Potential deacidifying role of a commercial chitosan: impact on pH, titratable acidity, and organic acids in model solutions and white wine

Abstract

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.

References

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