Development of Polymeric Films Based on Sunflower Seed Proteins and Locust Bean Gum.

Most polymeric food packaging materials are non-biodegradable and derived from petroleum, thus recent studies have focused on evaluating alternative biodegradable materials from renewable sources, with polysaccharides and proteins as the main types of employed biopolymers. Therefore, this study aimed to develop biopolymeric films based on sunflower proteins and galactomannans from locust bean gum. The influence of the galactomannan amount (0.10%, 0.30%, 0.50%, and 0.75% w/v) on the physicochemical, thermal, and mechanical properties of cast sunflower protein-based films was studied. Sunflower proteins gave rise to yellowish, shining, and translucid films. With the incorporation of locust bean gum-derived galactomannans, the films became more brown and opaque, although they still maintained some translucency. Galactomannans significantly changed the proteins' secondary structures, giving rise to films with increased tensile resistance and stretchability. Nevertheless, the increase in the galactomannan amount did not have a significant effect on the film's thermal stability. The protein/galactomannan-based films showed values of water vapor and oxygen permeability that were slightly higher than those of the pristine materials. Overall, blending locust bean gum galactomannans with sunflower proteins was revealed to be a promising strategy to develop naturally colored and translucid films with enhanced mechanical resistance while maintaining flexibility, fitting the desired properties for biodegradable food packaging materials.

Ultrasonic depolymerization of aqueous tara gum solutions: kinetic, thermodynamic and physicochemical properties.

BACKGROUND: Tara gum (TG) is characterized by its high viscosity and medium solubility, which is a result of its high molecular mass. However, for many applications, these characteristics are undesirable, making the use of TG infeasible. The present study aimed to evaluate the effect of high-intensity ultrasound on the depolymerization of aqueous solutions of TG. The effect of ultrasonication was investigated by viscometry analysis as well as Fourier transform infrared spectroscopy (FTIR) and solubility. RESULTS: The intrinsic viscosity (η) and the molecular weight (Mw ) of TG decreased after ultrasound, achieving a molecular weight reduction of 13.50 × 105 g mol-1 after 60 min of sonication at 25 °C compared to 22.04 × 105 g mol-1 before treatment. Degradation kinetics were applied to estimate the rate constant of degradation (k). It was found that the k value of TG increased with increasing temperature from 25 to 55 °C. Partially hydrolyzed TG showed greater solubility at the two temperatures investigated (25 and 80 °C). Ultrasonic treatment did not change the chemical structure of the TG molecules according to the structural analysis by FTIR, confirming its action only as breaking the structure of the polymer. CONCLUSION: Ultrasound is a simple method for effectively reducing the molecular weight and viscosity and increasing the solubility of TG without using chemical reagents. The synthesis of partially hydrolyzed TG expands its potential for use in food products, including as a soluble dietary fiber. © 2022 Society of Chemical Industry.

SARS-CoV-2 and Aspergillus section Fumigati coinfection in an immunocompetent patient treated with corticosteroids.

BACKGROUND: Patients with severe viral pneumonia are likely to receive high-dose immunomodulatory drugs to prevent clinical worsening. Aspergillus species have been described as frequent secondary pneumonia agents in severely ill influenza patients receiving steroids. COVID-19 patients admitted to Intensive Care Unit (ICU) are receiving steroids as part of their treatment and they share clinical characteristics with other patients with severe viral pneumonias. COVID-19 patients receiving steroids should be considered a putative risk group of invasive aspergillosis. CASE REPORT: We are reporting a SARS-CoV-2/Aspergillus section Fumigati coinfection in an elderly intubated patient with a history of pulmonary embolism treated with corticosteroids. The diagnosis was made following the ad hoc definitions described for patients admitted to ICU with severe influenza, including clinical criteria (fever for 3 days refractory to the appropriate antibiotic therapy, dyspnea, pleural friction rub, worsening of respiratory status despite antibiotic therapy and need of ventilator support), a radiological criterion (pulmonary infiltrate) and a mycological criterion (several positive galactomannan tests on serum with ratio ≥0.5). In addition, Aspergillus section Fumigati DNA was found in serum and blood samples. These tests were positive 4 weeks after the patient was admitted to the ICU. The patient received voriconazole and after two month in ICU his respiratory status improved; he was discharged after 6 weeks of antifungal treatment. CONCLUSIONS: Severely ill COVID-19 patients would be considered a new aspergillosis risk group. Galactomannan and Aspergillus DNA detection would be useful methods for Aspergillus infection diagnosis as they allow avoiding the biosafety issues related to these patients.

Microencapsulation of vitamin D3 by complex coacervation using carboxymethyl tara gum (Caesalpinia spinosa) and gelatin A.

Vitamin D3 plays a fundamental role in human health; however, it is highly susceptible to environmental conditions and the gastrointestinal tract. In this study, complex coacervates obtained from gelatin A and carboxymethyl tara gum (CMTG) were used as wall materials for the encapsulation of vitamin D3 (VD3). Zeta potential and turbidity measurements were employed to optimize the pH and ratio (gelatin A:CMTG), and the results showed that the ideal conditions for the complex coacervation were pH 4.0 and a 6:1 ratio. The encapsulation efficiency (EE) was determined as a function of the total concentration of biopolymers (TC%) and the core-to-wall ratio, and the greatest EE (80%) was achieved at a TC of 1% and a ratio of 1:2; spherical particles with an average size of 0.25 µm were obtained. The microencapsulation increased the thermal stability of VD3, and FTIR confirmed the presence of the biopolymers and VD3 in the capsules. An in vitro simulation showed a more pronounced release in the small intestine with a vitamin bioaccessibility of 56%. The encapsulation of bioactive lipophilic compounds by complex coacervates of gelatin A and CMTG resulted in improved stability and prolonged release during digestion.

Hylan G-F20 and galactomannan joint flares are associated to acute synovitis and release of inflammatory cytokines.

BACKGROUND: Injection of Hylan G-F20 (HY) into joints may provoke local flares, which mechanisms may involve reaction to protein contaminants. We have previously developed a protein-free saline-soluble galactomannan derived from guar gum (GM) that displays both analgesia and chondroprotection in experimental osteoarthritis (OA). We now demonstrate that both GM and Hylan G-F20 (HY) promote mild synovitis with cytokine release after intra-articular injection. METHODS: Mice received 100 µg/25 µL GM or HY or saline into the knees. Joint pain was evaluated using von Frey test; cell influx, interleukin (IL)-1, IL-6, and CXCL-1 (pg/mL) levels were assessed in joint lavage at 6 h. Synovia were excised for histopathology. RESULTS: Neither GM nor HY after being given into mice knee joints induced pain albeit promoting mild cell influx into joint washings as well as mild synovitis at histology, with no damage to the underlying cartilage. HY but not GM promoted IL-1 release into mice joints. Both compounds induced IL-6 and CXCL-1 release. CONCLUSION: Intra-articular injection of HY or GM promote acute transient synovitis whilst not provoking detectable significant joint damage. Local administration of these polysaccharides induces acute intra-articular release of inflammatory cytokines, which may account for joint flares following viscosupplementation.

Polysaccharide-rich fraction of spent coffee grounds as promising biomaterial for films fabrication.

Spent coffee grounds are wastes generated annually worldwide in significantly large amounts in the soluble coffee industry and in household and commercial beverage preparation. Although spent coffee grounds are rich in several classes of compounds, predominantly polysaccharides, profitable applications have not yet been effectively implemented for such wastes. Thus, it was the aim of this study to verify the feasibility of producing biopolymeric films from the polysaccharide-rich fraction of spent coffee grounds, obtained by alkaline hydrogen peroxide treatment of the coffee waste. Produced films were characterized for their physicochemical, barrier and mechanical properties and these properties were comparable to those of similar polysaccharides films from the literature.

Effect of adding galactomannans on some physical and chemical properties of hyaluronic acid.

Hyaluronic acid (HA) and galactomannans (such as guar gum - GG and locust bean gum - LBG) are biomacromolecules with various applications due to their physicochemical characteristics in solution, especially their ability to form films or hydrogels in some conditions. Some of these applications are possible because they are nontoxic and biocompatible. Mixtures of HA and GG or LBG, at pH 7.4, were prepared at 25 g·L-1 of HA:LBG or HA:GG with percentages of 50:50, 60:40, 70:30 and 80:20 (w/w) and evaluated by rheology and NMR experiments regarding the interactions. The best synergism observed was between HA:LBG, most pronounced at 50% (w/w), where the dynamic modulus values G' and G″ indicated the formation of physical gels with viscoelastic behavior close to that of HA. 2D NOESY spectra revealed hydrogen interconnectivity of H-1 glucuronic acid units of HA with H-5 mannose units of the main galactomannan chains. This synergism, besides producing a hydrogel with interesting properties, also can decrease the cost by partially replacing HA in many applications, such as in nutraceutical foods, support for tissue engineering and cosmetics.

Hylan G-F20 and galactomannan joint flares are associated to acute synovitis and release of inflammatory cytokines

Abstract Background: Injection of Hylan G-F20 (HY) into joints may provoke local flares, which mechanisms may involve reaction to protein contaminants. We have previously developed a protein-free saline-soluble galactomannan derived from guar gum (GM) that displays both analgesia and chondroprotection in experimental osteoarthritis (OA). We now demonstrate that both GM and Hylan G-F20 (HY) promote mild synovitis with cytokine release after intra-articular injection. Methods: Mice received 100 μg/25 μL GM or HY or saline into the knees. Joint pain was evaluated using von Frey test; cell influx, interleukin (IL)-1, IL-6, and CXCL-1 (pg/mL) levels were assessed in joint lavage at 6 h. Synovia were excised for histopathology. Results: Neither GM nor HY after being given into mice knee joints induced pain albeit promoting mild cell influx into joint washings as well as mild synovitis at histology, with no damage to the underlying cartilage. HY but not GM promoted IL-1 release into mice joints. Both compounds induced IL-6 and CXCL-1 release. Conclusion: Intra-articular injection of HY or GM promote acute transient synovitis whilst not provoking detectable significant joint damage. Local administration of these polysaccharides induces acute intra-articular release of inflammatory cytokines, which may account for joint flares following viscosupplementation.(AU)

A phytomodulatory hydrogel with enhanced healing effects.

The healing performance of a hydrogel composed of hemicelluloses extracted from seeds of Caesalpinia pulcherrima (Fabaceae) and mixed with phytomodulatory proteins obtained from the latex of Calotropis procera was characterized on excisional wounds. The hydrogel did not induce dermal irritability. When topically used on excisional wounds, the hydrogel enhanced healing by wound contraction. Histology and the measurement of inflammatory mediators (myeloperoxidase, interleukin-1ß, and interleukin-6) suggested that the inflammatory phase of the healing process was intensified, stimulating fibroplasia and neovascularization (proliferative phase) and tissue remodeling by increasing new collagen fiber deposition. In addition, reduction on levels of malondialdehyde in the groups that the hydrogel was applied suggested that the oxidative stress was reduced. The hydrogel performed better than the reference drug used, as revealed by the extended thickness of the remodeled epithelium.

Toxicity of native and oxovanadium (IV/V) galactomannan complexes on HepG2 cells is related to impairment of mitochondrial functions.

Polysaccharides and vanadium compounds have been studied due to their antitumor potential. In this study, the cytotoxic effects of galactomannan preparations on HepG2 cells were investigated. Native galactomannan from S. amazonicum (SAGM) and its modified form (MSAGM) were complexed with oxovanadium resulting in SAGM:VO and MSAGM:VO, respectively. The complexation was confirmed by NMR, FTIR, and AAS. SAGM and MSAGM:VO (250µg/mL) after 72h decreased viability by 51% and 58%, respectively, while the inhibition of the HepG2 cell proliferation was of ∼27% and ∼46%, respectively. SAGM and MSAGM:VO (250µg/mL) significantly inhibited all states of respiration (basal: 85% and 63%; uncoupled: 90% and 70%; and leak: 30% and 58%) after 72h. ROS levels increased by ∼149% after the treatment with MSAGM:VO (250µg/mL) for 72h, while ΔΨm decreased by ∼50%. Our results indicate that galactomannan preparations from S. amazonicum, especially SAGM and the MSAGM:VO complex, could be considered as potential antitumor drugs for further investigations, once they have the ability to make HepG2 cells susceptible to death by affecting vital cellular processes such as respiration and ROS generation.

Galactomannan from Schizolobium amazonicum seed and its sulfated derivatives impair metabolism in HepG2 cells.

This study evaluated the effects of native galactomannan from Schizolobium amazonicum seeds and its sulfated forms on certain metabolic parameters of HepG2 cells. Aqueous extraction from S. amazonicum seeds furnished galactomannan with 3.2:1 Man:Gal ratio (SAGM) and molar mass of 4.34×105g/mol. The SAGM fraction was subjected to sulfation using chlorosulfonic acid to obtain SAGMS1 and SAGMS2 with DS of 0.4 and 0.6, respectively. Cytotoxicity of SAGM, SAGMS1, and SAGMS2 was evaluated in human hepatocellular carcinoma cells (HepG2). After 72h, SAGM decreased the viability of HepG2 cells by 50% at 250µg/mL, while SAGMS1 reduced it by 30% at the same concentration. SAGM, SAGMS1, and SAGMS2 promoted a reduction in oxygen consumption and an increase in lactate production in non-permeabilized HepG2 cells after 72h of treatment. These results suggest that SAGM, SAGMS1, and SAGMS2 could be recognized by HepG2 cells and might trigger alterations that impair its survival. These effects could be implicated in the modification of the oxidative phosphorylation process in HepG2 cells and activation of the glycolytic pathway.

TEMPO-mediated oxidation on galactomannan: Gal/Man ratio and chain flexibility dependence.

Guar (GG) and locust bean (LBG) galactomannans (GMs) oxidation at C-6 was performed with catalyst TEMPO, in which the reaction progress was monitored by consume of NaOH solution. The products were characterized by spectroscopic analysis, infrared, and (1)H-nuclear magnetic resonance, confirming the presence of aldehydes groups as intermediate of reaction to carboxylic acid. From high performance anion exchange chromatography with pulsed amperometric detection Man/Gal molar ratio was determined and demonstrated a preference to oxidize Man during the reaction on both GMs, following a first order kinetics of oxidation. The comparative macromolecular behavior of native and oxidized GMs was obtained through the analysis by high performance size exclusion chromatography, and the persistence length (Lp) was 6nm and 4nm to native LBG and GG, respectively. A more accessible OH-6 at mannose residue in LBG could be related with a two times faster reaction than GG. The selective oxidation with catalyst TEMPO proved to be efficient to increase the flexibility of the GMs during oxidation. Short reaction time and ß-elimination process were mainly observed to LBG, probably due to a more favorable oxidation access to the polysaccharide main chain.

Macromolecular and functional properties of galactomannan from mesquite seed (Prosopis glandulosa).

In this work, galactomannans from Prosopis glandulosa seeds were evaluated for their chemical composition and functional properties for potential industrial applications. In addition, those characteristics were compared with the commercial galactomannan guar gum. Mannose and galactose were the two most abundant carbohydrates present in P. glandulosa seeds, which represent 95.32% of total carbohydrates present in this material. Galactomannans from mesquite seed (GMS) yield was 16.53% and presented a M/G ratio of 2:1, which was higher than value observed for guar gum (1.6:1). The results obtained from functional properties showed that GMS has considerable potential to be considered as a food additive.

Evaluation of Caesalpinia pulcherrima endospermic gum as affinity matrices for galactose-binding lectins interaction

Lectins are proteins or glycoproteins able to bind, specifically and reversibly carbohydrates and glycoconjugates. Considering this ability, the utilization of Caesalpinia pulcherrima seeds polysaccharides as an affinity matrix was tested. The endospermic gum were solubilized in distinct concentrations of NaOH and treated with different amounts of epichlorohydrin (ECH) forming affinity gels with variable capacity for interaction with galactose- binding lectins. The gel with an ECH/gum ration of 6.0mmol/g was selected as the best affinity matrix. The matrix presented different efficiencies in terms of isolating galactose-binding lectins. C. pulcherrima endospermic galactomannans were purified by ethanol precipitation and the purified galactomannan was crosslinked with the best formulation of gel. The Artocarpus incisa, Ricinus communis and Abrus precatorius lectins showed interactions of 11.5, 17.7 and 47.2mg of retained protein in 1g of gel, respectively; the Artocarpus integrifolia lectin showed the highest affinities (79.7mg/g). The heamaglutination assays confirmed the activity and SDS-PAGE electrophoresis confirmed the isolation of the lectins in a single-step procedure.

Sediments in coffee extracts: Composition and control by enzymatic hydrolysis.

The water-insolubility of some coffee extract components is one of the major limitations in the production of instant coffee. In this work, fractions from coffee extracts and sediments were prepared, and their chemical composition determined. Based on the carbohydrate analysis, galactomannan was found to be the main polysaccharide component of the insoluble fractions and probably responsible for sediment formation. The suitability of twelve commercial enzymes for the hydrolysis of the insoluble fractions was investigated. Pectinase 444L was the most effective enzyme in releasing sugars, mainly mannose and galactose, from these substrates. Biopectinase CCM, Rohapect B1L, Pectinase 444L and Galactomannanase ACH were found to be the most effective enzymes for reducing the sediment of coffee extracts. The highest sediment reduction was obtained using Rohapect B1L and Galactomannanase ACH, at enzyme concentrations of 0.3 and 0.1mg protein/g substrate, respectively.