Aspartic acid (L-Aspartic acid)
Aspartic acid
Japanese: アスパラギン酸（L-アスパラギン酸）
An acidic amino acid contributing to umami. Along with glutamic acid, it is a major amino acid composing the umami of fermented foods.
Aspartic acid is an acidic amino acid contributing to umami alongside glutamic acid. First discovered in asparagus (hence the name), it is also abundant in soy protein.
During miso aging, as proteases break down soy protein, aspartic acid is released along with glutamic acid. While its umami alone is less intense than glutamic acid's, its presence in combination adds depth to the overall flavor.
Also biosynthesized from oxaloacetate, a TCA cycle intermediate, aspartic acid is one of the amino acids linking energy metabolism and taste. The world of umami cannot be told through glutamic acid alone—aspartic acid provides that added depth.