Physicochemical, Interactions, and morphology of l-arginine/konjac glucomannan gel: Effects of modified starches

To overcome the drawbacks of dehydration and low gel strength of the gels of l-arginine-treated konjac glucomannan (KGM), thermally irreversible gel was prepared by l-arginine induced KGM-modified starch mixed sol. The effects of the three modified starches (corn modified starch, acetylated bis-starch adipate, and hydroxypropyl distarch phosphate) on the mixed system were investigated by texture analysis, scanning electron microscopy, Low field NMR, Fourier transform infrared spectroscopy and Differential thermal analysis. The results showed a gradual increase in hardness with increasing concentration of modified starch. Differential thermal results indicated that acetylated bis-starch adipate composited gels had the highest thermal decomposition temperature (309 °C). The changes in the textural properties and thermal stability of the three mixed gels were mainly attributed to the enhanced hydrogen bonding between starch/KGM/l-arginine, and changes in the microstructure. When the starch concentration was higher, the denser the gel network structure was, the more difficult it was for water trapped in the gel system to precipitate out. The results indicated that acetylated bis-starch adipate was more suitable to be added to the mixed system to prepare thermally irreversible gels.