Joint Antibacterial Effect of p-Coumaric Acid and Sodium Metabisulfite on Lacticaseibacillus paracasei AT45 in Wine

Background and goals Sulfites are widely used as preservatives in winemaking because of their antimicrobial and antioxidant activities. Nevertheless, in recent years, a negative perception has developed toward sulfites in wine due to their undesirable effects on human health. The resulting increase in consumer demand for wines with low sulfite content is pushing the winemaking sector to develop new practices. The use of phenolic compounds has been proposed to reduce or eliminate the use of sulfites in wine. This work evaluates the joint effect of p-coumaric acid and sodium metabisulfite against Lacticaseibacillus paracasei AT45, a wine-detrimental lactic acid bacterium, in terms of antibacterial activity and prevention of biogenic amine formation. In addition, the influence of malolactic fermentation on the antibacterial effect of this combinations was assessed.

Methods and key findings A complete loss of L. paracasei AT45 viability was observed after individual supplementation of wine with p-coumaric acid or sodium metabisulfite at 400 and 80 mg/L, respectively. The effects of combinations of p-coumaric acid and sodium metabisulfite at various concentrations were evaluated using the checkerboard strategy. The results showed that the viability of L. paracasei AT45 substantially decreased compared to the control when it was inoculated at a concentration of 10³ or 10⁷ colony forming units/mL in wine with or without malolactic fermentation, indicating an additive or synergic effect of the combinations. In all assayed conditions, histamine and tyramine production were not detected.

Conclusions and significance The use of p-coumaric acid as an additional antibacterial agent in wine could substantially reduce the total concentration of sodium metabisulfite, thereby avoiding negative effects of sulfites in wine.