Abstract
Four important attributes (complexing ability, solubility, viscosity and gelling property) of partially debranched waxy rice starches (PDRSs) with different degrees of debranching (PDRS1–4) were investigated. The average chain lengths of PDRS1–4 were 87.2, 44.4, 30.2 and 21.4, respectively. All PDRSs had significantly lower viscosity and higher solubility than those of native starch. The retrogradation of PDRSs, as indicated by solubility values and gel appearances, increased with an increase of the degree of hydrolysis (DH). The gel characteristics of each PDRS were unique and varied with the DH, concentration, and storage temperature. At low temperature (4 °C), PDRS3 and PDRS4 at concentrations ≥ 5% formed easily spreadable opaque firm gels, while only PDRS4 produced a firm gel at 30 °C. Turbid solutions or solutions with small aggregates were observed for all PDRSs at 1% concentration. The complexing abilities of PDRSs with iodine increased when increasing the DH, and all PDRSs exhibited significantly higher complexing ability than native starch.
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