Physical Properties of Amylodextrin and a Microwave Assisted Method for its Production
Date Issued
2006
Date
2006
Author(s)
Chen, Chun- Ming
DOI
zh-TW
Abstract
Amylodextrin was obtained by soaking corn starch in 2.2N HCl solution at 35℃for 8 days. Molecular-weight distribution of starch was
significantly changed, as ratio of hydrolyzed starch reached at 3.1%. Both
amylopectin and amylose degraded, and some low molecular- weight
amylodextrin presented, as acid hydrolysis proceeded. Amylodextrin used
for this study was harvested from batches of acid hydrolysis with average
of hydrolyzed starch ratio at 60.6%. Size-exclusion chromatogram of this
amylodextrin showed a narrow peak, and the number-average degree of
polymerization (DPn) and weight-average DP (DPw) were 21 and 25,
respectively, with polydispersity value being equaled to 1.17. The average
chain-number was 1.19 calculated from difference of chain-length of
amylodextrin before and after debranched reaction by isoamylase. The
results indicated that amylodextrin was an essential linear molecule with
narrow size distribution. Transition temperature of amylodextrin was
higher than gelatinization temperature of native corn starch. After
annealing, the transition temperature was increased from 63.1°C to
84.8°C; the transition temperature range was narrowed from 42.42°C to
22.74°C. It indicated that annealing promoted reorganization and
perfection of crystalline lamellae of amylodextrin. Amylodextrin
suspension was a Newtonian fluid. Addition of amylodextrin to 0.5% or
1% guar gum hydorcolloid caused a synergistic increase in viscosity. To
shorten the preparing time of amylodextrin, microwave heating was
employed to accelerate the heterogeneous acid hydrolysis. Amylodextrin
with 117~123 DP and 1.3~1.36 polydispersity could be obtained from
heating corn starch in 2.2N HCl for 70 ~ 75 seconds to hydrolyze 59.5 ~
66.2% of mass.
Subjects
澱粉糊精
酸修飾澱粉
微波
amylodextrin
acid modified starch
microwave
Type
thesis
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