Influence of cultivation sites on sterol, nitrate, total phenolic contents and antioxidant activity in endive and stem chicory edible products

Abstract

Chicories produce a wide range of vegetables with important nutritional value. We determined the variation of sterol, total polyphenol, nitrate contents and antioxidant capacity (SC, TPC, NC, AC) in endive leaves and stem-chicory novel vegetables, cultivated in two Italian regions. Within a given area, the SC was similar in smooth- and curly leafed endives (106.3–176.0 mg/kg FW); sitosterol and stigmasterol were major fractions (45–56 versus 38–43%). The stem SC was independent of landrace (101.5–118.6 mg/kg FW); sitosterol prevailed on stigmasterol and fucosterol (73–76 versus 12–14% versus 8–9%); the latter reached 15.7 mg/kg FW, conferring value as potential antidiabetes food. The planting site affected the AC and TPC of endives (893.1–1571.4 μmTE/100 g FW, 30.8–76.1 GAE100/g FW) and chicory stems (729.8–1152.5 μmTE/100 g FW; 56.2–124.4 GAE100/g FW), while the NC was recurrently below dangerous thresholds. PCA showed that environment was the major cause of variation, though it modestly affected these parameters.

Keywords:

• Phytosterols
• antioxidant capacity
• total phenolic content
• nitrate content
• endive
• stem-chicory
• novel vegetables

Acknowledgements

We thank T. Biancari (EZ) for agronomical support, A. Tozzi and L. Lilla (IMC-CNR) for technical assistance in samples preparation for GC-MS analysis, G. Favuzzi (Azienda Sempreverde, BA, IT) for providing seed lots of chicory landraces. We also thank the native English speaker Enza Sirugo for language editing.

Disclosure statement

The authors report no conflicts of interest and are responsible for the content of this article.