关键词:
Differential scanning calorimetry
摘要:
Four maize genotypes (common, waxy, ne du, and ne su2) were examined by differential scanning calorimetry (DSC) in the presence of four surfactants (sodium dodecyl sulfate [SDS], dodecyltrimethylammonium bromide [DOTAB], sodium hexadecyl sulfate [SHS], 1-monolawoyl-rac-glycerol [ML]) to characterize the starch-lipid complexes produced and provide evidence of differences in starch structure. The ionic surfactants with a C-12 hydrocarbon tail reduced the gelatinization onset temperature, a phenomenon that does not occur typically with neutral surfactants or with surfactants with longer hydrocarbon tails. Subtracting the DSC curves, the exotherm we suspected was caused by starch-lipid complexation, which occurs concomitantly with the gelatinization endotherm, was identified and provided evidence of the existence of amylopectin-lipid interactions. Apparent starch amylose content correlated well with enthalpies of amylose-lipid complexes. Complexes formed from DOTAB produced DSC endotherms that were broad and shallow and that shifted to lower temperatures as the DOTAB concentration increased. This was in contrast to other surfactants that normally produce amylose-lipid complex endotherms at temperatures independent of surfactant concentration.