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36 WINES&VINES July 2016 WINEMAKING PRACTICAL WINERY & VINEYARD bolic activity is possible if the barrier between the cytoplasm and the surrounding media is not intact. 13 One protein associated with the cell membrane (Lo18) has been extensively studied. It is involved in stress response by maintaining membrane integrity through in- teractions with phospholipids. 10 Other cytosolic stress proteins also have been studied, and the results have provided direction for further research. Along with the choice of the proper selected wine LAB strain to use, timing the addition of an MLF starter culture is crucial. Commercial wine LAB starter cultures can be adapted to wine by inoculating them into the acidic but low-alcohol must at the start of (or 24 to 48 hours into) alcoholic fermentation. The term "co-inoculation" is used to describe this pro- cess, but the yeast and bacteria are rarely added at the same time. Selected wine LAB develop in the ferment- ing must, where they reactivate tolerance mechanisms that facilitate their growth in wine. Numerous wine producers have tried and adopted this practice as the time required to completely degrade L-malic acid is greatly reduced compared to sequential inoculation, which is the addition of selected wine LAB after alcoholic fermentation has completed. Co-inoculation is particularly interesting for low-pH wines, as shown by Caroline Knoll et al. 19 The study showed that in a Riesling must with a pH of 3.1, L-malic acid was de- graded from 25 to 50 days sooner with co- inoculation than it was when using sequential inoculation, and fruity aroma esters were more abundant. The sensory impact of co-inoculation also has been demonstrated in other trials—espe- cially with Merlot, where it significantly influ- ences the aroma profile. Generally, the fruity and lactic characters are affected the most. The fruity notes can be boosted either by an in- crease in ester concentration or by a decrease in lactic notes. Lactic notes are decreased ei- ther because esters are degraded, or because a lactic and smoky mask has developed. 2 Co-inoculation modifies the wine's aroma profile, but it seems difficult to specify a gen- eral trend for the following reasons: First, the wine LAB malolactic enzyme activities respon- sible are linked to overall bacterial metabo- lism, which is influenced by interactions with the yeast and population ratio; second, sub- strates available to wine LAB depend on the simultaneous influence of yeast and bacteria on final wine composition, notably for the taste and aroma. Genomics, a new approach Molecular biology made its appearance in enology in the early 1990s. Subsequent ad- vances in equipment and methodology have permitted research that previously was not possible. The first application of genetic tech- niques to enology was the precise and reliable typing of yeast and bacteria strains. The meth- odology initially used probed hybridization and the genetic profiles of entire or hydrolyzed genomic DNA obtained by a variety of electro- phoretic techniques. Until the advent of newer genetic tech- niques, it was extremely difficult to distin- g u i s h o n e m i c r o b i o l o g i c a l s t r a i n f r o m another of the same species, unless it had info@vintegrate.com 800 • 487 • 3363 vintegrate.com Winery Software M ake • M anage • Sell The early 2000s marked a turning point in the study of Oenococcus oeni, as sequencing of the entire genome became possible.