Polysaccharide Films Research Articles

Physical, Mechanical and Biological Properties of Phenolic Acid-Grafted Soluble Soybean Polysaccharide Films.

Three kinds of phenolic acid-grafted soluble soybean polysaccharide (SSPS) with similar grafting ratios were prepared, and their structure was characterized by FT-IR, UV-vis and 1 H NMR. The impact of phenolic acid on the antioxidant activity of SSPS was evaluated. Then, films were prepared by using phenolic acid-grafted SSPS. The physical, mechanical and biological performances of phenolic acid-grafted SSPS films were further investigated. The results indicated that an ester linkage was formed between the SSPS and phenolic acid. The grafting ratio of para-hydroxybenzoic acid, protocatechuic acid and gallic acid-grafted SSPS was 29.45, 31.76 and 30.74 mg/g, respectively. Phenolic acid endowed SSPS with improved antioxidant properties. Gallic acid (GA)-grafted SSPS possessed the best DPPH radical scavenging ability and reducing power, which may be related to the three phenolic hydroxyl groups in GA. Phenolic acid-grafted SSPS films showed increased moisture content and decreased water solubility compared to SSPS film. The phenolic acid-g-SSPS decreased the mechanical properties but enhanced the water vapor barrier property, and antioxidant and antibacterial properties of SSPS film. Meanwhile, the para-hydroxybenzoic acid-grafted SSPS film showed the lowest water vapor permeability (3.70 × 10-7 g mm/h cm2 Pa), and the GA-grafted SSPS film exhibited the best antioxidant and antibacterial activities.

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.

Effect of synergism between sodium alginate and xanthan gum on characteristics of composite film and gloss of areca nut coating

In this study, two polysaccharides of sodium alginate (SA) and xanthan gum (XG) were compounded in proportions of 100:0, 75:25, 50:50, 25:75, 0:100 with 1% total mass concentration and then coated on areca nuts. The effects of their synergistic interactions on the optical appearance of the edible coating were investigated for the first time. Areca nuts coated by 50:50 SA-XG presented the highest gloss (2.69 GU) and maximum spreading coefficient (−33.95 mN/m), indicating the improved wettability of the coating solution on the fruit's surface. The polarized light microscopy exhibited the unique birefringence phenomenon caused by the liquid crystal state, resulting in the better optical properties of the coating. UV–vis transmittance, Fourier transform infrared, and scanning electron microscopy indicated the good compatibility of SA and XG. The SA-XG film was more compactly arranged and had a denser microstructure due to hydrogen bonding. Additionally, the SA-XG combination improved the mechanical properties and water resistance compared to a single polysaccharide films and enhanced the water retention properties for the areca nut coating. Therefore, the SA-XG combination is promising to prepare edible films with improved optical properties for areca nuts.

Intelligent films of marine polysaccharides and purple cauliflower extract for food packaging and spoilage monitoring

In this study, metalloanthocyanin-inspired, biodegradable packaging films were developed by incorporating purple cauliflower extracted (PCE) anthocyanins into alginate (AL)/carboxymethyl chitosan (CCS) hybrid polymer matrices based on complexation of metal ions with these marine polysaccharides and anthocyanins. PCE anthocyanins-incorporated AL/CCS films were further modified with fucoidan (FD) because this sulfated polysaccharide can form strong interactions with anthocyanins. Metals-involved complexation (Ca2+ and Zn2+-crosslinked films) improved the mechanical strength and water vapor permeability but reduced the swelling degree of the films. Zn2+-cross-linked films exhibited significantly higher antibacterial activity than did pristine (non-crosslinked) and Ca2+-cross-linked films. The metal ion/polysaccharide-involved complexation with anthocyanin reduced the release rate of anthocyanins, increased the storage stability and antioxidant capability, and improved the sensitivity of the colorimetric response of the indicator films for monitoring the freshness of shrimp. The anthocyanin-metal-polysaccharide complex film showed great potential as active and intelligent packaging of food products.

Layer-by-layer self-assembled calcium oxide microcapsules with polysaccharide films for natural gas hydrate exploitation

As a sustainable alternative energy source, the exploitation of natural gas hydrate still faces difficulties in reaching the standard of commercial production. Traditional depressurization, thermal stimulation and increasing the contact area by using horizontal wells have limitations in field test results. A novel in-situ heat supplement method is expected to further improve gas production rate coupled with depressurization. By combining surface modification and covalent layer by layer self-assembly, a polysaccharide coated calcium oxide microcapsule as in-situ heat source in gas hydrate reservoir is proposed in this work. The heat release time was prolonged from 0.21 h to 6.82 h in simulated seawater by alternating the preparation method of calcium oxide microcapsules. The element analysis and structure properties of the polysaccharide film was characterized by scanning electron microscope with energy dispersive spectroscopy. Through particle size distribution and comparing the exothermic properties of different preparation methods, the hydration resistance mechanism of hydrophobic modification and multilayer coatings were revealed. Finally, the methane released rate stimulated by the exothermic reaction of microcapsules was delayed from 38.04 mmol/h to 8.46 mmol/h. The coupling of calcium oxide microcapsules in-situ heat supplement method and depressurization is conducive to improve the efficiency of hydrate exploitation. It explored the resource potential and addressed the challenges in natural gas hydrate exploitation.

Ginger Essential Oil as an Active Addition to Composite Chitosan Films: Development and Characterization.

The recent interest in food biopackaging is showing an increasing trend, especially in the development of antimicrobial coatings and films. The focus of this study is to assess the potential application of ginger (Zingiber officinale) essential oil (GEO) to polysaccharide films based on chitosan (CHf) and their utilization as an active edible packaging. The films were characterized by different instrumental techniques, and data indicated significant differences (p < 0.05) in the chemical composition of the samples. Forty-seven active compounds from ginger rhizomes were identified in the examined essential oil by gas chromatography mass spectrometer (GC-MS). Fourier transforms infrared spectra (FT-IR) confirmed an interaction between the hydroxyl groups of the phenolic compounds of the essential oil and the amine groups of the bioactive matrix, as shown by the peaks at wavenumbers 1639 cm−1 and 1558 cm−1. X-ray diffraction data suggested a lower crystallinity in the CHf due to the addition of GEO. Differential scanning calorimetric (DSC) analysis revealed that the CHf possessed high thermal stability, especially when different concentrations of GEO were added. The bioactive CHf showed distinct activity against both Gram-positive and Gram-negative bacteria, such as Staphylococcus aureus, Bacillus subtilis, Streptococcus sp., Escherichia coli, Salmonella sp., and Pseudomonas aeruginosa, thus improving the antimicrobial activity to these films. The results provide a comprehensive insight into the importance of films with incorporated EOs as novel types of active food packaging. Antimicrobial food packaging is one of the most promising kinds of active packaging, and acts to reduce, inhibit, or retard any microorganism growth that could contaminate packaged food items.

Antibacterial Gelidium amansii polysaccharide-based edible films containing cyclic adenosine monophosphate for bioactive packaging

A homogeneous polysaccharide (GAP), with a molecular weight of 51.8 kDa, was isolated from edible red seaweed Gelidium amansii. Composition analysis suggested GAP contained 5.31% sulfate and 17.33% 3,6-anhydro-galactose and was mainly composed of galactose. Furthermore, GAP, as a biopolymer matrix, was used to form the composite films with the small biological molecules cytidine-5′-monophosphate (CMP), adenosine-5′-monophosphate (AMP), and cyclic adenosine monophosphate (cAMP). Scanning electron microscope (SEM), Fourier transform infrared (FTIR) spectrum, and X-ray diffraction (XRD) results showed that CMP, AMP, and cAMP interacted with the film substrates and might made films more complex. Notably, the addition of CMP, AMP, and cAMP promoted the light, water vapor, and oxygen barrier ability, surface wettability, mechanical strength, and antimicrobial activity against Gram-negative and –positive bacteria. Finally, GAP-based films composited with cAMP (cAMPF) exhibited the best characteristics were applied to fish packaging and preservation at 4 °C and extended the fish shelf life. All these data suggested the potential value of cAMPF as a functional edible polysaccharide film applied in food industries.

Biological modification of pentosans in wheat B starch wastewater and preparation of a composite film

BackgroundPetrochemical resources are becoming increasingly scarce, and petroleum-based plastic materials adversely impact the environment. Thus, replacement of petroleum-based materials with new and effective renewable materials is urgently required.ResultsIn this study, a wheat pentosan-degrading bacterium (MXT-1) was isolated from wheat-processing plant wastewater. The MXT-1 strain was identified using molecular biology techniques. The degradation characteristics of the bacteria in wheat pentosan were analyzed. The results show that wheat pentosan was effectively degraded by bacteria. The molecular weight of fermented wheat pentosan decreased from 1730 to 257 kDa. The pentosan before and after the biological modification was mixed with chitosan to prepare a composite film. After fermentation, the water-vapor permeability of the wheat pentosan film decreased from 0.2769 to 0.1286 g mm (m2 h KPa)−1. Results obtained from the Fourier-transformed infrared experiments demonstrate that the wave number of the hydroxyl-stretching vibration peak of the membrane material decreased, and the width of the peak widened. The diffraction peak of the film shifted to the higher 2θ, as seen using X-ray diffraction. The cross-section of the modified composite membrane was observed via scanning electron microscopy, which revealed that the structure was denser; however, no detectable phase separation was observed. These results may indicate improved molecular compatibility between wheat pentosan and chitosan and stronger hydrogen bonding between the molecules. Given the increased number of short-chain wheat pentosan molecules, although the tensile strength of the film decreased, its flexibility increased after fermentation modification.ConclusionThe findings of this study established that the physical properties of polysaccharide films can be improved using strain MXT-1 to ferment and modify wheat pentosan. The compatibility and synergy between pentosan and chitosan molecules was substantially enhanced, and hydrogen bonding was strengthened after biological modification. Therefore, modified pentosan film could be a potential candidate material for edible packaging films.

Freeze–thaw enhanced stability and mechanical strength of polysaccharide‐based sodium alginate/hyaluronic acid films

AbstractAn edible polysaccharide film with high tensile strength and biodegradability was prepared by freeze–thaw treatment with sodium alginate (SA) and hyaluronic acid (HA) and cross‐linking with calcium lactate. The SA/HA ratio, the calcium concentration, the number of freeze–thaw cycles, and the calcification time all have significant effects on the tensile strength of SA/HA films. An increase in tensile strength was obtained due to the reaction of 3% calcium lactate with 60% SA. Compared with the control group, the tensile strength of the SA/HA films developed in this study increased by 214% from 3.188 to 10.02 MPa. The compatibility of films was evaluated by Fourier transform infrared spectroscopy; the absorption peaks of SA and sodium hyaluronate had shifted to a wavelength of 3,403 ~ 3,411 cm−1 after freeze–thaw treatment, and a strong interaction occurred at a wavelength of 1,328 cm−1. In addition, the swelling and solubility of the SA/HA film decreased by half during the freeze–thaw period. Further, scanning electron microscopy showed that the cross sections of the films were uniform and compact after two freeze–thaw treatments. SA/HA films that exhibited increased tensile strength and that had the potential to overcome the poor water vapor barrier problems traditionally experienced with these films were developed in this study.

Soluble soybean polysaccharide films containing in-situ generated silver nanoparticles for antibacterial food packaging applications

In the present study, antibacterial soluble soybean polysaccharide (SSPS)-based nanocomposite films containing in-situ generated silver nanoparticles (AgNPs) were fabricated for food packaging applications. SSPS first reduced silver ions to AgNPs in aqueous solution, and then immobilized these nanoparticles via film casting and drying methods. The formation and homogeneously distribution of AgNPs in glycerol-plasticized SSPS films were confirmed by scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction and transmission electron microscopy. The structure and properties of the SSPS/AgNPs films were characterized via ultraviolet-visible spectroscopy, scanning electron microscopy, thermogravimetry, mechanical testing, water vapor permeability and optical properties measurements. The presence of AgNPs improved the thermal stability and ultra-violet light barrier property of the SSPS films. Antibacterial tests revealed excellent inhibition activity of the SSPS/AgNPs films against different types of bacteria (Escherichia coli and Staphylococcus aureus). The SSPS/AgNPs films could be processed into heat-sealed packaging pouches to extend the shelf life of green grapes.

The Effect of Chitosan Type on Biological and Physicochemical Properties of Films with Propolis Extract.

The aim of the research was to determine the influence of chitosan type and propolis extract concentration on biological and physicochemical properties of chitosan-propolis films in terms of their applicability in food packaging. The films were prepared using three types of chitosan: from crab shells, medium and high molecular weight and propolis concentration in the range of 0.75–5.0%. The prepared polysaccharide films were tested for antimicrobial properties, oxygen transmission rate (OTR) and water vapor transmission rate (WVTR). Moreover, sorption tests and structural analysis were carried out. Microbiological tests indicated the best antimicrobial activity for the film consisting of high molecular weight chitosan and 5.0% propolis extract. Both the type of chitosan and propolis concentration affected transmission parameters—OTR and WVTR. The best barrier properties were recorded for the film composed of high molecular weight chitosan and 5.0% propolis extract. The results of sorption experiments showed a slight influence of chitosan type and a significant effect of propolis extract concentration on equilibrium moisture content of tested films. Moreover, propolis extract concentration affected monolayer water capacity (Mm) estimated using the Guggenheim, Anderson and de Boer (GAB) sorption model. The obtained results indicate that chitosan films with an addition of propolis extract are promising materials for food packaging applications, including food containing probiotic microorganisms.

Layer-by-layer films of polysaccharides modified with poly(N-vinylpyrrolidone) and poly(vinyl alcohol)

N-grafted copolymers of chitosan (460 kDa) with poly(N-vinylpyrrolidone) (2.4 kDa) or poly(vinyl alcohol) (2.0 ​kDa) as side chains were synthesized. Depending on the polymer-to-chitosan mass ratio the degree of amino group substitution with side chains in chitosan backbone was varied in the range of 0.01–0.33. Layer-by-layer films consisted of copolymers and dextran sulfate as polyanion were obtained. Thickness, hydrophilicity, and morphology of the films were investigated using QCM, UV-vis spectrophotometry, AFM, and contact angle measurements. The obtained films show enhanced protein-repellent properties in fetal bovine serum medium. The mass of adsorbed proteins on LbL films based on copolymer with a degree of substitution of 0.2 decreases by 50 ​% compared to unmodified chitosan. Protein-repellent properties of copolymer-based films are common for LbL films of grafted chitosan copolymers and depend on hydrophilic side chain density on the surface.

Polysaccharide-Based Nanocomposites for Food Packaging Applications.

The article presents a review of the literature on the use of polysaccharide bionanocomposites in the context of their potential use as food packaging materials. Composites of this type consist of at least two phases, of which the outer phase is a polysaccharide, and the inner phase (dispersed phase) is an enhancing agent with a particle size of 1–100 nm in at least one dimension. The literature review was carried out using data from the Web of Science database using VosViewer, free software for scientometric analysis. Source analysis concluded that polysaccharides such as chitosan, cellulose, and starch are widely used in food packaging applications, as are reinforcing agents such as silver nanoparticles and cellulose nanostructures (e.g., cellulose nanocrystals and nanocellulose). The addition of reinforcing agents improves the thermal and mechanical stability of the polysaccharide films and nanocomposites. Here we highlighted the nanocomposites containing silver nanoparticles, which exhibited antimicrobial properties. Finally, it can be concluded that polysaccharide-based nanocomposites have sufficient properties to be tested as food packaging materials in a wide spectrum of applications.

Extraction and characterization of polysaccharide films prepared from Furcellaria lumbricalis and Gigartina skottsbergii seaweeds

Extraction and characterization of polysaccharide films prepared from Furcellaria lumbricalis and Gigartina skottsbergii seaweeds

Preparation and characterization of a novel biodegradable film based on sulfated polysaccharide extracted from seaweed Ulva intestinalis.

Seaweeds can be a suitable, inexpensive, abundant, and renewable source for the production of biodegradable films as an alternative to plastics. Sulfated polysaccharides, which are abundant in Ulva intestinalis seaweed, have shown important biological activities such as anticoagulant, antioxidant, antitumor, anti‐inflammatory, and antiviral activities. Mechanical, physicochemical, barrier, and surface properties of sulfated polysaccharide films extracted from Ulva intestinalis using glycerol and polyethylene glycol (PEG) as plasticizers were studied. Ulva intestinalis sulfated polysaccharide films (USP films) were successfully prepared by the incorporation of three concentrations of plasticizers (30, 40, and 50%). The film properties depended on the type and concentration of the plasticizer. Based on the results, by increasing the concentration of the plasticizer, the thickness, moisture content, solubility, and elongation at break of the USP films increased and tensile strength, young's modulus, transparency, and barrier properties of the films decreased. The film plasticized with 30% PEG showed the highest value of tensile strength (36.95 MPa), and the lowest value for permeability to vapor water and oxygen were 1.9 g mm‐1 s‐1kPa‐1 × 10–11 and 7.45 cm‐3.cm/cm2.s.cmHg ×10–8, respectively. Scanning electron microscopy (SEM) observations indicated that the surface of the films was free of bubbles, cracks, or fractures. Fourier transform infrared (FTIR) spectroscopy results revealed some interactions between plasticizers and the polymer.

Physically cross-linked chitosan/dextrin cryogels entrapping Thymus vulgaris essential oil with enhanced mechanical, antioxidant and antifungal properties

Herein, we entrapped Thymus vulgaris essential oil (EO) within the physically cross-linked sponge-like architecture of cryogels by ice template-assisted freeze-drying. Their 3D cryogenically-structured network was built through hydrogen bonding formed by blending two naturally-derived polysaccharides, chitosan and dextrin. The embedment of EOs within the cryogel matrix generates porous films with an increased elasticity that allows their fast shape recovery after full compression. Thus, the swollen EOs-loaded cryogel films exhibited an elastic modulus of 3.00 MPa, which is more than 40 times higher than that of polysaccharide films without EOs (an elastic modulus of only 0.07 MPa). In addition, the encapsulation of bioactive compounds endows the bio-based films with both antioxidant and antifungal properties, showing a radical scavenging activity of 65% and a zone inhibition diameter of 40 mm for Candida parapsilosis fungi. Our results recommend the entrapment of EOs into bio-based cryogel carriers as a straightforward approach to provide ‘green’ polysaccharide-based films having both improved physicochemical properties and remarkable antifungal activity.

Polysaccharide films modified by compounds of natural origin and silver having potential medical applications

In the first stage, seven polysaccharide films were prepared with varying compositions of starch, carboxymethyl starch (CMS), and carboxymethyl cellulose (CMC), together with glycerol and citric acid. From these samples, the most suitable film for possible future applications in medicine in the form of patches was selected based on tensile strength tests, solubility in water, moisture sorption, swelling, and wetting angle. This film (labelled as “V”) contained (in wt%) CMS (2.5), CMC (2.5), citric acid (3), and glycerol (3). In the second stage, the selected film was used for further applications by individually introducing into it appropriate additives with known antimicrobial activity. These additives consisted of terpene compounds of natural origin (α-pinene, menthol, and eugenol) as well as colloidal silver. These four films were then studied to determine the influence of the appropriate additive on moisture absorption, solubility in water, swelling, and antimicrobial activity. The results of the microbiological tests confirmed the antimicrobial activities, and also the anti-infective and regenerative effect of these films. In general, the films containing terpenes showed comparable or better medicinal properties than the film obtained with colloidal silver. A patch prototype (with a medical net) based on the optimal film (“V”) was developed, and its flexibility is apparent in that it can take the shape and size of the area on the human body that it should cover.Graphical

In-Vitro disintegration and dissolution of facile synthesised vegetable capsule films from Abelmoscus esculentus and Gracilaria corticata polysaccharides

The physicochemical properties, in vitro disintegration, and dissolution times of empty vegetable capsule films prepared by the solvent casting method were compared with gelatin films. The morphological properties of the films, such as surface pH (6.2 ± 0.04–6.4 ± 0.05), appearance, OTR (Oxygen Transmission Rate), and thickness (within 70 mm) were also evaluated. The mechanical properties of the capsule films were determined. The Abelmoscus esculentus and Gracilaria corticata polysaccharide films blended at a ratio of 0.5/0.5 showed the highest tensile strength (TS) of 6.8 MPa and the optimum elongation of 23 %, which was higher than that of the gelatin (control) film (p ≤ 0.05). Barrier properties such as the oxygen permeation rate, particularly the A. esculentus film, could be tailored to meet specific requirements by coating the films with metallized PET, metallized CPP, EVOH, and AlO2, or SiO2.

Plasticized Starch/Agar Composite Films: Processing, Morphology, Structure, Mechanical Properties and Surface Hydrophilicity

Natural biopolymers, which are renewable, widely available, biodegradable, and biocompatible, have attracted huge interest in the development of biocomposite materials. Herein, formulation–property relationships for starch/agar composite films were investigated. First, rapid visco analysis was used to confirm the conditions needed for their gelation and to prepare filmogenic solutions. All the original crystalline and/or lamellar structures of starch and agar were destroyed, and films with cohesive and compact structures were formed, as shown by SEM, XRD, and SAXS. All the plasticized films were predominantly amorphous, and the polymorphs of the composite films were closer to that of the agar-only film. FTIR results suggest that the incorporation of agar restricted starch chain interaction and rearrangement. The addition of agar to starch increased both tensile strength and elongation at break, but the improvements were insignificant after the agar content was over 50 wt.%. Contact angle results indicate that compared with the other samples, the 4:6 (wt./wt.) starch/agar film was less hydrophilic. Thus, this work shows that agar dominates the structure and properties of starch/agar composites, and the best properties can be obtained with a certain starch/agar ratio. Such composite polysaccharide films with tailored mechanical properties and surface hydrophilicity could be useful in biodegradable packaging and biomedical applications (wound dressing and tissue scaffolding).

Essential Oil-Containing Polysaccharide-Based Edible Films and Coatings for Food Security Applications.

The wastage of food products is a major challenge for the food industry. In this regard, the use of edible films and coatings have gained much attention due to their ability to prevent the spoilage of the food products during handling, transport, and storage. This has effectively helped in extending the shelf-life of the food products. Among the various polymers, polysaccharides have been explored to develop edible films and coatings in the last decade. Such polymeric systems have shown great promise in microbial food safety applications. The inclusion of essential oils (EOs) within the polysaccharide matrices has further improved the functional properties of the edible films and coatings. The current review will discuss the different types of polysaccharides, EOs, methods of preparing edible films and coatings, and the characterization methods for the EO-loaded polysaccharide films. The mechanism of the antimicrobial activity of the EOs has also been discussed in brief.