Effects of Five Different Drying Methods on Drying Characteristic and Quality of Hippophae rhamnoides

Fresh Hippophae rhamnoides L. fruits from Altay were used as material, the treatments with shading drying (NSD), natural drying (ND), hot air drying (HAD), heat pump drying (HPD) and vacuum freeze-drying (VFD) were compared for their application to the drying of Hippophae rhamnoides L., and effects of the five drying methods on the drying characteristics and quality of Hippophae rhamnoides L. were analyzed. The results showed that among the five drying methods, HAD and HPD had short drying times which were 118 and 124 h respectively, and the drying rate was 100%. The drying time was more than 3 times shorter than NSD and ND, and the drying rate increased 5 times more than them. After VFD for 120 h, the drying rate was only 27.67%. If the drying time continued to increase, the drying efficiency remained basically unchanged, and the freeze-drying efficiency was low. Compared with the fresh samples, Hippophae rhamnoides fruits dried by VFD could keep the better quality, and show the brightly yellow color, hold the lower browning, and maintain the higher V_C and total phenols content. In terms of drying efficiency, HAD and HPD were suitable for drying of Hippophae rhamnoides. However, in terms of the quality of dried products, VFD had a better effect.