pH-responsive double-layer indicator films based on konjac glucomannan/camellia oil and carrageenan/anthocyanin/curcumin for monitoring meat freshness

Double-layer indicator film (DIF, the indicator layer made of carrageenan (CAR), curcumin (CUR) and/or anthocyanin (ATH), and the emulsified layer (named KC layer) made of konjac glucomannan (KGM) and camellia oil.) was fabricated to monitor the chicken meat freshness in this study. The three kinds of DIFs (CAR-ATH-KC, CAR-ATH-CUR-KC and CAR-CUR-KC) were tested. The results of FTIR demonstrated that different components were bound together by hydrogen bond. The double-layer structure films were clearly observed by SEM images. The presence of KC layer significantly improved the thermal stability, water- and UV-resistance performance, and mechanical properties of the indicator layer. Furthermore, Visual observation indicated that the CAR-ATH-KC and CAR-ATH-CUR-KC labels used to monitor the chicken meat freshness at 25 °C presented the more obvious color change than the CAR-CUR-KC label.