Effects of Cooking Treatments under Different Pressures on the Structure and Physicochemical Properties of Chickpea Starch

In this study, chickpea starch was treated with atmospheric pressure steaming, atmospheric pressure boiling, high pressure steaming or high pressure boiling for 20 min. The effects of the four common heat treatment methods on the ordered crystal structure, particle structure and physicochemical properties of chickpea starch were investigated through the determination of physicochemical parameters, X-ray diffraction spectroscopy, infrared spectroscopy and microstructure observation. Results showed that the granular structure of chickpea starch was completely preserved after steaming treatment. It exhibited birefringence under polarized light and its crystal structure was still type C_A. After boiling at atmospheric and high pressure, the relative crystallinity decreased from 31.4% to 25.5% and 20.4%, respectively. Moreover, the peak viscosity, though viscosity, final viscosity, breakdown value and setback value decreased. The degree of retrogradation of chickpea starch after heat treatments was as follows in decreasing order: high pressure steaming > atmospheric pressure steaming > native starch. The granular structure and crystal structure of chickpea starch were damaged seriously after boiling treatment. The relative crystallinity was 5.9% and 3.6% after boiling at atmospheric and high pressure, respectively, and the viscosity decreased. The treatment starch showed no obvious retrogradation after gelatinization. In addition, the crystal structure of chickpea starch was damaged more seriously after high pressure treatment, while there was no significant difference in granular morphology, birefringence or functional groups between the samples treated by atmospheric and high pressure. The results of this research can provide a theoretical basis and guidance for the development and utilization of chickpea starch and are of significance for enriching the basic theory of chickpea starch.