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Aims: Dueto food security problems related to animal proteins and the growing demand of non-animal-based fining agents, interest in the use of gelatine alternatives for wine fining has increased in recent years. This work studies the use of proteins of non-animal origin for the clarification of Tempranillo red wines. Methods and results: Proteins from different sources were tested: wheat (seven glutens), maize (one protein extract and one hydrolysed gluten), the yeast Saccharomyces cerevisiae (three protein extracts), and the alga Spirulina platensis (one protein extract). A preliminary physico-chemical characterisation of the proteins (solubility, isoelectric point, molecular weight) showed that some proteins presented very similar characteristics when belonging to the same source. Fining experiments, based on the principal technological parameters (turbidity of wine, volume and compactness of lees generated), were carried out on a laboratory scale, in both the presence and absence of bentonite as a co-adjuvant. Results obtained with hydrolysed maize gluten and yeast extracts showed that these proteins were particularly advantageous. The use of bentonite in combination with the proteins improved the natural sedimentation of floccules. The sensory analysis of the treated wines demonstrated favourable characteristics in all cases except from spirulina, which negatively affected sensory characteristics. Conclusions: The effectiveness of non-animal proteins is comparable to that of the traditionally used gelatine, offering advantages due, mainly, to the lower amounts of lees generated and a greater compactness. These two parameters are of great importance for winemakers, as they are associated with wine losses. Significance and impact of the study: The search for a substitute for gelatine as fining agent. |
