Study on the mechanism of flavor development in ultrasound-assisted microwave vacuum drying of shiitake mushrooms: Dosage effect of ultrasonic amplitude.

Metadata-grounded summary

Citation abstract

In this study, the regulatory pathways of aroma formation in dried shiitake mushrooms under different ultrasound amplitudes (50 %, 70 %, and 90 %) were elucidated using GC-MS and non-targeted metabolomics combined with dynamic analysis of γ-GT and CS lyase activities. The results revealed that multiple metabolic pathways including cysteine and methionine metabolism, nucleotide metabolism, and cofactor biosynthesis exhibited amplitude-dependent responses. These pathways collectively influenced aroma compound production through coordinated resource allocation and signal regulation. Specifically, low and medium ultrasound amplitudes (50 % and 70 %) significantly enhanced cysteine and methionine metabolism, resulting in an increase of volatile sulfide content (up to 33.88 ng/g). Notably, ultrasound at 70 % amplitude markedly promoted sulfur metabolism and methylation processes, which contributed to a more complex and intense aroma characteristic of shiitake mushrooms. However, high-amplitude ultrasound induced metabolic offset, activating energy and nucleic acid metabolism to sustain basic cellular functions under stress, which limited the flavor development. Besides, ultrasound at 70 % amplitude was found to facilitate the release of enzymes in cells, increasing the activity of CS lyase by 134 % compared to the MVD group, which enhanced the formation of volatile sulfur such as lenthionine. These findings provide theoretical support for aroma regulation in dried edible mushrooms and offer new insights for optimizing high-quality drying processes in shiitake mushroom production.