JPH0231758B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Technical Field) The present invention relates to an industrially advantageous method for removing diglyceride components contained as impurities in fats and oils, and more specifically, diglyceride components that adversely affect the stability and physical properties of fats and oils. Natural animal and vegetable oils, synthetic oils and fats, or processed oils and fats thereof, especially fractionated oils obtained by solvent fractionation, are brought into contact with an alkaline solution in a low polar solvent to effectively remove these components with good yield. Regarding the method. (Prior Art) Various methods have been developed to separate hard butter fractions from raw material fats and oils rich in 2-unsaturated-1,3-disaturated triglycerides by means such as solvent fractionation. Raw material fats and oils are deoxidized and then subjected to fractionation in order to obtain a good crystalline state and increase the fractionation yield. Therefore, conventional hard butter fractions obtained by solvent fractionation all have low acid values, but even if such hard butter fractions are subjected to normal refining treatments including deacidification treatment, However, it contains diglyceride components. Such diglyceride components adversely affect the physical properties of a cacao substitute fat, such as deteriorating the stability of the fat and oil, and in particular worsening tempering properties when a hard butter fraction containing this component is used as a cacao substitute fat. This has already been reported in the literature (JAOCS
(62), 2 , 421-425 (1985), Chem.Phys.Lipids,
25, 179 (1979), etc.). As described above, in the past, small amounts of diglyceride components could not be removed by normal purification processes including degumming, deacidification, decolorization, and deodorization steps. In recent years, as a method for removing diglyceride components contained in raw materials that are particularly susceptible to quality deterioration, for example, Japanese Patent Publication No. 57-35759 describes a method in which fats and oils are passed through a column filled with alumina, silica gel, etc. to adsorb and remove the components. is proposed.
However, in such a method, columns and adsorbents are expensive to use, and operations such as filling the column with the adsorbent, adsorption treatment, and desorption and cleaning of the adsorbed substance are complicated. (Problems to be Solved by the Present Invention; Objectives) As described above, the present invention aims to industrially advantageously remove diglyceride components contained as impurities in fats and oils. (Means for Solving Problems; Structure) As a result of intensive research in view of the above points, the present inventors found that a fraction obtained by contacting a caustic soda aqueous solution with unremoved hard butter fraction Micella obtained during hexane fractionation. It has been found that when the oil is used as a cacao substitute fat, the diglyceride component is removed to the extent that it does not have any adverse effects.
The present invention was completed based on this knowledge. That is, the present invention focuses on saponifying and removing the diglyceride component by contacting miscella obtained by dissolving an oil or fat containing a diglyceride component and having an acid value of 5 or less in a low polar solvent with an alkaline aqueous solution. This is a method for removing the diglyceride component inside. The present invention will be explained in detail below. The fats and oils to be treated in the present invention may be any oils such as natural animal and vegetable oils, synthetic oils, or fractionated oils thereof, and are not particularly limited. It is preferable to have one. If the acid value is too high, it will be difficult to selectively saponify and decompose diglyceride components and triglyceride components, and the effect will tend to decrease. Micella is obtained by dissolving these fats and oils in a solvent. The solvent is preferably a low polar solvent such as petroleum ether, hexane, heptane, octane or nonane, especially hexane.
A highly polar solvent such as acetone is not preferred because it reduces the selectivity of saponification and decomposition and also produces impurities. The concentration of micellar is 1 part by weight of oil/fat in solvent.
A solution concentration of 0.02 to 5 parts by weight, preferably 0.1 to 2 parts by weight, may be sufficient. If the amount of the solvent is less than the lower limit, the polarity of the micella becomes high and the selectivity of saponification and decomposition between the diglyceride component and the triglyceride component deteriorates.
That is, if the amount of solvent is small or if no solvent is present, the triglyceride itself will be saponified and decomposed by the alkali. Since the present invention is carried out in a low polar solvent, the diglyceride component is distinguished from the triglyceride component and is selectively treated with an alkali to be saponified and decomposed. Moreover, if the amount of solvent exceeds the upper limit, it is economically disadvantageous in that the reactivity of saponification decreases and a large amount of solvent is used.
The amount of alkali is determined by the neutralization equivalent of free fatty acids contained in the target fat and the saponification equivalent of diglyceride components.
It is best to use a total amount of 1.0 to 20 times the amount. If it is less than the lower limit, sufficient saponification cannot be achieved, and if it is too much, there is a risk that triglycerides will be saponified and decomposed, which not only reduces the yield but also makes post-treatment difficult, which is not preferable. Further, the concentration of the alkaline aqueous solution is preferably 1 to 70% by weight, preferably 10 to 20% by weight. As the alkali, sodium hydroxide, which is generally used for deoxidizing treatment, is suitable. In the present invention, the contact between the miscella and the alkaline aqueous solution can be carried out at a temperature of 50 to 130°C, but the higher the temperature, the faster the rate of saponification and decomposition.
It is appropriate to conduct the reaction at a temperature of 70 to 120°C. If the process is carried out at normal pressure, a reflux condenser is attached to collect the evaporated solvent, but the
℃ is the limit, and raising the temperature higher than this is dangerous because the solvent will evaporate rapidly, and there is a risk that it will not be able to be recovered sufficiently and may escape into the atmosphere. From the standpoint of environmental hygiene, the escape of the solvent into the atmosphere should be avoided as much as possible, and it is preferable to conduct the reaction in a closed system (under pressure) even at low temperatures. Thus, depending on the amount of alkali and the concentration of micella, after contacting with the alkaline aqueous solution under normal pressure or closed pressurization for about 10 to 30 minutes at 60 to 70°C and 3 to 5 minutes at 100 to 110°C, the micella is removed. Separate the foots. Separation can be carried out by centrifugation, but if the alkali concentration is high and in small amounts, the foots can also be separated by simple filtration.
Refined oil is then obtained by recovering the solvent from the miscella. In particular, the present invention can be carried out in the micellar state as it is without removing the solvent from the fraction during hexane fractionation, and the yield is considerably improved, so it is an extremely advantageous method economically and industrially. can. In this case, carry out fractionation treatment under specific conditions experimentally in advance and measure the neutralization equivalent of the alkali required to neutralize the free fatty acids in the fraction and the saponification equivalent of the alkali required to saponify the diglyceride component. Bye. The former is determined by measuring the acid value, and the latter is determined by thin layer chromatography (JAOC).
S. (62), 2 , 421-425 (, 85)) or high-performance liquid chromatography (Fette Seifen Anstric
hmittel, 85 , 274-278 (, 83)) The amount of alkali required can be easily determined by analysis. (Effects of the Invention) As described above, the present invention makes it possible to easily saponify and remove the diglyceride component contained as an impurity in fats and oils by contacting miscella prepared by dissolving fats and oils in a low polar solvent with an alkaline aqueous solution. According to the present invention, the storage stability of fats and oils is improved, and a hard butter fraction with excellent quality can be obtained. (Examples) Examples and comparative examples will be illustrated below to further clarify the effects of the present invention, but these are merely illustrative and the present invention is not limited by these examples. Example 1 1 part by weight of deacidified palm oil with an acid value of 0.2 was added to 4 parts by weight of hexane.
The high melting point portion was separated and removed at 0°C, and the mixture was further cooled to -12°C to obtain a crystalline portion of the middle melting point fraction. When a part of this crystal part was desolventized and measured, the acid value was 0.13, and the diglyceride component was
The yield of the intermediate melting point fraction was 23.1% by weight, calculated from the iodine values before and after the fractionation. Next, this crystal part was heated and melted at approximately 110°C under sealed pressure (oil content: 32.7% by weight).
0.02 parts by weight of a 12.7% by weight aqueous sodium hydroxide solution per 1 part by weight of micella (total amount of neutralization equivalent of free fatty acid and 1.2 times the saponification equivalent of diglyceride component)
Gradually add the mixed solution to 110% while stirring vigorously.
The temperature was maintained at 0.degree. C. for 5 minutes. Thereafter, the mixture was cooled to 40° C., filtered to separate the hexane solution portion, and the hexane was recovered to obtain a palm mid-melting point fraction at a yield of 21.7% by weight based on the fractionated raw material. The thus obtained fraction had a diglyceride component content of 0.9% by weight,
It was very good as a hard butter ingredient. Comparative Example 1 In Example 1, 0.06 parts by weight of a 12.7% by weight sodium hydroxide aqueous solution (free fatty acid (total amount of neutralization equivalent and 1.2 times the saponification equivalent of diglyceride component)
was gradually added, and the mixed solution was kept heated at 70°C for 5 minutes while stirring vigorously. Then, centrifugation was performed to obtain a medium melting point fraction with a yield of 21.0% by weight based on the fractionated raw material. This fraction had a diglyceride component content of 3.1% by weight. Example 2 1 part by weight of deoxidized sal fat having an acid value of 1.3 was dissolved in 3 parts by weight of hexane under heating, and the low melting point part was separated and removed at -20°C to obtain a stearin crystal part. When a part of this crystal part was desolventized and measured, the acid value was 1.4 and the diglyceride component was 2.8% by weight, but TLC analysis revealed that it contained 5.2% by weight of other polar components. (The yield calculated from the iodine values before and after fractionation was 75.2% by weight.) Next, this crystal part was placed in a container equipped with a reflux condenser and melted at 65°C. (Oil content: 50.2% by weight) ) 1 part by weight of 16.9% by weight aqueous sodium hydroxide solution
0.047 parts by weight (total amount of the neutralization equivalent of the free fatty acid and 4 times the saponification equivalent of the diglyceride component) was gradually added with vigorous stirring, and the mixture was heated and maintained at 65° C. for 15 minutes. Thereafter, it was cooled to 40°C, centrifuged to separate the hexane solution portion, and the hexane was recovered to obtain monkey fat stearin at a yield of 67.7% by weight based on the fractionated raw material. When the monkey fat stearin thus obtained was analyzed, the diglyceride component content was 0.6.
% by weight, and the content of other polar components by TLC analysis was as low as 3.4% by weight. This result is
This is thought to be because the polar substances were selectively decomposed or easily transferred to foots by the low polarity hexane. Comparative Example 2 In Example 2, 16.9% by weight was added to 1 part by weight of the fat (acid value 1.4, diglyceride component 2.8% by weight, and other polar components 5.2% by weight) obtained by removing the solvent from a part of the crystalline part. Sodium hydroxide aqueous solution 0.094
Parts by weight (total amount of the neutralization equivalent of the free fatty acid and 4 times the saponification equivalent of the diglyceride component) were gradually added, and the mixture was kept heated at 80° C. for 5 minutes with vigorous stirring. Thereafter, it was centrifuged to obtain monkey fat stearin at a yield of 54.8% by weight based on the fractionated raw material.
The diglyceride component content of this product is 1.9% by weight, and other polar components are 4.2% by weight by TLC analysis.
It was hot. Example 3 0.5 parts by weight of hexane was added to 1 part by weight of palm soft oil having an acid value of 0.2 and an iodine value of 60.4, with a diglyceride component content of 18.2% by weight, heated to 90°C in a closed container, and then 12.7% by weight. 0.185 parts by weight of an aqueous sodium hydroxide solution (total amount of the neutralization equivalent of the free fatty acid and 1.1 parts by weight of the saponification equivalent of the diglyceride component) was gradually added with vigorous stirring, and the mixture was kept heated for 5 minutes. Thereafter, it was centrifuged to obtain purified oil with a yield of 90.4% by weight. The diglyceride component content of this palm soft oil was 3.2% by weight. Comparative Example 3 After heating 1 part by weight of the same palm soft oil used in Example 3 to 80°C, 0.185 parts by weight of a 12.7% by weight aqueous sodium hydroxide solution (neutralization equivalent of free fatty acid,
A total of 1.1 parts by weight of the saponification equivalent of the diglyceride component) was gradually added with vigorous stirring, and the mixture was heated for 5 minutes. The mixture after completion was in an emulsified state, and when centrifuged, the yield was 40.2% by weight, which was a rather poor yield. The diglyceride component content of this palm soft oil was 8.2% by weight. When the respective palm soft oils obtained in Example 3 and Comparative Example 3 were heated with hydrolysis and the acid value was measured after 24 hours, the former was 1.1 and the latter was 1.6. It showed good stability.

Claims (1)

[Claims] 1. Micella obtained by dissolving an oil or fat containing a diglyceride component and having an acid value of 5 or less in a low polar solvent is brought into contact with an alkaline aqueous solution to saponify and remove the diglyceride component. , a method for removing diglyceride components from fats and oils. 2. Claim 1, wherein the low polarity solvent is a single or mixed solvent of hydrocarbon compounds such as petroleum ether, hexane, heptane, octane, nonane, etc.
The method described in section. 3 Micella contains 0.02 parts of low polar solvent per 1 part by weight of oil and fat.
3. The method according to claim 1 or 2, which is a solution dissolved in ~5 parts by weight. 4 Micella contains 0.1 part of low polar solvent per 1 part by weight of oil and fat.
4. The method according to any one of claims 1 to 3, wherein the method is a solution in which 2 parts by weight are dissolved. 5 The amount of alkali is equal to the neutralization equivalent of free fatty acids contained in the fat and oil and the saponification equivalent of the diglyceride component.
The method according to any one of claims 1 to 4, wherein a total amount of 1.0 to 20 times the amount is used. 6. The method according to any one of claims 1 to 5, wherein the alkaline aqueous solution has a concentration of 1 to 70% by weight. 7 The contact temperature between micellar and alkaline aqueous solution is 50~
The method according to any one of claims 1 to 6, wherein the temperature is 130°C. 8. The method according to any one of claims 1 to 7, wherein the contact between the micella and the alkaline aqueous solution is carried out in a closed system.