Portuguese Foundation for Science and Technology (FCT) and to
Mountain Research Center. J.C.M. Barreira thanks to FCT, Human Potential Operational Programme-
National Strategic Reference Framework (POPH-QREN) and FSE for his grant (SFRH/BPD/72802/2010).
Several herbal beverages claim medicinal benefits due to their antioxidant
properties. However, operational factors such as the extracted herbal component,
preparation method or concentration levels, might influence their biological activity. To
assess this effect, the antioxidant activity of beverages prepared with Camellia sinensis,
Aspalathus linearis or Cochlospermum angolensis, used solely or mixed with different
fruit, plant or algae extracts, was studied using different formulations (bags, leaves, roots,
granulates, powders, liquids) and different preparation methods (infusion, solubilisation or
promptly used). The DF50 (dilution factor responsible for 50% of antioxidant activity)
values were calculated to compare their antioxidant activity. A linear discriminant analysis
was used to categorize the assayed samples according to their antioxidant activity and
bioactive molecules profiles. The results indicated that antioxidant activity and antioxidant
compounds are significantly affected by formulation and preparation method, but overall
the labelled antioxidant benefits were validated. Green tea showed the highest activity, but
with different behaviour within each used formulation. The high DF50 values calculated for
some products might be used to adjust the dietary dose or formulation, preventing also
putative pro-oxidant effects. Hence, the obtained results might be useful to define the
formulation of these highly consumed herbal beverages, enhancing their health effects.
