Impact of mannoprotein addition on malolactic fermentation by Oenococcus oeni PSU-1 in red wine during two consecutive vintages

Identifier:  imarina:9632929

Handle: https://hdl.handle.net/20.500.11797/imarina9632929

Authors:  Toraño P; Bordons A; Rozès N; Reguant C

Abstract:
Saccharomyces cerevisiae is the yeast traditionally used in alcoholic fermentation (AF) in winemaking. After AF, malolactic fermentation (MLF), principally carried out by Oenococcus oeni, converts L-malic acid to L-lactic acid, reducing acidity, increasing pH, and improving microbiological stability. This study aimed to investigate the effect of adding mannoprotein extracts with varying polysaccharide and protein profiles on MLF performance, as well as on wine phenolic composition and colour stability. The trials were conducted in Tempranillo red wines inoculated with O. oeni PSU-1 during two consecutive vintages (2022 and 2023). To evaluate the feasibility of this practice under cellar conditions, we tested different concentrations: 2 g/L in 2022 and 0.25 and 0.50 g/L in 2023. Results indicated that adding mannoprotein accelerated MLF kinetics, reducing fermentation duration compared with control wines. MLF improvement could be associated with mannoprotein consumption by O. oeni. Regarding wine quality, mannoprotein addition did not negatively affect pH or volatile acidity but influenced the phenolic profile; specifically, stable acylated anthocyanins and vitisins increased, despite a decrease in total anthocyanins. These findings confirm that low doses (0.25 g/L) of specific mannoprotein extracts can effectively stimulate MLF and modulate pigment composition in red wines.