Non-reducing sugars, such as sucrose, have also been shown to inhibit carotenoid oxidation. A number of mechanisms have been proposed to account for the ability of sucrose to increase the chemical stability of astaxanthin in nanodispersions. Sucrose decreases the concentration of oxygen dissolved in the aqueous phase and increases the viscosity of the aqueous phase, leading to a decrease in the diffusion of reactive species to the droplet surface and acting as a free radical scavenger. However, reducing sugars have been shown to promote oxidation in aqueous colloidal dispersions (Huang, Kakuda, & Cui, 2001). The origin of this pro-oxidative effect is the ability of reducing sugars to reduce transition metal ions to their most active state. Any other type of food component that can act as a reducing agent for transition metals may also be effective at promoting oxidation (McClements & Decker, 2000).