Céline Fauveau¹, Patrice Pellerin¹ and Karien O’Kennedy^2
1DSM Food Specialties Oenology, Montpellier, France (www.dsm-oenology.com)
²Anchor Wine Yeast, Epping Industria, South Africa (www.anchorwineyeast.com)

Introduction

The principal enzymes used in winemaking are pectinases. Pectinases occur naturally in all fruit - including grapes - and are partly responsible for the ripening process. Grape pectinases are however inactive under the pH and SO₂ conditions associated with winemaking. Fungal pectinases are resistant to these winemaking conditions. The method used to produce wine enzymes is regulated by the OIV. Producers that export wine to the EU - if they use enzymes - should use products that comply with these prerequisites.

Enzyme preparations used in winemaking must comply with the specifications recommended by JECFA (joint FAO/WHO Expert Committee on Food Additives) and by FCC (Food Chemical Codex) for food enzymes. The OIV takes decisions on analysis methods and on enological applications and treatments.  Organisations such as the FDA (Food and drugs administration) in the United States of America, the DGCCRF (Direction générale de la concurrence, de la consommation et de la répression des fraudes) in France or the FSANZ (Food Standards Australia New Zealand) control the adherence to laws and/or ensure peoples’ safety.

Enzymatic activities currently authorised in winemaking

The OIV resolution, oeno 11-18/2004 (1), recognizes the importance of the following enzymatic activities: pectin lyase, pectin methyl-esterase, polygalacturonase, glycosidase, hemicellulase, cellulase and b-glucanase. The latter four types are generally present as side activities in pectinase preparations. The OIV and International Code of Oenological practices also authorised lysozyme (resolution oeno 15/2001) and the use of urease (for treatment of wines to reduce the risk of ethyl carbamate formation).

Speaking of GMO in respect to enzymes generates confusion. Genetic modification techniques only apply to productive microorganism and not to enzymes: enzymes are proteins, not living organisms. But, they can be produced by classical microorganisms or microorganisms that have been obtained by genetic modification. Thus, we can speak of an enzyme as being produced by a genetically modified microorganism as opposed to being produced by a classical microorganism.

Only targeted questions on the conditions for obtaining the productive microorganism strain for the enzyme will provide reliable information on whether genetic engineering was used. GMO certificates from an enzyme supplier must state that the microorganism used in the production of the enzyme was not genetically modified in any way, if the winery using the enzyme exports to the EU. GMO certificates that state that the product is not GMO, or does not contain any GMO’s, does not exclude the possibility that the productive microorganism was GMO.
 
Details of genetic engineering techniques and their advantages in oenological use are not discussed in this article. However, such techniques should only be used where full transparency is exercised in respect of clients and when their use is generally agreed upon in the market and amongst consumers.