Determinação eletroanalítica e espectrofotométrica da atividade antioxidante de fermentados de jabuticaba e vinhos de diferentes procedências

• Autor(a) principal: Sá, Luísa Zaiden Carvalho Martins de
• Data de Publicação: 2013
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/3359
• topic: Vinhos; Fermentado de jabuticaba; DPPH; ABTS; Folin-Ciocalteu; Voltametria; Wine; Fermented beverage from jabuticaba; Folin- Ciocalteu; Voltammmetry; CIENCIAS DA SAUDE::FARMACIA

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.