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Download fileProduction of an in Vitro Low-Digestible Starch via Hydrothermal Treatment of Amylosucrase-Modified Normal and Waxy Rice Starches and Its Structural Properties
journal contribution
posted on 2016-05-26, 00:00 authored by Ji Hyung Kim, Ha Ram Kim, Seung
Jun Choi, Cheon-Seok Park, Tae Wha MoonWe
investigated dual modification of normal and waxy rice starch,
focusing on digestibility. Amylosucrase (AS) was applied to maximize
the slowly digestible and resistant starch fractions. AS-modified
starches were adjusted to 25–40% moisture levels and heated
at 100 °C for 40 min. AS-modified starches exhibited a B-type
crystalline structure, and hydrothermal treatment (HTT) significantly
(p < 0.05) increased the relative crystallinity
with moisture level. The thermal transition properties of modified
starches were also affected by the moisture level. The contents of
rapidly digestible starch fraction in AS-modified normal and waxy
starches (43.3 ± 3.9 and 18.1 ± 0.6%) decreased to 13.0
± 1.0 and 0.3 ± 0.3% after HTT, accordingly increasing the
low digestible fractions. Although the strengthened crystalline structures
of AS-modified starches by HTT were not stable enough to maintain
their rigidity under cooking, application of AS and HTT was more effective
in waxy rice starch than normal rice starch when lowering digestibility.