Meeting Abstract

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Screening methods for evaluating antioxidant levels of sorghum and their products. J.M. AWIKA (1), L.W. Rooney (1), X.L. Wu (2), R.L. Prior (2), and L. Cisneros-Zevallos (1). (1) Texas A&M University, College Station, TX 77840; (2) Arkansas Children's Nutrition Center, Little Rock, AK.

A rapid, reliable and inexpensive method of screening food and food products for antioxidant activity is necessary.Three methods to measure antioxidant potential of sorghum and their products were compared to a standardized oxygen radical absorbance capacity (ORAC) method. The methods were the 2,2´-azinobis (3-ethyl-benzothiaziline-6-sulfonic acid) (ABTS), the 2,2-diphenyl-1-picrylhydrazyl (DPPH), and total phenol (Folin-Ciocalteu) assays. The antioxidant activities were compared to those of common fruits and vegetables. The ABTS, DPPH, and phenol values correlated highly with ORAC (R(^2) over 0.96, n = 18). The ABTS method was found most suitable for sorghums; it had a cost advantage over ORAC and was more consistent across samples than DPPH and total phenol methods. Specialty sorghum brans had antioxidant activity (ORAC method) ranging from 700 to 3,100 µmol TE per g). Common fruits and vegetables have ORAC activities ranging from less than 80 to about 900 µmol TE per g, DM basis. Specialty sorghums have high antioxidant activity relative to fruits and vegetables and have good potential as a source of nutraceuticals in foods. The ABTS method is suitable for screening sorghums and their products for antioxidant potential.