胶态金纳米型时间-温度指示器性能研究

目的 探究基于金纳米颗粒的时间温度指示器（Time-temperature indicator, TTI）的变色机理及不同制备参数对其动力学参数的影响，为其在食品上的实际应用提供参考依据。方法 以明胶与氯金酸的还原反应为基础制备胶态金纳米型时间-温度指示器。通过紫外-可见分光光度计对TTI的吸光度进行测定，并将其与时间进行非线性拟合。采用单因素实验探讨制备参数对反应速率、变色寿命和活化能的影响。结果 TTI体系中生成的金纳米颗粒使得TTI呈现紫红色，金纳米颗粒数量的增加导致TTI的颜色变深。明胶用量减少而明胶-氯金酸质量比不变，以及明胶用量不变而明胶-氯金酸质量比增大的情况下，TTI体系的反应速率变慢，变色寿命延长。明胶-氯金酸质量比决定了TTI体系的活化能。TTI的活化能的范围为77.89～84.58 kJ/mol。结论 TTI具有监测因脂肪氧化而变质食品的潜能，通过调节TTI的制备参数可改变其变色寿命以匹配不同货架期的食品。

Colloidal Time-temperature Indicators Based on Gold Nanoparticles

The work aims to explore the color-changing mechanism of time-temperature indicator (TTI) based on gold nanoparticles and the influence of different preparation parameters on its kinetic parameters to provide basis for its practical application in food. Colloidal TTI was prepared based on the reduction reaction of gelatin and chloroauric acid. The absorbance of TTI was measured by a UV-visible spectrophotometer, and nonlinearly fitted to time. The effects of prepa-ration parameters on the reaction rate, color lifetime and activation energy were investigated with single-factor experiments. The gold nanoparticles produced in the TTI system made the TTI appear purple, and the increase in the number of gold nanoparticles caused the color of the TTI to become darker. When the dosage of gelatin was reduced and the mass ratio of gelatin-chloroauric acid was unchanged, or when the dosage of gelatin was unchanged and the mass ratio of gela-tin-chloroauric acid was increased, the reaction rate of the TTI system slowed and the color change life prolonged. The gelatin-chloroauric acid mass ratio determined the activation energy of the TTI system. The activation energy of TTI was concentrated, ranging from 77.89 to 84.58 kJ/mol. TTI has the potential to monitor the food that are spoiled due to fat oxidation. By adjusting the preparation parameters of TTI, its color lifetime can be changed to match food with different shelf life.