Intelligent temperature-humidity control during hot-air drying of s hiitake mushroom ( Lentinus edodes ): Effects on drying behavior and flavor quality

Drying temperature and relative humidity (RH) govern flavor formation in dried shiitake mushrooms, yet their combined effects remain unclear. Using a smart drying system, four conditions (40 °C-20% RH, 40 °C-40% RH, 60 °C-20% RH, 60 °C-40% RH) were evaluated. Higher temperature or lower RH accelerated drying and moisture diffusivity, with 60 °C-20% RH being the most efficient, while 40 °C-20% RH the better preserved structure and color. Free amino acids (FAAs) and equivalent umami concentration (EUC) were synergistically regulated by combined temperature-RH conditions. For volatile compounds, 40 °C promoted retention of alcohols, while 60 °C enhanced sulfur compounds. Five key flavor compounds were identified via relative odor activity values (ROAV) and variable importance in projection (VIP). Partial least squares (PLS) analysis indicated RH had a greater impact than temperature on drying quality. Overall, the synergistic regulation of temperature and humidity can optimize both drying efficiency and flavor quality in shiitake mushrooms.