ORAC: Oxygen Radical Absorbance Capacity
Oxygen Radical Absorbance Capacity (ORAC) is a method of measuring antioxidant capacities of different foods. It was developed by the scientists at the National Institute on Aging in the National Institutes of Health (NIH). A wide variety of foods have been tested using this methodology, with certain spices, berries and legumes rated very highly. Correlation between the high antioxidant capacity of fruits and vegetables, and the positive impact of diets high in fruits and vegetables, is believed to play an important role in the free radical theory of aging.
The original idea of the ORAC is based on the oxidative degradation of the fluorescent molecule after being mixed with free radical generators. Antioxidants are able to protect the fluorescent molecule from the oxidative degeneration. One benefit of using the ORAC method to evaluate substance's antioxidant capacity is that it takes into account samples with and without lag phases of their antioxidant capacities. This is especially beneficial when measuring foods and supplements that contain complex ingredients with various slow and fast acting antioxidants, as well as ingredients with combined effects that cannot be pre-calculated.