Soil clay mineralogy and potassium buffer capacity as potential wine quality determining factors in Western Cape vineyards

In the challenge of transforming waste into useful products that can be re-used in a circular economy perspective, winery by-products can be considered as a source of potentially bioactive molecules such as polyphenols. The wine industry generates each year 20 million tons of by-products. Kombucha fermentation is an ancestral process which allow to increase the biological properties of tea by the action of a microbial consortium formed by yeasts and bacteria called SCOBY. It belongs to the field of healthy food for which the interest of consumers is growing. The objective of this work was to propose a new functional beverage made from winemaking by-products fermented by a Kombucha SCOBY.

Table grape consumption worldwide has experienced a remarkable growth in the first two decades of the 21st century, becoming the third most consumed fresh fruit in some countries, after bananas and apples. This increase has been attributed to several reasons, including the availability of seedless grapes, which has been a key factor in the increase in consumption.

The strategy for sustainability in the wine sector of the EU refers to a set of practices and principles that aim to minimize the negative impact of wine production on the environment, social and economic sustainability. Sustainable wine production involves a range of practices that are designed to reduce waste, conserve resources, and promote the well-being of workers and communities.

European regulations describe what elements must be given in the specifications of DPO determination ; mainly production conditions, links between quality and products characteristics and the physical traits of the production area. These elements are given in the “link to terroir” paragraph relating natural and human factors, detailed product characteristics linked to the geographical area and at last interactions between product originality and the geographical area.

The aromatic quality of wines after a long aging period in bottle is one of key points for oenologists. The objective of this work is to determine the main representative aromatic compounds found in long aged wines from D.O.Ca. Rioja. This study was made by 32 wines from 1971 to 2010 vintages. Sotolon, acetaldehyde, phenylacetaldehyde, 1,1,6-trimethyl-1,2-dihydronaptalene (TDN), β-damascenone, Y-decalactone and Y-dodecalactone were determined as the most important oxidation markers by GC-MS analysis. Moreover, sensory analysis using triangular tests were performed from wines with and without the addition of the mentioned compounds. Four different concentrations of each odorant were added, as individual compounds and as mixtures. The additions were ranged from values close to the reference odour thresholds up to high level concentrations. The most identified aroma was sotolon, which is commonly associated to curry and coffee liqueur aromatic notes. Other oxidative compounds were easily detected by panellists, such as Y-decalactone (peach compote), Y-dodecalactone (ripe fruit). The mixtures of the odorants were most easily detected than the individual compounds. It should be noted that acetaldehyde and phenylacetaldehyde were rarely perceived and distinguished.