Effects of preparation temperature on gelation properties and molecular structure of high-amylose maize starch

Citation
E. Vesterinen et al., Effects of preparation temperature on gelation properties and molecular structure of high-amylose maize starch, CEREAL CHEM, 78(4), 2001, pp. 442-446
Citations number
16
Categorie Soggetti
Agricultural Chemistry
Journal title
CEREAL CHEMISTRY
ISSN journal
00090352 → ACNP
Volume
78
Issue
4
Year of publication
2001
Pages
442 - 446
Database
ISI
SICI code
0009-0352(200107/08)78:4<442:EOPTOG>2.0.ZU;2-D
Abstract
In this study, 3% aqueous high-amylose maize starch (Hylon VII) dispersions were heated to temperatures of 140-165 degreesC. The onset and rate of gel formation was observed using a small-strain oscillation rheometer as a fun ction of temperature from 90 to 25 degreesC. The gel formation clearly bega n earlier in high-amylose starch paste preheated at lower temperatures, but the rate of gelation was slower and the resulting gel was weaker in compar ison with starch pastes preheated at higher temperatures. In addition, the structure of the final gels was studied using large deformation compression measurements. The most rigid gel structure on the basis of small and large deformation tests was obtained for high-amylose starch gel preheated to 15 0-152 degreesC, depending on the type of measurement. The rate of gelation was also fastest in that temperature range. High-amylose gels heated to hig her temperatures lost their rigidity. The molecular weight distribution of starch molecules was measured by size-exclusion chromatography. Heating cau sed extensive degradation of amylopectin, which had a great effect on amylo se gel formation and the final gel properties of high-amylose maize starch. Micrographs of Hylon VII gels showed that phase separation of starch compo nents visible in light microscopy occurred on heating to higher temperature s.