Influence of Agro-Ecological Areas on the Antioxidant Capacity of Onion Varieties Grown in Burkina Faso

Abstract

Colored onion bulb is an important source of antioxidants. Some ecological factors can significantly influence the content and quality of these substances. The aim of the present study is to determine the antioxidant and total polyphenol content of fresh bulbs of five (05) varieties of onion (Galmi Violet, Damani Violet, Prema, Safari and a Local variety-LV) grown in Burkina Faso, and to evaluate also the influence of agro-ecological parameters on the antioxidant content of the most cultivated variety (Galmi violet) of them. Samples of onion bulb for analysis were collected in the six agro-ecological areas of Burkina Faso under the same cultivation conditions. Antioxidant activities were evaluated using the method of Ferric Reducing Antioxidant Power. The evaluation of the total polyphenol contents was carried out using the Folin-Ciocalteu method. The results showed that antioxidant activities for the 5 varieties tested vary between 0.125 ± 0.001 and 0.149 ± 0.004 mg TE / g, and total polyphenol contents from 0.172 ± 0.011 to 0.272 ± 0.003 mg EAG/g. Results on the assessment of the effect of ecology on the antioxidant content of Galmi violet variety revealed significant variations in antioxidant content from 0.144 ± 0.002 to 0.155 ± 0.001 mg TE / g, and total polyphenols from 0.208 ± 0.014 to 0.292 ± 0.012 mg EAG / g depending on the ecological cultivation area.

Influences of Storage Conditions, Cultivation and Culinary Practices, On the Antioxidant Capacity of Red Bulbs of Some Onion Varieties Grown in Burkina Faso

“…The same source states that, soils rich in humus with high biological activity can positively modify the concentration and the combination of antioxidants in harvested fruits and vegetables, compared to soils that are regularly fumigated and extensively chemical fertilized, and which have a generally lower bioactivity [41]. It could be argued that the ability of organic farming practices to increase the antioxidant content of fruits and vegetables would come from the use of organic fertilizers and pesticides, which are very rich in organic and probably other agro-ecological parameters could explain the increase of antioxidant content in organic farming according to many authors, Dakéné, et al [42]; Sereme, et al [43]; Dabire, et al [44].…”