Enhancing aroma and stability in Sicilian Maiorca wheat beer: Impact of Torulaspora delbrueckii via inoculation methods

Abstract

In response to the rising demand for alternative yeasts in brewing, this study explored the potential of Torulaspora delbrueckii, a yeast known for its floral notes in winemaking, to enhance the aromatic profile of wheat beer. We developed a recipe using a 1:1 blend of Maiorca wheat malt and grain and employed different inoculation methods to compare the effects of T. delbrueckii with a traditional Saccharomyces cerevisiae fermentation. Extensive physicochemical analyses were conducted on both the wort and beer, including volatile aroma compounds, by using solid-phase microextraction (SPME) coupled with gas chromatography-mass spectrometry (GC-MS). Identification was based on spectral library matching and retention index comparison. Results were compared to descriptive sensory analysis of the experimental beers. Eighteen key volatile compounds were detected, including phenethyl alcohol, ethyl acetate, and isoamyl acetate, with T. delbrueckii enhancing fruity and ester notes, especially in co-inoculated and sequentially inoculated beer samples. The introduction of T. delbrueckii during primary fermentation increased desirable aromatic compounds such as esters (fruity, floral), phenolics, and malty notes while reducing undesirable compounds like diacetyl, octanoic acid, oxidized aromas, and aldehydes. These findings indicate that T. delbrueckii could play a beneficial role in enhancing beer stability and sensory quality.