The Douro region: wine and tourism

Candida zemplinina (synonym Starmerella bacillaris) is frequently isolated in grape must in different vitivinicultural areas. The enological significance of C. zemplinina strains used in combination with S. cerevisiae has been demonstrated, being wines produced by the above-mixed starter, characterized by higher amounts of glycerol and esters.

The quantity and distribution of polyphenols in musts play a fundamental role in the white winemaking. This is because these substances are exposed to oxidation reactions, which are catalysed by the polyphenol oxidase (PPO), leading to a decrease in the quality of the wines produced. PPO is inactivated by SO2, but currently, due to the restrictions of the legislation, other methodologies are being investigated. Ultra-High Pressure Homogenization (UHPH) is a non-thermal physic technology that exerts an ultrahigh pressure pumping (>200 MPa) of a fluid through a valve in a continuous system.

The first South African wine was made by Jan van Riebeeck on the second of February 1659. His initial determination to produce wine at the Cape refreshment station was continued by other governors

One of the major determinants of wine quality is the aroma. Wine aroma is the human perception of the matrix of grape and yeast derived volatiles and their interaction that contribute to flavour wine. Most common are higher alcohols, ester and aldehydes. In previous studies the formation of characteristic volatile compounds have been linked to the metabolism of branched-chain and aromatic amino acids
(BCAAs) in synthetic grape must. Here we report on an investigation to assess the impact of the initial amino acid concentration on the production of aroma compounds by the industrial yeast VIN13 grown in both synthetic and real grape musts.

Oxygen transfer rate (OTR) is a technical property of closure, and it modulates the oxygen supply to the wine during its bottle aging. It’s an important parameter to take into account in the analysis of wine aroma evolution. OTR distribution is well documented for new closures, but little research has been published on its determination for aged closures. Initial oxygen release after bottling impacts the composition of wines during the first years of storage), but the link between OTR, sensory perception and aroma composition after many years of aging has not yet been clearly studied.