OPTIMIZATION OF EXTRACTION AND DEVELOPMENT OF AN LC-HRMS METHOD TO QUANTIFY GLUTATHIONE IN WHITE WINE LEES AND YEAST DERIVATIVES

For coopers, seasoning and toasting are considered crucial steps in barrel making during which the oak wood develops specific organoleptic properties. Seasoning, carried out in the open air, allows reducing the moisture content of the staves to between 14 and 18% (compared to 70 to 90% after splitting) while modulating the intrinsic composition of the oak wood. Toasting consists of applying different degrees of heat to a barrel for a specific period of time. As the temperature increases, oak wood produces a wide range of chemical compounds through thermal degradation of its intrinsic composition.

Smoke impact in wines is caused by a wide range of volatile phenols found in wildfire smoke. These compounds are absorbed and accumulate in berries, where they may also become glycosylated. Both volatile and glycosylated forms eventually end up in wine where they can cause off-flavors, described as “smoky”, “bacon”, “campfire” and “ashtray”, often long-lasting and lingering on the palate. In cases of large wildfire events, economic losses for all wine industry actors can be devastating.

Kalecik Karası is a domestic grape variety of Turkey, originating from Kalecik district, 80 km from Ankara. Although there is no definite evidence, it is known that it was used in wine production by many civilizations that lived in the Anatolian region, especially the Hittites. Compared to other black wine grapes, it stands out with its low tannin content, rich fruity aroma and complex structure. In good vintages, red fruits such as strawberries, cherries and raspberries stand out in the aroma profile. Although its structure is elegant, it has the potential to age and develop similar to the ‘Pinot Noir’ wine of the Burgundy region. This offers a complex aroma structure including red flowers, earth and ripe fruits.

Wine grape pomace quantitatively and qualitatively represents the most important fraction of wine waste. Namely, this by-product makes ~ 20% of the total mass of vinified grapes, and it is characterized with high concentrations of polyphenolic antioxidants, as well as grape seed oil. Hence, valorization of wine pomace, as an alternative to traditionally employed disposal, has drown considerable interest in recent years. Earlier studies were mostly focused on the extraction of phenolics, while mechanisms enhancing the extraction of lipid fraction from grape pomace, as well as their impact on the grape seed oil quality are far less investigated.

Quercetin (Q) is present in grape in form of glycosides and as aglycone. These compounds are extracted from grape skins during winemaking. In wines, following the hydrolysis reactions, the amount of quercetin aglycon can exceed its solubility value. Unfortunately, a threshold solubility concentration for quercetin in wine is not easy to determine because it depends on wine matrix (Gambuti et al., 2020).