Development of Biodegradable Whey-Based Laminate Functionalised by Chitosan–Natural Extract Formulations

Abstract

In this research, antimicrobial polysaccharide chitosan and natural extracts were used as surface coating of a plastic laminate with an integrated whey layer on the inside. The aim was to establish the biodegradable and active concept of packaging laminates. For this purpose, chitosan nanoparticles (CSNPs) with embedded rosemary or cinnamon extracts were synthesised and characterised. Additionally, a whey-based laminate was functionalised: i) chitosan macromolecular solution was applied as first layer and ii) cinnamon or rosemary extracts encapsulated in CSNPs were applied as upper layer (layer wise deposition). Such functionalised whey-based laminate was physicochemically characterized in terms of elemental surface composition, wettability, morphology and oxygen permeability. The antimicrobial activity was tested against Staphylococcus aureus, Escherichia coli, Aspergillus flavus and Penicillium verrucosum. The antioxidant properties were determined using the ABTS assay. It could be shown that after functionalization of the films with the above-mentioned strategy, the wettability was improved. Furthermore, such whey-based laminates still show excellent barrier properties, good antimicrobial activity and a remarkable antioxidative activity. In addition to the improved biodegradability, this type of lamination could also have a positive effect on the shelf-life of products packaged in such structured films.

Two-Layer Functional Coatings of Chitosan Particles with Embedded Catechin and Pomegranate Extracts for Potential Active Packaging

“…The band of FTIR spectra of PE ( Figure 2 a, labeled in black) at 2915 cm −1 is assigned to CH 2 asymmetric stretching, the band at 2848 cm −1 corresponds to CH 2 symmetric stretching, while bending deformation and rocking deformations are observed at 1463 and 718 cm −1 . Details of the FTIR spectrum of PP are presented in Figure 2 b, where the bands at 2950, 2917, 2867, 2842, 1458, 1376, 1167, 997, and 973 cm −1 are assigned to CH 3 stretching, CH 2 asymmetric stretching, CH 2 symmetric stretching, CH 2 symmetric stretching, CH 2 bending vibration, CH 3 bending vibration, CH 3 symmetric deformation vibration, CH 3 rocking vibration, and CH 2 rocking vibration, respectively [ 25 , 27 ].…”

“…For all oxygen plasma pre-activated foils, the OTR (cm 3 /m 2 ·24 h) was reduced to around zero value (i.e., a real, almost complete oxygen barrier), providing an ideal scenario for the development of an active packaging concept. Oxygen permeability around the value zero can often only be achieved by plastic laminates of 3 to 7 layers [ 25 ] or by metallization processes and aluminum oxide coatings [ 45 , 46 ], which are somehow environmentally controversial; therefore, these results represent a great success.…”

“…The first layer was prepared from a macromolecular chitosan solution, and provides, as already shown, excellent antibacterial properties, while the second (upper) layer contains a nano-disperse network of polyphenol extracts embedded in chitosan nanoparticles to provide antioxidant and antimicrobial properties. Several concepts have already been presented by us, where a clear state-of-the-art method was discussed as well [ 24 , 25 , 26 , 27 ]. However, chitosan particles with incorporated phenol catechin and pomegranate extract, respectively, as a second coating layer, backed by this research methodology, have not been presented thus far.…”

Incorporation of Metal-Based Nanoadditives into the PLA Matrix: Effect of Surface Properties on Antibacterial Activity and Mechanical Performance of PLA Nanoadditive Films

“…The antimicrobial activity of PLA films and PLA-NPs composite films against the bacteria Escherichia coli (DSM 1576) and Staphylococcus aureus (DSM 799) was determined according to the internal protocols of the Department of Microbiological Research, Center for Medical Microbiology of the National Laboratory for Health, Environment, and Food in Maribor, No. P96 ‘Biofilm production on various materials Staphylococcus aureus ’ P90 (ISO22196) for determination of microbiological activity/antimicrobial activity of plastic surfaces, reported in our previous works, and they are standardized methods known for plastic surfaces [ 86 , 87 ]. More specifically, the PLA, PLA-NPs composite films of size 10 mm × 10 mm were exposed to the standardized medium inoculated with Escherichia coli and Staphylococcus aureus and set at 0.5 on the McFarland scale.…”

Disposable Food Packaging and Serving Materials—Trends and Biodegradability

“…Lower water sorption can be also obtained by the addition of polyvinyl alcohol [ 227 ], while mechanical resistance and water vapor barrier can be improved by the application of colloidal nano-silica [ 228 ]. Antimicrobial and antioxidant activity of the whey-based materials can be improved by the incorporation of water-soluble chitosan [ 229 ], chitosan nanoparticles with rosemary or cinnamon extracts [ 230 ], lysozyme with polyacrylic acid [ 231 ], or Fucus vesiculosus L. extract [ 232 ].…”