Influence of weather and climatic conditions on the viticultural production in Croatia

Fining is a technique that is used to remove unwanted wine components that affect clarification, astringency, color, bitterness, and aroma. Fining involves the addition of adsorptive or reactive material in order to reduce or eliminate the presence of certain less desirable wine components and to ensure that a wine remains in a particular stable state for a given period of time Recently concerns have been raised about the addition of animal proteins, such as gelatin, to wine due to the disease known as bovine spongiform encephalopathy (Mad Cow disease). Although the origin of gelatins has been moved to porcine, winemakers are asking for substitute products with properties and application protocols similar to the traditional animal-derived ones, making the use of plant-derived proteins in fining a practically viable possibility. As a consequence, various fining agents derived from plants have been proposed, including proteins from cereals, legumes, and potato.

Context and purpose of the study. Leaf osmotic adjustment (i.e., active accumulation of osmolytes in the cells) has been reported in grapevines in response to drought and as a natural process throughout the growing season (seasonal osmotic adjustment).

ulfur compounds in wine have been studied for several years due to their impact on wine flavour, but the role of polysulfides is a recent topic. Polysulfides in wine are formed when two sulfhydryl groups oxidize, especially in presence of elemental sulfur or metal catalysts from field treatment residues (Ugliano et al. 2011). These compounds are odourless, but can degrade during storage and affect the wine quality. The mechanism of their formation is still largely unknown but different chemical and biochemical pathways have been suggested. Disulfides from cysteine (Cys) and glutathione (GSH) have been revealed in model wines (Kreitman et al. 2016) and more recently also higher polymerized forms in real wines (Van Leeuwen et al. 2020). Volatile varietal thiols like 3-mercaptohexanol (3MH) and 4-mercaptopentanone (4MMP) – flavour compounds with tropical or fruity notes – could undergo similar reactions, also with Cys and GSH, subsequently losing their flavour property (fate). Even more concerning is the possible release of H2S from polysulfides during storage, leading to undesired off-flavours (Sarrazin et al. 2010).

The increasing demand for healthier, more transparent, and sustainable wine products has prompted the need for innovative solutions to optimize the wine health value chain.

The outer waxy layer of plant aerial structures, known as the cuticle, represents an important trait that can be targeted to increase plant tolerance against abiotic stresses exacerbated by environmental transition. The MIXTA transcription factor, member of the R2R3-MYB family, is known to affect conical shape of petal epidermal cells in Anthirrinum, cuticular thickness in tomato fruit and trichome formation and morphology in several crops. The aim of this study was to investigate the role of the grapevine MIXTA homologue by phenotypic and molecular characterization of overexpressing and knock-out grapevine lines.