Biomedical Engineering Reference
In-Depth Information
Chapter 6
Physiology and Biochemistry
of Sourdough Yeasts
M. Elisabetta Guerzoni , Diana I. Serrazanetti , Pamela Vernocchi,
and Andrea Gianotti
6.1
Introduction
Although baker's yeast is used worldwide as a leavening agent for the manufacture
of baked products, an overwhelming multitude of baked goods are also produced
with the aid of sourdough. These include above all breads from wheat, rye and mix-
tures thereof as well as the well-known Italian products such as Panettone, Colomba,
Pandoro and different types of brioches.
Traditional cultivation methods in combination with phenotypic and genotypic
identification adopted to characterise the yeasts of ripe dough revealed the presence
of some species belonging, especially, to the genera
Saccharomyces
and
Candida
[
1-
6
]. Their taxonomic features and diversity are described in Chap. 5. Based on
studies focused on the yeast population of sourdough, the most frequent species
were
Saccharomyces cerevisiae
and
Candida milleri
[
7,
8
] . In some cases,
Candida
milleri
accounted for 65.8% of the isolates in artisanal sourdough produced without
the addition of baker's yeast [
9
] .
This chapter is mainly focused on the description of: (1) yeast responses to phys-
ico-chemical conditions and their fluctuation during sourdough fermentation; (2)
implications of such responses for fermentation products and flavour compounds,
including quorum-sensing molecules; and (3) the production of baker's yeast and its
use in the bread-making industry.
