An electrospun sensing label based on poly (vinyl alcohol)-Ag-grape seed anthocyanidin nanofibers for smart, real-time meat freshness monitoring

In this study, an intelligent sensing label was developed with poly (vinyl alcohol)-Ag (PVA-Ag) nano-colloids as the carrier polymers and grape seed anthocyanidin (GSA) as indicators for the assessment of meat freshness. The colorimetric response, morphology and stability of PVA-Ag-GSA sensing label were investigated by UV-vis spectra, scanning electron microscope (SEM), thermal properties, mechanical property and hydrophilicity studies, etc. Moreover, the sensing label showed visible changes from red to yellow when employed to monitor the freshness of pork. Concerning the difficulty in distinguishing the approximate colors obtained from the sensing label, quantitative evaluation was implemented by Red-Green-Blue (RGB) and Hue Saturation Value (HSV) model. Hue (H) values showed a linear response to the total volatile basic nitrogen (TVB-N) concentration in the range of 13.1–31.1 mg/100 g during storage of 4 °C, and in the range of 12.1–30.6 mg/100 g at 10 °C. On this basis, the values calculated from the linear regression equation were in good agreement with those obtained from the contents of TVB-N measured by acid-base titration, confirming applicability of the sensing label. These results showed that the prepared sensing label could be applied in real-time freshness monitoring with satisfaction and efficiency.