Properties of poly (lactic acid) (PLA) and its nanocomposites, with silica nanoparticles (SiO2), as filler were investigated. Neat PLA films and PLA films with different percentage of hydrophobic fumed silica nanoparticles (0.2, 0.5, 1, 2, 3 and 5 wt. %) were prepared by solution casting method. Several tools were used to characterize the influence of different silica content on crystalline behavior, and thermal, mechanical and barrier properties of PLA/SiO2 nanocomposites. Results from scanning electron microscope (SEM) showed that the nanocomposite preparation and selection of specific hydrophobic spherical nano filler provide a good dispersion of the silica nanoparticles in the PLA matrix. Addition of silica nanoparticles improved mechanical properties, the most significant improvement being observed for lowest silica content (0.2wt.%). Barrier properties were improved for all measured gases at all loadings of silica nanoparticles. The degree of crystallinity for PLA slightly increased by adding 0.2 and 0.5 wt. % of nano filler.
Food packaging industry presents one of the fastest growing industries nowadays. New trends in this industry, which include reducing food as well as packaging waste, improved preservation of food and prolonged shelf-life together with substitution of petrochemical sources with renewable ones are leading to development of this industrial area in diverse directions. This multidisciplinary challenge is set up both in front of food and material scientists. Nanotechnology is recently answering to these challenges, with different solutions-from improvements in materials properties to active packaging solutions, or both at the same time. Incorporation of nanoparticles into polymer matrix and preparation of hybrid materials is one of the methods of modification of polymer properties. Nano scaled materials with antimicrobial properties can act as active components when added into polymer, thereby leading to prolonged protective function of pristine food packaging material. This paper presents a review in the field of antimicrobial nanomaterials for food packaging in turn of technology, application and regulatory issues.
The focus on sustainability and circular economy is leading to a need for development of new food packaging concepts, including recyclable materials that ideally consist of a single material in a monolayer system. This research was focused on the possibility of replacing complex multilayered material [amorphous polyethylene terephthalate/polyethylene (APET/PE)] with simple recyclable mono material [high‐density polyethylene (HDPE)] for packaging of chicken fillets in modified atmosphere packaging (CO2/N2: 60%/40%). Bacterial growth measured as total viable count (TVC), lactic acid bacteria and Enterobacteriaceae, Brochothrix thermosphacta and Escherichia coli for chicken fillets packed in HDPE mono materials was compared with chicken fillets packed in APET/PE.TVC increased during the storage period (24 days) with high level of TVC count (7 log10 CFU/g) recorded at Days 19–20 of storage in both HDPE and APET/PE material. No significant differences were recorded in off‐odour between chicken stored in APET/PE compared with HDPE in CO2/N2 atmosphere during the storage period (samples were regarded as acceptable on the 24th day of storage). The drip loss increased in all samples during storage, and no significant differences between samples stored in different materials were recorded.Significant differences in bacterial growth were recorded between samples with different gas volume to product volume (G/P) ratio (Day 17), implying that higher G/P ratio is resulting in lower TVC count. The lowest G/P ratio caused the highest drip loss, whereas addition of CO2 emitter reduced the drip loss to some extent.This research is very encouraging as it provides new insight into the use of monolayer materials as well as the importance of design for recycling in circular economy.
Poly(butylene succinate-co-butylene adipate) (PBSA)-based materials are receiving growing attention in the packaging industry for their promising biodegradability. However, poor gas barrier properties and low durability of biodegradable polymers, such as PBSA, have limited their wide-spread use in food packaging applications. Here we report a scalable solution to improve gas barrier properties and stabilize PBSA against photo-aging, with minimal modifications to the biodegradable polymer backbone by using a commercially available and biocompatible layered double hydroxide (LDH) filler. We investigate and compare the mechanical, gas barrier, and photoaging properties of PBSA and PBSA-LDH nanocomposite films produced on a pilot scale. An increase in rigidity in the nanocomposite was observed upon addition of LDH fillers to neat PBSA, which direct the application of neat PBSA and PBSA-LDH nanocomposite to different food packaging applications. The addition of LDH fillers into neat PBSA improves the oxygen and water vapour barriers for the PBSA based nanocomposites, which increases the attractiveness of PBSA material in food packaging applications. Through changes in the viscoelastic behaviour, we observe an improved photo-durability of photoaged PBSA-LDH nanocomposites compared to neat PBSA. It is clear from our studies that the presence of LDH enhances the lifetime durability and modulates the photodegradation rate of the elaborated biocomposites.
The influence of post-harvest ripening conditions of pepper Aleva NK picked in red maturity stage on the composition of volatiles in spice paprika was investigated by GCMS. The post-harvest ripening in the dark and under daylight was conducted under semicontrolled conditions for two weeks. The obtained chromatograms indicated that the aroma of investigated spice paprika consisted of a large number of volatile compounds regardless of the application and conditions of the post-harvest ripening. The main volatiles of the analyzed paprika samples were fatty acids and their esters, terpenes and terpenoides and aldehydes and ketones. The share of fatty acids and their esters decreased during the post-harvest ripening, and the ripening in the dark favored the decrease. The share of terpenes and terpenoides and the share of aldehydes and ketones in the total volatiles increased during the post-harvest ripening. The post-harvest ripening in the dark favored the increase of the share of terpenes and terpenoides, while the ripening under daylight favored the increase of the share of aldehydes and ketones.