Steam Explosion Treatment Research Articles

Changes in Permeability and Sound Absorption Capability of Yellow Poplar Wood by Steam Explosion Treatment

Wood is widely used as a housing material because of its environmental superiority, good mechanical properties, fine appearance, and high thermal insulation properties. However, wood is a sound reflecting material with a relatively low sound absorption capability. It is recognized that the sound absorption capability of wood is influenced by air permeability that varies by the sound incident surface structure. Wood is a porous material which has numerous cylindrical pores in the fiber direction. However, the permeability of wood is relatively low because there are very few continuous pores in wood. The pores in wood are classified into three types: through, blind, and closed. Among these pores, only the through pore has continuous vessel elements that readily permit fluid flow. Furthermore, the formation of pit–aspirations in softwoods or tylosis in hardwoods restricts the air or liquid flow in wood. Improving the permeability of wood has been an interest of many wood researchers because highly permeable solid wood can be treated easily by a functional treatment that allows the good dimensional stability, fire proofing, and other traits. It is generally recognized that wood treatability increases with permeability. Several treatments, such as steaming, extraction with solvents, and degradation with enzymes or microorganisms, have been attempted to increase the permeability of wood. However these treatments did not have a sufficient effect on increasing permeability, and a useful method has not yet been developed. In a previous paper, Kang et al. (2008 a) reported that the delignification treatment by Wise’s method improved wood permeability in the fiber direction, and that the sound absorption capability on the cross sectional surface of Larix kaemferi increased, as compared with the control wood. Also, it was found that the sound absorption capability of a mushroom bed log of Mongolian oak degraded by fungus over four years was 2–3 times higher than that of control wood (Kang et al., 2008 b). On the other hand, steam explosion is used in the field of pulp and fiberboard manufacturing or the wood– based biomass industry and is exposure to violent pressure and temperature changes via steam. For this treatment, the target material is mounted in a closed chamber, and then superheated steam is introduced from a boiler. The superheated steam heats the chamber and target material to a high temperature and pressure, which is maintained for a moment and then discharged abruptly by a blasting device. By this process, high–pressure Changes in Permeability and Sound Absorption Capability of Yellow Poplar Wood by Steam Explosion Treatment

Modification of Wheat Straws through Steam Explosion and its Effect on Panel Properties

Particleboards bonded with urea formaldehyde (UF) and a combination of UF and methylene diphenyl diisocyanate (MDI) resins were manufactured using wheat straws modified through different steam explosion treatments. The effect of steam explosion treatment, resin system, and mixing ratios of wood and straw materials on the panel properties was investigated. Generally, with steam explosion treatment of straw fibers, panel properties in bending and internal bond (IB) strength increased, thickness swelling (TS) and water absorption (WA) decreased. The bending properties for the panels made from the straws pretreated with 12 h water-soaking were significantly improved at the UF/MDI content level of 5%/1%. The IB strength dramatically increased, while TS and WA decreased with the use of dual resins. With increased weight ratio of wheat straw to wood particles, the bending properties, IB strength, TS and WA deteriorated. Pure wheat straw boards had the lowest properties. Wood particles in substitution for part of straw materials helped improve the panel properties. The results demonstrated that steam explosion modification and/or its combination with UF/MDI dual resin system can be a feasible approach to improve the bonding strength for wheat straw based particleboards.

Structure, morphology and thermal characteristics of banana nano fibers obtained by steam explosion

In this work, cellulose nanofibers were extracted from banana fibers via a steam explosion technique. The chemical composition, morphology and thermal properties of the nanofibers were characterized to investigate their suitability for use in bio-based composite material applications. Chemical characterization of the banana fibers confirmed that the cellulose content was increased from 64% to 95% due to the application of alkali and acid treatments. Assessment of fiber chemical composition before and after chemical treatment showed evidence for the removal of non-cellulosic constituents such as hemicelluloses and lignin that occurred during steam explosion, bleaching and acid treatments. Surface morphological studies using SEM and AFM revealed that there was a reduction in fiber diameter during steam explosion followed by acid treatments. Percentage yield and aspect ratio of the nanofiber obtained by this technique is found to be very high in comparison with other conventional methods. TGA and DSC results showed that the developed nanofibers exhibit enhanced thermal properties over the untreated fibers.

Bioconversion of hemicellulose hydrolysate of sweet sorghum bagasse to ethanol by using Pichia stipitis NCIM 3497 and Debaryomyces hansenii sp.

Production of ethanol from concentrated D-xylose solutions and hemicellulose hydrolysate of sweet sorghum bagasse was achieved by using Pichia stipitis NCIM 3497 and an isolated yeast Debaryomyces hansenii sp. These yeasts werecapable of producing ethanol from solutions containing 800 g/L D-xylose, and the optimum sugar concentration was found to be 150 g/L at pH 4, 30oC, with a production time of 72 hours. These yeasts were capable of utilizing multiple sugars. Hemicellulose hydrolysates of sweet sorghum bagasse were obtained by dilute acid hydrolysis and autohydrolysis including steam explosion treatment. The hydrolysate was treated by an over-liming process for detoxification and pH adjustment. Ethanol yield from hemicellulose hydrolysate was found to be higher than that of synthetic medium containing D-xylose. These yeasts can be used in production of ethanol from concentrated hemicellulose hydrolysates containing high pentose sugars obtained while treating lignocellulosic biomass at high substrate concentrations.

Effect of steam explosion treatment on characteristics of wheat straw

Steam explosion treatments were used to modify straw fiber attributes for panel manufacturing. In particular, the effect of steam temperature and retention time on morphology, acidity, wettability, and ash and silicon contents of wheat straw was studied. After steam explosion treatments, proportion of large particles decreased, while fiber bundles increased. Higher steam temperature and longer retention time resulted in more homogeneous fiber-like material. The results showed that the pH value of the untreated wheat straw fiber was nearly 7 and the pH values and acid buffer capacities of straw were greatly reduced after steam explosion treatments. This indicated that the acidity of straw increased after steam explosion treatments. The dynamic contact angle of the straw before the treatment was nearly 90°, indicating that the straw material without treatment is more hydrophobic. After steam explosion treatments, the contact angle of straw was significantly reduced, showing that the surface wettability of the treated straw was improved. The ash and silicon contents of straw were also significantly reduced by steam explosion treatments. The improved acidity and wettabillity as well as decreased silicon content would contribute to the improved bondability between straw particles and water-soluble adhesive binders.

Thermo characteristics of steam-exploded bamboo (Phyllostachys pubescens) lignin

Bamboo (Phyllostachys pubescens) internode was subjected to steam explosion treatment to produce an excellent fiber for binderless boards. Lignin was isolated from extract-free bamboo meal with Bjorkman’s procedure and steam-exploded pulp. The self binding-mechanism was discussed by scanning electron microscopy (SEM), thermo-gravimetry (TG), differential scanning calorimetry (DSC) and analytical ozonation. It is well-known that steam explosion treatment liberates lignin from the cell wall to the fiber surface, which is the most important component relevant to binderless board production. Results of TG and DSC analyses showed that steam-exploded bamboo pulp started mass loss at lower temperature compared to bamboo internode meal. The thermal softening temperature of lignin prepared from steam-exploded pulp was much lower than that of lignin prepared from extract-free bamboo meal. This suggests that intermonomer linkages of lignin, especially β-aryl-ether linkage which is the major intermonomer linkage of lignin, were cleaved during steam explosion treatment resulting in low molecular weight phenolic compounds. The cleavage of β-aryl-ether intermonomer linkage of lignin was also confirmed by ozonation analysis.

Studies of the effect of molding pressure and incorporation of sugarcane bagasse fibers on the structure and properties of poly (hydroxy butyrate)

Poly (hydroxy butyrate) (PHB) is a biodegradable polymer that can be obtained from both renewable and synthetic resources. There have been many attempts to improve its structure and properties by different methods. This paper, while mentioning briefly PHB and sugarcane bagasse fibers, focuses on the effect of compressive/molding pressure on its structure and thermal properties with incorporation of sugarcane bagasse fibers, with and without steam explosion treatment. Thermal behavior (thermogravimetry and dynamic mechanical analysis), X-ray diffraction, Fourier transform infrared spectroscopy, optical microscopy methods were used to understand the changes in PHB resulting from the pressure and incorporation of fibers while scanning electron microscopy is used to understand the morphology of both the fiber and PHB.

Study on tensile properties and Interfacial Shear Strength of bamboo fibre bundles

The tensile properties and Interfacial Shear Strength (IFSS) of bamboo fibre bundles were studied. Bamboo fibres were extracted by three different methods: steam explosion, mercerisation and chemical treatment. The diameter, tensile strength and modulus of the extracted-bamboo fibre bundles were decreased by all the processes compared to untreated bamboo fibres. But the tensile properties of mercerised bamboo fibre bundles were better than those of other treatments with the exception of untreated bamboo fibres. The interfacial shear stress distribution of chemically treated fibres was higher than that of steam explosion and mercerised bamboo fibres.

Effect of inhibitors released during steam-explosion treatment of poplar wood on subsequent enzymatic hydrolysis and SSF.

Steam-exploded (SE) poplar wood biomass was hydrolyzed by means of a blend of Celluclast and Novozym cellulase complexes in the presence of the inhibiting compounds produced during the preceding steam-explosion pretreatment process. The SE temperature and time conditions were 214 degrees C and 6 min, resulting in a log R(0) of 4.13. In enzymatic hydrolysis tests at 45 degrees C, the biomass loading in the bioreactor was 100 g(DW)/L (dry weight) and the enzyme-to-biomass ratio 0.06 g/g(DW). The enzyme activities for endo-glucanase, exo-glucanase, and beta-glucosidase were 5.76, 0.55, and 5.98 U/mg, respectively. The inhibiting effects of components released during SE (formic, acetic, and levulinic acids, furfural, 5-hydroxymethyl furfural (5-HMF), syringaldehyde, 4-hydroxy benzaldehyde, and vanillin) were studied at different concentrations in hydrolysis runs performed with rinsed SE biomass as model substrate. Acetic acid (2 g/L), furfural, 5-HMF, syringaldehyde, 4-hydroxybenzaldehyde, and vanillin (0.5 g/L) did not significantly effect the enzyme activity, whereas formic acid (11.5 g/L) inactivated the enzymes and levulinic acid (29.0 g/L) partially affected the cellulase. Synergism and cumulative concentration effects of these compounds were not detected. SSF experiments show that untreated SE biomass during the enzymatic attack gives rise to a nonfermentable hydrolysate, which becomes fermentable when rinsed SE biomass is used. The presence of acetic acid, vanillin, and 5-HMF (0.5 g/L) in SSF of 100 g(DW) /L biomass gave rise to ethanol yields of 84.0%, 73.5%, and 91.0% respectively, with respective lag phases of 42, 39, and 58 h.

Changes in chemical characteristics of bamboo (Phyllostachys pubescens) components during steam explosion

Chemical changes in cell wall components of bamboo internode during steam explosion process were analyzed to investigate self-binding mechanism of binderless board from steam-exploded pulp. More than 30% of xylose on initial mass, which is a major hydrolyzate of bamboo hemicelluloses, was lost after steam explosion treatment. Bamboo lignin is characterized by the presence of ester- and/or ether-linked p-coumaric acid to lignin. The content of phenolic hydroxyl groups of lignin isolated from steam-exploded pulp was characterized 2.3 times higher than those of the extract-free bamboo internode due to the cleavage of β-O-4 linkages. Alkaline nitrobenzene oxidation of the bamboo lignin gave vanillin, syringaldehyde and p-hydroxybenzaldehyde as major products. The content of p-hydroxybenzaldehyde decreased after steam explosion treatment, indicating the cleavage of ester- and/or ether-linked p-coumaric acid. The total yield of erythronic and threonic acids in ozonation products of the extract-free bamboo internode lignin was 268 mmol (200 g lignin)−1, while those of lignins in the steam-exploded pulp and powdery fraction were 96 and 129 mmol (200 g lignin)−1, respectively, suggesting the significant cleavage of β-O-4 linkages during steam explosion treatment. The cleavage of β-O-4 linkages was also confirmed by 1H- and 13C-NMR spectroscopic observations.

Novel extraction method of antioxidant compounds from Sasa palmata (Bean) Nakai using steam explosion

Antioxidant compounds were extracted from various parts of Sasa palmata (Bean) Nakai, a bamboo plant whose leaves are commonly used to wrap foodstuffs such as Sushi in Japan. Highest concentrations of antioxidant compounds existed in the leaf part of S. palmata. Steam explosion treatment followed by hot water and methanol extractions was used for separating the antioxidant compounds from S. palmata leaf . The steam explosion treatment is the physical–chemical treatment which crushes a sample by sudden reduction of the pressure in reactor to atmospheric pressure after steaming the sample at high temperature and pressures. Sasa palmata leaf was hydrolyzed by steaming and crushed by the rapid decompression. The optimal condition of steam explosion for the effective extraction of antioxidant compounds from S. palmata was determined as a steam of temperature of 250 °C and a steaming time of 1 min. In these conditions 217.41 mg/(g- Sasa leaf) of phenolic compounds and 142.81 mg/(g- Sasa leaf) of radical scavenging activity, that was expressed as butylated hydroxyanisole (BHA), were obtained.

Acid impregnation and steam explosion of corn stover in batch processes

The synergistic effect of pre-impregnation by sulphuric acid and steam explosion has been investigated. Sugar recovery by water extraction and cellulose digestibility by enzymes have been considered. The acid diffusion inside a representative particle, having thickness of 0.7 mm, has been modelled on the basis of available models and diffusion coefficients. The experiments of acid impregnation have pointed out a plateau of the acid uptake after 10 min corresponding to an acid adsorption of 22 g/kg of dry stover. An experiment of acid desorption from the pre-impregnated biomass particles to a new bulk of pure water (reverse diffusion), has confirmed that only a small fraction of the uptaken acid remained free, while most has been consumed by the substrate. Nine conditions have been tested for the steam explosion treatment selecting the temperature of 180, 190, 200 °C and sulphuric acid loadings of 0, 1.5, 3 wt.%. The maximum sugar recovery by water extraction is produced by a SE treatment of 190 °C for 5 min and an acid loading of 1.5 wt.%; at these conditions 25% of the sugars in the feedstock can be recovered as monomers or oligomers. The acid has greatly improved the sugar solubility, e.g. at 180 °C the sugar recovery has been only 1.5% without acid, while by using 3 wt.% of acid the sugar recovery has increased to 16.8%. Also the cellulose digestibility has been improved by the acid pre-impregnation, after 48 h of digestion the yield of glucose reached 93% of the theoretical by using the substrate that was pre-impregnated with 3 wt.% of acid an treated at 190 °C. The high acid loading has also been required to achieve the best recovery of glucose (85% of the initial glucan) as sum of water extraction and 48 h hydrolysis.

Processing cereal straws by steam explosion in a pilot plant to enhance digestibility in ruminants

Wheat, barley and oat straws were treated by steam explosion (SE) and then washed with 50 g/l NaOH solution. The SE treatment was optimized at batch scale on the basis of carbohydrate recovery. Stocks of fodder (300 kg) were produced at 198 °C for 2.5 min by a continuous reactor and used for in vivo digestibility tests carried out on sheep. The flow-sheet and the mass balances were obtained for the entire process. For the three straws, the water consumption has been 7.3 kg/kg of straw. To delignify and improve the digestibility of the straws, 20 g of NaOH/kg straw was used. The yield of fodder, lignin and hemicellulose is dependant on the nature of the starting straw. Delignified fodder (insoluble fraction) can be produced with a yield of 0.64, 0.59, 0.55, respectively, from wheat, barley and oat straw. SE improved the digestibility of the straw by 25%; alkaline washing further increased it by 9%. Balanced rations containing, on a DM basis, 1/4 of treated straw, had digestibility coefficients similar to those of commercial rations based on alfalfa.

Coupled acid and enzyme mediated production of microcrystalline cellulose from corn cob and cotton gin waste

Microcrystalline cellulose has applications in food, pharmaceuticals, and other industries. Most microcrystalline cellulose (MCC) is produced from dissolving pulp using concentrated acids. We investigated steam explosion treatment of corn cobs and cotton gin waste for the production of microcrystalline cellulose. The corn cob was converted into a coarse brown powder after steam explosion and the lignin and residual hemicellulose fractions were extracted respectively with sodium hydroxide solution and water. The residual cellulose was readily bleached with hydrogen peroxide and converted to microcrystalline cellulose using hydrochloric acid, sulfuric acid and cellulase enzyme preparation. The resulting microcrystalline cellulose samples had properties that were similar to commercial microcrystalline cellulose. Similarly, cotton gin waste was steam exploded and converted into microcrystalline cellulose, but this material was more difficult to bleach using hydrogen peroxide. The degree of polymerization for the MCC samples ranged from 188.6 to 549.8 compared to 427.4 for Avicel PH101 MCC.

Physiological Function of Insoluble Dietary Fiber Prepared from Exploded Oak Wood (Quercus mongolica)

This study investigated the production of insoluble dietary fiber using exploded and chemically treated oak wood (Quercus mongolica) and the physiological functions of prepared insoluble dietary fiber in laboratory animals. To produce high quality insoluble dietary fiber, the steam explosion treatment was performed at 25 kgf/cm2 pressure for 6 minutes. In the chemical analysis of insoluble dietary fiber, exploded oak wood was pretreated by 1% sodium hydroxide solution. The insoluble dietary fiber contained 7.6% residual lignin and 61.7% of alpha-cellulose. In order to compare the physiological functions of prepared insoluble dietary fiber with those of commercial insoluble dietary fiber, Sprague-Dawley male rats weighing 100 +/- 10 g were randomly assigned to one normal diet and five high cholesterol diets, containing 1% cholesterol. The high cholesterol diet groups were classified as the fiber-free diet (FF group), 5% commercial alpha-cellulose diet group (5C group), 10% commercial alpha-cellulose group (10C group), 5% insoluble dietary fiber group (5M group) and 10% insoluble dietary fiber group (10M group). Food intake, weight gain and food efficiency ratio in high cholesterol groups were significantly higher than those of the normal group, but there were no significant differences among the high cholesterol diet groups. In addition, there were no significant differences in the weights of liver, kidney and small intestine in insoluble dietary fiber-supplemented groups. Cecum weights in all insoluble dietary fiber groups were significantly higher than those of the FF group. There were no significant differences in the activities of the glutamic pyruvic transaminase (GPT) and glutamic oxaloacetic transaminase (GOT) among the insoluble dietary fiber-supplemented groups. In conclusion, the prepared insoluble dietary fiber and the commercially available insoluble fiber showed the same physiological effects. Moreover, the preparation method for the insoluble dietary fiber from the exploded oak wood was successful.

Production of methane gas from Japanese cedar chips pretreated by various delignification methods

Methane fermentation of woody waste was carried out using various pretreatment methods for delignification in order to evaluate the efficient pretreatment method for producing methane gas from woody waste. Japanese cedar ( Cryptomeria japonica) chips were used as sample of woody waste. As pretreatment methods, refiner treatment, steaming treatment, steaming treatment followed by refiner treatment, basidiomycete fungi treatment, and steam explosion treatment were attempted and the methane gas evolved from treated wood chips were compared. The steam explosion treatment resulted in the most effective pretreatment method for methane fermentation from woody waste among the pretreatment methods. The steam explosion at a steam pressure of 4.51 MPa and a steaming time of 5 min was the optimal pretreatment method for obtaining a large amount of methane gas in energy saving manner. The strong correlation between the amount of methane gas evolved and the ratio of amount of Klason lignin was observed. The study confirmed the necessity of pretreatment for delignification of cedar wood waste.

Effects of steam explosion on the chemical composition and rumen degradability of rice (Oryza sativa L.) straw

AbstractChanges in the chemical composition and in vitro degradability of rice (Oryza sativa L.) straw were examined for effects of steam explosion applied at 12, 16, 20, 24, and 28 kgf/cm2 pressure on rice straw. Physical breakdown of the straw with treatment was observed on most fractions of the particle size. These treatments also decreased (P < 0.05) organic matter and cell wall constituents, such as organic cell walls and neutral detergent fiber contents in the straw, as determined by enzymatic and detergent procedures. In contrast, the acid detergent lignin and acid detergent fiber contents increased (P < 0.05) with increasing steam pressure. The ultraviolet absorbance spectra of water‐soluble extracts in 28 kgf/cm2‐treated straws showed a maximal peak of 0.91 and a shoulder peak of 0.45 around 280 nm and 320 nm, respectively, increasing the maximal absorbance in accordance with the increase in steam pressure. Thus, at the lowest steam pressure, the microbial degradation of rice straw was increased as shown by the results of gas fermentation and volatile fatty acid production. Results in the present study indicate the possibility of improvement of nutritive value of cereal straw using a mild steam explosion treatment, compared to high steam conditions which can dangerously increase insoluble residual substances toxic to rumen microbes in the exploded roughages.

Production of L-Lactic Acid from Spent Grain, a By-Product of Beer Production

L-lactic acid production from spent grain with immobilized lactic acid bacteria was investigated. Spent grains were liquefied by a steam explosion treatment to obtain liquefied sugar. When 1 kg of wet spent grain was treated under the 30 kg/cm2pressure for 1 min using a 5-L steam explosion reactor, 60 g of total sugar was obtained from the liquefied spent grain. Furthermore, 1.3% (w/v) of glucose, 0.4% (w/v) of xylose, and 0.1% (w/v) of arabinose were produced when the liquefied spent grain was treated with glucoamylase, cellulase, and hemicellulase enzymes. When batch L-lactic acid production was carried out by Lactobacillus rhamnosus NBRC14710, 19.0 g/L L-lactic acid was produced from the Tween 80 liquefied spent grain after 5 days. Furthermore, during repeated batch production with immobilized Lactobacillus rhamnosus NBRC14710 from Tween 80 liquefied spent grain at 37°C, the productivity of L-lactic acid was maintained at a 10 time higher level over a period of 40 days.

Effect of steam explosion treatments on drying rates and moisture distributions during radio-frequency/vacuum drying of larch pillar combined with a longitudinal kerf

This study was carried out to investigate the effects of steam explosion treatment on drying rates, moisture distribution, shrinking, and checking during radio-frequency/vacuum drying of Korean larch pillar combined with a longitudinal kerf. All the pillars except the nonkerf/control with high initial moisture content (MC) could be dried within 89 h from the green condition to about 15% MC. In pillars with high initial moistures or in the early stage of drying, the drying rates were sharply accelerated by steam explosion treatments. The final moisture gradients along the transverse direction were gentler for the steamexploded pillars and for pillars with a longitudinal kerf, respectively, than for the unexploded pillars and for pillars without a longitudinal kerf. The moisture gradients along the longitudinal direction on all the layers were gentler for the pillars with a longitudinal kerf than for those without the kerf. Formation of checking was significantly controlled in the pillars with a longitudinal kerf. All the steam-exploded pillars except the kerf/1-cycle, however, were more severely damaged by checks than the unexploded pillars. A prong test revealed an extremely low level of residual stress for all the dried pillars.

Preparation of Insoluble Dietary Fiber from Forest Waste and Its Physiological Function in Rat Fed High Cholesterol Diets

This study investigated the production of insoluble dietary fiber using forest waste, the dietary effect of manufactured insoluble fiber on physiological function in rat fed high cholesterol diets. Insoluble dietary fiber was prepared from the wood chips of oak (Quercus mongolica). The best condition for steam-explosion treatment for the preparation of insoluble dietary fiber was 25 kg/㎤ pressure for 6 minutes. In the chemical analysis of insoluble dietary fiber pretreated by 1% sodium hydroxide solution with steam-exploded wood, α-cellulose content was 61.7% in the insoluble dietary fiber, which contained 7.6% residual lignin. In order to compare insoluble dietary fiber with commercial α-cellulose of physiological function, Sprague-Dawley male rats weighing 100±10 g were randomly assigned to one normal diet, five high cholesterol diet containing 1% cholesterol. The high cholesterol diet groups were classified as fiber free diet (FF group), 5% commercial α-cellulose diet (5C group), 10% commercial α-cellulose (10C group), 5% insoluble dietary fiber diet (5M group),, 10% insoluble dietary fiber (10M group). The rats were fed ad libidum for 4 weeks. Food intake, weights gain,, food efficiency ratio in high cholesterol groups were higher than those of normal group, but there were no significant differences between the experimental groups. There were not any significant differences in the weights of liver, kidney,, small intestine of insoluble dietary fiber supplemented groups, but weight of cecum in all insoluble dietary fiber group were significantly higher than those of FF group. A gastrointestinal transit time was decreased by supplementation of insoluble dietary fiber. Weight, water contents of feces in the insoluble dietary fiber supplemented groups were significantly higher than those of the FF group. There were not any significant differences in the activities of the glutamic pyruvic transaminase (GPT), glutamic oxaloacetic transaminase (GOT) between the experimental groups. In conclusion, the manufactured insoluble dietary fiber, commercial insoluble fiber have the same physiological effects. The preparation method of the insoluble dietary fiber from the oak chips suited its purpose.