栓皮栎栲胶的提取工艺技术研究

采用单因素试验和L₉(3⁴)正交试验相结合，Folin-Denis分光光度法方法测定单宁含量，利用优化的栓皮栎橡碗栲胶提取工艺，对秦岭北坡4种类型栓皮栎的橡碗、树皮、叶片和枝条的单宁含量进行了测定和差异分析。结果表明:1)提取温度对栓皮栎橡碗单宁提取的影响程度最大，其次是料液比和乙醇体积分数，提取时间对单宁提取的影响程度最小。2)乙醇提取厚皮深裂型栓皮栎橡碗单宁的适宜工艺为体积分数70%乙醇溶液，料液比为1∶15，在80℃条件下提取4 h。3) 秦岭北坡4种类型栓皮栎各器官的单宁含量存在显著或极显著差异，4种类型栓皮栎均为橡椀单宁含量最高（15.686%~15.895%），其次是树皮（8.743%~9.274%）和叶片（6.549%~7.151%），枝条（4.515%~4.925%）中单宁含量最低。4)橡椀、树皮、叶片和枝条的单宁含量均以厚皮深裂型栓皮栎最高，薄皮浅裂型的最低。秦岭北坡厚皮深裂型栓皮栎的橡椀、树皮、叶片是提取栲胶的良好工业原料。

Research on Extraction Technology of Tannins from Quercus variabilis

This study aimed to illustrate the suitable technology to extract tannins from from Quercus variabilis by ethanol and to understand the variations of tannin content in different organs of Q. variabilis from four types（thick bark with deep crack , thick bark with shallow crack, thin bark with deep crack, thin bark with shallow crack）occurring in northern Qinling Mountains and to provide a theoretical reference for rational development and utilization in tannin resources of Q. variabilis. Single factor test and orthogonal experiment L₉ (3⁴) were adopted to optimize the suitable extraction process, in which the tannin content was measured by Folin-Denis method. The results were showed concretely as follows. 1) The effect of extraction temperature on tannin extraction of valonea from Q. variabilis was significant followed by the ratio of solvent to material and the concentration of ethanol, the influence of extraction time was minimum. 2) The optimized extraction parameters were: ethanol concentration: 70%, the ratio of ethanol to material: 15∶1, extraction temperature: 80℃, extraction time:4 hours. 3) The tannin content in different organs were all different significantly (p＜0.05 or p＜0.01) among the four types of Q. variabilis in northern Qinling Mountains. The highest tannin contents were found in valonea were (15.686%-15.895%), followed by the bark (8.743%-9.274%), leaf (6.549%-7.151%), lowest in branch (4.515%-4.925%). 4) The type of thick bark with deep crack were found the highest tannin content in all the organs, such as valonea, bark, leaf, and branch, lowest in thin bark with shallow crack type. The valonea, bark and leaf of Q. variabilis from thick bark with deep crack type in northern Qinling Mountains were suitable industrial raw materials for tannin extraction.