Volatile compositions and sensorial properties of strawberry fruit wines fermented with Torulaspora delbrueckii and Saccharomyces cerevisiae in sequential and simultaneous inoculations

The effects of co-fermentation with Torulaspora delbrueckii on the composition of volatile compounds and sensory characteristics of strawberry fruit wines were investigated by fermenting strawberry pulp with T. delbrueckii in pure fermentation, as well as in simultaneous and sequential inoculations with Saccharomyces cerevisiae. E-nose analysis results showed that these strawberry fruit wines with different fermentation patterns exhibited distinct aromatic characteristics. The sensory attributes intensities of 'fruit', 'strawberry', 'sweet' and 'floral' were significantly enhanced in sequential fermentation compared to pure S. cerevisiae fermentation. Altogether, 87 volatile compounds were detected with HS-SPME-GC/MS in strawberry products, with 32 of them identified as key contributors to the overall aroma due to their high odor activity values. The sequential fermentation increased the concentration of desirable aroma-active compounds, including isoamyl alcohol, phenylethanol, isoamyl acetate, and some ethyl esters in strawberry fruit wines. The partial least squares regression analysis revealed that the fruity, floral and sweet characteristics were primarily attributed to specific aroma-active compounds, including esters such as ethyl caproate, ethyl caprylate, ethyl cinnamate, isoamyl acetate, ethyl cinnamate, ethyl 3-phenylpropionate and ethyl butyrate, as well as terpenes such as limonene, α-terpineol and nerolidol.