Objective To develop a sensitive and stable dual signal output indicator label and realize real-time monitoring of the freshness of Litopenaeus vannamei. Methods Based on polyvinyl alcohol (PVA)/agar composite matrix combining anthocyanins (ACNs), silver coated gold nanoparticles (Au@AgNPs) and the metal organic framework material UiO-66, the dual signal output indicator labels were prepared by casting method. Next, the stabilizing effect of UiO-66 on the labels was investigated by storage stability, ultraviolet stability and anti-migration experiments. Ammonia, dimethylamine and trimethylamine were used as characteristic volatile markers to evaluate the gas sensitive response performance of the labels. Ultimately, the label was applied to real-time monitoring of the freshness of Litopenaeus vannamei. Results Compared to labels without UiO-66, the addition of UiO-66 effectively immobilized the anthocyanins and improved the UV stability and storage stability of the label. In addition, the label showed excellent responsiveness to ammonia and amine gases. In the application of freshness monitoring of Litopenaeus vannamei, the color of the indicator label gradually changed from purplish-red to bluish-green with the change of freshness of Litopenaeus vannamei. The partial least squares regression (PLSR) model based on the surface-enhanced Raman scattering (SERS) signals showed excellent prediction performance for the total volatile basic nitrogen (TVB-N) values, with a correction set coefficient of calibrated coefficient of determination (R2C) of 0.951, cross-validated coefficient of determination (R2CV) of 0.899, predicted coefficient of determination (R2P) of 0.966, and residual prediction deviation (RPD) of 4.765. Conclusion A colorimetric-SERS dual-signal output indicator label is developed in this study. The label enable simultaneous visual identification of the freshness of Litopenaeus vannamei and high-sensitivity prediction of TVB-N values, providing a reference for the design of novel intelligent food packaging systems.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |