枸杞多糖在真空带式干燥机中的干燥工艺

Drying Technology of Lycium Barbarum Polysaccharides in Vacuum Belt Dryer

以干燥后产品的湿基含水量和溶液黏度为质量指标,研究了湿基含水量为20%的枸杞多糖在真空带式干燥机中的干燥工艺.对于枸杞多糖这类易发泡的物料,在真空带式干燥机中进行干燥时,第一加热区的温度不能过高,以避免物料发泡后料层过于疏松,导热系数降低,影响热量在料层内自下而上的传递,导致下层物料温度过高,影响产品溶液黏度;而上层物料因热量不足,水分蒸发量少,影响产品干燥.在本实验中,四区加热板的温度为120、110、100、30,℃,操作压力1,000,Pa时产品质量最好,此结果为工业生产提供参考依据.

Lycium barbarum polysaccharides with 20% moisture content were dried in a vacuum belt dryer. The moisture content and solution viscosity of the dried product were quality index in this investigation. The results show that the tempera- ture in the first heating area cannot be set too high so as to prevent the materials form losing too much. Otherwise, the re- duced thermal conductivity would influence the heat transfer from bottom to top in the material layer;the solution viscosity of the dried product would be reduced due to the higher temperature of the bottom material ; while the moisture content of the dried product located on the top of the material layer would be higher because of the reduced heat transfer. In this experiment, the best operating parameters are 120, 110,100,30℃, and the operating pressure is 1 000 Pa. The results can be of great help to industrial production.