Nutritional characteristics and antiradical activity of turmeric (Curcuma longa L.), beetroot (Beta vulgaris L.), and carrot (Daucus carota L.) grown in Bangladesh

Curcuma longa L. (turmeric), Beta vulgaris L. (beetroot), and Daucus carota L. (carrot) grown in Bangladesh were analyzed for nutritional and phytochemical contents to reveal their comparative nutritional compositions and antiradical properties. Ash, protein, and carbohydrate content were significantly preeminent in beetroot as compared to others. Whereas fat content was found to be high in turmeric, carrots contained a great percentage of crude fiber. Beetroot was shown to have much greater potassium, calcium, and iron levels than others. Regarding amino acids, glutamic acid was found to be greater in beetroot and carrot whereas turmeric had significantly high aspartic acid content. Leucine had the highest concentration among essential amino acids in these three samples. Total antioxidant activity, total flavonoids, and phenolic contents in the methanolic extract of turmeric were found to be substantially higher than in beetroot and carrot. Furthermore, the extract of turmeric (IC(50) value: 13.46 μg/mL) scavenged 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) free radicals considerably to a greater extent than beetroot (IC(50) value: 380.61 μg/mL) and carrot (IC(50) value: 1252.85 μg/mL). A positive correlation was found between the phytochemical contents and antiradical activity. The information from this study will help to find the potential ingredients from these plants for functional food.