Comparison of whey protein particles and emulsions for the encapsulation and protection of α-tocopherol

Food proteins have been widely used for the preparation of emulsion-based carriers and lipid-free carriers. In this study, whey protein isolate (WPI)-alpha-tocopherol particles and emulsions were prepared at protein's concentrations from 0.5% to 5.0% and initial concentrations of alpha-tocopherol similar to 0.06% and 0.12%. Concentration of alpha-tocopherol affected the size of WPI particles but not that of WPI emulsions. zeta-Potential of WPI particles was greater than that of WPI emulsions. Encapsulation efficiency of alpha-tocopherol was greater in the emulsions than in the particles, but not at 0.12% alpha-tocopherol and 5.0% WPI. Storage stability of alpha-tocopherol was better in WPI emulsions than particles at 25 degrees C and at the intermediate stage of 45 degrees C but contrary at the ending of storage at 45 degrees C. The data gathered here should be useful for the development of protein-based carrier systems for hydrophobic components.