Application of Briggs-rauscher Reaction for Measurement of Antioxidant Capacity of Croatian Wines

Briggs-Rauscher (BR) reaction is one of the most commonly studied oscillation reactions which has been applied for measurement of antioxidant activity of water-soluble substances. By addition of free radicals (from fruits or vegetables), there is an immediate quenching of oscillations. The reaction is followed potentiometrically and the inhibition time (IT), or time of no oscillations, is proportional to concentration of antioxidant. pH of BR reaction is about 2, what is similar to that of the fluids of the main digestive process (human stomach), giving in vitro information’s on antioxidant activity at “real digestion conditions” and can help in assessment of nutrition for maintenance of health and prevention of diseases. Antioxidant activities of different concentrations of native Croatian red and white wines are analysed by inhibition of BR reaction and determination of total phenols using galic acid as the calibration standard. By use of mathematical models, relative antioxidant activities of antioxidants and amounts of total phenols are estimated. Second order polynomial calibration curve is estimated in the range of 150-2500 galic acid equivalent (GAE mg l), with standard error of 84 GAE mg l .