Food and ascorbic scavengers of hydrogen peroxide : a reaction calorimetry investigation

Common spectrometric methods to determine hydrogen peroxide scavenging activity require time-consuming extraction protocols and become poorly reliable because of the sample turbidity or the presence of UV-absorbing compounds. The present work suggests the use of reaction calorimetry to determine the antioxidant capacity of fruit juices, fruit puree, tea, coffee and alcoholic beverages, like wines. This experimental approach that does not imply the above drawbacks and does not require any extraction protocol allows the direct monitoring of the reaction between food beverages and H2O2. The overall exothermic effect reflects the extent of the scavenging activity of the samples versus hydrogen peroxide. The reliability of the approach is assessed through the study of the reaction between hydrogen peroxide and ascorbic acid at different concentration and pH at room temperature.