Sensitive detection of meat spoilage VOCs and visual monitoring of freshness via a UiO-66-NH 2 @MR nanocomposite-based colorimetric paper sensor

of 0.9446 and 0.9245, respectively. The proposed UNMPS exhibits high sensitivity, satisfactory repeatability, reproducibility, and stability. Hierarchical cluster and principal component analysis further confirm its reliability for real-time monitoring of meat freshness. Overall, UNMPS provides a convenient and efficient visual platform for food freshness assessment.