Poly(ε-caprolactone) nanofibers functionalized with poultry feather hydrolysate as a novel antioxidant material†

Bioactive keratin hydrolysates obtained from microbial treatment of poultry feathers were incorporated into polycaprolactone (PCL) nanofibers using the electrospinning method. The nanofiber mats were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, thermal analysis, and hemolysis rate. Feather keratin hydrolysate (FKH) was effectively incorporated into the nanofibers, and the antioxidant activity of the nanomaterials was confirmed. The SEM analysis revealed the formation of fibers with typical string-like morphology and nanometric size. The average diameter of nanofibers containing 1, 2.5 and 5% FKH was 348, 363 and 533 nm, respectively. FTIR spectra showed no relevant interactions between the hydrolysate and the polymer during the electrospinning process, and the FKH addition caused no important modifications on the thermal properties of the nanofibers such as thermal degradation rate, melting temperature, and crystallinity, which were investigated using TGA and DSC techniques. Furthermore, the functionalized nanofibers showed low hemolysis rates (up to 3%) suggesting they are safe materials when considering the acceptable hemolysis threshold for biocompatible materials (below 5%). Preliminary tests revealed that FKH can be released from the nanofibers in food simulant solutions. Considering these results, the electrospun PCL nanofibers are promising candidates for incorporation of bioactive feather hydrolysates with potential application as food packaging materials.