The synergistic effect of hydroxypropyl methylcellulose and κ-carrageenan or pectin on anti-freezing

Ten polysaccharides were mixed to select polysaccharides with the synergistic anti-freezing effect in this study. It was found that hydroxypropyl methylcellulose (HPMC) and pectin (PEC) or κ-carrageenan (κ-CAR) synergistically decreased the freezing temperature of water and enhanced the ice recrystallization inhibition activity. Moreover, HPMC/κ-CAR exhibited greater synergy than HPMC/PEC. Raman spectroscopy analysis demonstrated that these polysaccharides increased the disorder of water molecules and inhibited the transition from liquid water to solid ice, and HPMC and PEC or κ-CAR had a synergistic effect on increasing the disorder of water molecules. Particularly, dynamic ice-shaping measurements showed that the HPMC/κ-CAR mixture changed circular ice into hexagonal ice in 20.0 % sucrose solution, whereas the HPMC/PEC mixture did not. Moreover, κ-CAR was more compatible with HPMC than PEC. The above differences might explain why κ-CAR was more effective than PEC in improving the anti-freezing ability of HPMC.