超高压处理对玉米淀粉结构及糊化特性的影响

利用光学显微、X-射线衍射、差示扫描量热、快速黏度分析技术研究了超高压处理对玉米淀粉结构及糊化性质的影响。结果显示,超高压处理能使玉米淀粉糊化,处理压力为500 MPa及600 MPa时完全糊化所需保压时间分别为15 min和5 min,但400 MPa超高压处理30 min也不会使淀粉糊化。超高压糊化过程中,淀粉颗粒结构逐渐破坏膨胀,结晶结构由A型向V型转化,RVA黏度曲线峰值黏度逐渐消失。适宜条件的超高压处理对淀粉颗粒同时具有韧化和晶体破坏作用。其中,400 MPa超高压处理5~10 min时,淀粉颗粒内部韧化作用占优,因而表现为相对结晶度、糊化温度(T_o,T_p)及糊化焓增加,而RVA曲线峰值黏度降低。

Effects of Ultra High Pressure on the Structure and Pasting Properties of Corn Starch

The effects of ultra high pressure on structure and pasting properties of corn starch were investigated by using light microscope, X-ray diffractometer, Differential Scanning Calorimeter and rapid viscosity analyzer. The results showed that ultra high pressure treatment could induce starch gelatinization. Corn starches were completely gelatinized when treated at 500 MPa for 15 min or at 600 MPa for 5 min. However, starches were not gelatinized even at 400 MPa for 30 min. During pressure-induced gelatinization, the starch granules swelled, whereas the crystal structure reflected a transformation from the A-type crystallite to the V-type crystallite. In addition, the peak viscosity in RVA viscosity curve was disappeared. Ultra high pressure treatment could result in the annealing and crystal disintegration of starch granules. The effects of ultra high pressure on starch granules were mainly based on the annealing after a pressure treatment at 400 MPa for 5-10 min, the relatively crystallinilities, gelatinization temperature(To, Tp) and enthalpy increased, while the peak viscosities decreased in RVA curves.