Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L1/00—Compositions of cellulose, modified cellulose or cellulose derivatives
  • C08L1/02—Cellulose; Modified cellulose
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08H—DERIVATIVES OF NATURAL MACROMOLECULAR COMPOUNDS
  • C08H8/00—Macromolecular compounds derived from lignocellulosic materials
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H11/00—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H11/00—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only
  • D21H11/12—Pulp from non-woody plants or crops, e.g. cotton, flax, straw, bagasse
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H11/00—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only
  • D21H11/16—Pulp or paper, comprising cellulose or lignocellulose fibres of natural origin only modified by a particular after-treatment
  • D21H11/18—Highly hydrated, swollen or fibrillatable fibres

Definitions

• the present disclosure generally relates to products obtained by processing non wood cellulosic raw material.
• the disclosure relates particularly, though not exclusively, to processing of non-wood cellulose by partial hydrolysis and homogenization to provide a polysaccharide product.
• Cellulose is a substance of great industrial importance having numerous applications.
• Primary source of cellulose in industrial applications is wood-based cellulose pulp.
• wood-based raw-material there are several problems such as environmental issues relating to unsustainable use of land and soil and heavy energy consumption required to grow, harvest and process wood- based material. These issues have created a need to find, on one hand, alternative sources of cellulose for producing new cellulosic materials.
• the industry is constantly searching for more economical methods and raw materials to produce high quality polysaccharide products.
• native cellulose is always in a microfibrillar form, being part of wall structures of the plant cell.
• cellulose microfibrils are distributed randomly forming a flexible membrane layer together with other polysaccharides, such as pectin and hemicelluloses.
• an additional secondary wall structure is formed after the cell is fully- grown, especially in various wood species.
• the microfibrils are highly aligned mostly in the same direction and tightly bound to each other through hydrogen-bonding and covalent lignin bridges, forming a very rigid structure.
• Cellulose microfibrils located either in primary or secondary walls are structurally very similar. Both type of microfibrils consist of highly aligned cellulose macromolecule chains forming mechanically strong cellulose crystals with hydrogen bonded parallel polymer chains.
• microfibrils are generally considered to contain only few faults along their axis, although the degree of crystallinity varies between plant species being generally higher for microfibrils obtained from secondary walls. It is commonly understood that, depending on the plant species, 18, 24, or 36 cellulose chains form the smallest aligned structure, which is known as cellulose elementary fibril having diameter of a few nanometers and lengths up to tens of micrometers. Although the secondary cell walls, for example in wood, are rich of cellulose microfibrils, isolation of the structures without damaging the fibrils itself is very difficult. Also, the needed fibrillation process is complicated, expensive, and often a chemical pre-treatment is needed prior to fibrillation.
• Plant tissues made of primary cell walls form an alternative source for the separation of the microfibrils.
• These alternative raw material sources are also rich in other polysaccharides such as pectin and hemicelluloses.
• the other polysaccharides are not forming crystalline structures are can be separated as soluble polymers using an appropriate technique.
• the soluble polysaccharides are being used separate to microfibrils, for example as viscosifying or stabilizing agents. It is an aim to solve or alleviate at least some of the problems related to prior cellulosic materials and their production methods.
• an aim is to provide a polysaccharide product which has good rheological and/or binder properties and which can be obtained economically and in an environmentally sustainable manner from side streams.
• a polysaccharide product obtained from non-wood cellulosic raw material and comprising water soluble components and water insoluble components, wherein: a. from the water soluble components that are larger than 1 kD, at least 50% have a molecular weight of at least 40 kD; and b. the water insoluble components comprise cellulose microfibril aggregates having a number average size below 200 pm; and wherein the amount of the dry matter of all water soluble components is at least 20 wt-% of the total dry matter of the polysaccharide product, and wherein the water soluble components and the water insoluble components are obtained from the non wood cellulosic raw material.
• the water soluble components comprise hydrolysis products obtainable by partial hydrolysis of the non-wood cellulosic raw material by an aqueous alkali solution.
• the water insoluble components comprise non-soluble cellulosic residue obtained after partial hydrolysis of the non-wood cellulosic raw material by an aqueous alkali solution, and release of the water-soluble hydrolysis products.
• a process for treating raw material comprising non-wood cellulose comprising: a. impregnating the raw material with an aqueous alkali solution; b. carrying out partial hydrolysis to provide a partially hydrolyzed product comprising non-soluble cellulosic material and water-soluble hydrolysis products; and c. homogenizing the partially hydrolyzed product to provide a polysaccharide product.
• a process for treating raw material comprising non-wood cellulose, the process comprising: treating the raw material with hydrogen peroxide to partially hydrolyze the raw material; optionally adding aqueous alkali solution; and homogenizing the partially hydrolyzed product to provide a polysaccharide product.
• polysaccharide product is manufactured by using the process of the second aspect, or by using the above alternative aspect.
• the polysaccharide product is advantageous because it is compatible and suitable for controlling stability and/or rheology in the above applications.
• polysaccharide product in paper & board products; natural or synthetic non-wovens, molded fiber products; natural fiber composites; as such or together with synthetic resin in wood panel products including plywood, particle board, MDF, hardboard, laminated wood panels; pellets including food, feed, fuel, fertilizer pellets; food products; feed products.
• the polysaccharide product is advantageous because it is compatible and suitable for use as a binder and/or barrier agent in the above applications.
• thermoset composites thermoplastic composites
• elastomers including natural or synthetic rubber constructions and tire formulations
• insulation materials including polyurethane and polystyrene foams.
• the polysaccharide product is advantageous because it is compatible and suitable for use as a strengthening agent and/or filler in the above applications.
• the present polysaccharide product, the process and the uses are also advantageous in being able to effectively utilize side-streams of agriculture and/or food/feed industry.
• the polysaccharide product can be manufactured preferably without producing any further side streams, i.e. all dry matter of the raw material is preferably incorporated in the polysaccharide product.
• Fig. 1 schematically shows the process for manufacturing the polysaccharide product, and the steps for separating the sample fractions that are used to characterize the product.
• raw material can be partially hydrolyzed either by alkali or by hydrogen peroxide.
• Fig. 2 shows transmission electron micrographs from (A-B) the polysaccharide product, (C-D) the non-soluble cellulosic fraction of the polysaccharide product, and (E-F) the non-soluble cellulosic fraction of the polysaccharide product that has been post-treated with alkali. Scale bars: 5 pm (A, C, E), 0.5 pm (B, D, F).
• the polysaccharide product has a Brookfield viscosity of at least 300cP determined as aqueous 2wt-% dry matter content, 50 rpm, vane spindle V- 72.
• At least 50% have a molecular weight of at least 40kD determined by size exclusion chromatography, preferably by using Superdex 200 prep grade column (5cm x 93.5cm, GE Flealthcare), flow rate 5ml/min, carbohydrate standards.
• the amount expressed as % refers to a dry weight.
• the water soluble components are obtained by hydrolysis of >110kD components into smaller fragments having a molecular weight in the range 40-110kD.
• the water soluble components and the water insoluble components are obtained by partially hydrolyzing the non-wood cellulosic raw material, followed by homogenization.
• the water soluble components and water insoluble components are both directly obtained from the non-wood cellulosic raw material, i.e. they originate from the same material. More preferably no side- stream is removed from the polysaccharide product during the present process.
• the water soluble components comprise oligo- and polysaccharides with monosaccharide repeating units of D-galactose, L-arabinose, D-galacturonic acid and L-rhamnose. These structures are soluble in water and constitute a part of the water soluble components. As the skilled person understands, the exact amount of a certain monosaccharide units depends on the type of raw material used in the process. However, solubilized oligo- and polysaccharides are released as hydrolysis products during the partial hydrolysis of the present manufacturing process.
• the water-soluble components do not contain a significant amount of D-glucose and/or D-xylose, which indicates that the partial hydrolysis in the present process is primarily targeted to hydrolyzing cell wall components other than cellulose and xylan.
• the non-soluble components comprise cellulose microfibrils and/or microfibril bundles which are smaller than 200pm.
• the non-wood cellulosic raw material, or the polysaccharide product is bleached.
• a bleached polysaccharide product can thus be obtained by bleaching the non-wood cellulosic raw material before impregnation, during impregnation, before partial hydrolysis, during hydrolysis, before homogenization, during homogenization, after homogenization, or any combination thereof. Preferably bleaching is done after the partial hydrolysis.
• polysaccharide product is non-bleached.
• the polysaccharide product comprises at least 12.5 mol alkali for one kg of dry non-wood cellulosic raw material, and has a maximum Brookfield viscosity of 11000 cP determined for aqueous 8wt-% cellulosic dry matter content, 50 rpm, spindle RV-6.
• the polysaccharide product has a cellulose content of less than 50 wt-%.
• the partial hydrolysis is carried out by using alkali, preferably NaOH or KOH, more preferably NaOH.
• the size of the cellulose microfibril aggregates is below 200pm.
• the size can be determined by using vacuum filtering through various woven filter mesh sizes. An embodiment of the method is described in Example 14. At 1wt-% aqueous mixture preferably at least 95% of the dry matter of the polysaccharide product passes a screen having a mesh size of 167x167pm, i.e. also the non-soluble components have a size below 167pm.
• the non-soluble components are capable of passing through the screen of a sieve or a filter having a 175x175pm mesh size.
• the product obtained with the present process does not contain large (>200pm) components.
• the impregnation is carried out to a dry matter content of 10-35 wt-%, more preferably to 15-25 wt-%. These amounts are preferable to avoid bleeding while providing sufficient amount of alkali solution for the partial hydrolysis.
• the dry matter content of the partially hydrolyzed product is IQ- 35 wt-%, preferably to 15-25 wt-%.
• the amount of dry matter does not significantly change between the impregnation step and during the partial hydrolysis.
• no side stream is necessarily removed from the present process.
• the present process is advantageous in being able to process the raw material into an added value product.
• the raw material can be fully processed with the present process into a form of the polysaccharide product.
• the dry matter content of the homogenized product is 1-35 wt-%, preferably to 4-15 wt-%.
• the dry matter content of the homogenized product does not significantly change in the homogenization step.
• it is possible to add water before homogenization to carry out the homogenization step in a lower consistency. Dilution prior to homogenization is especially useful as it simultaneously mixes the dilution water into the final product and a separate post dilution step can be avoided.
• the impregnation is carried out to a dry matter content of 10-35 wt-%, more preferably 15-25 wt-%; the dry matter content of the partially hydrolyzed product is 10-35 wt-%, preferably 15-25 wt-%; and the dry matter content of the homogenized product is 1-35 wt-%, preferably 4-15 wt-%.
• the partial hydrolysis is carried out with an alkali, preferably NaOH, at a temperature selected from the range 60-100°C, preferably from the range 75-90°C.
• an alkali preferably NaOH
• the ratio of alkali to raw material expressed as an amount of moles of alkali per 1 kg of dry non-wood cellulosic raw material is at least 0.5 mol/kg, preferably the amount is selected from the range 1.25-4.5 mol/kg, more preferably from the range 1.5-4.5 mol/kg, and even more preferably from the range 1.5-1.75 mol/kg.
• the partial hydrolysis is carried out with hydrogen peroxide at a temperature selected from the range 60-100°C, preferably from the range 75-90°C.
• the ratio of hydrogen peroxide to raw material expressed as an amount of moles of hydrogen peroxide per 1 kg of dry non-wood cellulosic raw material is at least 0.1 mol/kg, preferably the amount is selected from the range 0.5- 4 mol/kg, more preferably from the range 1-3 mol/kg, and even more preferably from the range 1 .5-2.5 mol/kg.
• partial hydrolysis is carried out for at least 20min.
• the exact time for carrying our partial hydrolysis depends on the factors such as moisture content and the type of raw material, concentration of the alkali or hydrogen peroxide, and temperature.
• the skilled person is capable of determining an appropriate hydrolysis time e.g. by following the release of hydrolysis product by chemical analysis or the consumption of alkali or hydrogen peroxide by determining a change in the pH.
• the amount and concentration of the added aqueous alkali solution is selected such that it is essentially impregnated in the raw material.
• the homogenization is started when the proportion of the water soluble components to the water insoluble components is at least 20% of the total dry matter.
• the homogenization is carried out by using a rotor-rotor homogenizer and/or a high-shear mixer.
• the partially hydrolyzed product is transferred to an intermediate silo.
• the intermediate silo can be used to complete the partial hydrolysis before starting the homogenization step.
• the partially hydrolyzed product is bleached with hydrogen peroxide, chlorine, chlorine dioxide, ozone, or any combination of these.
• the partially hydrolyzed product is bleached with hydrogen peroxide utilizing a complexation chelating agent such as diethylenetriaminepentaacetate DTPA or similar.
• the chelating agent is preferably added prior to adding hydrogen peroxide.
• the raw material is treated with hydrogen peroxide to effect partial hydrolysis
• alkali is optionally added to the hydrogen peroxide treated raw material to neutralize the material, and then the process is continued in the homogenization step.
• alkali is added to achieve a pH above 6, such as a pH selected from the range 7-10 or preferably 7-9, before homogenizing.
• the hydrogen peroxide treatment has a similar and/or corresponding effect to the raw material as the combination of the impregnation step a. and the partial hydrolysis step b. This effect is demonstrated in Example 16 where viscosity, turbidity and sedimentation volumes were analyzed for the material obtained in partial hydrolysis by hydrogen peroxide, i.e. the hydrogen peroxide treatment.
• the hydrogen peroxide treatment is carried out by an aqueous hydrogen peroxide reagent solution.
• the reagent solution may optionally contain formic acid or another acid.
• the initial pH is set to a value within the range from 3-5 by an acid.
• the acid is an organic acid, such as formic acid.
• the acid is a mineral acid.
• the hydrogen peroxide treatment is carried out at a temperature selected from the range 70-99°C, preferably 80-95°, more preferably at about 90°C.
• the raw material to which the hydrogen peroxide treatment is used is or comprises cassava pulp and/or sugar beet pulp.
• the progress of the hydrogen peroxide treatment is monitored by following the decrease of the pH during the hydrolysis.
• the hydrolysis can thus be stopped when a desired pH level is reached.
• the peroxide treatment may be stopped when the pH has decreased at least about 1 pH unit, about 1 .5 pH units, about 2 units, about 2.5 pH units, or about 3 pH units, or more.
• the partial hydrolysis product is finished when the pH does not change any more.
• a catalyst such as FeS0 4 , is added to the hydrogen peroxide treatment.
• the pH is set to a valued within range 9-10.
• the partially hydrolyzed product is further treated with an additional amount of alkali during or after homogenization, or any combination of these.
• Additional alkali hydrolysis may be advantageous to provide a product in which the amount of water-soluble hydrolysis products is further increased to change rheological properties of the product.
• the product with additional alkali treatment is also advantageous when using the obtained product with phenolic resins that are alkalic.
• the amount of the additional amount of alkali is selected such that the water soluble components comprise at least 50 wt-% of the total dry matter of the polysaccharide product after the additional alkali treatment is complete.
• the process conditions, such as temperature, of the additional alkali treatment can be the same as used in the partial hydrolysis.
• the product obtained with additional alkali treatment has lower viscosity compared to non-treated product, which enables easier handling with e.g. pumps in a higher consistency, e.g. at 8-10 wt-%.
• Non-wood cellulosic raw material in the present disclosure means cellulosic, i.e. cellulose containing, material obtainable from non-wood material.
• non wood cellulosic raw material include e.g. parenchymal cellulose, cellulose from fruits, vegetables, legumes, cereals, seeds, grains, roots, tubers, sugar beet pulp, potato pulp, cassava pulp, citrus peel, bagasse pith, sweet potato, corn, rice, wheat, soy, and mixtures thereof.
• Especially well suitable non-wood cellulosic raw materials are sugar beet pulp, bagasse pith fraction, potato pulp, cassava pulp and mixtures thereof.
• non-wood cellulosic raw material is selected from sugar beet pulp, dry sugar beet pulp, wet sugar beet pulp, sugar beet pellet or any combination thereof.
• non-wood cellulosic material is selected from potato pulp, cassava, bagasse, soya and any combination thereof.
• Non-wood cellulose microfibrils refer, in the context of this disclosure, to non-wood cellulose microfibrils or non-wood cellulose microfibril bundles or non-wood cellulose microfibril aggregates that are at least partially separated from cell walls from suitable non-wood cellulosic non-wood raw material(s).
• the aspect ratio of the homogenized microfibrils is typically very high; the length of the microfibrils may be more than one micrometer and the number-average diameter is typically less than 200 nm, such as between 2 and 100 nm.
• the diameter of microfibril bundles may be greater, but it is usually less than 1 pm.
• microfibrils are similar to the so-called elementary fibrils, the diameter of which is typically 2 to 12 nm.
• these isolated microfibrils for example: nanocellulose, microfibrillar cellulose, nanofibrillated cellulose, cellulose nanofiber, nanoscale fibrillated cellulose, m icrof i b ri 11 ated cellulose (MFC), homogenized non wood cellulose, cellulose microfibrils, or fibrillated non-wood cellulose.
• MFC m icrof i b ri 11 ated cellulose
• Non-wood cellulose microfibrils that have been separated from the primary cell wall may contain other polysaccharides, such as pectin, hemicellulose, and/or other soluble polysaccharides.
• the amount of the other polysaccharides depends on the non-wood cellulosic raw material used and on the separation method.
• the cellulose microfibrils separated from the primary cell walls may be in a form of expanded fibrillar network, where individual microfibrils or microfibril bundles are still partially bound or entangled to each other, even after they have been subjected to homogenization.
• Such partially bound or entangled individual microfibrils and/or microfibril bundles may be referred to as non-wood cellulose microfibril aggregates.
• the size or diameter of these aggregates is typically 10 to 500 micrometers when diluted into water. The size is, however, dependent on the concentration and the degree of homogenization and can be below 200 micrometers when measured by a filtration test.
• Homogenizing in the present disclosure means mechanically treating the partially hydrolyzed material to be a continuous gel when in water, even at low concentration such as at 2 wt-% used in the viscosity measurements of the Examples.
• a continuous gel in this context means a mixture of the homogenized product and water, which does not settle out of the continuous phase at rest.
• the present polysaccharide product After homogenization the present polysaccharide product has improved rheological properties and the resulting gel has increased viscosity.
• Homogenizing can be carried out by using a grinder, comminutor, rotor-rotor- homogenizer, rotor-stator mixer or a grinder such as Ultra-Turrax, Masuko from Masuko Sangyo, rotor-rotor mixer or a grinder such as Atrex-type devices, a homogenizer such as Ariete-type or Panda-type from GEA Niro-Soavi, fluidizer, micro- or macrofluidizer such as microflu id izer from Microfluidics and/or ultrasonic disintegrator.
• a grinder comminutor, rotor-rotor- homogenizer, rotor-stator mixer or a grinder such as Ultra-Turrax, Masuko from Masuko Sangyo, rotor-rotor mixer or a grinder such as Atrex-type devices
• a homogenizer such as Ariete-type or Panda-type from GEA Niro-Soavi
• fluidizer micro- or
• the non-wood cellulosic raw material is pre-treated by mechanical milling before the impregnation step.
• Mechanical milling can be carried out for example by a roller mill.
• Pre-treatment by milling is advantageous when using raw material with a larger size, such as pellets, but it is not mandatory.
• By the pre treatment by milling hydration is enhanced, thereby enhancing the impregnation step.
• the amount of the dry matter of the water soluble components is not more than 50 wt-% of the total dry matter of the polysaccharide product.
• a portion of the water soluble components is removed from the polysaccharide product.
• the water soluble components can be removed e.g. by slightly pressing the polysaccharide product to release water soluble components absorbed inside the water soluble components.
• the dry matter content of the homogenized product is 1-35 wt -%, preferably 4-15 wt-%.
• additional compounds are added into the polysaccharide product before after or during the homogenization, such as synthetic or natural biocides, mineral or organic acids, water soluble polymers, water insoluble polymers, glycerol, glycol, any type of salt, fragrances, coloring agents, solid carriers, natural fibers, synthetic fibers, feed ingredients, lignin, or any combination thereof.
• partial hydrolysis and partially hydrolyzed product means that when the raw material is treated with an alkali, or with hydrogen peroxide, partial, but not complete, hydrolysis of the raw material is achieved. Some of the hydrolysis products remain non-soluble, and some can be washed by water to be analyzed as water-soluble hydrolysis products.
• partial hydrolysis and (partial) hydrolysis products are considered in a broader context to include depolymerization and/or oxidation/cleaving of molecular bonds.
• the resulting product contains the components released during partial hydrolysis, and the non-soluble cellulosic material.
• the present process is advantageous compared to previous processes that involve use of larger amount of alkali solution and removal of liquid phase(s) during alkali treatment. With the present process no side streams that are difficult and costly to process further, are produced.
• the composition of the water-soluble hydrolysis products obtained with the present process differs from those obtained using prior processes, such as those where a water-soluble fraction has been washed or removed from hydrolyzed cellulosic material or that have carried out partial hydrolysis at different conditions or with a different amount of alkali.
• the amount and concentration of the aqueous alkali solution is selected such that it is essentially impregnated in the raw material.
• the amount and concentration of the aqueous alkali solution is selected such that it is essentially impregnated in the raw material.
• bleeding can be avoided. If too much alkali solution is used, the raw material cannot withhold all liquid and excess liquid forms a liquid phase which separates from the raw material, which is called bleeding.
• Homogenizing can be started when the amount of water-soluble hydrolysis products has reached the claimed level or by following e.g. a change in the pH as described above. When this amount of hydrolysis products is reached, essentially all alkali is consumed and the end of partial hydrolysis is reached and there is no need to stop the hydrolysis in any way.
• the impregnation is carried out in an optionally inclined tubular reactor equipped with a single screw conveyor or twin screw conveyor .
• the partially hydrolyzed product is transferred to an intermediate reservoir, or a silo.
• the intermediate reservoir e.g. residence time in a previous step involving addition and impregnation of alkali into the raw material can be shortened and the partial hydrolysis of the raw material with the alkali impregnated into it can be allowed to proceed to a desired stage before starting the homogenization step.
• Dry matter content in the content of this disclosure refers to the fraction of mass remaining after the removal of volatile components at 105 °C.
• Water soluble in the context of this disclosure refers to components present in the liquid fraction of a sample that is fractionated using a common solid-liquid separation technique, such as centrifugation at a relative centrifugal force of 5250 g for 20 minutes, or pressure filtration through a 40-pm membrane.
• Washed product in the context of this disclosure refers to product that has been washed with water so that water-soluble components have essentially been removed.
• Non-extractables in the context of this disclosure refers to the fraction of non-soluble dry matter that remains non-soluble after post-treating washed product with an excess amount of alkali as follows.
• the washed product is dispersed to an amount of 0.8 M alkali solution corresponding to 25 mol/kg (mol of alkali per kg of washed product dry matter).
• the mixture is reacted for 4 hours at 80°C.
• the reacted mixture is centrifuged (5250 g, 20 minutes), and the separated liquid is carefully discarded without disturbing the sediment.
• the sediment is then washed at least three times by redispersing the sediment in distilled water to a volume equal to or larger than the original volume of the alkali dispersion, centrifuging the mixture (5250 g, 20 min), and carefully discarding the separated liquid without disturbing the sediment. Finally, the sediment is dried and weighed, and the fraction of non-extractables is calculated as the dry mass of sediment/ initial dry mass of washed product.
• the term comprising includes the broader meanings of including, containing, and comprehending, as well as the narrower expressions consisting of and consisting only of.
• soluble refers to water soluble.
• non-soluble refers to water-insoluble.
• process steps are carried out in the sequence identified in any aspect, embodiment or claim.
• any process step specified to be carried out to a product or intermediate obtained in a preceding process step is carried out directly to said product, i.e. without additional, optional or auxiliary processing steps that may chemically or physically alter the product between said two steps.
• Dry sugar beet pulp shreds and NaOH water solution were fed into a continuous reactor heated to 80°C.
• the residence time in the reactor was 45 minutes, and NaOH dosing was 1.5, 3.0, or 4.5 mol NaOH/kg of beet pulp dry matter.
• the reactor design was an inclined twin screw conveyor with a steam jacket. Partially hydrolyzed product, having a dry matter content of 17%, was collected at reactor output.
• the product samples were characterized as follows. 275 ml of 0.1 M NH4HCO3 was added on 25 g of product, and the mixture was stirred gently for 5 h. Thereafter, the sample mixtures were centrifuged (3220 g, 30 min) to separate the soluble and non soluble fractions.
• the dry matter fractions of the soluble and non-soluble fractions were quantified.
• the soluble fraction was then filtrated using a pressure-driven ultrafiltration device (Amicon stirred cell Model 8400, Merck-Millipore) using regenerated cellulose membrane with a molecular weight cut-off 1000 Da.
• the fraction of dissolved molecules larger than 1 kD was quantified. Results are shown in Table 4. The data shows that the fraction of dissolved > 1 kD molecules increases with increasing NaOH dosing.
• Example 5 The dissolved > 1 kD fraction from Example 4 was further purified with Solid Phase Extraction, Bond Elut C18 cartridges (Agilent technologies). The purified samples were fractionated according to size by size exclusion chromatography using column of Superdex 200 prep grade (5 cm x 93.5 cm; resin, GE Healthcare). The flow rate was 5 ml/min. According to carbohydrate standards, five fractions separated by molecular weight were collected. The pooled fractions were dried, and their dry weights were measured. The proportional yield is shown in Table 5. The results show that the >110 kDa fraction is hydrolyzed to smaller polysaccharides with a molecular weight between 40 and 110 kD as the amount of alkali is increased. However, the amount of molecules smaller than 40 kDa does not increase.
• the dissolved > 1kD fraction from Example 4 was further characterized by hydrolyzing the sample to monosaccharides in 2 M TFA at 120°C, which were labelled with two-step reaction, first cysteine methyl ester in pyridine followed by addition of o-tolyl isothiocyanate at 60°C.
• the derivatized monosaccharides were analyzed by reversed phase HPLC using Gemini-NX C18 (Phenomenex), absorbance at 250 nm was monitored. The relative proportions of monosaccharides are shown in Table 6. In the HPLC measurement above, galacturonic acid and xylose signals are overlapping. To resolve this pair of monosaccharides, the samples were subjected to NMR spectroscopy.
• Crushed sugar beet pellets (dry matter content 88%) were mixed with a heated water solution of NaOH or KOH to obtain an alkali to dry raw material feed of 1.5 mol/kg (dry) and a sugar beet dry matter content of 21%. The mixture was allowed to react at 80 °C for 40 minutes to obtain partially hydrolyzed product.
• Crushed sugar beet pellets (dry matter content 88%) were mixed with a heated water solution of NaOH and chelating agent (Diethylenetriaminepentaacetate DTPA) to obtain a NaOH to dry raw material feed of 1 .5 mol/kg (dry) and DTPA to dry raw material feed of 4 g/kg (dry) and a sugar beet dry matter content of 21%.
• the mixture was allowed to react at 80 °C for 40 minutes, after which a heated water solution of hydrogen peroxide was added, to obtain a H2O2 to dry raw material feed of 45 g/kg (dry) and a sugar beet dry matter content of 15%.
• the mixture was allowed to react at 80 °C for 30 minutes to obtain bleached partially hydrolyzed product.
• Examples 8 and 9 Materials obtained from examples 8 and 9 were homogenized by passing them four times through a high-pressure homogenizer at 400 Bar (GEA Niro Soavi, PandaPlus 1000) or by high-shear mixing at 12.5 krpm for 180 seconds. The materials were diluted with water to 2.0 wt-% prior to the mechanical treatment. The viscosities of the resulting homogenized products are presented in Table 7.
• Example 12 Alkali post-treatment of homogenized partially hydrolyzed product To Sample 3E from Example 3, NaOH (50% solution) or water was added to obtain the compositions presented in Table 9. Brookfield viscosities were measured from the obtained mixtures and compared to reference mixtures where an equivalent volume of water was added instead of NaOH. The RV-6 spindle was used. A significant reduction in viscosity could be observed.
• the product was fractionated by pressure filtration through a 40 pm filter, yielding a liquid fraction with a dry matter content of 13.7%.
• 63.5% of total dry matter was water-soluble.
• the liquid was further characterized by viscometry. The results are presented in Table 10.
• Table 10 Brookfield viscosity of the liquid fraction at different shear rates, measured using a vane spindle (model V-72).
• Example 14 The filterability of partially hydrolyzed, homogenized sugar beet product was evaluated from samples diluted to 1.00 wt-%. A sample of 200 g was vacuum filtrated through various woven filter mesh sizes. A maximum filtration time of 2 minutes was used. The dry matter content was measured from the filtrate to determine the amount of passed material. The results are shown in Table 11 .
• Example 15 For transmission electron microscopy (TEM), Sample 3E was diluted with distilled water so that the concentration of the non-dissolving fraction was 0.1 %. To observe the non-soluble cellulosic fraction without the presence of the soluble components, samples REF and NaOFI-B from Example 12 were diluted with distilled water so that the concentration of the non-dissolving fraction was 0.1 %, and washed by centrifugation (5250 g for 20 minutes, 3 times centrifugation/dilution to the initial volume). The suspensions were placed to an ultrathin carbon film TEM grid. The excess liquid was blotted away with filter paper. The samples were imaged with FEI Tecnai 12 TEM at 120 kV acceleration voltage.
• TEM transmission electron microscopy
• the TEM images are shown in Fig.2.
• A-B the polysaccharide product
• C-D the non-soluble cellulosic fraction of the polysaccharide product
• E-F the non-soluble cellulosic fraction of the polysaccharide product that has been post-treated with alkali.
• the images show that the product comprises loose bundles or networks of cellulose microfibrils.
• the microfibrils typically have a diameter between 20 and 200 nm. It is noted that some of the fibril aggregates that are seen in the images may be formed by capillary forces during sample preparation. It can be seen by comparing panels 2D and 2F that the fibril structure of the product is not visibly affected by the additional alkali treatment that was used for reducing the viscosity of the sample in Example 12.
• Cassava pulp (powder form, dry matter content 87.8%, starch content approximately 50% of dry matter) was partially hydrolyzed with hydrogen peroxide solution as follows: Flydrogen peroxide (35 wt-%) 26. Og was dissolved in 489.4 g of water pre heated to 90 °C. 150.0 g of cassava pulp was mixed with the peroxide solution and the mixture was transferred into a polypropylene bottle. The reaction was continued in oven at 90 °C for 60 minutes and thereafter cooled to room temperature using a water bath. The pH of the mixture dropped from around 5.5 to 3.5 during reaction.
• the total dry matter content of the reacted mixture was determined to be 20.4% (determined by oven drying at 109 °C for 24 hours), having a solubilized fraction of 15.0% (or 73.5% of total dry matter, determined by pressure filtration and oven drying at 109 °C for 24 hours).
• the sample viscosity and tackiness resulting from high starch content of cassava pulp was reduced, likely due to dextrinization by hydrogen peroxide, making processing of the material easier.
• Sugar beet pulp crushed pellets, dry matter content 88.9% was partially hydrolyzed with hydrogen peroxide solution as follows: Hydrogen peroxide (35 wt-%) 26. Og and formic acid (85 wt-%) 2.4 g were dissolved in 325.5 g of water pre-heated to 90 °C. 100.3 g of sugar beet pulp was mixed with the reagent solution and the mixture was transferred in a polypropylene bottle. The reaction was continued in oven at 90 °C for 90 minutes and thereafter cooled to room temperature using a water bath. The pH of the mixture was 3.2 after reaction.
• the total dry matter content of the reacted mixture was determined to be 20.2% (determined by oven drying at 109 °C for 24 hours), having a solubilized fraction of 12.6% (or 62.4% of total dry matter, determined by pressure filtration and oven drying as above).
• the viscosity of the homogenized samples were measured by Brookfield DV3T viscometer (RV-torque range, Brookfield Engineering Laboratories, Middleboro, USA) equipped with a vane geometry (V-72, diameter 21.67 mm, length 43.38 mm). The samples were measured at 2 wt-% and 50 and 100 rpm shear rates. The temperature was adjusted to 20 °C prior to measurements.
• Turbidity of dilute aqueous dispersions of homogenized parenchymal cellulose was measured with HACH P2100 turbidimeter.
• the product was diluted with water to a concentration of 0.2 wt%, and the sample was agitated for 10 min before the measurement followed by degassing in vacuum to remove the entrapped air bubbles in the sample.
• the sedimentation volume was determined for 0.2 wt-% cellulose content in transparent 15 ml Falcon test tubes. A total of 13.0 ml sample volume was used and allowed to stand at room temperature for 24 hours to obtain the sedimentation volume i.e. the volume occupied by the sediment material.
• the example shows that hydrogen peroxide can be utilized for producing fibrillated parenchymal cellulose from cassava and sugar beet pulp.
• the tackiness of of peroxide treated pulps and corresponding fibrillated products is also significantly reduced, making the processing of the material easier.
• the resulting products are light in color and stable against microbial growth due to sterilizing conditions.
• the hydrogen peroxide treatment can be enhanced with addition of catalysts, such as FeS0 4 , if not naturally present in the raw material in sufficient amounts to promote Fenton and Fenton-like reactions.
• Formic acid can be used for pH adjustment, and for forming performic acid in situ.
• the water insoluble components comprise cellulose microfibril aggregates having a number average size below 200pm; and wherein the amount of the dry matter of all water soluble components is at least 20wt-% of the total dry matter of the polysaccharide product, and wherein the water soluble components and the water insoluble components are obtained from the non-wood cellulosic raw material.
• the polysaccharide product of clause 1 wherein the polysaccharide product has a Brookfield viscosity of at least 300cP determined as aqueous 2wt-% dry matter content, 50rpm, vane spindle V-72.
• a process for producing the polysaccharide product of clauses 1 -7 by treating raw material comprising non-wood cellulose comprising: a. impregnating the raw material with an aqueous alkali solution; b. carrying out partial hydrolysis to provide a partially hydrolyzed product comprising non-soluble cellulosic material and water-soluble hydrolysis products; and c. homogenizing the partially hydrolyzed product to provide a polysaccharide product.

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