谷物中非淀粉多糖组份糖醛酸的分光光度测定

Determination of the Uronic Acid Constituents of NonStarchPolysaccharides in Cereal Products by Spectrophotometric Assay

糖醛酸为非淀粉多糖中的组分之一，浓Ｈ２ＳＯ４和糖醛酸在７０℃时，反应可以生成５－甲酰基－２呋喃甲酸，该化合物可以用选择性极强的３．５－二甲基酚显色，并在４５０ｎｍ波长处产生最大吸收．研究了用分光光度法，３．５－二甲基酚作显色剂，以４００ｎｍ作参比波长，４５０ｎｍ作测定波长这种双波长测定法，可消除样品中木质素和中性糖等化合物的干扰，提高糖醛酸测定的准确度，利用本法测定出了几种谷物中非淀粉多糖组分糖醛酸的含量．

Uronic Acid is one of constituents of nonstarch polysaccharides.A colourimetric reagent,3.5dimethylphenol,is selective for 5formyl2furancarboxlic acid which can be formed from Uronic Acid in concentrated H2SO4 at 70 ℃,a chromogen absorbing at 450nm,the 400nm wave length as a reference.The double wave length can avoid the interference from lignin and neutral sugar products and increased the accuracy of results of measuring Uronic Acids.We used the method for measurement of Uronic Acid in several cereal products.