Probiotic alcohol-free beer made with Saccharomyces cerevisiae var. boulardii

For brewers, alcohol-free beers (AFBs) are an economically attractive segment of the beer market. At the same time, it is a category of beer that allows breweries to offer innovative products to customers. So far, the use of probiotic yeast in AFB production has not been studied. In this work, the growth characteristics of probiotic yeast in the presence of wort sugars, ethanol and iso-α-bitter acids were quantified. The highest specific growth rate (μ) of probiotic yeast was observed on glucose (0.44 ± 0.03 1/h at 30 °C), while on maltose and maltotriose it was lower by 34 and 89%, respectively. Ethanol (5% v/v) and iso-α-bitter acids (50 IBU) decreased μ on glucose (30 °C) by 20 and 23%, respectively. Response surface methodology was used to identify the main fermentation conditions affecting the formation of esters and higher alcohols. Statistical analysis of the experimental data revealed that the fermentation temperature and pitching rate had the most significant effects on flavour formation. High pressure processing was shown to be a suitable method for inactivating the probiotic yeast.