It is a salt or ester of pyruvic acid. Here is an image of what it is...
And these
Formula: C3H4O3
Molar mass: 88.06 g/mol
IUPAC ID: 2-oxopropanoic acid
Density: 1.25 g/cm³
Related keto-acids, carboxylic acids: acetic acid; glyoxylic acid; oxalic acid; propionic acid; acetoacetic acidAcidity (pKa): 2.50