Aqueous pigmented coating formulations for improving opacity and processes for their manufacture are disclosed. Specifically, the aqueous pigmented coating formulations comprise an acylated lecithin that comprises a chemically modified lecithin and less than 10% (by total weight acylated lecithin) free fatty acid. Additionally, the acylated lecithin is substantially free of fatty acid esters and surfactants. The acylated lecithin provides an increase in opacity to paper and paperboard coated with the aqueous pigmented coating formulation.