蔗渣膳食纤维化学结构的研究(Ⅳ)──挤压蒸煮对化学结构的影响

蔗渣细胞壁物质（膳食纤维）整体的化学成分与单糖组成不随双螺杆挤压蒸煮而发生变化。细胞壁物质中80℃H2O分级组分的相对含量会因挤压蒸煮处理而由原来的24％提高到13．3％，且分子的Xyl：Ara比值由原来的6．2减小到4．2；1mol／LNaOH分级组分的相对含量则由原来的189％减少到11．2％，分子Xal：Ara比值由原来9．3增加至11．4。挤压蒸煮对这2种分级组分的聚合物基本结构没有影响，但会使lmol／LNaOH分级组分发生增溶作用或断裂部分连接键，导致其分子量下降，分子更趋于直线型，分支程度减小，其中有部分转变成80℃H2O分级组分。

Studies on the Chemical Structure of Dietary Fibre from Bagasse (Ⅳ)──Effects of Extrusion-cooking on Chemical Structure

No effect caused by twin -screw extrusion-cooking was found on the chemicalcompositions and monosugar compositions of the whole cell wall material (dietary fibre)from bagasse. The relative content of polymeric fraction soluble in 80℃ water rose from 2.4% to 13. 3%after extrusion -cooking of bagasse CWM, and its ratio of Xyl: Ara in themolecule reduced frorn6- 2 to 4. 2. The relative content of polyrneric fraction extracted with1mol;/L sodium hydroxidereduced from 18. 9 94 to 11. 2%, and its ratio of Xyl: Ara in themolecule rose from 9. 3 to 11. 4. The fundamental structure of such two polymeric fractionswere almost not affected, but the extrusion-cooking treatment would lead the solubilisationof 1mol/L sodium hydroxide fraction or cause some bonding linkages broken, turn to belower molecular weight, more linear molecule and less branched structure, some of whichthen changed into the fraction soluble in 8O C water.