Microwave irradiation benefits fructan degradation in sourdough steamed cake by tunning the β-fructosidase FosE-substrate interaction

Producing low FODMAP grain-based staple foods is crucial for individuals with irritable bowel syndrome (IBS). This study aimed to resolve the impact of microwave heating on the fructan content in sourdough steamed cake and to elucidate the potential mechanism by which microwave fields activate β-fructosidase FosE. With similar heating rate, microwave treatment induced a significant reduction of fructans in sourdough steamed cakes compared to conventional steaming method, and this was confirmed to be the result of enhanced FosE activity by microwaves irradiation. Molecular docking and molecular dynamics simulations revealed that microwave irradiation improves the structural stability of the enzyme-substrate complex. Analysis of binding free energy indicated that microwaves enhance the coulombic interactions through energy transfer. These findings provide valuable insights into the molecular mechanisms underlying the interactions between FosE and fructan under microwave irradiation, paving the way for the future applications of microwaves in low-FODMAP cereal-based food processing.