Effect of Compatibilisers on Mechanical, Barrier and Antimicrobial Properties of iPP/ZnO Nano/Microcomposites for Food Packaging Application

It is investigated the effects of the addition of three PPgMA, with different molecular weight and maleic anhydride content, on the structure, morphology, mechanical, thermal and antimicrobial properties and oxygen permeability of iPP/ZnO 98/2 wt% composite. The composition of iPP/PPgMA/ZnO composites is fixed at 88/10/2 wt%, that is, about 10 wt% of iPP is substituted with PPgMA. The composites are prepared via melt mixing by using a twin-screw extruder. The ZnO is obtained in a preindustrial scale spray pyrolysis platform. The Fourier Transform Infrared spectroscopy indicates that the ZnO particles, in all the ternary composites, react with maleic anhydride groups of PPgMA. From the analyses of the mechanical properties, permeability to oxygen and antibacterial activity agaist E.Coli, it is concluded that the best compatibiliser among the three is PPgMA with 1.4% of MA and Mw 65,000, but the antibacterial activity is much lower than that of the binary iPP/ZnO 98/2 wt%. Moreover, it is found that the antibacterial activity is more efficient for the film that presents clusters of the ZnO particles on the surface than the film with ZnO particles smaller and better distributed on the film surface, and embedded in it

Assessment on the Effects of ZnO and Coated ZnO Particles on iPP and PLA Properties for Application in Food Packaging

This paper compares the properties of iPP based composites and PLA based biocomposites using 5% of ZnO particles or ZnO particles coated with stearic acid as filler. In particular, the effect of coating on the UV stability, thermostability, mechanical, barrier, and antibacterial properties of the polymer matrix were compared and related to the dispersion and distribution of the loads in the polymer matrix and the strength of the adhesion between the matrix and the particles. This survey demonstrated that, among the reported systems, iPP/5%ZnOc and PLA/5%ZnO films are the most suitable active materials for potential application in the active food packaging field

Characterisation of the Chitosan/layered silicate nanocomposites

Characterization of chitosan/layered silicate nanocomposites obtained by solution-mixing technique, having different compositions including treated and untreated montmorilonite (MMT) has been performed. The optimum amount of MMT and also the effect of nanoparticles type on nanocomposite properties by DSC, X-ray diffraction and TG measurements have been established. The chitosan chains were inserted into silicate layers to form the intercalated nanocomposites. The interlayer distance of the silicates in the nanocomposites enlarged as their amount increased. The stiffness and thermal stability enhanced

Effects of PP-based Nanopackaging on the Overall Quality and Shelf Life of Ready-to-eat Salami

A total of 1% nanoclay containing polypropylene ( PP)-nanocomposite and 1% nanoclay plus 5% poly-beta-pinene (P beta P) containing PP-active-nanocomposite materials were produced and tested for packaging of sliced salami. The sliced salami was packaged using both nanofilms and multilayer film of PP/PA/EVOH/PE under vacuum, modified atmosphere packaging under 50% CO2 and 50% N-2 and air and stored at 4 degrees C for 90 days. During storage, headspace gas composition; microbial, physical and chemical analyses; and sensory evaluation were performed. The antimicrobial effect of P beta P containing nanomaterial was pronounced under vacuum, and no bacterial growth was observed for 75 days. An a* value decreased notably in all applications during storage and preserved best by the multilayered material under vacuum and high CO2. Thiobarbituric acid reactive substances (TBARS) were 0.63 mg MDA/kg after the processing and gradually increased at all applications during increased storage. TBARS values of all vacuum applications were lower than that of modified atmosphere packaging applications. Rancid taste development was determined by sensory panelists when TBARS values were higher than 0.80 mg MDA/kg on the 90th day. There was no significant moisture loss, and no increase in hardness was determined during the whole storage time. The longest shelf life was 75 days for the sliced salami under vacuum and high CO2 using the multilayer material. P beta P containing nanomaterial provided 50 days of shelf life under vacuum, which is commercially considerable. Copyright (C) 2017 John Wiley & Sons, Ltd

Development of Antibacterial Composite Films Based on Isotactic Polypropylene and Coated ZnO Particles for Active Food Packaging

This study was aimed at developing new films based on isotactic polypropylene (iPP) for food packaging applications using zinc oxide (ZnO) with submicron dimension particles obtained by spray pyrolysis. To improve compatibility with iPP, the ZnO particles were coated with stearic acid (ZnOc). Composites based on iPP with 2 wt % and 5 wt % of ZnOc were prepared in a twin-screw extruder and then filmed by a calender. The effect of ZnOc on the properties of iPP were assessed and compared with those obtained in previous study on iPP/ZnO and iPP/iPPgMA/ZnO. For all composites, a homogeneous distribution and dispersion of ZnOc was obtained indicating that the coating with stearic acid of the ZnO particles reduces the surface polarity mismatch between iPP and ZnO. The iPP/ZnOc composite films have relevant zinc oxide with respect to E. coli, higher thermal stability and improved mechanical and impact properties than the pure polymer and the composites iPP/ZnO and iPP/iPPgMA/ZnO. This study demonstrated that iPP/ZnOc films are suitable materials for potential application in the active packaging field

Application of Polypropylene-Based Nanocomposite Films for Sliced Turkish Pastrami under Vacuum/Modified Atmosphere Packaging: A Pilot Study

The purpose of this study was to investigate the effects of polypropylene (PP)-based nanomaterials with improved barrier properties by nanoclay and antimicrobial properties by poly-beta-pinene (PβP) on the quality and shelf life of sliced pastrami as an alternative to the commercial multilayered materials. Sliced pastrami was packaged using nanocomposite films with and w/o PβP, and multilayered material under air, modified atmosphere packaging (MAP) and vacuum. Packaged products were screened for microbiological, physicochemical and sensory quality at 4 °C for 6 months. Salmonella spp., Clostridium perfringens and coagulase positive Staphylococus aureus were not detected in the products during entire storage. No yeast and mold growth occurred for entire storage using antimicrobial nanocomposite and multilayer material under vacuum. The antimicrobial effect of PβP on the pastrami was higher under vacuum compared to MAP applications suggesting that direct contact of the material is required with the food surface. Thiobarbituric acid reactive substances (TBARS) of pastrami under vacuum were lower than those of MAP applications. The initial carbonyl content of the product was determined as 3.38 nmol/mg and a slight increase was observed during storage period for all applications. The shelf life of pastrami is suggested as 150 days using PβP containing nanomaterials under vacuum, which is longer than the shelf life of a commercial product on the market using multilayer materials

Effect of electron beam irradiation on the properties of polylactic acid/montmorillonite nanocomposites for food packaging applications

This study was aimed at (1) developing new films based on polylactic acid/montmorillonite (PLA/MMT) with improved properties for applications in the food packaging industry and (2) analyzing the effect of electron-beam (eBeam) radiation on the structural, morphological, mechanical, and barrier properties of these nanomaterials. Nanocomposites based on PLA with 1, 3, and 5 wt % of MMT were prepared in a twin-screw extruder and then filmed by a calender. The nanocomposites were exposed to eBeam doses; one set at 1 kGy dose and the other at 10 kGy dose. The effect of MMT addition and of eBeam radiation on the properties of PLA were assessed. For all composites, a homogeneous distribution and dispersion of MMT in the PLA matrix was obtained. All nanocomposites showed an increase of the mechanical and oxygen-barrier properties compared to neat PLA. The eBeam irradiation caused an increase of the crystallinity, formation of crosslink, increase of the glass-transition temperatures, and enhancement of the yield values in the stress-strain curves for all nanocomposites. This study demonstrated that PLA/MMT films are suitable materials for eBeam processing of prepacked food at the realistic doses that were employed in this study. © 2015 Wiley Periodicals, Inc