Dr. N. Joy Dubost, who recently earned her doctorate in food science at Penn State, measured the activity of two antioxidants, polyphenols and ergothioneine, present in mushrooms, using the ORAC assay and HPLC instrumentation, as part of her dissertation research. She found that portabella mushrooms had an ORAC value of 9.7 micromoles of trolox equivalents per gram and criminis had an ORAC value of 9.5. Data available from other researchers shows carrots and green beans have an ORAC value of 5; red pepper 10; and broccoli 12.
The ORAC assay, the most well known test of antioxidant capacity, focuses on the peroxyl radical, the most predominate in the human body. Free radicals, such as the peroxyl radical, are thought to play a role in the aging process and in many diseases, including cancer, Alzheimer's and atherosclerosis. Epidemiological studies have shown that those who eat the most fruits and vegetables rich in antioxidants have lower incidence of these diseases.
Dubost detailed her results in a paper, Quantification of Polyphenols and Ergothioneine in Cultivated Mushrooms and Correlation to Total Antioxidant Capacity Using the ORAC and HORAC Assays, presented Monday, June 26, at the Institute of Food Technologists meeting in Orlando, Fl. Her co-author is her dissertation adviser, Dr. Robert Beelman, professor of food science.
Dubost explains that assays are a first step toward determining how effective a food is in providing protection against oxidative damage. Anti-oxidants inhibit increased rates of oxidation, which can damage proteins, lipids carbohydrates and DNA.
She adds, "The ORAC assay does not tell what happens in the human body but this assay is currently under investigation as to how it can predict physiological activity."