Structural properties of starch from single kernel of high-amylose maize

Cereal grain weight is an important agronomic character, influencing crop yield and quality. The high-amylose cereals usually have grains with different weights. However, it is unclear whether starches from kernels with different weights have different structural properties. In the research, the amylose content, amylopectin structure, crystallinity, and thermal properties of single-kernel starch were investigated in two high-amylose maize inbred lines, and the relationship between amylose/amylopectin content and kernel weight and the differences of starches from kernels with different weights were analyzed. The results showed that kernel weight had significantly positive relationship with amylose content and amylopectin B3+ chains (DP > 36) and average branch-chain length and negative relationship with amylopectin A chains (DP6-12) and B1 chains (DP13-24). The amylopectin A and B1 chains, relative crystallinity, and ordered degree had positive relationship with each other. The amylose content, amylopectin B3+ chains and average branch-chain length, and gelatinization temperature range were positively correlated with each other. Starches from kernels with different weights had different amylose contents, amylopectin structures, and thermal properties. The above results would offer references for breeding of high-amylose cereal crops and applications of grains with different weights.