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Advisor(s)
Abstract(s)
This paper reports a novel application of
microwave-assisted extraction (MAE) of polyphenols from
brewer’s spent grains (BSG). A 24 orthogonal composite
design was used to obtain the optimal conditions of MAE.
The influence of the MAE operational parameters (extraction
time, temperature, solvent volume and stirring speed)
on the extraction yield of ferulic acid was investigated
through response surface methodology. The results showed
that the optimal conditions were 15 min extraction time,
100 °C extraction temperature, 20 mL of solvent, and maximum
stirring speed. Under these conditions, the yield of
ferulic acid was 1.31±0.04% (w/w), which was fivefold
higher than that obtained with conventional solid–liquid
extraction techniques. The developed new extraction method
considerably reduces extraction time, energy and solvent
consumption, while generating fewer wastes. HPLC-DADMS
analysis indicated that other hydroxycinnamic acids and
several ferulic acid dehydrodimers, as well as one dehydrotrimer
were also present, confirming that BSG is a valuable
source of antioxidant compounds.
Description
Keywords
Brewer’s spent grain Polyphenols Ferulic acid Microwave-assisted extraction HPLC-DAD-MS analysis