碾轧对绿豆淀粉的机械力化学效应

以绿豆淀粉为原料,通过扫描电镜(SEM)、偏光显微镜(PLM)、激光扫描共聚焦显微镜(CLSM)、X-射线衍射(XRD)、差示扫描量热仪(DSC)、快速黏度分析仪(RVA)等手段研究碾轧处理对淀粉结构和性质影响,探究其相互关系并揭示碾轧对绿豆淀粉机械力化学效应。结果表明,碾轧处理3~6 h时,淀粉无定型区和部分结晶区发生破坏,水溶指数、膨胀度、透光率增大,热焓减小。碾轧处理9 h时,淀粉内部发生重结晶,颗粒表面形成球状凸起,脐点区域直链淀粉聚集导致膨胀度、透光率、峰值黏度下降,水溶指数、热焓值、糊化温度增大。碾轧处理12~24 h时,淀粉的结晶区域发生显著破坏,颗粒严重变形,从而使淀粉水溶指数、透光率增大,膨胀度、热焓值减小。根据机械力化学相关理论推断淀粉颗粒内部依次经过了受力阶段、聚集阶段、团聚阶段。

Mechanochemical Effect of Rolling on Mung Bean Starch

Using mung bean starch as raw materials, the effect of rolling on structure and physicochemical properties of mung bean starch was investigated by scanning electron microscope (SEM), polarizing microscope (PLM), confocal laser scanning microscope (CLSM), X-ray diffraction (XRD), differential scanning calorimeter (DSC), and rapid visco analyser (RVA). The mechanochemical effect of milling on mung bean starch was revealed. The results showed that the amorphous and part of the crystalline regions of mung bean starch was destroyed by rolling treatment 3~6 h, which led to the increase of water solution index, welling power, transparency and a significant reduction of gelatinization enthalpy. With the increasing of processing time, recrystallization was happened inside starch granules. At the same time, some bulbous protuberances had formed on the granule surface. And welling power, transparency, peak viscosity presented a significant decrease. Furthermore, water solution index, enthalpy and gelatinization temperature of the mung bean starch increased. As the rolling processing time increased to 12 and 24 h, crystal structure had been severely damaged. Meanwhile, the particle morphology of starch underwent serious change in accompany with water solution index and transparency was increased. But opposite trends were found in enthalpy and welling power. According to the theory of mechanochemistry, loading, aggregation and agglomeration effects occurred successively in the interior of starch granules.