Aroma Comparison of Passion Beer Fermented by Different Yeasts Based on Headspace Phase-ion Mobility Spectroscopy Technology

Yeast strains have a significant impact on the flavor and quality of beer. In this paper, passion beer was brewed with pearson wort, hops, yeast, passion juice and brewing water as raw materials. The volatile aroma components of passion beer brewed with different yeasts (S-04, US-05, S-33, CS31 and CN36) were analyzed by gas chromatography-ion mobility spectrometry (GC-IMS) technology. Principal component analysis (PCA) and orthogonal partial least-squares discrimination analysis (OPLS-DA) were used to distinguish passion beer brewed by different yeasts. The results showed that 37 volatile aroma compounds were detected by GC-IMS, including esters (16), alcohols (8), aldehydes (6), ketones (4), acids (2) and olefins (1). PCA showed the cumulative contribution rate of the PC1 and PC2 components was 60.6%. OPLS-DA results showed 68.1% of the total difference, and 17 flavor compounds contributed significantly (VIP>1), including acetic acid, ethyl octanoate, acetion, ethyl hexanoate and so on. The characteristic flavor substances for S-04 fermented fruit beer was acetic acid and 2-pentanone, characteristic flavor substance for US-05 was methyl butyrate, characteristic flavor substance for S-33 was acetoin, characteristic flavor substances for CS31 were ethyl octanoate, ethyl hexanoate, 3-methyl-1-butanol and 1-butanol, and the characteristic flavor substances for CN36 were isobutyl acetate, propyl acetate and ethyl propanoate. The research results can provide a scientific basis for the selection of yeast suitable for the production of passion beer.