From chemistry of materials to the wine cellar

Apertura_portaleWhat happens if chemistry of materials is involved in issues concerning wine-making techniques? Probably new solutions to old problems emerge. These solutions are identified through scientific and experimental approaches, which differ from the ones which are typically used in wine-making research.
So, in a nutshell, we may introduce the meaning – and at the same time the purpose – of Molecular Wine, a project of industrial research which will last for two years, currently in progress and funded by Veneto Region, which has allocated more than 600,000 Euros for it.
The University of Verona (Veneto), with its Department of Biotechnology, is the seat of the realization for this project.
In particular, at the Operating Unit of Chemistry of Materials, directed by Dr. Fabio Piccinelli, a research for preventing protein casse is in progress. This project concerns white wines, in collaboration with the research group led by Stefano Enzo, Professor in the Department of Chemistry and Pharmacy at the University of Sassari (Sardegna).

Critical issues related to the use of bentonite

In white wines, the protein instability can produce turbidity after bottling, so causing an exclusively visual problem. This defect in itself is absolutely not dangerous for consumer’s health, but it decreases the attractiveness of the product, so negatively influencing purchasing decisions. This problem is usually solved through a stabilization process before bottling, which involves a treatment with bentonite.
Professor Angelo Spena of the University of Verona, scientific director of Molecular Wine, explains the first positive result achieved thanks to this project: the Molecular Wine Bentonite.
Professor Spena underlines: “Bentonite is clay used in different industrial processes, and has been used in oenology for about seventy years, in order to obtain protein stabilization of white wines. Although it is widely used, this is not a completely satisfactory solution to the problem, as it absorbs, alongside with the proteins which must be removed, a rather unpredictable share of aromatics, consequently depleting the olfactory complexity of the final product. So, the typicality of wine is negatively affected, even more when the vinified grapes are aromatic or semi-aromatic. In addition, the use of bentonite involves the loss of a percentage of 5-10% in the overall volume of treated wine, which remains trapped in the meshes of clarifying agent at the end of the process. So, the considerable problem of disposal of the waste clarifying agent emerges. In other terms, bentonite, after being used in cellar, is not recyclable and forms waste which must be disposed of in specific ways, and therefore it is a cost for the company“.
In the era of ecological sustainability, often used by the companies as a marketing value, too, these are not captious arguments. In particular, as Professor Spena pointed out wittily, “Winemakers are in a hurry“, and often, in order to be sure that their product will be stable after bottling, they tend to use bentonite in excess of the actual needs of the specific wine.

Higher efficiency, lower quantitative

The project Molecular Wine aims at reducing all the problems related to the use of bentonite in oenology.
Professor Spena keeps on explaining: “Molecular Wine Bentonite is produced from the commercial one, which is ground with a ball mill in order to modify its morphology and structure. This treatment, whose parameters were accurately defined, brings about an increase in the mesoporous component, that is to say its pores with diameter between 2-5 and 50 microns“.
Some tests for assessing the efficiency of this bentonite in absorbing the proteins of the wine were carried out by comparing the same material before and after the milling treatment. Professor Spena specifies: “We assessed in a sample wine the ability to bind egg albumin and thaumatin, a protein which is structurally similar to the main proteins of wine. The absorbing capacity resulted to be higher by about 25%, compared to the one of the common bentonite. We also tested the ability to absorb the proteins present in a white wine, so confirming the improvement“.
Basically, the benefits of using Molecular Wine Bentonite reside in the possibility of using lower amounts of adjuvant, thus reducing the losses of wine, processing costs and the ones concerning disposal.

To each one his (or her) own oole

Molecular Wine Bentonite is now subjected to the patenting process.
Professor Spena explains: “The demand for industrial patent deposited in the Ufficio Brevetti e Marchi della Repubblica Italiana (Patent and Trademark Office of Italian Republic) is based upon rigorous scientific data, obtained thanks to methods of Chemistry of Materials and Biological Chemistry. The oenological experimentation is carried out by another Operating Unit of the project and/or company which will want to use this product for commercial purposes. In this sense, the patent strategy agreed with Europatent (Verona, Veneto) involves an articulation of intellectual property in patents based upon properties of the matter as well as derived patents from the invention”.

But there is more than this

Molecular Wine does not deal with bentonite only.
Besides studies concerning modified protease (see box), the experts are working on new oenological silica-based stabilizers. Unlike bentonite, these compounds at the end of each use can be regenerated by means of treatments at high temperatures and then reutilized. Other materials, too, are tested. They are studied according the methods of the so-called chemical of impurity, such as titanium and yttrium. Finally, possibility of modifying some enzymes is assessed. These enzymes come into play in the release of particular aromas bound in musts, inactive from a sensorial viewpoint. Thus the final bouquet is modulated. In addition, the finalizing of an alternative method to hot bath is studied. This method allows assessing protein stability in white wines, based on the use of specific antibodies.

(in a box) Plan B: the proteases
Another line of research which is studied for the project Molecular Wine is aimed at obtaining specific proteases which degrade the proteins of the wine that can bring about possible turbidity. But Angelo Spena explains: “It will not be easy to obtain results in this direction, because of the stability which characterizes the proteins of wine and their quantity, too. We should produce very active and operative proteases”.

Article by Elettra Silviato

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