Saccharomyces cerevisiae mannoproteins that protect wine from protein haze: Evaluation of extraction methods and immunolocalization

Yeast-derived haze-protective mannoprotein material (HPM) offers protection to white wines from commercially unacceptable turbidities. HPM extraction methods have been evaluated using three winemaking strains of Saccharomyces cerevisiae. Digestion with Zymolyase of cells pretreated with DTE and EDTA gave the greatest yields of active material. Heat treatment of cells with SDS also released active material but the quantities were low. Treatment of the cells in an autoclave or with a French pressure device was less effect ive. A detailed study was conducted on the strain Maurivin PDM. SDS was not necessary to extract HPM from PDM; boiling the cells for 5 min in Tris buf fer was sufficient. HPM could also be extracted with EDTA during the pretre atment of the cells prior to Zymolyase digestion. The data suggest that HPM was noncovalently linked to other cell wall. components and loosely associ ated with the cell wall. An immunological investigation showed that a speci fic mannoprotein with haze-protective activity, HPF1, was located primarily on the outermost; and innermost layers of the cell wall.