Abstract:
BACKGROUND: An abundance of shiitake mushrooms is consumed in dried form around the world. In the present study,
changes in water state, water distribution and microstructure of shiitake mushrooms during hot-air drying (HAD) and
far-infrared radiation drying (FIRD) processes were investigated using low-field nuclear magnetic resonance and scanning
electron microscopy. Quality attributes of the dried products were compared in terms of drying property, appearance,
rehydration behavior, texture and storage stability.
RESULTS: Compared with HAD, the rate of water diffusion and evaporation of the shiitake mushrooms dried by FIRD was higher,
thus resulting in a shorter drying time (630 min), a lower water content (0.07 g g
temperature (7.88 ∘C) for dried products. Moreover, a homogenous and porous microstructure with less shrinkage and case
hardening was demonstrated by the FIRD samples, indicating a superior texture, including a larger pileus diameter (3.4 cm), a
higher rehydration ratio (7.31), a lower hardness (37.93 N) and a higher crispness (1.41 mm) for FIRD shiitake mushrooms.
–1
wet basis) and a higher glass transition
CONCLUSION: High-quality shiitake mushrooms with a desirable texture could be produced by FIRD by enhancing the diffusion
of internal water and alleviating the case hardening during a relatively short drying process.
