摘要
微波辐照水分含量为30%的普通玉米淀粉及其辛烯基琥珀酸改性后的淀粉。结果表明:随着辐照时间的延长,淀粉的水分含量均出现下降趋势,4min时两种淀粉的含水量已降至正常水平。通过扫描电子显微镜观察到两种淀粉微波辐照后,其颗粒表面出现破损,部分颗粒甚至完全破裂。而玉米淀粉及改性淀粉微波辐照前后的结晶性质都基本相似。改性前后的淀粉其糊化后都属于假塑性非牛顿流体,幂律模型对其剪切应力与剪切速率曲线的拟合精度高。随着辐照时间的延长,玉米淀粉的黏度有所降低,改性淀粉呈现先下降后上升的趋势,玉米淀粉的储能模量先增加后减小,耗能模量变化不大,损耗因子的变化趋势则与储能模量相反。而对于改性淀粉,除了辐照6min的样品,其余组的黏弹性变化甚微,该处理时间的储能模量与耗能模量都高于其他处理时间的样品,而损耗因子也出现显著降低。
Native corn starch containing 30% moisture and octenyl succinate modified starch were treated by microwave for different periods of time to investigate the effect of microwave radiation on their physico-chemical properties. The moisture content of native starch and modified starch showed a downward trend with increasing microwave radiation time and reached normal levels after 4 rain. Partial or even complete rupture on the surface of both starch granules was observed by SEM after microwave radiation. Moreover, their crystallinity basically remained stable before and after microwave radiation. Both starches and their gelatinization products were found to be pseudoplastic non-Newton fluids. Power law model could well fit shear force as a function of shear rate. The viscosity of native corn starch decreased, but octenyl succinate modified starch showed a trend to initially increase and then decrease with increasing microwave radiation time. The storage modulus of native corn starch initially increased and then decreased, and the loss modulus exhibited only minor changes, whereas an opposite changing trend to storage modulus was observed for loss factor. Octenyl succinate modified starch revealed only minor changes in viscoelasticity. For octenyl succinate modified starch, microwave radiation for a period of lower than 6 min resulted in only very minor changes in viscoelasticity when compared to control group （not receiving microwave radiation） and a decrease in storage and loss moduli but a significant increase in loss factor when compared to 6 min microwave radiation.
出处
《食品科学》
EI
CAS
CSCD
北大核心
2013年第1期121-126,共6页
Food Science
基金
湖北省农业科技创新团队资助项目
