Propolis is one of the bee products, with multiple biological properties used in numerous applications. The research objective was to determine the chemical composition and biological properties (antibacterial, antifungal, antiviral, antioxidant, and cytoprotective activity) of propolis extracts collected from various regions of Poland. The results indicated that the total content of phenols (116.16–219.41 mg GAE/g EEP) and flavonoids (29.63–106.07 mg QE/g EEP) in propolis extracts depended on their geographic origin. The high content of epicatechin, catechin, pinobanksin, myricetin, and acids: vanillic and syringic in propolis samples was confirmed by chromatographic analysis. Moreover, the presence of caffeic acid phenethyl ester was confirmed in all samples. The origin of propolis also influenced the biological properties of its extracts. The propolis extracts were characterized by moderate DPPH free radical scavenging activity (29.22–35.14%), and relatively low ferrous iron chelating activity (9.33–32.32%). The results indicated also that the propolis extracts showed high activity in the protection of human red blood cells against free radicals generated from 2,2’-azobis(2-methylpropionamidine) dihydrochloride (AAPH). The extracts exhibited diversified activity against the tested pathogenic bacteria and limited activity against fungal strains. The research of selected propolis extracts showed that only 2 of 5 examined samples showed moderate activity against HPV (human papillomaviruses) and the activity depended on its geographical distribution.

Recently, the development of materials based on natural polymers have been observed. This is the result of increasing environmental degradation, as well as increased awareness and consumer expectations. Many industries, especially the packaging industry, face challenges resulting from legal regulations. Chitin is the most common biopolymer right after cellulose and is used to produce chitosan. Due to the properties of chitosan, such as non-toxicity, biocompatibility, as well as antimicrobial properties, chitosan-based materials are used in many industries. Many studies have been conducted to determine the suitability of chitosan materials as food packaging, and their advantages and limitations have been identified. Thanks to the possibility of modifying the chitosan matrix by using natural additives, it is possible to strengthen the antioxidant and antimicrobial activity of chitosan films, which means that, in the near future, chitosan-based materials will be a more environmentally friendly alternative to the plastic packaging used so far. The article presents literature data on the most commonly used natural additives, such as essential oils, plant extracts, or polysaccharides, and their effects on antimicrobial, antioxidant, mechanical, barrier, and optical properties. The application of chitosan as a natural biopolymer in food packaging extends the shelf-life of various food products while simultaneously reducing the use of synthetic plastics, which in turn will have a positive impact on the natural environment. However, further research on chitosan and its combinations with various materials is still needed to extent the application of chitosan in food packaging and bring its application to industrial levels.

Propolis is a natural bee product with various beneficial biological effects. The health-promoting properties of propolis depend on its chemical composition, particularly the presence of phenolic compounds. The aim of this study was to evaluate the relationship between extraction solvent (acetone 100%, ethanol 70% and 96%) and the antifungal, antioxidant, and cytoprotective activity of the extracts obtained from propolis. Concentrations of flavonoids and phenolic acids in the propolis extracts were determined using ultrahigh-performance liquid chromatography. The antioxidant potential of different extracts was assessed on the basis of 2,2-diphenyl-1-picrylhydrazyl (DPPH·) free-radical-scavenging activity, Fe³⁺-reducing power, and ferrous ion (Fe²⁺)-chelating activity assays. The ability of the extracts to protect human red blood cell membranes against free-radical-induced damage and their antifungal activity was also determined. The results showed that the concentration of flavonoids in the propolis extracts was dependent on the solvent used in the extraction process and pinocembrin, chrysin, galangin, and coumaric acid were the most abundant phenols. All extracts exhibited high antioxidant potential and significantly protected human erythrocytes against oxidative damage. On the other hand, the antifungal activity of the propolis extracts depended on the solvent used in extraction and the fungal strains tested. It needs to be stressed that, to the best of our knowledge, there is no study relating the effect of solvent used for extraction of Polish propolis to its phenolic profile, and its antifungal, antioxidant, and cytoprotective activity.

Cellulose nanocrystals were prepared using ionic liquids (ILs), 1-ethyl-3-methylimidazolium chloride [EMIM][Cl] and 1-propyl-3-methylimidazolium chloride [PMIM][Cl], from microcrystalline cellulose. The resultant samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The XRD results showed that nanocellulose obtained by treatment with both ILs preserved basic cellulose I structure, but crystallinity index of samples (except for Sigmacell treated with [EMIM][Cl]) was lower in comparison to the starting microcrystalline cellulose. The DLS results indicated noticeably smaller particle sizes of prepared cellulose for material treated with [PMIM][Cl] compared to cellulose samples hydrolyzed with [EMIM][Cl], which were prone to agglomeration. The obtained nanocellulose had a rod-like structure that was confirmed by electron microscopy analyses. Moreover, the results described in this paper indicate that cation type of ILs influences particle size and morphology of cellulose after treatment with ionic liquids.

In the last decade, an increasingly common method of maize stover management is to use it for energy generation, including anaerobic digestion for biogas production. Therefore, the aim of this study was to provide a chemical and structural characterization of maize stover fractions and, based on these parameters, to evaluate the potential application of these fractions, including for biogas production. In the study, maize stover fractions, including cobs, husks, leaves and stalks, were used. The biomass samples were characterized by infrared spectroscopy (FTIR), X-ray diffraction and analysis of elemental composition. Among all maize stover fractions, stalks showed the highest C:N ratio, degree of crystallinity and cellulose and lignin contents. The high crystallinity index of stalks (38%) is associated with their high cellulose content (44.87%). FTIR analysis showed that the spectrum of maize stalks is characterized by the highest intensity of bands at 1512 cm⁻¹ and 1384 cm⁻¹, which are the characteristic bands of lignin and cellulose. Obtained results indicate that the maize stover fraction has an influence on the chemical and structural parameters. Moreover, presented results indicate that stalks are characterized by the most favorable chemical parameters for biogas production.