Unravelling the potential of non-conventional yeasts and recycled brewers spent grains (BSG) for non-alcoholic and low alcohol beer (NABLAB)

Abstract

The non-alcoholic beer sector has seen steady growth in recent years and non-conventional yeasts could be a chance to produce this specialty beer. On the other hand, non-alcoholic beer with appreciated aromatic characteristics remains a challenge. In this work, 14 yeast strains belonging to 7 different species were tested to produce low-alcohol or alcohol-free beers using recycled low-sugar wort from brewers spent grains (BSG). The results showed that a strain of Lachancea thermotolerans and a strain of Torulaspora delbrueckii exhibited a fermentation evolution comparable to that of Saccharomyces cerevisiae commercial strain with a reduced ethanol (0.46, 0.57, 1.22 % v/v respectively). L. thermotolerans strains were characterized by lactic acid production and esters formation with the strain DiSVA 322 that exhibited the best aromatic and sensorial performance. T. delbrueckii DiSVA 253 showed an effective analytical profile with a peculiar sensory profile. Although Pichia kluyveri strains did not show significant fermentation evolution, the strains DiSVA 1078 and DiSVA 1079 revealed positive sensorial and analytical traits that significantly distinguished the beers for fruity/esters and sweet notes. The wort from recycled BSG resulted a favourable substrate to produce of non-alcoholic or low alcoholic beers in conjunction with selected non-conventional yeasts.