Bioprotective Effect of Pichia kluyveri and Lactiplantibacillus plantarum in Winemaking Conditions

Abstract

Consumer demand for wines free of or with reduced levels of preservatives provide new challenges for innovation in winemaking. The addition of microorganisms as bioprotective agents to avoid or reduce the sulphur dioxide (SO₂) addition during winemaking is a possible intervention strategy that could be of interest to winemakers. To this regard, a strain of Pichia kluyveri and one of Lactiplantibacillus plantarum were inoculated in a Nebbiolo red grape must, previously inoculated with a mix of microorganisms to mimic a grape must environment. The synergistic effect of the above-mentioned strains with no, low (1 g/hL) or moderate (3 g/hL) addition of total SO2 was explored in two vintages (2019 and 2020). Wine fermentations were monitored for microbiological (yeasts, lactic and acetic acid bacteria populations) and physicochemical attributes (standard chemical parameters, chromatic characteristics, phenolic and aroma compounds). Microbiological analyses showed a decrease of undesired microorganisms, namely Acetobacter aceti and Hanseniaspora uvarum, independently from the strain used, while this decrease was faster when starter cultures were combined with SO₂. Chemical analyses revealed a decrease of acetic acid and ethyl acetate in the bio-protected wines. The bioprotective ability of the starter cultures was confirmed in both vintages. This study reveals new knowledge about the use of P. kluyveri and L. plantarum as bioprotective agents in winemaking and could assist to reduce the use of SO2 in the first steps of wine production.