2.6. Morphological assessment of yeasts in contact with polyphenols
The strain biomass grown in the media used for mat and invasive growth assays was microscopically observed (Zeiss Standard 20 op-tical microscope) to assess the in fluence of the experimental condi-tions on cell morphology. The yeast cell morphology was also observed after growth in grape must. Here, 600 μL ofexponential phase culture were inoculated in 12 mL tubes containing must of the cultivar Cabernet, obtained from Malaspina winery (MelitoPorto Salvo, RC, Italy). The must was heated to remove appreciable growth of wild microorganisms. The micro-fermentations were stat-ically incubated at 25 °C and observed under the microscope after 3,8, 25, and 40 days. At each stage, the cells showing unusual mor-phology such as short chains of cells and/or cells arranged in clusters were counted and expressed as a percentage of the total cells with singular elliptic morphology.