3.2. Total polyphenolic compounds (TPC)
Drying methods caused a significant decrease in total polyphenols
content as non-processed berries contained 2.28 ± 0.07 g
GAE 100 g1 DM, while dried fruits comprised from 0.71 ± 0.01
(69% decrease of initial TPC) to 1.26 ± 0.02 g (45% decrease of initial
TPC) GAE 100 g1 DM (Fig. 3a). Among the single-stage drying
methods, higher content of TPC (1.26 ± 0.02 g GAE 100 g1 DM)
was noticed after drying using HACD at 90 C, while MWVD
resulted in lower content of TPC (0.87 ± 0.02 g GAE 100 g1 DM)
(Fig. 3a). HACD with higher air temperature and shorter drying
times resulted in a higher content of compounds able to react with
a Folin-Ciocalteu reagent as also reducing substances (carbohydrates)
and nitrogen-containing compounds including proteins
formed during temperature-dependent processing.