Umami is one of five tastes detectable by humans, along with sweet, salty, bitter and sour. It is the taste quality associated with several amino acids, especially the amino acid L-glutamate, and is described as a ‘hearty, savory’ taste, playing a part in the profile of a number of foods, including meat, fish, vegetables and dairy products.
The researchers, from the Technische Universität München, used a team of trained sensory analysts in conjunction with a fractionation approach to isolate the taste modulators in intensely umami-tasting yeast extracts. They claim to be the first to isolate and identify diastereomers (R)- and (S)-N²-(1-carboxyethyl)guanosine 50’-monophosphate and their formation by a Maillard-type reaction, in which amino acids react with sugars.
The researchers noted that similar techniques have led to the discovery of key taste molecules in red wine, Gouda cheese, dried morel mushrooms and beef broth, among other foods in recent years. They said that although there has been work to boost the yield of known umami compounds in yeast extracts, little was known about the presence of other, undiscovered taste molecules and taste modulating compounds in yeast products.
“Although a series of studies have been performed on the odor-active volatile fraction of yeast extract, knowledge on the taste-active and/or taste-modulating nonvolatiles is rather limited,” they wrote.
The authors said that although yeast extracts are widely used in the food industry “to impart a broth-like, meaty taste impression…to soups, sauces, and snack products”, the yeast extracts available on the market have strong variations in cost and flavor profile.
They tested the taste enhancement properties of the two compounds in conjunction with a monosodium L-glutamate solution, finding that the umami sensation was “slightly sweetish and more full-bodied” with one of the compounds than the other. In order to better understand the different umami taste-enhancing properties of the taste modulators, they called for more precise investigation in future research.
Source: Journal of Agricultural and Food Chemistry
2010, 58, pp.10614–10622, DOI:10.1021/jf102899j
“Discovery of N²-(1-Carboxyethyl)guanosine 50’-Monophosphate as an Umami-Enhancing Maillard-Modified Nucleotide in Yeast Extracts”
Authors: Daniel Festring and Thomas Hoffman