Synergistic Effect of Charged Amino Acid Combined with Dry Heating Treatment on Physicochemical Properties and In Vitro Digestibility of Cornstarch

Abstract

To improve processability and nutritional properties, normal cornstarch is modified by dry heating treatment (DHT) at different heating temperatures (70, 100, and 130 °C) for different heating times (0, 2, 12, 48 h) after mixing with various amino acid types (aspartic acid and lysine). The combination treatment effectively retards the starch digestibility. Among all samples, the rapidly digestible starch content of lysine–cornstarch mixture after being heated at 130 °C for 12 h is the lowest (14.1%), which decreases by 13% as compared to cornstarch. The gelatinization temperatures, gelatinization enthalpy, and relative crystallization of the combination treated cornstarch increases while no significant changes are observed in the X‐ray diffraction and Fourier transform infrared spectroscopy of those starches. With increasing DHT temperature or prolonged DHT time, the viscosity of the heated aspartic acid–cornstarch mixture decreases, while that of the heated lysine–cornstarch mixture increases. Cluster analysis indicates that there are obvious differences between the samples with added aspartic acid and adding lysine. The combination treatment at 130 °C shows a more significant effect on the properties of AA‐CS.