WO1999023260A1 - Method for processing vegetal raw materials in order to produce pentose hydrolysates essentially containing xylose - Google Patents

Abstract

The present invention relates to a method for producing pentose hydrolysates from pentosane-containing raw materials which have a higher purity as well as a higher xylose content. This method can be used for increasing the xylite production rate and comprises processing the hydrolysate in the following manner. This method uses as pentosane-containing raw materials the distiller's grain from the brewers' industry. During a first step, the distiller's grain having a natural humidity is submitted to a liquid-phase disintegration in a disc mill comprising a vibrator with an oscillation frequency of between 10 and 50 Hz. The disintegration can also be carried out in an ultrasonic apparatus with waves at a frequency of between 22 and 44 kHz or in a rotary-pulse apparatus having a rotor rotating at 3000 r/min., wherein the disintegration is carried out for a duration of 1 to 15 minutes and the solid phase is further separated from the liquid suspension. A second step comprises carrying out a high-temperature scrubbing during which the solid phase is mixed with water according to a ratio of 1 : 5-8. The mixture is maintained at a temperature of between 140 and 160 °C for 10 to 30 minutes while being periodically stirred. The solid phase is then separated and submitted to hydrolysis using a 0.5-2.5 % solution of sulphuric acid for a duration of between 2 and 4 hours and at a temperature of between 100 and 120 °C. This method ensures the protection of the pentosanes against the acidic decay during the refining process of the vegetal raw materials. The xylose concentration relative to the total amount of sugars in the hydrolysate increases from 57 % (when the starting mixture is distiller's grain) to 84-87 %, while the arabinose content is divided by two (from 30 to 13-17 %). This method further produces a proteinic paste containing up to 40 % of raw proteins while maintaining the nutritional values of the distiller's grain components.

Description

SPΟСΟБ ПΕΡΕΡΑБΟΤΚИ ΡΑСΤИΤΕΕΗΟГΟ RESOURCES FOR THE PΟΕΕΗΗΕΕΤΟZΗYΧ HYDΡΟLIZΑΤΟΒ, SΟDΕΡΑSHCHI, PΡΕΜUSCHΤΒΕΗΗΟ, ΚSILΟZU.

TECHNICAL FIELD. 5 The invention relates to the field of processing plant materials, in particular pentosan-containing raw materials, by hydrolysis to obtain sugar solutions and their subsequent use, for example, to obtain xylitol.

Plant-based pentosane-containing raw materials are the only source of xylose and xylitol, valuable products that are used as sugar substitutes for the nutrition of patients with diabetes. It has also been established that xylite has a preventive and therapeutic effect on dental caries. Toothpaste and chewing gum recipes are based on xylite. 5 The scale of using xylitol as a sugar substitute for food, medical and other purposes is constantly increasing. The technology for obtaining xylitol (pentavalent alcohol) is based on the ability of xylans of the original raw materials in the presence of mineral acids to hydrolyze to monosaccharides, which upon subsequent hydrogenation give the corresponding polyatomic alcohols. The increase in the yield of xylitol from pentose-containing raw materials depends on the xylose content in the pentose hydrolysate, as well as on its quality.

PΡΕΧΕΤΒCOMFORTABLE ΡΟΒΕΗБ ΤΕΧΗIΚI. The technological process for obtaining food xylitol can be divided 5 into the following main stages: mechanical preparation and chemical refinement of pentosan-containing raw materials, two-stage pentosan-hexose hydrolysis of raw materials and subsequent processing of the obtained sugar solution for obtaining xylitol. At present, in xylitol production, two types of vegetable pentosan-containing raw materials are used to obtain a solution of xylitol - cotton seed husks (cotton husks) and cob cores corn (corn cob). Birch wood is a promising type of raw material.

At the first stage of the process, the raw materials are mechanically prepared, crushed, sorted, and biologically degradable. At the second stage, chemical refinement of the raw material is carried out, which includes low-modulus wetting of the raw material with an acid solution, followed by percolation extraction of water-soluble impurities with water or diluted sulfuric acid. temperature of about 100°C with a hydromodule equal to 2. The duration of acid-water enrichment of raw materials is 2-4 hours.

The final operation that determines the quality of the pentose hydrolysate and the yield of xylitol is the hydrolysis of hemicellulosic polysaccharides of pentazane-containing raw materials. Pentose hydrolysis of refined crushed corn cobs is carried out at 120-150 °C for 60 minutes at 2% sulfuric acid content inside the hydrolyzed particles at a capillary-absorbed liquid modulus of 2-2.3. The concentration of ΡΒ in this mode is 6.2-7.5% and the content in the hydrolyzate is 70 - 75% of pentose sugars οτ General content of monosaccharids. (Yu.I. Kolkin Technology of hydrolysis, production. M. Forest Industry, 1989, pp.385 - 392)

The main components of the pentose hydrolysate are monosaccharides, primarily ϋ-xylose, which is converted into xylitol as a result of catalytic reduction. The content of ϋ-xylose in the hydrolysate when using corn cob cobs as the feedstock is 65-78% of the total.

A method is known for processing cotton husks to obtain pentose hydrolysates with their subsequent use for obtaining xylitol (E.K. Klimova "Method for increasing the efficiency of the pentose hydrolysis process" journal "Hydrolysis and forest chemical industry", Ν° 7, 1980 sτρ. 4-7). The flake husk has the following chemical composition, %: Easily hydrolyzable polysaccharides (EHP) - - 25.0

Hydrogen-resistant polysaccharides (HRP) - - 34.0

Lignin - - 30.0 Ash matter - 2.5

Pentosans - 20.4

Hexosans - 34.4

Non-carbohydrate components - - 8.5

The process of hydrolysis of pentosans and removal of sugars from hydrolyzed raw material of cotton husk was carried out according to the following method. The flaxseed husk was moistened with a 10% solution of sulfuric acid (hydrogen modulus 0.2-0.3) at a temperature of 20-25 °, after which impurities were extracted with water at a temperature of 80-100 ° C for 60 minutes. Pentose hydrolysis was carried out with 1.5% sulfuric acid. acid at a temperature of 120°C. The pentose hydrolysate was characterized by the following parameters:

Concentration ΡΒ, % 6.5

Quality of hydrolysate, % 64.5

(Content of pentosaccharides in hydrolysate)

Yield of pentose, relative to the mass of dry material, % 20.0

The specified quality of the obtained pentose hydrolyses is achieved due to the conduction of acidic acid. processing of 5 pentasant de-depleting materials, also at the same time taking part of the pentases Sakhanov.

POSSIBILITY OF IZOBΡΕΤΕΗIYA.

The invention is aimed at creating a method for obtaining pentose hydrolysates from pentosan-containing raw materials, having increased quality and increased xylose content, which ensures an increased yield of xylitol during subsequent processing of the hydrolysate. The method consists in using beer distillate, which is a waste product of beer production, as a pentose-containing raw material.

At the first stage of the process, the beer mash of natural moisture is subjected to disintegration for 1-15 minutes in excess water at a temperature of 25 - 45 °C, and then the solid phase is separated from the liquid suspension using, for example, a screw press.

For disintegration, a disk mill with a vibration frequency of 10 - 50 Hz, or an ultrasonic installation with a wave frequency of 22 and 44 kHz, or a rotary-pulsation device with a rotor rotation frequency of 3000 rpm are used. The technical effect is achieved in any of the indicated disintegration variants

In the process of implementing the method, a liquid suspension is formed, which is a paste enriched with protein, containing up to 35% protein, and a solid phase with a moisture content of 40-50% is enriched with fiber, which has the appearance of a fibrous mass.

At the second stage of the process, high-temperature washing is carried out, during which the solid phase is mixed with water in a ratio of 1: 5 - 8, maintained with periodic stirring for 10-30 minutes at a temperature of 130 - 160 ° C, followed by by separating the solid phase, which is then subjected to hydrolysis with a 0.5 - 2.5% sulfuric acid solution for 2 - 4 hours at a temperature of 100 - 120 °C.

Beer mash is a waste product of beer brewing production and is formed as a result of using crushed barley malt during brewing of beer wort. For 100 kg of produced wort 115-130 kg of wet mash are obtained. Depending on the method of extraction from the beer wort, the beer wort has a mushy appearance from liquid to crumbly with a weakly expressed bready odor from light yellow to brown in color [TU-10-5031536-135-90]. Beer mash contains about 32% of easily hydrolysable polysaccharides (EHP) and 11% of hardly hydrolysable polysaccharides (HP). In addition, beer mash contains ash, lignin, non-carbohydrate components, including protein, fat, wax. The literature provides information on the use of beer flour as an additive to flour in the production of bakery products, feed in dairy farming, compost, after processing by microorganisms, and also as a source of energy - biogas. Known, for example, is a method for producing protein-rich proteins from dry milkweed (Patent ΦΡГ 1677670, Α 23 K 1/06, 1977)

To obtain feed containing 15% by weight of protein, dry beer mash is subjected to gentle grinding or crushing to release protein from the fibers, then sifted through a sieve. The protein content can be increased to 30% by finer grinding.

There is a known method for processing the brewing dopant (Patent ΦΡГ Νз 2403203, Α 23 K 1/06, 1976), which consists in In that case, the entire volume is divided by auger into dessicated and sour (liquid), which contains a large amount of fibers. The juice is separated by means of a vibrating screen into fibers, which are returned to the pressed pellet and used as coarse feed and liquid containing a small amount of fibers. This liquid is divided into a liquid fraction that can be used in the food industry, for example for kneading dough, and a protein-rich flour paste. A method for obtaining protein-enriched products (US Patent No. 5135765 A 23 K 1/10, 1992) consists of mixing wet beer grains with 77.5% moisture content with water and passing them through a roller mill at a roller speed of 100 rpm. The water mixture sieved through a sieve with a mesh size of 0.4-1 mm. After repeating the above operations 0 times, the fibrous material and protein material with a protein content of 50.8% are extracted. The literature does not contain any information on the use of beer distillate as a pentose-containing raw material for the production of pentose hydrolysates containing xylose.

It should be noted that, unlike traditional types of pentose-containing raw materials, beer mash is characterized by a high content of non-carbohydrate components. Thus, 80% of the protein taken from grain processing remains in the brewer's mash, since the breakdown of protein substances in the grain under the action of enzymes in the beer production process is only 20%. Therefore, during acid hydrolysis, necessary for the dissolution of pentosans, proteins disintegrate into amino acids, which form intensely colored condensation products with sugars, called melanoidins. This leads to a deterioration in the quality of the hydrolysate and reduces the yield of useful target products - xylose (xylitol) and protein. Mechanical refinement of raw materials ensures the removal of the bulk of impurities that hinder the implementation of subsequent stages of the technological process of xylitol production.

At the first stage, the initial raw material is disintegrated in the liquid phase using a disk mill (DM), an ultrasonic unit (UZ) or a rotary pulse apparatus (RPA), and under the conditions of "wet grinding" the destruction of cellular walls, which increases the efficiency of extraction of non-carbohydrate impurities from raw materials: protein, fats, wax, pectins, minerals and other substances. At the same time, the process of disintegration of beer mash should not be accompanied by strong depletion of the cell walls of the raw material, which leads to significant losses of pentosans with the separated liquid suspension (protein paste).

The liquid suspension squeezed on the press is enriched with the above-mentioned valuable components, therefore it is sent for subsequent use, for example, in the food industry. when baking bread, preparing feed for farm animals and other purposes.

The solid phase is subjected to high-temperature washing (HTW), as a result of which an additional amount of non-carbohydrate impurities passes into the liquid phase, which are then separated with the washing liquid.

The washed solid phase is enriched with hemicellulosic polysaccharides, which are then hydrolyzed with dilute acid to obtain high-quality pentosic hydrolysate. The choice of modes of disintegration of beer mash is determined by the need to ensure the most complete separation of non-carbohydrate impurities from raw materials with minimal mechanical destruction of fiber. This allows to minimize the loss of raw material pentosans with the separated non-carbohydrate components of the beer mash, and also to minimize the process of protein denaturation, which contributes to the preservation of their biological nutritional value.

The selected conditions of high-temperature aqueous treatment of disintegrated raw materials allow, along with the remains of non-carbohydrate components, to transfer into the solution about 50% of arabinose, which is an impurity product in the production of xylitol, which is associated with selective destruction under conditions of autocatalytic hydrolysis of arabinose-containing side chains of xylane molecules.

The choice of hydrolysis modes with dilute sulfuric acid is determined by the need for quantitative transfer of pentosaccharides into the solution.

The invention is explained by similes. ΒΑΡIΑΗΤY ΟDUSHΕSΤΒLΕΗIYA IZΟΡΕΤΕΗIYA. PΡIΜΕΡ 1.

Beer sludge with natural moisture content (75-80%), having the following composition: easily hydrolyzable polysaccharides (EHP) - 32.2%, hardly hydrolyzable polysaccharides (HP) - 11.0%, lignin 16.5%, 8

ash matter 5.6%, proteins 19.2%, fats and waxes 8.5%, others 7.0%, hexosans 14.3%, pentosans 28.9%, subjected to wet grinding in a RPiδsι ΡiΙνΕζζΚΕ disc mill for 3 min. at a vibrator oscillation frequency of 25 Hz. After this, the mass is separated in a screw press to obtain a solid phase of 40-50% moisture and a liquid suspension. The phase ratio and cathode characteristics are presented in Table 1. (All indicators are given in absolute dry weight of the material).

Table 1.

At the second stage of the process, high-temperature washing (HTW) of the fibrous mass is carried out at a phase ratio (solid: liquid) of 1:6. Holding is carried out with periodic stirring for 10 minutes at 160°C. After that, the leading phase is separated from the suspension, the phase relationship and the chemical reactions are presented in the table. 1, and carry out hydrolysis of the solid phase with a 2% sulfuric acid solution at a temperature of 100°C for 3 hours at a hydromodulus of 10. The obtained hydrolysate contains the following sugars (see Table 7).

The total sugar content in the hydrolysate is 4.4%, while (from the total concentration of sugars) the amount of xylose is 70%, arabinose - 18%, galactose - 9% and glucose - 2%. The quality of the hydrolysate sent for subsequent processing into xylitol is 84.5%.

PRIMER 2.

The beer mill according to example 1 is subjected to wet grinding in a disc mill for 5 minutes at a vibration frequency of 40 Hz. After this, the mass is separated in a screw press to obtain a solid phase and a liquid suspension. The phase ratio and cathode characteristics are presented in Table 2. (All indicators are given in absolute dry weight of the material).

Table 2.

10

10

At the second stage of the process, high-temperature washing of the fibrous mass is carried out at a phase ratio (solid: liquid) of 1:5. Holding is carried out with periodic stirring for 10 minutes at 160°C. After that, the leading phase is separated from the suspension, the phase relationship and the chemical reactions are presented in the table. 2, and carry out hydrolysis of the solid phase with a 2% solution of sulfuric acid at a temperature of 100°C for 3 hours at a hydromodulus of 10.

The obtained hydrolysate contains the following sugars (see Table 7). The total sugar content in the hydrolysate is 4.8%, while (from the total concentration of sugars) the amount of xylose is 71%, arabinose - 16%, galactose - 11% and glucose - 2%. The quality of the hydrolysate sent for subsequent processing into xylitol is 87%. POIΜΕΡ 3. Beer trough with 1 double ultrasonic processing with the name apapate UZDK-1, Operating in the wave range of 22 and 44 kHz. The work was carried out on hydraulic module 8 for 10 minutes. (frequency 22 kHz, power 0.6Α). After this, the mass is separated in a screw press to obtain a solid phase with 40-50% moisture and a liquid suspension. The phase ratio and cathode characteristics are presented in Table 3. (All indicators are given in absolute dry weight of the material).

11

Table 3.

At the second stage of the process, high-temperature washing of the fibrous mass is carried out at a phase ratio (solid: liquid) of 1:6. Holding is carried out with periodic stirring for 10 minutes at 160°C. After that, the leading phase is separated from the suspension, the phase relationship and the chemical reactions are presented in the table. 3, and carry out hydrolysis of the solid phase with a 2% solution of sulfuric acid at a temperature of 100°C for 3 hours at a hydromodulus of 10.0. The resulting hydrolysate contains the following sugars (see Table 7).

The total sugar content in the hydrolysate is 4.4%, while (from the total concentration of sugars) the amount of xylose is 70%, arabinose - 18%, galactose - 9% and glucose - 2%.

The quality of the hydrolysate sent for subsequent 5-stage processing into xylitol is 84.5%.

PRIMER 4. 12

The beer dosage of type 1 is double-processed with ultrasound. The work was carried out on hydraulic module 10 for 15 minutes. (frequency 22 kHz, power 0.6Α). After this, the mass is separated in a screw press to obtain a solid phase and a liquid suspension. The phase ratio and cathode characteristics are presented in Table 4. (All indicators are given in absolute dry weight of the material).

Table 4

At the second stage of the process, high-temperature washing of the fibrous mass is carried out at a phase ratio (solid: liquid) of 1:6. Holding is carried out with periodic stirring for 10 minutes at 160°C. After that, the leading phase is separated from the suspension, the phase relationship and the chemical reactions are presented in the table. 4, and carry out hydrolysis of the solid phase with a 2% sulfuric acid solution at a temperature of 100°C for 3 hours at a hydromodulus of 10.

The obtained hydrolysate contains the following sugars (see Table 7). 13

The total sugar content in the hydrolysate is 4.9%, while (from the total concentration of sugars) the amount of xylose is 71.4%, arabinose - 16.3%, galactose - 10.2% and glucose - 2%. The quality of the hydrolysate sent for subsequent processing into xylitol is 86%.

POIΜΕΡ 5. Beer trough with 1 double-headed plasma in pulsation apapata PΑ-160 with a rotation speed of 3000 rpm. Micro grinding is carried out for 3 minutes with a hydromodule of 10. After this, the mass is separated on a screw press to obtain a solid phase of 40-50% moisture and a liquid suspension, the phase ratio and the characteristics of the catalyst are presented in Table. 5 (All indicators are given in absolute dry weight of the material).

Table 5

At the second stage of the process, high-temperature washing of the fibrous mass is carried out at a phase ratio (solid: liquid) - 14

1 : 8. Extraction is carried out by periodic stirring for 10 minutes at 160°C. After that, the leading phase is separated from the suspension, the phase relationship and the chemical reactions are presented in the table. 5, and carry out hydrolysis of the solid phase with a 2% sulfuric acid solution at a temperature of 100°C for 3 hours at a hydromodulus of 10.

The obtained hydrolysate contains the following sugars (see Table 7). The total sugar content in the hydrolysate is 4.5%, while (from the total concentration of sugars) the amount of xylose is 73.3%, arabinose - 14.5%, galactose - 10.0% and glucose - 2.2%. The quality of the hydrolysate sent for subsequent processing into xylitol is 87%.

Example 6. The beer bucket, in accordance with example 5, is processed in RPA-160 for 6 minutes. with hydromodule 10. After this, the mass is separated on a screw press to obtain a solid phase of 40-50% moisture and a liquid suspension; the phase ratio and catalyst characteristics are presented in Table. 6. (All indicators are given in absolute dry weight of the material).

Table 6.

15

15

At the second stage of the process, high-temperature washing of the fibrous mass is carried out at a phase ratio (solid: liquid) of 1:8. Holding is carried out with periodic stirring for 10 minutes at 160°C. After that, the leading phase is separated from the suspension, the phase relationship and the chemical reactions are presented in the table. 6, and carry out hydrolysis of the solid phase with a 2% solution of sulfuric acid at a temperature of 100°C for 3 hours at a hydromodulus of 10.

The obtained hydrolysate contains the following sugars (see Table 7).

The total sugar content in the hydrolysate is 4.8%, while (from the total concentration of sugars) the amount of xylose is 74.4%, arabinose - 12.78%, galactose - 10.6% and glucose - 2.2%.

The quality of the hydrolysate sent for subsequent processing into xylitol is 88%. 5 Table 7

16

16

Let's go. Thus, the use of the developed method ensures an increase in the quality of hydrolysates obtained from beer mash using this technology, which has a favorable effect on the process of their subsequent use for obtaining crystalline xylose and xylitol. The developed method allows to preserve pentosans from decomposition under the influence of mineral acid used in the process of improving plant raw materials, while the proportion of xylose from the total sugars of the hydrolysate increases from 57% (the original raw material is beer mash) up to 84 - 87%, the content of arabinose decreases twofold (from 30 to 13 - 17%). In addition, a protein paste is formed containing up to 40% of crude protein. This ensures the preservation of the nutritional value of the components of the brewery, and therefore the possibility of their useful utilization in the food industry, as well as in dairy farming.

Claims

17 ΦΟΡΜULΑ IZΟBΡΕΤΕΗIYA. 1. A method for processing plant raw materials to obtain pentose hydrolysates containing mainly xylose, including sulfuric acid hydrolysis of pentose-containing plant raw materials at elevated temperature, characterized by TEM, THAT as a vegetable raw material they use beer sludge of natural moisture, which at the first stage of the process is subjected to disintegration in excess water with subsequent separation of the solid phase from the liquid suspension, at the second stage of the process they carry out high temperature washing of the solid phase in the process, the latter is mixed with water at a phase ratio of (solid: liquid) 1: 5 - 8, maintained with periodic stirring for 10 - 30 minutes at a temperature of 130 - 160 ° with subsequent separation Wedge phase, which then undergoes biphasic hydrolysis of sepic acid. 2. Method π.1, AVAILABLE ΤΕΜ, a double depth of disintegration in excess water for 1 - 15 minutes at a temperature of 25-45 °C 3 Method πππ.1, 2, ΟΤΑΑΑΑΤΤΕΜ, ΤΤΟπποtwo-fold disintegration on a disk mill with frequent vibration vibration 10 - 50 Hz. 4. Method No. 1, 2, AVAILABLE ΤΕΜ, with a large depth of two disintegration on ultrasound installation with a wave frequency of 22 and 44 kHz. 5. Method πο ππ.1, 2, ΟΤpersonalized ΤΕΜ, a deep depth of ποtwo disintegration on pulsating actuator with a rotation speed of 3000 rpm. 6. Method πο π.1, which is characterized by hydrolysis of hydroxyphase at 0.5 - 2.5% in the seine. acids at a temperature of 100 - 120°C for 2-4 hours