The Effect of New Inhibitors on Malolactic Fermentation of Wines

This study deals with the influence of various oenological preparations on malolactic fermentation. The influence of chitosan, fumaric acid, a tannin-based (Estaan) oenological preparation and medium-chain fatty acids (MCFAs) was investigated, along with a new preparation based on a combination of selected hydroxycinnamic acids and MCFAs. Growth curves were obtained using Oenococcus oeni, Lactobacillus brevis and Lactobacillus plantarum bacteria. Experimental work was also carried out on microsamples of wine, where individual inhibitors were added to wine inoculated with O. oeni culture and an HPLC analysis was performed to measure malic acid levels. Fumaric acid had the strongest inhibitory effect on L. plantarum at a dose of 2.5 g∙L−1, while chitosan had the strongest effect on O. oeni at a dose of 2.5 mg∙L−1. P-coumaric acid in combination with MCFAs (0.4 g∙L−1 of p-coumaric acid + 10 mg∙L−1 MCFAs) and Mix (0.4 g∙L−1 of p-coumaric acid + 0.4 g∙L−1 of ferulic acid + 10 mg∙L−1 MCFA) had the strongest inhibitory effects on O. oeni and L. brevis. Finally, MCFAs had the strongest inhibitory effect on L. brevis at a dose of 1000 mg∙L−1, and Estaan had the strongest effect on L. plantarum at a dose of 25 g∙L−1.