Simultaneous and sequential fermentations with yeast and lactic acid bacteria in apple juice

A complex substrate, reconstituted concentrated apple juice, was used for t esting the principal processes during yeast and malolactic bacteria ferment ations. Interactions between microorganisms were studied based on two contr olled inoculation procedures, and at different fermentation temperatures. T emperature had a more important effect on yeast growth than the presence of malolactic bacteria in the medium. Acceleration of the death phase of the bacterial population was detected at increased temperatures. In all cases, malic acid degradation was affected by the fermentation temperature. When e xperiments were carried out with simultaneous inoculation, acidification of the medium took place at both temperatures tested (15 degrees C and 22 deg rees C), that was not observed when the malolactic bacteria were inoculated after completion of alcoholic fermentation by yeasts.