title: Changes in wine yeast storage carbohydrate levels during preadaptation, rehydration and low temperature fermentations.
abstract: The metabolism of glycogen and trehalose was analysed in a wine yeast strain fermenting at 25 and 13 degrees C. Trehalose and glycogen degradation were completed during the lag phase of fermentation. Ammonia was taken up rapidly and once it had been reduced to negligible amounts, the synthesis of trehalose started. Glycogen followed a similar pattern. If trehalose synthesis was taken as a stress indicator, the fermentation at 13 degrees C could not be considered stressful because the maximum concentrations are similar at both temperatures. In industrial fermentations, and after a preadaptation in grape must for several hours at 18 degrees C, the lag phase was reduced significantly, and this may be why trehalose and glycogen were completely depleted at the beginning of the low temperature fermentation. Various preadaptation conditions were tested so that their influence on trehalose and glycogen degradation could be determined. The presence of fermentable carbon sources, such as glucose or fructose, triggered the mobilisation and use of trehalose. However, just increasing the osmotic pressure did not reduce the trehalose content. No such differences were observed in glycogen metabolism.
authors.affiliation: Unitat d'Enologia del Centre de Referència en Tecnologia dels Aliments, Dept Bioquímica i Biotecnologia, Facultat d'Enologia de Tarragona, Universitat Rovira i Virgili, Ramon y Cajal 70, Tarragona 43005, Spain.
authors.forename: Maria Teresa
authors.initials: MT
authors.lastname: Novo
authors.forename: Gemma
authors.initials: G
authors.lastname: Beltran
authors.forename: María Jesús
authors.initials: MJ
authors.lastname: Torija
authors.forename: Montserrat
authors.initials: M
authors.lastname: Poblet
authors.forename: Nicolas
authors.initials: N
authors.lastname: Rozès
authors.forename: José Manuel
authors.initials: JM
authors.lastname: Guillamón
authors.forename: Alberto
authors.initials: A
authors.lastname: Mas
mesh_terms: D005285:Fermentation; D005516:Food Microbiology; D006003:Glycogen / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000254:growth & development* / Q000378:metabolism*; D013696:Temperature; D014199:Trehalose / Q000378:metabolism*; D014867:Water / Q000378:metabolism; D014920:Wine / Q000382:microbiology*
chemical_list: D014867:Water; D006003:Glycogen; D014199:Trehalose