Biochemical characterization and antioxidant activities of the edible part of globe artichoke cultivars grown in Tunisia

A renewed interest was observed recently in the globe artichoke as a promising source of polyphenols, a heterogeneous class of secondary metabolites characterized by various well-documented healthy properties. However, only few studies characterized Tunisian cultivars. Therefore, the present study aimed at evaluating the chemical parameters [fatty acids (FA), volatiles and phenolic derivatives content] in the edible part, the receptacle, of two globe artichoke cultivars ('Violet d'Hyéres' and 'Blanc d'Oran'), including their antioxidant activities. FA profiles of the receptacles showed that the most abundant acids were linoleic and palmitic ones. Forty-one volatile compounds, accounting for 97.6 - 96.3% of the receptacle aroma emission were identified. Sesquiterpenes hydrocarbons represented the main chemical class, in particular ?-selinene followed by ?-caryophyllene reached the highest levels in 'Violet d'Hyéres' (48.7% and 14.5%, respectively). Total phenols and tannins (P <= 0.05), o-diphenols and flavonoids (P <= 0.01) were significantly higher in the receptacles of 'Violet d'Hyéres' cultivar (73.0, 17.2, 15.4 and 12.2 mg 100 g-1 of fresh weight, respectively). The antioxidant activity was notably phenolic derivatives content-dependent where the higher values were observed in 'Violet d'Hyéres' cultivar. Results suggested that globe artichoke receptacles could represent a good source of health-promoting polyphenols with high antioxidant activity and this fact could encourage their consumption. Further investigations are needed to evaluate the variation of the considered compounds in other Tunisian cultivars.