The phosphorus content of the flours was determined by the phosphovanado-molybdate (yellow) method (AOAC, 2005). The other elemental concentrations were determined, after wet digestion of sample
ash with a mixture of nitric and perchloric acids (1:1 v/v), using Atomic Absorption Spectrophotometer (AAS, Buck Model 20A, Buck Scientific, East Norwalk, CT06855, USA)