Impact of airborne ultrasound on pore characteristics and cell wall components in shiitake mushrooms during microwave vacuum drying

The pore structure of dried products dictates their rehydration, flavor retention, and processing adaptability, thus affecting market potential. This study investigated the impact of ultrasound amplitude on pore structure evolution in shiitake mushrooms during microwave vacuum drying (MVD). Results showed dried shiitake porosity first increased then decreased with rising amplitude: maximum porosity (65.13%) was achieved at 60% amplitude, and the largest average pore size (3041.78 nm) was observed at 70%. Ultrasound modified shiitake cell wall components via cavitation, mechanical vibration, and enzyme activity regulation, ultimately influencing pore structure. At 50%-70% amplitude, ultrasound accelerated cell wall degradation and induced pore expansion; above 70%, excessive energy reduced enzyme activity and caused pore collapse. This study offers insights for regulating the pore structure of dried products and clarifies the mechanism by which ultrasound affects pore structure.