Culinary Method Affects the Antioxidant Activity of Collard Greens (Brassica oleracea)

The antioxidant activity of collard greens was determined after exposed to eight different thermal treatments: 1) untreated raw group, 2) short simmer 3short simmer water 4) short simmer + saute’, 5) saute’ 6) long simmer 7) long simmer water 8) long simmer + saute’. After treatment, total phenolic content (TPC) expressed in gallic acid equivalents/sample concentration (GAE/conc.), 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferrous ion chelating (FIC) antioxidant assays were determined. The sauté treated group showed the highest TPC (8.2858 GAE/conc.) followed by the raw group (8.0361) and the short simmer + sauté group (7.6227). The raw group showed the highest DPPH activity (7.7952% inhibition/conc.) followed by the sauté group (7.5877) and the short simmer + sauté group (7.4753). In both of these assays the addition of a sauté treatment to either short or long simmered treatment increased the antioxidant activity of samples compared to just the short or long simmer treatment alone. Additionally both TPC and DPPH assays showed greater antioxidant activity in the cooking water reserved from a long simmer treatment compared to the reserved cooking water of a short simmer treatment suggesting significant (p<0.05) leeching of antioxidants from collard greens into the water related to the duration of aquathermal treatment. Similar trends were not found in the results of the FIC chelating assay where both long and short simmer treatment groups showed the highest chelating abilities and the reserved cooking water from both treatments showed the lowest chelating abilities. This suggests that chelators contained in collard greens were not relatively water soluble and therefore not negatively affected byaquathermal treatments.