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目的:研究低真空度下冷冻干燥技术在中药鲜品保存方面的可行性。方法:以含热不稳定性成分的地黄和含挥发性成分的生姜为研究对象,分别对药材进行低真空度下冷冻干燥和鼓风干燥。以干燥后药材的外观、含水量、显微结构、指标性成分含量、复水性为指标,对比2种干燥方法的效果。结果:低真空度下冷冻干燥组药材的色泽鲜明、形态完好;鼓风干燥组药材的色泽暗黑、形态皱缩。低真空度下冷冻干燥组药材的含水量低于鼓风干燥组药材。低真空度下冷冻干燥和鼓风干燥都未破坏药材显微构造,低真空度下冷冻干燥组中梓醇和6-姜辣素的保留率均显著高于鼓风干燥组,而2种干燥技术对药材中挥发性成分含量的影响无太大差异。低真空度下冷冻干燥后的地黄药材在1 h内吸水增重292%,吸水达到恒重时增重300%,其具有良好的吸水性,并且感官质量较高;而鼓风干燥后的地黄药材4 h吸水增重220%,随后不再增重。结论:低真空度下冷冻干燥产品外观质量好,含水量低、显微结构完整、指标性成分保留率高、复水分性良好,是一种优良的干燥技术,在中药鲜品的保存中极具应用潜力。
Objective: To study the feasibility of freeze-drying technology in preserving fresh Chinese medicines under low vacuum. Methods: Rehmannia glutinosa and volatile components-containing ginger were used as the research objects. The samples were respectively freeze-dried and air-dried under low vacuum. The effects of two drying methods were compared with the appearance, water content, microstructure, index content and rehydration of dried herbs. Results: The freeze-dried herbs with low degree of vacuum had distinct color and good morphology. The herbs of blast-dried group had dark color and wrinkled form. The water content of freeze-dried herbs under low vacuum was lower than that of dried herbs. Low vacuum degree of freeze-drying and blast drying did not destroy the microstructure of medicinal materials, low vacuum degree freeze-dried group Catalpol and 6-Gingerol retention were significantly higher than the blast drying group, and two drying techniques There is not much difference in the content of volatile components in medicinal materials. The freeze-dried Rehmanniae Radix under low vacuum had a water absorption weight gain of 292% within 1 h and a weight gain of 300% when the water absorption reached constant weight, which showed good water absorption and high sensory quality. However, Medicine 4 h water absorption weight gain 220%, then no longer gain weight. Conclusion: Under the condition of low degree of vacuum, freeze-dried product has good appearance, low water content, complete microstructure, high retention rate of indicator components and good rehydration. It is an excellent drying technology. With application potential.