Browsing by Author "Lerm, E."

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    Malolactic fermentation : the ABC's of MLF
    (SASEV, 2010-09) Lerm, E.; Engelbrecht, L.; Du Toit, M.
    There are two main fermentations associated with the winemaking process. Alcoholic fermentation is conducted by the yeast culture and malolactic fermentation takes place as a result of the metabolic activity of lactic acid bacteria, specifically from the genera Oenococcus, Lactobacillus, Pediococcus and Leuconostoc. Malolactic fermentation is dened as the conversion of malic acid to lactic acid and CO2 and besides deacidification also contributes to microbial stability and modification of the aroma prole. This paper aims to provide a comprehensive review discussing all the main aspects and factors related to malolactic fermentation, including practical considerations for monitoring and ensuring a successful fermentation.
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    Selection and characterisation of oenococcus oeni and lactobacillus plantarum South African wine isolates for use as malolactic fermentation starter cultures
    (South African Journal for Enology and Viticulture, 2011) Lerm, E.; Engelbrecht, L.; Du Toit, M.
    This study focused on characterising 23 Oenococcus oeni and 19 Lactobacillus plantarum strains isolated from the South African wine environment for the development of potential commercial malolactic fermentation (MLF) starter cultures. These strains were characterised with regards to oenological important characteristics, including the genetic screening for enzyme-encoding genes (enzymes that are involved/implicated in wine aroma modification, as well as enzymes pertaining to the wholesomeness of the final wine product), their fermentation capabilities, the ability to maintain viability during MLF, as well as the volatile acidity production. A total of three O. oeni and three L. plantarum strains were selected at the completion of this study. These six strains showed the most potential during the characterisation stages of the study and were able to successfully complete MLF in Pinotage wine. It was also found that L. plantarum strains displayed a more diverse enzyme profile than O. oeni strains, particularly with regards to the presence of the aroma-modifying enzymes β-glucosidase and phenolic acid decarboxylase (PAD), which implies the future use of this species in the modification of the wine aroma profile and use as commercial starter culture.
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    Selection and characterisation of Oenococcus oeni and Lactobacillus plantarum South African wine isolates for use as malolactic fermentation starter cultures
    (South African Society for Enology and Viticulture, 2011) Lerm, E.; Engelbrecht, L.; Du Toit, M.
    This study focused on characterising 23 Oenococcus oeni and 19 Lactobacillus plantarum strains isolated from the South African wine environment for the development of potential commercial malolactic fermentation (MLF) starter cultures. These strains were characterised with regards to oenological important characteristics, including the genetic screening for enzyme-encoding genes (enzymes that are involved/implicated in wine aroma modification, as well as enzymes pertaining to the wholesomeness of the final wine product), their fermentation capabilities, the ability to maintain viability during MLF, as well as the volatile acidity production. A total of three O. oeni and three L. plantarum strains were selected at the completion of this study. These six strains showed the most potential during the characterisation stages of the study and were able to successfully complete MLF in Pinotage wine. It was also found that L. plantarum strains displayed a more diverse enzyme profile than O. oeni strains, particularly with regards to the presence of the aroma-modifying enzymes β-glucosidase and phenolic acid decarboxylase (PAD), which implies the future use of this species in the modification of the wine aroma profile and use as commercial starter culture.