Determinação eletroanalítica e espectrofotométrica da atividade antioxidante de fermentados de jabuticaba e vinhos de diferentes procedências
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2013-03-28
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Universidade Federal de Goiás
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The consumption of wine has been associated with health promoting properties due
to the high content of phenolic compounds, what makes wines an important dietary
source of antioxidants. Jabuticaba fermented beverages, as much as wine, have a
high content of phenolic compounds. In this study, traditional spectrophotometric
methods (ABTS, DPPH, Folin-Ciocalteu) as well as novel methods (Cyclic
Voltammetry - CV, Differential Pulse Voltammetry - DPV and Square Wave
Voltammetry - SWV) have been used to evaluate the antioxidant activity of wines of
different origin a jabuticaba fermented beverages and a jabuticaba brandy.
Furthermore, an Electroanalytical Index (EI) has been proposed in order to allow the
comparison of the antioxidant activity measured by electroanalytical methods. For the
fermented beverages of jabuticaba, it has been demonstrated in the five methods
that all three varieties, red, white and rose, have high antioxidant potential, very
similar to a red dry wine, while the brandy has not shown any peaks in voltammetric
analysis. In the analyzes by DPPH, red wines have shown about five times as much
the antioxidant capacity of white wines, while for the EI it is twice as much when
compared to white wines. Rose, white and fortified wines have shown lower EI than
the red wine. It has been determined a Pearson correlation of -0.91097 between the
DPPH method and the EI. The proposed EI allows comparison of the amount of
electroactive compounds determined in the various wine samples analyzed.
Considering the electroactive nature of the antioxidant compounds, electroanalytical
methods have been demonstrated suitable for studying such compounds. Its main
disadvantage was the high adsorption process due to the phenolic oxidation on the
electrode´s surface, creating an isolating film on it. This process has been overcome
by the use of carbon paste electrode.
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SÁ, Luísa Zaiden Carvalho Martins de. Determinação eletroanalítica e espectrofotométrica da atividade antioxidante de fermentados de jabuticaba e vinhos de diferentes procedências. 2013. 98 f. Dissertação (Mestrado em Ciências Farmacêuticas) - Universidade Federal de Goiás, Goiânia, 2013.