Research Topic: Porous starch from dual-amylase hydrolysis: structure, regulation and functional application
Abstract: ** Lecture will be given in English**
Starch is a highly abundant biopolymer whose native granules vary across botanical origins. Porous starch is fabricated by generating interconnected pores while preserving granular integrity; subgelatinization amylolysis serves as an efficient preparation route.
We investigated evolutions in morphology, porosity, and physicochemical properties during synergistic dual-enzyme (α-amylase and γ-amylase) modification of three maize starches. Random endo-cleavage by α-amylase yields abundant non-reducing ends, accelerating inward hydrolysis by exo-acting γ-amylase within the alternating amorphous–crystalline lamellae. To regulate this reaction, we proposed the Granular Starch Hydrolysis Unit (GSHU), a flexible parameter that reflects reducing sugar release and quantifies starch susceptibility to enzymatic attack. Benefiting from uniformly distributed branch points and inherent surface nanopores, A-type starches reached optimal porosity under enzyme dosages predicted by GSHU. Importantly, this predictive performance remained effective even after high-pressure pretreatment (400 MPa, 10 min). To resolve internal architectures, epoxy-resin-embedded granules were cut into 100-nm ultra-thin sections for cross-sectional SEM observation. Focused ion beam (FIB) milling allowed sequential imaging at 100/200 nm intervals, and the serial micrographs were reconstructed into three-dimensional models using Amira software. Finally, curcumin-loaded prolamin nanoparticles were successfully incorporated into porous starch, greatly enhancing the stability and bioaccessibility of this hydrophobic polyphenol.
Overall, this work provides key insights into enzymatic starch modification and lays a solid foundation for the design of advanced functional starch-based materials.
