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An intelligent film for the visual monitoring of pork freshness was developed using degradable polyvinyl alcohol (PVA)/starch (PS) to immobilize the chromogenic agent of anthocyanins and the volatile amine collector of metal-organic frameworks (MOFs). The indicative property of grape skin anthocyanins (GSAs) was verified using the UV-vis spectra, corresponding to multi-color changing in a pH range of 2-12. Interestingly, the introduction of MIL-101 crystals in the PS/GSAs film significantly increased the specific surface area (approximately 10 times) of the film, the superior volatile amine enrichment capability of MIL-101 enabling the film to detect freshness with a high degree of sensitivity. Moreover, the as-prepared film exhibited good antibacterial properties attributed to MIL-101, which help maintain the freshness of the pork. Owing to these advantages, the PS-GSAs/MIL-101 film was tested to real-timely monitor pork freshness in package, the results were further confirmed basis the total volatile basic nitrogen values.

The peroxide value (PV) is an important indicator to assess quality of edible oils. However, traditional methods for determining PV are complicated for operating and lack sensitivity. In this paper, we report a fast, reusable, selective and sensitive room-temperature phosphorescence (RTP)-based sensor to determine the PV of edible oils. The sensor comprises a lead-based metal-organic framework (Pb-MOF, Pb

In this study, electron spin resonance (ESR) and Raman spectroscopy were applied to characterize lipid oxidation of beef during repeated freeze-thaw (RFT). Besides the conventional indexes including peroxide values (PV), thiobarbituric acid-reactive substances (TBARS) and acid values (AV) were evaluated, the radical and molecular structure changes were also measured by ESR and Raman spectroscopy. The results showed that PV, TBARS and AV were increased (P