JPH078962B2 - Method for purifying carotene-containing concentrate - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for purifying a carotene concentrate by chromatography.

BACKGROUND OF THE INVENTION Carotene has wide application as an edible colorant or as a substance having a provitamin A action.

Carotene can be obtained by recovering carotene contained in synthetic or natural fats and oils. As a method for recovering carotene from a natural product, after saponifying a natural fat or oil containing carotene, a method of solvent-extracting carotene as an unsaponifiable product, by adding a lower alcohol to the natural fat or oil containing carotene, and subjecting to alcoholysis A method is known in which a fatty acid lower alkyl ester is produced, and this is distilled under reduced pressure to produce a fatty acid lower alkyl, which is then distilled under reduced pressure to concentrate carotene in the distillation residue.

Further, an oily substance containing carotene is brought into contact with and adsorbed on a styrene-divinylbenzene copolymer resin, and then contacted with alcohol to elute and separate the oily substance, and then a carotene easily soluble hydrophobic solvent is brought into contact therewith. A method for elution and separation of carotene has also been reported (JP-A-61).
-12657).

Further, the present applicant has conducted an alcoholysis of natural fats and oils containing carotene with a lower monoalcohol to collect an oil phase containing the produced carotene and having a fatty acid lower alkyl ester as a main component, and to the methanol phase in the oil phase. ,
A method has been proposed in which a hydrophilic solvent such as ethanol, isopropanol, and acetone and water are mixed to precipitate carotene for collection (Japanese Patent Application No. 59-236013).

The present invention is to further purify the carotene concentrate obtained by such various methods by chromatography.

Conventionally, as a method for purifying carotenes using chromatography, in high performance liquid chromatography for analysis, a method using calcium hydroxide as a packing material and a hexane / acetone mixed solvent as a developing solvent, and activated alumina as a packing material Only a method using hexane or a hexane / benzene mixed solvent whose water content is adjusted as a solvent has been studied, and no industrial examples have been found.

Generally, in analytical chromatography, the primary purpose is the degree of purification and quantification, and expensive packing materials and complicated mixed solvents are used to increase the degree of separation. When such an analytical method is scaled up as an industrial purification method, there are the following problems.

(1) Due to the small particle size of the packing material used, a large column causes a great pressure loss.

On the other hand, if the particle size is increased, the desired degree of purification cannot be obtained.

(2) The sample load is very small, and a large apparatus capacity is required to obtain a desired processing capacity.

(3) The time required for each batch is long.

(4) The amount of solvent used is enormous with respect to the sample.

OBJECT OF THE INVENTION The present invention provides an industrially useful method for purifying a carotene-containing concentrate by chromatography.

Constitution of the invention The method for purifying a carotene-containing concentrate of the present invention comprises supplying a carotene-containing concentrate to a filler for adsorption, and then supplying a developing solvent to the filler to elute and separate the carotene component, and a chromatographer. In the method for purifying a carotene-containing concentrate by chromatography, silica gel treated with acetone and hexane is used as the filler, and acetone is 0.005 to 1.0 wt% [50 to 10000 ppm (wt)] as the developing solvent.
It is characterized by using an acetone-hexane mixed solvent containing.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings.

FIG. 1 is a diagram for explaining the present invention, in which a column 11 is packed with silica gel pretreated with acetone and hexane. The particle size of silica gel is not particularly limited, but those having a particle size of 50 to 600 μm can be preferably used. According to the method of the present invention, a high degree of purification can be obtained even if the particle size of the silica gel filler is increased, so that a relatively large particle size can be obtained as described above, and the pressure loss is small and industrially advantageous. is there. When calcium hydroxide or activated alumina having a particle size of about 1 to 10 μm, which has been used as a filler in the conventional analysis method, is directly used in an industrial scale apparatus, the above-mentioned problems occur. On the other hand, silica gel is not only inexpensive, but can also efficiently purify carotenes with low pressure loss and high sample load.

The silica gel used is pretreated with acetone and hexane. By performing this pretreatment, it is possible to repeatedly perform purification treatment in a stable elution state. In this pretreatment, after silica gel was packed in the column 11, acetone was supplied to the column to be saturated and adsorbed on the silica gel, and then,
This can be performed by washing with hexane or a hexane / acetone mixed solvent, and ending the washing when the effluent has the same composition as the developing solvent.

The liquid to be treated containing the carotene concentrate is supplied to the column 11 filled with the pretreated silica gel by the feed pump 13 and adsorbed by the filler. As a carotene concentrate,
An oily substance containing carotene at a high concentration is used, and its origin is not particularly limited, but a natural fat or oil containing carotene such as palm oil is obtained by alcoholysis with a lower monoalcohol to obtain a carotene-containing fatty acid. Those obtained by increasing the carotene concentration by a suitable means such as extraction, adsorption, distillation or the like from a lower alkyl ester can be suitably used.

Such a carotene-containing concentrate is preferably diluted with hexane or a hexane / acetone mixed solvent. The dilution ratio is not particularly limited as long as there is no undissolved substance, but in order to shorten the sample supply time in the chromatography operation as much as possible, it is preferable to dilute to the saturated concentration of the carotene-containing concentrate in the solvent used. Is. When a hexane / acetone mixed solvent is used as the solvent, it is preferable to add 0.005-1.0% by weight of acetone.

Next, the feed pump 15 supplies an acetone / hexane mixed solvent as a developing solvent to elute and separate the carotene component. The amount of acetone added to the acetone / hexane mixed solvent is 0.005 to 1.0 wt% (50 to 10000 ppm), preferably 0.01 to 0.5 wt% (100 to 5000 ppm), more preferably 0.03 to 0.2 wt% (300 to 2000 ppm).

By using hexane as a developing solvent, carotene can be efficiently separated from other components such as fatty acid lower alkyl ester, and by adding a small amount of acetone, carotene can be purified while maintaining the degree of purification. The deployment speed of the part can be rapidly increased. As a result, the time required for each batch is shortened and the amount of solvent used is greatly reduced.

When the supply of the developing solvent is started, first, the substance having a lower polarity than carotene is eluted, and then the carotene part is eluted. After separating the carotene portion, the same developing solvent is continuously supplied to remove the component having a polarity higher than that of carotene from the column, and the operation of one batch is completed.

By repeating the above operation, the carotene concentrate can be industrially purified. The pretreatment of silica gel with acetone and hexane is performed only when new silica gel is filled, and thereafter, the above chromatography operation may be repeated.

Purified carotene is recovered from the separated liquid receiving tank / solvent recovery tank 17, and the solvent is recovered and recycled.

While the above-mentioned purification operation by chromatography is repeated, a highly polar substance that cannot be removed only by washing with the developing solvent gradually accumulates in the column, degrading the column performance. When carrying out purification by chromatography on an industrial scale, it is important to regenerate the contaminated packing material by a simple operation and repeatedly use it in order to reduce the manufacturing cost.

As a result of earnest studies to regenerate the contaminated silica gel, the present inventors have found that by firing the contaminated silica gel at a temperature of 400 to 800 ° C., the silica gel can be regenerated to a state before use and can be repeatedly used. FIG. 2 is a graph showing the relationship between the firing temperature and the apparent specific gravity of silica gel or the degree of carotene purification. At temperatures above 800 ° C, ash water due to dehydration of silica gel is seen, while
It cannot be completely regenerated below ℃. The contaminated silica gel is dried as it is or after being washed with acetone or the like, and then baked. If necessary,
After firing, the humidity is adjusted to adjust the silica gel to a predetermined water content.

The regeneration frequency of silica gel depends on the concentration of polar substances in the carotene concentrate to be treated.

The method of the present invention can be applied not only to the purification of carotene but also as a chromatographic purification method for trace components such as squalene, paraffin and tocopherol contained in natural fats and oils.

In addition, a method in which the packed column is pretreated so as to have an atmosphere similar to that of the developing solvent, chromatographic treatment is performed with the developing solvent, and then the column is washed with the developing solvent is a very simple operation. In addition, since it is possible to perform chromatographic purification and solvent recovery in a stable state, it is also suitable as a general chromatography operation method.

Effect of the Invention According to the present invention, silica gel treated with acetone and hexane was used as a filler, and hexane containing a small amount of acetone was used as a developing solvent, whereby a carotene-containing concentrate obtained from natural fats and oils was very stable. Repeated chromatographic purification can be performed in the elution state, and the development rate of the carotene part can be rapidly increased.
The time required per batch can be shortened, and the amount of solvent used can be significantly reduced. Furthermore, since the degree of purification does not decrease even if the particle size of the filler is increased to some extent, it is possible to efficiently purify carotenes with a low pressure loss and a high sample load. Depending on the conditions, a pressure loss of one-hundredth, a sample load of about 30 to 40 times, and a tenth amount of solvent used are compared to the case of simply scaling up conventional analytical chromatography. realizable.

If the carotene-containing concentrate is diluted with hexane or a hexane / acetone mixed solvent and a column washing solvent similar to the developing solvent is used, the solvent recovery system can be greatly simplified. The solvent recovered by distillation or the like can be reused as it is or as a developing solvent or a washing solvent with a slight composition adjustment.

Example 1 An apparatus as shown in FIG. 1 was dry-packed with spherical silica gel 2.5 having a particle size distribution of 50 to 600 μm, and then 150 g of acetone was supplied to this column. Furthermore, the column was washed with 15 hexanes, and it was confirmed that the acetone concentration in the effluent from the lower end of the column was 1000 ppm.

A crude palm oil containing a carotene concentration of 600 ppm (all converted to trans-β-carotene, the same applies below) is methyl esterified with methanol, and then extracted and concentrated with a methanol / water mixed solvent to give a carotene-containing concentrate containing 15% carotene. Got

75 g of this carotene-containing concentrate was diluted with 1425 g of hexane containing 1000 ppm of acetone and supplied to the above column. Then, hexane containing 1000 ppm of acetone was used for development, and fractionation was carried out from the time when the red part began to flow out from the lower end of the column until the end. The supply amount of the developing solvent at this time was 2.5 cm / min at the linear velocity based on the superficial column.

When the solvent was distilled off from the collected red solution under reduced pressure, 14 g of purified carotene having a carotene concentration of 72% was obtained. The carotene concentration was 4.8 times and the carotene recovery rate was 89.6%.

Example 2 Using the column used in Example 1, after eluting in the red part, 1000
After washing the column with hexane 7 containing ppm acetone, the same chromatographic operation as in Example 1 was carried out using 75 g of a carotene-containing concentrate (carotene concentration 15%) similar to that in Example 1 to obtain a carotene concentration. 15 g of 69.2% purified carotene was obtained. The carotene concentration was 4.6 times and the carotene recovery rate was 92.3%. The elution state of the red peak showed almost the same behavior as in Example 1.

Example 3 When the operations of Examples 1 and 2 were repeated, the carotene concentration in the purified carotene was reduced to 56% (the carotene concentration ratio was 3.7 times) by the 10th operation.

Therefore, the silica gel in the column was extracted, washed with 1 acetone, air-dried, and calcined at a temperature of 450 ° C. for 6 hours. Add moisture to the calcined silica gel to obtain a water content of 0.7.
%, And then packed in a column and purified by chromatography in the same manner as in Example 1. As a result, 14.4 g of purified carotene having a carotene concentration of 70.2% (carotene concentration ratio 4.7
The recovery rate of carotene was 90.0%, and the function of silica gel was completely restored.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a chromatography device used in the present invention. FIG. 2 is a graph showing the relationship between the firing temperature and the apparent specific gravity of silica gel or the degree of carotene purification.

Claims (1)

[Claims] 1. A carotene-containing concentrate by chromatography in which a liquid to be treated containing a carotene-containing concentrate is supplied to a filler to be adsorbed, and then a developing solvent is supplied to the filler to elute and separate the carotene component. In the purification method, silica gel pretreated with acetone and hexane is used as the packing material, and acetone is 0.00
A method for purifying a carotene-containing concentrate, which comprises using an acetone-hexane mixed solvent containing 5 to 1.0% by weight.