Isolation and structural characterization of amylopectin clusters from waxy rice starch and their applications in functional complex design
Abstract: ** Lecture will be given in English**
Starch, as the primary component of our daily staples, exhibits digestion characteristics that directly affect our blood sugar levels and overall health. Amylopectin is the major component of starch, accounting for approximately 65-85% of its total content. It is considered that the amylopectin primary limiting factor during enzymatic hydrolysis. However, due to its structural complexity, the precise mechanism by which amylopectin influences enzymatic digestion remains to be fully elucidated.
In this study, waxy rice starch (>99% amylopectin) was hydrolyzed using α-amylase (from Bacillus amyloliquefaciens) over varying durations to determine the reaction plateau. The hydrolysates at different time points were successfully isolated via anti-solvent precipitation. Systematic characterization and in vitro digestion assays revealed a highly branched “core” within the amylopectin structure that strongly resists further enzymatic cleavage, which we defined as the amylopectin cluster (APC).
Characterized by its highly branched nature and short chain lengths, the APC exhibits slow-digestion properties, highlighting its potential as a prebiotic material. To further explore its functional capabilities, the APC was complexed with lauric acid (LA) and caffeic acid (CA). Results demonstrated that the APC successfully formed complexes with both LA and CA, driven primarily by hydrophobic interactions and hydrogen bonding. The APC-LA complex exhibited increased slowly digestible starch (SDS) content, enhanced thermal stability, and improved hydrophobicity, suggesting its potential as a Pickering emulsion stabilizer. Furthermore, the APC-CA complex significantly increased the total yield of SDS and resistant starch (RS), while remarkably enhancing the antioxidant stability of CA.
Overall, this study successfully isolated and elucidated the inhibitory effect of amylopectin structural clusters on enzymatic hydrolysis, offering a novel strategy for using these clusters to develop digestion-resistant functional food complexes.
