Antioxidant capacity of the striped sunflower seed (Helianthus annuus L.) aqueous extract

The aim of this work was to study the aqueous extract of cotyledons derived from the striped sunflower seeds, with regard to the kinetics of its antioxidant capacity and its phenolic composition. The results showed that, among the phenolic compounds of this extract which were identified by gas chromatography, chlorogenic acid (12.88%) was the prevailing compound. The effectiveness of the aqueous extract in the beta-carotene/linoleate model system was estimated on the basis of the oxidation induction period, which was determined by the method of tangents to the two parts of this extract's kinetic curve, and the study showed that the extract antioxidants may be effective in blocking radical chain reactions and may also interfere with the reactions that produce the secondary products that speed up the system's oxidative process when present in higher concentrations (233.2 mu g/mL). The result found by the Rancimat (R) method showed that the aqueous extract at 300 [mu g/mL (15.2% IP) was comparable to the BHA standard at 100 mu g/mL (16.0 +/- 0.86%) in a lipidic system.