【摘要】 金属有机骨架材料（MOFs）是一类高比表面积、结构多样性、可修饰性较强的无机配位多孔骨架材料，在挥发性有机化合物的吸附、传感等领域有巨大应用前景。新鲜度的评价对于肉类工业发展具有重要意义，肉类在品质劣变时会产生挥发性物质，是指示其新鲜度变化的灵敏的信息。据此，研究制备了一种基于荧光传感的冷鲜猪肉新鲜度指示MOFs复合膜，并且依据膜对劣变挥发性化合物的响应信息、对应猪肉样品的新鲜度指标（TVB-N值）建立PLS定量分析模型，证实其有望成为冷鲜肉品质劣变监测的新技术。主要结论如下：以六水硝酸锌∶对苯二甲酸=2∶1的比例，并向其中添加浓度为2×10^-3 mol·L^-1的罗丹明B,制备得到RhB@MOF-5,并对其进行表征。根据RhB@MOF-5吸附冷鲜猪肉劣变气味前后的红外光谱变化，推测其中可能有胺类物质。之后以MOF∶PVDF（w/w）=4∶5的比例按照混合基质法制得MOFs复合薄膜。并通过贮藏期实验验证了MOFs复合膜的贮藏稳定性，证明其能在4℃避光环境中维持至少60 d的荧光稳定性。此外，利用MOFs复合膜结合荧光传感技术对冷鲜猪肉整个劣变期间的挥发性化合物进行吸附、响应，观察其荧光性质的变化。同时采用三维荧光技术观察到吸附后MOF-5相关峰和罗丹明B相关峰强度减弱，分析是由胺类物质引起的罗丹明B电子云改变，从而产生荧光猝灭。采集激发波长340 nm处的表面荧光光谱可同时得到两个发射波长分别为435nm和550nm的特征峰与TVB-N值的响应信息，使用偏最小二乘算法（PLS）建立新鲜度指标（TVB-N）预测模型，建模结果R_c²为0.908,R_p²为0.821, RMSEC和RMSEP分别为3.435和3.647 mg·（100 g）^-1,具有良好的预测精度。表明功能化MOFs复合膜可用于冷鲜猪肉的新鲜度预测。更多还原

【Abstract】 Metal Organic Frameworks（MOFs） are a kind of inorganic coordination porous framework materials with high specific surface area, and diverse and flexible structures. It has great application prospects in volatile organic compounds adsorption, sensing, etc. The evaluation of freshness is of great importance to the development of the meat industry. When meat deteriorates, the volatile substances will be produced, which is sensitive to changes in the freshness of meat. Therefore, this study prepared a kind of MOFs composite film based on fluorescence spectra to indicate thefreshness of chilled pork. Then a PLS quantitative analysis model was established according to the response information of the membrane to deteriorating volatile compounds and the freshness index of corresponding pork samples（TVB-N value）. It is proved to be a new technology for monitoring the quality deterioration of chilled meat. The main conclusions are as follows: with the ratio of zinc nitrate hexahydrate∶terephthalic acid=2∶1, and a concentration of 2×10^-3 mol·L^-1 Rhodamine B is added, RhB@MOF-5 is prepared and then characterized. According to the infrared spectra change of RhB@MOF-5 before and after adsorbing the stale smell of chilled pork, amines might be absorbed into it during meat deterioration. After wards, MOF composite film was prepared with the ratio of MOF∶PVDF（w/w）=4∶5 according to the mixed matrix method. The storage experiment showed that MOFs composite films could stabilise and maintain the fluorescence intensity for at least 60 days in a 4 ℃ dark environment. In addition, the MOFs composite membrane combined with fluorescence sensing technology was used to adsorb and respond to volatile compounds during the entire deterioration period of chilled pork, and we observed the changes in its fluorescence properties. At the same time, three-dimensional fluorescence technology was used to observe that the intensity of MOF-5 and Rhodamine B correlation peaks were weakened after adsorption. It is because the Rhodamine B electron cloud changes caused by amines, resulting in fluorescence quenching. Collecting the surface fluorescence spectra at the excitation wavelength of 340 nm, the response information of two characteristic peaks with emission wavelengths of 435 and 550 nm and TVB-N value can be obtained simultaneously. A freshness index indication model of TVB-N was established by PLS combined with surface fluorescence spectraat the excitation wavelength of 340 nm. R_c², R_p², RMSEC and RMSEP were 0.908, 0.821, 3.435 and 3.647 mg·（100 g）^-1 respectively, showing the model’s good prediction accuracy. The results showed that the functional MOFs composite films could be used to predict the freshness of chilled pork.更多还原