Mathematical modeling of fermentation kinetics: a tool to better understand interactions between Torulaspora delbrueckii and Saccharomyces cerevisiae in mixed cultures

The increasing interest in enhancing groundbreaking sensory profile of wines determined the need to select novel strains of lactic acid bacteria (LAB). Metabolic processes characterizing malolactic fermentation (MLF) lead to the production of several organic compounds that significantly impact the oenological and sensory characteristics of wines.

Context and purpose of the study. Modern viticulture is facing significant challenges due to global climate changes, spanning from extreme heat spells and water scarcity to the acceleration of grapevine’s phenological development with important consequences from budbreak to harvest.

Climate changes and the trend towards organic and more sustainable winemaking highlighted the need to use biological methodologies. The reduction in the use of SO2, the need of the reduction of ethanol content of wines and the now need to reduce or eliminate chemical phytosanitary products, have prompted the search for alternative practices.

The increasing frequency of wildfires on the West Coast of the USA is seen as a significant risk for the grape and wine industry. Research has shown that perceived smoke impact in wines correlates with increases in volatile phenols (VPs) in grapes exposed to fresh smoke.

The disruptive effect exerted by high-power ultrasound (US) on plant cell walls, natural barriers to the diffusion of compounds of interest during the maceration of red wines, is established as the reason behind the chromatic improvement that its treatment causes. However, sometimes this improvement is not observed, especially with short maceration times. The presence of a high quantity of suspended cell wall material, which formation is favored by the sonication, could be the cause of this lack of positive results since this cell wall material has a high affinity for phenolic compounds.