鲢鱼糜与淀粉复合系统的微波糊化特性

在2 450 MHz频率的微波处理条件下,为了考察添加鲢鱼糜对小麦粉面团糊化的影响,将小麦粉、鲢鱼糜、NaCl和去离子水按比例混合制成鲢鱼糜面团,面团中鲢鱼糜含量分别为0%,10%,20%和30%(w/w,质量百分比),对样品面团中淀粉的介电特性和糊化特性进行研究。结果表明,对于相同尺寸的面团样品,添加鲢鱼糜可改善面团样品在电磁场中的加热均匀性。随着温度的升高,面团的介电常数和介电损失率分别在20~23和9~12内波动并呈下降趋势,微波的穿透深度因淀粉的糊化略有上升。淀粉的糊化速率随温度的升高而下降。降低样品中淀粉的含量,会使面团糊化活化能由113.54 kJ/mol下降至59.96 kJ/mol。

Study of the gelatinization properties of mixtures composed of sliver carp surimi and wheat flour during microwave heating

The aim of this work was to study the effect of adding silver carp surimi on dielectric properties and gelatinization characteristics of wheat flour heated by 150 W microwave oven operating at 2 450 MHz. Wheat flour and silver carp surimi were mixed in various proportions (10:0, 9:1, 8:2, and 7:3) at moisture content of 38 wt.% with 2 wt.% salt. Then, the mixtures were formed to three different sizes and two different shapes to investigate the effect of geometry on uniformity of temperature distribution under microwave heating. The dielectric properties of silver carp surimi-wheat flour dough were detected by the open-endedcoaxial probe method. Differential scanning calorimeter (DSC) was conducted to determine the extent of gelatinization of wheat starch. It is observed that the uniformity of temperature distribution for cylindrical-shaped pieces of dough was better than cuboid ones and the smaller ones were better than bigger ones. When temperature increased, the dielectric constants and loss factors of all dough tend to decrease. As silver carp surimi was added, the uniformity of temperature distribution was improved, however, the activation energy of sample decreased. The gelatinization rate of starch decreased with temperature rise and addition of silver carp surimi as a result of interaction of surimi and water.