Abstract: The effect of hot-air drying (HAD), short- and medium-wave infrared radiation drying (IRD) and freeze drying (FD) on the rehydration properties of dried shiitake mushrooms and the quality of rehydrated mushrooms was studied in order to obtain dried shiitake mushroom with better rehydration properties. The results showed freeze dried mushrooms had higher rehydration rate than the dried samples obtained by HAD and IRD, which was attributed to the high porous structure. The highest rehydration ratio (9.22) was reached at 60 min and the rehydrated product was similar in appearance to the fresh sample. Moreover, the shear force and chewiness of the rehydrated FD mushroom were 1 352.99 and 232.54 g, respectively, which were smaller than those of other rehydrated dried samples, indicating that the rehydrated FD mushroom was soft and easy to cut. Additionally, there was no difference in the aroma of rehydrated samples of shiitake mushrooms dried by HAD, IRD and FD, as indicated by similar electronic nose response curves. Furthermore, higher contents of protein (0.42 mg/g) and VB2 (0.71 × 10-3 mg/g) were detected in the rehydration solution of FD shiitake mushrooms compared with other dried samples, suggesting that FD samples are rich in nutrients and the nutrients are more easily dissolved during processing. In conclusion, FD has the potential to be used to produce high-quality dried shiitake mushrooms with better rehydration properties.

Key words: shiitake mushroom, rehydration property, texture profile analysis, flavor, nutrient dissolution