Determination of antioxidant capacity in some fruit concentrates and powders by different methods

There is a great demand on consumption of natural and healthy foods, which includes also fresh fruits and food products made by different technological processes. In our experiment, fruit concentrates and powders of elderberry (Sambucus nigra L.) and blackcurrant (Ribes nigrum L.) were studied. For evaluating their health protective effect, the antioxidant/ reducing properties of both fruits were obtained. The total phenolic content (TPC) and the antioxidant capacity determined by the FRAP, TEAC, and DPPH methods were analysed. Results are expressed on a dry matter basis for better comparison. TPC and antioxidant activity detected by different methods were higher in elderberry (Sambucus nigra L.) for both concentrates and powders than in blackcurrant (Ribes nigrum L.). Dry powders made from fruit concentrates showed in almost all cases a lower antioxidant activity than the concentrates. The results clearly show that it is recommended to characterize the antioxidant properties in as many ways as possible in order to evaluate the beneficial effects of fruits and their processed goods on the human organism