil and water extremely difficult, which makes work impossible. Furthermore, if it takes time in this hot water separation step, the decomposition of tocopherols in the oil will become severe, and it is expected that it will cause deterioration of the quality of the refined oil.
There are many problems such as the above, and a simpler method has been demanded.

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 inventors have found that the use of sulfuric acid as an acid allows the chlorophyll-based dye to be effectively removed at the same time as the separation of the soap component in the alkaline deoxidizing step, and has completed the present invention.

That is, according to the present invention, in the acid treatment of the deoxidation step using an alkaline aqueous solution of edible plant crude oil, sulfuric acid is added to stir the crude oil to primarily decompose the chlorophyll-based pigment, and further decompose by alkali neutralization. This is a method for refining edible plant crude oil, which is characterized by removing chlorophyll pigments together with free fatty acid soap produced by alkali. The amount of sulfuric acid added to edible vegetable crude oil is 0.05%
As described above, the chlorophyll-based pigment is characterized by being added in an appropriate amount according to the concentration in the oil. The amount of sulfuric acid to be added is 0.05% or more, preferably around 0.1%, and 30% if the content of chlorophyll pigment in the crude oil is 30 ppm or less.
If ~ 50ppm, 0.1-0.2%, 50-70ppm
If it is 70 to 100 ppm, the amount should be increased sequentially to 0.3 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.

For example, most of the chlorophyll contained in rapeseed seeds is converted into pheophytin from which magnesium atoms have been removed in the oil pressing step and dissolved in the oil. 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 deoxidation step by adding an appropriate amount of 0.05% or more of concentrated sulfuric acid to give 10 to 6
Stir for 0 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.

The amount of sulfuric acid added is adjusted depending on the chlorophyll-based pigment content of edible plant crude oil.
If the amount is less than the above, the effect of removing the chlorophyll-based dye is not provided, and if the amount added is too large, the quality of the finishing oil is adversely affected.

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).

[0015]

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 pigment contents (crude oil A: 6.5 ppm,
Crude oil B: 35.4 ppm, crude oil C: 42.6 ppm, crude oil D: 54.8 ppm) was added with various amounts of 98% concentrated sulfuric acid, and the mixture was stirred at 40 ° C. for 40 minutes, and then alkali-treated according to a conventional method. Deoxidation was performed. By adding sulfuric acid in an amount suitable for the chlorophyll content in crude oil, the amount of chlorophyll-based pigments after the deoxidation process of four types of crude oil was reduced to about 1 ppm.

Comparative Example 1 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 crude oils were hardly reduced regardless of the amount of phosphoric acid added.

Table 1 shows the content of the chlorophyll dye after deoxidation according to Example 1 and Comparative Example 1.

[Table 1]

Example 2 98 for the four types of degummed rapeseed crude oil used in Example 1
% Concentrated sulfuric acid 0.14% was added, the mixture was stirred at 40 ° C. for 40 minutes, and then alkali 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 The decolorized oil obtained by treating crude oil B with 98% concentrated sulfuric acid 0.14% in Example 1 was subjected to a decolorization treatment using 1.5% activated clay. 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 2 The decolorized oil obtained by treating crude oil B with 75% phosphoric acid 0.14% in Comparative Example 1 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 deodorized oil also had a high chlorophyll content and a dark green color.

Table 3 shows the measurement results of the chlorophyll-based pigment content and the like of the rapeseed decolorized oil and deodorized finished refined oil produced in Example 3 and Comparative Example 2.

[0024]

[Table 3] Note) The deoxidized oil was obtained in Example 1 and Comparative Example 1.

[0025]

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.

Front Page Continuation (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 (2)

[Claims] 1. An edible plant characterized by removing sulfuric acid as an acid in the acid treatment of an edible plant crude oil using an aqueous alkaline solution in the deoxidation process to remove soap and chlorophyll-based pigment in the alkaline deoxidation process. Crude oil refining method. 2. 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. Refining plant crude oil.