The aim of this work was to study the extraction of phenolic
compounds from chestnut bur and shell, both waste products of
chestnut processing in the food industry. Two extraction techniques
were compared—maceration with solvents and microwaveassisted
extraction. The influence of the solvent used (water,
50% MeOH or 50% EtOH) and temperature (25-50-75 C) on
extraction yield and extract total phenols content and FRAP,
DPPH, and ABTS antioxidant activities was studied. In the
conventional extraction, the yield was significantly higher for
the bur (8.54–19.58%) than for the shell (2.91–13.27%); however,
the shell extracts showed substantially greater properties. The
best extract properties were achieved at 75 C using 50% MeOH
for the bur and water for the shell and phenolic compounds
with demonstrated antioxidant properties, as gallic acid esters
of glucose and ellagic acid, were identified in these extracts by
RP-HPLC-ESI-TOF. In addition, the aqueous extracts showed
ability to inhibit the growth of gram positive and negative bacteria
but not fungi. The kinetic of the extraction process was well
fitted by the Peleg’s model. The non-conventional microwaveassisted
extraction slightly improved the chestnut bur extraction
by reducing the extraction time.
This work was funded by Ministerio de Ciencia e
Innovación, FEDER Funds and Plan E Fundy
(CTQ2009-07539) and Fundação para a Ciência e Tecnologia
(Portugal) PEst-OE/AGR/UI0690/2011. The authors
are also grateful to ‘‘Fundación Segundo Gil Dávila’’ for
a research grant awarded to Adela Fernández Agulló
