Chapter Six - Dynamic light scattering (DLS) of nanoencapsulated food ingredients

Abstract

Dynamic light scattering (DLS) refers to the measurement and interpretation of light scattering due to the Brownian motion of particles in a suspension. The DLS technique can be used for the characterization of particles/molecular sizes, particle size distribution, and relaxations in complex fluids using the Stokes-Einstein relationship. Nanoparticles have unique physical and chemical properties, which are mainly related to their particle size in some applications. The accuracy of this quantification in colloidal suspensions by DLS for food applications is very important because of the toxicity and exposure levels of nanoparticles. Other techniques are also available for characterization of colloidal particles (e.g., microscopy, spectroscopy and the recent addition of magnetic resonance), but they are more complex than DLS due to the difficulty of sample preparation, instrument-operating procedures, and statistical analysis. Therefore, in the current chapter, we depict the fundamental theory of DLS and the application of this technique for characterization of nanomaterials in special nanoencapsulated food ingredients. This text will attempt to interpret and understand DLS data and summarize the main studies using DLS for food nanoparticle applications. Finally, we present some results regarding the characterization of vitamin D3 and folic acid into chitosan nanoparticles.