Removal of starch granule associated proteins affects annealing of normal and waxy maize starches

The effects of starch granule associated proteins (SGAPs) removal on the annealing of waxy and normal maize starch were investigated. Annealing significantly decreased the crystallinity, pasting viscosity, gelatinization temperature range, pseudoplasticity, and thixotropy of waxy and normal maize starches. Annealing little affected digestibility of the starches. Removal of SGAPs reduced the stability of starch granules, but significantly increased pasting viscosity, pseudoplasticity and thixotropy. Both annealing and SGAPs removal decreased the G′ and G″ of normal maize starch in dynamic rheological testing, but had little effect on waxy maize starch. Removal of SGAPs increased rapidly digestible starch (RDS) but reduced resistant starch (RS) for in vitro digestibility. SGAPs removal changed the effect of annealing on starches, and annealing showed different effect on waxy and normal maize starch with SGAPs removal. Annealing increased gelatinization enthalpy and RS of both normal and waxy maize starches after SGAPs removal, and decreased their pasting viscosities and RDS. The rheological properties of starches with SGAPs removal prior to annealing were impacted by amylose content. Annealing decreased pseudoplastic and thixotropy of waxy maize starch with SGAPs removal while increasing dynamic rheological properties of normal maize starch with SGAPs removal.