Author
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Wang, Shiow |
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JIAO, HONGJUN - GUANGI UNIV, P.R. CHINA |
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Submitted to: Proceeding Intl Symposium Postharvest Science Technology Horticulture Crops
Publication Type: Proceedings Publication Acceptance Date: 7/14/2000 Publication Date: N/A Citation: N/A Interpretive Summary: Technical Abstract: Reactive oxygen species are generated as by-products of normal metabolism. Increased levels of these active oxygen species or free radicals create oxidative stress, which leads to a variety of biochemical and physiological lesions often resulting in impairment of metabolism, and eventually cell death. Fruits and vegetables contain high levels of antioxidant compounds, which provide protection against harmful free radicals and have been associated with lower incidence and mortality rates of cancer and heart disease in addition to a number of other health benefits. Antioxidant capacity varies considerably among different types of fruits and vegetables. A number of assays have been introduced for measuring total antioxidant activity of foods, plant material, serum, plasma, biological fluids and pure compounds. Each method relates to the generation of a different radical, acting through a variety of mechanisms and measurement of a range of end points at a fixed time point or over a range. Two approaches have been taken: 1) inhibition assays which measure the degree of scavenging by hydrogen- or electron - donation of a pre-formed free radical as a marker of antioxidant activity, and 2) assays involving the presence of an antioxidant system during the generation of a radical. This paper will discuss and compare the principles and applications of five of the most commonly used methods (ABTS/H2O2/HRP end-point; ABTS/H2O2/HRP lag; ABTS/H2O2/ Myoglobin; ORAC and TRAP) for the measurement of total antioxidant activity in plant materials. |
