Agriculture Reference
In-Depth Information
Table 7.5
The diversity of microorganisms in winemaking
Microbial roup
Representative organism
Significance
Fungi
Yeasts
Saccharomyces cerevisiae,
Saccharomyces baya-
nus, Pichia anomala,
Dekkera/Brettanomy-
ces, Hanseniaspora
uvarrum
Alcoholic fermentation;
autolysis; sensorial mod-
ification to aroma and
mouth feel. Production
of spoilage caharacters
Moulds
Botrytis cinerea
Contribute to the produc-
tion of dessert style
wines, imparting
viscosity, sweetness and
complexity. Spoilage of
grapes by bunch rots
Bacteria
Lactic acid bacteria
Oenococcus oeni, Pedio-
coccus spp.
Preferred organism for
malolactic fermentation,
contributes to improved
sensorial attributes, de-
acidification, spoilage
Acetic acid bacteria Acetobacter aceti, Gluco-
nobacter spp.
Production of off flavour
and taint compounds
Miscellaneous
Bacillus, Actinomyces,
Streptomyces spp.
Production of taint
compounds such as
triichloroanisole
Viruses
Bacteriophage
Inhibition of malolactic
fermentation
acids and formation of glycerol that elicits specific mouth feel qualities. Bacteria
are also important micro organisms associated with wine production and contrib-
ute to the development of positive and deleterious aroma and mouth feel properties
of wine. Yeast and bacteria may also contribute to wine spoilage and many facets
of wine production are aimed directly at controlling unwanted growth of spoilage
organisms (Schmidtke
2003
; Iland et al.
2007
). This section will present a brief
synopsis of the production aspects of wine microbiology; for a discussion on wine
spoilage by yeasts the reader is directed to the review by Malfeito-Ferreria (Mal-
feito-Ferreira
2011
), and bacterial spoilage is presented in the paper by Bartowsky
(Bartowsky
2009
).
Yeast Growth
Assuming grapes are of sound quality the growth of organisms within juice and
must commences at harvest and the contribution of indigenous berry organisms to
the sensory properties of wine is considerable. A plethora of organisms exists upon
the berry surface and the reader is directed to recent reviews for further in-depth
discussion (Barata et al.
2012
). The yeasts involved in winemaking are limited by
the environmental conditions associated with the product. Thus, while some species
