Characterisation of ferulic acid incorporated starch–chitosan blend films

Preparation of extruded polyethylene/chitosan blends compatibilized with polyethylene-graft-maleic anhydride

Novel films of polyethylene and chitosan were obtained using extrusion. These polymers have interesting properties, and processing them with methods that are of high use in the industry, such as the extrusion method, can have a significant effect on the potential applications of these materials. The individual materials were thermally characterized; after this, extruded films of low density polyethylene and chitosan mixtures were prepared with the addition of polyethylene-graft-maleic anhydride as a compatibilizer for the blends, and glycerol, as a plasticizer for chitosan. The use of compatibilizer and plasticizer agents improved the processability and compatibility of the mixtures, as well as their mechanical properties, as revealed by mechanical property measurements and scanning electron microscopy. It was possible to prepare blends with a maximum chitosan content of 20 wt%. The material stiffness increased with the increase of chitosan in the sample. FTIR studies revealed the existence of an interaction between the compatibilizer and chitosan.

Physio-mechanical properties of an active chitosan film incorporated with montmorillonite and natural antioxidants extracted from pomegranate rind

An active film was prepared from chitosan incorporated with montmorillonite (MMT) and pomegranate rind powder extract (PRP). The effect of MMT (1 %, 3 %, and 5 % w/w chitosan) and PRP (1 %, 1.5 %, and 2 % w/v chitosan) on the physical, mechanical and antioxidant properties of the chitosan-based films was studied. Fourier transform infrared (FTIR) spectra revealed that good interactions occurred between functional groups of chitosan with MMT or with PRP. The results showed that the water vapor barrier property of the films was significantly improved by incorporation of MMT and PRP (p < 0.05). When compared to pure chitosan film, the WVP of M3P2 film (Chitosan/3 % MMT/2 % PRP) decreased by 25.2 %. Tensile strength of the films was affected by the addition of MMT and PRP. However, percent elongation at break was not significantly changed by addition of PRP. The film incorporated with 3 % MMT and 2 % PRP that contained the highest amount of total phenolic (15.2 mg GAE/g DW), was found to be the most active radical scavenger. These results suggest that chitosan films containing MMT and PRP can be used for development of active food packaging materials.

Microstructure and characteristics of high-amylose corn starch−chitosan film as affected by composition

Edible films composed of high-amylose corn starch and chitosan were developed by casting method. The effects of the ratio of high-amylose corn starch to chitosan, concentration of glycerol and methyl cellulose on the oxygen and carbon dioxide permeation, water vapor transmission, tensile strength and percent elongation at break values of edible composite films were investigated. Film microstructure was characterized by scanning electron microscopy. The results showed that the increase of the ratio of chitosan and content of glycerol in the film forming suspensions both made the structure of films flexible, causing the decrease of tensile strength and increase of percent elongation of composite films, while showing poor water vapor barrier properties as the water vapor transmission values increased. The addition of methyl cellulose as to reinforce the structure of matrix improved the water vapor barrier properties of the edible films with the decrease of water vapor transmission from 1946 to 1668 g/(m2·24 h), as well as the mechanical properties were improved as expected, which could be attributed to the differentia of the interaction between methyl cellulose and other components in the film preparation as the concentration ranged from 2% (w/w) to 8% (w/w). Films with different compositions, resulting different microstructures, showed variance in barrier and mechanical properties.

Preparation of Novel Chitosan-Starch Blends as Thickening Agent and Their Application in Textile Printing

Chitosan, a naturally available biopolymer which is now increasingly used as a functional finish on textile substrates to impart antimicrobial characteristics and increase dye uptake of fabrics, was blended with different ratios of gelatinized starch. The chitosan was extracted and characterized by IR,1H-NMR, and X-ray powder diffraction. These blends were tested as thickeners in textile screen printing usingCurcuma tinctoriaas natural dye. The rheological properties and the viscosity of the printing paste were measured. The effect of chitosan on the printing properties of different fabrics (natural, blends, and synthetic fabrics) was studied by measuring the color strength value (K/S) and related color parameters of the printed fabrics. The antimicrobial properties of printed fabrics were assessed. The results proved that the printed fabrics using these new thickeners showed increase in the color strength value (K/S) giving darker color which means that chitosan increased the dye uptake on fabrics. Fastness properties of the printed fabrics to washing, rubbing, perspiration, and light have also been improved. The treated fabrics were found to be antimicrobial.

Chitosan-caffeic acid-genipin films presenting enhanced antioxidant activity and stability in acidic media

The use of chitosan films has been limited due to their high degradability in aqueous acidic media. In order to produce chitosan films with high antioxidant activity and insoluble in acid solutions caffeic acid was grafted to chitosan by a radical mechanism using ammonium cerium (IV) nitrate (60 mM). Genipin was used as cross-linker. This methodology originated films with 80% higher antioxidant activity than the pristine film. Also, these films only lost 11% of their mass upon seven days immersion into an aqueous solution at pH 3.5 under stirring. The films surface wettability (contact angle 105°), mechanical properties (68 MPa of tensile strength and 4% of elongation at break), and thermal stability for temperatures lower than 300 °C were not significantly influenced by the covalent linkage of caffeic acid and genipin to chitosan. Due to their characteristics, mainly higher antioxidant activity and lower solubility, these are promising materials to be used as active films.

SYNTHESIS OF ELECTROSPRAYED CHITOSAN NANOPARTICLES FOR DRUG SUSTAINED RELEASE

Chitosan (CS) nanoparticles for drug delivery were fabricated by an electrospraying method. The effects of CS molecular weight on electrospraying were investigated. The size and morphology of CS particles were strongly influenced by CS molecular weight. Besides, CS concentration, electrical field, acetic acid concentration, and solution feeding rate in the electrospraying process were also studied. To evaluate the potential of electrosprayed CS nanoparticles in drug delivery, indomethacin (ID) was used as a model drug, where the encapsulation efficiency, the loading capacity, and the releasing profiles were identified. The CS-ID spherical nanoparticles were fabricated by the electrospraying technique, with the average diameter of 340 nm. Zeta potential of the ID-CS particles indicated that the particles were stable in the suspension. The encapsulation efficiency (EE) and loading capacity (LC) of ID were higher for 150-kDa CS than for 310-kDa CS. The EE of ID in electrosprayed CS particles was higher than that in particles prepared by other methods. The release profiles revealed that there were two stages for releasing and the long-term delivery could be obtained in the second stage. In summary, this research optimized the electrospraying process for the fabrication of CS nanoparticles and demonstrated the potential of electrosprayed CS nanoparticles as a drug carrier.

Preparation, characterization and evaluation of biocomposite films containing chitosan and sago starch impregnated with silver nanoparticles

The positive attributes of excellent biocompatibility and biodegradability of biopolymers with versatile biological activities have provided ample opportunities for further development of functional biomaterials of high potential in various fields. The biopolymers used in this study, i.e. chitosan and sago starch are abundantly available in nature and can be used in various biomedical applications. In the present study, the composite films of chitosan (Ch) and sago starch (SG) impregnated with silver nanoparticles (AgNP) with and without antibiotic gentamicin (G) were prepared by solvent casting method. The films prepared were characterized for their physic-chemical properties using conventional methods. The results obtained showed that with the increase of chitosan content in the composite results in decrease in its water absorption capacity. The FTIR and SEM studies have shown the composite nature of the films prepared. Ch-SG-AgNP and Ch-SG-AgNP-G composites were used as wound dressing materials in experimental wounds of rats. The healing pattern of the wounds was evaluated by planimetric studies, macroscopic observations, biochemical studies and histopathological observations. The results have shown faster healing pattern in the wounds treated with Ch-SG-AgNP and Ch-SG-AgNP-G composites compared to untreated control. This study suggests that Ch-SG-AgNP film may be a potential candidate as a dressing material for wound healing applications.

Progress in antimicrobial activities of chitin, chitosan and its oligosaccharides: a systematic study needs for food applications

In recent years, active biomolecules such as chitosan and its derivatives are undergoing a significant and very fast development in food application area. Due to recent outbreaks of contaminations associated with food products, there have been growing concerns regarding the negative environmental impact of packaging materials of antimicrobial biofilms, which have been studied. Chitosan has a great potential for a wide range of applications due to its biodegradability, biocompatibility, antimicrobial activity, nontoxicity and versatile chemical and physical properties. It can be formed into fibers, films, gels, sponges, beads or nanoparticles. Chitosan films have been used as a packaging material for the quality preservation of a variety of foods. Chitosan has high antimicrobial activities against a wide variety of pathogenic and spoilage microorganisms, including fungi, and Gram-positive and Gram-negative bacteria. A tremendous effort has been made over the past decade to develop and test films with antimicrobial properties to improve food safety and shelf-life. This review highlights the preparation, mechanism, antimicrobial activity, optimization of biocide properties of chitosan films and applications including biocatalysts for the improvement of quality and shelf-life of foods.

Wettability, surface microstructure and mechanical properties of films based on phosphorus oxychloride-treated zein

BACKGROUND

Zein, the predominant protein in corn, has been extensively studied as an alternative packaging material in edible and biodegradable films. However, films made from 100% zein are brittle under normal conditions. The aim of this investigation was to improve the film-forming properties of zein by chemical phosphorylation. The surface hydrophobicity, surface microstructure and mechanical properties of films based on untreated and phosphorus oxychloride (POCl(3))-treated zein were evaluated and compared. The effect of POCl(3) treatment on the rheological properties of zein solutions was also studied.

RESULTS

POCl(3) treatment, especially at pH 7 and 9, led to an increase in the apparent viscosity of zein solutions. Atomic force microscopy (AFM) analysis showed that the film based on POCl(3) -treated zein at pH 7 had a stone-like surface microstructure with a higher roughness (R(q)) than the untreated zein film. The AFM data may partially account for the phenomenon that this film exhibited high surface hydrophobicity (H(0) ). POCl(3) treatment diminished the tensile strength (TS) of zein films from 4.83-6.67 to 1.3-2.29 MPa. However, the elongation at break (EAB) of the films at pH 7 and 9 increased from 3.0-4.5% (control film) to 150.1-122.7% (POCl(3) -treated film), indicating the potential application of zein films in wrapping foods or in non-food industries such as sugar, fruit or troche that need good extension packing materials.

CONCLUSION

The data presented suggest that the properties of zein films could be modulated by chemical phosphorylation treatment with POCl(3) at an appropriate pH value.

Enhancing water repellence and mechanical properties of gelatin films by tannin addition

In order to reduce pollution caused by traditional non-biodegradable plastic films, renewable raw materials from plants and wastes of meat industries have been employed in this work. A hydrolysable chestnut-tree tannin was used for gelatin modification. Films of gelatin and gelatin-tannin were obtained by casting at room conditions. Transition temperatures of both gelatin and gelatin-tannin systems were determined by differential scanning calorimetry (DSC). Glass transition temperatures of modified gelatin occurred at higher temperatures than for neat gelatin. Enthalpy and temperature of helix-coil transition decreased when tannin content increased due to variations in the helical structure of gelatin as a consequence of tannin presence in agreement with X-ray analysis. Mechanical and thermal behaviour varied as a function of the content of tannin, showing optimum values for films modified with 10 wt% tannin. The transparency of films was maintained after modification with tannin. Solubility and swelling tests of the films revealed that the presence of tannin reduced the water affinity of gelatin.