Viticulture and wine production have a historical tradition in Istria. First written document of vine cultivation in this area date since antiquity. The most wide spread vine variety in Istria is Istrian Malvasia (white variety), and it capture about 60% of total vineyard surface in Istria today.

Protein haze in white wines is a major technological and economic problem of the wine industry. Field tests were carried out in steep slope vineyards planted with Riesling grapes over 3 dry growing seasons to study the effect of drought stress on the concentration of proteins in the resulting wines. Plots suffering from drought stress were compared with surrounding drip irrigated plots. Riesling grapes were processed into wines by conventional procedures. Protein amounts of the isolated wine colloids of the stressed samples were always higher than those of the watered samples(mean watered 13.8 ± 0.44, mean stressed 17.4 ± 0.40 g 100 g-1). As a consequence, higher bentonite doses were needed to achieve protein haze stability of the drought stressed treatments.

Contribution Foam is the characteristic that differentiates sparkling wines from still wines, being the first sensory attribute that tasters and consumers perceive and that determines the final quality of sparkling wines [1]. The foaming properties mainly depend on the chemical composition of wines [2-3], and different factors involved in wine composition will have an effect on foam quality. In Spain, the sparkling wine market focuses on the production of white and rosé sparkling wine, with very low production of red sparkling wines. However, this type of wines is elaborated in countries like Australia, South-Africa, Argentina, Italy or Portugal, with a great acceptance by consumers. No studies on the foaming characteristics of red sparkling wines have been found.

Numerous studies have demonstrated the importance of irrigation in improving the grape yield and quality in areas with arid and semiarid climates, particularly in the context of ongoing climate changes. However, the introduction of irrigation in vineyards of the Mediterranean basin is a matter of debate, in particular in those of the Douro Demarcated Region (DDR), due to the limited number of available studies in this region. The present study aimed to evaluate how different irrigation deficits for 6 years would influence production and must quality in Touriga Francesa (TF) and Touriga Nacional (TN) varieties.

The interaction between tannins and salivary proteins is considered to be the basis of the phenomenon of wine astringency. Recently, some authors have revealed that some anthocyanins can also contribute to this mouthfeel sensation by interacting with proline rich proteins (PRPs). However, more studies are needed in order to elucidate the affinity of anthocyanins with these proteins.