In this thesis, stability and antioxidant activity of olive oil-in-water emulsions prepared with citrus pectin (CPEC) and pectins extracted from two fig cultivars (Sarılop: FPECn and Siyah Orak: FPECc) were evaluated in the presence of green tea (GTE) and grape seed extracts (GSE), and a basic monomeric flavonoid, (+) catechin (CAT). The emulsion stabilities of FPECn and FPECc between 0.125 and 1% (w/v) were comparable to those of CPEC. Control olive oil-in-water emulsions with 0.5% CPEC, FPECn or FPECc prepared without the addition of polyphenols lost 29 to 36% of their initial emulsion stability only within 1 day. The addition of GSE at 0.25 or 0.5% caused a considerable increase in the stability of emulsions prepared with CPEC at 0.5% (less than 10% loss in emulsion stability within 14 days) while GTE caused only a limited increase in the stability of CPEC emulsions. The CAT is the only polyphenol that caused significant increases in the stability of all pectin emulsions. In contrast, both GTE and GSE showed almost no effect in stability of FPECn and FPECc emulsions. The polyphenol added emulsions were characterized for their droplet size, zeta potential and viscosities. The CAT and GSE added emulsions showed significantly higher total phenolic content and antioxidant activity than GTE added emulsions during 14 days of storage. This thesis clearly showed that GSE and CAT stabilized CPEC emulsions, and CAT stabilized FPECn or FPECc emulsions have a great potential to develop novel antioxidant olive oil based functional foods.