吸附干燥工艺条件对川白芷有效成分及形貌影响的研究

Study on Technical Conditions of Adsorption Drying of Angelica Dahurica and their Effects on Microscopic Feature of the Angelica Dahurica

在吸附式低温干燥实验装置上进行了川白芷吸附干燥实验研究,考察了干燥介质温度、相对湿度、空速、试样切片厚度对白芷中欧前胡素和总香豆素含量的影响,用正交实验优选适宜干燥工艺条件;用扫描电镜(SEM)对干燥前后白芷不同部位的细胞组织形貌变化进行了分析。结果表明:对要求干燥后白芷的最终含水率≤14%的情况下,吸附干燥川白芷适宜的工艺条件为:温度35℃,干燥介质相对湿度3%,空速3.54 s 1,切片厚度约为2～3 mm;干燥后白芷中欧前胡素含量为0.40%,总香豆素含量为2.01%。干燥介质空速对川白芷中欧前胡素含量的影响最为显著,干燥温度是影响川白芷中总香豆素含量的主要因素。吸附干燥前后白芷的木栓层、韧皮层、形成层细胞组织形貌变化显著,皮层和木质层细胞组织形貌变化较小。

The drying process of angelica dahurica was performed by using a low-temperature adsorption drying experimental device. The effects of drying medium temperature, relative humidity and space velocity of drying medium and slice thickness of the angelica dahurica specimen on the contents of imperatorin and coumarin in the dried angelica dahurica were investigated. The suitable drying conditions were optimized with the orthogonal experiments. The microscopic features of the angelica dahurica were characterized by SEM （Scanning Electron Microscope）. The results show that, to get a product with water content （dry basis） lower than 14%, the optimal drying process conditions are as follows： the drying air of 35℃ and with 3% average relative humidity, space velocity of 3.54 s^-1 and slice thickness of 2-3 mm; under above conditions, the contents of imperatorin and coumarin in the dried product are 0.40% and 2.01%, respectively. It was found that the space velocity of the drying medium is the key factor for the imperatorin content, while the drying temperature is the main factor affecting the coumarin content. The microscopic features of the cork layer, the bast zone and the cambium layer tissues of angelica dahurica will be damaged distinctly after adsorption drying process, while none obvious change can be observed in the cortical layer or the wood layer tissues of the angelica dahurica.