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With the gradual improvement of the quality of life, more and more people on food security requirements. The expiration date is an important aspect of food safety, and the influence of temperature on the shelf life of the crucial. For those affected by temperature, especially for the larger food. So, as described on the label outside of the package shelf life (or valid), but can be stored in a certain set of conditions, and the actual storage and use, does not guarantee that the food is not placed in the other environmental conditions (such as high temperature). In this way, product shelf life has become an open question. Therefore, in order to ensure the safety of food, time temperature indicator TTI (time Temperature Indicator) came into being, according to the temperature changes of time, it can simulate the deterioration of the food process, indicating the degree of safety of the food. The common foreign markets TTI enzymes, diffusion, chemical, and electronic type. TTI has been used to monitor the quality of the meat, milk, mushrooms, blood and other perishable products in some areas also used in logistics and high-temperature sterilization detection. Of TTI research is still in the early stages of research and development. The main subject of the use of alkaline lipase reaction developed a time-temperature indicator (TTI), the indicator of the structure, dynamics parameters, based on the application of certain research. Of this research include: (1) was developed based on the alkaline lipase reaction time temperature indicator, the time-temperature indicator by the degree of response of the color ring indicator of the size of the judgment. Issues by comparing the test 0.5% neutral red as the indicator of the indicator. The same time, the scope of application of the formulation process is determined by orthogonal test, control the use of agar in the the 0.01g/ml ~ 0.015g/ml between the substrate buffer proportional control at around 4.5%, lipase enzyme concentration according to The proportion of substrate buffer adjusted accordingly, the general choice 0.02g/ml. Agar plates select diameter of 11mm, and a thickness set at 3mm. (2) of the subject based on the reaction mechanism of the time-temperature indicator designed the structure of the two types of time-temperature indicator: flat temperature indicator and vertical time temperature indicator. The two structures time temperature indicator responsive, easy to use, easy to activate and storage. (3) This issue through orthogonal test, the dynamic characteristics of nine different formulations of the time-temperature indicator. Come to the time of the temperature indicator the activation energy 30kJ/mol to 100kJ/mol between. SAS stepwise regression analysis the substrate buffer ratio, the amount of agar, enzyme concentration, the amount of enzyme solution the activation energy of the TTI degree of influence and the establishment of a model. In addition, the subject of further study on the TTI the time - temperature - the relationship between the response values, studies show that the response of the indicator value and the elapsed time and temperature have a good correlation, and establish a model of the basic relationship between the three. (4) This issue through the study of milk modification mechanism and kinetic parameters, the activation energy of the milk designed five kinds of TTI TTI and five were isothermal test, analysis of their kinetic parameters, and in conditions such as temperature stability. In addition, the subject through the variable-temperature test, the milk and the TTI in a certain time - temperature after the matching conditions, the studies show that the formulation: TTI2 (substrate buffer ratio of 4.5%, the amount of agar 0.014g/ml enzyme solution concentration 0.05g/ml, the amount of enzyme solution 0.10ml most suitable time-temperature indicator for milk.
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