NL8301786A - PROCESS FOR THE EXTRACTION OF DISACCHARIDES FROM TUBULAR CONTAINING DISACCHARIDES, USING AN EXTRACTION WITH UNHEATED WATER. - Google Patents

Abstract

Process for the recovery of disaccharides from disaccharides containing tuberous plants by mechanically reducing the tuberous plants to a mush, extracting the reduced material with water of less than 60 DEG C, subjecting the extract first to an ultrafiltration and then to a demineralisation and finally concentrating the obtained solution. In the process also mangels having a sugar content of 6-12% by weight can be used as starting material.

Description

NO. 31591

Method for recovering disaccharides from disaccharides containing tuberous plants, using extraction with unheated water.

Applicant mentions as inventors: Dr. K. Koerts and

Ir T.R. Hanssens

The invention relates to a process for preparing disaccharides from disaccharides containing tuberous plants, wherein a solution of disaccharide in water is first ultrafiltrated and then ion-exchanged.

Such a method, in which diffusion juice obtained by leaching sugar beet cut with warm (35 to 80 ° C) water, is subjected to ultrafiltration, passing through a cello tube surrounded by other untouchable tissue tubes, within a turbulent filtration of steel pipes is known from "Warenkennis 10 en Technologie" part 4, 81-87 (1957). All colloids are kept inside the tube without clogging the membrane and finally squeezed out of the tube. The sugar solution passes sterile, with all salts in it, through the membrane and escapes through a small opening at the bottom of the steel tube.

The sterile thin juice thus obtained can be completely freed from all salts with cation and anion exchangers, so that a solution is obtained which corresponds entirely to refined juice. By operating in this way, sugar is obtained without obtaining as a by-product molasses, which normally contains at least one sixth of the sugar from beet 20 and is inferior in comparison to sugar.

The colloidal products, which have been discarded separately, contain proteins, glutamic acid, threonine, proline and phenylalanine, which are worth more than molasses.

As far as is known, this known method is not applied on a technical scale.

However, as the sugar industry, which extracts sugar from sugar beets, is constantly confronted with increasing energy and wage costs, the following facets of the existing process are to be examined in order to promote more profitable exploitation: 30 a. Can be used for the limited shelf life of sugar beets, i.e. A solution is found 2 to 3 months, because the sugar content decreases with longer storage.

b. the extraction of the sugar from the root vegetable, in particular the sugar beet, can be carried out more advantageously.

8301786 f 2 c. extract and pulp can be separated more efficiently.

d. impurities can be removed to such an extent from the sugar solution that purification by crystallization of sugar from sugar solutions is no longer necessary.

5 ad.a.

proposals have been made many years ago to improve the shelf life of sugar beets, among other things by blowing cold air through them and / or drying beet cut and processing them in the course of 8 to 9 months. However, none of these proposals has yielded a solution that is technically and commercially acceptable.

ad.b.

It is common practice to cut the washed beet into thin strips (cossettes) and leach these strips with warm water. This stage of the process is decisive for the sugar loss balance. It is common practice to perform the extraction with countercurrent warm water. The sugar present in the juice of the cells of the sugar beet in dissolved form can only come out of the cells if the plasma is denatured with its semi-permeable skin or if the cell is mechanically opened. When the sugar beet is crushed in one way or another, not only is the sugar present in the cells dissolved during the extraction with warm water from the broken cells, but all kinds of other undesirable substances present in the cell are also dissolved. Examples thereof are proteins, salts, gums and polymers. This produces so many more problems during further processing than when cossettes are subjected to an extraction, that at present only beet cuttings are used for the extraction. When the beet is cut, a number of cells are destroyed, but the majority remains undamaged. In order to extract the sugar contained therein from the undamaged cells, the cells should be denatured and opened at elevated temperature. This change in structure is sometimes referred to as plasmolysis. Different phenomena occur depending on the temperature used. At 60 ° the protoplasm dies after contraction, while the denaturing takes place so rapidly with sudden rapid heating at 70 ° C. that the proteins remain largely in the original state and are, as it were, fixed.

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During the extraction, juice is first washed from the damaged cells. In addition, a lot of people are going into solution. In addition, since hydration water is released at the denature ring of the beet protein, which displaces juice, juice exits from the interior of the cut 5.

The major part of the substances present in the cut in dissolved form, in particular the sugar, then diffuses out of the coherent system of highly branched channels, which is available in the cellular tissue of the beet after the denaturing takes place before the dust exits. . Therefore, this method of extraction is referred to as a "diffusion process". A liquid exchange takes place in the denatured beet tissue, in which osmotic water enters through the small pores and a sugar solution emerges from the large pores through the hydrostatic pressure. In addition, the 15 small ions and molecules of substances other than sugar pass into the juice faster than the larger ions and molecules, and the behavior of the cations is also determined by the size of the anions. The electron neutrality of the anions diffuses only to such an extent that the diffusion potential is greater than the electric potential produced by the separation of the charges.

In connection with the plasmolysis, it is desirable to heat the cuttings as quickly as possible to 75 to 80 ° C. This prevents microorganisms from causing sugar losses by converting the sugar present.

At those high temperatures, the cellulose of the cell structure remains virtually unchanged, but the pectins swell and are even broken down in the long run. However, as the pectin content of the juice, the extract, increases, the processing of the juice becomes more difficult. In addition, temperatures that are too high due to the pectin conversion simultaneously cause a change in the cutting structure. The extortionability of the cut then deteriorates and the swelling process seals the capillary system in the cellular tissue of the cut. The fine channels become thinner and more or less closed, so that the exit of the sugar is slowed down and greater diffusion losses occur.

The extraction is therefore complicated and not optimal.

8301786 4 3.d (C · in order to separate the extract and the pulp as well as possible, the pulp is pressed at the end of the process, but in connection with the conversions in the beet tissue discussed under b), which occur from 5 inhibiting the sugar still present, up to now, no optimum separation could be achieved.

ad.d.

the water used for the extraction should be as pure as possible and, in particular, should not contain any solubles which affect the purification of the juice. A disadvantage is especially water containing alkali metal salts, because such salts prevent the crystallization of large amounts of sugar and thereby increase the unintended molasses yield.

In order to optimize the crystallization of the sugar during further processing, the raw juice is heated to 85 ° C and mixed with an excess of slaked lime. The free acids present thus form insoluble salts, which flocculate with many other impurities, for example proteins. Part of the lime forms calcium monosaccharate and another part dissolves. The slimy precipitate cannot be filtered off. Therefore, carbon dioxide and steam are introduced, which decomposes the saccharate and forms insoluble calcium carbonate with the dissolved lime, which can be filtered off.

After saturation and filtration twice, a thin juice is obtained containing about 15% by weight of sugar. This juice is thickened in a multistage process under reduced pressure until a saturated solution is obtained, which crystallizes out to the so-called. "Masse cuite" containing 86% sugar. In order to obtain a product with almost 100% sugar content, the "masse cuite" must be separated from the mother liquor by centrifugation, after which the described operation is repeated several times with the mother liquor. until the undesirable by-product of molasses remains.

It has been found that all the above-mentioned disadvantages or problems can be avoided or solved, respectively, by mechanically comminuting the disaccharide-containing tuberous crop, extracting the comminuted material with unheated water, then first with an ultrafiltration and then with a subject demineralization, and concentrate the resulting solution.

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By mechanically comminuting the tuberous crop, the sugar contained therein no longer needs to be extracted by diffusion, as is necessary with cutting, but the sugar present in the cells of the tuberous plant can be dissolved simply by washing out be rinsed from the cells disrupted by the mechanical treatment with unheated water.

Because unheated water is used, fewer non-sugar components are included here than in the extraction with warm water described under b). Therefore, some of the above-described purification operations can be omitted.

The mechanical crushing to a slurry can be carried out, for example, by grating with a grating device customary in the potato flour industry, an open impeller centrifugal pump or a shuttle mill, but preferably with the grating device mentioned.

15 After comminution, the beet juice and the beet pulp are separated.

This can proceed more efficiently than with the known method, since almost all cells are open during the crushing of the tuberous plant and no denaturing of unopened cells has taken place at elevated temperature. Suitable separation methods are: a. The use of a centrifuge sieve with a rotating basket in which the cell juice can be washed; b. application of a vacuum band filter; c. solid Bowl decanter with scroll.

The resulting solution is then ultrafiltrated, leaving all colloidal and undissolved components in the retentate. The permeate contains more sodium and potassium salts than thin juice, which is obtained according to the classical method, because an important part of the potassium and sodium salts that end up in the molasses in the classical process, now get into the permeate. To remove these salts, the permeate must be passed over an ion exchanger.

Preferably, the comminuted mass is first largely separated from the liquid contained therein and only then subjected to an extraction with water of at most 10 ° C.

The contact time during the extraction is not more than ½ hour, but such a contact time is seldom necessary because the extraction actually takes place at the first contact with water.

Furthermore, it is very important to choose the amount of water used for the extraction so that the sugar solution obtained has a sugar content of 12 to 14% by weight.

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An important advantage of the present process is still that the ultra-filtered, ion-exchanged and concentrated permeate is so pure that crystallization does not have to be crystallized in many steps in order to obtain substantially pure beet sugar and finally molasses are obtained as by-product. Of course, the concentrated solution can be concentrated to saturation and / or cooled, so that the sugar contained therein crystallizes, but this operation is not necessary for purification. Delivery of pure concentrated sugar syrup is also important for economic reasons because there are many technical applications of sugar where a concentrated solution must be assumed.

Another advantage is that in the present process no sugar-foreign substances are added to trigger certain reactions and to remove these substances again after the reaction has ended. The present method proceeds n.1. without addition of any reaction component.

It has been found that, in addition to the above advantages, the present method offers another important advantage, n.1. that so-called feed beets can be used as starting material instead of sugar beets.

For many decades beet sugar has been extracted from sugar beets with a sugar content of 16 to 19% by weight, by extracting the sugar beets with water as described above, then removing the pulp globally, then treating with lime and carbon dioxide to remove the pectin. - and to precipitate protein substances, subsequently separating the precipitate, concentrating the obtained juice (thin juice) by evaporation, crystallizing sugar from the saturated solution and separating the crystallized sugar.

Until now it has not been considered possible for economic and process technological reasons for the production of sugar to start from fodder beet with a sugar content of only 6 to 12% by weight. There could be n.1. it is expected that much more pulp would be obtained from the processing of fodder beet than from the processing of sugar beet.

The roots of fodder beets contain a lot of sodium, a lot of potassium, little magnesium and little calcium compared to the roots of sugar beet. As a result, the ratio K + Na to Mg + Ca is also much higher than with sugar beets. Detailed information on this can be found in "The distinction of sugar beet varieties based on the mineral composition of foliage and carrot" by P.J.H. van Ginneken, in "Announcements of 8301786 7 the Institute for Sugar Beet Cultivation", Bergen op Zoom, the Netherlands September 1940, and part IX - 1939 of the same institute.

As already stated above under "ad d", it is precisely the presence of many sodium and potassium ions in the sugar-containing extract in the processes which have been generally used until now that it is particularly disadvantageous for the process economy.

In addition, high potassium levels contribute to the formation of a lot of molasses.

However, the advantages of using fodder beets would be: 10 1) instead of payment for the sugar beet supplied, as is necessary and customary for sugar beets, if fodder beets are used as starting material, the price of the beet delivered could be determined only at hand by weight. The yield of fodder beet per field area unit is n.1. much greater than the yield of sugar beet per field area unit, making variations in sugar content less important; 2) using fodder beets as a starting material for the preparation of beet sugar, the process in the sugar factory could be better streamlined, because the shelf life of fodder beets is 20 months, while sugar beets can only be stored for 2 to 3 months. The "campaign" could therefore be extended to 7 to 10 months instead of about 3 months.

It is important in this context to provide some explanations regarding the differences between sugar and fodder beet.

25 Both types of beet originate from the Beta vulgaris beet. Several varieties have been developed from this original beet over the course of decades, with the properties aimed at the ultimate use. Two facets are more or less the opposite, i.e. the yield per unit area 30 and the sugar content.

Fodder beets or mangroves provide the highest beet yield per unit area and also the highest sugar yield per unit area, but the sugar content per beet is low, producing a lot of pulp as a by-product. They are usually not ripe until late and therefore have a lot of foliage at the time of harvest.

This type of beet makes better use of the soil's water supply than other types of beet. This makes them more resistant to long periods of drought. With the same amount of water and nutrients, they produce more dry matter than sugar beets. However, they are not suitable for the extraction of sugar according to the known method, because the amount of pulp obtained per unit weight of beet is considerably greater than when sugar beet is used and, moreover, the sugar content per unit weight of beet is much lower.

5 Sugar beets have a high sugar content, but produce less beet per unit area than fodder beet. Their amount of foliage at the time of harvest is much less than that of the original Beta vulgaris and the fodder beet, because they ripen early. They are better suited for sugar extraction than fodder beet because less pulp and more sugar can be obtained per unit weight of beet.

EXAMPLE I

Washed fodder beets were ground with a grater, such as that used in the potato-starch industry. The grater or slurry thus obtained was washed in a continuous multistage washing according to the countercurrent principle with water at 18 ° C and subsequently pulp and liquid were separated. This operation was performed with a solid-bowl decanter with scroll. Three such decanters were used in series, from the last (3rd) the desugared pulp, which was also centrifuged to 35% by weight dry matter. The latter decanter was fed with an already partially desugared second stage decanter pulp, which was mixed with pure water at 10 ° C. The amount of water was minimal because the countercurrent principle was used. That amount can be determined by calculating tolerance of a given sugar loss in the pulp when it is known that this third stage pulp is easily centrifuged to 35 wt% dry matter.

The same operation was repeated three times. From the first-stage decanter, cell juice was obtained, which was used to feed the ultrafiltration.

The first stage was fed with grater slurry mixed with dilute second stage cell juice.

In the ultrafiltration, a permeate and a retentate are obtained.

The retentate contained proteins, pectins and gums, which were mixed, for example, with the obtained desugared pulp with the obtained desugared pulp and sold as animal feed.

The permeate was further purified by passing it over ion exchangers and treating with decolorizing absorbents.

The very pure sugar syrup thus obtained is directly suitable for human consumption.

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EXAMPLE II

The slurry from the grater of Example I was desugared and dewatered using a multi-stage countercurrent wash in centrifuge sieves.

The desugared pulp was subsequently squeezed out in order to adjust the water content and therefore the sugar loss to an economically acceptable level.

The slightly diluted cell juice thus obtained was further worked up in the same manner as described in Example I.

Example III

1000 kg of fodder beet were ground into a slurry with a grater, such as is used in the potato-starch industry. This slurry was directly separated into 490 kg of pulp and 900 kg of cell juice in a centrifuge. It was washed with 390 kg of water at 9 ° C in order to desuginate the pulp as much as possible.

The slightly diluted cell juice was subjected to a combination of ultrafiltration. For the diafiltration, 90 kg of water at 9 ° C were added to dilute the 89 kg retentate of the first ultrafiltration and to desugarize to a large extent.

The final retentate only contained 1% by weight of sugar. The 900 kg mass of permeate or filtrate thus purified contained 9.7% by weight of sugar (polarimetric) and 13.4 (w / w)% of dry matter.

The invert sugar content was 5.4 (w / w)% based on the dry matter.

This purified juice was then demineralized successively using a canteen resin exchanger and an anion resin exchanger. This purified juice was almost colorless and contained only 5 (w / w)% non-sugar substances based on the dry matter content.

This juice was concentrated in an evaporator to 71 (w / w)% dry matter content. The white sugar obtained by crystallization was of excellent quality and was not inferior to other granulated sugar.

EXAMPLE IV

450 kg of fodder beets were reduced to pieces with a largest size of 8 cm using a cutting device. These pre-shredded pieces were fed through a screw pump to a homogenizer to grind the beet into a pulp.

This purée was then treated in the same manner as in Example III.

8301786 t 10

EXAMPLE V

600 kg of purée or grater (see examples III and IV) was desugared in a rapidly rotating sieve. The desugaring took place in four stages, the pulp mass flowing countercurrently with the juice.

The last stage pulp was desugared with 235 kg of water at 9 ° C. The centrifugation from this fourth stage was used to desugurize the centrifuged second stage pulp. This was done in the third stage. The centrifugate was passed to the centrifuged first stage pulp and the third stage pulp was passed to the fourth stage.

The mixture of centrifuges from the third stage and pulp from the first stage was dewatered in the second stage.

The second stage juice was combined with undiluted first stage cell juice. In this way, a slightly diluted cell juice 15 (520 kg) was obtained, which went to ultrafiltration for the first purification of proteins, gums and pectins.

The further work-up proceeded as described in example IV. With this, as in previous examples, a good quality of granulated sugar was obtained.

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Claims (5)

A method for recovering disaccharides from disaccharides containing tuberous plants, wherein a solution of disaccharides in water is first ultrafiltrated and subsequently ion-exchanged, characterized in that the tuberous plant is mechanically crushed, the comminuted material extract with unheated water and then first subject to ultrafiltration and then demineralization, and concentrate the resulting solution. 2. Process according to claim 1, characterized in that the tuberous plants that have been crushed by scraping are first largely separated from the liquid contained therein and only then subjected to an extraction with water of not more than 10 ° C. 3. Process according to claim 1 or 2, characterized in that a contact time of at most ½ hour is used in the extrusion with water of at most 10 ° C. 4. Process according to claims 1-3, characterized in that the amount of water used for the extraction is chosen such that the sugar solution obtained has a sugar content of 12 to 14% by weight. 20 Process according to Claims 1 to 4, characterized in that fodder beet with a sugar content of 6-12% by weight is used as the root vegetable 8301786