Progress in C-type starches from different plant sources

Amylopectin forms A-and B-type crystallinity in native starch. Starches in higher plants are classified into A-, B-, and C-type starches according to their crystalline types. A-and B-type starches contain only A-and B-type crystallinity, respectively, but C-type starch contains both A-and B-type crystallinity. Therefore, C-type starch is more complex than A-and B-type starch, and has special properties according to the distribution and the proportion of A-and B-type polymorphs. Compared with A-and B-type starches, which have been widely studied and utilized, C-type starch is little reported, especially in allomorph distribution. This review summarizes the progress of C-type starch, including plant source, morphology and size, molecular structure, allomorph distribution, physicochemical property, environment effect, and modification of C-type starch. Some plant seeds, tubers, rhizomes, roots, and fruits contain C-type starches. Their morphology and size, molecular structure, allomorph distribution, and properties are significantly different due to their different plant sources. Environment has obvious effects on the proportion of A-and B-type polymorphs and the physicochemical properties of C-type starch. Some modifications of C-type starch have been summarized. Future research directions on how to better understand and utilize C-type starches are suggested. (C) 2017 Elsevier Ltd. All rights reserved.