Partial gelatinization treatment affects the structural, gelatinization, and retrogradation characteristics of maize starch-dietary fiber complexes.

Abstract

The effect of partial gelatinization (PG) treatment on the structural, gelatinization, and retrogradation characteristics of maize starch (MS)-dietary fiber (pectin, PE; konjac glucomannan, KG) complex was conducted. The result suggests that PG treatment shows an obvious effect in improving thermal stability, decreasing the viscoelastic, inhibiting starch gelatinization and retrogradation of the MS-PE/KG complex. The decreased breakdown viscosity, storage modulus, apparent viscosity, setback value, and hardness value could confirm these results. Furthermore, PG treatment had a better effect on inhibiting the gelatinization and retrogradation of the MS-0.3 %PE complex than other complexes. This result was proved by reduced setback value (by 78.96 %) and hardness value (by 54.46 % and 44.00 % during cold storage at 1 and 14 days, respectively). 0.3 %PE interacts with starch molecules through hydrogen bonding and electrostatic forces during PG treatment forming a strong starch granule structure to impede starch gelatinization and retrogradation. Moreover, the lighter iodine staining, the obvious coating thin layer, and the thicker fluorescence layer have appeared in the MS-PE/KG complex. The relative crystallinity and the short-range order degree of the MS-PE/KG complex were significantly decreased. The current findings provide the theoretical basis for MS modification to improve the quality and prolong the shelf-life of starch-based foods.