Electrosprayed whey protein nanocarriers containing natural phenolics; thermal and antioxidant properties, release behavior and stability

Abstract

Abstract In this study, a one-step and convenient electrospraying strategy was investigated to encapsulate olive leaf extract (OLE) within whey protein concentrate (WPC) nanoparticles and they were characterized via differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). Furthermore, the release properties, antioxidant activity, thermal/oxidative stability, and color profiles of the nanoparticles were also evaluated. WPC offered good capability in re-ordering into spherical nanoparticles and encapsulating OLE into its amphiphilic core. The DSC results suggested a higher denaturation and glass transition temperature (Tg) of WPC due to an increase in the concentration of phenolics and a reduction in the melting temperature compared with free OLE and WPC samples; the highest and lowest Tg values were corresponding to WPC (at 160\xa0°C) and WPC20OLE500 (at 140\xa0°C), respectively. The coated phenolics were completely and almost uniformly released into the medium of higher pH. The WPC30 sample (30% protein) had the highest free radical inhibition at both OLE levels (45.26 and 46.68%). The WPC30OLE500 with oxidative stability of 43.5\xa0h possessed the highest oxidative stability index. In conclusion, the electrosprayed WPC nanoparticles might be engineered as a promising nanodelivery cargo for promoting the release profile and thermochemical properties of bioactive agents.