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Advisor(s)
Abstract(s)
The antioxidant activity and phenolic composition of brewer's spent grain (BSG) extracts obtained by
microwave-assisted extraction from twomalt types (light and darkmalts) were investigated. The total phenolic
content (TPC) and antioxidant activity among the light BSG extracts (pilsen, melano, melano 80 and carared)were
significantly different (p b 0.05) compared to dark extracts (chocolate and black types), with the pilsen BSG
showing higher TPC (20 ± 1 mgGAE/g dry BSG). In addition, the antioxidant activity assessed by 2,2-diphenyl-
1-picrylhydrazyl, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) and deoxyribose assays decreased as
a result of increasing kilning temperatures in the following order: pilsen N melano N melano 80 N carared N
chocolate N black. HPLC-DAD/ESI-MS/MS analysis indicated the presence of phenolic acids, such as ferulic,
p-coumaric and syringic acids, as well as several isomeric ferulate dehydrodimers and one dehydrotrimer. Chocolate
and black extracts, obtained frommalts submitted to the highest kilning temperatures, showed the lowest levels of
ferulic and p-coumaric acids. These results suggested that BSG extracts from pilsen malt might be used as an
inexpensive and good natural source of antioxidants with potential interest for the food, pharmaceutical and/or
cosmetic industries after purification.
Description
Keywords
Brewer's spent grain Microwave-assisted extraction Polyphenols Antioxidant activity Kilning temperature HPLC-DAD/ESI-MS/MS analysis