Some Aspects of Nutritive and Biological Value of Carrot Cultivars with Orange, Yellow and Purple-Coloured Roots

The aim of this work was to determine antioxidant activity and some physical and chemical parameters influencing nutritive and biological value of orange, purple and yellow carrot cultivars. The two-year experiment was carried out in Warsaw Agricultural University in 2005 and 2006. Carrot was grown in the experimental field of the University. Six carrot cultivars, differed in storage roots colour and shape, were chosen for the experiment: 'Florida' F₁, 'Interceptor' F₁, 'Nebula' F₁, 'Purple Haze' F₁, 'Yellowstone', 'Mello Yello' F₁. Immediately after harvest of carrots there were determined: dry matter, total sugars content, total phenolics, total carotenoids, antioxidant activity (DPPH), fractions of dietary fibre, pectines, pH, redox potential, electrical resistance. P-value, which is a combined parameter of some physical and chemical traits, was also calculated. Correlations between some of these quality parameters were determined. Dry mater content was the highest for 'Purple Haze' in 2005, but in 2006 for 'Nebula' similar dry matter content was found. Total sugars content in carrots in 2005 was the highest in 'Purple Haze' but in 2006 'Florida' showed higher sugars content. Total phenolics content was the highest in 'Purple Haze' roots. Total carotenoids content was greatly differentiated between cultivars and varied from below 1 mg·100 g⁻¹ to above 14 mg·100 g⁻¹. For cultivars of yellow storage roots the lowest level of carotenoids were found, and the highest for orange-coloured 'Florida', 'Interceptor' and 'Purple Haze'. In all cultivars, from fractions of total fibre, the highest amount was found in the case of cellulose and pectines. The highest antioxidant activity showed purple-coloured cultivar 'Purple Haze', and the lowest activity yellow-coloured cultivars 'Yellowstone' and 'Mello Yello'. Regression analysis showed that antioxidant activity of carrot storage roots was strictly related to carotenoids content (r=0.92) and phenolics content (r=0.87).