Cultivar effect on the phenolic composition and antioxidant potential of stoned table olives

Abstract

Stoned green table olives "alcaparras" prepared from five different cultivars (Cv. Cobrançosa, Madural, Negrinha de Freixo, Santulhana and Verdeal Transmontana) were investigated concerning their phenolic composition and antioxidant potential. From each cultivar, five independent lots were prepared. The phenolic profile was determined by HPLC/DAD at 280 nm, and antioxidant potential measured using the reducing power and scavenging effect on DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals assays. Twelve phenolic compounds were identified, being hyrdoxytyrosol the most abundant one, followed by verbascoside and tyrosol. Cv. Cobrançosa and Santulhana reported higher content of phenolic compounds, with 165.76 and 163.66 mg/kg of fresh "alcaparras" table olives, respectively. Regarding antioxidant activity, Cv. Santulhana and Cobrançosa showed higher EC(50) values, lower than 1.40 and 0.48 mg/mL for reducing power and DPPH methods, respectively. Significant negative correlations were obtained between olive phenolics and EC(50) values from the antioxidant activity. The direct contact of the pulp with water, characteristic of this processing method, eliminates important hydrossoluble compounds, being the cultivar used an important determinant for the final "alcaparras" composition in terms of ingested phenolic compounds and antioxidant activity.