5 Use of Enological Additives for Colloid and Tartrate Salt Stabilization 151
Use of CMC for enological applications is as yet not authorized in the Euro-
pean Community but, due to their capabilities (see below), a request for their use
is in process. Through a collaborative study between theChambre d’Agriculture
de la Girondeand the Laboratory of Chemical Engineering of the University of
Toulouse, it has been shown that a sodium CMC with both a low degree of sub-
stitution (between 0.65 and 0.90), a low polymerization degree and a 99.5% purity,
at doses ranging from 2 g/hL to 4 g/hL, that is, doses 12- to 250-fold lower than
those currently under use in the food industry, is able to stabilize various red and
white wines as regard to tartrate salt crystallization (Crachereau et al. 2001). The
protective effect observed was conserved even after heat treatment of the wines
(55–60◦C over a period of time ranging from 5 to 30 days), followed by a period at
− 4 ◦C for 1 month, thus demonstrating the high thermostability of CMC compared
to that of metatartaric acid (see above). Added at a dose of 4 g/hL, CMC shows
a stabilizing effect similar to that obtained by using metatartaric acid at a dose of
10 g/hL (Crachereau et al. 2001). The stabilizing effect of CMC on tartrate salt pre-
cipitation both results from its capacity to reduce the transfer of bitartrate molecules
from the bulk (the hydroalcoholic solution supersaturated with this salt) to growing
crystals and the ability to decrease the speed with which some crystal faces grow.
Gerbaux (1996) in his PhD dissertation reported that CMC specifically inhibits the
growth of the face (010) of bitartrate crystals. In work developed in our laboratory
(Achddou, unpublished results), CMC was shown to increase the supersaturation
field of KHT in Champagne base wines, thus delaying tartrate salt precipitation.
5.3 Use of Mannoproteins to Stabilize Wines as Regard
to Protein Haze
Protein haze remains as one of the key potential instabilities in white wine pro-
duction that requires fining treatment with bentonites, animal proteins (casein and
gelatin), or bentonites used together with casein (bentocasein), or tannins used
together with gelatin (see Sect. 5.1). Haze formation is traditionally prevented by
protein removal through adsorption onto bentonites, which have been used for more
than 60 years as adsorbents in winemaking (Blade and Boulton 1988). This partic-
ular affinity of proteins for phyllosilicates is based on the commonly high specific-
surface areas associated with swelling and cation-exchange properties of the latter.
However, because this procedure alters the organoleptic characteristics of wines and
since from 5% to 20% of the wine volume treated with bentonites may be lost as
bentonite lees, there are numerous studies focusing on the mechanisms of protein
haze and the compounds that are responsible for haze in white and ros ́ewines
(Ferreira et al. 2004; Waters et al. 1996).
Other authors have searched for alternative treatments for the use of bentonites,
particularly the yeast mannoproteins owing to the fact that a systematic improve-
ment of protein stability can indeed be observed in white wines during aging on
lees in barrels (Ledoux et al. 1992). Aged on lees, new wines become decreasingly