Abstract In the elaboration of young red wine, it is necessary to obtain a clear product with stable color. The clarity and stability can be obtained using fining agents. The objective of this study was to evaluate the combined effect of fining with pea protein isolate (PPI), bentonite, and polyvinylpyrrolidone (PVPP) on a red wine, using the experimental design of mixtures. Merlot wine was used to evaluate the changes on monomeric flavan-3-ol, turbidity and anthocyanin levels promoted by the fining compounds. For all the parameters, the adjusted models showed influence of the combination of the three fining agents. Together, bentonite and PVPP have synergistic effect on the reduction in monomeric flavanol levels. Such synergistic effect was also observed with PPI and PVPP combination for the reduction in turbidity. However, for this same characteristic (turbidity), the combination of PPI and bentonite has antagonistic effect. To achieve broader wine fining objectives, the simultaneous optimization of the three response variables demonstrated the importance of the presence of the three refining agents in the following proportions: 25% PPI, 43% PVPP and 32% Bentonite. The isolated use of these additives would not result in the same effect on the three studied variables.

O consumo moderado de vinho reduz significativamente os riscos de doenças cardiovasculares. Este efeito é atribuído aos polifenóis presentes no vinho, em especial ao resveratrol (3,5,4'-triidroxiestilbeno), que é uma fitoalexina encontrada em várias partes da videira, principalmente na casca da uva, assim como em outras espécies de plantas. Uvas da cultivar Cabernet Sauvignon foram submetidas à irradiação com luz ultravioleta e maceração carbônica e após fermentadas. Procedeu-se à coleta de amostras durante todo o experimento, as quais foram posteriormente analisadas quanto ao teor de trans-resveratrol através da Cromatografia Líquida de Alta Eficiência. Os resultados do trabalho demonstram que a evolução do conteúdo de trans-resveratrol foi ascendente durante as fases da fermentação. Diferenças ocorreram no final da fermentação, em que as amostras de vinhos com maceração carbônica apresentaram leve declínio, possivelmente pela atmosfera de CO2 na qual ficaram armazenadas, inibindo a formação do resveratrol. Ao final da fermentação principal a concentração de trans-resveratrol foi de 15 mg.L-1 em todos os tratamentos, chegando a 1,5 mg.L-1, em média, no final do período de estocagem.

The moderate consumption of wine reduces the risks of heart diseases significantly. This effect is attributed to the polyphenols found in the wine, in special to resveratrol (3,5,4'-trihidroxistilbene) that it is a phytoalexin found in the various parts of the vine, including in the skin of the grape, as well as in other species of plants. Grapes of cultivar Cabernet Sauvignon had been submitted to the irradiation with ultra-violet light and carbonic maceration and after fermented. It was proceeded all collection from samples during the experiment, which later had been analyzed how much to the concentration of trans-resveratrol using the Liquid Chromatography of High Efficiency. The of the content of trans-resveratrol was ascendent during the vinification phases. Differences had occurred in the end of the fermentation where the samples of wines with carbonic maceration had presentes low decline, possibly for the CO2 atmosphere in which they were stored, in this way, inhibiting the formation of resveratrol. At the end of the main fermentation, the concentration of trans-resveratrol was 15 mg.L-1 in all treatments, arriving of 1.5 mg.L-1, in average, at the end of storage period.