Use of yeast biocapsules as a fungal-based immobilized cell technology for Indian Pale Ale-type beer brewing

Immobilized cell technologies (ICT) have been used in wort fermentation, beer maturation, or production of alcohol-free or low-alcohol beer. The purpose of ICT is to restrict intact cells to a specific location while allowing biological function. It improves cell stability, operational flexibility, and control in brewing, as well as ease in executing continuous operations. We investigated the use of yeast biocapsules for Indian Pale Ale (IPA) type beer wort fermentation, a novel ICT in brewing. Yeast biocapsules are a spherical yeast immobilization system in which yeast cells are encapsulated and connected to the hyphae of an inactivated hollow filamentous fungus pellet. Fermentations with yeast encapsulated in alginate beads, as the standard immobilization practice, and in free (non-immobilized) forms were carried out in parallel. We found that yeast biocapsules are a better option for cell reutilization than alginate beads, but worse for beer must clarity. Beer brewed with yeast biocapsules differed in concentration for five volatile compounds (acetaldehyde, diacetyl, ethyl acetate, 1,1-diethoxyethane, and isoamyl alcohol) and three sensory characters (persistency of the foam, malt, and yeast character). KEY POINTS: • Yeast biocapsules were investigated for beer wort fermentation • Biocapsules improve cell reutilization but are limited for beer clarification • Beer brewed with biocapsules is chemically different than conventional beer • Most sensory features did not differ between biocapsule and control beer.

Using an electronic nose and volatilome analysis to differentiate sparkling wines obtained under different conditions of temperature, ageing time and yeast formats

Effect of yeast inoculation format (F), temperature (T), and "on lees" ageing time (t) factors were evaluated on the composition of sparkling wines by a quantitative fingerprint obtained from volatile metabolites and the response of an electronic nose (E-nose). Wines elaborated according the traditional method at 10 and 14 °C, free cells and yeast biocapsules formats were monitored at 15 and 24 months of ageing time. Sixty-six volatiles identified and quantified in the eight sampling lots were subjected to a pattern recognition technique. A dual criterion based on univariate (ANOVA) and multivariate analysis (PLS-DA) through the variable importance projection (VIP) values, allowed to identify ten volatiles as potential markers for T factor, eleven for t and twelve for F factors. The discriminant models based on E-nose dataset enable a 100% correct classification of samples, in relation with t and F factors and the 83% for T factor.