Nutritional composition, phytochemical compounds, and antioxidant activity of onion powder are shown in Table 2. Among the flavonols analyzed, quercetin 3,4′-diglucoside and quercetin 4′-glucoside were the major flavonols in onion powder. In addition, volatile compounds were analyzed, with propionaldehyde, dipropyl disulfide, and dimethyl trisulfide as the major volatile compounds identified. It is also worth mentioning the total vitamin C content as well as the high antioxidant activity in onion powder. Onion powder composition was in agreement with data previously reported (Colina-Coca et al., 2014, Colina-Coca et al., 2013 and González-Peña et al., 2013).