Carboxy groups in fatty acids facilitate the formation and thermal stability of starch-fatty acids complexes

This study aimed to investigate the effect of the number of carboxy group on the formation of complexes between starch and fatty acids using different dicarboxylic acids and monobasic acids as ligand. The complexing index (CI) indicated that dicarboxylic acids could form complexes with starch and show stronger complexing ability than corresponding monobasic acids. Results from differential scanning calorimetry also displayed that starch-dicarboxylic acids complexes presented higher onset temperature, narrow transition peaks and higher enthalpy change, indicating the higher thermal stability and uniform and homogenous crystal of starch-dicarboxylic acids complexes. X-ray diffraction, Fourier transform infrared and Raman spectroscopy showed that the long-range and short-range order of starch-dicarboxylic acids complexes was better than that of starch-monobasic acids. According to above results, fatty acid with two carboxyl groups could form larger amount and more stability complexes than it is with one carboxyl group.

Automated summary

The study found that complexes formed between dicarboxylic acids and starch have higher thermal stability and more uniform crystal structure compared to those formed with monobasic acids. Additionally, the long-range and short-range order of the complexes between dicarboxylic acids and starch is better than those between monobasic acids and starch.