Multiscale structural and rheological features of colloidal low-methoxyl pectin solutions and calcium-induced sol-gel transition.

The multiscale structural and rheological features of a series of dilute and semidilute low-methoxyl (LM) pectin solutions and a representative pectin/calcium sol-gel sample were systematically explored using a comprehensive combination of dynamic (DLS) and static light/X-ray scattering (SALS/SLS/SAXS), rheology, and microscopy (OM/SEM) characterizations. The study focused on the rarely explored colloidal aspect of LM pectin solutions and sol-gel transition, in contrast to the polymeric features extensively explored in previous studies. A highly uniform colloid-like, micron-sized agglomerate species was revealed in dilute solutions, with a progressively increased degree of flocculation in the semidilute regime (≥1.