Comparison between a Polyaspartate based additive and conventional techniques for tartaric stabilisation

Mestrado Vinifera Euromaster - Viticulture and Enology - Instituto Superior de Agronomia

Among the various enological products authorized by the European legislation, metatartaric acid (MTA) and carboxymethyl cellulose (CMC) are the most widely used to prevent tartrate salts instability, although showing some drawbacks concerning long-term efficacy the former, and colour instability the latter. Recently, an additive based on potassium polyaspartate (KPA) has been evaluated with regards to tartaric stabilisation, to obtain the admission of its use by the European Commission in 2017. The following thesis project developed at the Research Centre of Laimburg (Italy) aims to test the stabilisation effectiveness of potassium polyaspartates (KPA) on local red and white wines, in comparison with the two most widely used additive agents (MTA and CMC) and a subtractive technique (cold stabilisation). Analysis of stability were carried out over a period of six months, as well as chemical-physical parameters (turbidity, tartaric acid, chromatic characteristics) and sensory evaluations of each treatment. Statistical analysis between all trials’ results confirmed the importance of time in recognising the different performances of the used additives aimed to inhibit the crystallisation process of tartaric acid salts, whose behaviour produced different responses with regard to tartrate stability, turbidity and sensory profile. Best results were observed in wines treated with potassium polyaspartate (KPA) and cold stabilisation, although the latter is considered to bring some drawbacks related to operating costs, thus sustainability. Storage temperature effect (35°C) on the different treatments was also evaluated, obtaining again good responses from the polyaspartate based product, although depending on the dose applied. Sensory evaluation confirmed that the debate is still current, expressing greater preference towards cold stabilisation rather than any additive treatment

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