Tuning high-concentration wheat starch gel properties via chain-length-controlled hydrogen bond networks.

This study investigates how chain length distribution (CLD) affects the properties of high-concentration wheat starch gels. Results show that the content and length of amylose have a significant inhibitory effect on swelling ability, and the key role is to construct the overall skeleton of hydrogen bond network. A higher proportion of medium-chain amylose causes network collapse under stress. Microscopy reveals distinct gel structures formed by different CLDs. However, amylopectin modulates gel architecture primarily by tuning lattice parameters. Specifically, A chains (degree of polymerization 6-12, DP 6-12) influence double-helix packing density and lateral cell dimensions, while B1 (DP 13-24) and B2 chains (DP 25-36) jointly determine lattice size and volume. Excessively long B3 chains (DP > 36) reduce short-range order. Dense amylose hydrogen-bond networks and rigid crystalline junctions together promote uniform, compact gels. Thus, programming chain-length features enables rational design of gel mechanics through controlled crystallization and networking.