Influence of a malolactic starter on the quality of the cider produced on an industrial scale.

摘要

Application of starter culture technologies to induce malolactic fermentation in cidermaking was investigated. A selected indigenous cider malolactic strain (Lc2) was tested as a starter culture to assess its implementation and its influence on cider production on an industrial scale (10 000 l). Results showed that the culture, under the fermentation conditions tested, allowed successful achievement of malolactic fermentation. Analysis of L-malic acid in the fermenting apple must medium revealed a highly significant difference in the rate of consumption of this acid from the moment of bacterial inoculation when compared with that of the control. The concn. of the malolactic starter culture remained at inoculation level (106 cfu/ml) during the process, the level necessary to ensure malolactic fermentation. Thus, the cider malolactic starter culture demonstrated good adaptation to the harsh environmental conditions found in the fermenting apple must, such as low temp. and the presence of SO2 and ethanol. Several parameters were monitored during the process (sp. gr., temp., pH, free SO2 content, microbiological counts, malic acid degradation rate, lactic acid formation and levels of other major organic acids and volatile compounds) under inoculated and uninoculated conditions.