Chemical and Enzymatic Modifications of the Pasting Properties of Legume Starches

Abstract

Abstract Refined legume starches were evaluated for their Brabender Visco/Amylograph properties in their native form and after chemical and enzymatic pretreatment during incubation for 20 h at room temperature. Although exhibiting the characteristic restricted paste viscosities of legume starches, native lentil starch showed much higher viscosity parameters than navy bean starch while field pea starch had very low, stable viscosities. Pretreatments with mineral acids, alkali or enzymes failed to significantly alter the amylographs of the 8% slurries (w/v). Removal of surface lipids on the refined starch granules with propanol/water (3:1 v/v) or chloroform/methanol (2:1 v/v) increased paste viscosities substantially, as did the complexation of the starches with palmitic acid or glyceryl monopalmitate. None of the treatments resulted in complete dissolution of the starch granules and the modified starches showed no improvement in gel syneresis during storage.