开发了一种最适合速冻鲜食玉米的保温包装形式，以延长速冻鲜食玉米保温包装的保温时间。通过热线法研究了保温绝热材料模塑聚苯乙烯（EPS）、挤塑聚苯乙烯（XPS）和硬质聚氨酯（PU）三种材料的密度和不同环境温度对材料导热系数的影响，并通过单因素试验，研究了保温箱厚度和蓄冷剂与速冻鲜食玉米的质量比对XPS保温箱保温性能的影响。结果表明：导热系数先随密度的增大而减小，然后随密度的增大而增大；随着环境温度的升高，导热系数呈增大趋势，但是不同材料受温度的影响程度不同；随着厚度的增大，XPS保温箱的保温性能逐渐增强，当厚度大于30 mm时，对保温效果的影响明显变大；随着蓄冷剂与速冻鲜食玉米质量比的增大，保温箱中心位置的保温时间呈现先增大后下降的趋势。在23 ℃/50%环境条件下，40 mm厚XPS保温箱内蓄冷剂与速冻鲜食玉米的质量比为5:8时，速冻鲜食玉米的保温时间能够有效达到36 h以上。

This study developed a suitable box for insulation packaging of quick-frozen fresh corn to prolong its thermal insulation period. The effects of the densities of molded polystyrene (EPS), extruded polystyrene (XPS), and rigid polyurethane (PU) and of environmental temperature on the coefficient of thermal conductivity by using hot-wire method were examined. In addition, the effects of the thickness of the insulation box and mass ratio of coolant and quick-frozen fresh corn on the thermal insulation efficiency of XPS insulation-packaging box were investigated. The results showed that thermal conductivity decreased with an increase in density and increased with an increase in environmental temperature. However, environmental temperature exerted different effects on different materials used for developing the insulation-packaging box. Thermal insulation efficiency of the XPS thermal insulation-packaging box gradually improved with an increase in its thickness. Thermal insulation-packaging box having a thickness of >30 mm showed significantly increased thermal insulation efficiency. However, an increase in the mass ratio of the coolant and quick-frozen fresh corn decreased the thermal insulation period at the center of the insulation box after an initial increase. Thermal insulation period of quick-frozen fresh corn in a 40-mm XPS thermal insulation-packaging box can be effectively extended to >36 hours by maintaining the temperature at 23 ℃, humidity at 50%, and mass ratio of the coolant and quick-frozen fresh corn at 5:8.

“十二五”国家科技支撑计划项目（2015BAD16B05）；天津市科技攻关计划项目（06YFGPNC03400）；天津市应用基础及前沿技术研究计划（13JCZDJC30900），天津食品安全低碳制造协同创新中心资助