Root pigmentation determines phytochemical, mineral, antioxidant and organoleptic attributes of Tunisian southern coastal carrot (Daucus carota subsp. sativus) landraces

Abstract

Carrot (Daucus carota subsp. sativus) is a widely grown crop in temperate regions of the world, consumed by humans as an important source of nutrition. This study focused on five local varieties of carrots from irrigated regions of southern Tunisia (Sidi Sallem, Sagui, Arram, ElGrine and Boughrara) with different root pigmentation. The carrots were evaluated for their morphological, physicochemical, biochemical, and organoleptic characteristics. Morphological characterization showed significant differences (p<0.01) in length, weight, and diameter of the root part and aerial part among the five landraces. The pH, titratable acidity, and Brix values were also different for each landrace, ranging from 6.18 (Sagui) to 6.27 (Arram), 0.016 (Boughrara) to 0.045 mg.g − 1 citric acid (Arram), and 5.60 (Arram) to 7.80% (Sidi Sallem), respectively. The study also identified 10 phenolic acids through LC-ESI/MS analysis, with quinic acid, protocachuic acid, and chlorogenic acid being the most abundant compounds. The HPLC method was used to analyze the sugar and β-carotene contents of the landraces. Results showed that the Sidi Sallem landrace had the highest fructose (625 mg.kg−1 DM), glucose (1000 mg.kg−1 DM), and β-carotene (2551.808 mg. kg−1 DM) contents. Sagui had the highest levels of α-tocopherol (vitamin E) (236 μg. L − 1) and vitamin K2 (6.5 μg. L − 1). Sensory analysis of the juices and pureed salads prepared from the five carrot landraces confirmed the findings of the morphological and nutritional evaluations. This research suggests that a participatory breeding program should be considered to preserve genetic resources and improve them in terms of nutritional quality criteria. The work highlights the nutritional value of carrot as a source of natural antioxidant compounds, which may be beneficial in the food and pharmaceutical industries.