Using ultrasound-assisted microwave vacuum drying, researchers found that shiitake mushrooms (Lentinula edodes) developed the strongest aroma at 70% ultrasonic amplitude, which boosted key sulfur compounds to 33.88 ng/g. At this setting, enzyme activity linked to shiitake’s signature flavor jumped sharply, including a 134% increase in C–S lyase activity, driving higher production of compounds like lenthionine. Higher intensity (90%) actually dulled flavor by shifting metabolism toward stress and energy maintenance, showing that precise drying settings directly control taste quality in dried shiitake.