One of the most characteristic features of starch is the formation
of the blue complex with iodine which can be very useful
for analysis of changes in its degree of polymerization (DP) caused
by enzymatic, chemical or physical modifications (Sujka & Jamroz,
2013). The absorbance of the resistant starch from 500 to 800 nm
was shown in Fig. 4(C). All of GP-LRS3, MP-LRS3 and UP-LRS3 displayed
a maximum absorption peak (560–610 nm). All samples
had sharp maximum absorption peaks, suggesting that resistant
starch had a relatively centralized distribution of molecular
weight. These results were consistent with the results by SECMALLS–
RI system. Among the three samples, the DP value of UPLRS3
was greatest while MP-LRS3 was the smallest. UP-LRS3
exhibited the strongest iodine absorption ability while MP-LRS3
was weakest, which was consistent with the results of their degree
of polymerization. Therefore, the iodine absorption ability of LRS3
was affected by the degree of polymerization.