Leaf phenolic fingerprints of chicory cultivars (Cichorium intybus L.) hydroponically forced in different nutrient solutions

• Under different nutrients, 44 phenolics were extracted from five chicons cultivars.
• The phenolics varied widely among analysed hydroponically forced chicons.
• Twelve phenolics were specifically identified using HPLC-DAD metabolomics.
• Chicons phenolics profiles are influenced by cultivar and forcing nutrient solution.
• The remaining grouped unknown phenolic compounds are the predominant phenolics.

The phenolic profiles of leaves of hydroponically forced chicons from five chicory (Cichorium intybus L.) cultivars were determined: ‘Treviso’, ‘Verona’, ‘Anivip’, ‘Castelfranco’ and ‘Monivip’. The chicory roots were forced in the dark in three fertiliser solutions enriched in nitrogen (N), phosphorus (P) and/or potassium (K) (i.e., N/P/K, N/P, N alone), each applied at 10, 20 and 30 g/L. Phenolics were extracted from the chicon leaves and quantitatively evaluated in an HPLC-DAD–based study. ‘Castelfranco’ showed the highest total phenolics (19.79 mg/g dry weight [DW]), and ‘Monivip’ the lowest (15.31 mg/g DW). Across the nutrient solutions, the highest total phenolics was with N/K-1% (19.87 mg/g DW), followed by N/P/K-1% (18.91 mg/g DW), and the lowest with N-1% (14.22 mg/g DW). Determining these phenolics profiles of forced chicons not only contributes to the knowledge of their nutritional value, but also provides a solid foundation for further understanding of their total phenolics formation during hydroponic forcing.