Red wine astringency: evolution of tribological parameters during different harvest dates

The mechanical strength or firmness of a fruit is considered an important parameter to characterize its state of maturity or conservation, as other parameters such as sugar level or color.

Aroma diversity is one of the most important features in the expression of the varietal and geographic identity and sensory uniqueness of a wine. Italy has one of the largest ampelographic heritages of the world, with more than five hundred different varieties. Among them, many are used for the production of dry still white wines, many classified as Protected Designation of Origins and therefore produced in specific geographical areas with well-defined grape varieties. Chemical and sensory characteristics of the aroma of these wines have never been systematically studied, and the relative diversity has never been described and classified.

The phenolic component of red wine is responsible for important elements of flavor and mouthfeel, and thus quality of the finished wine. Additionally, many of these phenolics have been associated with health benefits such as reduction of the risk of developing cardiovascular disease, cancer, osteoporosis and preventing Alzheimer’s disease. While the origins, concentrations, and chemistries of the phenolics in a finished red wine are well known, the fundamental mechanisms and kinetics of extraction of these phenolics from grape skins and seeds during red wine fermentation are poorly understood. This lack of knowledge regarding the extraction mechanisms of phenolics during red wine fermentation makes informed manipulations of the finished wine’s phenolic composition difficult.

Terroir encompasses environmental (climate, geology, soil and topography), genetic (cultivar and clone) and human factors (oenological and viticultural practices). Climate change brings about shifts in the suitability of a region for the growth of specific grapevine cultivars. This study focused on climatic and fruit parameters (berry size, weight, pH, total acidity (TA) and phenolics) to characterise the terroir effect in Vitis vinifera L. cultivars Chardonnay and Pinot Noir vineyards in the Cape South Coast region (Walker Bay and Elgin).

AIM: High pressure technologies represent a promising alternative to thermal treatments for improving quality and safety of liquid foods.