Five gelatinized jackfruit starches (GJFSS: M1', M5', M6', M11', and BD') were prepared using amylose mixed with five types of amylopectin. M1' had the lowest degree of polymerization while BD' had the highest. The five GJFSS samples showed significant variations in microstructures, varying from a compact structure (M1') to a loose structure (BD'). The freeze-thaw stability was consistent with results of the microstructure. High syneresis formed compact structure (M1'), and low syneresis formed a loose structure (BD'). As the degree of polymerization of amylopectin increased, the gelatinization enthalpy, peak viscosity, breakdown, final viscosity, setback, and absorbance ratio decreased, while the transition temperature and pasting temperature increased. The thermal, pasting properties, and the short-range molecular order, were consistent with the results of the microstructure and syneresis. All the results indicated that the degree of polymerization of amylopectin is an important structural factor that can significantly affect the gelatinization properties of starch.
Keywords: Amylopectin; Degree of polymerization; Gelatinization properties; Jackfruit starch.
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