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Increasing interest in biopolymers moves their knowledge frontiers. One area undergoing this development is polysaccharides. The practical and theoretical significance of studying polysaccharides lies in the numerous essential functions these macromolecules fulfill in living organisms, and the important industrial and technological purposes they serve. Polysaccharides are thought to be abundant in marine microalgae; nevertheless, little is known about their sulfated polysaccharides. We studied Chaetoceros muelleri sulfated polysaccharide (CMSP) chain conformation, physical characteristics, and morphology. The CMSP spectrum generated from Fourier-transform infrared analysis displayed distinctive bands for these macromolecules. S=O and C–O–S signals were detected at 1225 and 820 cm−1, respectively, confirming the presence of sulfate in the molecules. The biopolymer registered weight-average molar mass, intrinsic viscosity ([η]), radius of gyration (RG), hydrodynamic radius (Rh), and sulfate degree of substitution of 1933 kDa, 577 mL/g, 62 nm, 44 nm, and 0.5 (sulfates per disaccharide repeat unit), respectively. The exponent α and the coefficient K in the Mark-Houwink-Sakurada (MHS) equation were 0.76 and 9.76 x 10−3 mL/g, respectively. These values suggest a flexible and compact random coil structure in CMSP. The sample's zeta potential (ζ), conductivity, and diffusion coefficient (D) were −26.43 mV, −2.07 µm cm/s V, 1.25 mS/cm, and 1.8 × 10−8 cm2/s, correspondingly. The negative charge in the molecules is related to the sulfate groups contained. The CMSP surface was coarse and craggy, according to scanning electron microscopy (SEM). The information generated in this present study contributes to elucidating characteristics as fundamental knowledge to understand the macromolecule functionality.

Marine algae are a valuable source of sulfated polysaccharides presenting varied structural characteristics and biological activities. Regarding sulfated polysaccharides extracted from marine microalgae, molecular characteristics and bioactivity have yet to be fully explored, especially in diatoms. Sulfated polysaccharides from marine diatoms have great potential to produce numerous health benefits and lead to new biomedical materials. Nevertheless, these potential applications are based on the polysaccharide molecular characteristics, which define their functional properties. Therefore, a detailed understanding of sulfated polysaccharides from marine diatoms may represent the starting point for a broad development of innovative applications, especially in the biomedical area. In this context, the present manuscript aims to review marine diatom sulfated polysaccharides' molecular characteristics and biological activity, looking for a more profound knowledge of these macromolecules and their potential applications.

Marine algae are a valuable source of polysaccharides. However, the information available on sulfated polysaccharides from microalgae is limited. Navicula sp. is a microalga present in the Sea of Cortez, of which little is known regarding their polysaccharides’ properties. This study investigated the physicochemical and microstructural characteristics of Navicula sp. sulfated polysaccharide (NSP). The Fourier transform infrared spectrum of NSP showed distinctive bands (1225 and 820 cm−1, assigned to S–O and C–O–S stretching, respectively), confirming the molecular identity. NSP registered molecular weight, intrinsic viscosity, a radius of gyration, and a hydrodynamic radius of 1650 kDa, 197 mL/g, 61 nm, and 36 nm, respectively. The zeta potential, electrophoretic mobility, conductivity, and diffusion coefficient of the molecule were −5.8 mV, −0.45 µm cm/s V, 0.70 mS/cm, and 2.9 × 10−9 cm2/s, respectively. The characteristic ratio and persistence length calculated for NSP were 4.2 and 1.3 nm, suggesting a nonstiff polysaccharide chain conformation. The Mark–Houwink–Sakurada α and K constants were 0.5 and 1.67 × 10−1, respectively, indicating a molecular random coil structure. NSP scanning electron microscopy revealed a rough and porous surface. Knowing these polysaccharides’ physicochemical and microstructural characteristics can be the starting point for elucidating their structure–function relationship as a valuable tool in advanced biomaterial design.

Arabinoxylans (AXs) extracted from distillers dried grains with solubles (DDGSs) were treated with amylase, amyloglucosidase, and protease, to evaluate their effect on the polysaccharide capability to form covalent electro-sprayed nanoparticles. Enzymatically treated arabinoxylans (AXPPs) presented a significant decrease in protein content and molecular weight (31 and 37%, respectively), while the ferulic acid content and the arabinose-to-xylose ratio (A/X) were not statistically modified. The Fourier transform infrared spectra of the AXPPs showed a diminution in the intensity of amide I and amide II bands concerning AXs. The AXPP gels (1% w/v) induced via laccase registered a slight increase in the dimers of ferulic acid cross-linking content (9%) and the G’ value (27%) about the AX gels. The electro-sprayed nanoparticles of AXs and AXPPs (NAXs and NAXPPs, respectively) revealed a spherical and regular morphology via transmission electron microscopy. The nanoparticle diameter was not different for the NAXs and NAXPPs, while the NAXPPs show a significant reduction in Z potential value compared to NAXs. Confocal laser microscopy observations were conducted, to analyze the protein content in the AX network, and a decrease in illuminated areas was observed in the AXPP gels and the NAXPPs. These results indicate that the enzymatical treatment of an AX improves the polysaccharide gelling capability, but does not influence the fabrication of electro-sprayed covalent nanoparticles. NAXs and NAXPPs could be attractive biomaterials for diverse pharmaceutical and biomedical applications.

Arabinoxylans (AX) and protease treated AX (AXP) were subjected to enzymatic hydrolysis with endoxylanase and arabinofuranosidase to obtain hydrolyzed AX (HAX) and AXP (HAXP), whose ability to promote Bifidobacterium infantis and Bifidobacterium longum growth was investigated. Further, the effect of cross-linked AX on the growth of bifidobacteria was also explored. Bifidobacteria showed the highest growth on AX and AXP, while HAX and HAXP did not have a significant impact on bacterial growth. The laccase cross-linking of AX stimulated the growth of bifidobacteria, possibly due to its gel-like structure which favored the bacteria-substrate (AX) interaction. The laccase-induced cross-linked AX (AXG) and alginate (SA) were used to prepare encapsulating matrices. The ability of AXG-SA matrices to encapsulate and protect probiotic bacteria (Lactobacillus rhamnosus GG, Streptococcus thermophilus and B. longum) viability under storage conditions was investigated. The AXG matrices presented the highest encapsulation efficiencies (55–77%) for all three strains, when AXG-SA and SA matrices were compared. Significantly higher levels (∼7 logs) of L. rhamnosus GG were recovered from AXG and AXG-SA matrices after 28 days of storage under aerobic conditions at 4 °C compared to SA matrices (∼4 logs). The results indicated that the incorporation of AX into the matrices played a significant role on the survival of encapsulated bacteria during storage, which could be attributed to the stability of the covalent cross-linked network formed during AX gelation that protected bacterial viability. Thus, the matrices based on AXG could be promising materials to encapsulate and protect probiotic bacteria for targeted-delivery to the colon.

Diabetes mellitus (DM) has a high incidence of comorbidities among patients with severe coronavirus disease 2019 (COVID-19). The elevated prevalence of DM in the world population makes it a significant risk factor because diabetic individuals appear to be prone to clinical complications and have increased mortality rates. Here, we review the possible underlying mechanisms involved in DM that led to worse outcomes in COVID-19. The impacts of hyperglycemia side effects, secondary comorbidities, weakened innate and adaptive immunity, chronic inflammation, and poor nutritional status, commonly present in DM, are discussed. The role of the SARS-CoV-2 receptor and its polymorphic variations on higher binding affinity to facilitate viral uptake in people with DM were also considered. Clinical differences between individuals with type 1 DM and type 2 DM affected by COVID-19 and the potential diabetogenic effect of SARS-CoV-2 infection were addressed.

Polysaccharide biomaterials have gained significant importance in the manufacture of nanoparticles used in colon-targeted drug delivery systems. These systems are a form of non-invasive oral therapy used in the treatment of various diseases. To achieve successful colonic delivery, the chemical, enzymatic and mucoadhesive barriers within the gastrointestinal (GI) tract must be analyzed. This will allow for the nanomaterials to cross these barriers and reach the colon. This review provides information on the development of nanoparticles made from various polysaccharides, which can overcome multiple barriers along the GI tract and affect encapsulation efficiency, drug protection, and release mechanisms upon arrival in the colon. Also, there is information disclosed about the size of the nanoparticles that are usually involved in the mechanisms of diffusion through the barriers in the GI tract, which may influence early drug degradation and release in the digestive tract.

Biological properties of Sonoran propolis (SP) are influenced by harvest time. Caborca propolis showed cellular protective capacity against reactive oxygen species, which might be implicated in anti-inflammatory effects. However, the anti-inflammatory activity of SP has not been investigated so far. This study investigated the anti-inflammatory activity of previously characterized seasonal SP extracts (SPE) and some of their main constituents (SPC). The anti-inflammatory activity of SPE and SPC was evaluated by measuring nitric oxide (NO) production, protein denaturation inhibition, heat-induced hemolysis inhibition, and hypotonicity-induced hemolysis inhibition. SPE from spring, autumn, and winter showed a higher cytotoxic effect on RAW 264.7 cells (IC50: 26.6 to 30.2 µg/mL) compared with summer extract (IC50: 49.4 µg/mL). SPE from spring reduced the NO secretion to basal levels at the lowest concentration tested (5 µg/mL). SPE inhibited the protein denaturation by 79% to 100%, and autumn showed the highest inhibitory activity. SPE stabilized erythrocyte membrane against heat-induced and hypotonicity-induced hemolysis in a concentration-dependent manner. Results indicate that the flavonoids chrysin, galangin, and pinocembrin could contribute to the anti-inflammatory activity of SPE and that the harvest time influences such a property. This study presents evidence of SPE pharmacological potential and some of their constituents.

Arabinoxylans (AX) are gelling polysaccharides with potential applications as colon-targeted biomaterials. Nevertheless, the fermentation of highly cross-linked AX particles (AXP) by colonic bacteria and the effect of its fermentation supernatants on the proliferation of human colon cancer cells have not been investigated so far. In this study, electrosprayed AXP were fermented by Bifidobacterium longum, Bifidobacterium adolescentis, and Bacteroides ovatus. The effect of AXP fermentation supernatant (AXP-fs) on the inhibition of the human colon cancer cell line Caco-2 proliferation was investigated. AXP presented a mean diameter of 533 µm, a spherical shape, and a cross-linking content (dimers and trimers of ferulic acid) of 1.65 µg/mg polysaccharide. After 48 h of bacteria exposure, AXP were only partly fermented, probably due to polymeric network steric hindrance that limits the access of bacterial enzymes to the polysaccharide target sites. AXP partial fermentation was evidenced by a moderate short-chain fatty acid production (SCFA) (23 mM) and a collapsed and disintegrated microstructure revealed by scanning electron microscopy. AXP-fs exerted slight inhibition of Caco-2 cell proliferation (11%), which could be attributed to the SCFA generated during partly polysaccharide fermentation. These findings indicate that electrosprayed AXP are a slow-fermentable biomaterial presenting slight anti-cancer properties and potential application in colon cancer prevention.

Mango by-products are important sources of bioactive compounds generated by agro-industrial process. During mango processing, 35–60% of the fruit is discarded, in many cases without treatment, generating environmental problems and economic losses. These wastes are constituted by peels and seeds (tegument and kernel). The aim of this review was to describe the extraction, identification, and quantification of bioactive compounds, as well as their potential applications, published in the last ten years. The main bioactive compounds in mango by-products are polyphenols and carotenoids, among others. Polyphenols are known for their high antioxidant and antimicrobial activities. Carotenoids show provitamin A and antioxidant activity. Among the mango by-products, the kernel has been studied more than tegument and peels because of the proportion and composition. The kernel represents 45–85% of the seed. The main bioactive components reported for the kernel are gallic, caffeic, cinnamic, tannic, and chlorogenic acids; methyl and ethyl gallates; mangiferin, rutin, hesperidin, and gallotannins; and penta-O-galloyl-glucoside and rhamnetin-3-[6-2-butenoil-hexoside]. Meanwhile, gallic acid, ferulic acid, and catechin are reported for mango peel. Although most of the reports are at the laboratory level, they include potential applications in the fields of food, active packaging, oil and fat, and pharmaceutics. At the market level, two trends will stimulate the industrial production of bioactive compounds from mango by-products: the increasing demand for industrialized fruit products (that will increase the by-products) and the increase in the consumption of bioactive ingredients.

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.

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.

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.

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.

Sugar beet is a potential source of pectin, competitive with traditional sources, that has recently acquired great relevance for its interesting covalent gelling and applications in food and biomedical industries. Pectins from three Sugar beet (Beta vulgaris L.) commercial cultivars (Cadet, Coronado large, and SV MEI) were grown under irrigated desertic conditions and the influence of cultivar, on pectin yield, composition, physicochemical and gelling characteristics was investigated. The composition and chemical properties of pectin from the three cultivars were in general, statistically different, especially in the Syngenta Cadet cultivar, presenting higher protein (10.3%), neutral sugars (21.6%), galacturonic acid (55%) and ferulic acid (5.5 mg/g) content, which are important parameters for gel formation. All pectins gelled via oxidative coupling and the main ferulic acid dimers found were 8-5′ and 8-O-4′. Pectin from Cadet cultivar formed gels with higher hardness (6.65 N) and adhesiveness (12.2 N) values than the other two varieties. The results indicate that pectin composition is affected by the sugar beet cultivars reported herein, especially in ferulic acid content, which confer the covalent gelling capability. Sugar beet cultivars grown under desert conditions could be a source of gelling ferulated pectins for the food industry, as valuable as those obtained in temperate conditions.

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 × 107 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.

Arabinoxylans (AX) are polysaccharides with antioxidant activity and emulsifying properties, which make them an attractive alternative for its potential application as a natural antioxidant in oils. Therefore, this work aimed to investigate the effect of ultrasonic treatment of AX on their antioxidant capacity and its ability to improve the oxidative stability of soybean oil. For this purpose, AX were exposed to ultrasonic treatment at 25% (100 W, AX-1) and 50% (200 W, AX-2) power and an operating frequency of 20 KHz during 15 min, and their macromolecular properties (weight average molecular weight (Mw), polydispersity index and intrinsic viscosity) were evaluated. The antioxidant capacity of AX was determined by the DPPH assay and Rancimat test. Results showed that ultrasonic treatment did not affect the molecular identity of the polysaccharide but modified its Mw distribution. AX-1 showed the highest antioxidant activity (75% inhibition) at 533 µg/mL by the DPPH method compared to AX and AX-2. AX at 0.25% (w/v) and AX-1 at 0.01% (w/v) exerted the highest protective effects on oxidative stability of soybean oil with induction periods of 7.69 and 5.54 h, respectively. The results indicate that AX could be a good alternative for the potential application as a natural antioxidant in oils.

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.

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.

In the present study water extractable arabinoxylans (WEAX) from a Mexican spring wheat flour (cv. Tacupeto F2001) were isolated, characterized and gelled and the gel rheological properties and microstructure were investigated. These WEAX presented an arabinose to xylose ratio of 0.66, a ferulic acid and diferulic acid content of 0.526 and 0.036 µg/mg WEAX, respectively and a Fourier Transform Infra-Red (FT-IR) spectrum typical of arabinoxylans. The intrinsic viscosity and viscosimetric molecular weight values for WEAX were 3.5 dL/g and 504 kDa, respectively. WEAX solution at 2% (w/v) formed gels induced by a laccase as cross-linking agent. Cured WEAX gels registered storage (G’) and loss (G’’) modulus values of 31 and 5 Pa, respectively and a diferulic acid content of 0.12 µg/mg WEAX, only traces of triferulic acid were detected. Scanning electron microscopy analysis of the lyophilized WEAX gels showed that this material resembles that of an imperfect honeycomb.

Water extractable arabinoxylan (WEAX) aerogels were prepared by extracting the solvent from the alcogels (WEAX hydrogels with an alcohol as the solvent) with carbon dioxide under supercritical conditions. WEAX aerogels were characterized using scanning electron microscopy and adsorption and desorption nitrogen isotherms. The micrographs indicate a heterogeneous porous network structure in WEAX aerogel. Adsorption/desorption nitrogen isotherms of this material were type IV, which confirm that this material possess a mesoporous structure. WEAX aerogels rehydration capability was evaluated and the water absorption mechanism was determined. The WEAX aerogels water absorption mechanism was non-Fickian (n = 0.54).

The aim of this research was to study the structural and textural characteristics of maize bran arabinoxylan (MBAX) microspheres. The laccase-induced cross-linking process was monitored by storage (G') and loss (G'') moduli changes in a 4% (w/v) MBAX solution. The G' and G'' values at the plateau region were 215 and 4 Pa, respectively. After gelation, the content of ferulic acid dimers decreased from 0.135 to 0.03 µg/mg MBAX, suggesting the formation of ferulated structures unreleased by mild alkaline hydrolysis. MBAX microspheres presented an average diameter of 531 µm and a swelling ratio value (q) of 18 g water/g MBAX. The structural parameters of MBAX microspheres were calculated from equilibrium swelling experiments, presenting an average mesh size of 52 nm. Microstructure and textural properties of dried MBAX microspheres were studied by scanning electron microscopy and nitrogen adsorption/desorption isotherms, respectively, showing a heterogeneous mesoporous and macroporous structure throughout the network.

Arabinoxylan gels exhibiting different rheological and lycopene transport properties were obtained by modifying the polysaccharide concentration from 3 to 4% (w/v). The apparent lycopene diffusion coefficient decreased from 2.7 × 10−7 to 2.4 × 10−7 cm2/s as the arabinoxylan concentration in the gel changed from 3 to 4% (w/v). A low amount of lycopene is released by diffusion from arabinoxylan gels. These results indicate that arabinoxylan gels could be carriers for lycopene delivery in specific sites after network degradation. The possibility to modulate lycopene release from arabinoxylan gels makes these biomaterials potential candidates for the controlled delivery of biomolecules.

The oxidative gelation of maize bran arabinoxylans (MBAX) using a peroxidase/H2O2 system as a free radical-generating agent was investigated. The peroxidase/H2O2 system led to the formation of dimers and trimer of ferulic acid as covalent cross-link structures in the MBAX network. MBAX gels at 4% (w/v) presented a storage modulus of 180 Pa. The structural parameters of MBAX gels were calculated from swelling experiments. MBAX gels presented a molecular weight between two cross-links (Mc), a cross-linking density (ρc) and a mesh size (x) of 49 × 103 g/mol, 30 × 10−6 mol/cm3 and 193 nm, respectively.