Iodine binding to explore the conformational state of internal chains of amylopectin

On the molecular structure of the amylopectin fraction isolated from “high-amylose” ae maize starches

“…The slightly higher max values of LMF ( Fig. 1) suggested that LMF contained longer segments, potentially also between branches [68], that were prone to interact with iodine and also interacted with the -amylase and gave rise to the smaller fragments that the enzyme released. This was supported by the fact that the isolated clusters were smaller from the HYLON starch samples than from NMS.…”

Enzymatic modification of corn starch with 4-α-glucanotransferase results in increasing slow digestible and resistant starch

“…The absorbance value of amylopectin-iodine is much lower than that of amylose. The iodine-binding capacity of pure amylose was reported to be 19-22% of its weight, whereas for amylopectin it was about 1% [26]. As the length of the starch chain decreased with the extent of enzymatic modification (Fig.…”

“…They also reported that there were several possible fates of amylose on 4␣GT treatment: (a) segments of amylose chains could be transferred to amylopectin branch chains by Both amylose and amylopectin can bind iodine to form a color complex, which is measured spectrophotometrically to estimate the affinity of the polysaccharide structure for iodine. The absorbance and the wavelength of the maximum absorbance ( max ) varies in the spectrophotometric method depending on the degree of polymerization (DP) and the structural properties of the starch molecules, which determine the composition of the polyiodine chains complexed with the linear chain helices [26,30]. Amylose has high iodine absorption values and amylopectin with many short linear chains displays low values.…”

“…The iodine binding analysis was measured using a UV/visible Spectrophotometer (UV-2102PC, Unico Instrument Co., Ltd., Shanghai, China) according to the method described by Shen et al [26]. An iodine reagent was prepared by adding 2 mg of I 2 and 20 mg of KI to 1 ml of deionised water.…”

Understanding Starch Structure: Recent Progress

“…Indeed, Vamadevan et al [240,264] showed that both annealing and the onset gelatinisation temperature positively correlate with IB-CL. Another indication of the nature of the backbone is the interaction of the β-limit dextrin of amylopectin with iodine, which gives rise to a faint colour at low wavelengths (λ max is about 507~540 nm) [96,265,266]. As the β-LD lacks external chains, the result shows that the backbone possesses segments long enough to interact with iodine, i.e., these segments, which presumably are longer inter-block segments, form single-helices and inclusion complexes with iodine.…”