Chemistry Reference
In-Depth Information
9.2.8
Production of winemaking enzymes
9.2.8.1
Enzymes produced through fermentation
To produce the enzymes used in winemaking, selected strains are cultivated in fermentors
under aerobic conditions.
A. niger
for the production of pectinases and β-glycosidases,
T. harzianum
in the case of β-glucanases and
L. fermentum
in the case of urease.
A well-defined composition of the growing medium induces optimal production of the
desired enzymatic activities. For example, a growing medium rich in pectin induces the
microorganisms to secrete pectinases (pectolytic enzymes) into the media.
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After fermen-
tation, the pectinases and enzymatic side activities are isolated by centrifuge, ultra filtration
and concentration. During these stages microorganisms are completely eliminated from the
end product.
9.2.8.2
Other types of production for enzymes used in winemaking
Lysozyme is a naturally occurring protein discovered by Fleming in 1922. Hen egg white
(HEW) lysozyme is a well-known compound that has been used in pharmaceutical compo-
sitions and food since the 1950s. The product is separated from HEW with an ion exchange
resin then purified and dehydrated.
9.2.9
Winemaking enzymes composition and formulation
9.2.9.1
Principal activity
The main activities in winemaking enzyme formulations are derived from the pectinase
family. They include pectin lyase (PL), pectin methyl-esterase (PME) and polygalacturonase
(PG). PL-type activity, known as de-polymerizing, cuts the pectin chain between two methy-
lated galacturonic acids, while the PG prefers a non-methylated substrate. PME activity
does not depolymerize the pectin chain but releases a methanol molecule from galacturonic
esterified acids. It eases the action of PG.
Pectinases, by breaking down pectin, do provide a number of obvious technical ad-
vantages, such as accelerating the pre-fermentation stages, increasing free run juice yield,
enhancing clarification and pressing, leading to an overall improvement in the grape must
quality with increased aroma and polyphenols concentrations.
Pectinase activity units
Today, each enzyme producer uses their own pectinase activity measuring method and unit.
These units mainly constitute a way for enzyme producers to compare different products
from their own production and are used for product standardization and quality control
procedures. Different analytical protocols have been developed and are standardized with
different pectin sources showing degrees of methylation different from grape pectin. These
measures do not provide an indication of the enzyme efficiency in winemaking. The
efficiency of an enzymatic preparation in winemaking is strongly related to the presence
of side activities, as the main pectinase activity alone does not ensure all benefits. For this
reason, enzymes' efficiency in winemaking ought to be checked through application trials
during the development phase of the product.
It is not possible to compare products from different origins based on the activity level
provided by the supplier on the product label or specification sheet.
