Potential deacidifying role of a commercial chitosan: impact on pH, titratable acidity, and organic acids in model solutions and white wine
Chitin is the main structural component of a large number of organisms (i.e., mollusks, insects, crustaceans, fungi, algae), and marine invertebrates including crabs and shrimps. The main derivative of chitin is chitosan (CH), produced by N-deacetylation of chitin in alkaline solutions. Over the past decade, the OIV/OENO 338A/ 2009 resolution approved the addition of allergen-free fungoid CH to must and wine as an adjuvant for microbiological control, prevention of haziness, metals chelation and ochratoxins removal (European Commission. 2011). Despite several studies on application of CH in winemaking, there are still very limited and controversial data on its interaction with acidic components in wine (Colangelo et al., 2018; Castro Marin et al., 2021). Therefore, the aim of this work was to assess the effect of a fungoid CH on pH, titratable acidity, and organic acids content in white wine and wine model solutions. A powdered sample of CH was added to each solution from 0 to 2.0 g/L and maintained under stirring (150 rpm) for 3h at room temperature. Before and after treatment, samples were analyzed for pH, titratable acidity, and organic acids content. Based on preliminary results, the CH treatment influenced both pH and titratable acidity: pH increased from 3,17±0,03 to 3,29±0,03, while titratable acidity decreased from 5,27±0,05 g/L to 4,58±0,04 g/L as tartaric acid equivalents. In detail, reductions in tartaric acid by 5-15% and in malic acid by 7-11% were observed. At the highest dosage (2.0 g/L) the CH produced a greater removal of tartaric acid (up to 202 mg per g of CH) than of malic acid (up to 63,45 mg/g of CH). These outcomes highlighted the valuable role of an allergen-free CH-based adsorbent as an alternative adjuvant for deacidification of white wines.
European Commission. 2011. European Commission Regulation (EU) 53/2011 of 21 January 2011 amending Regulation (EC) No 606/2009 laying down certain detailed rules for implementing Council Regulation (EC) No 479/2008 as regards the categories of grapevine products, oenological practices and the applicable restrictions. Official Journal of the European Union, L19/1-L19/6.
Colangelo, D., F. Torchio, D. M. De Faveri, and M. Lambri. 2018. The use of chitosan as alternative to bentonite for wine fining: effects on heat-stability, proteins, organic acids, colour, and volatile com- pounds in an aromatic white wine. Food Chemistry 264:301–9.
Castro Marín, A.; Colangelo, D.; Lambri, M.; Riponi, C.; Chinnici, F. Relevance and perspectives of the use of chitosan in winemaking: A review. Crit. Rev. Food Sci. Nutr. 2020, 1–15
Issue: IVAS 2022
1Department for Sustainable Food Process, Università Cattolica del Sacro Cuore
2Department of Agricultural and Food Sciences, University of Bologna, Bologna, Italy
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wine; chitosan; organic acids; pH; titratable acidity