Posted on 07 Mar 2015 21:05
Autolyzed yeast extract, is a food ingredient or additive that comes as a liquid, paste, powder, or in a granular state. It is used as a flavoring agent or enhancer, and as a firming agent. It comes from yeast that has been specially treated.
How Autolyzed Yeast Extract is Made
Autolyzed yeast is produced by the allowing the peptide bonds of the proteins in the yeast to hydrolyze. This is done by one of two different methods. Edible yeast (cells) are heated under tightly controlled conditions to a temperature that causes proteolytic enzymes already present in the yeast to "digest" the proteins, and break their bonds, producing different peptides and amino acids. During this process, destruction of the cell walls occur. Brewer's yeast or baker's yeast may be used for this process. A yeast "cream" is slowly heated to 55° C. and afterwards is pasteurized at 70° C to deactivate the enzymes and to kill any living cells.
In another method, the yeast may be enymatically hydrolyzed by adding exogenous proteolytic enzymes that are allowed to be used in this process (ones considered GRAS or regulated food additives). Acid treatment is also used, where the proteins are broken down by acid rather than enzymes. Afterwards the acid is neutralized and the results are filtered and concentrated.
The simpler amino acids that are left from the process can enhance the taste of certain foods. However, this autolyzed yeast still contains the insoluble components of the destroyed cell walls. This can be used itself as a flavor enhancer or as an ingredient to make other processed flavors, if clarity is not important to the resultant ingredient.
Autolyzed yeast extract is made by separating the the cell components from the amino acid components. This is done by centrifugation or other means, and a the resultant yeast extract id then filtered and spray-dried, or left as a liquid. It can help give a "meaty" flavor to foods. Unlike the pre-separated autolyzed yeast, this extract is more clear and able to be used in a wider variety of situations.
The separated insoluble cell-wall components are separately dried and can be used for animal fodder.
Yeast extract, also called Baker's yeast extract, without the word autolyzed, is a similar product which also is a mixture of amino acids and peptides, carbohydrates, in which the cell walls of the yeast have been ruptured and separated from the proteins.
Autolyzed Yeast Extract and MSG
Autolyzed yeast extract, like yeast extract, soy extracts, and hydrolyzed vegetable protein, contains naturally occuring MSG (monosodium glutamate). Food alarmist have often reported this ingredient as a "hidden source of MSG in foods." Foods using autolyzed yeast extract cannot claim to be MSG free with labelling such as "NO MSG" or No added MSG." MSG, as the sodium salt of glutamic acid, when it is used directly in foods, must be listed as such, but it does not have to be listed when it occurs in ingredients like autolyzed yeast extract. Many people have reported adverse reactions to MSG, but there has been little clinical evidence linked to such reactions.
Uses in Foods
Although autolyzed yeast extract can contribute its own flavor to a food, it is primarily considered a flavor enhancer, used to enhance flavors already present in food, much like salt, although it has a taste of its own, brings out or pronounces desirable flavors in food. As well, it can provide aroma. It can also assist in Maillard Reactions during cooking.
The ingredient is used in many processed foods, except for baby foods or infant formulas. It also has nutrient value, rich in protein and Vitamin B. In fact, they are used as nutritional supplements in feed and in industrial fermentation operations.