Novel Hydrogel Membranes Based on the Bacterial Polysaccharide FucoPol: Design, Characterization and Biological Properties

FucoPol, a fucose-rich polyanionic polysaccharide, was used for the first time for the preparation of hydrogel membranes (HMs) using Fe³⁺ as a crosslinking agent. This study evaluated the impact of Fe³⁺ and FucoPol concentrations on the HMs' strength. The results show that, above 1.5 g/L, Fe³⁺ concentration had a limited influence on the HMs' strength, and varying the FucoPol concentration had a more significant effect. Three different FucoPol concentrations (1.0, 1.75 and 2.5 wt.%) were combined with Fe³⁺ (1.5 g/L), resulting in HMs with a water content above 97 wt.% and an Fe³⁺ content up to 0.16 wt.%. HMs with lower FucoPol content exhibited a denser porous microstructure as the polymer concentration increased. Moreover, the low polymer content HM presented the highest swelling ratio (22.3 ± 1.8 g/g) and a lower hardness value (32.4 ± 5.8 kPa). However, improved mechanical properties (221.9 ± 10.2 kPa) along with a decrease in the swelling ratio (11.9 ± 1.6 g/g) were obtained for HMs with a higher polymer content. Furthermore, all HMs were non-cytotoxic and revealed anti-inflammatory activity. The incorporation of FucoPol as a structuring agent and bioactive ingredient in the development of HMs opens up new possibilities for its use in tissue engineering, drug delivery and wound care management.

Effect of Olive Pomace Extract Application and Packaging Material on the Preservation of Fresh-Cut Royal Gala Apples

The efficiency of natural olive pomace extracts for enhancing the quality of fresh-cut apples was compared with commercial ascorbic acid and two different packaging films (biodegradable polylactic acid (PLA) and oriented polypropylene (OPP)) were tested. The composition of atmosphere inside the packages, the physicochemical parameters (firmness, weight loss and color), the microbial load, total phenolic content and antioxidant activity of fresh-cut apples were evaluated throughout 12 days of storage at 4 °C. After 12 days of refrigerated storage, a significant decrease in O₂ was promoted in PLA films, and the weight loss of the whole packaging was higher in PLA films (5.4%) than in OPP films (0.2%). Natural olive pomace extracts reduced the load of mesophilic bacteria (3.4 ± 0.1 log CFU/g and 2.4 ± 0.1 log CFU/g for OPP and PLA films, respectively) and filamentous fungi (3.3 ± 0.1 log CFU/g and 2.44 ± 0.05 log CFU/g for OPP and PLA films, respectively) growth in fresh-cut apples after five days of storage at 4 °C, and no detection of coliforms was verified throughout the 12 days of storage. In general, the olive pomace extract preserved or improved the total phenolic index and antioxidant potential of the fruit, without significant changes in their firmness. Moreover, this extract seemed to be more effective when combined with the biodegradable PLA film packaging. This work can contribute to the availability of effective natural food additives, the sustainability of the olive oil industries and the reduction of environmental impact. It can also be useful in meeting the food industries requirements to develop new functional food products.

Recovery and Purification of Cutin from Tomato By-Products for Application in Hydrophobic Films

Tomato pomace is a low-cost, renewable resource that has been studied for the extraction of the biopolyester cutin, which is mainly composed of long-chain hydroxy fatty acids. These are excellent building blocks to produce new hydrophobic biopolymers. In this work, the monomers of cutin were extracted and isolated from tomato pomace and utilized to produce cutin-based films. Several strategies for the depolymerization and isolation of monomeric cutin were explored. Strategies differed in the state of the raw material at the beginning of the extraction process, the existence of a tomato peel dewaxing step, the type of solvent used, the type of alkaline hydrolysis, and the isolation method of cutin monomers. These strategies enabled the production of extracts enriched in fatty acids (16-hydroxyhexadecanoic, hexadecanedioic, stearic, and linoleic, among others). Cutin and chitosan-based films were successfully cast from cutin extracts and commercial chitosan. Films were characterized regarding their thickness (0.103 ± 0.004 mm and 0.106 ± 0.005 mm), color, surface morphology, water contact angle (93.37 ± 0.31° and 95.15 ± 0.53°), and water vapor permeability ((3.84 ± 0.39) × 10^-11 mol·m/m²·s·Pa and (4.91 ± 1.33) × 10^-11 mol·m/m²·s·Pa). Cutin and chitosan-based films showed great potential to be used in food packaging and provide an application for tomato processing waste.

Chitin-Glucan Complex Hydrogels: Physical-Chemical Characterization, Stability, In Vitro Drug Permeation, and Biological Assessment in Primary Cells

Chitin-glucan complex (CGC) hydrogels were fabricated by coagulation of the biopolymer from an aqueous alkaline solution, and their morphology, swelling behavior, mechanical, rheological, and biological properties were studied. In addition, their in vitro drug loading/release ability and permeation through mimic-skin artificial membranes (Strat-M) were assessed. The CGC hydrogels prepared from 4 and 6 wt% CGC suspensions (Na5₁*⁴ and Na5₁*⁶ hydrogels, respectively) had polymer contents of 2.40 ± 0.15 and 3.09 ± 0.22 wt%, respectively, and displayed a highly porous microstructure, characterized by compressive moduli of 39.36 and 47.30 kPa and storage moduli of 523.20 and 7012.25 Pa, respectively. Both hydrogels had a spontaneous and almost immediate swelling in aqueous media, and a high-water retention capacity (>80%), after 30 min incubation at 37 °C. Nevertheless, the Na5₁*⁴ hydrogels had higher fatigue resistance and slightly higher-water retention capacity. These hydrogels were loaded with caffeine, ibuprofen, diclofenac, or salicylic acid, reaching entrapment efficiency values ranging between 13.11 ± 0.49% for caffeine, and 15.15 ± 1.54% for salicylic acid. Similar release profiles in PBS were observed for all tested APIs, comprising an initial fast release followed by a steady slower release. In vitro permeation experiments through Strat-M membranes using Franz diffusion cells showed considerably higher permeation fluxes for caffeine (33.09 µg/cm²/h) and salicylic acid (19.53 µg/cm²/h), compared to ibuprofen sodium and diclofenac sodium (4.26 and 0.44 µg/cm²/h, respectively). Analysis in normal human dermal fibroblasts revealed that CGC hydrogels have no major effects on the viability, migration ability, and morphology of the cells. Given their demonstrated features, CGC hydrogels are very promising structures, displaying tunable physical properties, which support their future development into novel transdermal drug delivery platforms.

Characterisation of Films Based on Exopolysaccharides from Alteromonas Strains Isolated from French Polynesia Marine Environments

This work assessed the film-forming capacity of exopolysaccharides (EPS) produced by six Alteromonas strains recently isolated from different marine environments in French Polynesia atolls. The films were transparent and resulted in small colour alterations when applied over a coloured surface (ΔEab below 12.6 in the five different colours tested). Moreover, scanning electron microscopy showed that the EPS films were dense and compact, with a smooth surface. High water vapour permeabilities were observed (2.7-6.1 × 10-11 mol m-1 s-1 Pa-1), which are characteristic of hydrophilic polysaccharide films. The films were also characterised in terms of barrier properties to oxygen and carbon dioxide. Interestingly, different behaviours in terms of their mechanical properties under tensile tests were observed: three of the EPS films were ductile with high elongation at break (ε) (35.6-47.0%), low tensile strength at break (Ꞇ) (4.55-11.7 MPa) and low Young's modulus (εm) (10-93 MPa), whereas the other three were stiffer and more resistant with a higher Ꞇ (16.6-23.6 MPa), lower ε (2.80-5.58%), and higher εm (597-1100 MPa). These properties demonstrate the potential of Alteromonas sp. EPS films to be applied in different areas such as biomedicine, pharmaceuticals, or food packaging.

Storage Stability and In Vitro Bioaccessibility of Microencapsulated Tomato (Solanum Lycopersicum L.) Pomace Extract

Tomato pomace is rich in carotenoids (mainly lycopene), which are related to important bioactive properties. In general, carotenoids are known to react easily under environmental conditions, which may create a barrier in producing stable functional components for food. This work intended to evaluate the storage stability and in vitro release of lycopene from encapsulated tomato pomace extract, and its bioaccessibility when encapsulates were incorporated in yogurt. Microencapsulation assays were carried out with tomato pomace extract as the core material and arabic gum or inulin (10 and 20 wt%) as wall materials by spray drying (160 and 200 °C). The storage stability results indicate that lycopene degradation was highly influenced by the presence of oxygen and light, even when encapsulated. In vitro release studies revealed that 63% of encapsulated lycopene was released from the arabic gum particles in simulated gastric fluid, whereas for the inulin particles, the release was only around 13%. The feed composition with 20% inulin showed the best protective ability and the one that enabled releasing the bioactives preferentially in the intestine. The bioaccessibility of the microencapsulated lycopene added to yogurt increased during simulated gastrointestinal digestion as compared to the microencapsulated lycopene alone. We anticipate a high potential for the inulin microparticles containing lycopene to be used in functional food formulations.

Poly(ethylene glycol) Diacrylate Iongel Membranes Reinforced with Nanoclays for CO2 Separation

Despite the fact that iongels are very attractive materials for gas separation membranes, they often show mechanical stability issues mainly due to the high ionic liquid (IL) content (≥60 wt%) needed to achieve high gas separation performances. This work investigates a strategy to improve the mechanical properties of iongel membranes, which consists in the incorporation of montmorillonite (MMT) nanoclay, from 0.2 to 7.5 wt%, into a cross-linked poly(ethylene glycol) diacrylate (PEGDA) network containing 60 wt% of the IL 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C2mim][TFSI]). The iongels were prepared by a simple one-pot method using ultraviolet (UV) initiated polymerization of poly(ethylene glycol) diacrylate (PEGDA) and characterized by several techniques to assess their physico-chemical properties. The thermal stability of the iongels was influenced by the addition of higher MMT contents (>5 wt%). It was possible to improve both puncture strength and elongation at break with MMT contents up to 1 wt%. Furthermore, the highest ideal gas selectivities were achieved for iongels containing 0.5 wt% MMT, while the highest CO2 permeability was observed at 7.5 wt% MMT content, due to an increase in diffusivity. Remarkably, this strategy allowed for the preparation and gas permeation of self-standing iongel containing 80 wt% IL, which had not been possible up until now.

Development of cellulose-based polymeric structures using dual functional ionic liquids

Carboxylate ionic liquids (ILs) combining benzethonium (BE) and didecyldimethylammonium (DDA) as cations have been explored to be used for the first time as dual functional solvents for microcrystalline cellulose (MCC) dissolution and, subsequently development of polymeric structures. Considering that some ILs can remain in the polymeric structures after phase inversion, these ILs can offer advantages such as antibacterial/antimicrobial response and ability to disrupt H-bonds. In this context, all tested ILs have been able to dissolve MCC up to a concentration of 4% (w/w), resulting in different polymeric structures, such as gel-like or films, depending on the type of IL and the ratio between MCC and IL. Furthermore, FTIR spectroscopy showed that some IL remains in the polymeric structures, which can enhance their application in the biomedical field.

Characterization and Biotechnological Potential of Extracellular Polysaccharides Synthesized by Alteromonas Strains Isolated from French Polynesia Marine Environments

Marine environments comprise almost three quarters of Earth's surface, representing the largest ecosystem of our planet. The vast ecological and metabolic diversity found in marine microorganisms suggest that these marine resources have a huge potential as sources of novel commercially appealing biomolecules, such as exopolysaccharides (EPS). Six Alteromonas strains from different marine environments in French Polynesia atolls were selected for EPS extraction. All the EPS were heteropolysaccharides composed of different monomers, including neutral monosaccharides (glucose, galactose, and mannose, rhamnose and fucose), and uronic acids (glucuronic acid and galacturonic acid), which accounted for up to 45.5 mol% of the EPS compositions. Non-carbohydrate substituents, such as acetyl (0.5-2.1 wt%), pyruvyl (0.2-4.9 wt%), succinyl (1-1.8 wt%), and sulfate (1.98-3.43 wt%); and few peptides (1.72-6.77 wt%) were also detected. Thermal analysis demonstrated that the EPS had a degradation temperature above 260 °C, and high char yields (32-53%). Studies on EPS functional properties revealed that they produce viscous aqueous solutions with a shear thinning behavior and could form strong gels in two distinct ways: by the addition of Fe2+, or in the presence of Mg2+, Cu2+, or Ca2+ under alkaline conditions. Thus, these EPS could be versatile materials for different applications.

Development of a Cryoprotective Formula Based on the Fucose-Containing Polysaccharide FucoPol

This study reports the performance of the polysaccharide FucoPol as an enhancer of cryoprotective formulations. FucoPol at a concentration of 0.25% (w/v) was added to several normothermic Dulbecco-derived solutions and hypothermic Euro-Collins, Custodiol-HTK, and Unisol-CV media, substituting some constituents in the latter class to develop FucoPol-based formulations that were tested for their ability to cryopreserve Vero cells. Supplementation yielded post-thaw cell recovery enhancements of at least 70% and averaged at 82%. The FucoPol-supplemented formulations Dulbecco(+)^+FP and Unisol-CV_S3 achieved cell viabilities capable of competing with the commercial cryogenic formula CryoStor CS5. Particularly in Unisol-CV_S3, mannitol, glucose, gluconate, and dextran were all substituted by 0.25% FucoPol, and still, a similar viability was achieved. Multiparametric correlation clustering showed that FucoPol cryoprotection synergizes best with K⁺, Ca²⁺, and Cl^- in its microenvironment. Component substitution analysis demonstrated that FucoPol acts consistently as a cryoprotectant, an impermeant, and a colloidal stabilizer, providing a combined alternative to glucose, mannitol, gluconate, and dextran, thus highlighting its potential in the development of high-performing cryoprotective formulas.

Composite Coatings of Chitosan and Alginate Emulsions with Olive Oil to Enhance Postharvest Quality and Shelf Life of Fresh Figs (Ficus carica L. cv. 'Pingo De Mel')

Fresh figs are very appreciated and have been associated with health benefits. However, these fruits are highly perishable. In this study, edible coatings were studied envisaging their positive effect in enhancing figs' shelf-life. Fig fruits cv. 'Pingo de mel' were harvested at commercial ripening stage and single emulsion-based coatings, composed of chitosan + olive oil and alginate + olive oil, were applied. After coatings application by dipping each fruit in the emulsion-based solutions at 4 °C and drying, the coated fruits were sprayed with crosslinking solutions (6% tripolyphosphate and 1% calcium chloride for chitosan and alginate-based coatings, respectively). Then, were maintained at 4 °C and analyzed after 1, 7, 14 and 19 days of storage. After each time interval, fruits were further maintained at 25 °C for 2 days. The results have shown that coatings were effective on delaying fungal decay and postharvest ripening indicators (respiration rate, mass loss, softening and total soluble solids/titratable acidity ratio). The results foresee a fruits' shelf life between 14 and 19 days under refrigeration at 4 °C that may be followed up to 2 days at ambient temperature, higher than that estimated for uncoated fruits (less than 14 days at 4 °C plus to 2 days at ambient temperature).

Rendering Banana Plant Residues into a Potentially Commercial Byproduct by Doping Cellulose Films with Phenolic Compounds

This study seeks to render residues from banana plants into a useful byproduct with possible applications in wound dressings and food packaging. Films based on cellulose extracted from banana plant pseudostem and doped with phenolic compounds extracted from banana plant leaves were developed. The phenolic compounds were extracted using batch solid-liquid and Soxhlet methods, with different drying temperatures and periods of time. The total phenolic content and antioxidant activity were quantified. The optimum values were obtained using a three-day period batch-solid extraction at 40 °C (791.74 ± 43.75 mg/L). SEM analysis indicates that the pseudostem (PS) films have a porous structure, as opposed to hydroxyethyl cellulose (HEC) films which presented a homogeneous and dense surface. Mechanical properties confirmed the poor robustness of PS films. By contrast HEC films manifested improved tensile strength at low levels of water activity. FTIR spectroscopy reinforced the need to improve the cellulose extraction process, the success of lignin and hemicellulose removal, and the presence of phenolic compounds. XRD, TGA and contact angle analysis showed similar results for both films, with an amorphous structure, thermal stability and hydrophilic behavior.

Proinflammatory circulating markers: new players for evaluating asymptomatic acute cardiovascular toxicity in breast cancer treatment

PURPOSE

This study aimed to evaluate markers of cardiac damage (total CK, CKMB and CRP), inflammatory markers (free iron, homocysteine and TNF-α) as well as lipidogram in breast cancer patients undergoing acute cycles of doxorubicin (DOX), paclitaxel (PTX) or trastuzumab (TZ) and to verify if there is an association between these markers and the toxicity of the chemotherapeutic treatment. Methods: Included in the study were 120 breast cancer patients and 50 healthy controls. All analyzes were performed on automated systems. For the statistical analysis, each group was compared with the controls according to their normality by Student's t-test and Mann-Whitney test. Results: Our results showed that DOX treatment led to increased hsCRP (4.80 ± 1.23 mg/dL, p = 0.0005), triglycerides (187.6 ± 25.06, p = 0.0231), TNF-α (42.31 ± 17.96 pg/mL, p = 0.01) and Fe levels (138.8 ± 18.6 μg/dL, p = 0.0193). In the meantime, PTX induced changes in CK-MB (8.78 ± 4.2 U/L, p = 0.0361), hsCRP (7.12 ± 1.87 mg/dL, p = 0.0006), cholesterol (201.7 ± 19.54, p = 0.05), triglycerides (201.7 ± 19.54, p = 0.0277), TNF-α (38.27 ± 9.12 pg/mL, p = 0.023), homocysteine (10.95 ± 0, 86 μmol/L, p = 0.005), and free iron (113 ± 18 6 μg/dL, p = 0.045) while TZ augmented CK-MB (6.9 ± 1.97 U/L, p < 0.00), hsPCR (3.12 ± 0.68 mg/dL, p = 0.095), cholesterol (218.3 ± 16.79, p = 0.0317), triglycerides (218.3 ± 16.79, p = 0.0127), TNF-α (89.6 ± 12.11, p = 0.032), homocysteine (9.95 ± 1.15 μmol/L, p = 0.0396), free iron (120.5 ± 4.64 μg/dl, p = 0.0058) as well. Conclusions: Our data demonstrated the existence of a proinflammatory net triggered by breast cancer chemotherapy that could increase cardiomyocytes permeability and allow the leakage of circulating proteins as CK-MB and induce the production of hsCRP.

Production of medium-chain-length polyhydroxyalkanoates by Pseudomonas chlororaphis subsp. aurantiaca: Cultivation on fruit pulp waste and polymer characterization

Pseudomonas chlororaphis subsp. aurantiaca DSM 19603 was cultivated on apple pulp, a glucose- and fructose-rich waste generated during juice production, to produce medium-chain length polyhydroxyalkanoates. A cell dry mass of 8.74 ± 0.20 g/L, with a polymer content of 49.25 ± 4.08% were attained. The produced biopolymer was composed of 42.7 ± 0.1 mol% 3-hydroxydecanoate, 17.9 ± 1.0 mol% 3-hydroxyoctanoate, 14.5 ± 1.1 mol% 3-hydroxybutyrate, 11.1 ± 0.6 mol% 3-hydroxytetradecanoate, 10.1 ± 0.5 mol% 3-hydroxydodecanoate and 3.7 ± 0.2 mol% 3-hydroxyhexanoate. It presented low glass transition and melting temperatures (-40.9 ± 0.7 °C and 42.0 ± 0.1 °C, respectively), and a degradation temperature of 300.0 ± 0.1 °C, coupled to a low crystallinity index (12.7 ± 2.7%), a molecular weight (Mw) of 1.34 × 10⁵ ± 0.18 × 10⁵ Da and a polydispersity index of 2.70 ± 0.03. The biopolymer's films were dense and had a smooth surface, as demonstrated by Scanning Electron Microscopy. They presented a tension at break of 5.21 ± 1.09 MPa, together with an elongation of 400.5 ± 55.8% and an associated Young modulus of 4.86 ± 1.49 MPa, under tensile tests. These attractive filming properties of this biopolymer could potentially be valorised in several areas such as the fine chemicals industry, biomedicine, pharmaceuticals, or food packaging.

Application of Edible Alginate Films with Pineapple Peel Active Compounds on Beef Meat Preservation

Alginate-based edible films containing natural antioxidants from pineapple peel were applied in the microbial spoilage control, color preservation, and barrier to lipid oxidation of beef steaks under storage at 4 °C for five days. Different stabilization methods of pineapple peel compounds were used before incorporation into alginate films, including extracted compounds with an hydroalcoholic solvent encapsulated in microparticles, microparticles produced by spray-drying pineapple peel juice, and particles obtained by milling freeze dried pineapple peel. Bioactive films exhibited higher antioxidant activity (between 0.15 µmol to 0.35 µmol FeSO4.7H2O/g dried film) than the alginate film without these compounds (0.02 µmol FeSO4.7H2O/g dried film). Results showed that control films without active compounds had no significant effect on decreasing the microbial load of aerobic mesophilic and Pseudomonas spp., while the films containing encapsulated hydroalcoholic extract showed a significant inhibitory effect on microbial growth of meat at two days of storage. Alginate films containing peel encapsulated extract were effective for maintaining the color hue and intensity of red beef meat samples. Pineapple peel antioxidants have the potential to retard lipid oxidation in meat samples, and the possibility of incorporation of a higher amount of pineapple peel bioactive compounds in the films should be investigated.

Low Temperature Dissolution of Yeast Chitin-Glucan Complex and Characterization of the Regenerated Polymer

Chitin-glucan complex (CGC) is a copolymer composed of chitin and glucan moieties extracted from the cell-walls of several yeasts and fungi. Despite its proven valuable properties, that include antibacterial, antioxidant and anticancer activity, the utilization of CGC in many applications is hindered by its insolubility in water and most solvents. In this study, NaOH/urea solvent systems were used for the first time for solubilization of CGC extracted from the yeast Komagataella pastoris. Different NaOH/urea ratios (6:8, 8:4 and 11:4 (w/w), respectively) were used to obtain aqueous solutions using a freeze/thaw procedure. There was an overall solubilization of 63-68%, with the highest solubilization rate obtained for the highest tested urea concentration (8 wt%). The regenerated polymer, obtained by dialysis of the alkali solutions followed by lyophilization, formed porous macrostructures characterized by a chemical composition similar to that of the starting co-polymer, although the acetylation degree decreased from 61.3% to 33.9-50.6%, indicating that chitin was converted into chitosan, yielding chitosan-glucan complex (ChGC). Consistent with this, there was a reduction of the crystallinity index and thermal degradation temperature. Given these results, this study reports a simple and green procedure to solubilize CGC and obtain aqueous ChGC solutions that can be processed as novel biomaterials.

Demonstration of the ability of the bacterial polysaccharide FucoPol to flocculate kaolin suspensions

In this study, the flocculation properties of FucoPol, a bacterial extracellular polysaccharide, were investigated. FucoPol is a high molecular weight polymer and negatively charged due to the presence of glucuronic acid and the acyl groups succinyl and pyruvyl. High flocculation rate values (>70%) were achieved with a low bioflocculant dosage of 1 mg/L, for pH values in the range 3-5 and temperature within 15-20°C. The bioflocculant was also shown to be stable after freezing/thawing and heating up to 100°C. Given the polymer's anionic character, the size of flocs formed and their surface profile, bridging seems to be the main flocculation mechanism of FucoPol. This study demonstrated that FucoPol is a promising natural, biodegradable and biocompatible alternative to the currently used synthetic or inorganic hazardous products, with potential to be used as a novel flocculation agent in several applications, such as water treatment, food or mining. Further studies will involve evaluating the reduction of cation dosage on flocculation efficiency, as well as testing the applicability of FucoPol to flocculate different types of suspended solids, such as, for example, activated carbons, soil solids or yeast cells.

Novel hydrogels based on yeast chitin-glucan complex: Characterization and safety assessment

Chitin-glucan complex (CGC) was used for the first time for the preparation of hydrogels. Alkali solvent systems, NaOH and KOH solutions, either at 1 or 5 mol/L, were used for CGC dissolution using a freeze-thaw procedure (freezing at -20 °C and thawing at room temperature; four cycles). The CGC solutions thus obtained were subjected to dialysis that induced the spontaneous gelation of the biopolymer, yielding translucid hydrogels with a yellowish coloration. Although all CGC hydrogels exhibited porous microstructures, high water content (above 97%) and good mechanical properties, their morphology, viscoelastic properties and texture were influenced by the type of solvent system used for CGC dissolution, as well as by their ionic strength. The K-based hydrogels presented a less compact network with larger pores and exhibited lower elastic properties. The Na-based hydrogels, on the other hand, exhibited a denser structure with smaller pores and a stiffer gel structure. These results show that it is possible to prepare CGC hydrogels with differing characteristics that can be suitable for different applications. Furthermore, all hydrogels were non-cytotoxic towards L929 fibroblasts and HaCaT keratinocytes. This study demonstrates CGC can be used to prepare biocompatible hydrogels with properties render them promising biomaterials.

Antioxidants of Natural Plant Origins: From Sources to Food Industry Applications

In recent years, great interest has been focused on using natural antioxidants in food products, due to studies indicating possible adverse effects that may be related to the consumption of synthetic antioxidants. A variety of plant materials are known to be natural sources of antioxidants, such as herbs, spices, seeds, fruits and vegetables. The interest in these natural components is not only due to their biological value, but also to their economic impact, as most of them may be extracted from food by-products and under-exploited plant species. This article provides an overview of current knowledge on natural antioxidants: their sources, extraction methods and stabilization processes. In addition, recent studies on their applications in the food industry are also addressed; namely, as preservatives in different food products and in active films for packaging purposes and edible coatings.

Using a bacterial fucose-rich polysaccharide as encapsulation material of bioactive compounds

The potential of a bacterial exopolysaccharide named FucoPol, produced by the bacterium Enterobacter A47, as encapsulation matrix was explored. Spherical capsules with a smooth surface were produced by spray drying. The obtained microcapsules had average diameters ranging from 0.5 to 26.7μm and presented thin walls (thickness from 222 to 1094nm). The capsules were loaded with two bioactive compounds: gallic acid (GA) and oregano essential oil (OEO). Both bioactive materials were encapsulated in FucoPol particles, retaining their antioxidant activity after the drying process. Release studies showed that GA release in simulated gastric and intestinal fluids was faster than that of OEO, envisaging that the latter had established stronger interactions with the polymer matrix. These results suggest that FucoPol has a good potential for use as encapsulating material of bioactive compounds for application in several areas, including food, cosmetic or pharmaceutical products.

Polysaccharide-Based Membranes in Food Packaging Applications

Plastic packaging is essential nowadays. However, the huge environmental problem caused by landfill disposal of non-biodegradable polymers in the end of life has to be minimized and preferentially eliminated. The solution may rely on the use of biopolymers, in particular polysaccharides. These macromolecules with film-forming properties are able to produce attracting biodegradable materials, possibly applicable in food packaging. Despite all advantages of using polysaccharides obtained from different sources, some drawbacks, mostly related to their low resistance to water, mechanical performance and price, have hindered their wider use and commercialization. Nevertheless, with increasing attention and research on this field, it has been possible to trace some strategies to overcome the problems and recognize solutions. This review summarizes some of the most used polysaccharides in food packaging applications.

Production of polyhydroxyalkanoates from spent coffee grounds oil obtained by supercritical fluid extraction technology

Spent coffee grounds (SCG) oil was obtained by supercritical carbon dioxide (scCO2) extraction in a pilot plant apparatus, with an oil extraction yield of 90% at a 35kgkg(-1) CO2/SCG ratio. Cupriavidus necator DSM 428 was cultivated in 2L bioreactor using extracted SCG oil as sole carbon source for production of polyhydroxyalkanoates. The culture reached a cell dry weight of 16.7gL(-1) with a polymer content of 78.4% (w/w). The volumetric polymer productivity and oil yield were 4.7gL(-1)day(-1) and 0.77gg(-1), respectively. The polymer produced was a homopolymer of 3-hydroxybutyrate with an average molecular weight of 2.34×10(5) and a polydispersity index of 1.2. The polymer exhibited brittle behaviour, with very low elongation at break (1.3%), tensile strength at break of 16MPa and Young's Modulus of 1.0GPa. Results show that SCG can be a bioresource for polyhydroxyalkanoates production with interesting properties.

Study of the interactive effect of temperature and pH on exopolysaccharide production by Enterobacter A47 using multivariate statistical analysis

Enterobacter A47 synthesizes fucose-containing exopolysaccharides (EPS). Maximum EPS production (>7.00 g L(-1)) was obtained for temperature and pH within 25-35°C and 6.0-8.0, respectively. Under these conditions, the polymers contained over 30% fucose. Glucose, galactose, and glucuronic acid contents were about 28%, 25%, and 10%, respectively, and the total acyl groups content was about 20 wt.%. The average molecular weight (Mw) was around 4.0 × 10(6). Outside the optimal temperature and pH ranges, fucose, galactose and glucuronic acid, and the total acyl group contents were reduced, while the glucose content increased, new monomers (rhamnose and glucosamine) were detected, and the Mw increased to ≥ 1.10 × 10(7). This study revealed the ability of Enterobacter A47 to synthesize different heteropolysaccharides as a function of pH and temperature, a feature that can be exploited to obtain tailored polymer composition. Moreover, the production of high fucose content EPS was stable for wide pH and temperature ranges, which is important for the envisaged industrial development of the bioprocess.

Agar extraction from integrated multitrophic aquacultured Gracilaria vermiculophylla: evaluation of a microwave-assisted process using response surface methodology

Microwave-assisted extraction (MAE) of agar from Gracilaria vermiculophylla, produced in an integrated multitrophic aquaculture (IMTA) system, from Ria de Aveiro (northwestern Portugal), was tested and optimized using response surface methodology. The influence of the MAE operational parameters (extraction time, temperature, solvent volume and stirring speed) on the physical and chemical properties of agar (yield, gel strength, gelling and melting temperatures, as well as, sulphate and 3,6-anhydro-L-galactose contents) was evaluated in a 2(4) orthogonal composite design. The quality of the extracted agar compared favorably with the attained using traditional extraction (2 h at 85 degrees Celsius) while reducing drastically extraction time, solvent consumption and waste disposal requirements. Agar MAE optimum results were: an yield of 14.4 + or - 0.4%, a gel strength of 1331 + or - 51 g/cm(2), 40.7 + or - 0.2 degrees Celsius gelling temperature, 93.1 + or - 0.5 degrees Celsius melting temperature, 1.73 + or - 0.13% sulfate content and 39.4 + or - 0.3% 3,6-anhydro-L-galactose content. Furthermore, this study suggests the feasibility of the exploitation of G. vermiculophylla grew in IMTA systems for agar production.