桉木半纤维素预提取的效果评价——两种测定方法之间的关系

Evaluation of Hemicellulose Pre-extraction Efficiency——The Relationship between Two Determination Methods

对桉木片分别进行碱预处理和热水预水解,采用间接法(差值计算法)和直接法(比色法)两种方法测定和计算了两种预处理条件下的戊聚糖的提取率。实验结果表明,两种测定方法所得戊聚糖提取率之间存在一定关系。对碱预处理试样,两种方法之间的关系为y=4.6682 lnx-5.5536,相关系数R2=0.9901;对热水预水解试样,两者之间呈现较好的线性关系,关系方程为y=0.5612x-1.2086,相关系数R2=0.9872(y与x分别表示比色法和差值法得到的结果)。因此,可以根据比色法的测定结果推算出预处理后木片的戊聚糖含量,从而用简单快速的比色法来评价预处理后木片的戊聚糖提取率。

Alkaline pretreatment and hot water prehydrolysis of eucalyptus chips were carried out. Two methods were used to determine and calculate the extraction yield of pentosan or pentose. One is indirect method, which is based on the difference of pentosan contents between the chips with and without pre-extraction. The other method is to directly measure the pentosan or pentose content in the extracting liquor with spectrophotometric method. The results indicated that there is certain relationship between the two methods. For the alkaline pre-extraction, the relationship can be expressed as y = 4.66821nx - 5. 5536 （ R2 = 0.990l ）. For the hot-water-hydrolyzed samples, good linear relationship is shown, which can be expressed as y = 0. 5612x - 1. 2086 （R2 = 0. 9872）, y and x in the equations represent the results from spectrophotometric method and differential approach, respectively. The pentosan content in the extracted chips can be calculated based on the equations and the spectrophotometric results. Therefore, a simple and rapid method of spectrophotometry can be used to evaluate the extraction yield of pentosan from the extracted chips.