Doctor of Philosophy / Department of Grain Science and Industry / Yong Cheng Shi / The reaction of starch and octenylsuccinic anhydride (OSA) produces lipophilic starch
that has the ability to stabilize oil-in-water emulsions. The functional properties of
octenylsuccinate (OS) starch depend on its molecular structure and distribution of OS groups.
Structures of OSA and OS starches were investigated by NMR spectroscopy. In granular OS
starches, OS groups were substituted at O-2, O-3 positions, but not the O-6 position. Distribution
of OS groups was investigated by enzyme hydrolysis followed by chromatography analysis. OS
substitution predominantly occurred at the amorphous region of the starch granules. OS starch of
degree of substitution (DS) 0.018 had OS groups located close to the branching points, whereas
the OS substitution in OS starch of DS 0.092 occurred near non-reducing ends as well as the
branching points. OS starches with different substitution patterns were prepared from two
approaches. OS starches from the first approach had OS substitution near the branching points or
non-reducing ends, whereas OS starches from the second approach had OS groups distributed
randomly throughout the starch chains. A method of preparing OS starch by dry heating a
mixture of waxy maize starch and OSA was developed. The optimum reaction was investigated
and found to be pH 8.5 by addition of 3% NH4HCO3, 180 °C and 2 h. Reaction efficiency of ca.
90% was obtained at OSA levels from 1 to 6%. The OS starch had a DS of 0.0202 with 98%
solubility when reacted with 3% OSA. Transglucosidation occurred during the reaction. The OS
starch had a degree of branching of 19.8 %. The highly debranched OS starch showed excellent
emulsification property for vitamin E and vitamin A.
The structural changes of insoluble native waxy maize starch granules to cold watersoluble
pyrodextrin during dextrinization under acidic conditions were investigated. We
proposed that the starch was hydrolyzed by acid in the amorphous regions. Unwinding of the
double helices also occurred, and crystallite size decreased. Starch molecules were hydrolyzed
into small molecule fractions but remain in a radial arrangement. Glycosyl linkages including -
(1 2), -(1 6), -(1 2), and -(1 6) linkages were formed and the majority starch chain
terminals were 1,6-anhydro- -D-glucopyranose. Transglucosidation occurred during
dextrinization and the resulted pyrodextrin was highly branched.
| Identifer | oai:union.ndltd.org:KSU/oai:krex.k-state.edu:2097/35046 |
| Date | January 1900 |
| Creators | Bai, Yanjie |
| Publisher | Kansas State University |
| Source Sets | K-State Research Exchange |
| Language | en_US |
| Detected Language | English |
| Type | Dissertation |
Page generated in 0.0022 seconds