a b s t r a c t
The goal of this study was to determine the best conditions to obtain the highest total polyphenol content from mate
bark
aqueous
extract
and
investigate
the
phenolic
composition
and
antioxidant
activity
of
the
concentrate
obtained
during nanofiltration. The Response Surface was employed to determine the optimum condition for extraction of
polyphenolics from mate bark aqueous extract. The extract obtained using the best conditions (a temperature of
85
±
5 ◦
C and with extraction time of 1.5 min) contained approximately 1.6 mg/mL of chlorogenic acid equivalent,
and was subjected to nanofiltration. The total polyphenol content values in the permeate and in the concentrate
collected
at
different
volume
reduction
factors
(VRF
of
1.5–6) were different from those detected in the optimized
extract (unfiltered). The concentration of phenolic compounds and antioxidant activity increased when VRF was
increased. The major compounds detected in optimized mate bark extract and its concentrates (VRF 4 and 6) were
chlorogenic acid and epigallocatechin gallate, which can be related to the high antioxidant activity of mate bark
aqueous extract.
© 2011 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
Keywords: Ilex paraguariensis; Mate bark aqueous extract; Phenolic compounds; Concentrate; Antioxidant activity;
Nanofiltration