Chitosan Film as a Replacement for Conventional Sulphur Dioxide Treatment of White Wines: A 1H NMR Metabolomic Study

Chitosan-genipin (Ch-Ge) films have been proposed for the replacement of sulfur dioxide (SO2) in white wines preservation to circumvent the adverse health consequences caused by SO2 intake. To assess the effects of different-sized Ch-Ge films (25 and 100 cm(2)) on wine composition compared to SO2-treated and untreated wines, nuclear magnetic resonance metabolomics was applied. Relative to SO2, 100 cm(2) films induced significant changes in the levels of organic acids, sugars, amino acids, 5-hydroxymethylfurfural, among other compounds, while 25 cm(2) films appeared to induce only small variations. The observed metabolite variations were proposed to arise from the mitigation of fermentative processes, electrostatic interactions between acids and the positively charged films and the promotion of Maillard and Strecker reactions. Qualitative sensory analysis showed that wines maintained overall appropriate sensory characteristics, with 100 cm(2) film treated wines showing slightly higher attributes. Based on these results, the possibility of using Ch-Ge films as a replacement for SO2 treatment is discussed.