pH-Responsive Bacterial Nanocellulose Smart Labels Derived from Acid Whey for Estimating Beef Mince Quality Alterations During Storage.

This study develops a pH-responsive label by incorporating anthocyanin from into a bacterial nanocellulose (BNC) film derived from acid whey fermentation. The labels were designed to display two distinct colors-pink and purple-by adjusting the pH of anthocyanin and were integrated into beef mince packaging to monitor quality changes over a 15-day storage period at 4 °C. Color variations were assessed using a chroma meter and visual inspection, with both label types exhibiting a shift to blue in response to a deterioration in freshness. Significant differences ( < 0.05) in total color difference (∆E) were observed across data collection days. The pink label showed an ∆E of 14.19 between day 0 and day 8, increasing to 27.39 by day 15. The purple label exhibited an ∆E of 12.94 by day 8 and 27.86 by day 15. A Total Volatile Basic Nitrogen (TVBN) analysis and microbial evaluations confirmed a degradation in the quality of the beef mince, with strong correlations between ∆E and ∆TVBN (r = 0.956 for pink, r = 0.993 for purple). Additionally, good correlations were recorded between label total color differences and coliform counts (r = 0.933 for pink, r = 0.875 for purple), as well as Total Plate Counts (TPCs) (r = 0.982 for pink, r = 0.950 for purple). These results highlight the potential of acid whey-derived nanocellulose films as real-time quality indicators for intelligent food packaging systems.