Antioxidant and Antioxidant capacity of raw and processed Nigerian Beetroot (Beta vulgaris)

Abstract

Raw and processed Beetroot (Beta vulgaris) were assessed for the natural antioxidants; Total phenol, flavonoids, vitamin C using Folin-Ciocalteau, potassium acetate and dinitophenyl hydrazine. The antioxidant radical scavenging abilities were evaluated using 2,2’-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) [ABTS] and ferric reducing antioxidant property [FRAP] respectively. Raw beetroots and the beetroot juice contained the highest amount of total phenol (98.08. ± 8.16mg/g and 98.08. ± 5.77mg/GAE/g) respectively. Oven dried beetroot have the lowest value for total phenol (94.23 ± 2.72mg/GAE/g. The heat treated beetroot had the highest flavonoids of 96.67±10.10mgGE/g. Flavonoids were lowest for the raw beetroot (63.34±4.72mg/QE/g). Oven dried and Beetroot juice have a total flavonoid value of 83.34 ± 4.471mg/GE/g and 83.34 ± 3.34mg/GE/g respectively. Vitamin C content was highest in Beetroot juice (44.34±2.84mgAAE/g) and lowest in heat treated beetroot (30.18±0.61mgAAE/g). Heat treated Beetroot have the highest value for ABTS scavenging ability. FRAP value (33.33 ±0.00) was highest in oven dried beetroot. Raw Beetroot and its juice possess significant antioxidant and radical scavenging abilities which correlated positively with the natural antioxidants. Heat treatment however, increased the flavonoids present in the beetroot samples with a corresponding increase in the ABTS and FRAP scavenging abilities (19.85± 4.15 and 33.33 ±0.00) respectively. Beetroot in its natural and processed form is a rich source of antioxidants and free antioxidants scavenging abilities

Keywords: Antioxidants, Antioxidant capacity, free radicals, Beetroots