Protein/arabinoxylans gels: effect of mass ratio on the rheological, microstructural and diffusional characteristics

Characterization of feruloylated arabinoxylan - acorn starch double network gel composite film and its application in postharvest preservation of Agaricus bisporus

To obtain efficient natural food packaging materials, we utilized acorn starch (AS)-based film strengthened by feruloylated arabinoxylan (FAX) gel and additional retrogradation treatment to extend the shelf life of Agaricus bisporus (A. bisporus). Fourier transform infrared spectroscopy (FT-IR), confocal laser scanning microscopy (CLSM), and scanning electron microscopy (SEM) analyses showed that due to the strong hydrogen bonding between FAX and starch molecules, physical crosslinking occurred between FAX and starch molecules in the composite film, and the microstructure became more compact. Thermogravimetric, tensile strength and swelling degree analyses indicate that the composite film exhibits better thermal stability, mechanical properties, and waterproofing compared to the pure AS film. Consequently, after five days of storage, the moisture content of the A. bisporus packaged with our composite film was 7.53 times and 5.73 times higher than that of the control group and the commercially available PEF group, respectively. Moreover, it delayed the respiration or transpiration of A. bisporus (lower weight loss, relative conductivity, MDA content). This packaging film developed with the objective of eco-friendly and biodegradability has considerable application potential in food and other industries.

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.

Antimicrobial activity of thermophilin 110 against the opportunistic pathogen Cutibacterium acnes

OBJECTIVE

Thermophilin 110, a bacteriocin produced by Streptococcus thermophilus B59671, inhibited planktonic growth and biofilm formation of Cutibacterium acnes, a commensal skin bacterium associated with the inflammatory disease, acne vulgaris, and more invasive deep tissue infections.

RESULTS

Thermophilin 110 prevented planktonic growth of C. acnes at a concentration ≥ 160 AU mL-1; while concentrations ≥ 640 AU mL-1 resulted in a > 5 log reduction in viable planktonic cell counts and inhibited biofilm formation. Arabinoxylan (AX) and sodium alginate (SA) hydrogels were shown to encapsulate thermophilin 110, but as currently formulated, the encapsulated bacteriocin was unable to diffuse out of the gel and inhibit the growth of C. acnes. Hydrogels were also used to encapsulate S. thermophilus B59671, and inhibition zones were observed against C. acnes around intact SA gels, or S. thermophilus colonies that were released from AX gels.

CONCLUSIONS

Thermophilin 110 has potential as an antimicrobial for preventing C. acnes infections and further optimization of SA and AX gel formulations could allow them to serve as delivery systems for bacteriocins or bacteriocin-producing probiotics.

Design and structural characterization of edible double network gels based on wheat bran arabinoxylan and pea protein isolate

Double network (DN) gels based on wheat bran arabinoxylan (WBAX) and pea protein isolate (PPI) were fabricated by a two-step sequential gelation method with laccase catalyzed cross-linking followed by heating. The rheological properties, water holding capacity, microstructure and molecular structure of WBAX/PPI DN gels were investigated. Increasing the concentrations of WBAX and PPI contributed to an enhanced viscoelastic modulus of DN gel, which exhibited an interconnected, bicontinuous and compact structure with smaller pore sizes, as a result of higher cross-linking intensity of WBAX molecules. Low field nuclear magnetic resonance (LF-NMR) results showed that increasing the contents of PPI and WBAX could further restrict the water mobility within DN gel, which was beneficial for enhancing the water holding capacity of gel samples. The molecular structure analysis showed that the crosslinking of WBAX-WBAX, PPI-PPI and WBAX-PPI participated in the formation of WBAX-PPI DN gels.

Fabrication and biomedical applications of Arabinoxylan, Pectin, Chitosan, Soy protein, and Silk fibroin hydrogels via laccase - ferulic acid redox chemistry

The unique physiochemical properties and the porous network architecture of hydrogel seek the attention to be explored in broad range of fields. In the last decade, numerous studies on the development of enzymatically cross-linked hydrogels have been elucidated. Implementing enzyme based cross-linking for fabrication of biomaterials over other crosslinking methods harbor various advantages, especially hydrogels designed using laccase exhibits mild reaction environment, high cross-linking efficiency and less toxicity. To our knowledge this is the first report reviewing the formulation of laccase mediated cross-linking for hydrogel preparation. Here, laccase catalyzed synthesis of hydrogel using polysaccharide viz. arabinoxylan, sugar beet pectin, galactomannan, chitosan etc. and proteins namely soy protein, gelatin, silk fibroin were discussed on highlighting their mechanical properties and its possible field of application. We have summarized the role of phenolic acids in laccase mediated crosslinking particularly ferulic acid which is a component of lignocellulose, serving cell rigidity via crosslinkage. The review also discusses on various biomedical applications such as controlled protein release, tissue engineering, and wound healing. It is anticipated that this review will give a detailed information on different laccase mediated reaction strategies that can be applied for the synthesis of various new biomaterials with tailor made properties.

Characterization of Soluble Glandless Cottonseed Meal Proteins Based on Electrophoresis, Functional Properties, and Microscopic Structure

This investigation aimed to extract and characterize the GCSM proteins, determine their solubility potential at two different temperatures and different solvents, and explore their functional properties. During the extraction, no water- or ethanol-soluble protein was found. Most of the protein was extracted with KOH solution. GCSM showed major protein bands between 13,273 and 56,564 Da with an isoelectric point of 5.1. The results showed that extraction temperature and solvent affected the amount of protein extracted from GCSM. The highest protein yield (63.4%) was obtained with KOH at 55 °C. Fat content negatively affected the protein solubility. The highest protein purity (99.9%) was obtained with 6% of fat content and the lowest one with 19% of fat content. GCSM has a high glutamic acid content, followed by arginine and aspartic acid compared to the other amino acids. The essential amino acids make up about 30.0% of the total amino acid concentration in KOH-soluble fractions. The results showed a denaturation temperature of GCSM protein ranging from 61.4 to 63.6 °C. Scanning electron microscopy reveals a microglobular protein structure. GCSM protein isolate showed lower (P < 0.05) water-holding and oil-holding capacity but similar gelation properties as soy protein. GCSM protein shows a high foaming capacity at high pH values and high emulsion stability. PRACTICAL APPLICATION: The results of this investigation have a direct impact on the plant protein processing industry. This paper presents a new source of plant protein with a high foaming capacity in alkaline conditions with potential applications for human consumption and feed for aquaculture and animals. The results of this research may impact the cotton producers who can increase their income, and the aquaculture industry will have a cheaper source of protein that can partially substitute the expensive fishmeal. Cottonseed protein can be used to develop high protein extruded snacks and other functional foods, such as plant protein-based food products.

Arabinoxylan-Based Particles: In Vitro Antioxidant Capacity and Cytotoxicity on a Human Colon Cell Line

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.

Enzymatic cross-linking of ferulated arabinoxylan: effect of laccase or peroxidase catalysis on the gel characteristics

Arabinoxylans (AX) gels at 4% (w/v) were prepared using laccase (LAX gels) or peroxidase (PAX gels), and their cross-linking, rheological, structural, and spectroscopic characteristics were investigated. LAX gels presented lower amount of 5,5'-diferulic acid (11%), smaller mesh size (128 nm), and higher hardness (37 N) and elasticity (430 Pa) than the PAX gels (28%, 197 nm, 7 N, and 120 Pa, respectively). Microscopy of the LAX gels showed linked strands, while the system was less connected in the PAX gels. The Raman band at 2895 cm-1 of the LAX and PAX gels was less intense, indicating enhanced hydrogen bonding compared to that of AX. This decrease was less dramatic for the PAX gels. The greater content of 5,5'-diferulic acid in PAX gels could favor intrachain bonds, affecting their rheological, structural, and spectroscopic characteristics. Laccase may be a better option than peroxidase for AX gelation intended for food and biotechnological applications.

Physicochemical characterization of an arabinoxylan-rich fraction from brewers' spent grain and its application as a release matrix for caffeine

The brewers' spent grain is a by-product generated during brewery process and is a potential source for arabinoxylans (AX) extraction. In the present work, the extraction and characterization of an arabinoxylan-rich fraction from brewers' spent grain (BSG-AX) were performed, and BSG-AX was evaluated as release matrix for caffeine. The BSG-AX showed an AX content of 72% (w/w), a ferulic acid content of 3.52 μg/mg BSG-AX, an Ara/Xyl ratio of 0.89, an intrinsic viscosity of 41.18 mL g^-1, and a molecular weight of 43.80 kDa. The studied BSG-AX showed a good antioxidant capacity compared with other polysaccharide gums and was estimated by DPPH (114.41 μM Trolox equivalent/g BSG-AX) and FRAP (49.01 μmol Fe²⁺/g BSG-AX) assays. The partial specific volume (0.63 cm³ g^-1), loss on drying (10.68%), swelling (10.87%), solubility (80.93%) and electrostatic interactions (by zeta potential, -3.44 to -9.17 mV) were determined and used to evaluate the application of the BSG-AX as release matrix. A film containing the BSG-AX, glycerol (as plasticizer) and caffeine (target drug) was prepared as release matrix. Glycerol promoted an increase in the extensibility and the surface smoothness of the BSG-AX-caffeine film. The drug was released (≈98%) in about 7 h. These results are promising to concern the design and use of BSG-AX based biofilms for the controlled release of bioactive compounds.

Carbohydrate Esterases: An Overview

Carbohydrate esterases are a group of enzymes which release acyl or alkyl groups attached by ester linkage to carbohydrates. The CAZy database, which classifies enzymes that assemble, modify, and break down carbohydrates and glycoconjugates, classifies all carbohydrate esterases into 16 families. This chapter is an overview of the research for nearly 50 years around the main groups of carbohydrate esterases dealing with the degradation of polysaccharides, their main biochemical and molecular traits, as well as its application for the synthesis of high added value esters.

Gelation of wheat arabinoxylans in the presence of Cu(+2) and in aqueous mixtures with cereal β-glucans

The effect of copper ions (0.63-0.16 mM) on the rheological behavior of arabinoxylan (AX) aqueous solutions was investigated. Moreover, the influence of β-glucan addition (BG, 0.5-3% w/v) on the gelation of mixed AX/BG solutions with and without addition of the peroxidase/H2O2 was examined. Generally, gels formed with inclusion of transition metal-ions differed from those obtained by adding peroxidase/H2O2. Copper ions induced viscosity increase of the AX-solutions and form stronger thermoreversible gels with increasing ion-concentration; optimal gelation was at 15 °C. For added β-glucan at levels >1%, the lower the concentration and the higher the molecular weight of β-glucan, the weaker the gelling ability of the mixed AX/BG system treated with peroxidase/H2O2. The polysaccharide-ratio affected both the gelling rate and the network melting temperature, with the β-glucan itself giving the strongest network. Calorimetry provided evidence for existence of β-glucan ordered domains in the mixed gel structures of AX/BG1, indicative of phase separation events.