Nanometals incorporation into active and biodegradable chitosan films.

This study investigates the effects of incorporating ZnO, TiO2, and colloidal Ag nanoparticles on the antioxidant, antimicrobial, and physical properties of biodegradable chitosan films. The research focuses on addressing the growing demand for sustainable packaging solutions that offer efficient food preservation while mitigating environmental concerns. In this investigation, the physical properties including thickness, water content, solubility, swelling degree, tensile strength, and elasticity of the chitosan films were examined. Additionally, the samples were analyzed for total polyphenol content, antimicrobial activity, and antioxidant capacity. Notably, the incorporation of ZnO nanoparticles led to the lowest water content and highest strength values among the tested films. Conversely, the addition of colloidal Ag nanoparticles resulted in films with the highest antioxidant capacities (DPPH: 32.202 ± 1.631 %). Remarkably, antimicrobial tests revealed enhanced activity with the inclusion of colloidal silver nanoparticles, yet the most potent antimicrobial properties were observed in films containing ZnO (E.coli: 2.0 ± 0.0 mm; MRSA: 2.0 ± 0.5 mm). The findings of this study hold significant implications for the advancement of edible biodegradable films, offering potential for more efficient food packaging solutions that address environmental sustainability concerns. By elucidating the effects of nanoparticle incorporation on film properties, this research contributes to the ongoing discourse surrounding sustainable packaging solutions in the food industry.

Nanoparticles and Plant By-Products for Edible Coatings Production: A Case Study with Zinc, Titanium, and Silver.

For the development of functional edible packaging that will not lead to rejection by the consumer, it is needed to analyze the interactions between ingredients in the packaging matrix. The aim of this study was to develop edible chitosan-based coatings that have been enriched with red grape extracts, zinc, silver, and titanium nanoparticles. The organoleptic properties of the produced edible packaging were described by quantitative descriptive analysis and consumer acceptability was verified by hedonic analysis. By image analysis, color parameters in the CIELab system, opacity, Whiteness and Yellowness Index were described. The microstructure was described by scanning electron microscopy. The hedonic evaluation revealed that the addition of nanometals and their increasing concentration caused a deterioration in sample acceptability. The overall evaluation was higher than 5 in 50% of the samples containing nanometals. The addition of nanometals also caused statistically significant changes in L*, a*, and b* values. The sample transparency generally decreased with the increasing concentration of nanoparticle addition. Scanning electron microscopy showed, that the addition of nanometals does not disrupt the protective function of the packaging. From a sensory point of view, the addition of ZnO nanoparticles in concentrations of 0.05 and 0.2% appeared to be the most favorable of all nanometals.

Influence of Technological Maturity on the Secondary Metabolites of Hemp Concentrate (Cannabis sativa L.).

During the last decade, the popularity of hemp products has been rising rapidly. Products containing cannabidiol (CBD) are of predominant interest. Traditional hemp products are frequently enriched by CBD due to their potential therapeutic effects. Cannabidiol occurs naturally in hemp juice together with other biologically active substances, such as terpenes, flavonoids, and stilbenoids. These constituents act synergistically. This study aimed to observe the influence of the hemp plant developmental stage on its chemical composition and antioxidant activity. The hemp plants were analyzed during three vegetative stages, i.e., before, during, and after flowering. The collected samples were evaluated using the following analyses: total polyphenolic content and profile, terpenoid and cannabinoid contents, and ferric reducing antioxidant power. The results revealed statistically significant differences between the samples in almost all set parameters. The optimal period for hemp harvest depends on desirable compounds, i.e., phenolic content is the highest before flowering, while the levels of cannabinoids and terpenoids are the highest during the flowering period.

Study of the influence of platinum, palladium and rhodium on duckweed (Lemna minor).

OBJECTIVES: Road traffic pollutants and the residues of cytostatics that are widely used in anti-cancer therapy are a significant sources of platinum group elements (PGE; Pt, Pd and Rh) in environment. These metals can migrate into sewage and thus pollute surface waters. The purpose of our study was to evaluate the effect of PtCl4 on the antioxidant and enzymatic activity of duckweed (Lemna minor), a bioindicator of the aquatic environment. METHODS: The study was performed using a 7-day conventional test based on the OECD 221 (CSN EN ISO 20079)--Lemna sp. Growth Inhibition Test. We also conducted a microbiotest to analyse the effects of PtC4, PdCl2 and RhCl3 on the morphology and vegetative growth of colonies of this plant and compared their inhibitory effects during the microbiotest. RESULTS: We observed inhibition of colony growth and clear morphological changes. Antioxidant and enzymatic activities increased with platinum doses increased. The 168hEC50 of PtCl4 was 12.16 µM (95% confidence interval = 9.88-14.44) and the 168hEC50 of PdCl2 was 50.39 (95% confidence interval = 23.83-76.96). The greatest inhibition of growth by RhCl3 was observed at 25 µM. CONCLUSIONS: The obtained results suggest that L. minor phytotoxicity tests should be widely used in the biomonitoring.

Impact of platinum group elements on the soil invertebrate Folsomia candida.

OBJECTIVES: Trace concentrations of the platinum group elements (PGE; Pt, Pd and Rh) are nowadays an irreplaceable part of environmental analysis and assessment. These rare elements are used as effective substances in automotive catalysts to reduce pollution by emissions originating from fuel combustion. Due to their harmful potential, it is necessary to monitor their content and behaviour in different samples. Effect assessment using ecotoxicological bioassays with organisms at different trophic levels can provide valuable pieces of information on the risk of chemical substances in the ecosystem. DESIGN: The experiments were carried out as described in the OECD Guideline 232 [CSN ISO 11267 - Soil quality - Inhibition of reproduction of Collembola (Folsomia candida) by soil pollutants]. The reproductive effects of palladium (PdCl2) and rhodium (RhCl3) were examined. Concentrations of PGE tested were as follows: 5, 10, 25, 50 and 100 µmol.L-1. The EC50 (medium effective concentration) was determined after 28 days of exposure. Inhibition of reproduction of PGE-exposed collembolans was compared against controls. RESULTS: Values of 28dEC50 of PdCl2 and RhCl3 amounted to 21.0 µmol.L-1 and 266.22 µmol.L-1, respectively. We can confirm that the relative order of toxicities is Pd (II) > Pt(IV) >> Rh(III). CONCLUSION: To the best of our knowledge, this is the first study to use Folsomia candida as an indicator species to assess the risk of soil contamination by palladium and rhodium. However, more toxicity data for various species are needed to evaluate the environmental risks of PGEs in soils.

Comparison of the effect of platinum on producers in aquatic environment.

OBJECTIVES: An enhanced worldwide application of platinum group elements (PGE), in particular platinum, has been observed during recent decades. An increased concentration of PGE was determined in collected samples of great amount of aqueous ecosystems.The aim was to compare phytotoxic effect of platinum (PtCl4) by performing two different bioassays on green algae Pseudokirchneriella subcapitata and macrophyte duckweed, Lemna minor. MEDTHODS: The algal experiment (Pseudokichneriella subcapitata) followed OECD 201, the concentration row for PtCl4 was: 0.05; 0.01; 0.25; 0.5; 1 µM. The duckweed (Lemna minor) experiment was conducted according to OECD 221, employed PtCl4 concentrations were: 5; 10; 25; 50; 100 µM. Plants were cultivated as a microbiotest, using micro-volumes. RESULTS: The results of the algal test showed significant growth inhibition of the final biomass. The values of 72hEC5(µ), 72hEC10(µ), 72hEC20(µ) counted on a basis of average specific growth rate (µ) were 0.31 µM, 0.58 µM and 1.12 µM of PtCl4, respectively. The values, obtained on a basis of the area under the growth curves (A), were 0.04 µM (72hEC5(A)), 0.24 µM (72hEC10(A)) and 0.64 µM (72hEC20(A)). The experiment with duckweed showed 50% of growth inhibition and the values of 168hEC50(µ) were 19.55 µM and 168hEC50(A) 13.63 µM of PtCl4. CONCLUSION: The fronds of duckweed showed strong adverse effect of platinum influence (chlorosis, necrosis). The algal test and the estimation of 72hEC5(A) appears to be the most sensitive.

Impact of platinum on the soil invertebrate Folsomia candida.

OBJECTIVES: Regarding the environmental pollution, platinum group elements (PGE) are in the centre of interest of current research. These rare elements are used as effective substances in automotive catalysts to reduce pollution by emissions originating from fuel combustion. Due to their harmful potential, it is necessary to monitor their content and behaviour in different samples. Comprehensive studies on PGE behaviour and effects are still lacking. Their distribution in the food chain and data on bioaccumulation has not been described so far. METHODS: We focused on reproductive effects of platinum (PtCl4), in particular. Our study is based on a collembolan laboratory breed, test optimalization and validation according to the OECD 232 standards [CSN ISO 11267 - Soil quality - Inhibition of reproduction of Collembola (Folsomia candida) by soil pollutants]. The concentrations of PtCl4 tested were as follows: 5, 10, 25, 50 and 100 µM. The EC50 was determined after 28 days of testing. RESULTS: The results were evaluated using the inhibition of reproduction compared with controls. The EC50 was determined after the 28-day test. The value of 28dEC50 of the boric acid test was estimated at 120 mg/kg and the measured 28dEC50 of PtCl4 was 200.4 µM. CONCLUSION: The presented data can be considered as a step forward in the assessment of the potential risk of platinum in the terrestrial environment. However, more toxicity data for various species are needed to evaluate the environmental risk of platinum in soils.