Effect of sucrose, trehalose and glutamate on the resistance to ethanol of frozen and freeze-dried acclimated oenological Lactobacillus plantarum strains

BRAVO-FERRADA B; BRIZUELA N.S.; GERBINO, E.; GOMEZ ZAVAGLIA, A.; SEMORILE L; TYMCZYSZYN E,

Congreso; 52nd Annual Meeting of the Society for Cryobiology; 2015

Society for Cryobiology

Lactobacillusplantarum is one of the species most widely used for malolactic fermentation inwinemaking. Most of the strains are able to grow in the harsh wine environment,producing different metabolites that improve the organoleptic properties ofwine. For this reason, optimizing the preservation conditions of oenological L.plantarum strains is essential in winemaking.Theexposure of microorganisms to sub-lethal ethanol concentrations prior wineinoculation (acclimation) is a usual step to improve bacterial viability.However, the effect of acclimation on bacterial preservation and on theirtechnological properties has not been addressed hereto.The aim ofthis work was to investigate the effect of freezing and freeze-drying on threestrains of L. plantarum, previously acclimated in 6 and 10% v/v ethanol. Foreach condition assayed, the protectant capacity of three agents (sucrose,trehalose and glutamate) was also evaluated.Afterfreezing or freeze-drying, microorganisms were grown in synthetic winecontaining 13 or 14% v/v ethanol and pH 3.5. Acclimation increased theresistance to ethanol after freezing and freeze-drying. In addition, sucrose,trehalose and glutamate showed an adequate protective capacity as determined byplate counting and multiparametric flow cytometry.Thecombination of acclimation treatment and protective agents appears as a usefulstrategy to overcome the detrimental effects of these preservation processes,with promissory industrial applications as dehydrated malolactic starters.