"Mouthfeel : Different Biotechnological Ways to
Manage it"
Laurent Dulau
Lallemand S.A., Complexe Scientifique Rangueil
Hall Gilbert Durand, B.P. 4412 – 31405 Toulouse Cedex, France
The role of polysaccharides in wine, and the role that they play in wine production and
quality, has recently attracted some attention. There is good evidence that winemakers
can use oenological and biotechnological tools to shape polysaccharide levels, and as
a consequence, the mouthfeel of a wine.
All wines contain polysaccharides that can be classified into four categories based upon
their origin:
1. Polysaccharides from fruit. Grape polysaccharides are essentially pectins and
neutral polysaccharides (arabinans, galactans and arabinogalactans) with a
molecular weight ranging from 40 to 250 kDa and which are mainly responsible for
the viscosity of the wine.
2. Polysaccharides originating from mold. The most significant polysaccharides from
this group are ß-glucans from Botrytis cinerea. These linear molecules are of the
order of 1000 kDa and play a detrimental role in the winemaking process, by
decreasing the filterability of the wine.
3. Polysaccharides
released
from
yeast
(Saccharomyces
spp.).
These
polysaccharides can be separated into two structural groups, the ß-glucans (25270 kDa) and the mannoproteins (10-450 kDa). The concentration of these
polysaccharides in wine is reported to be of the order of 0.3 to 1 gL -1(Feuillat,
1999).
4. Mono and polysaccharides produce by some lactic acid bacteria naturally found
in wines like Pediococcus spp. (in the case of “ropiness”) but also, and it has been
recently
found,
like
Oenococcus
oeni.
The
role
of
these
mono
and
polysaccharides released from Oenococcus is not clear for the moment but
could be a possible explanation for the increase in volume of wines observed
after the completion of malo-lactic fermentation.
In the following paper, the results of some recent studies will show that the winemaker has
at his disposal, different biotechnological tools such as enzyme preparations, yeast and
bacteria strains to increase the polysaccharide content of their wines. In addition it will be
explained how these specific polysaccharide fractions have a positive action of the
global quality of wines.
FIGURE 1: THE PRODUCTION OF POLYSACCHARIDES IN
SYNTHETIC MUST BY DIFFERENT STRAINS OF COMMERCIALLY
AVAILABLE YEASTS
polysaccharides (mg/l)
120
100
80
60
40
DGI299
CS2
CEG
CK
UVA
BRL97
BC
CSM
CM
PM
0
L905
20
Commercial Yeasts
Figure 1(a): Total polysaccharides as determined by HPLC. The concentration of
polysaccharides after 12 days of fermentation in synthetic must (20% sugar, 25°C),
using a range of commercially available yeasts. (Rossi et al, 1998)
polysaccharides (mg/l)
160
140
120
100
80
60
40
Bdx
BM45
DV10
K1
D47
RC212
L2056
L2226
QA23
CY3079
D254
S6U
0
71B
20
Commercial Yeasts
Figure 1 (b): Total polysaccharides determined using the modified method of UsseglioTomasset (1976). Concentration of polysaccharides obtained after 12 days of fermentation
of a synthetic must (20% sugar, 25°C), using commercially available yeasts.
Table 1: composition of the macromolecules produced by the yeast during alcoholic
fermentation in a synthetic medium (Rosi et al, 1999).
EXOCELLULAR YEAST MACROMOLECULES
Polysaccharides
(mg)
Proteins (mg)
Mannose (%)
Glucose (%)
97.9
1.30
89.2
10.2
20
0
18
0
16
0
14
0
12
0
10
08
0
6
0
4
2
0
00
L2226
BM45
Ethanol index x10
Gelatin index
Polysaccharides/10
Figure 2: Different indexes obtained after a comparative fermentation of the same must
with a high and low producer of polysaccharides
LITERATURE:
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Bourgogne. II. Evolution des macromolécules: polysaccharides et protéines, Vitis, vol.
28, 161-176
Rosi I, Gheri A. et Ferrari S., 1998, Effet des levures produisant des polysaccharides
pariétaux pendant la fermentation sur certaines caractéristiques des vins rouges, Rev.
Fr. Oeno., Septembre/Octobre, no 172, 24-26
Rosi I., Domizio P., Fia G. and Lencioni L., 1999, Production of parietal macromolecules by
Saccharomyces cerevisiae and their influence on malolactic fermentation, Les
entretiens scientifiques Lallemand, Montréal
Lubbers S., Léger B., Charpentier C. et Feuillat M., 1993, Effet colloïdes protecteurs
d’extraits de parois de levures sur la stabilité tartrique d’un vin modèle, J. Inter. Sci.
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protéique des vins au cours de l’élevage sur lies, J. Inter. Sci. Vigne Vin, 26, 239-251
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d’œnologie. A. Lonvaud-Funel (Ed.), Tec&Document, Lavoisier, Paris, 395-400
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glucidi da parte di lieviti. Vigne Vini, 1-2, 33-40
Llaubères R.M., Dubourdieu D. and Villetaz J.C., 1887, Exocellular polysaccharides from
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Usseglio-Tomasset L., 1976, les colloïdes glucidiques solubles des moûts et des vins, Conn.
Vigne Vin, 10, 193-226