Research Information System
Lecture Note, pp.1-9, 2025
Azerbaijan State University of
Economics (UNEC)
Department of "SABAH
GROUPS"
Subject: Alcoholic and non-alcoholic
beverages
Lecturer: PhD in agrarian, Associate Professor: Sadigov
Ramil Ali
TOPIC 3: Alcoholic Fermentation
Introduction
Mankind
has harnessed the abilities of yeast in brewing and bread making since the
beginning of recorded history, and yeasts are probably one of the earliest
organisms to be domesticated. However, it was only clearly established in the
mid nineteenth century that conversion of glucose and fructose to ethanol and
carbon dioxide (fermentation) is a microbial process. Pasteur, in around 1876,
showed that fermentation did not arise spontaneously and isolated the yeasts
responsible for it. He also demonstrated the effect of oxygen on the
assimilation of sugar as well as the production of secondary products by
fermentation, i.e. glycerol and carbon dioxide. As noted in Chapter 2.1, the
most significant species involved in winemaking and brewing are Saccharomyces
cerevisiae. According to Ribereau-Gayon and coworkers (2000a), after investigating
the delimitation of winemaking species, all the strains of ‘bayanus’ isolated
in their study were found to belong to the species S. cerevisiae. On the other
hand, yeast called ‘uvarum’ principally belong to the species S. bayanus. In
short, yeast species involved in commercial fermentations for wine and beer comprise
a very large number of genetically similar strains, with varied technological
properties. Yeast strain can affect the rate of fermentation, the efficiency
and success of conversion of sugar to ethanol, and the nature and quantity of
by-products.