Study On Rapid Detection Of The Quality Of Melamine Tableware And The Migration Of Formaldehyde Risk Assessment

Melamine tableware security issues gradually attract the wide attention of the public because of their extensive usage. At present, there is no effective method for the rapid detection of the quality of melamine tableware. As a green and efficient analysis technology, Near Infrared Spectroscopy (NIR) shows huge potential for assessing the quality of melamine tableware rapidly and objectively. Though melamine tableware complies with the national physical and chemical index, there exists the risk for formaldehyde migrating from it into food, which results in security problem. Therefore, this research focus on the qualitative analysis of melamine tableware based on NIR technology, and the melamine tableware is made from melamine-formaldehyde resin and urea-formaldehyde+melamine-formaldehyde resin. Moreover, this research also draws the attention on the quantitative modeling prediction of the quality indicators of melamine tableware. These indicators include quality of melamine tableware, the migration concentration of formaldehyde, lightness L*and a*value. Meanwhile, the formaldehyde migration regulations under the conditions of different types of food models, temperature, time, washing, disinfection and others had been studied in detail. At last, Formaldehyde migration model to assess the security risk in the melamine tableware had been built in this paper. The conclusions have been drawn as following.1. Models for the qualitative analysis of melamine tableware made from melamine-formaldehyde resin, tableware made from urea-formaldehyde+melamine-formaldehyde resin and two batches of melamine tableware were built via using soft independent modeling of class analogy (SIMCA) and principal component analysis-discriminant analysis (PCA-DA). All of the prediction accuracy reached100%.2. The partial least square (PLS) quantitative analysis model was established for the determination of quality indicators of melamine tableware by using NIR. The optimal model for the quality of melamine tableware, the migration concentration of formaldehyde, lightness L*and a*values was made by different pretreatment and the correlation coefficient methods. The parameter of the quality of melamine tableware were Rc=0.92764, RMSECV=0.8794, Rp=0.87945, RMS EP=1.1717; the parameter of migration concentration of formaldehyde were Rc=0.96878, RMSECV=0.8794, Rp=0.95649, RMSEP=0.7541; the parameter of lightness L*were Rc=0.95069, RMSECV=0.7354, Rp=0.90355, RMSEP=1.0304; the parameter of a* values were Rc=0.96972, RMSECV=0.2043, Rp=0.90708, RMSEP=0.3527。3. The formaldehyde migration regulation of melamine tableware, which was for national physical and chemical indicators, was studied by using acetyl acetone spectrophotometer. The results indicated that there were large amounts of formaldehyde migrations under the condition of3%white vinegar and10%sucrose solution and the differences of migration amounts under the condition of3%acetic acid and3%white vinegar. In order to reduce the formaldehyde migration, the usage temperature, bloom time, re-use frequency should be strictly controlled when the melamine tableware is used. Different effects of washing and disinfection methods used in the process of melamine tableware repeatedly on the melamine tableware were provided. The migration of formaldehyde after ultrasound and detergent cleaning then treatment with84disinfectant and disinfection effervescent was lower than that of the control group. Therefore, it was suitable for cleaning melamine tableware before use it.4. A monolayer migration mathematical model (only considering the one-dimensional diffusion) for melamine tableware determination had been established based on Fick’s second law. The effect of soaking solution (3%acetic acid, distilled water,10%ethanol,0.3%citric acid and3%white vinegar) and soaking time (40℃,70℃and90℃)were discussed. The results showed that the temperature has great influence on the diffusion coefficient and partition coefficient. Diffusion coefficient of formaldehyde increases with the increasing temperature, meanwhile the partition coefficient between the melamine tableware and stimulant solutions decreases. The diffusion coefficient values of stimulant solutions showed the order of3%white vinegar>3%acetic acid>0.3%citric acid> distilled water>10%ethanol, the partition coefficient was in sequence of3%white vinegar<3%acetic acid<0.3%citric acid<distilled water<10%ethanol.5. A security risk assessment about the foods for adults in the melamine tableware had been performed. The effects of food types, washing, disinfection, migration temperature, migration time, and acetic acid concentration on the daily intake amount of formaldehyde of adults had been discussed. Meanwhile, compared with data from the U.S. Environmental Protection Agency ADI (0.2mg/Kg·bw), security risk assessment on the food intake of adults in different conditions of use melamine tableware had been performed and the appropriate recommendations had been put forward at the same time.