Amylopectin chain length and molecular order steer digestibility of adzuki bean starch gels

Starches isolated from three Korean adzuki bean (Vigna angularis) cultivars show that molecular order governs digestibility while amylopectin chain-length distribution shapes gel rheology, according to a study published in Food Science and Biotechnology. The work examined Hongmiin, Hongda and Huinguseul starches, all of which displayed a C-type crystalline pattern with relative crystallinity ranging from 21.4 to 24.5 percent.

Hongmiin starch showed the highest crystallinity, gelatinization enthalpy and resistant starch content, which the authors interpret as a highly ordered and thermally stable structure. Hongda starch, by contrast, had the highest proportion of B1 chains with a degree of polymerization of 13 to 24, along with the greatest setback viscosity and the largest slowly digestible starch fraction, suggesting enhanced starch chain reassociation during cooling.

Huinguseul starch contained the highest proportion of very long amylopectin chains with a degree of polymerization of 37 or more and exhibited the greatest crossover strain, a measure the researchers link to superior deformation tolerance in the gel network. These cultivar-specific differences indicate that the fine structure of amylopectin, rather than bulk crystallinity alone, determines how the gels resist deformation.

The study, which investigated the relationships among amylopectin chain-length distribution, molecular order, starch digestibility and gel rheology, concludes that molecular order controls digestibility whereas chain-length distribution determines gel network stability and rheological behavior.

Subject of Research: Structure–function relationships of adzuki bean starch gels (pat-muk) in three Korean cultivars

Article Title: Effects of amylopectin chain-length distribution and molecular order on starch digestibility and rheological properties of adzuki bean starch gels (Pat-muk)

Article References: Sim, E., Ju, Y. K., & Jung, Y. H. (2026). Effects of amylopectin chain-length distribution and molecular order on starch digestibility and rheological properties of adzuki bean starch gels (Pat-muk). Food Science and Biotechnology. https://doi.org/10.1007/s10068-026-02284-9

Image Credits: AI Generated

DOI: 10.1007/s10068-026-02284-9

Keywords: adzuki bean, starch digestibility, amylopectin, chain-length distribution, molecular order, resistant starch, rheology, pat-muk, crystallinity, Vigna angularis, Effects, chain-length