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ARS Home » Southeast Area » Little Rock, Arkansas » Arkansas Children's Nutrition Center » Research » Publications at this Location » Publication #183436

Title: STANDARDIZED METHODS FOR THE DETERMINATION OF ANTIOXIDANT CAPACITY AND PHENOLICS IN FOODS AND DIETARY SUPPLEMENTS

Author
item Prior, Ronald
item WU, XIANLI
item SCHAICH, KAREN

Submitted to: Journal of Agriculture and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/12/2005
Publication Date: 5/15/2005
Citation: Prior, R.L., Wu, X., Schaich, K. 2005. Standardized methods for the determination of antioxidant capacity and phenolics in foods and dietary supplements. Journal of Agricultural and Food Chemistry. 53(8):3101-3113.

Interpretive Summary: Currently the food and nutraceutical industries do not have any one standardized method that can be used for the determination of antioxidant capacity in foods and dietary supplements. Numerous methods have been used in the scientific literature and results from one method cannot be directly compared to another method. Furthermore, federal regulatory agencies do not have a basis on which to consistently evaluate health claims that relate to antioxidants. This overview provides a basis and rationale for developing standardized antioxidant capacity methods for the food, nutraceutical and dietary supplement industries. From evaluation of data presented at the First International Congress on Antioxidant Methods in 2004 and in the literature, as well as consideration of potential end uses of antioxidants, three methods were proposed for consideration for standardization: Oxygen Radical Absorbance Capacity (ORAC), the Folin-Ciocalteu method and possibly the Trolox equivalent antioxidant capacity (TEAC). The ORAC method has been extensively used by research and industry groups and utilizes a reaction mechanism which is highly relevant to human biology. The Folin-Ciocalteu method provides a measure of reducing capacity which has been used for several decades as a measure of total phenolic content of botanicals. Other assays may need to be considered in the future as we learn more about some of the other radical sources and their importance to human biology.

Technical Abstract: Methods available for the measurement of antioxidant capacity are reviewed, presenting the general chemistry underlying the assays, the types of molecules detected, and the most important advantages and shortcomings of each method. This overview provides a basis and rationale for developing standardized antioxidant capacity methods for the food, nutraceutical and dietary supplement industries. From evaluation of data presented at the First International Congress on Antioxidant Methods in 2004 and in the literature, as well as consideration of potential end uses of antioxidants, it is proposed that procedures and applications for three assays be considered for standardization: Oxygen Radical Absorbance Capacity (ORAC), the Folin-Ciocalteu method and possibly the Trolox equivalent antioxidant capacity (TEAC). ORAC represent a hydrogen atom transfer (HAT) reaction mechanism which is most relevant to human biology. The Folin-Ciocalteu method is an electron transfer (ET) based assay and gives reducing capacity which has normally been expressed as phenolic contents. The TEAC assay represents a second ET based method. Other assays may need to be considered in the future as we learn more about some of the other radical sources and their importance to human biology.