Effect of Different Moisture Contents on Crystallized State of Microwave Modified Tapioca Starch

Effect of microwave modification on tapioca starch at different moisture contents was studied with polarized light microscope. It was observed that loss of birefringence was initiated at hilum of granule. The polarization cross of most granules had become somewhat unclear, and reduction in clarity of the polarization cross was proportioned with the moisture contents of native starch as modification by microwave. When the moisture contents reached to 35.0%, the polarization cross of most granules was lost, and the critical point of native starch was 30% in microwave modification.

水分对微波变性木薯淀粉晶体颗粒态的影响

利用偏光显微镜研究了不同水分质量分数对微波变性木薯淀粉的影响,发现微波处理造成颗粒偏光十字的消失始于脐点,经过微波变性绝大多数颗粒偏光十字的亮度有所下降,偏光消失的程度与微波变性时原淀粉的水分质量分数成正比。当水分质量分数达到35.1%时,绝大多数颗粒的偏光消失,微波变性时原淀粉的水分临界点为30%。

水分对微波变性木薯淀粉颗粒物态性质的影响

本文研究了不同水分含量对微波变性的影响,发现微波辐射导致淀粉颗粒内部产生的由内向外的瞬间膨胀压力使原木薯淀粉微孔孔径进一步增大而形成大小不同孔径的爆裂孔,脐点处的爆裂孔孔径最大,微波变性时原淀粉的水分含量应当小于35 %。孔结构的改变对提高淀粉的反应活性具有重要意义,微波处理的结果为酶的作用提供了通道。