Dorothy FarrarYeast (yeasts)
Yeasts are single-celled fungi that convert sugars into alcohol and carbon dioxide in the fermentation process. Thousands of years ago, people used the yeast fungi in sourdough to produce an important foodstuff, bread. Microscopically small fungi live in the sourdough, whose activity promotes the “rising” of the dough and the loosening of the bread. Viewed under the microscope, baker’s yeast provides evidence that it consists of oval or spherical single cells, the yeast fungi.
Construction and lifestyle
Yeast fungi have rounded structures and do not form a mycelium (underground thread network). The cells consist of the cytoplasm, the cell nucleus, the cell membrane and the cell wall, which has embedded chitin. Like all other fungi, the cells of the yeast fungi have no chloroplasts and therefore no chlorophyll either. Yeast fungi are unicellular organisms. Above all, they prefer moist or liquid habitats, among other things they are also found in plant saps and animal tissues.
Reproduction
Yeast reproduces asexually by cell division (budding). During the process, a bulge forms on the mother cell after the nucleus has divided. This grows into a bud that contains one of the two cell nuclei and rapidly increases in size. The newly created daughter cell can separate from the mother cell or remain connected to it. As a result of many subsequent division steps, a large cell structure can arise. With optimal living conditions, sufficient nutrition in the form of sugar, moisture and warm temperatures, the cells divide extremely quickly, several thousand times within 24 hours.
Nourishment
Their diet is heterotrophic, just like other fungi. They absorb organic energy-rich substances. This is primarily sugar, which they extract from fruit or other sugary foods. In nature, yeast fungi can be found on all types of fruit anyway. In addition to sugar, they also need oxygen and heat for optimal growth and rapid reproduction.
The cells of the yeast fungi contain enzymes that split glucose, for example. Under the influence of oxygen, yeast cells completely break down sugar into carbon dioxide and water. With oxygen deprivation, the degradation process is different. In this case, the sugar is incompletely broken down into alcohol (ethanol) and carbon dioxide. This is an alcoholic fermentation process, since it all takes place without oxygen (anaerobic).
Fermentation
Yeast fungi play an important role in all fermentation processes. Fermentation is a form of dissimilation. In this process, the body’s own organic high-energy compounds are broken down into low-energy substances under the influence of enzymes from the microorganisms, mostly in the absence of oxygen. This releases energy that the organisms need to maintain their vital functions.
Yeast fungi for wine making
The yeast fungi are involved in the production of wine. Over the course of several weeks, they convert the stored sugars in the fruit into alcohol, more precisely wine. Provided that the fermentation process takes place without oxygen. Otherwise, at the end of the process, instead of the preferred wine, vinegar will be produced, which also has a nutritional value, but is undesirable in this case. The wine production takes place in glass containers, the wine balloons. These are equipped with a fermentation tube to allow a by-product, carbon dioxide, to escape easily. This tube is designed in such a way that the gas escapes, but air cannot flow in.
Various types of fruit are suitable for wine production, eg cherries, apples, grapes, currants and various forest fruits. Special beer yeasts are also used in beer production. First and foremost, they influence the aroma and alcohol content of the respective beer in the alcoholic fermentation process.
Yeast fungi in baking (baker’s yeast)
The production of baker’s yeast takes place using sugar beet residues as a natural food source for the yeast fungi. These small organisms can thus be multiplied within a very short time without great financial expense in order to process them for the food industry in the production of baked goods. Yeast fungi are active when baking bread. The decomposition product that is released as a result of their vital activity – carbon dioxide – causes the dough to puff up as a gas and is therefore responsible for the fluffiness of the bread. Other decomposition products such as water or alcohol evaporate due to the heat in the baking process.
More meaning
Very large amounts of nutritious feed are also needed to feed the extensive livestock population. Biotechnological processes using yeast fungi make it possible to produce high-quality feed from waste materials at low cost.
Certain yeast fungi are ideal for improving the quality of toxic but still nutrient-rich waste water that is produced during the production of wood pulp. These fungi find a lot of food and moisture in the sewage, and at optimal temperatures their reproduction rate increases exponentially.
This produces valuable fodder yeast, which is fed to livestock in pressed form as pellets. This shows an enormous economic benefit, the waste water treatment relieves the environment and the production method of animal feed is very cost-effective.
Feed yeasts are also obtained from residues that occur in the production process in quark production (whey), sugar production (molasses) and oil processing. The demand for alcohol for technical purposes is increasing and is also covered by fermentation processes.
Starch from potatoes and grain, even from sawdust and sawdust, is also saccharified and fermented to alcohol by yeast. However, this methyl alcohol (methanol) is very toxic and can lead to blindness if consumed. Its use is limited to the production of methylated spirits, antifreeze, medicines and cosmetics.
Hello and welcome to my Health Guide & Encyclopedia! My name is Dorothy Farrar, and I'm the founder and main author of this platform.
My passion for health and wellness started at a young age when I became interested in the connection between the food we eat and the way we feel. This fascination led me to study nutrition and dietetics in college, where I learned about the importance of a balanced diet and the impact of various nutrients on the body.