Production of starch based biopolymer by green photochemical reaction at different UV region as a food packaging material: Physicochemical characterization.

In current study, the functional properties of modified starch solutions by photochemical reactions as a biodegradable food packaging material were investigated. Starch film-forming solutions were exposed to ultraviolet A (UV-A) and C (UV-C) over different time periods (1, 6, 12, and 24 h). A green method was used to prepare the modified starch films. Hydrophobicity, moisture sensitivity, and water vapor permeability of the starch films, decreased after exposure to UV irradiation up to 12 h. Tensile strength and Young's modulus of the specimens decreased by increasing UV exposure time. Elongation at break, and tensile energy to break of the film specimens were increased, simultaneously. Scanning electron microscopy images demonstrated that most of the films' physical properties were affected by their microstructures. UV-Vis spectrum of the specimens confirmed that UV-protective properties of the irradiated specimens in UV-A, UV-B, and UV-C region have changed in comparison with the control sample. According to the results, UV-irradiation could be considered as a green, easy, and accessible process for modification of starch-based films.

Development of photo-modified starch/kefiran/TiO2 bio-nanocomposite as an environmentally-friendly food packaging material.

This paper reports on an experiment in which starch/kefiran/TiO2 (SKT)-based bio-nanocomposite films were developed and modified by photo-chemical reaction. In so doing, film-forming solutions were exposed to ultraviolet A (UV-A) for different times (1, 6, and 12 h). The obtained results indicated that increasing UV-A exposure time brought about an increase (≈14.9%) in the tensile strength of bio-nanocomposites. However, elongation at break and Young's modulus of irradiated film specimen decreased (≈32%, ≈12%, respectively) by increasing UV-A exposure time, and the moisture-sensitive parameters of specimen decreased using UV-A irradiation. According to the results, the functional properties of irradiated bio-nanocomposite are depended on the ratio of cross-linkages between polymer chains and the potentially produced mono and disaccharide by UV-A.

Photo-producible and photo-degradable starch/TiO2 bionanocomposite as a food packaging material: Development and characterization.

In current study, starch/TiO2 bionanocomposites were produced by photochemical reactions as a biodegradable food packaging material. Physical, mechanical, thermal and water-vapor permeability properties were investigated. Then, the photo-degradation properties of nanocomposite films were studied. This is the first report of the photo-producible and photo-degradable bionanocomposite as a food packaging material. Film-forming solutions were exposed to ultraviolet A (UV-A) for different times. Our results showed that UV-A irradiation increased the hydrophobicity of starch films. With increasing UV-A exposure time, tensile strength and Young's modulus of the specimens were decreased. On the other hand, elongation at break of the films was increased with increasing UV-A irradiation. The glass transition temperature and melting point of the films were increased by increasing UV-A exposure time. Nevertheless, the results showed that photo-degradation properties of photo-produced starch/TiO2 nanocomposite were significantly higher than virgin starch and virgin starch/TiO2 films. According to obtain results and bibliography a schema was developed to describe the mechanism of photo-production and photo-degradation of starch/TiO2 by UV-A ray. It can be concluded, the modification of starch based biopolymer by UV-A and nano-TiO2, is an easy and accessible process to improve the packaging properties and photo-degradability of biopolymer based films.

Preparation of ecofriendly UV-protective food packaging material by starch/TiO2 bio-nanocomposite: Characterization.

In this study, ecofriendly starch/TiO2 bio-nanocomposites were produced using with different nano-TiO2 (TiO2) content (1, 3, and 5 (wt%)). Physical, mechanical, thermal, water-vapor permeability (WVP) properties and UV transmittance were investigated. Our results showed that the increasing TiO2 content increased the hydrophobicity of starch/TiO2 films. WVP of the bio-nanocomposites was reduced, simultaneously. With increasing TiO2 content, tensile strength and Young's modulus of the film specimens were reduced while elongation at break and tensile energy to break were increased. The thermal properties of specimens showed that glass transition temperature of the films increased but melting point of the specimen films was decreased by increasing TiO2 content. Scanning electron microscopy observations demonstrated, the most of films' physical properties were in relation to their microstructures. The starch/TiO2 nanocomposites effectively protect goods against UV light, and could potentially be applied as UV-shielding packaging materials.