Food bioactive-loaded colloidal particles were designed for entrapment and long-term protection of a model of heat-and light sensitive vitamin with antioxidant activity (a-tocopherol), by using GRAS ingredients capable of forming macromolecular assemblies (1-2). Vitamin matrix carriers were formed from aqueous dispersions of colloidal particles consisting in heat- and high pressure-induced protein aggregates, and protein-stabilised oil-in-water nanoemulsions (100-500 nm), followed by quick removal of aqueous solutions by spray drying. They were characterised for vitamin-loading efficiency and long-term stability against chemical degradation and the results were discussed in regards with particle composition and structure-forming properties as related to processing factors before and after spray drying.
Our results indicated that differences in the degree of vitamin protection toward chemical degradation could be due to differences in particle morphology and wall and surface structures, as observed from different experimental approaches. Data obtained from static and dynamic light scattering, fluorescence spectroscopy, differential scanning calorimetry, confocal laser and scanning electron microscopes, showed that hydrophobic vitamin molecules could be entrapped into lipid particle cores, attached to the protein-containing wall materials and also in protein aggregates formed by non adsorbed proteins. The higher level of vitamin protection was observed for mother protein-stabilised nanoemulsions containing lower size lipid droplets and less non adsorbed protein aggregates. These results indicated that vitamin-loaded particles prepared by spray drying are greatly affected by other processing factors and particularly by particle size characteristics of mother liquid dispersions.
Research superviser: Prof. Perla Relkin perla.relkin@agroparistech.fr
References
(1) Shukat R, & Relkin P. Lipid nanoparticles as vitamin matric carriers in liquid food systems: on the role pf high-pressure homogenisation, droplet size and adsorbed matherials, Colloids & Surfaces B: Biointerfaces, 86 (2011)119-124.
(2) Perla Relkin, Rizwan Shukat, Food protein aggregates as vitamin-matrix carriers: Impact of processing conditions, Food Chemistry, 134 (2012) 2141–2148.
Acknowledgements
Gabriele Moulin is warmly acknowledged for their assistance in laser confocal microscope
