Ca2+-induced gelation of low methoxy pectin in the presence of oxidised starch. Part 1. Collapse of network structure

摘要: Abstract The effect of oxidised starch on the networks formed by low-methoxy pectin (2.0 wt%), cooling (from 90 to 5°C) in presence Ca 2+ (10–100% stoichiometric) has been explored rheological measurements under low-amplitude oscillatory shear, and light microscopy. At low concentrations , incorporation increasing (across range 0–30 wt%) causes a progressive increase modulus ( G ′ at 5°C), attributed segregative interactions between two polymers promoting conversion from expanded coil conformation more compact associated form. Incorporation higher concentrations, however, large reductions gel strength, which arise sharp drops during cooling. concentration transition enhancement depletion network strength is independent concentration, increases with degree esterification component DE 31.1–55.8%). Reduction incipient precipitation into aggregates within supporting calcium pectinate network. This interpretation supported microscopy, shows homogeneous distribution grossly heterogeneous structure (length-scale ∼10–50 μm) quantitative analysis moduli reported following paper.