Ultrasonic-Assisted Preparation of α-Tocopherol/Casein Nanoparticles and Application in Grape Seed Oil Emulsion

Abstract

In this work casein (CN) was used as a carrier system for hydrophobic agent α-tocopherol (α-TOC), an amphiphilic self-assembling micellar nanostructure was formed with ultrasound-assistance. The interaction mechanism was detected by UV-Vis spectroscopy, Fluorescence spectroscopy and Fourier transform infrared spectroscopy (FTIR), the stability of the nanoparticles was investigated by the typical processing and storage conditions. Oil-in-water emulsion containing self-assembled nanoparticles was prepared with grape seed oil, the effect of emulsion oxidation stability was studied with the professional rancimat. Results showed that UV-Vis spectra of α-TOC/CN nanoparticles complexes were significantly different during ultrasonic treatments, which indicate an increase in its interation. Interaction between α-TOC and casein at different molar concentrations resulted in a quenching of the intrinsic fluorescence at 280 nm and 295 nm. Moreover, by using FTIR deconvolution analysis and multicomponent peak modeling, the relatively quantitative amounts of α-helical and β-sheet in protein secondary structure were obtained, the self-assembly nanoparticles can improve stability of α-TOC by protecting from degradation caused by light and oxygen. Importantly, both the concentrations of α-TOC/CN nanoparticles were able to inhibit lipid emulsion oxidation.