Effect Of Steam Explosion Research Articles

Effect of Steam Explosion on the Structure, Chemical Composition and Pyrolytic Volatile Composition of Tobacco Waste

Tobacco stems are an important part of the tobacco leaf, containing a lot of cellulose, result in the low utilization of tobacco leaves in cigarettes. The pre-treatment technology of tobacco stems is a key to increase the utilization of tobacco stems. In this work, steam explosion treatment was carried out on tobacco stems with different moisture contents containing 2%, 5% and 10%, respectively. The steam explosion is carried out under different pressure and pressure holding time conditions, the changes in physical structure, chemical composition and pyrolysis volatiles of tobacco stem was investigated. The results indicate that steam explosion has a negligible impact on the crystalline structure of cellulose and low-order polysaccharide crystals, while it has an obvious effect on KCl. Steam explosion increases the specific surface area by destroying the amorphous structure on tobacco stems. The contents of chemical constituents and pyrolytic volatiles indicate that there is a significant leaching effect of lignin, but no change in cellulose content. Soluble polysaccharides, the main component of hemicellulose, were converted into pyrolytic volatiles e.g., furfural and furfuryl alcohol. In conclusion, the technology of steam explosion promotes the leaching, decomposition and chemical transformation of amorphous structures on tobacco stems, thus destroying the structure of the cell walls.

Effect of steam explosion and silanization of hemp fibers on polylactic acid biocomposites; analysis of mechanical-thermal properties and fungal biodegradation

Alkaline pretreated hemp fibers were modified by steam explosion and/or silanization before being compounded with polylactic acid (PLA). The fungal biodegradation of the PLA/hemp fibers composite was investigated using Aspergillus niger TISTR 3153 in an aqueous medium for 28 days, following the ISO 846: 1997 standard method. The influence of the different physicochemical modifications of hemp fibers on the fungal biodegradation of the composite was evaluated in terms of molecular weight, chemical structure, mechanical properties, thermal properties, and hygroscopic properties. The results showed that the modulus of all composites were averagely increased by 109%, compared to neat PLA. All the PLA/hemp fiber composites better retained their properties after fungal biodegradation than neat PLA. Therefore, the physicochemical treatments of fibers after alkaline pretreatment promoted the resistance of the composite to fungal biodegradation. The treatment of hemp fibers in the present work was alkalization followed by silanization, which resulted in a PLA-based composite that was suitable for outdoor applications.

Effect of steam explosion on the morphological, textural, and compositional characteristics of betel nut.

To reduce the adverse physical effects on the oral mucosa caused by excessive hardness of betel nut fibers, steam explosion was used to soften betel nuts. The effect of three operating parameters (pressure holding time, explosion pressure, and initial moisture content) on the morphology, texture, and chemical composition of the betel nuts was investigated. The fiber hardness and Shore hardness decreased by 56.17%-89.28% and 7.03%-34.29%, respectively, and the transverse tensile strength and fiber tensile strength also decreased by up to 60.72% and 24.62%, respectively. Moreover, the coefficient of static friction and moisture content increased. After steam explosion, the betel nut increased in transverse diameter, became darker and more yellow-red in color, and showed a damaged microstructure. The contents of free phenol and alkaloids decreased after steam explosion treatment, with free phenols and total alkaloids decreasing from 34.32 mg(GAE)/g and 7.84 mg/g to 21.58 mg(GAE)/g and 6.50 mg/g, respectively, after the A-50 s treatment condition. The steam explosion increased the quantity of phenols, alkaloids, and soluble solids released from the betel nut under the same simulated release conditions of the texture analyzer. The research also showed that increased pressure holding time and explosion pressure enhanced the explosion efficiency, while the initial moisture content was reduced the explosion efficiency. Therefore, steam explosion is an effective pretreatment approach to soften betel nut and facilitate healthy development of the betel nut industry.

Wheat bran fractionation: Effect of steam explosion and hydrotropic extraction conditions on the recovery of sugars and lignin

Wheat bran, a major by-product of wheat processing, contains several valuable components that can serve as a potential feedstock for chemical production. This study presents a multiple-stage fractionation method, involving steam explosion and hydrotropic extraction, which were investigated with the goal of separating the main structural bran components: starch, protein, hemicelluloses, lignin, and cellulose. With prior de-starching and de-proteination, acid-catalysed steam explosion (STEX1: 218 °C, 8 min, 0.05 wt% H2SO4) solubilised up to 97% of the arabinoxylans. Higher monosaccharide yields arising from hemicelluloses were observed in the de-starched and de-proteinated bran than in untreated bran prior to steam treatment. Subsequent treatment using the 40% w/w hydrotrope solution, sodium xylene sulfonate (SXS), at 170 °C for 1 h (HEX1) showed lignin recovery of up to 42.6% from the steam-exploded bran, which was higher than 25.1% lignin recovery from the de-starched, de-proteinated and steam exploded bran. The lignin recovery values were slightly underestimated as some lignin ends up in the wash, which proved difficult to quantify. Finally, glucose monomer release during cellulose hydrolysis occurred most rapidly in the bran material that had undergone prior treatments of de-starching, de-proteination, steam explosion and hydrotropic treatment, with complete hydrolysis in less than 24 h for the de-starched, de-proteinated, steam exploded for both STEX1 and STEX3 (219 °C, 0.10 wt%, 14 min) and hydrotropically treated (HEX1). The selective release of wheat bran components in separate stages of the wheat-bran fractionating scheme provides a platform for further valorisation of each component into commercially relevant products. Structural elucidation of the recovered wheat bran lignin using 2D HSQC NMR revealed that oxidised syringyl (S′) units increased from 13.2 units per 100 C2 aromatic group (Ar) in bran without prior treatment, to 16.9 units/100 Ar in steam exploded bran and 18.2 units/100 Ar in de-starched, de-proteinated and steam exploded bran. The change in guaicyl (G) unit frequencies as well as the oxidised G units (G′) remained low across samples. As less oxidation is desired for further lignin valorisation, the results herein offer insights on future work for utilising wheat bran lignin.

Effect of steam explosion on nutritional components, physicochemical and rheological properties of brown rice powder.

Brown rice powder is underutilized mainly due to its lower starch digestibility and poor processing performance. The present study investigated the potential of steam explosion on the improvement of nutritional and physicochemical characteristic in brown rice powder and rheological property of paste. Compared with native brown rice powder, steam explosion at 0.5 MPa for 7 min increased the water-extractable arabinoxylans (5.77%), reducing sugar content (21.04%), and iodine blue value (30.38%), which indicated steam explosion that destroyed the intact cells of brown rice. Later the crystalline structure of brown rice powder was destroyed into an amorphous structure by steam explosion. Steam explosion enhanced the degree of gelatinization (4.76~351.85%) and solvent retention capacity (SRC) of brown rice powder, compared with native sample. The effect on the intact cells and starch structure of brown rice caused the starch digestibility enhancement remarkable. Viscoelastic profiles confirmed that steam explosion weakened the paste strength and elasticity corresponded with hardness and cohesiveness by increasing the loss factor (tanδ). This work provided important information for brown rice powder modified by steam explosion (0.5 MPa, 7 min) with good nutritional property (nutrients and digestibility) and processability (SRC, textural, and rheological property). Steam exploded brown rice powder (0.5 MPa, 7 min) could serve as a potential ingredient widely used in food products.

Influence of thermochemical activation of wood on the physicochemical properties of lignin

The wood matrix is a lignin–carbohydrate nanobiocomposite, thermodynamically quasi-equilibrium heterogeneous system of biopolymers. Changing its thermodynamic equilibrium due to directed chemical and (or) physical impacts opens up new approaches to the study of plant objects. Thermochemical activation, including treatments in sub- (steam explosion) and supercritical conditions (supercritical fluid extraction) having similar mechanisms of action, is one such method. The effect of steam explosion is determined by two components — chemical (the catalytic effect of formed acetic and formic acid) and physical (a sharp adiabatic expansion). The main components of supercritical treatment are increased temperature and pressure in the CO2 medium with cosolvents. The chemical component of this treatment is due to the addition of chemical reagents. Such treatments lead to a change in the thermodynamic state and capillary-porous structure of the lignin–carbohydrate matrix, an increase in its heterogeneity, and the yield of extracted lignin preparations. Lignin is the most reactive component of the wood matrix, and these processes result in changes in its functional nature and reaction properties. Thus, the lignin sample extracted after steam explosion had the greatest increase in the content of phenolic hydroxyl (by 39 rel.%) and carboxyl (by 57 rel.%) groups. Change in the functional composition of lignin leads to a change in its redox state, characterized by the oxidative potential and free energy of oxidation. It was shown that lignin after steam explosion had the highest oxidative potential and the lowest value of the oxidation energy, which indicated the greatest change in its reactivity in redox interactions.

Improving Antioxidative and Antiproliferative Properties Through the Release of Bioactive Compounds From Eucommia ulmoides Oliver Bark by Steam Explosion.

Eucommia ulmoides Oliver bark is a potential medicinal plant-based feedstock for bioactive products and possesses the effective functions of antioxidant and antitumor. Network pharmacology was employed to reveal the oxidative and free radical damage and cancer-related potential compounds of Eucommia ulmoides Oliver in this study. The result showed that quercetin might be the key compound to resist these two types of diseases. Then, the effect of steam explosion on the release of bioactive compounds and the antioxidative and antiproliferative properties of the extract from Eucommia ulmoides Oliver bark were investigated. Results showed that steam explosion at 0.7 MPa for 30 min significantly enhanced the total phenolic, total flavonoids, and quercetin content of Eucommia ulmoides Oliver bark. Reducing power and 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) radical scavenging activity of the steam-exploded extracting solution were 1.72 and 2.76 times of native. The antiproliferative activity to CT26 and HepG2 of the extract from steam-exploded Eucommia ulmoides Oliver bark (SEU) was higher than those of native-exploded Eucommia ulmoides Oliver bark (NEU). All these results suggested that steam explosion could be applied to release the bioactive compounds, thus enhanced the antioxidative and antiproliferative activities of medicinal and edible plant-based sources.

Effect of Steam Explosion on Structural Characteristics of β-Conglycinin and Morphology, Chemical Compositions of Soybean Meal.

In this study, steam explosion was applied as a means to degrade β-conglycinin. We investigated changes in morphology, the chemical composition of soybean meal, and the structural characteristics of β-conglycinin. The results showed that steam explosion at 0.7 MPa for 8 min could effectively decrease the β-conglycinin content of soybean meal while the histamine content was not increased. The structural characteristics of soybean meal proteins were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), Fourier transform infrared spectroscopy (FTIR), circular dichroism (CD), and X-ray diffraction (XRD). Steam explosion caused the degradation of high weight proteins and reduced the band density of α’, α, and β subunits in β-conglycinin. The micro-surface of soybean meal seemed to be in the cracked or puffed stage and the color became brown or dark after steam explosion. Steam explosion facilitated the dissolution of water-extractable arabinoxylans, which are 4.81 fold higher than that of native soybean meal. Phytic acid was exposed to the hydrothermal environment of the steam explosion process and consequently degraded by 12.95–24.69%. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of soybean meal extract was gradually increased from 20.70 to 33.71% with the rising of treated pressure from 0.3 to 0.7 MPa, which was 1.11–1.81 fold of native extract. The steam explosion may be a new modification technology that could decrease antigenicity, and steam-exploded soybean meal (0.7 MPa, 8 min) with lower β-conglycinin and phytic acid content that could be widely used in food products.

Effect of Semi-Continuous Anaerobic Digestion on the Substrate Solubilisation of Lignin-Rich Steam-Exploded Ludwigia grandiflora

In this study, semi-continuous anaerobic digestion of lignin-rich steam-exploded Ludwigia grandiflora (Lignin = 25.22% ± 4.6% total solids) was performed to understand better the effect of steam explosion on the substrate solubilisation and inhibitors formation during the process. Steam explosion pretreatment was performed at 180 °C for 30 min at a severity factor of 3.8 to enhance the biogas yield of the lignocellulosic biomass. The semi-continuous anaerobic digestion was performed in a continuously stirred tank reactor for 98 days at an initial hydraulic retention time of 30 days and an organic loading rate of 0.9 g-VS L−1 day−1. The performed steam explosion pretreatment caused biomass solubilisation, resulting in enhanced biogas production during the process. During the anaerobic digestion process, the average biogas yield was 265 mL g-VS−1, and the pH throughout the operation was in the optimum range of 6.5–8.2. Due to fluctuations in the biogas yield, the hydraulic retention time and organic loading rate were changed on day 42 (50 days and 0.5 g-VS L−1 day−1) and on day 49 (40 days and 0.7 g-VS L−1 day−1), and 1 M of NaOH was added to the liquid fraction of the steam-exploded L. grandiflora during the latter part of the operation to maintain the stability in the reactor. Therefore, the steam explosion pretreatment helped in the degradation of L. grandiflora by breaking the lignocellulose structure. In addition, changes in the operating conditions of the anaerobic digestion led to an increase in the biogas production towards the end of the process, leading to the stability in the CSTR.

Effect of steam explosion on enzymatic hydrolysis of various parts of poplar tree

Effect of steam explosion on enzymatic hydrolysis of various parts of poplar tree

Effect of steam explosion on nutritional composition and antioxidative activities of okra seed and its application in gluten-free cookies.

Health‐conscious consumers are increasingly interested in gluten‐free (GF) foods. Raw okra seed (ROS) flour and steam‐exploded okra seed (SEOS) flour were explored for developing GF cookies with high nutritional values and in vitro enzymatic digestion. Results indicated that the steam explosion exhibited significant effects on enhancing the release of dietary fibers and lipids in okra seed flour at moderate explosion pressure. Although steam explosion caused the loss of flavonoid compounds, moderate high explosion pressure enhanced the release of total phenolics ranged from 294.57 to 619.07 mg GAE/100 g DM with significantly improved DPPH• radical scavenging activity (from 18.78% to 67.34%) and ferric reducing antioxidant power (from 13.37% to 149.04%). The rapidly digestible starch (RDS) content in GF cookies decreased with increasing steam explosion severity, whereas slowly digestible starch (SDS) and resistant starch (RS) contents significantly increased from 36.91% to 40.92% and from 2.50% to 9.06%, respectively. Steam explosion is an effective technique for enhancing the release of nutrients like dietary fiber and total phenolics, and okra seed flour, especially SEOS flour, can be alternative choices to provide food functional materials for developing various GF food products.

Effect of steam explosion of oil palm frond and empty fruit bunch on nutrient composition and ruminal fermentation characteristics

In this study, we evaluated the effect of steam explosion of oil palm frond (OPF) and oil palm empty fruit bunch (EFB) on nutrient composition and ruminal fermentation characteristics in vitro. The results showed that steam explosion decreased NDF (P < 0.01), ADF (P < 0.01), and hemicellulose content (P < 0.01) in OPF and EFB. Steam explosion improved the effective energy value of OPF and EFB. In vitro fermentation results revealed that 72-h gas production capacity of OPF and EFB increased by 12.60and 85.06% (P < 0.01), respectively, after steam explosion. Steam explosion had a tendency to improve the concentration of total volatile fatty acids (TVFA) (P = 0.082). In conclusion, steam explosion of OPF and EFB reduced NDF, ADF, and hemicellulose content and increased gas production and TVFA concentration.

Effect of steam explosion on dietary fiber, polysaccharide, protein and physicochemical properties of okara

Okara is the byproduct of tofu and soymilk industries. A large amount of okara is produced annually in the world, but only a small amount is fully utilized. The effect of steam explosion (SE) treatment on dietary fiber, protein and physiochemical properties of okara was investigated in this paper. The results showed that untreated okara contained 76.38% total dietary fiber (TDF) and 18.10% protein, but the content of soluble dietary fiber (SDF) was only 1.34%. After SE treatment, SDF content increased significantly. When the SE strength was 1.5 MPa for 30s, SDF content increased to 36.28%, higher by 26 times compared to the control okara. However, the contents of TDF and SDF both decreased when the SE strength enhanced further. Gel filtration chromatography showed that molecular weight of okara polysaccharides were distributed from 55 KDa to 2087 KDa. With the increase of SE strength, the ratio of low molecular weight polysaccharides increased and the molecular weight range of polysaccharides became narrower. Okara protein showed two molecular weight peaks. After SE treatment, the area of high molecular weight peak decreased and low molecular weight peak increased. Sodium dodecyl sulfate polyacrylamide gel electrophoresis showed that okara protein appeared in five bands: 73.7 KDa, 55 KDa, 41.1 KDa, 32.7 KDa and 20.2 KDa. After SE treatment, the bands of 73.7 KDa, 55 KDa and 41.1 KDa weakened markedly, indicating high SE strength can dissociate macromolecular protein aggregates. Water solubility of okara increased significantly, while swelling capacity, oil and water holding capacities decreased after SE treatment. Scanning electron microscopy (SEM) demonstrated that the loose sheet structure of okara surface was destroyed into small fragments after SE treatment and the internal nucleated structure was disintegrated into small particles at high SE strength. The change in morphological structure also produced important influences on physiochemical properties of okara. This study suggested that SE treatment is an effective method for improving SDF content and quality of okara, so as to expand its development and utilization.

Effects of steam-exploded wood as an insoluble dietary fiber source on the performance characteristics of broilers

Effects of modified insoluble fiber originating from steam-exploded Quercus mongolica were studied relative to growth performance, blood parameters, intestinal morphology, and other intestinal characteristics in poultry broilers. First, the effect of steam-explosion on physicochemical properties of insoluble fiber from Q. mongolica was investigated. Steam-explosion (severity factor Log (Ro) = 3.94) was found to increase the physical properties (water-holding capacity, oil-holding capacity, and swelling capacity) of Q. mongolica chip to different extents. Effects of feeding different concentrations of steam-exploded Q. mongolica on performance characteristics of broilers were investigated. Experimental diets of broilers consisted of a control diet (free of steam-exploded Q. mongolica), and four diets containing 0.5% to 2.0% steam-exploded Q. mongolica (severity factor Log (Ro) = 3.94). A diet containing 1.0% steam-exploded Q. mongolica promoted broiler growth performance (body weight (858.9 g) and improved blood characteristics (130.0 mg/dL), intestinal morphology (V:C ratio 7.50), and organ weights (length of intestine 17.6 cm/100 g body weight).

Suppression Effect of Steam Explosion with Carbon Dioxide Dissolved

Suppression Effect of Steam Explosion with Carbon Dioxide Dissolved

Effect of steam explosion on the structural modification of rice straw for enhanced biodegradation and biogas production

The goal of this study was to develop an operational steam explosion pretreatment for effective modification of rice straw chemical structure in order to improve its biodegradability and methane yield. The parameters of pressure (5 bar to 15 bar), moisture (0% to 70%), and time (1 min to 15 min) were studied in steam explosion pretreatment. The steam explosion efficiency was investigated according to the changes in crystallinity structure and chemical composition on rice straw, as well as the methane yield from straw. Steam explosion changed the structure linkages between the lignin and carbohydrate, which was indicated by a reduction in the peak intensities in the bonds from 1648 cm-1 to 1516 cm-1. After pretreatment, the crystallinity index of the rice straw in the 10 bar-10 min cycle with no moisture and 15 bar-10 min cycle with 70% moisture increased from 22.9% to 28.3% and 28.6%, respectively. Steam explosion efficiently decreased the lignin. The highest reduction in the amount of lignin was observed with the 10 bar-10 min cycle, which reached from 18.6% to 13.0%. The methane yield increased with the cycles 10 bar-10 min and 15 bar-15 min with 35% moisture, and 15 bar-10 min with 70% moisture by 113%, 104%, and 147% compared to that of the untreated straw, respectively. Moreover, the highest biodegradation percent of the rice straw was obtained in these cycles.

Effects of particle size, pretreatment, and catalysis on microwave pyrolysis of corn stover

The effects of particle size, pretreatment (acid pretreatment and steam explosion), and catalysis of aluminum oxide (Al2O3) on heating efficiency, product distribution, and gaseous product composition of corn stover pyrolysis using microwave heating were investigated in this study. Both maximum temperature and heating rate increased with decreasing particle size of corn stover. The heating efficiency was also improved over Al2O3 and by applying both pretreatment methods. Adding 10-mesh Al2O3 increased the gaseous yield but decreased the liquid yield. However, this phenomenon did not exist when 50-mesh Al2O3 was used. This may be attributable to that small catalyst particles are encapsulated by other catalyst and biomass particles to reduce their catalytic activity. Applying acid pretreatment substantially decreased the gaseous yield but increased the liquid yield, whereas the effect of steam explosion was not significant. Approximately half of CO was produced during the first 5 min of experiment, but the yields of H2, CH4, and CO2 produced from microwave pyrolysis of corn stover pretreated by acid were relatively small or even none during this initial period. The reaction kinetics for microwave pyrolysis of corn stover was analyzed by using the first- and second-order reaction models.

Lattice Boltzmann simulations of diffusion through native and steam-exploded softwood bordered pits

Bordered pits connect adjacent tracheid cells in softwoods and enable water transport between them. Knowledge of how large molecules, such as polysaccharides and enzymes, are transported through pits is important to understand the extraction process of valuable biopolymers from wood. The main mass transport mechanism for large dissolved molecules in wood is diffusion, and this is investigated through mathematical modeling in the lattice Boltzmann framework utilizing SEM images and 3D reconstruction of an actual bordered pit to compute an effective diffusion coefficient. Confocal laser scanning microscopy is used to find the unobstructed diffusion coefficients in a free aqueous solution using fluorescent diffusion probes of dextran. The effect of steam explosion on pit structure is explored through the use of a simplified model. The importance of different components of a bordered pit is investigated using simulation data, and results show that the most important structural features are the borders. Expressions for the effective diffusion coefficient as a function of the free diffusion coefficient are presented for a native and for a steam-exploded pit, respectively.

Effect of steam explosion on solid-state fermentation of maize stalk by Penicillium decumbens and Phanerochaete chrysosporium for animal feed production.

Pre-treated maize stalk could be used for animal feed due to the improved digestibility. Steam explosion (SE) and solid-state fermentation (SSF) are two methods in maize stalk pre-treatment. To evaluate the effect of combination of SE and SSF on the maize stalk pre-treatment, the maize stalk was treated with steam explosion and microbial fermentation with Penicillium decumbens and Phanerochate chrysporium in this study. The steam explosion severity (logR0 ) affected component of the corn stover and then affected the SSF. The highest weight loss of substrate (23.20%), protein (12.71%) and cellulase filter paper activity (FPA) (7.42IU/g) could be obtained at logR0 =3.64 and the IVDMD of SE-SSF-treated straw could reach 75.8%. The SE-SSF pre-treatment method could improve the utilization of straw as animal feed and overcome the shortage of feed source in animal husbandry.

Effect of steam explosion on enzymatic hydrolysis and baking quality of wheat bran

In this study, the effect of steam explosion (SE) treatment on microstructure, enzymatic hydrolysis and baking quality of wheat bran was investigated. Coarse and fine bran were treated at different steam temperatures (120–160 °C) and residence times (5 or 10 min) and then hydrolysed with carbohydrase enzymes. The SE treatment increased water extractable arabinoxylan (WEAX) content from 0.75 to 2.06% and reducing sugars from 0.92 to 2.41% for fine bran. The effect was more pronounced with increased SE temperature and residence time. The highest carbohydrate solubilisation was observed in fine bran at SE treatment of 160 °C, 5 min. WEAX content increased to 3.13% when this bran was incubated without enzyme, while WEAX content increased to 9.14% with enzyme addition. Microscopic analysis indicated that cell wall structure of wheat bran was disrupted by severe SE conditions. Supplementation of SE treated (150 °C, 10 min) bran at 20% replacement level decreased the baking quality of bread. However SE followed by enzymatic hydrolysis increased specific volume and decreased crumb hardness (on the day of baking and after three days of storage). Phytic acid content of bread supplemented with SE treated bran was lower than the one supplemented with untreated bran.