Physicochemical, Structural, Molecular, and Thermal Characterization of Fucus vesiculosus Extract-Based Nanofibrous...

Ratios of 3:1 and 4:1 Fucus vesiculosus:zein (FV:Z) containing nanofibrous mats were designed for the first time by the electrospinning method. According to the results, electrical conductivity, surface tension, viscosity, and density are proportional to each other. Scanning electron microscopy (SEM) images depicted morphology, revealing the presence of homogeneous nanostructures. Changing the polymer ratios altered the fiber diameter, specific surface area, pore volume, and pore size. Average values of hydroxycinnamic (21.5 μgmg^-1), quercetin (19.8 μgmg^-1), and caffeic (16.23 μgmg^-1) were determined to be the highest phenolic compounds in the HPLC chromatogram, serving as an important source of bioactive ingredients for food applications. Total IC50 values of FV:Z 3:1 and FV:Z 4:1 mats were 46.37 μgml^-1 and 46.90 μgml^-1, respectively. Total phenolic content (TPC) is also presented at higher levels in all of the ABTS and DPPH assays. Determination of the H atom in the -OH group and the carbonyl group of a carboxylic acid group of phenolic acid in the FTIR spectrum was consistent with the ABTS and DPPH results. In the FTIR spectra for nanofibrous mats, vibrations shifted toward smaller wavenumbers with stronger ionic interaction compared to the FV extract. Slightly shifted and increased peaks were observed in the spectra, confirming successful interaction between Fucus and zein. Functional groups (NH₂, COOH, and OH) allow intermolecular interactions such as H bonding. π-π stacking, π alkyly, and sulfur-containing products are detected. TGA and DSC results showed that the thermal stability of nanoencapsulated FV bioactive compounds strengthened at higher temperatures. Differences in XRD crystal patterns, such as changes in the intensities of diffraction peaks, were also recognized between samples. Overall, stability and bioactivity improved with the formation of inter/intramolecular associations. Results indicated that nanofibrous mats have potential in the nanoencapsulation and delivery of bioactives.