CONTROLLED PRODUCTION OF CIDER BY INDUCTION OF ALCOHOLIC FERMENTATION AND MALOLACTIC CONVERSION

Abstract

Characterization experiments involving lactic bacteria allowed a strain of Leuconostoc oenos to be selected in terms of growth capacity at variable pH, temperature, ethanol and sulphite concentrations, malic to lactic conversion yield, acetic acid uptake and dextran production capacity. Cider was produced under controlled conditions where the effect of Kloeckera apiculata yeasts on the development of Saccharomyces cerevisiae and production of major non-volatile compounds influencing end product quality was studied. The apiculate yeast was found to produce large amounts of acetic acid and use the other organic acids; also, it hindered fermentation to a certain extent. A study of the effect of the inoculation time with L oenos as an inducer of malolactic fermentation revealed sequential inoculation of the lactic bacterium once most major sugars in the must had been depleted to be the most favourable. Using yeast cell walls boosted fermentation development, as well as degradation of malic acid and synthesis of succinic and acetic acid.