The Impact of Thermal Events on Amylose-Fatty Acid Complexes

The molecular behavior of amylose-lipid complexes was studied using differential scanning calorimetry. rapid viscoanalysis and texture analysis methods. Three amyloses were fractionated, one each from regular, 50% amylose and 70% amylose corn starches. High performance size exclusion chromatography, coupled with multiple angle laser light scattering, was used to determine amylose molecular weight profiles; fractions differed statistically (P>0.05) in their z-average molecular weights (M<INF>z</INF>). Each amylose fraction was complexed with five different fatty acids. After 12 days of storage, amylose-lipid complexes had recrystallization percentages ranging from 42.7 to 98.2%. Cohesiveness (r = -0.84) and adhesiveness (r = -0.75) decreased with increasing M<INF>z</INF> of amyloses (P>0.05). An inverse relationship was obtained between fatty acid chain length and percent recrystallization (r = -0.84, P>0.05). Percent recrystallization decreased when fatty acid chain length increased from C16:0 to C18:0. All complex samples, when adjusted to an equal total starch basis, had decreased viscosities when pasted compared to their native starch or amylose counterparts. Shear thinning of complexes increased with increasing molecular weight (M<INF>z</INF>) of amyloses (r = 0.71, P>0.05). Lower recrystallization rates and decreased viscosity properties could be accomplished complexing by amylose and fatty acids.