Electrospun Pullulan/Hemp Protein Nanohybrids for Sustained Release of Phenylethanoid Glycosides

Innovative electrospun pullulan/hemp protein isolate nanofibers (PUL/HP) with lecithin were successfully formulated for the delivery of phenylethanoid glycosides (PGs) from Teucrium montanum extract, at PUL to HP ratios of 80:20, 70:30, 60:40, 50:50, 40:60, and 30:70, based on total polymer mass (w/w). A higher HP content led to a more elastic behavior, which was stimulated by a stronger entanglement between polymer and polypeptide chains. The biopolymers used showed favorable compatibility with the investigated PGs, achieving an encapsulation efficiency of over 80 %. The increased elastic behavior led to the formation of a bead-on-string morphology and a higher average diameter. The thermal stability of the loaded nanofibers was diminished by the presence of incorporated polyphenolic extract. Under simulated gastrointestinal conditions, a sustained release of total phenolic content from the delivery systems was achieved. According to the FTIR spectra, this is mainly due to the efficient interplay of hydrogen and hydrophobic interactions with the polyphenols within the polysaccharide-phospholipid-polypeptide structure. The circular dichroism spectra showed that the polyphenol extract was involved in the secondary HP structure, resulting in a rather random, uncoiled structure. These results provide a time- and cost-efficient approach to stabilize naturally immiscible biopolymers without crosslinking or emulsion preparation, while similarly altering the physicochemical properties of the drug delivery systems.