Steam Explosion Pretreatment Research Articles

Pressure-controlled steam explosion as pretreatment for efficient extraction of Tremella fuciformis polysaccharide: Structure and bioactivity

Tremella fuciformis (TF) is a mushroom with rich nutritional and medicinal value. This study aimed to develop an efficient extraction technique for TF polysaccharide (TFP) to enhance its health benefits. TF was subjected to steam explosion (SE) pretreatment at 0.5, 1.0, and 1.5 MPa for 60 s, followed by polysaccharide extraction. The extraction yield of TFP increased from 15.42 % to 50.16 % at 1.0 MPa. SE disrupted the dense structure of TFP, significantly improving total sugar and uronic acid contents, monosaccharide molar percentages of mannose and glucose, specific surface area, and ζ potential by 0.16, 0.4, 0.01, 0.83, 0.19, and 0.26 times at 0.5 MPa (P < 0.05). With increasing SE pressure, the thermal stability of TFP was enhanced, while its elasticity, viscosity, molecular weight, and particle size were reduced. TFP at 0.5 MPa significantly extended the lifespan of Drosophila melanogaster, with Tmax reaching 74 d for females and 60 d for males at a dosage of 0.015625 %, indicating a 0.32-fold enhancement. TFP enhanced climbing ability and antioxidant stress resistance, increased antioxidant enzyme activities and total antioxidant capacity, and reduced malondialdehyde levels, indicating its anti-aging effects. These findings provide theoretical and technical support for the high-value development and utilization of TFP.

Oil palm frond leaves (OPFLs), a high recalcitrant biomass as an alternative cellulose source for glucose conversion

Among the oil palm biomass, oil palm frond leaves (OPFLs) are under-valued since they can be classified as a high recalcitrance feedstock due to the high lignin and hemicellulose content. This work proposes a new way of using OPFLs as alternative cellulose sources for glucose conversion by an application of various pre-treatments at varying parameters. From green pre-treatment, steam explosion (SE) is much more effective in disrupting the OPFLs structure in contrast to hydrothermal (HT) pre-treatment, by a vast dissolution of hemicellulose and depolymerization of lignin. The pre-impregnation with H2SO4 prior to steam explosion was beneficial to enhance the hemicellulose removal up to 89.94 %. The 2D-HSQC NMR analysis divulged the reduction of ß-O-4 linkage and S/G value after the SE and HT pre-treatment, verifying the degradation of lignin-carbohydrate linkage in OPFLs. Meanwhile, the dilute NaOH pre-treatment enhanced the delignification by 87.14 %. SEM analysis revealed a well-disrupted structure of pre-treated OPFLs exposing a higher cellulosic fraction, whereas SEC analysis divulged a decreasing pattern of degree of polymerization of cellulose. The enzymatic analysis revealed that pre-treated OPFLs yielded higher glucose ranging from 29.81 % to 49.98 % w/w, which was ∼3-fold higher than raw OPFLs (14.31 % w/w). A maximum cellulose digestibility (100 %) was achieved by steam-exploded OPFLs after 72 h of enzymatic hydrolysis. This suggests the potency of various pre-treatments to enhance enzymatic saccharification of OPFLs producing a higher glucose yield.

The rolling-disc milling texture-sorting of raw straw facilitates the reduction of steam explosion intensity

Lignocellulosic fermentable sugars have been attracting increasing attention due to the developments of synthetic biology, yet the heterogeneity of the raw material results in high pretreatment intensities and the generation of numerous fermentation inhibitors. In this study, the rolling-disc milling texture-sorting was established for raw material to mitigate inhibitors generation at its source, specifically targeting the variances in mechanical strength among corn straw tissues. Through the texture-sorting of raw corn straw, the low modulus of elasticity tissues in corn straw were crushed into soft-texture sorts and the high-strength tissues were retained as hard-texture sorts. The results showed that the steam explosion pretreatment intensity required for soft-texture sorts decreased by 77.34 %, from 1125.96 (180 °C, 5 min) to 255.10 (160 °C, 5 min), compared to the hard-texture sorts. The concentrations of inhibitors in the enzymatic hydrolysate of soft-texture sorts decreased by 55.10 %, from 8.13 g/L/(100 g/L total sugars) to 3.65 g/L/(100 g/L total sugars), indicating an improved suitability for enzymatic hydrolysate preparation. Therefore, the rolling-disc milling texture-sorting method was proposed to provide a new approach for the preparation of lignocellulosic fermentable sugars.

Effect of steam explosion pretreatment on the fermentation characteristics of polysaccharides from tea residue

Green tea residues are the by-product of tea processing and they contain a large number of bioactive ingredients. Steam explosion has been recognized as one of the most innovative pretreatments for modifying the physicochemical characteristic of polysaccharides from lignocellulosic materials. However, the comparison of biological activity of steam exploded (SE-GTR) and unexploded (UN-GTR) green tea residue polysaccharides was still unclear, which prompted the determination of the efficacy of steam explosion in tea residue resource utilization. In this study, the effects of two extracted polysaccharides UN-GTR and SE-GTR on human gut microbiota in vitro fermentation were conducted. The results showed that after steam explosion pretreatment, SE-GTR displayed more loose and porous structures, resulting in higher polysaccharide content (2483.44±0.5 μg/mg) compared to UN-GTR (1903.56±2.6 μg/mg). In addition, after 24 h fermentation, gut microbiota produced more beneficial metabolites by SE-GTR. The largest SCFAs produced among samples was acetic acid, propionic acid and butyric acid. Furthermore, SE-GTR could regulate the composition and diversity of microbial community, increasing the abundance of beneficial bacteria, such as Bifidobacterium. These results revealed that steam explosion pretreatment could be a promising and efficient approach to enhance the antioxidant activity and bioavailability of polysaccharides isolated from tea residues.

Exploring the Impact of Steam Explosion Pretreatment on the Binding Characteristics of Coal-Biomass Briquettes: A Study on Lignocellulose Type and Fibre Morphology

AbstractThe urgency to shift from coal to renewable energy sources drives the need for innovative solutions. Steam exploded lignocellulose acting as both binder and fuel in coal-briquetting presents a pathway for this transition whilst utilizing waste coal-fines. However, the applicability of different industrially relevant feedstocks and their specific binding mechanism is unknown. In this study we assess the impact of treatment severity and explosion pressure on fibre properties and briquette tensile compressive strength (TCS) across four feedstocks (sugarcane bagasse (SCB), corn stover (CS), black wattle (BW), and pine). Lignocellulose was steam exploded at severities ranging from 3.53 to 4.71 and physical modifications due to explosion pressure was isolated by conducting explosive decompressions at pressures ranging from 3 to 22.5 bar. Briquettes, prepared using 18% by mass steam exploded lignocellulose as a binder, were quantified for TCS and results showed that as particle aspect ratio increased, so did TCS, regardless of lignocellulose type. For SCB, CS, and BW, high explosion pressure and low to moderate severity (3.5–3.8) produced the highest aspect ratios and, consequently, highest TCS (1288, 1181, 905 kPa respectively). However, at high severity and pressure, a reduction in aspect ratio was observed and, subsequently, TCS. Pine required high severity and pressure to produce barely acceptable briquette TCS (364 kPa), due to its low aspect ratio. Physical modification of fibre aspect ratio during steam explosion therefore played a crucial role in its binding performance in coal-briquettes and the relative success of SCB, CS and BW indicate that there are significant resources of lignocellulose available for this technology and allow for widespread industrial application. Graphical Abstract

Xylitol production by a Wickerhamomyces anomalus strain adapted for enhanced tolerance to sugarcane bagasse hemicellulosic hydrolysate with high content of fermentation inhibitors

BackgroundXylitol, a five-carbon polyalcohol, is used in the food and pharmaceutical industries and as a building block in the synthesis of high-value chemicals. It can be sustainably produced from renewable sources through xylose assimilating microbe fermentation. ResultsWe screened microbial strains for xylitol production and identified Wickerhamomyces anomalus Z1 as a key xylitol producer. Utilizing lignocellulosic biomass hydrolysates for xylitol production poses challenges due to microbial sensitivity to inhibitors from biomass pre-treatment. In this study, an adaptive laboratory evolution (ALE) of W. anomalus Z1 was performed by culturing the yeast in a mineral medium supplemented with gradual increases of sugarcane bagasse hemicellulosic hydrolysate (SCHH) obtained by intensified steam explosion pretreatment. The performance of the adapted yeast, named Wickerhamomyces anomalus ALE, was assessed in comparison to the wild-type strain regarding its capacity to produce xylitol using SCHH. The evolved yeast reached a xylitol yield of 0.11 g xylitol/g xylose whereas the wild-type strain could not produce xylitol. Removing acetic acid from SCHH enhanced W. anomalus ALE performance, with optimal results at 75% hydrolyzed hemicellulose, yielding 0.44 g xylitol/g xylose and 13.41 g/L xylitol. ConclusionsThis study demonstrates the potential of W. anomalus ALE in successfully valorizing the hemicellulosic fraction of sugarcane bagasse for sustainable xylitol production.How to cite: Bonfiglio F, Cagno M, Nuñez L, et al. Xylitol production by a Wickerhamomyces anomalus strain adapted for enhanced tolerance to sugarcane bagasse hemicellulosic hydrolysate with high content of fermentation inhibitors. Electron J Biotechnol 2024;71. https://doi.org/10.1016/j.ejbt.2024.05.004.

Investigation of the influence of Candida tropicalis on bioethanol production using sugarcane bagasse: stochastic and in silico analysis.

This study investigated the impact of Candida tropicalis NITCSK13 on sugarcane bagasse (SCB) consolidated bioprocessing (CSB) using various parameters, such as pH, steam explosion (STEX) pretreatment, and temperature (at two different temperatures, cellulose hydrolysis and ethanol fermentation). The backpropagation neural network (BPNN) method simulated the optimal CSB conditions, achieving a maximum ethanol yield of 44 ± 0.32g/L (0.443g of ethanol/g of SCB) from STEX pretreated SCB within 48h at 55°C for cellulose hydrolysis and 33°C for ethanol fermentation and pH 3.5. The simulated conditions were experimentally validated and showed an R2 value of 0.998 and absolute average deviation (AAD) of 1.23%. The strain NITCSK13 also exhibited a high ethanol tolerance of 16% (v/v). The interactions between the inhibitors, cellobiose, furfural, and thermocellulase were assessed through molecular docking. The results revealed a maximum inhibitory constant of 3.7mM for furfural against the endoglucanase (EnG) of Humicola insolens (2ENG) at 50°C. Acremonium chrysogenum endoglucanase (5M2D) exhibited a maximum of 88.7µM for cellobiose at 50°C. The SWISS homology model of EnG from Candida viswanathii exhibited inhibitory effects similar to those of EnG from Thermoascus and Thermotoga, indicating that the moderately thermophilic yeast Candida sp. cellulase may be capable of efficiently tolerating inhibitors and could be a promising candidate for consolidated bioprocessing of cellulosic ethanol.

Effects of steam explosion pretreatment on the digestive properties and gut microbiota of Laminaria japonica polysaccharide.

Laminaria japonica polysaccharide, which is an important bioactive substance of Laminaria japonica with anti-inflammatory and antioxidant effects. In this study, the molecular weight, functional groups and surface morphology were investigated to evaluate the digestive properties of Laminaria japonica polysaccharide before and after steam explosion. The results indicated that the Laminaria japonica polysaccharide entered the large intestine to be utilized by the gut microbiota after passing through the oral, gastric and small intestinal. Meanwhile, Laminaria japonica polysaccharide of steam explosion promoted the growth of beneficial bacteria Phascolarctobacterium and Intestinimonas, and increased the content of acetic, propionic and butyric acids, which was 2.29-folds, 2.60-folds and 1.63-folds higher than the control group after 48 h of fermentation. This study reveals that the effect of steam explosion pretreatment on the digestion in vitro and gut microbiota of Laminaria japonica polysaccharide will provide a basic theoretical basis for the potential application of Laminaria japonica polysaccharide as a prebiotic in the food industry. © 2024 Society of Chemical Industry.

Steam Explosion Pretreatment of Polysaccharide from Hypsizygus marmoreus: Structure and Antioxidant Activity.

This paper investigated the effects of steam explosion (SE) pretreatment on the structural characteristics and antioxidant activity of Hypsizygus marmoreus polysaccharides (HPS). Hypsizygus marmoreus samples were pretreated at different SE temperatures (120-200 °C) and polysaccharides were extracted using the water extraction and alcohol precipitation method. The results showed that SE pretreatment improved the extraction rate of HPS. Under the conditions of SE treatment time of 60 s and temperature of 160 °C, the extraction rate of HPS was the highest (8.78 ± 0.24%). After SE pretreatment, the structural changes of HPS tended to enhance the antioxidant activity, which showed that the content of Gal and Man in the monosaccharide composition increased and the molecular weight decreased. When testing antioxidant activity in vitro, the ability of SE-pretreated HPS to scavenge DPPH radicals, hydroxyl radicals, and superoxide anion radicals was better than that of HPS without SE pretreatment. Our findings shed light on SE pretreatment as an efficient method for extracting active polysaccharides, providing a new way to improve their extraction rate and biological activity.

Physicochemical properties of polysaccharides from Hericium erinaceus by steam explosion pretreatment and its effects on human gut microbiota

Crude polysaccharides (HEP) extracted from Hericium erinaceus (H. erinaceus) using hot water soaking were focused in this study. The effects of steam explosion (SE) pretreatment (against H. erinaceus raw material) on the physical and chemical characteristics and in vitro fermentability of HEP were examined. SE increased the yield, the total sugar content, and β-glucan content for HEP by 244.96%, 51.22% and 34.60%, respectively. SE treatment also reduced the molecular weight of HEP and released relative lower molecular fractions, as reflected by the elution profiles from HPSEC. During in vitro fermentation (by human feces) process, HEP from SE treated (HEQ) and untreated samples (HEW) both demonstrated capability in regulating gut microbiota (GM) by improving the abundance of beneficial bacteria such as Firmicutes and the production of short-chain fatty acids (SCFAs), while reducing the abundance of harmful bacteria such as Escherichia-shigella. Moreover, HEQ could increase the production of acetic, propionic and total SCFAs, while HEW could better increase the production of n-butyric acids. The findings of this study provide a reference for the efficient extraction and preparation of HEP, and highlighting its potential application in modulating GM.

Catalyst-recirculating system in steam explosion pretreatment for producing high-yield of xylooligosaccharides from oat husk

We propose a closed-loop pretreatment process, wherein volatiles produced during steam explosion pretreatment were recovered and reintroduced as acid catalysts into the pretreatment system. The volatiles were separated through a drastic decompression process followed by a steam explosion process and recovered as a liquified catalyst (LFC) through a heat exchanger. The LFC effectively served as an acid catalyst for hemicellulose hydrolysis, significantly decreasing residence time from 90 min to 30 min to achieve 80 % conversion yield at 170 °C. Hydrolysates with high content of lower molecular weight oligomeric sugars were obtained using LFC, and were considered advantageous for application as prebiotics. These results are attributed to the complementary features of acetic acid and furfural contained within the LFC. Computational simulation using Aspen Plus was used to investigate the effects of recycling on LFC, and it demonstrated the feasibility of the catalyst-recirculating system. A validation study was conducted based on simulation results to predict the actual performance of the proposed pretreatment system. Based on these results, the recirculating system was predicted to improve the conversion yield and low-molecular weight oligomers yield by 1.5-fold and 1.6-fold, respectively.

Enhancing the mechanical strength of corrugated medium paper through instant catapult steam explosion pretreatment of tobacco stem

The decline in mechanical properties of secondary fiber upon multiple recycling iterations necessitates the incorporation of cost-effective and environmentally friendly fibers to counterbalance strength loss. In this study, an orthogonal experiment design was employed to optimize the SE process to acquire tabocco stem pulp (TSP). The study systematically investigated the influence of steam pressure, residence time, and alkali dosage employed during impregnation were investigated. Notably, the research identified alkali dosage as the most significant parameter impacting system performance. Under optimized conditions (1.2 MPa, 5 min, and 5 %), the prepared paper using 100 % TSP exhibited the capability to attain Grade C corrugated medium. TSP, subsequently, served as a compensatory material for mitigating the loss of strength observed in low-quality secondary fibers (LSF). Remarkably, the introduction of 20 wt% TSP resulted in the production of grade B products, showcasing exceptional enhancement in ring-crush strength. The breaking length of paper was increased with an additional 0.5 wt% PAE added, resulting in all criteria achieving the highest grade A. In conclusion, the study elucidated the synergistic and complementary effects of TSP and LSF, wherein stiff TSP fiber bundles formed a network that effectively supported LSF filling. This study identified the relationship between SE parameters and fiber properties, conclusively establishing waste tobacco stem as a quality fiber source conducive to producing high-quality paper.

Advancing Thermophilic Anaerobic Digestion of Corn Whole Stillage: Lignocellulose Decomposition and Microbial Community Characterization

Converting corn grains into bioethanol is an expanding practice for sustainable fuel production, but this is accompanied by the production of large quantities of by-products such as whole stillage. In the present study, the influence of advanced wet oxidation and steam explosion (AWOEx) pretreatment on biogas production and lignocellulose decomposition of corn whole stillage (CWS) was evaluated using semi-continuous thermophilic reactors. The digestion of the CWS was shown to be feasible with an organic loading rate (OLR) of 1.12 ± 0.03 kg VS/m3 day and a hydraulic retention time (HRT) of 30 days, achieving a methane yield of 0.75 ± 0.05 L CH4/g VSfed for untreated stillage and 0.86 ± 0.04 L CH4/g VSfed for pretreated stillage, corresponding with an increase in methane yield of about 15%. However, the reactors showed unstable performance with the highest investigated OLRs and shortest HRTs. Under optimal conditions, the conversion efficiencies of COD, cellulose, hemicellulose, and lignin were 88, 95, 97, and 59% for pretreated CWS, and 86, 94, 95, and 51% for untreated CWS, respectively. Microbial community analysis showed that Proteiniphilum, MBA03, and Acetomicrobium were the dominant genera in the digestate and were likely responsible for the conversion of proteins and volatile fatty acids in CWS.

Steam explosion-assisted grinding improves the functional properties and antioxidant activity of Java tea-leaf powders (Clerodendranthus spicatus).

Java tea is widely consumed and has multiple health effects. This study established a steam explosion (SE) pretreatment method to prepare Java tea-leaf powders. The physicochemical, functional properties, phenolic extraction, and antioxidant activity of Java tea-leaf powders produced by simple and SE-assisted milling methods were investigated. In comparison with simple milling, SE pretreatment broke the cell wall effectively and reduced the particle size of Java tea-leaf powders. Steam explosion-treated powders showed higher values for sensory signals, bulk and tap density, and for the water solubility index. After SE treatment, the adsorption capacities to glucose, soybean oil, and cholesterol of leaf powders were increased by up to 55, 95, and 80% respectively. The extracts from SE-treated powders also showed higher total polyphenol content and antioxidant activity. Steam explosion treatment is helpful for the improvement of functional properties and antioxidant activity, which can benefit the development and application of Java tea-leaf powders. © 2024 Society of Chemical Industry.

Functional properties and structure of soluble dietary fiber obtained from rice bran with steam explosion treatment

Rice bran was modified by steam explosion (SE) treatment to investigate the effect of different steam pressure (0.4, 0.8, 1.2, 1.6, and 2.0 MPa) with rice bran through 60 mesh and rice bran pulverization (60, 80, and 100 mesh) with the steam pressure of 1.2 MPa on the functional properties and structure of soluble dietary fiber (SDF) from SE-treated rice bran. SE pretreatment enhanced glucose and cholesterol adsorption capacity, water-holding capacity, oil-holding capacity, lipase inhibition capacity and anti-oxidation properties of SDF. However, functional properties of SDF were adversely affected when steam pressure was 2.0 MPa or crushing degree of rice bran was 100 mesh. The results showed that some glycosidic and hydrogen bonds were broken, resulting in a porous honeycomb structure and decreased polymerization degree of the crystalline regions and relative crystallinity in SDF from SE-treated rice bran. In general, the optimum condition for obtaining better properties of SDF was treated for rice bran at the steam pressure of 1.2 MPa and sieve size of 60 mesh. This finding emphasizes essential information on SE treatment of rice bran in modifying the properties of SDF, which is helpful to the development and utilization of SDF from SE-treated rice bran.

Combination of steam explosion pretreatment and mixture design optimization as a strategy to enhance the antioxidant activity of crude polysaccharides isolated from edible mushrooms

The edible polysaccharides derived from mushrooms are bioactive fibers that possess great health benefits. In particular, the association between the antioxidant activity of polysaccharides and their beneficial health effects has sparked significant interest. There is a focus on exploring novel strategies to enhance the antioxidant activity of mushroom polysaccharides. In this study, the combination of steam explosion pretreatment (an environmental friendly and efficient biomass pretreatment method) and mixture design optimization was used to enhance the antioxidant activity of polysaccharides from two edible mushrooms i.e., Agrocybe aegerita (AaP) and Agaricus bisporus (AbP). We found that steam explosion pretreatment increased the yield of AaP and AbP polysaccharides by 2.47 and 1.91 times, respectively. In addition, the steam explosion was found to augment the antioxidant capacity of crude polysaccharides through structural alterations. Moreover, the combination of steam explosion pretreatment and mixture design optimization further augmented the antioxidant activity of two extracted polysaccharides at optimal ratio (AaP: AbP = 1:4) in vitro. In summary, a combination of steam explosion pretreatment and mixture design optimization could be a promising and efficient approach to enhance the antioxidant activity of polysaccharides isolated from multiple types of mushrooms.

Overcoming Softwood Recalcitrance by Improved 2-Naphthol Addition to Steam Explosion Pretreatment

Overcoming Softwood Recalcitrance by Improved 2-Naphthol Addition to Steam Explosion Pretreatment

Combined leaching and steam explosion pretreatment of lignocellulosic biomass for high quality feedstock for thermochemical applications

A novel pretreatment approach was developed in the present study to simultaneously reduce the content of inorganic troubling elements (TEs) and improve biomass energy density, i.e., combined leaching and steam explosion (SE) pretreatment with mechanical pressing. Three different high-ash-containing biomass feedstocks were studied – wheat straw (WS), spruce bark (SB), and empty fruit bunches of oil palm (EFB). Before studying the combined pretreatment, the impact of individual pretreatment was determined in-depth on biomass composition and ash-transformation behaviour. In leaching pretreatment, the effect of leaching with steam explosion condensate (SEC), dilute acetic acid and water was studied comprehensively. The solid (raw and treated) and liquid samples (leachate, SEC, hydrolysate) were characterized for a detailed comparative analysis. The ash-fusion and −transformation behaviour of raw and pretreated biomass was studied in-depth using advanced multicomponent thermodynamic equilibrium modelling (TEM) and push-rod dilatometry. After combined pretreatment, a considerably high reduction in TEs content was noted: 82–98 % K, 93–99 % Na, 80–99 % Cl, 34–90 % S, 3–77 % Mg, ash 43–63 %, 26–67 % P, and 19–63 % Ca. Simultaneously, heating values of all three feedstocks increased by 1.3–2.3 MJ/kg, reaching up to 20–22 MJ/kg. TEM results reveal that much lesser amounts of molten slag and volatile inorganic compounds were formed in pretreated samples compared to raw and SE biomass, such as K2Si5MgO12, KCl, KPMgO4, K2Si2O5, CaSiO3, and MgSiO3 in WS; Na2CO3, K2CO3, K2CaC2O6, KPMgO4, and CaCO3 in SB. Due to higher energy density and lower propensity towards ash-related issues, combined pretreated WS and SB have a high potential to be used in large-scale thermochemical applications.

The innovative extraction and purification process of insoluble polyphenols from Paeonia ostii roots: Optimum study and in vitro activities

The oil tree peony (Paeonia ostii) is widely cultivated for their high value seed oil, and its roots also have high medicinal value, but they are often discarded and wasted as by-products. In this study, a set of steam explosion (SE) and ultrasound (US)-assisted extraction/purification methods of insoluble bound phenols (IPs) from oil peony roots (PR) were explored and developed. The IPs were obtained through SE pre-treatment (120 °C, 15 min) and US-assisted alkaline extraction (0.25 W/cm2, 4 h and 4 M NaOH). Their total phenolic content (TPC) significantly increased from 112.26 mg gallic acid/g dry weight (mg GAE/g dw) with traditional method to 185.59 mg GAE/g dw. Subsequently, the IPs were purified into PIPs using LX-83 resin. The optimized purification conditions were pH = 4, 3.0 mg GAE/mL of IPs, 0.25 W/cm2 adsorption for 120 min, as well as 60 % ethanol desorption solution, and 0.25 W/cm2 desorption for 30 min. The TPC of the PIPs increased to 254.74 mg GAE/g dw. Notably, typical compounds in IPs and PIPs were identified and quantified by HPLC-MS and their antioxidant and anti-tyrosinase activities were also evaluated by chronometry. The results showed that paeoniflorin and benzoyl-paeoniflorin increased by about 10-fold in the PIPs. Additionally, they demonstrated superior antioxidant and tyrosinase inhibitory activities compared to IPs. Therefore, the innovative extraction and purification process greatly improved the yield of bound phenols and recovered paeoniflorin from non-medicinal PR. The process may also provide a reference for the in-depth development of medicinal PR, ultimately achieving more efficient PR development and utilization.

In vitro digestive properties of Dictyophora indusiata polysaccharide by steam explosion pretreatment methods

Dictyophora indusiata is medicinal and edible fungi containing various nutrients. The aim of this study was to investigate the efficient extraction and structural evolution of Dictyophora indusiata polysaccharide during the vitro digestion based on steam explosion pretreatment methods. In this study, the extraction rate of Dictyophora indusiata polysaccharide was optimized by steam explosion pretreatment methods, which was 2.46 folds that of the water extraction method. In addition, the digestion and fermentation properties of Dictyophora indusiata polysaccharide before and after steam explosion were evaluated in vitro by the changes of molecular weights, total and reducing sugars levels, surface morphology and functional groups, which showed that the structure of Dictyophora indusiata polysaccharide remained stable after salivary-gastric digestion, and partially entered the large intestine, where it could be utilized by gut microbiota. Dictyophora indusiata polysaccharide promoted the increase of beneficial bacteria Megamonas and increased the content of acetic acid, propionic acid and butyric acid, which was 2.17, 2.81, 2.43 folds that of the CON group after fermentation for 24 h, and 1.87, 2.77, 1.90 folds that of the CON group after fermentation for 48 h, respectively. This study will provide theoretical basis for the high value utilization of Dictyophora indusiata polysaccharide.