A Comparison of Antioxidant Capacity among Fruit, Chocolate, and Sagebrush

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Student Presentation

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Jennifer Forbey


As food molecules are broken down by the body, harmful substances called free radicals are produced. These free radicals can damage cells within the human body by stealing electrons from them. Antioxidants are substances believed to help protect cells from free radicals by giving up an electron to the free radical. The free radical is therefore reduced and does not become harmful to body cells. Different foods have different antioxidant amounts, or capacities. Because sagebrush is an abundant food source for many wildlife species and is known to contain classes of chemicals that can have antioxidant activity, we wanted to compare the antioxidant capacity of sagebrush to foods with known antioxidant activity commonly consumed by humans. Our objective was to identify whether sagebrush could provide an alternative natural source for antioxidants. We analyzed different berry types (blackberries, blueberries, huckleberries, and strawberries), four different brands of both milk and dark chocolate, and sagebrush collected from winter and summer from a single site in Idaho. We hypothesized that berry samples would have the highest antioxidant capacity overall, that the dark chocolate samples would have higher antioxidant capacity than the milk chocolate samples, and that the sagebrush samples would have the lowest antioxidant capacity overall. Samples were extracted in 70% ethanol and extracts were run through the Trolox Equivalent Antioxidant Capacity assay to determine the antioxidant capacity for each food type. We used an ANOVA to compare antioxidant capacity between food and a Tukey’s HSD test to compare all pairs. Winter sagebrush had the same antioxidant capacity as berry samples which were both twice as high as all other foods. The antioxidant capacity of dark chocolate did not differ from milk chocolate samples or spring sagebrush. However, spring sagebrush had higher activity than milk chocolate. Winter sagebrush may offer a reasonable source of antioxidants as indicated by a capacity similar to berries and a capacity higher than dark chocolate.

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