Total Phenolics and Antioxidant Capacity of Vegetables Grown in the Southwestern Andes Region of South America

Abstract

The antioxidant richness of 69 species and/or varieties of vegetables grown in the southwestern Andes region of South America, including some endemic varieties, was evaluated in terms of their total phenolics (TP) and oxygen radical absorbance capacity (ORAC). Parsley, basil and coriander rank notably higher among those species that are commonly consumed in their raw state, exhibiting TP and ORAC values that are comparable to those reported earlier by us for various antioxidant-rich indigenous berries. For a given species, major differences were also seen among its varieties; in the case of tomatoes and lettuce, the maximal-to-minimal differences in ORAC values reached 16- and 28-fold, respectively. For those vegetables that are not consumed raw, the boil-cooking process affected differentially the antioxidant richness; for instance, while in the case of asparagus, chard, and lima beans boil-cooking induced major drops in ORAC (40-60%), in the case of artichoke bottoms a marked increase (35%) in ORAC was seen. Within the frame of building rankings of antioxidant richness, in the present work substantial data are also presented to highlight the concept that when assessing the antioxidant supply potential of any vegetable, besides quantifying its antioxidant richness per 100 g, considering its actual portion of consumption is also fundamental. On such basis, among the 29 vegetables analyzed in their cooked state, the endemic and regionally-grown Michune, Cabrita, and purple varieties of potatoes emerge as the top 3 antioxidant-rich plant foods.