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- Impact of the application of vegetable proteins and yeast extract in the chemical and aromatic profile of red winePublication . Costa, V.; Caldeira, I.; Torgal, i.; Mira, HelenaFining wines are used to ensure the physicochemical stability and prevent the formation of hazes and deposits. Several fining agents (gelatin, isinglass, bentonite, etc.) are used by winemakers. These products are animal proteins or of mineral origin. However, some strict vegetarians do not accept any beverage treated with products of animal origin. Consumers requirements have given origin to new alternatives to these products, such as proteins of plant origin and yeast extracts. This work aimed to evaluate the effect of four fining agents, two vegetable proteins [pea protein and patatin, a protein extract from potatoes (Solanum tuberosum)], one yeast extract and one gelatin, on phenolic composition, volatile composition and sensory profile. The fining agents were used at the minimum (D1) and maximum dosages (D2) suggested by the respective technical sheet. Unfined wine was used as a control (D0). The red wine 2015, was produced in the Escola Superior Agrária de Santarém winery, in Tejo region. The wine is a blend of Tinta Roriz, Syrah and Alicante Bouschet. Total phenolic Index (IPT), total anthocyanins (Ant) and total tannins (Tan), colour intensity (CI) and hue were determined according the International Organization of Vine and Wine (OIV). The turbidity was also evaluated. The analysis of the volatile compounds was done by GC-MS and the sensorial analysis was performed by five expert panellists, members of the ‘Comissão Vitivinícola Regional of Tejo (CVRTejo)’. The attributes of the wine, corresponding to the visual (limpidity and colour), nose (typicity, intensity and quality) and taste senses (typicity, intensity, persistence and quality, as well as the harmony (overall judgment). According the results obtained, the vegetable proteins and the yeast extract used did not influence the wine phenolic composition: IPT (60,04±2,735), Ant (443,96±22,32 mg/L), Tan (3034,33±189,89 mg/L), CI (10,54±0,47), Hue (0,711±0,017). However, the tannin content decreased in fining wines (untreated wine 3178,47±36,24 mg/L; D1: 2980,59±238,73 mg/L; D2 2943,96±154,27 mg/L). The turbidity decreased significantly in fining wines (untreated wine 2,53±0,00; D1 1,68±0,61; D2 1,12±0,47); the gelatin was the less efficient in the decrease of turbidity (2,10±0,46). The results indicate that the fining agents did not significantly remove isobutyl alcohol, isoamyl alcohols, acetoin, ethyl lactate, diethyl succinate, 2,3-butanediol-meso and 2,3-butanediol-levo, 1-hexanol, - butyrolactone, octanoic acid, 2-metil-propanoic acid, diethyl succinate, 2-phenylethanol and ethyl vanilate. As with regards to the hexanoic acid, the ethyl 3-hydroxybutyrate and the ethyl 3-methylbutyl succinate, these decreased when the treatment was carried out with patatin, pea protein or yeast extract. These results are in agreement with those obtained in the sensory analysis, in which the tasters did not detect significant differences between the wines treated with different fining agents.
- Impacto da aplicação de proteínas vegetais e extrato de leveduras no perfil químico e aromático de vinho tintoPublication . Mira, Helena; Costa, V.; Torgal, Isabel; Caldeira, I.A colagem dos vinhos usando produtos de origem animal e mineral é uma prática muito comum, contudo as exigências de mercado têm originado novas alternativas a estes produtos, nomeadamente proteínas de origem vegetal e extratos de levedura. O objetivo deste trabalho foi comparar o efeito de três tipos de cola, proteínas de origem vegetal (batata e ervilha), proteínas de origem animal (gelatina) e extrato de leveduras, na composição química e no perfil aromático e sensorial de um vinho tinto. Os produtos de colagem foram aplicados ao vinho na dose mínima e máxima, recomendadas pelo fabricante. Os resultados obtidos mostraram que as proteínas vegetais e o extrato de levedura utilizados não afetaram a composição fenólica dos vinhos. O extrato de levedura foi o mais eficaz relativamente à Rev UIIPS. 2017; 5(2): 78-79. 79 turbidez do vinho. Foram quantificados por GC-MS quatro compostos do aroma dos vinhos designadamente o acetato de isoamilo, o 1-hexanol, o 2-feniletanol e o vanilato de etilo. O extrato de levedura contribuiu para uma maior diminuição no teor em acetato de isoamilo. As proteínas vegetais não afetaram significativamente os teores de 1-hexanol, 2-feniletanol e vanilato de etilo comparativamente com a testemunha. Na análise sensorial, os provadores não detetaram diferenças significativas entre os vinhos tratados com diferentes produtos de colagem.
- Distillates composition obtained of fermented Arbutus unedo L. fruits from different seedlings and clonal plantsPublication . Caldeira, I.; Gomes, F.; Mira, Helena; Botelho, G.The fruits of Arbutus unedo L., a shrub that grows spontaneously in countries around the Mediterranean basin, are traditionally harvested and used for the production of a distilled spirit. The main objective of this work is to compare the chemical profile of distillates obtained from fermented A. unedo fruits. Fifteen distinct distillates were obtained from ten clones and five seedlings, and they were evaluated, based on their physicochemical characteristics. An evident effect of plant propagation type (clone or seeds) on correspondent spirits analytical profile was not clearly achieved. However, the distillate composition variability seems connected to the plants variability. Furthermore, high significant effect of distillation time in all the variables measured was found, corroborating the importance of the splitting of the distillation fractions, as a good manufacturing practice. Regarding methanol, a harmful volatile compound, all the distillates obtained from the different clones or seedling fruits respected the legal limitations. From the principal component analysis, the first component seems to separate the distillates based on the pH and isobutanol, isoamyl alcohols and 2-phenylethanol which are the variables that presented the highest contributes to this component. The differences between the legal requirements and the amounts The high analytical quality, that some of the distillates showed, can be used by producers as a criterion to be considered in the future choice of plants to be implemented in new A. unedo orchards. in these distillates could result from differences in the alcoholic fermentation microbiota.