Yeast extracts consist of yeast cell contents without cell walls; they are used as food additives or seasonings, or as nutrients for bacterial culture media. They are commonly used to create salty and umami flavors, and can be found in a wide variety of packaged foods, including frozen foods, biscuits, snack foods, gravies, stocks, etc. They are rich in vitamin B (but do not contain B12), so they are especially important for vegans and vegetarians. Yeast extracts and fermented foods contain glutamic acid (free glutamic acid), an amino acid that increases umami taste. Glutamate is found in meat, cheese, fungi (mushrooms) and vegetables (such as broccoli and tomatoes).
Production of yeast extract
Yeast extract is made from natural baker's yeast or brewer's yeast. In the early advanced civilization, fresh yeast has been an important part of food culture. It is not only used for toasting, but also for brewing beer and wine.
Yeast extract is obtained from fresh yeast in 5 steps. Enzymes break down the proteins present in yeast cells into smaller components, and dissolve the surrounding cell walls, allowing the contents to leave the cell. Removal of cell wall residues by separation. Therefore, yeast extract is composed of proteins, amino acids, carbohydrates, vitamins and minerals from yeast cells, without surrounding cell walls.
Baker's yeast and brewer's yeast are living organisms belonging to the family of fungi. We use their properties, such as when baking, when we add sugar to the dough and let it ferment in a warm place.
The first step in the production of yeast extract, namely fermentation, follows the same principle: adding sugar to nourish the yeast. In addition, a temperature of 30 degrees Celsius and sufficient oxygen are supplied to a large container, a so-called fermenter, so that the yeast can grow in an optimal way. Thereafter, the yeast is concentrated and washed in a centrifuge to remove residual sugar. The result is a sticky creamy yeast mass.
Then put the yeast in a large tank with a temperature of 45-55 degrees Celsius. Yeast stops growing at about 40 degrees Celsius, and enzymes break down the proteins and other large molecules in the yeast into smaller molecules. The cell walls of yeast cells are also partially broken down. This means that smaller molecules can now leave the yeast cells and mix with the aqueous solution in the tank.
A variety of factors can be used to control the process. For example, the time and temperature of the yeast in the tank play an important role and have a significant impact on the future taste of the corresponding yeast extract. The product produced by this process is a liquid that tastes like broth, but in fact has amino acid characteristics very similar to cooked broth.
In order to produce the final yeast extract, the liquid must now be centrifuged to remove the yeast cell walls. Valuable proteins, amino acids, vitamins and minerals from yeast cells remain in the yeast extract. Simply put, yeast extract contains all the natural components of yeast cells without surrounding cell walls.
Finally, the yeast extract is concentrated into a paste or liquid in a gentle evaporation process at about 60 degrees Celsius, or all water is evaporated through a spray drying process. The final product is then ready to be shipped to the food manufacturer that uses the ingredients to flavor the product.