Method for the determination of the reducing capacity of products or mixtures containing anti-oxidizing substances

Method for the determination of the Reducing Capacity of products or mixtures containing anti-oxidizing substances, in particular food, beverages, cosmetics and similar products, including liquid chromatographic separation HPLC of one or more reducing substances from a sample of the above mentioned food, beverages, cosmetics, herbs and similar products and the following on-line determination of such substances by means of a coulometric detector, comprising the following steps: a) Extracting a hydrophilic substances containing fraction and a lipophilic substances containing fraction from a sample of the product to be analyzed; b) Subjecting each of said fractions to liquid chromatographic separation; c) Determining said hydrophilic and/or lipophilic reducing substances by means of a coulometric detector equipped with an electrode set to a potential between 0 and 1000 mV. The information relating to the amount of each of said hydrophilic and lipophilic reducing substances is processed to obtain the hydrophilic reducing capacity (HRC), the lipophilic reducing capacity (LRC) and the total reducing capacity (TRC), expressed as Trolog concentration or by means of degrees of a corresponding centesimal scale.