Unravelling the role of sodium chloride and hydroxytyrosol on the colloidal properties and oxidative stability of olive oil-based o/w emulsions: A multivariate statistical approach

The individual and combined effect of sodium chloride and hydroxytyrosol on the colloidal properties and the chemical and physical stability of olive oil-in-water emulsions was explored by multivariate statistical analysis. Sodium chloride affected the dispersion degree of the emulsions causing an increase of droplet size and inducing flocculation phenomena; however, during storage, the presence of hydroxytyrosol, when added in combination with 2% and 5% of NaCl, retarded samples physical destabilization. A protective effect of salt on lipid hydroperoxides, over storage, was highlighted, mainly at the highest concentrations used. The analysis of volatile organic compounds allowed to identify different oxidation patterns as a consequence of NaCl addition and hydroxytyrosol; moreover, by applying a multivariate statistical approach, it was possible to highlight a positive effect of both NaCl and hydroxytyrosol over the reduction of some oxidation volatiles.