Application of cold plasma to develop carboxymethyl cellulose-coated polypropylene films containing essential oil.

This study was aimed to develop and characterize carboxymethyl cellulose-coated polypropylene (PP/CMC) films with Zataria multiflora essential oil (ZEO) as a new antimicrobial food packaging. For better attachment of CMC on polypropylene (PP) film surface, atmospheric plasma pretreatment was used. Results showed the formation of polar groups such as CO and OH in the PP surface following the plasma treatment. Plasma-treated PP had rougher surfaces and their contact angle reduced from 88.92° to 52.15° indicating increased surface hydrophilicity. Plasma-treated PP/CMC films showed lower water vapor permeability (WVP) and higher tensile strength compared to untreated bilayer films. Results revealed that antimicrobial PP/CMC films with higher content of ZEO had lower WVP, but was more sensitive to breakage. Antimicrobial characteristics in the direct contact and vapor phase represented great inhibition for all the tested bacteria. Our findings suggest that plasma-treated PP/CMC films have the potential for application in food antimicrobial packaging.

Development and characterisation of chitosan or alginate-coated low density polyethylene films containing Satureja hortensis extract.

This study aimed to develop novel bilayer films based on alginate, chitosan and low-density polyethylene (LDPE) containing different concentrations of summer savory extract (SSE). The cold atmospheric plasma system was used to increase the surface energy of LDPE. Initially, water contact angle, surface roughness and the functional group of LDPE before and after plasma treatment were investigated. Then physical, mechanical, optical, antioxidant and microstructure properties of plasma-treated and untreated bilayer films and antioxidant films incorporated with SSE were characterized. Results showed that plasma treatment increased oxygen-containing the polar group, surface roughness and decreased water contact angle of LDPE surface (from 90.47° to 48.73°) and in result enhanced adhesion between polysaccharide coating and LDPE. Tensile strength of both alginate and chitosan coated-LDPE increased from 10.096 to 14.372 and 11.513 to 13.459MPa, respectively after plasma pretreatment. However chitosan-based films had lower water solubility. Although, incorporation of SSE into chitosan and alginate coated-LDPE despite slight adverse effects on the physical and mechanical properties of films, it provided antioxidant activity. Chitosan coated-LDPE containing SSE had potential to use as antioxidant food packaging.

Nanocomposites in food packaging applications and their risk assessment for health.

Nanotechnology has shown many advantages in different fields. As the uses of nanotechnology have progressed, it has been found to be a promising technology for the food packaging industry in the global market. It has proven capabilities that are valuable in packaging foods, including improved barriers; mechanical, thermal, and biodegradable properties; and applications in active and intelligent food packaging. Examples of the latter are anti-microbial agents and nanosensors, respectively. However, the use of nanocomposites in food packaging might be challenging due to the reduced particle size of nanomaterials and the fact that the chemical and physical characteristics of such tiny materials may be quite different from those of their macro-scale counterparts. In order to discuss the potential risks of nanoparticles for consumers, in addition to the quantification of data, a thorough investigation of their characteristics is required. Migration studies must be conducted to determine the amounts of nanomaterials released into the food matrices. In this article, different applications of nanocomposites in food packaging, migration issues, analyzing techniques, and the main concerns about their usage are discussed briefly.