Capacidad antioxidante de diferentes variedades de cebolla: Antioxidant capacity of different onion cultivars

Abstract

The total antioxidant activity (expressed as mmol Trolox/kg of fresh onion) was determined in six cultivars of onions produced in Tenerife in order to find out differences between them. The decrease of absorbance, at 734 nm, of an ABTS (2.2´-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid) diamonium salt solution in presence of the onion sample was measured. The antioxidant activity of the onion decreases significantly from the external leaves to the internal leaves. The mean antioxidant activity of all the onion samples analyzed was 0.579 ± 0.304 mmol/kg, ranging between 0.349 ± 0.084 mmol/kg and 0.696 ± 0.371 mmol/kg. The Guayonje cultivar presented the highest mean value 0.696 ± 0.371 mmol/kg, with significant differences with respect to the San Juan de la Rambla (0.349 ± 0.084 mmol/kg) and Texas (0.398 ± 0.058 mmol/kg) cultivars, which presented the lowest antioxidant activities. Besides, it was observed that the red color of the onion was related with a higher antioxidant activity. © 2009 Taylor & Francis Group, LLC.