What are Yeast Extracts?
Yeast extract is the general term to refer to various varieties of processed yeast that is formed by extracting the contents of yeast cells. The disintegration of the yeast cells renders the yeast inactive – i.e. the yeast can no longer be used for its traditional purpose (for example fermentation or as a leavening agent). These yeast extracts are instead commonly used as flavour enhancers, creating typically savoury, meaty, umami and salty taste sensations.
Yeast Extracts VS MSG
A common misconception is that yeast extracts are synonymous with MSG (monosodium glutamate) – a sodium salt of glutamic acid, which some individuals are sensitive to. Autolyzed yeast extracts have a savoury and meaty flavour, which can be attributed to its content of glutamic acid, peptides, nucleotides amino acids, among other componenets. Glutamic acid is a naturally occurring amino acid responsible for this savoury or “umami” flavour sensation. MSG also provides this umami taste sensation and MSG is formed when free glutamic acid (i.e. glutamic acid not attached to protein) attaches with sodium. Therefore, MSG formation is possible in foods where free glutamic acid is present.
Although autolyzed yeast extracts often contain glutamic acid it is important to emphasize that glutamic acid is by far not exclusive to yeast extracts. Glutamic acid is found in the vast majority of foods, most notably those that contain a high level of protein (both vegetable and animal derived protein).
