不同干燥条件大黄水提物的外观及理化性质比较研究

目的研究不同干燥方式对大黄水提物外观及理化性质的影响。方法分别采用真空、常压、喷雾、微波和冷冻干燥等5种不同干燥方式对大黄水提物进行干燥，测定并比较各样品的外观质地、pH及相对临界湿度（CRH）的差异。结果不同干燥方式样品的外观性状差异较大，pH差异不大；CRH由大到小依次为常压干燥、微波干燥、真空干燥、冷冻干燥、喷雾干燥样品，其中喷雾干燥样品最小且与常压干燥样品有显著差异（P〈0．05）。结论干燥方式对样品的外观及理化性质影响明显。喷雾干燥样品的吸湿性增大，对产品的稳定性有一定影响。

Appearance and Physical Property of Rhubarb Water Extract by Different Drying Methods

Objective To investigate the effects of different drying methods on the appearance and physical property of water extract from rhubarb（RUB）.Methods RUB was dried by normal drying, vacuum drying, spray drying, microwave drying and freeze drying, respectively. The appearance, texture, pH and relative critical humidity（CRH）of different drying samples were determined and compared. Results The appearance of RUB dried by different methods was notably different, and pH had little difference. The decreasing order of CRH in samples was： normal drying, microwave drying, vacuum drying, freeze drying and spray drying. Among them, CRH in samples by spray drying was least and had significant difference compared with that by normal drying（P〈0.05）. Conclusion There is obvious impact in appearance and physical property of rhubasb by different drying methods. The hygroscopicity of samples by spray drying is increased so that its stability decreases.