2018/02/28 by Patricia A. Howe, Randy Worobo, Randy W. Worobo +1 · 1 citation
Agricultural and Biological Sciences · Medicine · #Fermentation and Sensory Analysis #Horticultural and Viticultural Research #Phytochemicals and Antioxidant Activities
paper · doi:10.5344/ajev.2018.17037
crossref issued 2018/02/28 · crossref published 2018/02/28 · crossref published-online 2018/02/28 · openalex publication_date 2018/02/28 · crossref created 2018/02/28 · crossref published-print 2018/07/01 · crossref deposited 2019/09/03 · openalex created_date 2025/10/10 · crossref indexed 2026/07/24 · openalex updated_date 2026/07/31
Conventional approaches to measuring sulfur dioxide (SO<sub>2</sub>) in wine, such as aeration-oxidation, iodometric titration, and flow-injection analysis, are known to overestimate molecular SO<sub>2</sub>, particularly in red wine because of the dissolution of weak anthocyanin-bisulfite complexes during analysis. Methods for determining molecular SO<sub>2</sub> without perturbing anthocyanin-bisulfite complexes and other weak adducts exist, e.g., headspace gas-detection tube measurements. However, it is unclear whether SO<sub>2</sub> values achieved through conventional methods (“Molecular SO<sub>2</sub>”) or nonperturbing methods (molecular SO<sub>2</sub>) provide a better measure of antimicrobial activity. In our work, white and pseudo-red wines were prepared with varying additions of SO<sub>2</sub>; the red wine was produced by spiking the white wine with an anthocyanin extract. “Molecular SO<sub>2</sub>” and molecular SO<sub>2</sub> concentration in white wines were well correlated, but “Molecular SO<sub>2</sub>” was significantly higher in red wines. Wines were inoculated with <i>Saccharomyces cerevisiae</i> strain EC1118 (Lallemand), and viability and culturability were evaluated at regular intervals. Both culturable and viable cell counts decreased significantly for treatments with 0.5 to 2.0 mg/L molecular SO<sub>2</sub> in the white and red wines, and for 0.5 to 2.0 mg/L “Molecular SO<sub>2</sub>” in the white wine, but concentrations >2.0 mg/L “Molecular SO<sub>2</sub>” were necessary to decrease cell counts in the red wine. These results indicate that anthocyanin-bisulfite complexes have negligible antimicrobial activity, and that conventional approaches to measuring “Molecular SO<sub>2</sub>” are poorly suited to predicting the microbial stability of red wines.