Extraction and modification technology of arabinoxylans from cereal by-products: A critical review

Valorization of barley (Hordeum vulgare L.) brans from the sustainable perspective: A comprehensive review of bioactive compounds and health benefits with emphasis on their potential applications

Barley is an important source of sustainable diets for humans, while its brans is commonly disposed as wastes. The recycling of barley brans has become a key for facilitating the valorization of barley as a whole to achieve its sustainable development. This review summarized the value of barley brans as an excellent source of multiple functional components (phenolic compounds, β-glucan, and arabinoxylan), which conferred extensive health benefits to barley brans mainly including antioxidant, anti-obesity and lipid-lowering, anti-diabetic, and hepatoprotective properties. The utilization of barley brans reflected a great potential for sustainable development. Exploiting of food products and edible films containing barley brans or their bioactive compounds and non-food applications (preparation of bioactive substances, laccase enzymes, and biosorbents) have been attempted for supporting the zero-waste concept and circular economy. Considering their diverse applications, effective extraction techniques of bioactive compounds from barley brans and their safety are the priority of future research.

Cereal-Derived Water-Unextractable Arabinoxylans: Structure Feature, Effects on Baking Products and Human Health

Arabinoxylans (AXs) are non-starch polysaccharides with complex structures naturally occurring in grains (i.e., barley, corn, and others), providing many health benefits, especially as prebiotics. AXs can be classified as water-extractable (WEAX) and water-unextractable (WUAX) based on their solubility, with properties influenced by grain sources and extraction methods. Numerous studies show that AXs exert an important health impact, including glucose and lipid metabolism regulation and immune system enhancement, which is induced by the interactions between AXs and the gut microbiota. Recent research underscores the dependence of AX physiological effects on structure, advocating for a deeper understanding of structure-activity relationships. While systematic studies on WEAX are prevalent, knowledge gaps persist regarding WUAX, despite its higher grain abundance. Thus, this review reports recent data on WUAX structural properties (chemical structure, branching, and MW) in cereals under different treatments. It discusses WUAX applications in baking and the benefits deriving from gut fermentation.

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.

A water-soluble arabinoxylan from Chinese liquor distillers' grains: Structural characterization and anti-colitic properties

Chinese liquor distillers' grain (CLDG) is a valuable and abundant by-product from traditional Chinese baijiu production, containing a diverse array of bioactive components that have attracted significant interest. Herein, a water-soluble polysaccharide, DGPS-2B, with a weight-average molecular weight of 37.3 kDa, was isolated from the alkali-extract fraction of CLDG. Methylation and NMR analysis identified that the primary constituents of DGPS-2B are arabinoxylans, with an arabinose-to-xylose ratio of 0.66. In an animal model of colitis, DGPS-2B treatment significantly altered the gut microbiota composition by increasing the SCFA-producing bacteria (e.g., Butyricicoccus) and reducing the mucin-degrading bacteria such as Muribaculaceae. This microbial shift resulted in elevated production of butyrate, acetate, and propionate, which subsequently suppressed NF-κB signaling, decreased the levels of IL-1β, IL-6, and TNFα, and potentially inactivated Notch signaling. These multifaceted effects stimulated mucin 2 production, reduced inflammation and apoptosis in the gut epithelium, and ultimately alleviated colitis symptoms. Collectively, this study not only elucidates the purification and characterization of DGPS-2B from CLDG but also illuminates its anti-colitic properties and the underlying molecular mechanisms. These findings underscore the potential of DGPS-2B as a therapeutic intervention for managing inflammatory bowel disease and emphasize CLDG as a promising source for developing value-added products.

Evaluating the application of an arabinoxylan-rich fraction from brewers' spent grain as a release modifier of drugs

This study evaluated the possible use of a fraction of brewers' spent grain rich in arabinoxylans (BSG-AX) as an excipient that modifies the release of class III drugs (Biopharmaceutics Classification System), by determining the release profile of metformin hydrochloride (MH), in a water medium. The cumulative percentage of MH release showed the best linear fit when modeled with the cumulative distribution function (CDF) of the Weibull distribution (R2 = 0.993 ± 0.001). According to the Korsmeyer-Peppas model, the first stage of MH release is regulated by a super case-II transport mechanism controlled by the expansion and relaxation of BSG-AX. Finally, with the Hixson-Crowell model, a release rate (k HC ) of 0.350 ± 0.026 h - 1 3 was obtained (R2 = 0.996 ± 0.007). BSG-AX constitutes a suitable material for producing prolonged drug release vehicles; however, additional research is required to provide a better encapsulation of the active ingredients to ensure their optimal applicability and performance.

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.

Arabinoxylans matrixes as a potential material for drug delivery systems development - A bibliometric analysis and literature review

Arabinoxylans (AX) have become a focal point in the pharmaceutical sector owing to their physicochemical, biological, and functional properties. The purpose of this paper was to present a summary of the utilization of AX as drug release matrices through a bibliometric analysis (BA) and a literature review to spotlight the AX functional characteristics and their technological applications to promote this line of research. The BA was carried out using data from a Web of Science database research, specifically emphasizing the analysis of authors' keywords. This approach was chosen due to its significance in comprehensively understanding a particular research field and its relevance for in-depth knowledge of a research field. The BA outcomes revealed limited information concerning the AX applications in both release matrices and as excipients in the formulation and development of drug delivery systems (DDS), so there is a need for additional scientific and technological research in these areas to address the existing information gaps. However, the literature review shows that the native and modified AX from different delivery release systems, such as macrogels (including films, tablets, and hard gelatin capsules) and multi-particulate systems (including micro and nanogels), present an excellent potential as release matrices of biomolecules and drugs, such as doxorubicin, diclofenac sodium, caffeine, gentamicin, tizanidine hydrochloride, and insulin. In conclusion, AX have a wide potential for application in the pharmaceutical industry, so this work is expected to be a reference point for future research by scientists, technologists, and entrepreneurs who cope with the subject.

Valorization of Spent Grains from Beer Production through β-Glucan Extraction

Brewers' spent grains (BSG) are the major byproduct of the brewing industry. Recently, it has been found that β-glucan, which can be used as a food supplement, can be extracted from BSG and offers the greatest added value. This study aimed to investigate the effects of temperature (45-90 °C) and time (30-120 min) on β-glucan extraction efficiency when using hot water extraction. β-glucan was precipitated upon 80% ethanol addition. The chemical compositions were examined. The highest β-glucan concentration and yield were obtained at a temperature and time of 60 °C and 90 min, respectively. The functional properties of the extracted β-glucan were analyzed and compared with other commercial stabilizers such as sodium carboxymethyl cellulose (CMC), xanthan gum, gum arabic, and oat β-glucan. All stabilizers exhibited non-Newtonian flow behavior, except for gum arabic, which exhibited Newtonian flow behavior. The water holding capacity of BSG β-glucan was 6.82 g/g and the creaming index of the emulsions stabilized with BSG β-glucan was 89.05%. BSG β-glucan improved the color and stability of orange juice by reducing the precipitation of orange pulp. This study illustrated that BSG β-glucan can be used as a stabilizer and viscosity enhancer in foods, depending on the concentration, which can be applied to a variety of foods.

Structural and emulsion-stabilizing properties of the alkali-extracted arabinoxylans from corn and wheat brans

This study investigated the structural and emulsion-stabilizing capacities of alkali-extracted arabinoxylans from corn and wheat bran (CAXs and WAXs). The results demonstrated that all AXs were mainly composed of arabinose and xylose. WAXs had a higher weight-average molecular weight (Mw, 375-473 KDa) and protein content (3.09-8.68 %) but lower total phenolic acid content (TPC, 1.18-1.91 mg gallic acid equivalents/g) than CAXs; however, CAX stabilized emulsions exhibited smaller and more regular oil droplet size (524-589 nm) and higher absolute value of ζ potential (48-52 mV) compared with WAX stabilized emulsions during storage. Moreover, the increment of NaOH concentration caused a decrease in Mw, protein content, and TPC of CAXs or WAXs and the corresponding CAXs or WAXs emulsions showed bigger and more unstable oil droplets during 14 d storage. The Mw, protein, and TPC were well correlated with their emulsion stability. Furthermore, emulsions stabilized by AXs with low-concentration NaOH could resist better various temperatures, pH, and NaCl. In conclusion, the structural properties of AXs derived from different cereal sources and treated with different concentrations of NaOH varied, leading to differences in their ability to stabilize emulsions. CAXs or WAXs obtained from low-concentration NaOH treatment demonstrated significant potential as highly effective natural emulsifiers.

Impact of Six Extraction Methods on Molecular Composition and Antioxidant Activity of Polysaccharides from Young Hulless Barley Leaves

Young hulless barley leaves are gaining recognition for potential health benefits, and the method of extracting polysaccharides from them is critical for potential food industry applications. This study delves into a comparative analysis of six distinct fiber extraction techniques: hot water extraction; high-pressure steam extraction; alkaline extraction; xylanase extraction; cellulase extraction; and combined xylanase and cellulase extraction. This analysis included a thorough comparison of polysaccharide-monosaccharide composition, structural properties, antioxidant activities (DPPH, ABTS, and FRAP), and rheological properties among fibers extracted using these methods. The results underscore that the combined enzymatic extraction method yielded the highest extraction yield (22.63%), while the rest of the methods yielded reasonable yields (~20%), except for hot water extraction (4.11%). Monosaccharide composition exhibited divergence across methods; alkaline extraction yielded a high abundance of xylose residues, whereas the three enzymatic methods demonstrated elevated galactose components. The extracted crude polysaccharides exhibited relatively low molecular weights, ranging from 5.919 × 104 Da to 3.773 × 105 Da across different extraction methods. Regarding antioxidant activities, alkaline extraction yielded the highest value in the ABTS assay, whereas enzymatically extracted polysaccharides, despite higher yield, demonstrated lower antioxidant capacity. In addition, enzymatically extracted polysaccharides exerted stronger shear thinning behavior and higher initial viscosity.

Sugarcane Straw as a Source of Arabinoxylans: Optimization and Economic Viability of a Two-Step Alkaline Extraction

Sugarcane processing produces a significant amount of byproducts in the form of straw and bagasse, which are rich in cellulose, hemicellulose, and lignin. This work aims to provide a valorization approach to sugarcane straw by optimizing a two-step alkaline extraction of arabinoxylans by a response surface methodology to evaluate a potential industrial-scale production. Sugarcane straws were delignified using an alkaline-sulfite pretreatment, followed by alkaline extraction and precipitation of arabinoxylan, a two-step process optimized using a response surface methodology. A KOH concentration of (2.93-17.1%) and temperature (18.8-61.2 °C) were chosen as independent variables, and the arabinoxylan yield (%) as a response variable. The model application shows that KOH concentration, temperature, and the interaction between both independent variables are significant in extracting arabinoxylans from straw. The best-performing condition was further characterized by FTIR, DSC, and chemical and molecular weight evaluation. The straws arabinoxylans presented high purities levels, ca. 69.93%, and an average molecular weight of 231 kDa. The overall estimated production cost of arabinoxylan from straw was 0.239 €/g arabinoxylan. This work demonstrates a two-step alkaline extraction of the arabinoxylans method, as well as their chemical characterization and economic viability analysis, that can be used as a model for industrial scale-up production.

The addition of crosslinked corn bran arabinoxylans with different gelling characteristics was associated with the pasting, rheological, structural, and digestion properties of corn starch

Crosslinked corn bran arabinoxylan (CLAX) is a food hydrocolloid that can be applied to improve the physicochemical and digestion properties of starch. However, the impact of CLAX with different gelling characteristics on starch properties remains elusive. Here, high cross-linked arabinoxylan (H-CLAX), moderate crosslinked arabinoxylan (M-CLAX), and low crosslinked arabinoxylan (L-CLAX) were fabricated to investigate their effects on the pasting, rheological, structural, and in vitro digestion property of corn starch (CS). The results showed that H-CLAX, M-CLAX, and L-CLAX differently increased the pasting viscosity and gel elasticity of CS, with H-CLAX exhibiting the greatest effect. The structural characterization of CS-CLAX mixtures showed that H-CLAX, M-CLAX, and L-CLAX differently enhanced the swelling power of CS and increased the hydrogen bonds between CS and CLAX. Furthermore, the addition of CLAX (especially H-CLAX) significantly reduced both the digestion rate and extent of CS, probably due to the increased viscosity and the formation of the amylose-polyphenol complex. This study provided new insights into the interaction between CS and CLAX, and could help to develop healthier foods with slow starch digestibility.

Extraction and characterization of cereal bran cell wall in relation to its end use perspectives

The main objective of the current research was to explore the physicochemical, microbial and sensorial attributes of cereals bran cell wall (CBCW) enriched bread. In 1st phase, the cell wall wasextracted from different cerealsbran and characterized for its dietary fiber profile and antioxidant activity. In addition, bread was prepared with the additionof CBCW at different ratios and explored for physicochemical, microbialand sensorial characteristics. Current results showed that total dietary fiber contents of CBCW were 59.1 ± 0.2%, 61.2 ± 0.03% and 68.8 ± 0.2% in wheat, maize and oat bran respectively. Furthermore, maize bran cell wall showed higher antioxidant activityof ferric reducing antioxidant power (FRAP), DPPH and ABTS were 52.5 ± 0.12, 28.4 ± 0.07 and 18 ± 0.05 µmol TE/g as compared to wheat and oat bran cell wall. Additionally, CBCWimproved the bread quality in terms of physicochemical, microbial and sensorial characteristics.Moreover, CBCW-enriched bread showed higher loaf volume, loaf height, the specific volume of loaf and weight of bread as compared to control due to less baking loss. Furthermore, maize bran cell wall enriched bread exhibited less growth after 4 days as compared to other treatments. Moreover, CBCW-enriched bread showed higher sensorial properties score than C0.Convulsively, CBCW-enriched bread has good physicochemical, microbial and sensorial properties as compared to control bread.

Hydration of Wheat Flour Water-Unextractable Cell Wall Material Enables Structural Analysis of Its Arabinoxylan by High-Resolution Solid-State 13C MAS NMR Spectroscopy

To enable its structural characterization by nuclear magnetic resonance (NMR) spectroscopy, the native structure of cereal water-unextractable arabinoxylan (WU-AX) is typically disrupted by alkali or enzymatic treatments. Here, WU-AX in the wheat flour unextractable cell wall material (UCWM) containing 40.9% ± 1.5 arabinoxylan with an arabinose-to-xylose ratio of 0.62 ± 0.04 was characterized by high-resolution solid-state NMR without disrupting its native structure. Hydration of the UCWM (1.7 mg H₂O/mg UCWM) in combination with specific optimizations in the NMR methodology enabled analysis by solid-state ¹³C NMR with magic angle spinning and ¹H high-power decoupling (¹³C HPDEC MAS NMR) which provided sufficiently high resolution to allow for carbon atom assignments. Spectral resonances of C-1 from arabinose and xylose residues of WU-AX were here assigned to the solid state. The proportions of un-, mono-, and di-substituted xyloses were 59.2, 19.5, and 21.2%, respectively. ¹³C HPDEC MAS NMR showed the presence of solid-state fractions with different mobilities in the UCWM. This study presents the first solid-state NMR spectrum of wheat WU-AX with sufficient resolution to enable assignment without prior WU-AX solubilization.

Effect of physicochemical properties, pre-processing, and extraction on the functionality of wheat bran arabinoxylans in breadmaking - A review

Arabinoxylan (AX) is an abundant hemicellulose in wheat bran and an important functional component in bakery products. This review compares preprocessing and extraction methods, and evaluates their effect on AX properties and functionality as a bread ingredient. The extraction process results in AX isolates or concentrates with varying molecular characteristics, indicating that the process can be adjusted to produce AX with targeted functionality. AX functionality in bread seems to depend on AX properties but also on AX addition level and interactions with other components. This review suggests that the use of AX with tailored properties together with properly optimized baking process could help increasing the amount of added fiber in bread while maintaining or even improving bread quality.

Valorization of Wheat Bran by Three Fungi Solid-State Fermentation: Physicochemical Properties, Antioxidant Activity and Flavor Characteristics

Three medicinal fungi were used to carry out solid-state fermentation (SSF) of wheat bran. The results showed that the use of these fungi for SSF significantly improved wheat bran’s nutritional properties including the extraction yield of soluble dietary fiber (SDF), total phenolic content (TPC), total flavonoid content (TFC), physical properties containing swelling capacity (SC) and oil absorption capacity (OAC), as well as antioxidant activities. Electronic nose and GC–MS analyses showed that fermented wheat bran had different volatiles profiles compared to unfermented wheat bran. The results suggest that SSF by medicinal fungi is a promising way for the high-value utilization of wheat bran.

Arabinoxylans Release from Brewers’ Spent Grain Using Extrusion and Solid-State Fermentation with Fusarium oxysporum and the Antioxidant Capacity of the Extracts

Brewers’ spent grain (BSG) is the most abundant byproduct generated from the beer-brewing process. BSG is a material rich in hemicellulose, composed of arabinoxylans (AX). However, the high crosslinking of this material causes low availability of AX, for which it is necessary to apply different treatments. The objective of this research is to increase the release of arabinoxylans through solid-state fermentation with Fusarium oxysporum f. sp. lycopersici using extruded brewery spent grain. First, the BSG is subjected to two types of physical treatments: extrusion at 20% moisture, 200 rpm and 50 °C (BSGe), and blade milling (BSGm). The chemical composition is determined for each sample (BSG, BSGe and BSGm). Subsequently, the solid-state fermentation process (SSF) is carried out on each sample. The fermentation kinetics at 30 °C are monitored for 7 days. Once the SSF concludes, AX are extracted, and the purity of AX is determined by the phloroglucinol colorimetric assay. Finally, the total phenolic compounds, phenolic acids and antioxidant capacity by DPPH are quantified. No significant differences (p ≥ 0.05) in the protein, lipid, ash or total dietary fiber contents are found among the samples. No significant difference (p ≥ 0.05) in the content of soluble fiber is found, although BSGe and BSGm have higher values than BSG. On the other hand, the yields of soluble AX exhibit significant differences (p ≤ 0.05) among nonfermented samples (BSG, 0.03%; BSGm, 0.53%; BSGe, 0.70%) and with SSF (BSG, 2.95%; BSGm, 6.24%; and BSGe, 9.58%). In addition, the contents of free phenolic compounds and free phenolic acids and the percent inhibition of free extracts by 2,2-diphenyl-1-picrylhydrazyl (DPPH) differ significantly (p ≤ 0.05) between samples subjected to SSF and nonfermented samples. Therefore, extrusion and SSF treatment increase AX release from BSG as well as the antioxidant capacity of the extracts.

Arabinoxylans as Functional Food Ingredients: A Review

The health benefits of fibre consumption are sound, but a more compressive understanding of the individual effects of different fibres is still needed. Arabinoxylan is a complex fibre that provides a wide range of health benefits strongly regulated by its chemical structure. Arabinoxylans can be found in various grains, such as wheat, barley, or corn. This review addresses the influence of the source of origin and extraction process on arabinoxylan structure. The health benefits related to short-chain fatty acid production, microbiota regulation, antioxidant capacity, and blood glucose response control are discussed and correlated to the arabinoxylan’s structure. However, most studies do not investigate the effect of AX as a pure ingredient on food systems, but as fibres containing AXs (such as bran). Therefore, AX’s benefit for human health deserves further investigation. The relationship between arabinoxylan structure and its physicochemical influence on cereal products (pasta, cookies, cakes, bread, and beer) is also discussed. A strong correlation between arabinoxylan’s structural properties (degree of branching, solubility, and molecular mass) and its functionalities in food systems can be observed. There is a need for further studies that address the health implications behind the consumption of arabinoxylan-rich products. Indeed, the food matrix may influence the effects of arabinoxylans in the gastrointestinal tract and determine which specific arabinoxylans can be included in cereal and non-cereal-based food products without being detrimental for product quality.

Sustainable Applications for the Valorization of Cereal Processing By-Products

This review article revises the sustainable practices and applications to valorize valuable components recovered from cereal processing by-products. After introducing cereal processing by-products, their healthy compounds, and corresponding functional properties, the article explores reutilization opportunities of by-products emphasizing specific sources (e.g., oat and wheat bran, distillers' dried grains, etc.) and the biorefinery approach. Proteins and soluble dietary fibers such as arabinoxylans are of particular interest due to their content in the cereal processing by-products and their easy extraction based on conventional technologies such as enzyme-assisted extraction and membrane filtration. Non-thermal technologies have also been suggested to improve sustainability recovery approaches. Finally, the article discusses the different applications for the recovered high-added value compounds that span across biotechnology, foods, and bakery products.

Valorization of cereal by-product hemicelluloses: Fractionation and purity considerations

The biomass from cereal side streams is rich in valuable components, such as hemicelluloses. Among the hemicelluloses, arabinoxylans and β-glucans are the most acknowledged for potential health benefits. Numerous publications discuss the potential to use purified forms of these hemicelluloses for various applications. However, as the purification of hemicelluloses may not be economically feasible to upscale, sustainable and cost-effective methods are needed to make their valorization more realistic for industrial applications. Co-components present in hemicellulose-rich fractions may also provide added functionality, such as flavonoid content and antioxidant capacity. This review provides an overview on the feasibility of sustainably upscaling hemicellulose extraction processes, focusing on by-products from different cereal streams. We describe the hemicelluloses' physicochemical properties and provide various possible applications of pure and impure fractions from small scale to pilot and industrial scale. Furthermore, real case examples on the industrial utilization of cereal side streams are enclosed. This review provides pathways for future research for developing the hemicellulose extraction methods to obtain fractions with optimized purity, and offers suggestions to valorize them.

Feruloylated arabinoxylan from wheat bran inhibited M1-macrophage activation and enhanced M2-macrophage polarization

The effects of feruloylated arabinoxylan (AX) on typically activated inflammatory macrophages (M1) and alternatively anti-inflammatory macrophages (M2) and its possible mechanisms were investigated. The results revealed that feruloylated AX was composed of 37.63% arabinose and 52.23% xylose, with a weight-average molecular weight of 1.1374 × 10⁴ Da, and bound ferulic acid content of 10.84 mg/g. Besides, feruloylated AX (50-1000 μg/mL) markedly downregulated the mRNA expressions of NO, IL-1β, TNF-α, IL-6, and IL-23a, and reduced the phosphorylation levels of p38, ERK, and JNK in M1. In contrast, the mRNA expressions of Arg-1, Mrc-1, and CCL22 were significantly upregulated by feruloylated AX (50-1000 μg/mL), and the phosphorylation level of AKT was significantly increased in M2. Overall, our results indicated that feruloylated AX could have an inhibitory or a promoting effect on already activated macrophages, and MAPK or PI3K signaling pathways might be involved in this regulation.

Isolation, Structural, Functional, and Bioactive Properties of Cereal Arabinoxylan─A Critical Review

Arabinoxylans (AXs) are widely distributed in various cereal grains, such as wheat, corn, rye, barley, rice, and oat. The AX molecule contains a linear (1,4)-β-D-xylp backbone substituted by α-L-araf units and occasionally t-xylp and t-glcpA through α-(1,2) and/or α-(1,3) glycosidic linkages. Arabinoxylan shows diversified functional and bioactive properties, influenced by their molecular mass, branching degree, ferulic acid (FA) content, and the substitution position and chain length of the side chains. This Review summarizes the extraction methods for various cereal sources, compares their structural features and functional/bioactive properties, and highlights the established structure-function/bioactivity relationships, intending to explore the potential functions of AXs and their industrial applications.

Process-Induced Changes in the Quantity and Characteristics of Grain Dietary Fiber

Daily use of wholegrain foods is generally recommended due to strong epidemiological evidence of reduced risk of chronic diseases. Cereal grains, especially the bran part, have a high content of dietary fiber (DF). Cereal DF is an umbrella concept of heterogeneous polysaccharides of variable chemical composition and molecular weight, which are combined in a complex network in cereal cell walls. Cereal DF and its distinct components influence food digestion throughout the gastrointestinal tract and influence nutrient absorption and other physiological reactions. After repeated consumption of especially whole grain cereal foods, these effects manifest in well-demonstrated health benefits. As cereal DF is always consumed in the form of processed cereal food, it is important to know the effects of processing on DF to understand, safeguard and maximize these health effects. Endogenous and microbial enzymes, heat and mechanical energy during germination, fermentation, baking and extrusion destructurize the food and DF matrix and affect the quantity and properties of grain DF components: arabinoxylans (AX), beta-glucans, fructans and resistant starch (RS). Depolymerization is the most common change, leading to solubilization and loss of viscosity of DF polymers, which influences postprandial responses to food. Extensive hydrolysis may also remove oligosaccharides and change the colonic fermentability of DF. On the other hand, aggregation may also occur, leading to an increased amount of insoluble DF and the formation of RS. To understand the structure–function relationship of DF and to develop foods with targeted physiological benefits, it is important to invest in thorough characterization of DF present in processed cereal foods. Such understanding also demands collaborative work between food and nutritional sciences.

Valorization of Rice Straw into Cellulose Microfibers for the Reinforcement of Thermoplastic Corn Starch Films

In the present study, agro-food waste derived rice straw (RS) was valorized into cellulose microfibers (CMFs) using a green process of combined ultrasound and heating treatments and were thereafter used to improve the physical properties of thermoplastic starch films (TPS). Mechanical defibrillation of the fibers gave rise to CMFs with cumulative frequencies of length and diameters below 200 and 5–15 µm, respectively. The resultant CMFs were successfully incorporated at, 1, 3, and 5 wt% into TPS by melt mixing and also starch was subjected to dry heating (DH) modification to yield TPS modified by dry heating (TPSDH). The resultant materials were finally shaped into films by thermo-compression and characterized. It was observed that both DH modification and fiber incorporation at 3 and 5 wt% loadings interfered with the starch gelatinization, leading to non-gelatinized starch granules in the biopolymer matrix. Thermo-compressed films prepared with both types of starches and reinforced with 3 wt% CMFs were more rigid (percentage increases of ~215% for TPS and ~207% for the TPSDH), more resistant to break (~100% for TPS and ~60% for TPSDH), but also less extensible (~53% for TPS and ~78% for TPSDH). The incorporation of CMFs into the TPS matrix at the highest contents also promoted a decrease in water vapor (~15%) and oxygen permeabilities (~30%). Finally, all the TPS composite films showed low changes in terms of optical properties and equilibrium moisture, being less soluble in water than the TPSDH films.

Conformational Behavior, Topographical Features, and Antioxidant Activity of Partly De-Esterified Arabinoxylans

This study aimed to investigate the effect of arabinoxylans (AX) partial de-esterification with feruloyl esterase on the polysaccharide conformational behavior, topographical features, and antioxidant activity. After enzyme treatment, the ferulic acid (FA) content in AX was reduced from 7.30 to 5.48 µg FA/mg polysaccharide, and the molecule registered a small reduction in radius of gyration (RG), hydrodynamic radius (Rh), characteristic ratio (C∞), and persistence length (q). A slight decrease in α and a small increase in K constants in the Mark-Houwink-Sakurada equation for partially de-esterified AX (FAX) suggested a reduction in molecule structural rigidity and a more expanded coil conformation, respectively, in relation to AX. Fourier transform infrared spectroscopy spectra of AX and FAX presented a pattern characteristic for this polysaccharide. Atomic force microscopy topographic analysis of FAX showed a more regular surface without larger hollows in relation to AX. The antioxidant activity of FAX, compared to AX, was reduced by 30 and 41% using both 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS+) and 1,1-diphenyl-2-picryl-hydrazyl (DPPH) methods, respectively. These results suggest that feruloyl esterase treatment of AX could offer a strategy to tailor AX chains conformation, morphological features, and antioxidant activity, impacting the development of advanced biomaterials for biomedical and pharmaceutical applications.

Comparison of Alkaline/Oxidative and Hydrothermal Extraction of Wheat Bran Arabinoxylans

The bran accounts for approximately 25% of the wheat kernel but is currently only a by-product, used as animal feed. However, due to its high arabinoxylan content it could be a valuable raw material for food production. Arabinoxylans cannot be digested in the human intestine but are intensely studied for their health-beneficial properties. These include glycemic control by formation of a highly viscous gel in the intestine, and hence delaying starch digestion, alongside an increase in short chain fatty acids. To apply sufficient amounts of arabinoxylan for health-beneficial effects, extraction and concentration is required. Alkaline/oxidative conditions are commonly used, but for potential food applications more cost-efficient methods, without hazardous chemicals, are required. Therefore, this study aimed to optimize the conditions for hydrothermal extraction (extraction time and temperature) at laboratory-scale and to compare the results to an established alkaline/oxidative method. The resulting extracts were characterized for yield, purity, arabinoxylan molecular mass, arabinose/xylose ratio, and viscosity to evaluate the quality of the method. For the hydrothermal extraction, an extraction time of 1 h at 160 °C and 6.5 bar gave the best results. However, even these optimized conditions resulted in lower extract purity and severely degraded arabinoxylans. Although further optimization of the hydrothermal process is required, the present work builds an important foundation for the development of an industrial hydrothermal extraction method.

Debranching enzymes in corn/soybean meal-based poultry feeds: a review

This review discusses the complex nature of the primary nonstarch polysaccharide (NSP) in corn with respect to the merit of debranching enzymes. Celluloses, hemicelluloses, and pectins comprise the 3 major categories of NSP that make up nearly 90% of plant cell walls. Across cereals, the hemicellulose arabinoxylan exists as the primary NSP, followed by cellulose, glucans, and others. Differences in arabinoxylan structure among cereals and cereal fractions are facilitated by cereal type, degree and pattern of substitution along the xylan backbone, phenol content, and cross-linkages. In particular, arabinoxylan (also called glucuronoarabinoxylan) in corn is heavily fortified with substituents, being more populated than in wheat and other cereal grains. Feed-grade xylanases - almost solely of the glycoside hydrolase (GH) 10 and GH 11 families - require at least 2 or 3 contiguous xylose units to be free of attachments to effectively attack the xylan chain. This canopy of attachments, along with a high phenol content and the insoluble nature of corn glucuronoarabinoxylan, confers a significant resistance to xylanase attack. Both in vitro and in vivo studies demonstrate that debranching enzymes appreciably increase xylanase access and fiber degradability by removing these attachments and breaking phenolic linkages. The enzymatic degradation of the highly branched arabinoxylan can facilitate disassembly of other fibers by increasing exposure to pertinent carbohydrases. For cereals, the arabinofuranosidases, α-glucuronidases, and esterases are some of the more germane debranching enzymes. Enzyme composites beyond the simple core mixes of xylanases, cellulases, and glucanases can exploit synergistic benefits generated by this class of enzymes. A broad scope of enzymatic activity in customized mixes can more effectively target the resilient NSP construct of cereal grains in commercial poultry diets, particularly those in corn-based feeds.

Not All Fibers Are Born Equal; Variable Response to Dietary Fiber Subtypes in IBD

Diet provides a safe and attractive alternative to available treatment options in a variety of diseases; however, research has only just begun to elucidate the role of diet in chronic diseases, such as the inflammatory bowel diseases (IBD). The chronic and highly debilitating IBDs, Crohn disease and ulcerative colitis, are hallmarked by intestinal inflammation, immune dysregulation, and dysbiosis; and evidence supports a role for genetics, microbiota, and the environment, including diet, in disease pathogenesis. This is true especially in children with IBD, where diet-based treatments have shown excellent results. One interesting group of dietary factors that readily links microbiota to gut health is dietary fibers. Fibers are not digested by human cells, but rather fermented by the gut microbes within the bowel. Evidence has been mounting over the last decade in support of the importance of dietary fibers in the maintenance of gut health and in IBD; however, more recent studies highlight the complexity of this interaction and importance of understanding the role of each individual dietary fiber subtype, especially during disease. There are roughly ten subtypes of dietary fibers described to date, categorized as soluble or insoluble, with varying chemical structures, and large differences in their fermentation profiles. Many studies to date have described the benefits of the byproducts of fermentation in healthy individuals and the potential health benefits in select disease models. However, there remains a void in our understanding of how each of these individual fibers affect human health in dysbiotic settings where appropriate fermentation may not be achieved. This review highlights the possibilities for better defining the role of individual dietary fibers for use in regulating inflammation in IBD.

Optimisation of double-enzymatic extraction of arabinoxylan from fresh corn fibre

Enzymatic extraction of arabinoxylans (AXs) is an attractive and environmentally friendly extraction option, in which technical considerations (yield and purity) have been coupled with environmental concerns. Amano HC 90 and Cellulase were combined to evaluate their interactive effects on AX extraction from destarched, deproteinised bran (DSDPB). A response surface methodology was used to obtain the optimal extraction conditions. The experimental data fit well with the predicted values and the model adequately represented the actual relationship among the measured parameters. The extraction yield and AX content in the extract under optimal conditions (double-enzyme dose of 920 U/g, pH of 3.0, extraction temperature of 35.0 °C; extraction time of 6 h; and DSDPB to liquid ratio of 1:30) were 40.73 ± 0.09% and 75.88 ± 0.11%, respectively. The double-enzymatic extraction method of AX from fresh corn fibre was more efficient than the chemical method.

Preparation and characterization of pH-responsive microgel using arabinoxylan from wheat bran for BSA delivery

Wheat bran arabinoxylan (AX) discard from wheat production was utilized to form pH-responsive microgels. AX was modified by carboxymethylation, and the carboxymethylated arabinoxylans (CMAX) were characterized by FT-IR, NMR, gel permeation chromatography (GPC), and rheological analysis. The CMAX microgel was cross-linked by Fe³⁺ using an inverse emulsification polymerization. The morphology, particle size, pH sensitivity, and mechanism of cross-linking between COO^- and Fe³⁺ of the CMAX microgel was investigated. The CMAX microgel was used to be an oral protein drug carrier. The CMAX microgel particles exhibited a stable spherical structure. FT-IR spectral analysis of the CMAX microgel indicated that the microgel was crosslinked by bridging Fe³⁺ and COO^- with unidentate binding. The CMAX microgel exhibited good pH sensitivity and high stability in acid condition. Additionally, BSA was used as the embedding protein, and the controlled release effect of CMAX microgel was explored in gastrointestinal tract simulation.

Fiber degrading enzymes increased monosaccharides release and fermentation in corn distillers dried grains with solubles and wheat middlings steeped without or with protease

Treating fibrous feed ingredients with exogenous feed enzymes may improve their utilization in monogastric animals. An in vitro study was conducted to determine the effects of steeping corn distillers dried grains with solubles (DDGS) or wheat middlings (WM) with exogenous feed enzymes. Four treatments were arranged as follows: 1) co-product steeped with water (CON), 2) CON plus 0.5-g fiber degrading enzymes (FDE), 3) CON plus 0.5-g protease (PRO), and 4) CON plus 0.5-g FDE and 0.5 g PRO (FDEPRO). The FDE contained about 62,000, 37,000, and 8,000 U/g of xylanase, cellulase, and β-glucanase, respectively, whereas activities in PRO amounted to 2,500,000, 1,300,000, and 800,000 U/g of acid, alkaline, and neutral proteases, respectively. Briefly, 50 g of DDGS or WM samples (n = 8) were mixed with 500-mL water with or without enzymes and steeped for 0 to 72 h at 37 °C with continuous agitation. The pH, concentration of monosaccharides, and organic acids in the supernatant and apparent disappearance (AD) of fiber in solids were measured at 0, 12, 24, 48, and 72 h. There was treatment and time interaction (P < 0.005) on monosaccharides concentration. At 12 h, arabinose and glucose concentrations were similar (P > 0.05) between FDE and FDEPRO but higher (P = 0.002) than for CON in DDGS. For WM, FDE, and FDEPRO had higher (P < 0.001) xylose concentration than CON and PRO, whereas glucose concentration was higher (P < 0.001) for enzymes than CON at 12 h. However, FDEPRO had higher (P < 0.001) xylose concentration than CON, whereas xylose concentration for FDE and PRO was intermediate at 24 h. There was an interaction (P < 0.05) between treatment and time effect on lactic acid concentration in DDGS and WM (P < 0.005), and acetic acid concentration in WM (P < 0.001). In general, monosaccharide concentration was higher between 12 and 24 h and decreased after 48 h, whereas the pH decreased, and concentration of organic acids increased continuously over time (P < 0.05). The AD of NDF and ADF in DDGS was greater (P = 0.001) for FDE and FDEPRO than CON and PRO at 72 h. In WM, enzymes increased (P = 0.007) AD of NDF relative to CON at 72 h. Nonetheless, greater (P < 0.05) AD of fiber was observed between 48 and 72 h. In conclusion, although there were differences in responses among co-products, fiber degrading enzymes increased release of fermentable monosaccharides from co-products at 12 to 24 h of steeping and these effects were not extended with the addition of protease.

Structural characteristics and rheological properties of alkali-extracted arabinoxylan from dehulled barley kernel

Arabinoxylan (BIF-60) was isolated from barley water-insoluble fiber (BIF) by ethanol precipitation at 60 % (v/v). BIF-60 was composed of xylose (48.5 %) and arabinose (30.3 %). Its average molecular weight was 1360 kDa. Methylation and 1D/2D NMR analysis showed that BIF-60 possessed β-(l→4)-xylan as backbone, comprised of un-substituted (1,4-linked β-Xylp, 56.9 %), mono-substituted (1,2,4-linked and 1,3,4-linked β-Xylp, 22.1 %) and di-substituted (1,2,3,4-lin4ked β-Xylp, 18.4 %) xylose units, as well as other residues (T-Araf-(1→, T-Xylp-(1→, →5)-Araf-(1→, →2)-Araf-(1→, →3)-Araf-(1→ and →4)-Glcp-(1→). BIF-60 exhibited shear-thinning behaviour, low gel stability and weak gelling ability at high concentrations. This work provides a theoretical and experimental basis for molecular structure and properties of the alkali-extracted arabinoxylan from barley kernel, which could guide further functional research and application of barley-derived arabinoxylan.

Cascade extraction of proteins and feruloylated arabinoxylans from wheat bran

A cascade process for the sequential recovery of proteins and feruloylated arabinoxylan from wheat bran is proposed, involving a protein isolation step, enzymatic destarching and subcritical water extraction. The protein isolation step combining lactic acid fermentation and cold alkaline extraction reduced the recalcitrance of wheat bran, thus improving the total yields of the subsequent subcritical water extraction. The time evolution of subcritical water extraction of feruloylated arabinoxylan was compared at two temperatures (160 °C and 180 °C). Longer residence times enhanced the purity of target feruloylated arabinoxylans, whereas higher temperatures resulted in faster extraction at the expense of significant molar mass reduction. The radical scavenging activity of the extracted feruloylated arabinoxylans was preserved after the initial protein isolation step. This study opens new possibilities for the cascade valorization of wheat bran into enriched protein and non-starch polysaccharide fractions, which show potential to be used as functional food ingredients.

Covalently Cross-Linked Nanoparticles Based on Ferulated Arabinoxylans Recovered from a Distiller’s Dried Grains Byproduct

The purpose of this investigation was to extract ferulated arabinoxylans (AX) from dried distillers’ grains with solubles (DDGS) plus to investigate their capability to form covalently cross-linked nanoparticles. AX registered 7.3 µg of ferulic acid/mg polysaccharide and molecular weight and intrinsic viscosity of 661 kDa and 149 mL/g, correspondingly. Fourier transform infrared spectroscopy (FTIR) was used to confirm the identity of this polysaccharide. AX formed laccase induced covalent gels at 1% (w/v), which registered an elastic modulus of 224 Pa and a content of FA dimers of 1.5 µg/mg polysaccharide. Scanning electron microscopy pictures of AX gels exhibited a microstructure resembling a rough honeycomb. AX formed covalently cross-linked nanoparticles (NAX) by coaxial electrospray. The average hydrodynamic diameter of NAX determined by dynamic light scattering was 328 nm. NAX presented a spherical and regular shape by transmission electron microscopy analysis. NAX may be an attractive material for pharmaceutical and biomedical applications and an option in sustainable DDGS use.

Effects of Growth Conditions and Cultivar on the Content and Physiochemical Properties of Arabinoxylan in Barley

The present study aims to evaluate the effect of the growth conditions and the cultivar on the total and water-extractable (W-E) arabinoxylan (AX) in barley. For this purpose, nine barley varieties from two different years were analyzed. The total AX content ranged from 5.97 to 8.98 wt % d.m., while the W-E AX ranged from 0.06 to 0.35 wt % d.m. The W-E AX molecular properties were characterized by high-pressure size exclusion chromatography (HPSEC)-triple detector array (TDA). The molecular weight was between 2.3 × 10⁵ and 12.6 × 10⁵ Da, the polydispersity was between moderate and broad (1.1 < M_w/M_n < 4.3), and the conformation was a stiff semiflexible coil (0.5 < α < 1.3). The results indicate that the year influences the content of total AX and W-E AX and some molecular characteristics of W-E AX, such as its polydispersity and its conformation. Finally, the results demonstrated that the W-E AX can be used as an index of the malting attitude of barley because it positively correlates with germinative energy and kernel dimension.

Synthesis of Arabinoxylan Oligosaccharides by Preactivation-Based Iterative Glycosylations

A concise synthetic strategy has been developed for assembling densely substituted arabinoxylan oligosaccharides, which are valuable substrates for characterizing hemicellulose-degrading enzymes. The xylan backbone has been prepared by an iterative preactivation-based glycosylation approach with phenyl thioglycosides. The preactivation has been performed with in situ generated p-nitrobenzenesulfenyl triflate prior to addition of the acceptor. The glycosylation temperature was shown to have an important impact on the yield of the coupling. The arabinose substituents have been introduced in one high-yielding glycosylation with an N-phenyl trifluoroacetimidate donor. The strategy has been successfully employed for the synthesis of three heptasaccharides in seven steps and overall yields of 24-36% from the corresponding monosaccharide building blocks.