Physicochemical, Water Vapor Barrier and Mechanical Properties of Corn Starch and Chitosan Composite Films

Chitosan-based mucoadhesive films loaded with curcumin for topical treatment of oral cancer

This study aimed to develop mucoadhesive chitosan-based films capable of enhancing the curcumin penetration into the oral mucosa to treat oral cancers. We developed three films containing medium molecular weight chitosan (190-310 KDa) and other excipients (polyvinyl alcohol, Poloxamer®407, and propylene glycol) that have proven to be compatible with each other and with curcumin in thermal analyses. The films were smooth, flexible, and precipitates free, with uniform weight and thickness, pH compatible with the oral mucosa, resistance to traction, and entrapped curcumin in a high proportion. They also exhibited necessary swelling and mucoadhesion for tissue adherence. Ex vivo penetration studies proved that the films significantly increased the penetration of curcumin into the oral mucosa compared to control, even when the mucosa was subjected to a condition of simulated salivation. Curcumin exhibited cytotoxic activity in vitro in the two head and neck cancer cell lines (FaDu, SCC-9) at doses close to those found in penetration studies with the films. When combined with radiotherapy, curcumin demonstrated superiority over single doses of radiotherapy at 4, 8, and 12 Gy. Therefore, the developed films may represent a promising alternative for the topical treatment of oral tumors.

Corn: Its Structure, Polymer, Fiber, Composite, Properties, and Applications

Biocomposite materials have a significant function in saving the environment by replacing artificial plastic materials with natural substances. They have been enrolled in many applications, such as housing, automotive engine components, aerospace and military products, electronic and circuit board components, and oil and gas equipment. Therefore, continuous studies have been employed to improve their mechanical, thermal, physical properties. In this research, we conduct a comprehensive review about corn fiber and corn starch-based biocomposite. The results gained from previous studies were compared and discussed. Firstly, the chemical, thermal, and mechanical properties of cornstarch-based composite were discussed. Then, the effects of various types of plasticizers on the flexibility of the cornstarch-based composite were addressed. The effects of chemical treatments on the properties of biocomposite using different cross-linking agents were discussed. The corn fiber surface treatment to enhance interfacial adhesion between natural fiber and polymeric matrix also were addressed. Finally, morphological characterization, crystallinity degree, and measurement of vapor permeability, degradation, and uptake of water were discussed. The mechanical, thermal, and water resistance properties of corn starch and fibers-based biopolymers show a significant improvement through plasticizing, chemical treatment, grafting, and cross-linker agent procedures, which expands their potential applications.

Extraction and Physico-Chemical Characterization of Chitosan from Mantis Shrimp (Oratosquilla nepa) Shell and the Development of Bio-Composite Film with Agarose

Mantis shrimp (Oratosquilla nepa) exoskeleton, a leftover generated after processing, was used as a starting material for chitosan (CS) production. CS was extracted with different deacetylation times (2, 3 and 4 h), termed CS−2, CS−3 and CS−4, respectively, and their characteristics and antimicrobial and film properties with agarose (AG) were investigated. Prolonged deacetylation time increased the degree of deacetylation (DDA: 73.56 ± 0.09−75.56 ± 0.09%), while extraction yield (15.79 ± 0.19−14.13 ± 0.09%), intrinsic viscosity (η: 3.58 ± 0.09−2.97 ± 0.16 dL/g) and average molecular weight (Mν: 1.4 ± 0.05−1.12 ± 0.08 (×106 Da)) decreased (p < 0.05). FTIR spectra of extracted CS were similar to that of commercial CS. Among all the CS samples prepared, CS−3 had the best yield, DDA, Mν and antimicrobial activity. Therefore, it was chosen for the development of composite films with AG at different ratios (CS−3/AG; 100/0, 75/25, 50/50, 25/75 and 0/100). As the proportion of AG increased, the tensile strength (29.96 ± 1.80−89.70 ± 5.08 MPa) of the composite films increased, while thickness (0.056 ± 0.012−0.024 ± 0.001 mm), elongation at break (36.52 ± 1.12−25.32 ± 1.23%) and water vapor permeability (3.56 ± 0.10−1.55 ± 0.02 (×10−7 g m m−2 s−1 Pa−1)) decreased (p < 0.05). Moreover, lightness of the films increased and yellowness decreased. CS−3/AG (50/50) composite film exhibited high mechanical and barrier properties and excellent compatibility according to FTIR and SEM analyses. According to these finding, mantis shrimp exoskeleton could be used to produce CS. The developed bio-composite film based on an appropriate ratio (50/50) of CS−3 and AG has potential for being used as food packaging material.

Chitosan/gelatin films with jatobá resin: Control of properties by vegetal resin inclusion and degree of acetylation modification

Blending chitosan and gelatin, two biodegradable and non-toxic polymers, is a recurrent choice in food coating or biomaterials development. The incorporation of vegetal extracts into chitosan/gelatin films can improve or introduce some properties to these materials. Jatobá resin is a product of Hymenaea genus trees with antimicrobial and anti-inflammatory activities, interesting properties for films applied in several areas. The chitosan degree of acetylation (DA) influences the inter and intramolecular interactions of this polymer and, therefore, also implicates in changes of its properties. This research aims to study the influence of jatobá resin inclusion and chitosan DA modification on chitosan/gelatin films properties. Both jatobá resin and chitosan DA affected physicochemical, antimicrobial and barrier properties of the films, allowing the control of these properties by changes in these parameters. Jatobá resin incorporation and the decrease in chitosan DA significantly improved antimicrobial activity and water vapor permeability of films with the reduction of water solubility and swelling.

Preparation, and physicochemical and biological evaluation of chitosan-Arthrospira platensis polysaccharide active films for food packaging

Active films from chitosan incorporated with Arthrospira platensis polysaccharide (APP) of various ratios (0.0%, 0.5%, and 1.0%, w/v) were developed by solution casting. The effect of APP on the structural, physicochemical, mechanical, antimicrobial, and antioxidant properties of the chitosan-APP films (CA-film) was investigated. Fourier transform infrared spectra (FTIR) confirmed successful incorporation of chitosan and APP. The compact structure of the films was observed clearly in scanning electron microscopy (SEM) and atomic force microscopy (AFM) images. X-ray diffraction (XRD) patterns suggest the semi-crystalline structure was increased upon addition of APP. The composite films showed an improved water resistance and vapor barrier properties, and reduced by at least 27.4% and 32.1% in swelling degree (S_d ) and water vapor permeability (WVP) compared with chitosan film (C-film), respectively. However, the transparency decreased slightly, which may be due to the shrinkage of the spacing of the polymer interchain. The composite films also displayed enhanced the mechanical properties. The antimicrobial activity of the CA-film showed an increase of at least of 0.41-fold in inhibition zone diameter for E. coli. At a concentration of 1.2 mg/mL, the antioxidant activity of CA-film was enhanced by more than threefold compared with C-film. Therefore, CA-films have good potential as sources of active packaging material for the food industry.

Biodegradable Starch/Chitosan Foam via Microwave Assisted Preparation: Morphology and Performance Properties

The effects of chitosan (CTS) as the reinforcing phase on the properties of potato starch (PS)-based foams were studied in this work. The formic acid solutions of CTS and PS were uniformly mixed in a particular ratio by blending and then placed in a mold made of polytetrafluoroethylene for microwave treatment to form starch foam. The results showed that the molecular weight and concentration of CTS could effectively improve the density and compressive properties of starch-based foams. Furthermore, orthogonal experiments were designed, and the results showed that when the molecular weight of CTS in foams is 4.4 × 10⁵, the mass fraction is 4 wt%, and the mass ratio of CTS–PS is 3/4.2; the compressive strength of foams is the highest at approximately 1.077 mPa. Furthermore, Fourier transform infrared spectroscopy analysis demonstrated the interaction between starch and CTS, which confirmed that the compatibility between CTS and PS is excellent.

Traditional Sensory Evaluation and Bionic Electronic Nose as Innovative Tools for the Packaging Performance Evaluation of Chitosan Film

Inspired by the natural epidermis of animals and plants with antioxidant and antibacterial properties, the aim of this research was to characterize and analyze the effects of the chitosan concentrations on properties of glycerol plasticized chitosan (GPC) film and to investigate the suitability of sensory evaluation and bionic electronic nose (b-electronic nose) detection to assess the freshness of ground beef packaged in the GPC film. The increase in chitosan concentration resulted in an increase in solubility value, total color differences and color intensity of chitosan films. The water vapor permeability (WVP) of the GPC films decreased with the increasing of the chitosan concentration and then increased at higher chitosan concentrations. Longer storage time led to poorer freshness of the ground beef and the GPC film could keep beef samples fresher and delay the deterioration of the beef. Both the traditional sensory evaluation and b-electronic nose technology were fit for evaluating the quality and shelf-life of ground beef, which could advantageously be applied in the future for analyzing other bionic food packaging materials.

Improved structure-stability and packaging characters of crosslinked collagen fiber-based film with casein, keratin and SPI

BACKGROUND

To improve the structure-stability and packing characters of collagen fiber, we manufactured crosslinked collagen fiber (CColF)-based edible films using transglutaminase (TGase). Then we made a comparison on structure-stability and packing characteristics among the CColF-based films loaded with casein (CN), keratin (KRT) and soy protein isolate (SPI), respectively.

RESULTS

Observed from scanning electron microscopy (SEM), the CColF loaded with CN, KRT and SPI showed some unique morphology of the additional proteins. The CColF-protein films performed better packing characteristics including barrier properties, mechanical properties and thermal-stability properties, compared with CColF films. Importantly, with 500 g kg^-1 CN (of CColF) addition, CColF-based films possessed a greater thermal stability than the other films judged from differential scanning calorimetry (DSC). Meanwhile, the CColF loaded with 100 g kg^-1 CN provided a higher value of tensile strength (TS) and the CColF loaded with 100 g kg^-1 KRT showed a higher value in elongation-at-break (EAB) than the other films.

CONCLUSION

In conclusion, the collagen fiber-based edible films with better structure-stability and packing characteristics for food packaging was obtained which could be an advantage to promote the development of the application of collagen in packing products. © 2019 Society of Chemical Industry.

Optimisation of compatibility for improving elongation at break of chitosan/starch films

When chitosan/starch films were used as agricultural mulch films, the problem of rupture often occurred. In order to improve the elongation at break, chitosan/starch blend films were prepared by casting with different formulations (different ratios of chitosan to starch, different plasticizing components and different plasticizer ratios) in this research. The elongation at break of the film reached up to 104.1% when chitosan was plasticized with 10% glycerol and 0.94% ethylene glycol alone and then mixed according to a 1 : 0.6 chitosan–starch ratio. The fact that plasticizing starch, plasticizing chitosan or co-plasticizing starch and chitosan made a big difference to the mechanical properties of the films was discovered for the first time. The films with different plasticizing components were characterized by their mechanical properties, crystal structures and surface morphologies. Mechanical properties of the films were related to their crystallinity. The higher the crystallinity, the higher the elongation at break. Plasticizing starch alone facilitated the formation of hydrogen bonds and massive structures. Plasticizing chitosan alone was beneficial to the formation of network structures of the films and exhibited anti-plasticization at low plasticizer concentration.

Three methods were used to improve the elongation at break of chitosan/starch films to obtain the optimal compatibility.

Effect of starch osmo-coating on carotenoids, colour and microstructure of dehydrated pumpkin slices

Carotenoids in pumpkins are extremely unstable during industrial drying, to avoid the carotenoid degradation, starch omso-coating was subjected to the pretreatment process for dehydrated pumpkin slices. The results showed that starch omso-coating reduced the dehydration rate of pumpkin slices. When coated with corn starch, the retention rates of lutein, α-carotene and β-carotene in dehydrated pumpkin slices significantly increased by 11.3, 9.0 and 7.7%, respectively, and the provitamin A activity increased by 9.5%. 1% (w/v) modified corn omso-coating gave highest retention rate of total carotenoids (95.5%), while provitamin A activity reached 4148 µg RAE/100 g. In addition, the colour parameters △E and a* values reduced, but L*, b* and H values increased with coated samples. Pearson correlation analysis showed that lutein, α-carotene and β-carotene were significantly positive correlated with L*, and exhibited negative correlations with △E. The SEM indicated starch granules was attached to tissue gap and caused the film formation of oxygen barrier. It could be concluded that modified corn coating effectively improved the quality of final product.

Development of Burdock Root Inulin/Chitosan Blend Films Containing Oregano and Thyme Essential Oils

In this study, inulin (INU) extracted from burdock root was utilized as a new film base material and combined with chitosan (CHI) to prepare composite films. Oregano and thyme essential oils (OT) were incorporated into the INU-CHI film to confer the films with bioactivities. The physical and optical properties as well as antioxidant and antimicrobial activities of the films were evaluated. INU film alone showed poor physical properties. In contrast, the compatibility of INU and CHI demonstrated by the changes in attenuated total reflectance-Fourier transformation infrared spectrum of the INU-CHI film increased tensile strength and elongation at break of the INU film by 8.2- and 3.9-fold, respectively. In addition, water vapor permeability, water solubility, and moisture content of the films decreased proportionally with increasing OT concentration in the INU-CHI film. Incorporation of OT also increased the opacity of a and b values and decreased the L value of the INU-CHI films. All INU-CHI films containing OT exhibited antioxidant and antimicrobial properties. Particularly, the INU-CHI film with 2.0% OT exhibited the highest 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid), 2,2-diphenyl-1-picrylhydrazyl radical scavenging, and antimicrobial activities against four pathogens. Thus, the INU-CHI film containing OT developed in this study might be utilized as an active packaging material in the food industry.

Preparation and characterization of crosslinked chitosan/gelatin scaffolds by ice segregation induced self-assembly

Chitosan and gelatin are biodegradable and biocompatible polymers which may be used in the preparation of 3D scaffolds with applications in biomedicine. Chitosan/gelatin scaffolds crosslinked with glutaraldehyde were prepared by ice segregation induced self-assembly (ISISA); a unidirectional freezing at -196°C followed freeze-drying to produce macroporous materials with a well-patterned structure. This process may be included within the green chemistry by the preparation of the porous structures without using organic solvents, moreover is a versatile, non-difficult and cheap process. The scaffolds prepared by ISISA were characterized by scanning electron microscopy, attenuated total reflectance Fourier transform infrared spectroscopy, thermal gravimetric analysis, differential scanning calorimetry, and their stability was evaluated by degree swelling and degradation tests. The scaffolds present properties as high porosity, high degree swelling and good stability which make them suitable of applications as biomaterials.

Laminados biodegradáveis de blendas de amido de mandioca e poli(vinil álcool): efeito da formulação sobre a cor e opacidade

<title>Resumo</title><p>Foram produzidos 12 laminados com diferentes proporções de amido de mandioca, poli(vinil álcool) (PVA) e glicerol por extrusão usando um planejamento de mistura. A opacidade dos materiais variou entre 31 e 56%, e a concentração de PVA e a interação entre as concentrações de amido e PVA foram os principais responsáveis pelo aumento da opacidade. A diferença de cor (ΔE*) variou entre 20-30, sendo a concentração de amido o principal responsável pelo aumento da diferença de cor, por promover uma coloração mais amarelada nos laminados.</p>

Properties of edible films based on pullulan–chitosan blended film-forming solutions at different pH

Influences of solution pH on the properties of pullulan–chitosan blended (Pul–Chi) films and the rheological properties of film-forming solutions were investigated.

Physicochemical, mechanical and thermal properties of chitosan films with and without sorbitol

The effect of sorbitol on the physicochemical, mechanical and thermal properties of chitosan films with different degrees of deacetylation (DD; i.e., DD85% and DD95%) was investigated. The thickness, moisture content (MC), water solubility (WS) and water-vapor permeability (WVP) of the films were evaluated. Sorbitol addition reduced MC, increased WS and significantly (p<0.01) reduced WVP of both film types. DD95% films had lower MC and WVP, and higher WS than DD85% films. Static (thermomechanical analysis) and dynamic (dynamic mechanical analysis) tests indicated that sorbitol increased the strain and decreased stress for both DD films, but DD95% could sustain higher strain and DD85% could sustain higher stress. Thermogravimetrics analysis and differential scanning calorimetry showed that sorbitol elicited a lower degradation temperature for both films, and that DD95% films exhibited higher thermal stability than DD85% films.