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BACKGROUND: 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. RESULTS: 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. CONCLUSION: 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.

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The processes to obtain value-added products from brewers' spent grain, a contaminant industrial waste, require alkaline non-ecofriendly pre-treatments. The arabinoxylans from brewers' spent grain were extracted by nixtamalization evaluating the extraction procedure, antioxidant capacity and molecular characteristics. The best arabinoxylans yields were those extracted with CaO at 100 °C and 25 °C (6.43% and 3.37%, respectively). The antioxidant capacity by 2,2-diphenyl-1-picrylhydrazyl assay of the arabinoxylans after thermal treatment and additional arabinoxylans after thermal treatment proteolysis were 434 and 118 mg TE/g, while by 2,20'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) diammonium salt assay the value was similar (380 µmol TE/g). The intrinsic viscosities and viscosimetric molecular weights were 69 mL/g and 13 kDa for arabinoxylans after thermal treatment, and 15 mL/g and 1.6 kDa for arabinoxylans after thermal treatment proteolysis, respectively. The protein and lignin contents were 3.1% and 6.4% for arabinoxylans after thermal treatment and, 0.9% and 4.6% for arabinoxylans after thermal treatment proteolysis, while their arabinose: xylose ratios were 0.39 and 0.36, with ferulic acid contents of 0.63 and 0.14 mg/g, respectively. Both products of arabinoxylans were molecularly identical by Fourier transform infra-red. Although the purity of the extracted arabinoxylans was improved with proteolysis, their intrinsic viscosity and viscosimetric molecular weight were affected. The extraction of arabinoxylans from brewers' spent grain by CaO nixtamalization alone or after additional proteolysis was successful to obtain purity and good antioxidant capacity.

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In the present study, a culture of Chaetoceros muelleri, a cosmopolitan planktonic diatom microalga present in the Sea of Cortez, was established under controlled laboratory conditions. A sulfated polysaccharide (CMSP) extraction was carried out from the biomass obtained, resulting in a yield of 2.2% (w/w of dry biomass). The CMSP sample was analyzed by Fourier transform infrared spectroscopy, showing bands ranging from 3405 to 590 cm-1 and a sulfate substitution degree of 0.10. Scanning electron microscopy with elemental analysis revealed that the CMSP particles are irregularly shaped with non-acute angles and contain sulfur. High-performance liquid chromatography coupled to a dynamic light-scattering detector yielded molecular weight (Mw), polydispersity index (PDI), intrinsic viscosity [η], and hydrodynamic radius (Rh) values of 4.13 kDa, 2.0, 4.68 mL/g, and 1.3 nm, respectively, for the CMSP. This polysaccharide did not present cytotoxicity in CCD-841 colon cells. The antioxidant activity and the glycemic index of the CMSP were 23% and 49, respectively, which gives this molecule an added value by keeping low glycemic levels and exerting antioxidant activity simultaneously.

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Arabinoxylans (AX) microcapsules loaded with insulin were prepared by enzymatic gelation of AX, using a triaxial electrospray method. The microcapsules presented a spherical shape, with an average size of 250 µm. The behavior of AX microcapsules was evaluated using a simulator of the human intestinal microbial ecosystem. AX microcapsules were mainly (70%) degraded in the ascending colon. The fermentation was completed in the descending colon, increasing the production of acetic, propionic, and butyric acids. In the three regions of the colon, the fermentation of AX microcapsules significantly increased populations of Bifidobacterium and Lactobacillus and decreased the population of Enterobacteriaceae. In addition, the results found in this in vitro model showed that the AX microcapsules could resist the simulated conditions of the upper gastrointestinal system and be a carrier for insulin delivery to the colon. The pharmacological activity of insulin-loaded AX microcapsules was evaluated after oral delivery in diabetic rats. AX microcapsules lowered the serum glucose levels in diabetic rats by 75%, with insulin doses of 25 and 50 IU/kg. The hypoglycemic effect and the insulin levels remained for more than 48 h. Oral relative bioavailability was 13 and 8.7% for the 25 and 50 IU/kg doses, respectively. These results indicate that AX microcapsules are a promising microbiota-activated system for oral insulin delivery in the colon.

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Large volumes of fruit and vegetable production are lost during postharvest handling due to attacks by necrotrophic fungi. One of the promising alternatives proposed for the control of postharvest diseases is the induction of natural defense responses, which can be activated by recognizing molecules present in pathogens, such as chitin. Chitin is one of the most important components of the fungal cell wall and is recognized through plant membrane receptors. These receptors belong to the receptor-like kinase (RLK) family, which possesses a transmembrane domain and/or receptor-like protein (RLP) that requires binding to another RLK receptor to recognize chitin. In addition, these receptors have extracellular LysM motifs that participate in the perception of chitin oligosaccharides. These receptors have been widely studied in Arabidopsis thaliana (A. thaliana) and Oryza sativa (O. sativa); however, it is not clear how the molecular recognition and plant defense mechanisms of chitin oligosaccharides occur in other plant species or fruits. This review includes recent findings on the molecular recognition of chitin oligosaccharides and how they activate defense mechanisms in plants. In addition, we highlight some of the current advances in chitin perception in horticultural crops.

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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.

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Ferulated polysaccharides such as pectin and arabinoxylan form covalent gels which are attractive for drug delivery or cell immobilization. Saccharomyces boulardii is a probiotic yeast known for providing humans with health benefits; however, its application is limited by viability loss under environmental stress. In this study, ferulated pectin from sugar beet solid waste (SBWP) and ferulated arabinoxylan from maize bioethanol waste (AX) were used to form a covalent mixed gel, which was in turn used to entrap S. boulardii (2.08 × 108 cells/mL) in microbeads using electrospray. SBWP presented a low degree of esterification (30%), which allowed gelation through Ca2+, making it possible to reduce microbead aggregation and coalescence by curing the particles in a 2% CaCl2 cross-linking solution. SBWP/AX and SBWP/AX+ S. boulardii microbeads presented a diameter of 214 and 344 µm, respectively, and a covalent cross-linking content (dimers di-FA and trimer tri-FA of ferulic acid) of 1.15 mg/g polysaccharide. The 8-5', 8-O-4'and 5-5'di-FA isomers proportions were 79%, 18%, and 3%, respectively. Confocal laser scanning microscopy images of propidium iodide-stained yeasts confirmed cell viability before and after microbeads preparation by electrospray. SBWP/AX capability to entrap S. boulardii would represent an alternative for probiotic immobilization in tailored biomaterials and an opportunity for sustainable waste upcycling to value-added products.

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This study evaluated the effect of using arabinoxylans (AX) and gelled arabinoxylans (AxGel) as anti-obesogenic agents on the faecal microbiota of rats fed with a high-fat (HF) diet. Results revealed that the HF content in diet caused obesity in rats and alterations in the taxonomic and functional profiles of faecal microbiota. However, these effects were lessened when AX and AxGel were used as ingredients of the HF diet. Metabolisms of amino acids and energy, as well as genetic information processing, were negatively affected when the rats consumed the HF diet; however, this effect was not observed if AX and AxGel were included as part of the diet formulation. Results suggest that AX may act as a prebiotic agent. Therefore, AX and AxGel could be considered as hypothetical protectors of the intestinal microbiota against HF consumption.

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Background and objectives: Arabinoxylans (AX) can gel and exhibit antioxidant capacity. Previous studies have demonstrated the potential application of AX microspheres as colon-targeted drug carriers. However, the cytotoxicity of AX gels has not been investigated so far. Therefore, the aim of the present study was to prepare AX-based particles (AXM) by coaxial electrospraying method and to investigate their antioxidant potential and cytotoxicity on human colon cells. Materials and Methods: The gelation of AX was studied by monitoring the storage (G') and loss (G'') moduli. The morphology of AXM was evaluated using optical and scanning electron microscopy (SEM). The in vitro antioxidant activity of AX before and after gelation was measured using the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS+), 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) methods. In addition, the effect of AX and AXM on the proliferation of human colon cells (CCD 841 CoN) was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Results: The final G' and G'' values for AX gels were 293 and 0.31 Pa, respectively. AXM presented spherical shape and rough surface with a three-dimensional and porous network. The swelling ratio and mesh size of AXM were 35 g water/g AX and 27 nm, respectively. Gelation decreased the antioxidant activity of AX by 61-64 %. AX and AXM did not affect proliferation or show any toxic effect on the normal human colon cell line CCD 841 CoN. Conclusion: The results indicate that AXM could be promising biocompatible materials with antioxidant activity.

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RESUMEN Los arabinoxilanos son polisacáridos presentes en los granos de los cereales, y como tales, forman parte de la fibra dietética consumida por humanos y animales. La hidrólisis química o enzimática de los arabinoxilanos produce arabinoxilo-oligosacáridos, los cuales pueden estar ramificados o no, con arabinosa. El objetivo de este trabajo fue exponer el uso potencial de los arabinoxilanos y arabinoxilo-oligosacáridos, como prebióticos, y el efecto de su consumo en la promoción de la buena salud, al estimular selectivamente el crecimiento y actividad metabólica de la microbiótica colónica benéfica. La información generada indica que los arabinoxilanos y arabinoxilo-oligosacáridos actúan modificando la microbiota de manera selectiva, y estimulan la respuesta biológica, favoreciendo la buena salud del hospedero, por su efecto antiobesogénico, regulador de la glucosa, antioxidante, anticancerígeno e inmunomodulador, con resultados similares o mejores en relación a prebióticos reconocidos. No obstante, es necesario ampliar el conocimiento que se tiene de ellos para sustentar su aplicación en la industria alimentaria, farmacéutica o biomédica.

ABSTRACT Arabinoxylans are polysaccharides present in grains and as such, are part of dietary fiber intake in humans and animals. Enzymatic or chemical hydrolysis of arabinoxylans produces arabinoxilo-oligosaccharides, which can be branched or unbranched with arabinose. The objective of this work was to describe the potential use of arabinoxylans and arabinoxylan-oligosaccharides as prebiotics to promote good health, by selective enhancement of beneficial colonic microbiota growth and metabolic activity. The information generated indicates that arabinoxylans and arabinoxylan-oligosaccharides act by modifying the microbiota selectively and stimulate the biological response favoring good health in the host, by antio-obesity effect, glucose regulator, antioxidant, anticancer, immunomodulator, with similar or better results than recognized prebiotics. However, it is necessary to expand the knowledge we have about arabinoxylans in order to support their application in the food, pharmaceutical, and biomedical industry.

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In the last years, biomedical research has focused its efforts in the development of new oral delivery systems for the treatment of different diseases. Ferulated arabinoxylans are polysaccharides from cereals that have been gaining attention in the pharmaceutical field due to their prebiotic, antioxidant, and anticancer properties. The antioxidant and anticancer properties of these polysaccharides make them attractive compounds for the treatment of cancer, particularly colon cancer. In addition, ferulated arabinoxylans can form covalent gels through the cross-linking of their ferulic acids. Due to their particular characteristics, ferulated arabinoxylan gels represent an excellent alternative as colon-targeted drug delivery systems. The aim of the present work is to review the physicochemical and functional properties of ferulated arabinoxylans and their gels and to present the future perspectives for potential application as antioxidant and anticancer agents.

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Pectins are plant cell wall natural heteropolysaccharides composed mainly of α-1-4 d-galacturonic acid units, which may or may not be methyl esterified, possesses neutral sugars branching that harbor functional moieties. Physicochemical features as pH, temperature, ions concentration, and cosolute presence, affect directly the extraction yield and gelling capacity of pectins. The chemical and structural features of this polysaccharide enables its interaction with a wide range of molecules, a property that scientists profit from to form new composite matrices for target/controlled delivery of therapeutic molecules, genes or cells. Considered a prebiotic dietary fiber, pectins meetmany regulations easily, regarding health applications within the pharmaceutical industry as a raw material and as an agent for the prevention of cancer. Thus, this review lists many emergent pectin-based composite materials which will probably palliate the impact of obesity, diabetes and heart disease, aid to forestall actual epidemics, expand the ken of food additives and food products design.

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Aggregation and coalescence are major drawbacks that contribute to polydispersity in microparticles and nanoparticles fabricated from diverse biopolymers. This study presents the evaluation of a novel method for the direct, electrospray-induced fabrication of small, CaCl2/ethanol-hardened low methoxy pectin/arabinoxylans composite microbeads. The electrospray method was evaluated to control particle size by adjusting voltage, flux, and crosslinking solution content of CaCl2/ethanol. A bead diameter of 1µm was set as reference to test the capability of this method. Insulin was chosen as a model carried molecule. Statistical analysis was a central composite rotatable design (CCRD) with a factorial arrangement of 24. The variables studied were magnitude and particle size dispersion. For the determination of these variables, light diffraction techniques, scanning electron microscopy, transmission electron microscopy, and confocal laser scanning microscopy were used. Major interaction was found for ethanol and CaCl2 as well as flow and voltage. Stable spherical structures of core⁻shell beads were obtained with neither aggregation nor coalescence for all treatments where ethanol was included in the crosslinking solution, and the average diameter within 1 ± 0.024 µm for 11 KV, 75% ethanol with 11% CaCl2, and flow of 0.97 mL/h.

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BACKGROUND: Arabinoxylans (AX) are polysaccharides consisting of a backbone of xyloses with arabinose substituents ester-linked to ferulic acid (FA). The arabinose to xylose ratio (A/X) in AX may vary from 0.3 to 1.1. AX form covalent gels by cross-linking of FA but physical interactions between AX chains also contribute to the network formation. The present study aimed to investigate the rheological and microstructural characteristics of gels based on AX enzymatically modified in A/X. RESULTS: Tailored AX presented A/X ranging from 0.68 to 0.51 and formed covalent gels. Dimers of FA content and elasticity (G') increased from 0.31 to 0.39 g kg-1 AX and from 106 to 164 Pa when the A/X in the polysaccharide decreased from 0.68 to 0.51. Atomic force microscopy images of AX gels showed a sponge-like microstructure at A/X = 0.68, whereas, at lower values, gels presented a more compact microstructure. Scanning electron microscopy analysis of AX gels show an arrangement of different morphology, passing from an imperfect honeycomb (A/X = 0.68) to a flake-like microstructure (A/X = 0.51). CONCLUSION: Lower A/X values favor the aggregation of AX chains resulting in an increase in di-FA content, which improves the rheological and microstructural characteristics of the gel formed. © 2017 Society of Chemical Industry.

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Jumbo squid (Dosidicus gigas) muscle proteins show low functionality with limited use in gel products. This work aims to assess the influence of adding the natural and commercially available fibre, amidated low-methoxyl pectin (at 0.5, 1.0, 1.5, 2.0 and 3.0%), on the physicochemical and functional characteristics of jumbo squid (Dosidicus gigas) mantle muscle gels. The addition of 0.5% fibre showed an immediate effect on the gel texture profile analysis, improving hardness (p<0.05) from (3.4±0.7) N of the control (no added fibre) to (5.2±0.9) N, and increasing elasticity (p≥0.05). Shear force was significant only at 3.0% fibre addition. Water holding capacity also improved (p<0.05) with fibre addition (from 75% in the control to 90-95% after the treatments). Whiteness was affected (p<0.05) when 3.0% fibre was added. Differential scanning calorimetry showed two endothermic transition peaks in the gels. The second peak (actin) increased (p<0.05) by 1-2 °C with fibre addition. Therefore, the present study demonstrates that amidated low-methoxyl pectin (0.5-3.0%) is an excellent ingredient to improve jumbo squid mantle muscle protein functionality, increasing the gel texture and water retention characteristics.

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Arabinoxylans (AXs) with high ferulic acid (FA) content (7.18 µg/mg AXs) were cross-linked using laccase. Storage (G') modulus of AX solutions at 1% (AX-1) and 2% (AX-2) (w/v) registered maximum values of 409 Pa and 889 Pa at 180 min and 83 min, respectively. Atomic force microscopy revealed the grained and irregular surface of the AX-1 gel and the smoother surface without significant depressions of the AX-2 gel. Cured AX gels exhibited a liquid phase surrounding the samples indicating syneresis. The syneresis ratio percentage (% Rs) of the gels was registered over time reaching stabilization at 20 h. The % Rs was not significantly different between AX-1 (60.0%) and AX-2 (62.8%) gels. After 20 h of syneresis development, the dimers of the FA in the AX-1 and AX-2 gels significantly increased by 9% and 78%, respectively; moreover, the trimers of the FA in the AX-1 and AX-2 gels, by 94% and 300%, respectively. Scanning electron microscopy showed that, after syneresis stabilization, AX gels presented a more compact microstructure. Syneresis development in the gels of highly ferulated AXs could be related to the polymer network contraction due to the additional formation of dimers and trimers of the FA (cross-linking structures), which may act like a "zipping" process, increasing the polymer chains' connectivity.

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In the present study, wheat water extractable arabinoxylans (WEAX) were isolated and characterized, and their capability to form covalently cross-linked films in presence of Debaryomyces hansenii was evaluated. WEAX presented an arabinose to xylose ratio of 0.60, a ferulic acid and diferulic acid content of 2.1 and 0.04 µg∙mg(-1) WEAX, respectively and a Fourier Transform Infra-Red (FT-IR) spectrum typical of WEAX. The intrinsic viscosity and viscosimetric molecular weight values for WEAX were 3.6 dL∙g(-1) and 440 kDa, respectively. The gelation of WEAX (1% w/v) with and without D. hansenii (1 × 10(7) CFU∙cm(-2)) was rheologically investigated by small amplitude oscillatory shear. The entrapment of D. hansenii decreased gel elasticity from 1.4 to 0.3 Pa, probably by affecting the physical interactions between WEAX chains. Covalently cross-linked WEAX films containing D. hansenii were prepared by casting. Scanning electron microscopy images show that WEAX films containing D. hansenii were porous and consisted of granular-like and fibre microstructures. Average tensile strength, elongation at break and Young's modulus values dropped when D. hansenii was present in the film. Covalently cross-lined WEAX containing D. hansenii could be a suitable as a functional entrapping film.

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Micro- and nanotechnology are tools being used strongly in the area of food technology. The electrospray technique is booming because of its importance in developing micro- and nanoparticles containing an active ingredient as bioactive compounds, enhancing molecules of flavors, odors, and packaging coatings, and developing polymers that are obtained from food (proteins, carbohydrates), as chitosan, alginate, gelatin, agar, starch, or gluten. The electrospray technique compared to conventional techniques such as nanoprecipitation, emulsion-diffusion, double-emulsification, and layer by layer provides greater advantages to develop micro- and nanoparticles because it is simple, low cost, uses a low amount of solvents, and products are obtained in one step. This technique could also be applied in the agrifood sector for the preparation of controlled and/or prolonged release systems of fertilizer or agrochemicals, for which more research must be conducted.

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Wheat bran arabinoxylan (WBAX) gels entrapping standard model proteins at different mass ratios were formed. The entrapment of protein affected the gel elasticity and viscosity values, which decreased from 177 to 138 Pa. The presence of protein did not modify the covalent cross-links content of the gel. The distribution of protein through the network was investigated by confocal laser scanning microscopy. In mixed gels, protein aggregates forming clusters were detected at protein/polysaccharide ratios higher than 0.25. These clusters were not homogeneously distributed, suggesting that WBAX and protein are located in two different phases. The apparent diffusion coefficient (Dm) of proteins during release from mixed gels was investigated for mass ratios of 0.06 and 0.12. For insulin, Dm increased significantly from 2.64 × 10-7 to 3.20 × 10-7 cm2/s as the mass ratio augmented from 0.06 to 0.12. No significant difference was found for Dm values of ovalbumin and bovine serum albumin released from the mixed gels. The results indicate that homogeneous protein/WBAX gels can be formed at low mass ratios, allowing the estimation of Dm by using an analytical solution of the second Fick's law.

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Due to their porous structure, aqueous environment and dietary fiber nature arabinoxylan (AX) gels could have potential applications for colon-specific therapeutic molecule delivery. In addition, prebiotic and health related effects of AX have been previously demonstrated. It has been also reported that cross-linked AX can be degraded by bacteria from the intestinal microbiota. However, AX gels have not been abundantly studied as carrier systems and there is no information available concerning their capability to entrap cells. In this regard, probiotic bacteria such as Bifidobacterium longum have been the focus of intense research activity lately. The objective of this research was to investigate the entrapment of probiotic B. longum in AX gels. AX solution at 2% (w/v) containing B. longum (1 × 107 CFU/cm) formed gels induced by laccase as cross-linking agent. The entrapment of B. longum decreased gel elasticity from 31 to 23 Pa, probably by affecting the physical interactions taking place between WEAX chains. Images of AX gels containing B. longum viewed under a scanning electron microscope show the gel network with the bacterial cells entrapped inside. The microstructure of these gels resembles that of an imperfect honeycomb. The results suggest that AX gels can be potential candidates for the entrapment of probiotics.

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