Experiment and research on the techniques for microwave vacuum drying of Pteridium aquilinum

Pteridium aquilinum is a wild vegetable with special favor, which is characterized of very short shelf life and high nutrition value. Microwave Vacuum Drying (MVD) method was used to dry the Pteridium aquilinum quickly based on an orthogonal experimental design to determine the drying properties. Contrasting the microwave vacuum drying method with freeze drying method and hot air drying method, the qualities of dried Pteridium aquilinum were analyzed. During the MVD process for the Pteridium aquilinum, the effect of the microwave power on the drying rate was greater than that of the vacuum degree. A regression model between the moisture content of the Pteridium aquilinum and MVD parameters including microwave power, vacuum degree and drying duration was established. The Pteridium Aquilinum dried by microwave vacuum drying method showed perfect rehydration characteristics, which obviously excelled that dried by hot air and freeze drying method. The quality indexes such as color and vitamin C of the dried Pteridium Aquilinum with the MVD method were quite similar to those with freeze drying method, which had a remarkable advantage over those with hot air drying method. Therefore, MVD is a potential technology for drying Pteridium aquilinum.