Chemical characterization of Sicilian commercial cardoon honeys

Honey is known as source of natural antioxidants with application in human health. The antioxidant capacity is strongly related to the chemical composition that varies with the botanical origin, seasonal and environmental factors. Among the typical vegetables of the Mediterranean basin, the cardoon is an endemic plant with a great content of biologically active compounds, including mono- and di-caffeoylquinic acids and flavonoids, which represent the dominant fraction. During the flowering season of cardoon, a characteristic honey is produced. The aim of the present work was to evaluate the main characteristics of different Sicilian commercial honeys of cardoon. Several analyses were carried out: pH, sugars (fructose, glucose and saccharose by HPAEC-PAD), minerals (Na, K, Mg and Ca by IC), total phenols and flavonoids, phenolic composition of the typical compounds present in cardoon (by HPLC-UV/Vis) and antioxidant capacity (using DPPH, FRAP and ABTS assays). The results showed that cardoon honeys had high amounts of potassium and a good antioxidant capacity, the latter strongly correlated with phenols and flavonoids content. One of the major phenolic compounds identified is apigenin-7-O-glucuronide, which confers to honeys high antioxidant capacity, typical characteristic and traceability. The carbohydrate content was 75.74 g 100 g of honey. The ratio between fructose and glucose, equal to 1.07, shows higher tendency of cardoon honey to crystallize compared to other honeys. In conclusion, this preliminary study on Sicilian cardoon honey presented that it has a high nutraceutical value.