Untangling the wine metabolome by combining untargeted SPME-GCxGC-TOF-MS and sensory analysis to profile Sauvignon blanc co-fermented with seven different yeasts

Saccharomyces cerevisiae (SC) is the main driver of alcoholic fermentation, however for aroma and flavor formation in wine, non-Saccharomyces species can have a powerful effect. This study aimed to compare untargeted volatile compound profiles from SPME-GCxGC-TOF-MS and sensory analysis data of Sauvignon blanc wine inoculated with six different non-Saccharomyces yeasts followed by SC. Torulaspora delbrueckii (TD), Lachancea thermotolerans (LT), Pichia kluyveri (PK) and Metschnikowia pulcherrima (MP) where commercial starter strains, while Candida zemplinina (CZ) and Kazachstania aerobia (KA), were isolated from wine grape environments. Each wine showed a distinct profile both sensorially and chemically. SC and CZ wines were the most distinct in both of these cases. SC wine had guava, grapefruit, banana, and pineapple aromas while CZ wine was driven by fermented apple, dried peach/apricot, and stewed fruit as well as sour flavor. Chemically over 300 unique features were identified as significantly different across the fermentations. SC wine had the highest number of esters in the highest relative concentration but all the yeasts had distinct ester profiles. CZ wine displayed the highest number of terpenes in high concentration but also produced a large amount of acetic acid. KA wine was high in ethyl acetate. TD wine had fewer esters but three distinctly higher thiol compounds. LT wine showed a relatively high number of increased acetate esters and certain terpenes. PK wine had some off odor compounds while the MP wine had high levels of methyl butyl-, methyl propyl-, and phenethyl esters. Overall, this study gives a more detailed profile of these yeasts contribution to Sauvignon blanc wine than previously reported.