Enzymes for Aroma and Mouthfeel Enhancement
Katie Scully Specht
Scott Laboratories
2220 Pine View Way
P. O. Box 4559
Petaluma, CA 94955-4559
Summary: Selected enzymatic activities can have positive and negative effects on
the mouthfeel and aromatic characteristics of red and white wines.
Different
enzymatic applications and their effects are examined.
1) For white must treatment: Select an enzyme low in cinnamyl esterase
Standard pectinases can be used in white must to release aroma and
aroma precursors trapped by pectin. Unfortunately, standard pectinases,
under some conditions, may have the ability to produce undesirable
aroma precursors.
For aromatic white varieties it is best to select an
enzyme preparation low in cinnamyl esterase.
Cinnamyl esterase takes certain phenolic precursors and converts them
cinnamic acids that can then be converted by yeast into the unpleasant aroma,
vinyl-4-phenol. The conversion of the phenolic precursor into vinyl-4-phenol is
dependent on the enzyme as well as the yeast. If the yeast lacks the ability to
convert cinnamic acid into vinyl-4-phenol as is the case with POF- wine yeast
strain such as K-1 or VL1, the unpleasant aroma will not occur regardless of the
enzymatic treatment. Choosing an enzyme preparation for the treatment of
white must low in this side activity will allow flexibility in selecting from a wider
variety of yeast.
Commercial preparations include: Scottzyme Cinn-Free
2) For white wine treatment: Use an enzyme with beta-glucosidase activity.
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Aromatic grape varieties contain large amounts of ‘free’ and ‘bound’ terpenols.
Terpenols in their ‘free’ form can be described as ‘fruity’ and ‘floral’. They are
also one of the compounds responsible for enhancing varietal characteristics.
‘Bound’ terpenols are non-volatile precursors of these aromatic compounds. The
ratio of ‘free’ and ‘bound’ terpenols depends on the fruit variety.
Using an
enzyme that is able to cleave ‘bound’ terpenols from the sugar that binds them
will result in more aromatic wines.
Treatment with a beta-glucosidase preparation is most effective in wine because
this enzyme activity is inhibited by glucose. Carefull monitoring of the aroma
development is important when using beta-glucosidase preparations since
overtreatment can result in bitter wines. Yeast strains, such as the VL1, have
naturally high activities of the beta-glucosidase that are not inhibited by glucose.
Commercial preparations include: AR2000
3) For accelerated maturing of white and red wine on lees: Use an enzyme with
beta-glucanase activity.
Beta-glucanase activity facilitates the release of polysaccharides from yeast.
Polysaccharides form complexes with certain polyphenolic components of red
wines contributing to fuller, more rounded wines. In white wines studies show that
the use of a beta-glucanase leads to significant and faster increase in the
amount of polysaccharides from the yeast cell wall. The effect of this enzyme
treatment is a shorter and more desirable sur lie aging.
It should be noted that beta-glucanase preparations are commonly used in
other countries, however, they are currently not approved for use in wine by the
ATF. These preparations are sourced from Tricoderma and only enzymes coming
from Aspergillus niger have ATF approval.
4) For better mouthfeel and improved aromas in red wines: Use enzyme
preparations selected for their ability to enhance color, tannins and polyphenols.
There
are
several
enzyme
preparations
available
that
improve
the
characteristics of red wines when used during fermentation. Some preparations
are pectinases with acid-stable protease side activities and other preparations
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are pectinases with hemicellulase and cellulase side activities.
Before an
enzyme is selected for use in reds, it must be pre-screened by the supplier for its
ability to improve (or at least not destroy color). Standard preparations high in
glycosidase (sugar cleaving) activities will destroy anthocyanin stability and lead
to color loss.
Although increased color is not always observed in treatment with so called
‘color enzymes’, there generally is a positive effect in the mouthfeel and aroma
of treated wines. The side activities in these preparations facilitate the early
release of less aggressive tannins that lead to less astringent wines. The release
of anthocyanins, polysaccharides and tannins by direct and indirect action result
in bigger, more balanced mouthfeel. Some preparations have been shown to
limit the extraction of C6 compounds that are responsible for herbaceous notes.
Commercial preparations include: (a) Scottzyme Color PRO (contains protease);
(b) Scottzyme Color X and Lallzyme EX (contains cellulase and hemicellulase)
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