Contribution to the sensory and volatile characterization of four traditional Galician red varieties

Results indicated that cross-flow microfiltration removed similarly to fining treatments the most astringent tannins, but cross-flow microfiltration also removed up to 14 % more colour. RP-HPLC and spectrophotometric results showed that egg albumin is a softer fining treatment compared to gelatine and cross-flow microfiltration.

Red grape pomace, a waste from wine production, can be valorised by extracting polyphenols, high-added value compounds used in cosmetics or oenology. For use at an industrial level, using green extraction techniques, pomace need to be stored before being processed. The aim of this study is to test various storage conditions in order to maintain high level of polyphenols over 180 days, while keeping storage cost economically interesting. In a first step, different storage conditions (ambient temperature or cooled (4°C) temperature, anaerobic (saturation with N2) or aerobic conditions, and addition of sulphur dioxide (SO2)) were compared on small samples (1 kg) packed in plastic pockets. The quality of storage was assessed by following the optical density of the pomace extract at 280 nm (DO 280 expressed as mg/l eq gallic acid), which is an indication of the amount of remaining extractable polyphenols.

In Alentejo, south of Portugal there is a traditional way of fermenting wines in clay vessels, known as “Vinhos de Talha”. Clay vessels were traditionally impermeabilized using pine pitch, creating a barrier between the fermenting must and the clay. Due to this unusual production technology that uses of clay vessels, instead of inox or wood vessels, “Vinhos de Talha” present unique characteristics increasingly appreciated by national and international consumers when compared with wine obtained by the said traditional methods of winemaking. Although the positive consumers feedback, there is little literature about the physical-chemical characteristics of these wines (Martins et al, 2018; Cabrita et al, 2018). This work aims to characterize the volatile composition of white wines produced in clay vessels with different coatings and to contribute to the knowledge and preservation of these wines that are a unique cultural heritage. Wine samples were produced during 2019 vintage from white grapes, using the traditional technology associated to these wines.

Among the different management techniques in Viticulture, which have
been developed with the purpose of optimizing the interception of sunlight, the photosynthetic capacity of
the plant and the microclimate of the clusters, especially in varieties that show excess vigor, the management of defoliation presents great importance. The defoliation consists of the removal of leaves that cover or that are in direct contact with the curls, which can cause physical damages in the berries, and aims to balance the relation between part area and number of fruits, providing the aeration and insolation in the interior of the vineyard, as well as reduce the incidence of rot in order to achieve greater efficiency in phytosanitary treatments and quality musts.

Grapes infected with grey mould due Botrytis cinerea are widespread in vineyards during certain growing conditions.