In-Depth Characterization of the Volatile Aroma Profile and Other Characteristics of White Wine Produced by Sequential Inoculation with a <i>Lachancea thermotolerans</i> Starter Yeast Strain

The yeast <i>Lachancea thermotolerans</i> has the ability to produce notable amounts of lactic acid and reduce alcoholic strength in fermentation, so it has a considerable potential for mitigating negative impacts of climate changes in winemaking. In this study, a treatment with <i>L. thermotolerans</i> and <i>Saccharomyces cerevisiae</i> in sequential inoculation was compared to a control <i>S. cerevisiae</i> monoculture fermentation of Malvazija istarska (aka Malvasia Istriana) white grape must. Standard physico-chemical parameters of the obtained wines were determined by the OIV methods. Targeted (GC/FID and GC/MS) and untargeted (GC×GC/TOF-MS) gas chromatographic techniques were combined for the analysis of volatile compounds. Phenolic compounds were analyzed by UPLC/QqQ-MS/MS, and proteins by RP-HPLC-DAD, while a sensory analysis of wines was performed by a panel of trained and certified tasters. <i>L. thermotolerans</i> co-fermentation treatment increased the concentration of lactic acid and decreased alcoholic strength. <i>L. thermotolerans</i> increased the concentrations of geraniol, β-ionone, isobutanol, isobutyric acid, ethyl isobutyrate, several major acetates, ethyl lactate, and diethyl succinate, followed by many minor compounds. This wine also contained more hydroxycinnamoyl tartrates, while control <i>S. cerevisiae</i> wine had higher levels of free hydroxycinnamates. The effects on PR proteins were minor. <i>L. thermotolerans</i> co-fermentation slightly enhanced the sensory perception of tropical fruit, herbaceous, tobacco, and buttery odor notes, as well as fullness of body. With the largest number of identified volatile compounds up to date and other results obtained, this study contributes to the better understanding of oenological and especially aromatic potential of <i>L. thermotolerans</i> in white wine production.