Resumo Este estudo objetivou caracterizar compostos bioativos e atividade antirradicalar em farinhas de bagaços de uvas das cultivares Cabernet Sauvignon, Merlot, Sauvignon Blanc e Sangiovese (Vitis vinifera), desidratados em estufa de circulação de ar a 45 °C ou liofilizador a vácuo. Foram analisados compostos fenólicos totais e individuais, antocianinas monoméricas e atividade antirradicalar pelos métodos ABTS e HOCl. A perda total de antocianinas monoméricas foi maior para as cultivares Cabernet Sauvignon e Sangiovese, pelo método de desidratação em estufa. Todas as cultivares liofilizadas preservaram índices estatisticamente superiores de compostos fenólicos totais, com superioridade para a cultivar Sauvignon Blanc. Na análise individual destes compostos, as amostras liofilizadas tiveram maiores teores médios de todos os flavonoides (epicatequina, catequina, quercetina, ácido vanílico, rutina), enquanto que os ácidos gálico, cafeico e ferrúlico, aparentemente, não foram influenciados pelo método de secagem. Todas as amostras desidratadas em estufa tiveram menor capacidade de inibição dos radicais livres em relação às amostras liofilizadas, por ambos os métodos de IC50. O método ABTS apresentou os melhores resultados para as amostras liofilizadas, ou seja, quantidades menores das farinhas foram capazes de inibir em pelo menos 50% a atividade dos radicais livres ABTS e HOCl, com destaque para a cultivar Merlot.

Abstract This study aimed to characterize the bioactive compounds and antiradical activity in grape pomace flours from the cultivars Cabernet Sauvignon, Merlot, Sauvignon Blanc and Sangiovese (Vitis vinifera), dehydrated either in an air circulation oven at 45 °C or a vacuum freeze dryer. The total and individual phenolic compounds, monomeric anthocyanins and antiradical activity were analysed by the ABTS and HOCl methods. The total loss of monomeric anthocyanins was higher for the cultivars Cabernet Sauvignon and Sangiovese dehydrated in the air circulation oven. All the freeze dried cultivars preserved a statistically higher index for the total phenolic compounds, the highest being the cultivar Sauvignon Blanc. In the individual analysis of these compounds the freeze dried samples showed higher average levels of all the flavonoids (epicatechin, catechin, quercetin, vanillic acid, rutin), whereas gallic, caffeic and ferulic acids were apparently not influenced by the drying method. All the samples dehydrated in the oven showed less free radical inhibition capacity than the freeze dried samples as determined by both IC50 methods. The ABTS method presented the best results for the freeze dried samples, that is, smaller amounts of the flours were able to inhibit at least 50% of the ABTS and HOCl free radical activities, with emphasis on the Merlot cultivar.

Infusions of yerba mate obtained at different stages of industrialization were evaluated to determine the bioavailable fraction of Al. Adsorptive Cathodic Stripping Voltammetry using DASA (complexing agent) was applied to determine the labile fraction of Al at pH 5.0 and pH 8.0 for the total fraction of dissolved Al. The results indicate that on average 60% of Al is complexed with organic compounds, minimizing their bioavailability; however, the labile fraction exceeds by up to 4 times the maximum weekly intake recommended by the World Health Organization.

Propolis is mostly used as hydroalcoholic extract. Recently there has been a growing number of patents dealing with new solvents for preparing propolis extracts. This study aimed to prepare edible oil propolis extracts and compare their chemical composition and biological activity with ethanolic propolis extracts. ESI-MS and spectrophotometric methods were used for qualitative and quantitative analyses, respectively. Antibacterial activity was evaluated by diffusion in agar. Cytotoxicity was tested by MTT assay using tumor cell lines. The oil is able to extract bioactive compounds from propolis. Further studies are needed to improve extraction efficiency and to characterize the active components.