Indicator films based on anthocyanins loaded on Metal-Organic Framework carriers and BP neural network for monitoring meat freshness

This study presented a novel indicator film for monitoring chicken freshness based on polyvinyl alcohol (PVA) and chitosan (CS) incorporated with a natural dye of anthocyanin loaded on MOFs (UiO-66 and UiO-66-Br) carriers. The characterization results of UiO-66/A and UiO-66-Br/A dyes showed that most anthocyanins bind to MOFs by intermolecular forces without disrupting the MOFs structure. Different dyes (anthocyanin, UiO-66/A, UiO-66-Br/A) with the same effective dye content were added into PVA/CS matrices to form PVA/CS/A (PCA) film, PVA/CS/UiO-66/A (PCUA) film and PVA/CS/UiO-66-Br/A (PCBA) film. With the addition of UiO-66/A and UiO-66-Br/A, the tensile strength and elongation at break of indicator films decreased. Small amounts of dye migration were observed in acidic and neutral food simulants for PCUA and PCBA films, while no dye migration was observed in alcoholic food simulants. PCUA and PCBA films exhibited higher sensitivity for detecting ammonia vapor, with a detection limit of 24.39 ppm for PCBA films. When all films were used to monitor changes in chicken breast freshness, PCBA films presented more accurate color changes than other films. The BP neural network-based prediction model utilizing the color change of PCBA film effectively predicted the freshness of chicken breast.