Migration Dynamics Of Tinuvin P Of PP During Microwave Treatment

Food containers and packaging materials are closely related to food sanitation,which safe directly influence people's health.During the microwave irradiation,the low molecular weight substance(additives,residual solvents,etc.) of food materials or containers will rapidly migrate into the food,which presents the threat towards human,under the heating time,power,microwave distribution,contact area and many other factors.Studying the migration theoretically and experimentally of the chemicals from the plastic packaging materials into food and revealing the mechanism and dynamics of migration under microwave irradiation are of great engineering and academic importance.The dynamic behaviour of migration of UV absorber Tinvuin P from PP film into the fatty food simulant(olive,peanut or soybean oil) was studied.The input power of the microwave was 100W,250W,600W,900W respectively.The dependence of the temperature of simulant on time was monitored real time by using optical fibre temperature detecting system.The amounts of Tinvuin P migrating into the above three simulants under different input powers were determined by high performance liquid chromatography(HPLC).The loss of Tinvuin P under the same condition was determined as well.The result showed that the species of the fatty simulants had little effect on the amounts of both migration and loss while the input power and time duration had significant effect on them.Especially when the temperature arrived at 120℃under the input power of 100W in 850s,the loss of Tinuvin P reached 30%.So the loss should be considered so as to avoid the underestimate of the real migration amount.Diffusion coefficient model was obtained based on the Brandsch semi-empirical formulary of diffusion coefficient.In the Brandsch model,the temperature T was substituted by the absorption power P and time t.For the finite packaging-infinite food system,when the initial and boundary conditions were given and loss coefficient was introduced with diffusion coefficients varying,the dynamic expression was solved to obtain the migration amount.The experimental data and the data predicted by the model were compared and the model was evaluated.The result showed that the model could well predict migration trend,although it overestimated the migration amount.