Alginate Cryogels as a Template for the Preparation of Edible Oleogels.

A high consumption of solid fats is linked to increased inflammation and a risk of cardiovascular diseases. Hence, in recent years, there has been increasing interest in the development of oleogels as a fat substitute in food products. Oleogels are edible gels that contain a large amount of liquid oils entrapped in a 3D network and that can potentially be applied to spreads, bakery goods, meat, and dairy products in order to lower their saturated fat content while maintaining a desirable food texture and mouthfeel. In this work, alginate cryogels were studied as templates for three different edible oils in the process of oleogel formation. Two different freezing regimes to obtain cryogels were employed in order to evaluate better the textural and morphological capabilities of cryogels to adsorb and retain edible oils. It was shown that rapid freezing in liquid nitrogen produces alginate cryogels with a lower density, higher porosity, and a greater ability to adsorb the tested oils. The highest uptake and holding oil capacity was achieved for olive oil, which reached a value of 792% and 82%, respectively. The best chewiness was found for an oleogel containing olive oil, whereas oleogels with the other two tested oils showed better springiness. Hence, the results presented in this work demonstrated that alginate-based cryogels can be effectively used as templates for oleogels and potentially find applications in the food industry.

Extracted Eucalyptus globulus Bark Fiber as a Potential Substrate for Pinus radiata and Quillaja saponaria Germination.

This study aimed to explore alternative substrates for growing forest species using eucalyptus bark. It evaluated the potential of extracted Eucalyptus globulus fiber bark as a substitute for commercial growing media such as coconut fiber, moss, peat, and compost pine. We determined the physicochemical parameters of the growing media, the germination rate, and the mean fresh and dry weights of seedlings. We used the Munoo-Liisa Vitality Index (MLVI) test to evaluate the phytotoxicity of the bark alone and when mixed with commercial substrates. Generally, the best mixture for seed growth was 75% extracted eucalyptus bark fiber and 25% commercial substrates. In particular, the 75E-25P (peat) mixture is a promising substitute for seedling growth of Pinus radiata, achieving up to 3-times higher MLVI than the control peat alone. For Quillaja saponaria, the best growth substrate was the 50E-50C (coconut fiber) mixture, which had the most significant MLVI values (127%). We added chitosan and alginate-encapsulated fulvic acid phytostimulants to improve the performance of the substrate mixtures. The fulvic acid, encapsulated or not, significantly improved MLVI values in Q. saponaria species and P. radiata in concentrations between 0.05 and 0.1% w/v. This study suggests that mixtures with higher levels of extracted fiber are suitable for growing forest species, thus promoting the application of circular economy principles in forestry.

Influence of chitin nanofibers and gallic acid on physical-chemical and biological performances of chitosan-based films.

In this work, chitosan films loaded with gallic acid and different content of chitin nanofibers were prepared and subjected to different characterization techniques. The results showed that the inclusion of gallic acid to chitosan films caused moderate decrease in water vapor permeability (by 29 %) and increased tensile strength of films (by 169 %) in comparison to the neat chitosan films. Furthermore, it was found that the addition of chitin nanofibers up to 30 % into chitosan/gallic acid films additionally improved tensile strength (by 474 %) and reduced plasticity of films (by 171 %), when compared to the chitosan/gallic acid films. Increased concentration of chitin nanofibers in films reduced the overall water vapor permeability of films by 51 %. In addition, gallic acid and chitin nanofibers had synergic effect on high chitosan film's antioxidant and antifungal activity toward Botrytis cinerea (both above 95 %). Finally, chitosan/gallic acid/chitin nanofibers films reduced decay incidence of strawberries, increased total soluble solid content, and promoted high production of some polyphenols during cold storage, in comparison to the control chitosan films and uncoated strawberry samples. Hence, these results suggest that chitosan/gallic acid/chitin nanofibers can present eco-sustainable approach for preservation of strawberries, giving them additional nutritional value.

Characterization of Chilean hot spring-origin Staphylococcus sp. BSP3 produced exopolysaccharide as biological additive.

A type of high molecular weight bioactive polymers called exopolysaccharides (EPS) are produced by thermophiles, the extremophilic microbes that thrive in acidic environmental conditions of hot springs with excessively warm temperatures. Over time, EPS became important as natural biotechnological additives because of their noncytotoxic, emulsifying, antioxidant, or immunostimulant activities. In this article, we unravelled a new EPS produced by Staphylococcus sp. BSP3 from an acidic (pH 6.03) San Pedro hot spring (38.1 °C) located in the central Andean mountains in Chile. Several physicochemical techniques were performed to characterize the EPS structure including Scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS), Atomic Force Microscopy (AFM), High-Performance Liquid Chromatography (HPLC), Gel permeation chromatography (GPC), Fourier Transform Infrared Spectroscopy (FTIR), 1D Nuclear Magnetic Resonance (NMR), and Thermogravimetric analysis (TGA). It was confirmed that the amorphous surface of the BSP3 EPS, composed of rough pillar-like nanostructures, is evenly distributed. The main EPS monosaccharide constituents were mannose (72%), glucose (24%) and galactose (4%). Also, it is a medium molecular weight (43.7 kDa) heteropolysaccharide. NMR spectroscopy demonstrated the presence of a [→ 6)-⍺-D-Manp-(1 → 6)-⍺-D-Manp-(1 →] backbone 2-O substituted with 1-⍺-D-Manp. A high thermal stability of EPS (287 °C) was confirmed by TGA analysis. Emulsification, antioxidant, flocculation, water-holding (WHC), and oil-holding (OHC) capacities are also studied for biotechnological industry applications. The results demonstrated that BSP3 EPS could be used as a biodegradable material for different purposes, like flocculation and natural additives in product formulation.

Ugi efficient synthesis of novel N-alkylated lipopeptides, antimicrobial properties and computational studies in Staphylococcus aureus via MurD antibacterial target.

Lipopeptides are medicinally essential building blocks with strong hemolytic, antifungal and antibiotic potential. In the present research article, we are presenting our findings regarding the synthesis of N-alkylated lipopeptides via Ugi four-component approach, their antimicrobial potential against pathogenic (Gram-positive and Gram-negative) bacteria, as well as computational studies to investigate the compounds binding affinity and dynamic behavior with MurD antibacterial target. Molecular docking demonstrated the compounds have good binding ability with MurD enzyme. The FT94, FT95 and FT97 compounds revealed binding affinity scores of -8.585 kcal mol- 1, -7.660 kcal mol- 1 and -7.351 kcal mol- 1, respectively. Furthermore, dynamics analysis pointed the systems high structure dynamics. The docking and simulation results were validated by binding free energies, demonstrating solid intermolecular interactions and in the assay in vitro, the Minimal Inhibitory Concentration (MIC) of FT97 to Staphylococcus aureus (S. aureus) was 62.5 µg/mL. In conclusion, a moderate inhibitory response of peptoid FT97 was observed against the Gram-positive bacteria, S. aureus and B. cereus.

Value-added long-chain aliphatic compounds obtained through pyrolysis of phosphorylated chitin.

In this work, chitin, as a biobased polymer, is used as a precursor to obtain a phosphorylated derivatives. The influence of the different degree of phosphorylation in chitin on pyrolysis pattern was investigated. In order to understand the pyrolysis mechanism and the potential application of phosphorylated chitins, the samples were pyrolyzed at different temperatures and analyzed by FTIR, SEM, and Py-GC/MS analysis. Moreover, the thermal degradation and the evolved gases during chitin degradation and its derivatives were measured. The results showed that phosphorylation of chitin decreased the thermal stability of biopolymer and significantly changed the pattern of pyrolysis compared to neat chitin. The production of long-chain hydrocarbons was detected during pyrolysis of phosphorylated chitin, whereas this was not the case with raw chitin. Those two effects were more pronounced as the degree of phosphorylation increased. Chitin with the degree of phosphorylation (DS 1.35) exhibited the highest selectivity (91 %) towards production of long-chain hydrocarbons (C12-C17) at 500 °C. Moreover, the obtained results allowed to propose, for the first time, the mechanism of pyrolysis of phosphorylated chitin.

Rational Design of Hydrogels for Cationic Antimicrobial Peptide Delivery: A Molecular Modeling Approach.

In light of the growing bacterial resistance to antibiotics and in the absence of the development of new antimicrobial agents, numerous antimicrobial delivery systems over the past decades have been developed with the aim to provide new alternatives to the antimicrobial treatment of infections. However, there are few studies that focus on the development of a rational design that is accurate based on a set of theoretical-computational methods that permit the prediction and the understanding of hydrogels regarding their interaction with cationic antimicrobial peptides (cAMPs) as potential sustained and localized delivery nanoplatforms of cAMP. To this aim, we employed docking and Molecular Dynamics simulations (MDs) that allowed us to propose a rational selection of hydrogel candidates based on the propensity to form intermolecular interactions with two types of cAMPs (MP-L and NCP-3a). For the design of the hydrogels, specific building blocks were considered, named monomers (MN), co-monomers (CM), and cross-linkers (CL). These building blocks were ranked by considering the interaction with two peptides (MP-L and NCP-3a) as receptors. The better proposed hydrogel candidates were composed of MN3-CM7-CL1 and MN4-CM5-CL1 termed HG1 and HG2, respectively. The results obtained by MDs show that the biggest differences between the hydrogels are in the CM, where HG2 has two carboxylic acids that allow the forming of greater amounts of hydrogen bonds (HBs) and salt bridges (SBs) with both cAMPs. Therefore, using theoretical-computational methods allowed for the obtaining of the best virtual hydrogel candidates according to affinity with the specific cAMP. In conclusion, this study showed that HG2 is the better candidate for future in vitro or in vivo experiments due to its possible capacity as a depot system and its potential sustained and localized delivery system of cAMP.

Hyaluronic Acid Hydrogel Containing Resveratrol-Loaded Chitosan Nanoparticles as an Adjuvant in Atopic Dermatitis Treatment.

Atopic dermatitis (AD) is a common disease-causing skin inflammation, redness, and irritation, which can eventually result in infection that drastically impacts patient quality of life. Resveratrol (Res) is a natural phytochemical famed for its excellent anti-inflammatory and antioxidant activities. However, it is poorly bioavailable. Thus, a drug delivery system is needed to enhance in vivo bioactivity. Herein, we report the preparation of hyaluronic acid (HA) hydrogels containing resveratrol-loaded chitosan (CS) nanoparticles, their physicochemical analysis, and their potential therapeutic effects in the treatment of AD. Positively charged CS nanoparticles prepared by tripolyphosphate (TPP) gelation showed sizes ranging from 120 to around 500 nm and Res encapsulation efficiency as high as 80%. Embedding the nanoparticles in HA retarded their hydrolytic degradation and also slowed resveratrol release. Resveratrol released from nanoparticle-loaded hydrogel counteracted the oxidative damage induced by ROS generation in TNF-α/INF-γ-treated human keratinocytes (HaCaT) used as an AD in vitro model. Moreover, pre-treatment with Res@gel reduced secretion and gene expression of proinflammatory cytokines in HaCaT cells. The physicochemical analysis and in vitro assay confirmed that the formulated hydrogel could be considered an efficient and sustained resveratrol delivery vector in AD treatment.

Impact of Crosslinking on the Characteristics of Pectin Monolith Cryogels.

In this research, the pectin monoliths were prepared via the sol-gel process through different routes of crosslinking and additional freeze-drying. The crosslinking reaction was induced by the use of calcium ions in aqueous solutions and in alcohol/water solutions. The resulting pectin monoliths obtained by freeze-drying were macroporous with open cells, limited specific surface area, moderate mechanical stability and moderate biodegradation rate. The presence of alcohol in crosslinking solution significantly changed the morphology of final pectin monoliths, which was evidenced by the reduction of their pore size for one order. The specific surface area of pectin monoliths obtained through the calcium-water-alcohol route was 25.7 m2/g, the Young compressive modulus was 0.52 MPa, and the biodegradation rate was 45% after 30 days of immersion in compost media. Considering that pectin can be obtained from food waste, and its physical properties could be tailored by different crosslinking routes, the pectin monoliths could find wide application in the pharmaceutical, agricultural, medical and food industries, providing sustainable development concepts.

Comparative Study of Three Dyes' Adsorption onto Activated Carbon from Chenopodium quinoa Willd and Quillaja saponaria.

The present study shows porous activated carbon obtained from Chenopodium quinoa Willd and Quillaja saponaria and their use as potential adsorbents to remove three types of dyes from aqueous solutions. The adsorption results were compared with commercial charcoal to check their efficiency. All porous carbon materials were activated using carbon dioxide and steam and fully characterized. Moreover, the steam-activated samples exhibited a high total pore volume with a BET surface area of around 800 m2 g−1. Batch adsorption experiments showed that commercial charcoal is the charcoal that offered the best adsorption efficiency for tartrazine and sunset yellow FCF. However, in the case of crystal violet, all activated carbons obtained from Chenopodium quinoa Willd and Quillaja saponaria showed the best captures, outperforming commercial charcoal. Molecular dockings of the dyes on the commercial charcoal surface were performed using AutoDock Vina. The kinetic results of the three isotherm's models for the present data follow the order: Langmuir~Freundlich > Temkin.

Sulfated Polysaccharide Extracted from the Green Algae Codium bernabei: Physicochemical Characterization and Antioxidant, Anticoagulant and Antitumor Activity.

Codium bernabei is a green alga that grows on Chilean coasts. The composition of its structural polysaccharides is still unknown. Hence, the aim of this work is to isolate and characterize the hot water extracted polysaccharide fractions. For this purpose, the water extracts were further precipitated in alcohol (TPs) and acid media (APs), respectively. Both fractions were characterized using different physicochemical techniques such as GC-MS, GPC, FTIR, TGA, and SEM. It is confirmed that the extracted fractions are mainly made of sulfated galactan unit, with a degree of sulfation of 19.3% (TPs) and 17.4% (ATs) and a protein content of 3.5% in APs and 15.6% in TPs. Other neutral sugars such as xylose, glucose, galactose, fucose, mannose, and arabinose were found in a molar ratio (0.05:0.6:1.0:0.02:0.14:0.11) for TPs and (0.05:0.31:1.0:0.03:0.1:0.13) for ATs. The molecular weight of the polysaccharide samples was lower than 20 kDa. Both polysaccharides were thermally stable (Tonset > 190 °C) and showed antioxidant activity according to the ABTS•+ and DPPH tests, where TPs fractions had higher scavenging activity (35%) compared to the APs fractions. The PT and APTTS assays were used to measure the anticoagulant activity of the polysaccharide fractions. In general, the PT activity of the TPs and APs was not different from normal plasma values. The exception was the TPs treatment at 1000 µg mL−1 concentration. The APTTS test revealed that clotting time for both polysaccharides was prolonged regarding normal values at 1000 µg mL−1. Finally, the antitumor test in colorectal carcinoma (HTC-116) cell line, breast cancer (MCF-7) and human leukemia (HL-60) cell lines showed the cytotoxic effect of TPs and APs. Those results suggest the potential biotechnological application of sulfate galactan polysaccharides isolated from a Chilean marine resource.

Optimization and Characterization of a Novel Exopolysaccharide from Bacillus haynesii CamB6 for Food Applications.

Extremophilic microorganisms often produce novel bioactive compounds to survive under harsh environmental conditions. Exopolysaccharides (EPSs), a constitutive part of bacterial biofilm, are functional biopolymers that act as a protecting sheath to the extremophilic bacteria and are of high industrial value. In this study, we elucidate a new EPS produced by thermophilic Bacillus haynesii CamB6 from a slightly acidic (pH 5.82) Campanario hot spring (56.4 °C) located in the Central Andean Mountains of Chile. Physicochemical properties of the EPS were characterized by different techniques: Scanning electron microscopy- energy dispersive X-ray spectroscopy (SEM-EDS), Atomic Force Microscopy (AFM), High-Performance Liquid Chromatography (HPLC), Gel permeation chromatography (GPC), Fourier Transform Infrared Spectroscopy (FTIR), 1D and 2D Nuclear Magnetic Resonance (NMR), and Thermogravimetric analysis (TGA). The EPS demonstrated amorphous surface roughness composed of evenly distributed macromolecular lumps. GPC and HPLC analysis showed that the EPS is a low molecular weight heteropolymer composed of mannose (66%), glucose (20%), and galactose (14%). FTIR analysis demonstrated the polysaccharide nature (-OH groups, Acetyl groups, and pyranosic ring structure) and the presence of different glycosidic linkages among sugar residues, which was further confirmed by NMR spectroscopic analyses. Moreover, D-mannose α-(1→2) and α-(1→4) linkages prevail in the CamB6 EPS structure. TGA revealed the high thermal stability (240 °C) of the polysaccharide. The functional properties of the EPS were evaluated for food industry applications, specifically as an antioxidant and for its emulsification, water-holding (WHC), oil-holding (OHC), and flocculation capacities. The results suggest that the study EPS can be a useful additive for the food-processing industry.

Impact of the Hydrolysis and Methanolysis of Bidesmosidic Chenopodium quinoa Saponins on Their Hemolytic Activity.

Saponins are specific metabolites abundantly present in plants and several marine animals. Their high cytotoxicity is associated with their membranolytic properties, i.e., their propensity to disrupt cell membranes upon incorporation. As such, saponins are highly attractive for numerous applications, provided the relation between their molecular structures and their biological activities is understood at the molecular level. In the present investigation, we focused on the bidesmosidic saponins extracted from the quinoa husk, whose saccharidic chains are appended on the aglycone via two different linkages, a glycosidic bond, and an ester function. The later position is sensitive to chemical modifications, such as hydrolysis and methanolysis. We prepared and characterized three sets of saponins using mass spectrometry: (i) bidesmosidic saponins directly extracted from the ground husk, (ii) monodesmosidic saponins with a carboxylic acid group, and (iii) monodesmosidic saponins with a methyl ester function. The impact of the structural modifications on the membranolytic activity of the saponins was assayed based on the determination of their hemolytic activity. The natural bidesmosidic saponins do not present any hemolytic activity even at the highest tested concentration (500 µg·mL-1). Hydrolyzed saponins already degrade erythrocytes at 20 µg·mL-1, whereas 100 µg·mL-1 of transesterified saponins is needed to induce detectable activity. The observation that monodesmosidic saponins, hydrolyzed or transesterified, are much more active against erythrocytes than the bidesmosidic ones confirms that bidesmosidic saponins are likely to be the dormant form of saponins in plants. Additionally, the observation that negatively charged saponins, i.e., the hydrolyzed ones, are more hemolytic than the neutral ones could be related to the red blood cell membrane structure.

Novel Biocomposite Films Based on High Methoxyl Pectin Reinforced with Zeolite Y for Food Packaging Applications.

Pectin is a natural biopolymer with broad applications in the food industry and it is suitable to prepare edible films to prolong food shelf-life. However, the main limitation of pectin-based films is their poor mechanical and barrier properties. Zeolite Y is a hydrophobic clay that can be used as film reinforcement material to improve its physicochemical and mechanical properties. In this work, the influence of high methoxyl citrus and apple pectin on physicochemical properties of biopolymer films modified with zeolite Y (0.05-0.2 wt%) was investigated. The films were characterized by FTIR, TGA, WAXD, mechanical analysis, and water vapor permeability analysis, and a potential film application is presented. The WAXD and FTIR analysis demonstrated that the strongest interaction between pectin chains and zeolite Y occurred when citrus high methylated pectin was used. Adding 0.2 wt% of zeolite Y into citrus high methylated pectin matrix enhanced the tensile strength by 66%, thermal stability by 13%, and water vapor barrier by 54%. In addition, fruit shelf-life test was performed, where strawberries were sealed in film. It was shown that sealed strawberries maintained a better color and healthy appearance than the control treatment after 7 days at 10 °C. This study enabled the development of biocomposite films with improved properties for potential application in food packaging.

Production of Fungal Nanochitosan Using High-Pressure Water Jet System for Biomedical Applications.

In this present work, fungal nanochitosans, with very interesting particle size distribution of 22 µm, were efficiently generated in high-yield production using a high-pressure water jet system (Star Burst System, Sugino, Japan) after 10 passes of mechanical treatment under high pressure. The specific characterization of fungal chitosan nanofibers suspensions in water revealed a high viscosity of 1450 mPa.s and an estimated transparency of 43.5% after 10 passes of fibrillation mechanical treatment. The mechanical characterization of fungal nanochitosan (NC) film are very interesting for medical applications with a Young's modulus (E), a tensile strength (TS), and elongation at break (e%) estimated at 2950 MPa, 50.5 MPa, and 5.5%, respectively. Furthermore, we exhibited that the fungal nanochitosan (NC) film presented very good long-term antioxidant effect (reached 82.4% after 96 h of contact with DPPH radical solution) and very interesting antimicrobial activity when the nanochitosan (NC) fibers are mainly activated as NC-NH3+ form at the surface of the film with 45% reduction and 75% reduction observed for S. aureus (Gram-positive) and E. coli (Gram-negative), respectively, after 6 h of treatment. These promising antimicrobial and antioxidant activities indicated the high potential of valorization toward biomedical applications.

Stress Dependent Biofilm Formation and Bioactive Melanin Pigment Production by a Thermophilic Bacillus Species from Chilean Hot Spring.

Thermophilic bacteria able to survive extreme temperature stress are of great biotechnological interest due to their extracellular production of bioactive molecules as a part of a survival strategy, or by intracellular modifications. In the present study, thermophilic Bacillus haynesii CamB6, isolated from a Chilean hot spring, was studied for the formation of different stress response molecules. The polymeric pigment produced by the bacterial strain was characterized by different physicochemical techniques. On exposure to ranges of temperature (50-60 °C), pH (5.0-7.0), and sources of nitrogen and carbon (1-5 g·L-1), the bacteria responded with a biofilm network formation in a hydrophobic polystyrene surface. Biofilm formation under fed-batch conditions was also statistically validated. The bacteria showed a planktonic pellicle network formation in the presence of induced hypoxia and salinity stress (19.45 g·L-1) under static conditions. Salinity stress also resulted in the intracellular response of brown pigment production. The pigment was structurally and functionally characterized by UV-Vis absorbance and the presence of different characteristic peaks via FTIR analysis (bacterial pyomelanin fingerprints) were assessed. A high thermal stability and TGA profile indicated the brown pigment was a probable pyomelanin candidate. Micropyrolysis (Py-GC/MS) showed that isoprene, pyrrole, benzene, pyridine, and their derivatives were the major components detected. In addition, acetic acid, indole, phenol, and its derivatives were observed. The absence of sulfocompounds in the pyrolyzed products agreed with those reported in the literature for pyomelanin. The pigment surface morphology was analyzed via SEM, and the elemental composition via EDS also demonstrated the similarity of the brown pigment to that of the melanin family. The pyomelanin pigment was observed to be bioactive with promising antioxidant capacity (H2O2, Fe2+) compared to the standard antioxidant molecules. In conclusion, B. haynesii CamB6 demonstrated the formation of several biomolecules as a stress response mechanism that is bioactive, showing its probable biotechnological applications in future.

Polyphenolic Composition and Antioxidant Activity (ORAC, EPR and Cellular) of Different Extracts of Argylia radiata Vitroplants and Natural Roots.

Plant biochemistry studies have increased in recent years due to their potential to improve human health. Argylia radiata is an extremophile plant with an interesting polyphenolic profile. However, its biomass is scarce and occasionally available. Argylia in vitro biomass was obtained from tissue culture and compared with in vivo roots regarding its polyphenolic and flavonoid content. Different solvents were used to prepare extracts from the in vitro tissue of callus and aerial plant organs and in vivo roots. UPLC-MS/MS was used to assess the chemical composition of each extract. ORAC-FL and scavenging of free radicals (DPPH and OH) methods were used to determine the antioxidant capacity of extracts. Furthermore, the biological activity of the extracts was established using the cellular antioxidant activity method. The vitroplants were a good source of polyphenols (25-68 mg GAE/100 g tissue FW), and methanol was the most efficient solvent. Eight polyphenolic compounds were identified, and their antioxidant properties were investigated by different chemical methods with EPR demonstrating its specific scavenging activity against free radicals. All extracts showed cellular dose-dependent antioxidant activity. The methanolic extract of vitroplants showed the highest cellular antioxidant activity (44.6% and 51%) at 1 and 10 µg/mL of extract, respectively. Vitroplants of A. radiata are proposed as a biotechnological product as a source of antioxidant compounds with multiple applications.

Bioactive Pectin-Murta (Ugni molinae T.) Seed Extract Films Reinforced with Chitin Fibers.

This study investigated the biocomposite pectin films enriched with murta (Ugni molinae T.) seed polyphenolic extract and reinforced by chitin nanofiber. The structural, morphological, mechanical, barrier, colorimetric, and antioxidant activity of films were evaluated. The obtained data clearly demonstrated that the addition of murta seed extract and the high load of chitin nanofibers (50%) provided more cohesive and dense morphology of films and improved the mechanical resistance and water vapor barrier in comparison to the control pectin film. The antioxidant activity ranged between 71% and 86%, depending on the film formulation and concentration of chitin nanofibers. The presented results highlight the potential use of chitin nanofibers and murta seed extract in the pectin matrix to be applied in functional food coatings and packaging, as a sustainable solution.

Dextran-Based Edible Coatings to Prolong the Shelf Life of Blueberries.

The development of edible films and coatings in the food packaging industry presents one of the modern strategies for protecting food products and ensuring their freshness and quality during their shelf lives. The application of microbial polysaccharides to the development of food package materials, as an alternative option to the commonly used plastic materials, is both economic and environmentally favorable. New edible films were developed using dextran from lactic acid bacterium Leuconostoc mesenteroides T3, and additionally plasticized by different concentrations of polyglycerol. The best tensile strength of the films was obtained using a formulation that contained 10 wt% of polyglycerol, which corresponded to a value of 4.6 MPa. The most flexible formulation, with elongation at break of 602%, was obtained with 30 wt% of polyglycerol. Water vapor permeability values of the films synthesized in this study were in the range of (3.45-8.81) ∗ 10-12 g/m s Pa. Such low values indicated that they could be efficient in preventing fruit from drying out during storage. Thus, the film formulations were used to coat blueberries in order to assess their quality during a storage time of 21 days at 8 °C. The results showed that dextran/polyglycerol films could be efficient in extending the shelf life of blueberries, which was evidenced by lower weight loss and total sugar solids values, as well as a delay in titratable acidity, in comparison to the uncoated blueberries.

Use of Poly(vinyl alcohol)-Malic Acid (CLHPMA) Hydrogels and Chitosan Coated Calcium Alginate (CCCA) Microparticles as Potential Sorbent Phases for the Extraction and Quantitative Determination of Pesticides from Aqueous Solutions.

Pesticides are used worldwide to increase crop yields in agriculture. However, their toxicity and accumulation capacity can make them toxic to the environment, animals and humans. In the case of workers chronically exposed to these substances, they must be sampled continuously, so urine is an excellent option. In this sense, this study proposes to use poly(vinyl alcohol)-malic acid hydrogels, and chitosan-coated calcium alginate as new sorbent phases to be used in pesticide determination processes in urine. To better understand the behavior of these materials in the capture and desorption process, molecular dynamics simulations (MDS) were used, and desorption experiments were performed, using mechanical agitation, ultrasound, and pH variation in the desorption process, in order to optimize the parameters to obtain better recoveries. Under the optimal experimental conditions, the maximum recoveries were of the order of 11% (CFN), 3% (KCF), 53% (DMT), 18% (MTD) and 35% (MTL). Although the recoveries were not exhaustive, they are a first approximation for the use of these new sorbent phases in the determination of this type of compound in aqueous solutions and urine.