多元纳米相变蓄冷剂的制备及食用菌保鲜应用

Development of multi-nano phase change cold storage material and its application in edible fungi preservation

为了探究无机纳米粒子对有机相变纳米流体热物性的影响,该文以甘露醇水溶液为主储能剂,添加不同质量分数的二氧化钛纳米粒子,并以高吸水性树脂(super absorbent polymer,SAP)为载体制备凝胶态二氧化钛相变蓄冷剂。采用差示扫描量热法测定蓄冷剂的相变温度和相变潜热,并通过温度-时间曲线,反复冻融实验测定其性能,应用于双孢蘑菇的保鲜并对保鲜效果进行评价。结果表明,纳米二氧化钛对纳米流体的相变潜热具有增强作用,0.01%(质量分数)为最佳添加量,该质量分数下研制的蓄冷剂(甘露醇0.5%,纳米二氧化钛0.01%,SAP 0.3%,均为质量分数,其余为水)相变温度为-0.45℃,相变潜热为303.01 J/g,无过冷和相分离现象。应用于双孢蘑菇的保鲜中,可有效地将泡沫箱内温度控制在0~5℃,且长达35 h,说明研发型二氧化钛相变蓄冷剂具有很好的蓄冷能力。在室温条件(22℃)下,泡沫箱内添加自制蓄冷剂可以更好地保持双孢蘑菇的色泽、硬度、可溶性固形物和细胞膜通透性,减少质量损失,延缓双孢蘑菇的衰老。

In order to explore the influence of inorganic nanoparticles on the thermal properties of organic phase change nanofluids,mannitol aqueous solution was chosen as the main energy storage agent,added titanium dioxide nanoparticle with different mass fractions,and prepared TiO_(2)phase change cold storage material with super absorbent polymer(SAP)as the carrier.The oneset temperature and phase change enthalpy of the PCMs were measured by differential scanning calorimeter,and its properties were tested by a T-t curve and freeze-thaw cycles.Furthermore,the PCMs were applied to the preservation of Agaricus bisporus.The results showed that the addition of titanium dioxide nanoparticles enhanced the phase change enthalpy of nanofluid and the best additive amount was 0.01%.The developed PCMs(mannitol 0.5%,titanium dioxide nanoparticle 0.01%,SAP 0.3%,the rest was water)had an oneset temperature of-0.45℃,phase change enthalpy of 303.01 J/g with no supercooling or phase separation phenomenon.In the Agaricus bisporus preservation application,the addition of the developed PCMs in foam boxes could effectively control the temperature of 0-5℃for up to 35 h.It indicated that the developed PCMs of TiO_(2)phase change storage material had good cool storage capacity.At 22℃,the color,the weight loss rate,the hardness,the soluble solids and the membrane permeability of Agaricus bisporus could be better maintained,and the senescence of Agaricus bisporus could be delayed.