Bran Arabinoxylan Research Articles

Tailoring highland barley bran arabinoxylans: Insights into composition, structure, and functional properties

Highland barley bran (HBB) stands as an underutilized source of arabinoxylans (AXs), presenting promising prospects for various applications. This study focuses on the isolation of four different AXs (S20, S40, S60, S80) from HBB using alkali extraction and gradient alcohol precipitation. These AXs exhibited diverse purity (56.47%–80.92%), monosaccharide compositions (A/X:0.47–0.96), and molecular weights (Mw) (173.5–498.2 kDa) of different AXs, along with different microstructural variations, amorphous qualities, and thermal stability. Rheological analyses demonstrated their shear-thinning behavior and distinctive gel-forming capacities, with S20 exhibiting superior viscosity and gel-forming ability. Notably, all four AXs demonstrate notable DPPH and ABTS radical scavenging capacities, with S80 demonstrating the highest antioxidant potency. Correlation analyses highlighted connections between molecular weight, branching degree, and rheological and antioxidant properties of AXs. Among different AXs, S20, with its low branching degree (0.47) and high molecular weight (390.4 kDa), exhibited significant viscosity, suggesting its suitability as a natural thickener in food processing. Conversely, S80, characterized by its low molecular weight (173.5 kDa), high branching degree (0.96), and potent antioxidant activity, holds promise as a natural antioxidant in functional foods. This study provides crucial insights for tailoring AX applications, unlocking the potential for the valorization of HBB in diverse scenarios.

Enhanced emulsion capacity and gel properties of bighead carp myofibrillar protein through interaction with fresh maize bran arabinoxylan extracted by complex enzymes

SummaryBighead carp has the largest production amount among freshwater fish in China, but its physicochemical properties change rapidly with the denaturation of their myofibril protein (MP). The protein–polysaccharide complexes have shown interesting physicochemical properties as stabilisers and emulsifiers. In this study, arabinoxylans (AXs) were prepared and mixed with bighead carp MP to form a composite gel. The effect of AXs on the thermal stability, emulsification and emulsion stability of the composite gel was investigated. The results showed that fraction precipitated by 60% ethanol (F60) and by 90% (F90) improved the denaturation temperature of bighead carp MP from 65.99 °C to 67.39 °C and 68.22 °C, respectively. The emulsifying capacity of F60 (0.54 m2 g−1) was similar to that of sucrose (0.52 m2 g−1). The effect of F90 on the emulsion stability of bighead carp MP was better than that of F60. The elasticity of bighead carp MP was improved by F60 and F90. The hydroxyl group interactions, hydrophobic interactions and electrostatic forces exist between the macromolecules. AXs of fresh maize bran could prevent protein denaturation and improve the emulsion capacity and gel properties of bighead carp MP.

Multi-omics insights into anti-colitis benefits of the synbiotic and postbiotic derived from wheat bran arabinoxylan and Limosilactobacillus reuteri

Exploring nutritional therapies that manipulate tryptophan metabolism to activate AhR signaling represents a promising approach for mitigating chronic colitis. Arabinoxylan is a bioactive constituent abundant in wheat bran. Here, we comprehensively investigated anti-colitis potentials of wheat bran arabinoxylan (WBAX), its synbiotic and postbiotic derived from WBAX and Limosilactobacillus reuteri WX-94 (i.e., a probiotic strain exhibiting tryptophan metabolic activity). WBAX fueled L. reuteri and promoted microbial conversion of tryptophan to AhR ligands during in vitro fermentation in the culture medium and in the fecal microbiota from type 2 diabetes. The WBAX postbiotic outperformed WBAX and its synbiotic in augmenting efficacy of tryptophan in restoring DSS-disturbed serum immune markers, colonic tight junction proteins and gene profiles involved in amino acid metabolism and FoxO signaling. The WBAX postbiotic remodeled gut microbiota and superiorly enhanced AhR ligands (i.e., indole metabolites and bile acids), alongside with elevation in colonic AhR and IL-22. Associations between genera and metabolites modified by the postbiotic and colitis in human were verified and strong binding capacities between metabolites and colitis-related targets were demonstrated by molecular docking. Our study advances the novel perspective of WBAX in manipulating tryptophan metabolism and anti-colitis potentials of WBAX postbiotic via promoting gut microbiota-dependent AhR signaling.

Feruloylation and Hydrolysis of Arabinoxylan Extracted from Wheat Bran: Effect on Dough Rheology and Microstructure.

Feruloylated arabinoxylan (AX) is a potential health-promoting fiber ingredient that can enhance nutritional properties of bread but is also known to affect dough rheology. To determine the role of feruloylation and hydrolysis of wheat bran AX on dough quality and microstructure, hydrolyzed and unhydrolyzed AX fractions with low and high ferulic acid content were produced, and their chemical composition and properties were evaluated. These fractions were then incorporated into wheat dough, and farinograph measurements, large and small deformation measurements and dough microstructure were assessed. AX was found to greatly affect both fraction properties and dough quality, and this effect was modulated by hydrolysis of AX. These results demonstrated how especially unhydrolyzed fiber fractions produced stiff doughs with poor extensibility due to weak gluten network, while hydrolyzed fractions maintained a dough quality closer to control. This suggests that hydrolysis can further improve the baking properties of feruloylated wheat bran AX. However, no clear effects from AX feruloylation on dough properties or microstructure could be detected. Based on this study, feruloylation does not appear to affect dough rheology or microstructure, and feruloylated wheat bran arabinoxylan can be used as a bakery ingredient to potentially enhance the nutritional quality of bread.

Improving Biodegradable Films from Corn Bran Arabinoxylan for Hydrophobic Material and Green Food Packaging.

Non-biodegradable plastic materials pose environmental hazards and contribute to pollution. Arabinoxylan (AX) films have been created for applications in food packaging to replace these materials. The water interaction characteristics of biodegradable AX films were assessed following the extraction of AX from dry-milled corn bran (DCB), wet-milled corn bran (WCB), and dried distiller's grains with solubles (DDGS). Films were prepared with laccase and sorbitol before surface modification with lipase-vinyl acetate. Water solubility of the modified DCB films was significantly reduced (p < 0.05); however, the water solubility of modified WCB films decreased insignificantly (p > 0.05) compared to unmodified films. Water vapor permeability of the modified AX films from WCB and DDGS was significantly reduced (p < 0.05), unlike their unmodified counterparts. The biodegradation rates of the modified WCB AX and DDGS films increased after 63 and 99 days, respectively, compared to the unmodified films. The hydrophilic nature of AX polymers from WCB and DDGS enhances the biodegradability of the films. This study found that the modified WCB AX film was more hydrophobic, and the modified DDGS AX film was more biodegradable than the modified DCB AX film. Overall, surface modifications have potential for improving hydrophobicity of biopolymer films.

Adaptation to tolerate high doses of arabinoxylan is associated with fecal levels of Bifidobacterium longum

ABSTRACT Dietary fiber supplements are a strategy to close the ‘fiber gap’ and induce targeted modulations of the gut microbiota. However, higher doses of fiber supplements cause gastrointestinal (GI) symptoms that differ among individuals. What determines these inter-individual differences is insufficiently understood. Here we analyzed findings from a six-week randomized controlled trial that evaluated GI symptoms to corn bran arabinoxylan (AX; n = 15) relative to non-fermentable microcrystalline cellulose (MCC; n = 16) at efficacious supplement doses of 25 g/day (females) or 35 g/day (males) in adults with excess weight. Self-reported flatulence, bloating, and stomach aches were evaluated weekly. Bacterial taxa involved in AX fermentation were identified by bioorthogonal non-canonical amino acid tagging. Associations between GI symptoms, fecal microbiota features, and diet history were systematically investigated. AX supplementation increased symptoms during the first three weeks relative to MCC (p < 0.05, Mann-Whitney tests), but subjects ‘adapted’ with symptoms reverting to baseline levels toward the end of treatment. Symptom adaptations were individualized and correlated with the relative abundance of Bifidobacterium longum at baseline (rs = 0.74, p = 0.002), within the bacterial community that utilized AX (rs = 0.69, p = 0.006), and AX-induced shifts in acetate (rs = 0.54, p = 0.039). Lower baseline consumption of animal-based foods and higher whole grains associated with less severity and better adaptation. These findings suggest that humans do ‘adapt’ to tolerate efficacious fiber doses, and this process is linked to their microbiome and dietary factors known to interact with gut microbes, providing a basis for the development of strategies for improved tolerance of dietary fibers.

Maize bran arabinoxylans mediated green synthesis of silver nanoparticles and their incorporation in gelatin-based packaging film

Current research was aimed to extract arabinoxylans (AXs) from maize bran and synthesis of silver nanoparticles (AgNPs) through maize bran arabinoxylans (MBAXs), their characterization, and in-vitro efficacy against S. aureus, E.coli, and K. pneumoniae. Then, AgNPs were loaded in gelatin-based biofilm in different concentrations (0 %, 0.5 %, 1 %, and 1.5 %). The results showed that MBAXs contained arabinose (25.83 %), and xylose (32.12 %) in higher proportions. XRD spectra of MBAXs were amorphous, however, AgNPs capped with MBAXs showed crystalline spectra. SEM micrographs showed the spherical and irregular structure of AgNPs. Further, AgNPs showed an inhibition zone in the range of 7.38–13.78 mm, 11.45–19.14 mm, and 7.00–14.66 mm against E. coli, S. aureus, and K. pneumoniae respectively. FTIR spectra of biofilm showed stretchings at 3270, 2935, 1625, 1542, and 1030 cm−1 which showed the presence of –OH, -CH, and N-H groups of gelatin. An increase in AgNPs concentration, imparted minor changes in SEM micrographs on the film surface. Further, gelatin biofilm showed that the addition of AgNPs didn’t affect the thickness of biofilms but affected the mechanical properties after exceeding 0.5 %. The antimicrobial activity of the biofilm assessed on different foodborne pathogens showed a definite inhibition zone, which showed that packaging films loaded with AgNPs are effective in enhancing the shelf life of food commodities from microbial spoilage. Conclusively, current research showed that MBAXs are suitable for synthesizing AgNPs with definite antimicrobial activity and their incorporation in gelatin biofilm in a concentration-dependent manner could be a sustainable way to the development of sustainable packaging.

Wheat bran arabinoxylans: Chemical structure, extraction, properties, health benefits, and uses in foods.

Wheat bran (WB) is a well-known and valuable source of dietary fiber. Arabinoxylan (AX) is the primary hemicellulose in WB and can be isolated and used as a functional component in various food products. Typically, AX is extracted from the whole WB using different processes after mechanical treatments. However, WB is composed of different layers, namely, the aleurone layer, pericarp, testa, and hyaline layer. The distribution, structure, and extractability of AX vary within these layers. Modern fractionation technologies, such as debranning and electrostatic separation, can separate the different layers of WB, making it possible to extract AX from each layer separately. Therefore, AX in WB shows potential for broader applications if it can be extracted from the different layers separately. In this review, the distribution and chemical structures of AX in WB layers are first discussed followed by extraction, physicochemical properties, and health benefits of isolated AX from WB. Additionally, the utilization of AX isolated from WB in foods, including cereal foods, packaging film, and the delivery of food ingredients, is reviewed. Future perspectives on challenges and opportunities in the research field of AX isolated from WB are highlighted.

Enhancing Mechanical Properties of Corn Bran Arabinoxylan Films for Sustainable Food Packaging.

Arabinoxylan (AX)-based films can improve the mechanical characteristics of biodegradable materials when utilized for food packaging. However, the mechanical properties of AX films for food packaging applications require thorough investigation to establish their viability. In this study, AX was extracted from corn bran coproducts of dry-milling (DCB), wet-milling (WCB), and dried distiller's grains with solubles (DDGS) using an acid-alkali method. Packaging materials were produced using these AX extracts, each combined with laccase and sorbitol, forming the basis for three different films. These films were then modified by immersing the surface in a lipase-acetate solution. We evaluated their mechanical characteristics, including thickness, tensile properties, tear resistance, and puncture resistance. The thickness and tensile properties of the modified AX films derived from DCB and DDGS showed significant improvements (p < 0.05) compared to the unmodified AX films. In contrast, the modified AX films from WCB showed no significant changes (p > 0.05) in thickness and tensile properties compared to the unmodified WCB AX films. A significant increase in tear resistance (p < 0.05) was observed in all modified AX films after immersion in the lipase-acetate mixture. While puncture resistance was enhanced in the modified AX films, the improvement was not statistically significant (p > 0.05) compared to the unmodified films. The presence of hydroxyl (OH) and carbonyl (CO) groups on the surfaces of AX films from DCB and DDGS, modified by the lipase-acetate solution, suggests excellent biodegradability properties. The modification process positively affected the AX films, rendering them more bendable, flexible, and resistant to deformation when stretched, compared to the unmodified AX films.

Feruloylation and hydrolysis of arabinoxylan extracted from wheat bran: Effect on bread quality and shelf-life

Arabinoxylan (AX) is a potential health-promoting fiber ingredient that could be used to improve nutritional properties of bread, but is also known to affect bread and dough quality. To identify the role of feruloylation and hydrolysis of wheat bran AX on bread quality and shelf-life, hydrolyzed and unhydrolyzed AX with low and high ferulic acid content were incorporated into wheat bread. Water absorption, visual appearance, specific volume, and crumb structure were evaluated in fresh bread, and texture and moisture content over 14 days of storage. Feruloylated and unhydrolyzed AX breads underwent less moisture loss during storage but none of the AX fractions retarded crumb hardening. Feruloylated and hydrolyzed AX breads were comparable to control bread even at the highest addition level (5%) in terms of volume and crumb structure. The higher quality of these breads was associated with ferulic acid content and lower molar mass based on multivariate analysis. Based on our work, knowledge on specific AX structure can facilitate the use of increased AX levels in breadmaking.

When simplicity triumphs: niche specialization of gut bacteria exists even for simple fiber structures.

Structurally complex corn bran arabinoxylan (CAX) was used as a model glycan to investigate gut bacteria growth and competition on different AX-based fine structures. Nine hydrolyzate segments of the CAX polymer varying in chemical structure (sugars and linkages), CAX, five less complex non-corn arabinoxylans, and xylose and glucose were ranked from structurally complex to simple. The substrate panel promoted different overall growth and rates of growth of eight Bacteroides xylan-degrading strains. For example, Bacteroides cellulosilyticus DSM 14838 (Bacteroides cellulosilyticus) grew well on an array of complex and simple structures, while Bacteroides ovatus 3-1-23 grew well only on the simple structures. In a competition experiment, B. cellulosilyticus growth was favored over B. ovatus on the complex AX-based structure. On the other hand, on the simple structure, B. ovatus strongly outcompeted B. cellulosilyticus, which was eliminated from the competitive environment by Day 11. This adaptation to fine structure and resulting competition dynamics indicate that dietary fiber chemical structures, whether complex or simple, favor certain gut bacteria. Overall, this work supports a concept that fiber degraders diversify their competitive abilities to access substrates across the spectrum of heterogeneity of fine structural features of dietary fibers.

Development of sorghum arabinoxylan-soy protein isolate composite nanoparticles for delivery of curcumin: Effect of polysaccharide content on stability and in vitro digestibility

The purpose of this study was to fabricate composite nanoparticles using soy protein isolate (SPI) and sorghum bran arabinoxylan (AX) for the delivery of curcumin (Cur). The influences of AX concentrations on the physicochemical characteristic, stability and bioaccessibility of curcumin were investigated. The findings showed that the encapsulation efficiency of curcumin obviously increased upon incorporating AX in comparison to SPI-Cur particles. Hydrogen bonds and hydrophobic interactions were the primary driving forces for the formation of SPI-Cur-AX nanoparticles (SCA). SCA nanoparticles with 1.00 % AX exhibited a uniform size with orderly distribution, suggesting its remarkable physical stability due to the strengthened electrostatic repulsion. However, excessive AX led to aggregation of particles, a noticeable increase in size, and subsequently, a reduction in stability. Due to the heightened free radical scavenging capacity of sorghum AX, SCA nanoparticles exhibited superior antioxidant capabilities. Compared to free curcumin, encapsulation within composite particles significantly enhanced the retention rate and bioaccessibility of curcumin. This improvement was attributed to the potent emulsification ability of AX, which coordinated with bile salt to promote the transfer of curcumin into micelles. The research provides an effective strategy for developing food-grade delivery carriers aimed at enhancing dispersibility, stability and bioaccessibility of the fat-soluble bioactives.

Rice Bran Arabinoxylan Compound and Quality of Life (RBAC-QoL) of Cancer Patients: An Interim Analysis of the RBAC-QoL Study.

Background The effect of rice bran arabinoxylan compound (RBAC), a plant-based immunomodulator, on the quality of life (QoL) in cancer patients and underlying physiological pathways remains unclear. Trial design The RBAC-QoL study, a double-blind, randomised, controlled pilot feasibility study, aimed to determine RBAC's effects on QoL and the associated action mechanisms. Primary outcomes were the EORTC QLQ-C30 functional, symptom, and global QoL scores with inflammatory, nutritional, and cytokine parameters as secondary and exploratory outcomes. Methods Participants were adults diagnosed with solid organ tumours (≥ stage II) undergoing active treatment in several outpatient centres in New South Wales, Australia. Interventions were RBAC or matched placebo at 3g/day for 24 weeks allocated through stratified randomisation with participants, oncologists, and data collectors blinded. Data was collected from five study visits six weeks apart. The trial remained ongoing as of December 2023. An interim intention-to-treat analysis was performed using repeated measure ANOVA with pairwise comparisons where statistical significance was observed and adjusted with covariates. Results Global QoL scores from currently available data (n = 16; RBAC = 7, placebo = 9) were statistically different between groups (F1,8= 8.6, p = 0.019, eta2[g] = 0.267). Pairwise comparisons found significant differences at Week 6 (p = 0.032, Cohen's d = 1.454) and marginally at Week 12 (p = 0.069, d = 1.427). Age-adjusted analysis showed a continuous upward trend in QoL improvement over time with RBAC, while the placebo group did not deviate from baseline QoL. Significant elevations of serum white blood cell count (Week 18) and total protein (Weeks 12 and 18) were detected in the RBAC group compared to placebo. The total protein levels correlated highly with white blood cell count (Pearson's r = 0.539, p < 0.001) and moderately with the global QoL scores (r = 0.338, p = 0.01). No intervention-related adverse events were reported in both groups. Conclusions RBAC improves QoL beyond placebo during active cancer treatment, possibly through the immuno-nutritional pathway - these findings, though preliminary, are valuable for future research. Funding and registration: Daiwa Pharmaceutical Co., Ltd, Japan; BioMedica Nutraceuticals Pty Ltd., Australia. ANZCTR Reg No: ACTRN12619000562178p.

Arabinoxylan hydrolysates improved physical and oxidative stability of oil-in-water emulsions

This study was to improve the physical and oxidative stability of sodium caseinate (NaCas)-stabilized oil-in-water (O/W) emulsions with arabinoxylan hydrolysates (AXHs). AXHs with different molecular sizes were prepared using xylanase treatment for 0 (AXH0), 30 (AXH30), 60 (AXH60), and 120 (AXH120) min, respectively. Compared with the emulsion without AXHs, all AXHs emulsions showed increased coalescence stability, evidenced by no change occurred in the droplet size with the pH variation from 7.0 to 5.0. Moreover, at pH 7.0 and 5.0, AXH60 and AXH120 emulsions showed no flocculation, coalescence, or creaming before and after 21 d storage. All the AXH samples showed excellent antioxidant capacities, demonstrated by the slow accumulation of lipid hydroperoxides and thiobarbituric acid reactive substances during storage. In sum, rice bran arabinoxylans hydrolyzed ≥60 min possess a potential as effective antioxidants to form physically and oxidatively stable O/W emulsions at pH above the emulsifier pI, and substances with high antioxidant activity below the emulsifier pI still need to be explored.

Modified Rice Bran Arabinoxylan by Lentinus edodes Mycelial Enzyme as an Immunoceutical for Health and Aging-A Comprehensive Literature Review.

Rice bran arabinoxylan compound (RBAC) is derived from defatted rice bran enzymatically treated with Lentinus edodes mycelium. This review explores biologically active compounds and mechanisms of action that support RBAC as an immunomodulating nutraceutical in generally healthy and/or aging individuals. Thirty-seven (n = 37) primary research articles fulfilled the selection criteria for review. Most research is based on Biobran MGN-3, which consists of complex heteropolysaccharides with arabinoxylan as its primary structure while also containing galactan and glucan. RBAC was found to invoke immunological activities through direct absorption via the digestive tract and interaction with immune cells at the Peyer's patches. RBAC was shown to promote innate defence by upregulating macrophage phagocytosis and enhancing natural killer cell activity while lowering oxidative stress. Through induction of dendritic cell maturation, RBAC also augments adaptive immunity by promoting T and B lymphocyte proliferation. RBAC acts as an immunomodulator by inhibiting mast cell degranulation during allergic reactions, attenuating inflammation, and downregulating angiogenesis by modulating cytokines and growth factors. RBAC has been shown to be a safe and effective nutraceutical for improving immune health, notably in aging individuals with reduced immune function. Human clinical trials with geriatric participants have demonstrated RBAC to have prophylactic benefits against viral infection and may improve their quality of life. Further research should explore RBAC's bioavailability, pharmacodynamics, and pharmacokinetics of the complex heteropolysaccharides within. Translational research to assess RBAC as a nutraceutical for the aging population is still required, particularly in human studies with larger sample sizes and cohort studies with long follow-up periods.

Wheat bran arabinoxylan-soybean protein isolate emulsion-filled gels as a β-carotene delivery carrier: Effect of polysaccharide content on textural and rheological properties

This study aimed to investigate the effects of different wheat bran arabinoxylan (WBAX) concentrations (1, 2, 3, and 4 wt%) on the structural and physicochemical properties of WBAX-soybean protein isolate (SPI) emulsion-filled gels (EFGs) prepared using laccase and heat treatment. The properties of the various gels as well as their microstructure, rheology, and in vitro digestion behaviors were investigated. Results showed that WBAX-SPI EFGs with a 3 wt% WBAX concentration had a smooth and uniform appearance, high water holding capacity (98.5 ± 0.2 %), and enhanced mechanical properties. Rheological experiments suggested that a stronger and closer gel network was formed at 3 wt% WBAX concentration. Fourier transform infrared spectroscopy showed that laccase and heat treatment not only catalyzed the intramolecular crosslinking of WBAX and SPI, respectively, but also promoted the interaction between WBAX and SPI. Confocal laser scanning microscopy revealed that the WBAX gel network was interspersed within the SPI network. The interactions contributing to the gelation analysis revealed that chemical (disulfide bond) and physical (hydrogen bond and hydrophobic) interactions promoted the formation of denser EFGs. Furthermore, the WBAX-SPI EFGs provided a β-carotene bioaccessibility of 21.8 ± 0.6 %. Therefore, our study suggests that WBAX-SPI EFGs hold promising potential for industrial applications in the delivery of β-carotene.

Is there any hepatic impact associated with rice bran arabinoxylan compound supplementation? A systematic review and dose–response meta-analysis of randomized controlled trials

Rice Bran Arabinoxylan Compound (RBAC) results from an enzymatic modification of rice bran, which is reported to have immunomodulatory, anti-oxidant, and anti-inflammatory effects by regulating the production of pro-inflammatory cytokines. The current systematic review and meta-analysis aimed to determine the hepatic adverse effects of RBAC by assessing the effect through liver enzymes alanine aminotransferase (ALT) and aspartate aminotransferase (AST). In the present study, the Medline (PubMed), Web of Sciences, and Scopus databases were searched for relevant publications from the beginning to October 2022. The meta-analysis was based on the Mixed effect model to generate the mean effect sizes in weighted mean differences (WMD) and the 95% confidence intervals (95%CI). The heterogeneity was assessed using the Cochrane Chi-squared test, and the analysis of Galbraith plots was applied. Subgroup meta-analysis on five eligible randomized controlled trials (n=239) showed a significant decrease in serum AST regarding RBAC supplementation in powder form (WMD (95%CI)=-3.52 (-5.62,-1.42) U/L; P-value=0.001, I2 (%)=46.9; P heterogeneity=0.170), three months and more supplementation duration (WMD (95%CI)=-3.71 (-5.95,-1.48) U/L; P-value=0.001, I2 (%)=29.9; P heterogeneity=0.240) and studies with a good quality (WMD (95%CI)=-3.52 (-5.62,-1.42) U/L; P-value=0.001, I2 (%)=46.9; P heterogeneity=0.170). In conclusion, RBAC supplementation seems to not have any hepatic adverse effects and its supplementation as powder or for three months and more may decrease serum AST levels. However, we need further studies to confirm the results. CRD42022361002, registration time: 29/09/2022.

Changes in the Human Gut Microbiome during Dietary Supplementation with Modified Rice Bran Arabinoxylan Compound.

This study investigated the effects of a modified rice bran arabinoxylan compound (RBAC) as a dietary supplement on the gut microbiota of healthy adults. Ten volunteers supplemented their diet with 1 g of RBAC for six weeks and 3 g of RBAC for another six weeks, with a three-week washout period. Faecal samples were collected every 3 weeks over 21 weeks. Microbiota from faecal samples were profiled using 16S rRNA sequencing. Assessment of alpha and beta microbiota diversity was performed using the QIIME2 platform. The results revealed that alpha and beta diversity were not associated with the experimental phase, interventional period, RBAC dosage, or time. However, the statistical significance of the participant was detected in alpha (p < 0.002) and beta (weighted unifrac, p = 0.001) diversity. Explanatory factors, including diet and lifestyle, were significantly associated with alpha (p < 0.05) and beta (p < 0.01) diversity. The individual beta diversity of six participants significantly changed (p < 0.05) during the interventional period. Seven participants showed statistically significant taxonomic changes (ANCOM W ≥ 5). These results classified four participants as responders to RBAC supplementation, with a further two participants as likely responders. In conclusion, the gut microbiome is highly individualised and modulated by RBAC as a dietary supplement, dependent on lifestyle and dietary intake.

Insights into the capability of the lignocellulolytic enzymes of Penicilliumparvum 4-14 to saccharify corn bran after alkaline hydrogen peroxide pretreatment

BackgroundCorn bran is a major agro-industrial byproduct from corn starch processing. It contains abundant arabinoxylan that can be converted into value-added chemicals via biotechnology. Corn bran arabinoxylan (CBAX) is one of the most recalcitrant xylans for enzymatic degradation due to its particular heterogeneous nature. The present study aimed to investigate the capability of the filamentous fungus Penicilliumparvum 4-14 to enzymatically saccharify CBAX and reveal the fungal carbohydrate-active enzyme (CAZyme) repertoire by genome sequencing and secretome analysis.ResultsCBAX1 and CBAX2 with different branching degrees, together with corn bran residue (CBR) were generated from corn bran after alkaline hydrogen peroxide (AHP) pretreatment and graded ethanol precipitation. The protein blends E_CBAX1, E_CBAX2, and E_CBR were produced by the fungus grown on CBAX1, CBAX2, or CBR, respectively. Under the optimal conditions, E_CBAX1 released more than 80% xylose and arabinose from CBAX1 and CBAX2. Almost complete saccharification of the arabinoxylans was achieved by combining E_CBAX1 and a commercial enzyme cocktail Cellic®CTec3. Approximately 89% glucose, 64% xylose, and 64% arabinose were liberated from CBR by E_CBR. The combination of E_CBR with Cellic®CTec3 enhanced the saccharification of CBR, with conversion ratios of 97% for glucose, 81% for xylose, and 76% for arabinose. A total of 376 CAZymes including plentiful lignocellulolytic enzymes were predicted in P.parvum based on the fungal genomic sequence (25.8 Mb). Proteomic analysis indicated that the expression of CAZymes in P.parvum varied between CBAX1 and CBR, and the fungus produced complete cellulases, numerous hemicellulases, as well as high levels of glycosidases under the culture conditions.ConclusionsThis investigation disclosed the CAZyme repertoire of P.parvum at the genomic and proteomic levels, and elaborated on the promising potential of fungal lignocellulolytic enzymes upon saccharification of corn bran biomass after AHP pretreatment.

Fine structural features and antioxidant capacity of ferulated arabinoxylans extracted from nixtamalized maize bran.

The nixtamalization process improves the nutritional and technological properties of maize. This process generates nixtamalized maize bran as a by-product, which is a source of arabinoxylans (AX). AX are polysaccharides constituted of a xylose backbone with mono- or di-arabinose substitutions, which can be ester-linked to ferulic acid (FA). The present study investigated the fine structural features and antioxidant capacity (AC) of nixtamalized maize bran arabinoxylans (MBAX) to comprehend the structure-radical scavenging capacity relationship in this polysaccharide deeply. MBAX presented a molecular weight, intrinsic viscosity, and hydrodynamic radius of 674 kDa, 1.8 dL g-1 , and 24.6 nm, respectively. The arabinose-to-xylose ratio (A/X) and FA content were 0.74 and 0.25 g kg-1 polysaccharide, respectively. MBAX contained dimers (di-FA) and trimer (tri-FA) of FA (0.14 and 0.07 g kg-1 polysaccharide, respectively). The main di-FA isomer was the 8-5' structure (80%). Fourier transform infrared spectroscopy confirmed MBAX molecular identity, and the second derivate of the spectral data revealed a band at 958 cm-1 related to the presence of arabinose disubstitution. 1 H-Nuclear magnetic resonance spectroscopy showed mono- and di-arabinose substitution in the xylan backbone with more monosubstituted residues. MBAX registered an AC of 25 and 20 μmol Trolox equivalents g-1 polysaccharide despite a low FA content, using ABTS (2,2'-azino-bis-3-ethylbenzthiazoline-6-sulfonic acid) and DPPH (1,1-diphenyl-2-picrylhydrazyl) methods, respectively. AC in MBAX could be related to the high A/X ratio (mainly monosubstitution) and the high 8-5' di-FA proportion in this polysaccharide. © 2023 Society of Chemical Industry.