Temperature effect on retrogradation rate and crystalline structure of amylose

• Published in: Carbohydrate polymers 1997-05, Vol.33 (1), p.19-26
• Main Authors: Lu, Ting-jang, Jane, Jay-Iin, Keeling, Peter L.
• Format: Article
• Language: English
• Subjects: Applied sciences; Biological and medical sciences; Exact sciences and technology; Food industries; Fundamental and applied biological sciences. Psychology; Natural polymers; Physicochemistry of polymers; Starch and polysaccharides; Starch and starchy product industries
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/S0144-8617(97)00038-6

Commercial potato amylose was used to study temperature effects on the retrogradation of amylose solutions (3.5mg/ml). The retrogradation rate decreased as incubation temperature increased (5 to 45 °C). The degree of retrogradation within 24 h decreased from 58.8 to 7.1% as incubation temperature increased from 5 to 45 °C. In the amylose solution, different-sized molecular subfractions retrograded at different rates. After incubating at 5 °C for 100 days, the majority of the amylose molecules retrograded and precipitated from the solution; at 45 °C, only amylose of the small-molecular subfraction (number average, DP n = 110; weight average, DP w = 150) retrograded and precipitated. Entanglement of molecules was observed in size exclusion chromatograms. The morphology of retrograded amylose observed by using a scanning electron microscope differed with the retrogradation temperature. The chain length of amylose crystalline segments, prepared by hydrolysis of retrograded amylose, showed a narrow distribution (polydispersity from 1.21 to 1.67). The chain lengths of resistant segments increased DP n from 39 to 52 and DP w from 47 to 72 for α-amylolysis and DP n from 34 to 40 and DP w from 48 to 67 for 16% sulfuric acid hydrolysis, when incubation temperature increased from 5 to 45 °C.