Stabilisation of extra virgin olive oil-in-water emulsions prepared by citrus pectin using green tea and grape seed phenolic extracts and catechin

Abstract

This study aimed at the solution of stability problems of extra virgin olive oil rich (oil:aqueous phase ratio = 50:50) model oil-in-water emulsions prepared with pectin using green tea (GTE) and grape seed extracts (GSE), and (+)-catechin (CAT). Olive oil-in-water emulsion prepared with pectin at 0.5% (w/v) without phenolics lost 36% of its stability within 1 day. GTE at 1% (w/v) caused a limited increase in emulsion stability while emulsions with GSE at >= 0.25% or CAT at 1% maintained >90% of their stability after 14 days. GSE and CAT reduced the emulsion droplet size (2.6- and 1.9-fold) while GTE increased the emulsion droplet size (1.5-fold). Emulsions with GSE showed the smallest and most densely packed lipid droplets. The highest phenolic content and antioxidant activity in emulsions were obtained with CAT followed by GSE and GTE. This work is significant in that it showed the possibility of using GSE to obtain stable extra virgin olive oil emulsion-based functional foods.