Granule integrity and starch solubility during slow, extended pasting of maize starch - the second viscosity peak

Abstract

Maize starch granule integrity and starch solubilisation at specific intervals during a relatively long pasting profile-which is known to exhibit biphasic peak viscosity character-was studied by microscopy and high-performance size-exclusion chromatography, respectively. Maize starch granules, although swelling and leaching components, remained mainly intact until the second viscosity peak when they lost integrity and formed a relatively homogenous paste. The second viscosity peak coincided with a decrease in starch content in solution and amylose going out of solution was mainly responsible for this decrease. It is suggested that the loss of granule integrity during the second viscosity peak increases the potential for amylose to form complexes with lipids at this stage. It is further suggested that the second viscosity peak is due to the formation and breakdown of superstructures of amylose-lipid complexes.