The dynamic changes in physicochemical properties, functionalities, and gel properties of the starch-konjac gum mixture during the melting process: Based on three typical melting temperatures of DSC

Abstract

The present study focuses on investigating the effect of typical melting temperatures (To, Tp, and Tc from DSC) on the dynamic changes of physicochemical properties, functionalities, and gel properties of starch-konjac gum mixture (PS/KGM). The typical melting treatments (HTo, HTp, and HTc) significantly enhanced the PS/KGM synergism, as indicated by the increased thermal stability, and the improved pasting and gel properties. The work suggested that the typical melting effectively stabilized the aqueous mixture system of PS/KGM, showing no phase separation in the water phase system, even after storage for 12 h. The PLM and SEM show that melting at HTo, HTp, and HTc causes partial melting with the loss of birefringence of starch granules, and the granules conglomerate into large clusters with rough surfaces, surrounded by smaller matrices. DSC demonstrated that typical melting significantly raised the To of composite to approximately 77 from 59.10 °C for native. RVA suggested that the melting significantly increased the FV of PS/KGM from 3363 to approximately 8000 mPa s, while the BD decreased from 5009 to approximately 400 mPa·s. Especially in which there is no BD recorded when melted by HTp and HT. The PS/KGM melted by HTo and HTp had more acidic, salty, and shear stability during the thermal process with improved gel texture and freeze-thaw stability than HTc. Partial melting of starch and chain rearrangement is critical for enhancing PS/KGM synergism. As RC% and DM% controlling at approximately 30–35% are the most effective for promoting PS/KGM interaction (HTp > HTo > HTc).