Healthy Compounds in Globe Artichoke [Cynara cardunculus L. subsp. scolymus (L.) Hegi] Heads as Affected by Genotype and Harvest Time

The edible parts of the globe artichoke (Cynara cardunculus L. subsp. scolymus (L.) Hegi) plants are the large immature inflorescences harvested in the early stages of their development. More recently, demand has increased because of its reputation as a healthy food. The nutritional and pharmaceutical properties of artichoke heads are linked to their chemical composition, which includes high levels of antioxidant molecules, such as ascorbic acid and polyphenolic compounds (mainly clorogenic acid), inulin and minerals. Moreover, the nutraceuticals properties of the heads are linked to genotypes used and to the harvest time. With the aim to study the influence of genotype and harvest time of globe artichoke heads, four genotypes, two with early production (‘Violetto di Sicilia’ and ‘Violetto di Provenza’) and two with late production (‘Romanesco’ and ‘Blanc Hyérois’), were grown. The trial was conducted in south Sicily during 2010-2011. At commercial maturity the heads were collected and in laboratory the nutraceutical characterization was performed. In particular chlorogenic acid and ascorbic acid (HPLC-UV VIS), inulin (HPAEC – PAD), iron and potassium (spectrophotometer) were determined. On the average of genotypes, the ascorbic acid resulted 42.4 mg kg-1 FW and it was influenced by genotypes and harvest time. In the genotypes with late production the ascorbic acid amount resulted 52% higher than in the genotypes with early production. On the contrary clorogenic acid amount, which was on the average of genotypes 1324 mg kg-1 FW, resulted higher in early genotypes (1698 mg kg-1 FW) than late ones (950 mg kg-1 FW). Inulin content resulted on average 47.3 g kg-1 FW in late genotypes and 35.9 g kg-1 FW in early genotypes. The level of iron was not affected by the studied factors, on average were present 6.85 mg kg-1 FW, while the potassium content resulted higher in late genotypes (3936 mg kg-1 FW) than early genotypes (3679 mg kg-1 FW).