Gelation of Arabinoxylans from Maize Wastewater — Effect of Alkaline Hydrolysis Conditions on the Gel Rheology and Microstructure

The purpose of this research was to extract arabinoxylans (AX) from maize wastewater generated under different maize nixtamalization conditions and to investigate the polysaccharide gelling capability, as well as the rheological and microstructural characteristics of the gels formed. The nixtamalization conditions were 1.5 hours of cooking and 24 hours of alkaline hydrolysis (AX1) or 30 minutes cooking and 4 hours of alkaline hydrolysis (AX2). AX1 and AX2 presented yield values of 0.9% and 0.5% (w/v), respectively. Both AX samples presented similar molecular identity (Fourier Transform Infra-Red) and molecular weight distribution but different ferulic acid (FA) content. AX1 and AX2 presented gelling capability under laccase exposure. The kinetics of gelation of both AX samples was rheologically monitored by small amplitude oscillatory shear. The gelation profiles followed a characteristic kinetics with an initial increase in the storage modulus (G\u27) and loss modulus (G") followed by a plateau region for both gels. AX1 presented higher G\u27 than AX2. In scanning electron microscopy (SEM) images, both gels present an irregular honeycomb microstructure. The lower FA content in AX2 form gels presenting minor elasticity values and a more fragmented microstructure. These results indicate that nixtamalization process conditions can modify the characteristics of AX gels

Métodos de extracción, funcionalidad y bioactividad de saponinas de Yucca: una revisión

Saponins are secondary metabolites produced naturally by plants due to biotic stress. Plants of the Yucca genus are considered source of saponins, particularly steroidal glycosides. Due to their chemical structure, they are molecules with diverse functional properties and biological activity. This document critically explores the reported technological procedures to obtain saponins and saponin rich extracts from species of the Yucca genus, as well their properties, bioactivity and current applications. Yucca saponin extracts are considered to have potential for industrial application in various areas, particularly in food technology, health and agriculture.Las saponinas son metabolitos secundarios producidos naturalmente por las plantas debido al estrés biótico. Las plantas del género Yucca se consideran fuente de saponinas, particularmente de glucósidos esteroidales. Debido a su estructura química, son moléculas con diversas propiedades funcionales y con actividad biológica. Este documento explora de manera crítica los procesos tecnológicos reportados para la obtención de saponinas y extractos con saponinas de diversas especies del género Yucca, así como sus propiedades, bioactividad y aplicaciones actuales. Se considera que los extractos con saponinas de yuca presentan un potencial de uso a nivel industrial en diversas áreas, particularmente en tecnología de alimentos, salud y agropecuaria

Acemannan Gels and Aerogels

The procedures to obtain two types of acemannan (AC) physical gels and their respective aerogels are reported. The gelation was induced by the diffusion of an alkali or a non-solvent, then supercritical CO2 drying technology was used to remove the solvent out and generate the AC aerogels. Fourier-transform infrared spectroscopic analysis indicated that alkali diffusion produced extensive AC deacetylation. Conversely, the non-solvent treatment did not affect the chemical structure of AC. Both types of gels showed syneresis and the drying process induced further volume reduction. Both aerogels were mesoporous nanostructured materials with pore sizes up to 6.4 nm and specific surface areas over 370 m2/g. The AC physical gels and aerogels enable numerous possibilities of applications, joining the unique features of these materials with the functional and bioactive properties of the AC

Formulation and characterization of gentamicin-loaded albumin microspheres as a potential drug carrier for the treatment of E. coli K88 infections

The aim of this study was to formulate and characterize gentamicin-loaded albumin microspheres for their potential therapeutic use in E. coli K88 infections. Based on in vitro assays, it is proposed that microspheres may serve as a carrier of gentamicin and may provide localized antibacterial activity in the treatment of porcine colibacillosis. Gentamicin-albumin microspheres (GAM) were obtained using a water/oil (W/O) emulsion followed by cross-linking with different concentrations of glutaraldehyde. Electron microscopy showed spherical particles with indentations. The average size of the GAM was 10.5-12.3 µm. At pH 7.2, the release kinetics of gentamicin from the GAM was successfully described as an initial burst defined by a first order equation.  Gentamicin release was unaffected by the glutaraldehyde concentrations used but was affected by acidic conditions.  The behavior of gentamicin release from the GAM was not altered by digestion with trypsin and chymotrypsin at pH 7.2. Additionally, the concentration of gentamicin released from GAM to reach antibacterial activity was similar to that of free gentamicin against E. coli K88. This work shows the potential use of GAM as therapeutic vehicles of gentamicin to counteract intestinal infections in pig

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

Enzymatic Cross-Linking of Alkali Extracted Arabinoxylans: Gel Rheological and Structural Characteristics

Ferulated arabinoxylans were alkali-extracted from wheat bran at different incubation times (0.0, 0.5, 1.0, 1.5 and 2.0 h). Wheat bran ferulated arabinoxylans (WBAX) arabinose-to-xylose ratio, ferulic acid content, intrinsic viscosity and viscosimetric molecular weight values decreased as the incubation time of extraction increased. WBAX enzymatic cross-linking capability was affected by incubation time while an increase in WBAX concentration from 5 to 6% (w/v) favored gelation. The WBAX gels formed presented a macroporous structure with mesh size ranging from 40 to 119 nm and hardness values varying from 1.7 to 5 N

A Novel Pectin Material: Extraction, Characterization and Gelling Properties

A novel pectin was acid extracted from chickpea husk (CHP). CHP presented a 67% (w/w) of galacturonic acid, an intrinsic viscosity of 374 mL/g and a viscosimetric molecular weight of 110 kDa. Fourier transform infrared spectroscopy spectrum of CHP indicated a degree of esterification of about 10%. The CHP-calcium system formed ionic gels with a storage (G′) modulus of 40 Pa and gel set time (G′ > G″) of 3 min at 1% (w/v), and a G′ of 131 Pa and gel set time of 1 min at 2% (w/v). The G′ of CHP gels was not greatly affected by temperature. The results attained suggest that chickpea husk can be a potential source of a gelling pectin material

Chitosan and Other Edible Coatings with Antimicrobial Activity: Synthesis, Properties and Horticultural Applications

Antimicrobial edible coatings for whole or fresh-cut fruits and vegetables based on natural biopolymers that serve as carriers of antimicrobial agents or that are inherently antimicrobial, such as chitosan, are increasingly gaining interest from researchers and industry due to their potential to maintain quality and safety. Additionally, edible coatings can also function as a barrier to water vapors and gases, regulating physiological aspects in fruit. Despite the substantial research progress in antimicrobial edible coatings for fresh and fresh-cut fruits and vegetables, the development of tailor-made solutions according to specific commercialization needs still represents a technological challenge due to important physical, physiological, and biochemical differences among the wide variety of fresh horticultural commodities. The development of edible films and coatings with antimicrobial activity requires knowledge of the chemical bases to develop optimized edible coating formulations, the effects of the coatings on different postharvest pathogens in in vitro studies and in different fruit matrices, as well as their effect on fruit quality during postharvest storage