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• Ag nanoparticles (AgNPs) were green synthesized by using gellan gum (GG). • GG-AgNPs show good sensitivity and selectivity towards H 2 S. • GG-AgNPs presented visible color changes when used to monitor meat spoilage. • GG-AgNPs should have great potential for application in intelligent packaging. A colorimetric hydrogen sulfide (H 2 S) sensor based on gellan gum capped silver nanoparticles was developed to real-time monitor meat spoilage. The colorimetric sensor strategy was attributed to the ultrastrong binding ability of Ag with H 2 S to form Ag 2 S. The sensor enables the analysis of H 2 S with a limit of detection (LOD) of 0.81 μM, and it exhibited excellent selectivity toward H 2 S against other volatile components generated from chicken breast and silver carp during spoilage. By these virtues, the sensor presented visible color changes from yellow to colorless by in situ and nondestructively sensing H 2 S generated from chicken breast and silver carp in a packaging system. This strategy provided a simple but useful, non-destructive, robust, cost-effective, and user-friendly platform to real time monitor meat spoilage for intelligent food packaging. [ABSTRACT FROM AUTHOR]

[Display omitted] • Gelatin/gellan gum bilayer film was prepared as a novel probiotic carrier material. • Blueberry anthocyanin extract (BE) improved the probiotic viability in the film. • Baobab seed oil (BO) improved water and oxygen barrier properties of the stored film. • BO/BE loaded-bilayer film obtained the greatest Bifidobacterium longum viability. • BO/BE loaded-bilayer film maintain satisfactory B. longum viability in steamed bread. The gelatin/gellan gum based-bilayer emulsion film was developed in this work to improve the survivability of Bifidobacterium longum during the storage process. The baobab seed oil (BO) was added to the gelatin (GE) matrix to develop emulsion film as the barrier outer layer. The blueberry anthocyanin extract (BE) was incorporated into the gellan gum (GG)-based inner layer to enhance the viability of B. longum. The SEM and FTIR results revealed that the probiotics were successfully entrapped in BO/BE-loaded bilayer film. The greatest survivability and viable cell numbers of the B. longum during the storage period were observed in the BO/BE loaded bilayer film. Furthermore, the stability of the colorful patterns by electrochemical writing was also evaluated in this work. Finally, the GE/BO-GG/BE/BM maintain satisfactory probiotic viability in steamed bread coating application. Hence, the GE/BO-GG/BE/BM bilayer film could be considered a novel material to deliver and protect the probiotics in food applications. [ABSTRACT FROM AUTHOR]

A novel probiotic film based on gellan gum (GN), cranberry extract (CE), and Lactococcus lactis (LA) was developed in the present study. The fluorescence and SEM image results showed that GN/CE film containing LA was successfully fabricated. The incorporation of LA significantly enhanced the antibacterial activity of the film. The presence of CE strengthened the antioxidant activity and LA survivability in the film. The combination of LA (0–1.0 %) and CE (0.5–1.0 %) improved the mechanical property of the film through the formation of density structure. The best comprehensive properties were obtained with the film containing 2.0 %LA and 0.5 %CE. The GN/2.0 %LA/0.5 %CE film also showed the optimal preservation effect on fresh-cut potatoes and apples. Hence, GN/2.0 %LA/0.5 %CE probiotic film has proved to be suitable for fruit and vegetable preservation. [Display omitted] • A novel probiotic film was prepared from gellan gum (GN)/cranberry extract/ L. lactis. • L. lactis (LA) enhanced the antibacterial activity of the film. • Cranberry extract (CE) improved the antioxidant activity and LA viability of the film. • The GN/2.0 %LA/0.5 %CE films can improve the quality of fresh-cut potatoes and apples. [ABSTRACT FROM AUTHOR]

• ZnO nanoparticles improved the UV-blocking property and color stability of the bilayer film. • Different patterns could be printed on the bilayer colorimetric film by electrochemical writing. • The bilayer colorimetric film showed a limit of detection of 0.01 mM to NH 3. • The bilayer colorimetric film with written patterns can monitor crucian freshness in real-time. Bilayer colorimetric films were developed for monitoring fish spoilage by using gelatin (GN) incorporated with ZnO nanoparticles as the upper layer (GN-ZnO), and gellan gum (GG) incorporated with mulberry anthocyanins (MBA) as the lower layer (GG-MBA). The color stability of the bilayer colorimetric films under visible and ultraviolet light was improved with the increase of ZnO nanoparticles content. Meanwhile, the bilayer films had good NH 3 sensitivity. The limit of detection of the GG-MBA/GN-2.0% ZnO film to NH 3 was 0.01 mM. The electrochemical writing ability of the bilayer films was also identified, indicating the feasibility of inks-free printing on biopolymer films. Finally, the GG-MBA/GN-2.0% ZnO film with an electrochemical writing pattern was used to monitor crucian spoilage. The GG-MBA/GN-2.0% ZnO film with electrochemical writing pattern showed visible color changes with the crucian spoilage. In conclusion, the bilayer colorimetric film was expected to be a good fish spoilage indicator in smart packaging. [ABSTRACT FROM AUTHOR]