Comparative analysis of nutritional and chemical profiles of Tiggiano and Polignano carrots

The Polignano and Tiggiano carrots are traditional multicoloured landraces from the Apulia region in Southern Italy, characterised by multicoloured taproots and distinct organoleptic properties. This study offers a comprehensive comparative analysis of their volatile and non-volatile secondary metabolite profiles, compared to a commercial orange carrot cultivar. Quantitative analysis revealed that the Polignano carrot contains significantly higher total polyphenols (6.25 mg GAE/g DW) than both Tiggiano (2.95 mg GAE/g DW) and orange carrots (0.82 mg GAE/g DW). Both Apulian landraces, based on their coloration, contain anthocyanins which are absent in orange carrots. Lutein content was also notably greater in the multicoloured landraces (Polignano: 61.21 μg/g DW; Tiggiano: 48.00 μg/g DW) compared to the orange cultivar (7.65 μg/g DW), whereas β-carotene was highest in the commercial orange variety (216.04 μg/g DW). Antioxidant capacity mirrored these trends, with hydrophilic TEAC values of 4.19, 2.54, and 0.49 mmol TE/100g DW for Polignano, Tiggiano, and orange carrots, respectively. The volatile analysis, performed for the first time on these landraces, identified 42 compounds, with sesquiterpenes and monoterpenes as the predominant classes. PCA and hierarchical clustering revealed distinct aromatic fingerprints for each variety, with sabinene, γ-terpinene, and caryophyllene significantly enriched in the landraces. Correlation analyses highlighted key biosynthetic interdependencies between volatile terpenoids and non-volatile antioxidants, underscoring metabolic trade-offs. These results confirm the high nutritional value and unique sensory profiles of Apulian landraces, supporting their valorisation, conservation, and potential for Geographical Indication certification.