12,587
edits
Yeast: Difference between revisions
no edit summary
No edit summary |
No edit summary |
||
| Line 279: | Line 279: | ||
The major stresses encountered by industrial yeasts are temperature shock, osmotic stress and ethanol toxicity.<ref name=walden/> | The major stresses encountered by industrial yeasts are temperature shock, osmotic stress and ethanol toxicity.<ref name=walden/> | ||
In the brewing industry, the viability and vitality of pitching yeast are crucially important for continued successful beer-making. Yeast management before, during, and after fermentation should endeavor to minimize physiological stresses imparted on brewing yeast cultures (21,27). Stress may be imposed on brewing yeast at pre-fermentation (e.g., acid-washing, cold-shock, oxidative stress, and nutrient starvation); primary and secondary fermentation (e.g., osmostress, ethanol toxicity, pH/temperature fluctuations, and CO2/hydrostatic pressure); and post-fermentation (e.g., mechanical shear, cold-shock, and nutrient starvation). Several bioprocessrelated approaches have been advocated to maximize brewing yeast viability and vitality at different stages of yeast handling (13,31). These include nutrient-controlled yeast propagation by fed-batch cultivation, selective yeast cropping from cylindroconical fermenters, and strict control over yeast storage and acid-washing conditions.<ref>Walker GM. [https://www.tandfonline.com/doi/abs/10.1094/ASBCJ-56-0109 Magnesium as a stress-protectant for industrial strains of Saccharomyces cerevisiae.] ''J Am Soc Brew Chem.'' 1998;56(3):109–113.</ref> | |||