Emulsifiers from olive stones

Abstract

Emulsifiers have been extracted from the alcohol-insoluble solids of olive (Olea europaea L.) stones. The extracts containing proteins and carbohydrates were characterized by dynamic light scattering, zeta potential measurements, Fourier transform infrared spectroscopy (FT–IR), Gas chromatography coupled with mass spectroscopy GC–MS, and size exclusion chromatography (SEC). The FT–IR and SEC data agree that the extracts have two macromolecular structural components: a polysaccharidic and a proteinic population. Experiments have been conducted as to evaluate the extracts' ability to emulsify oil-in-water emulsions, using confocal laser scanning microscopy for the examination of the microstructure, and static light scattering for the determination of droplets/flocs size distributions. The extracts are adequate emulsifiers for neutral model emulsions, providing stability against coalescence for 14 days. The interfacial characteristics of the extracts’ components (interfacial composition/topology and dynamic interfacial tension) have been examined as to complement the composition, emulsification and emulsion stability data. This work concludes that olive stones, the main by-products of olive processing, have the potential to act as sources of high added-value emulsifiers.