P-13
Uptake of wort amino acids during beer production: Impact of yeast strain and
fermentation conditions. According to Jones (J. Inst. Brew., 1964 - 1969), the amino acid absorption
by Saccharomyces cerevisiae occurs sequentially in a complex medium. The
sequence would not be influenced by individual concentrations. Although this
model allows explanation, for instance, the well-known diacetyl peaks during a
brewing fermentation, no comparison with the new data issued from molecular
biology has been attempted up to now. The aim of the present work is therefore
to clarify under which conditions four amino acid families can be really
defined. For this purpose, the amino acid uptake has been monitored through
fermentation in different media, at various scales and with several yeast
strains. Taking into account available information about yeast permeases, an
improved model emerges from these experiments.
Philippe Perpète has obtained a degree in biological sciences in 1990 at
the Facultés Notre Dame de la Paix in Namur (Belgium), a degree in chemical
sciences in 1992 from the same university and a PhD thesis in 1999 from the
Université catholique de Louvain. His thesis was dedicated to alcohol-free beer
organoleptic problems. He worked as research assistant from 1993 to 1999 in the
Unit of brewery and food sciences headed by Prof. Sonia Collin. He is currently
professor in this research unit.
PERPETE PHILIPPE, Santos Gumer, Bodart Etienne, and Sonia Collin. Universite
Catholique de Louvain, Unité de brasserie et des industries alimentaires, Croix
du Sud, 2/7, B-1348 Louavin-la-Neuve, Belgium.