There have been several patents that involve the
addition of crude protein hydrolysates. Apart from
their role as amino acid precursors, they may also
act as a source of reducing sugars or other carbonyl
compounds thereby serving as reactants for the
Maillard reaction. The best known protein
hydrolysates universally accepted for their useful
function for flavor are HVP and yeast extract. Several
early patents have made use of yeast extracts or yeast
hydrolysates as one of the reactants for the thermal
generation of meat flavorings.