浸渍冷冻载冷剂的冻结点分布与渗透性

对于乙醇、丙二醇、盐类与水构成的三元以及四元载冷剂,采用温度-时间法,研究其组成与冻结点的关系,采用硝酸银滴定法和气相色谱法,研究多元载冷剂对食品明胶模型的渗透作用.结果表明,溶质质量分数大于45%的乙醇、丙二醇与水组成的三元载冷剂的冻结点比同质量分数的乙醇水溶液低,乙醇质量分数为20%~30%时,溶液的冻结点达到最低值;盐类中的NaCl对四元载冷剂冻结点下降的影响最明显;与常用的盐水及乙醇水溶液相比,乙醇、丙二醇、NaCl与水构成的四元载冷剂向冻结明胶模型的溶质渗透量最小;乙醇、丙二醇、NaCl与水构成的四元载冷剂具有冻结点低、溶质质量分数小、渗透量小等优点,更适合作为浸渍冷冻载冷剂.

Freezing Point Distribution and Impregnation Capacity of Refrigerant Liquids for Immersion Chilling and Freezing

To select refrigerant liquids involved in the food immersion chilling and freezing technology, researches on the changing characteristics of freezing points and impregnation in gelatin gel model at low temperature of different refrigerant liquids ,composed of ethanol ,propylene glycol ,salt and water, had been conducted. Results indicated that the freezing points of ternary solutions composed of ethanol ,propylene glycol and water reached the lowest value when the glycol content reaches 20~30%.The freezing points dropped obviously when sodium chloride or calcium chloride was added . Compared with common salt solution or ethanol solution, the solute impregnation of quaternionic solutions composed of ethanol ,propylene glycol, sodium chloride or calcium chloride, and water in gelatin gel model was fewer than formal aqueous solution at the same temperature.