Physicochemical and Structural Properties of Wheat Starch-Chlorogenic Acid Complex under Microwave Irradiation

To investigate the effects of chlorogenic acid on the physicochemical properties and structural characteristics of wheat starch under microwave conditions, microwave treatment was used to analyze the changes in solubility, swelling, freeze-thaw stability, transparency, and sedimentation of chlorogenic acid wheat starch complex. The crystal structure was characterized and the particle morphology was observed. Results showed that adding chlorogenic acid under microwave power of 700 W could increase the solubility of the complex by 3.57 times, increase the expansion, coagulation, and freeze-thaw stability by 34.6%, 14.02%, and 37.88%, respectively, while reducing transparency by 62.97%. X-ray diffraction results showed that the crystalline form of starch changed from the original A type to B+V type, and the crystallinity of the complex decreased significantly with the increase of chlorogenic acid addition. Fourier transform infrared spectroscopy showed that the absorption peak of the complex at 3384 cm−1 was enhanced and widened, and the short range orderliness increased by 40% by adding chlorogenic acid, while the microwave effect could reduce the peak intensity and cause changes in the fingerprint area. It can be seen that chlorogenic acid can effectively affect the structure of wheat starch under microwave conditions, thereby improving its physicochemical properties.