Co-fermentation of lactic acid bacteria and S. cerevisiae for the production of a probiotic beer: Survival and sensory and analytical characterization

Abstract

The effects of boiling stage hopping or dry hopping methods; the use of Bobek or Crystal hop varieties; and the usage of just Sacharomyces cerevisiae yeasts or co-fermentation with Lactobacillus plantarum bacteria on the production of a probiotic beer have been studied. Only the cell viability levels registered for Lactobacillus plantarum bacteria in those beers produced by dry hopping, after an initial inoculation of 10 million cells per mL in both beers hopped during the boiling stage and in dry-hopped beers, were higher than those generally considered as minimum to provide health promoting benefits. With regard to polyphenols, higher concentrations were generally obtained in the beers produced by co-inoculation, whereas with respect to volatile compounds, co-inoculation with Lactobacillus plantarum and the employment of the dry hopping method with Bobek hops resulted in the beers with the highest contents. The sensory profile of the beers was clearly influenced by the hopping method, so that dry-hopped beers were awarded significantly higher scores with respect to certain fruity (stone fruit and tropical fruit, p < 0.05) and floral descriptors (p < 0.05), while they were ranked at a lower level regarding their cereal and toasted descriptors. The hopping method was the most influential on the composition and sensory properties of the final beers whereas the co-fermentation did not substantially modify any of them.