Abstract: α-Tocopherol/casein nanoparticles were prepared by self-assembly and their stability was assessed. The binding strength between α-tocopherol and casein was evaluated by fluorescence intensity. The composite nanoparticles were characterized and the retention rate of α-tocopherol was used as an indicator to evaluate its stability. The results indicated that the optimum conditions for preparing α-tocopherol/casein nanoparticles were as follows: 37 ℃, pH 6.8 and α-tocopherol/casein mass ratio of 1:300. The nanoparticles prepared using the optimized conditions showed an average diameter of (135.6 ± 13.7) nm, an encapsulation efficiency of (97.97 ± 7.38)% and a drug loading of (0.33 ± 0.03)%. Strong hydrogen bonds existed between α-tocopherol and casein as indicated by Fourier transform infrared spectroscopy analysis. The nanoparticles were uniform in size and regularly spherical in shape and had good dispersibility. Compared with α-tocopherol, the nanoparticles showed better stability to storage, high temperature, lyophilisation and oxidation. The α-tocopherol/casein nanoparticles could effectively improve the stability of α-tocopherol, thereby having a wide scope of application and showing promise in the food industry.

Key words: α-tocopherol, casein, nanoparticles, self-assembly