Yeast: composition, properties, uses and species
By its chemical composition yeast is enoughThey are unstable: in the majority of them it depends on their kind. At the moment there are already about one and a half thousand species. Also, the composition is highly dependent on the medium in which the yeast is multiplied. Most often they contain a quarter of dry matter and tricheverty water. The dry matter includes such components as carbohydrates, inorganic substances, nitrogen, fats and proteins.
Inorganic substances are usually representedPotassium and phosphoric acid. In the carbohydrate part of yeast, polysaccharides are contained, and in proteins, amino acids, which include all the necessary organisms; In the fat can be found polyunsaturated and saturated fatty acids.
Varieties of yeast
Varieties of yeast have learned to distinguish at the end of the nineteenth and early twentieth centuries: the scientists conducted many experiments and many works on this topic have been written.
Among the main types of yeast, which are used today in various industries, you can name such as pressed, baking, dry active, beer, instant, wine.
The easiest way to find baker's yeast isAre sold in any product store, put up in small bags; They have a sufficiently long shelf life and are easy to use - even a child can cook them on their basis.
Pressed yeast is also known asConfectionery. They are much more complicated in storage: if stored outside the refrigerator, then after two weeks they will not be usable, and if the ambient temperature is about thirty degrees, the shelf life is reduced to three to four days. It is recommended to store them in the freezer, Will be enough to preserve their properties for two months. Before using yeast confectionery must be diluted with warm water.
Dry yeast is notable for a long shelf life,If their packaging has not been opened: in a cool dry place they can lie about two years. Open yeast requires storage in a tight closed container placed in the refrigerator - so they can be stored for about four months.
Dry active yeast must be dissolved in warm water (four parts of water one part of the yeast), leave for ten minutes, then stir and wait a little more.
Instantly dissolving yeast have almost the same properties and they are used approximately the same way, but they are ready for use after ten minutes in warm water.
All the aforementioned varieties of yeast cankeep their activity for a longer time if subjected to freezing, but do not do it abruptly - they are sensitive to temperature changes that destroy yeast cells, so that they should be thawed gradually, and the water to dissolve them needs to be slightly warmed up.
Brewer's yeast is different from those thatare used for the test, and there are a lot of them. It is for this reason that different beers have different colors, taste and other characteristics. For example, El is made with special yeast, which are less susceptible to alcohol than other species. As a rule, brewer's yeast exists as a liquid, for this reason, before use, do not require dissolution.
Also, yeast is used for cooking kvass, however, in this case, lactobacilli also participate in the process.
Yeasts that are used to createvarious wines of ishampan, have a high fitness for existence in a medium with a high content of alcohols and a high temperature at which other yeasts normally die.
There are other varieties of yeast that are notThey are used for baking - they are dietary or food yeast: they go through heat treatment and go into a state of inactive, but their cells remain intact, which helps preserve vitamins, proteins and other useful substances. In such a lot of vitamins, and you can buy them in the departments of healthy nutrition and pharmacies.
Use of yeast
Different types of yeast are used today indifferent branches: vkvasovarenii and brewing, industry - most of all in bakery, winemaking, the production of certain dairy products, medicine (as a preventive and therapeutic agent), cooking.
Yeast contains many vitamins and fullproteins, therefore, theoretically, they can be added to various dishes, and experiments in this direction were carried out in the first third of the twentieth century, but this practice did not receive wide dissemination. There is an opinion that yeast can be added to green, fresh and sour cabbage soup, rassolniki, borsch, white iluk sauces.
Therapeutic qualities of yeast
Natural baker's and brewer's yeast canused as a remedy; also with their use, special drugs such as hephephytin, which is prescribed to patients with nervous system disorders, skin problems, hypovitaminosis and metabolic disorders, can be made with their use.
In the liquid state yeast can be prescribeda specialist in medicine to use inward to increase the absorption of various nutritional substances, improve the work of the stomach, intestines and pancreas, increase the immunity of the organism to various diseases that can be caused by viruses and bacteria. And liquid yeast in this respect is much more useful than dry yeast. Also yeast can be prescribed for gastritis, enterocolitis, recovery from severe diseases. To be treated independently by the use of yeast is strictly forbidden - the doctor should prescribe the treatment.