In our study we developed the edible chitosan and alginate coatings with turmeric or oregano additives. The objective of the research was to evaluate the dose-dependent cytotoxicity of films. In cell line studies on HepG2 and BJ cells, they were shown to be non-cytotoxic materials (IC50% was not reached). For HepG2 increase in cell proliferation was observed for 3, 4, and 7 mg/mL of OS3 (124,79±9,21; 162,4±10,46; 165,37±18,44) after 72 h. In BJ cells, no significant decrease in proliferation was noted after 24- and 48-hour exposure to OS0 and OS1 (1-7 mg/ml). The addition of oregano (1% v/v) resulted in films with higher elongation at break and 40% higher tensile strength compared to the base (OS0) film. Use of additives significantly increased the thermal stability of the complexes (by an average of 10 °C). Coatings were tested on tofu and had proven potent antimicrobial properties.
Although much research has been performed on DNA complexes carrying long alkyl chains (C10, C16, and C18), there is no information about physicochemical characterization of synthesized composites with allyl imidazole-based ionic liquids and quaternary ammonium salts with n-butyl chains. Here, complexes were synthesized by ion-exchange reactions between sonicated DNA and three ionic liquids (ILs) formed from two imidazole-based compounds, 1-allyl-3-methylimidazolium bromide (Amim) or 1-butyl-3-methylimidazolium bromide (Bmim), and from the quaternary ammonium salt tetra-n-butylammonium bromide (TBAB). Signals in UV–Vis, IR, and CD spectra indicating inclusion of small molecules into the DNA structure confirmed the formation of DNA complexes. Both IR and CD spectra indicated that the B-form conformation of the DNA did not change after the formation of the complexes. Similarly, X-ray diffraction patterns revealed that the formation of IL–DNA complexes did not change the structure of native B-form DNA. Molecular weight (Mw) and radii of gyration (Rg) values of IL–DNA complex chains, established by high-performance size exclusion chromatography coupled with multiangle-laser light-scattering with a differential refractive index detector, were significantly lower than those values found for native DNA molecules due to DNA fragmentation by sonication during complex formation and the direct effects of the IL on the DNA. Scanning electron microscopy images indicate the formation of nanofibres in DNA-Amim and DNA-Bmim complexes, whereas the formation of nanowires was found in samples of DNA-TBAB complexes. Changes in optical properties confirmed by UV and photoluminescence make DNA–IL complexes potential candidates for biosensor application.
The aim of this study was to analyze the functional properties of newly obtained films based on sodium alginate and lecithin with the addition of antioxidant-rich coffee extracts and to verify their potential as safe edible food packaging materials. In our study, we developed alginate–lecithin films enriched with green or roasted coffee bean extracts. The roasting process of coffee beans had a significant impact on the total phenolic content (TPC) in the studied extracts. The highest value of TPC (2697.2 mg GAE/dm3), as well as antioxidant activity (AA) (17.6 mM T/dm3), was observed for the extract of light-roasted coffee beans. Films with the addition of medium-roasted coffee extracts and baseline films had the highest tensile strength (21.21 ± 0.73 N). The addition of coffee extract improved the barrier properties of the films against UV light with a decrease in the transmittance values (200–400 nm), regardless of the type of extract added. Studies on Caco-2, HepG2 and BJ cells showed that digestated films were non-cytotoxic materials (100–0.1 μg/cm3) and had no negative effect on cell viability; an increase was noted for all cell lines, the highest after 48 h in a dose of 1 μg/cm3 for a film with medium-roasted coffee (194.43 ± 38.30) for Caco-2. The tested films at 20% digestate concentrations demonstrated the ability to reduce nitric oxide (NO) production in the RAW264.7 cell line by 25 to 60% compared to the control. Each of the tested films with coffee extracts had growth inhibitory properties towards selected species of bacteria.