A colorimetric hydrogen sulfide (H2S) 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 H2S to form Ag2S. The sensor enables the analysis of H2S with a limit of detection (LOD) of 0.81 μM, and it exhibited excellent selectivity toward H2S 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 H2S 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.

Nanoparticles with unique properties have potential applications in food, medicine, pharmacology, and agriculture industries. Accordingly, many significant researches have been conducted to develop novel nanoparticles using chemical and biological techniques. This review focuses on the synthesis of selenium nanoparticles (SeNPs) using polysaccharides as templates. Various instrumental techniques being used to confirm the formation of polysaccharide-SeNPs conjugates and characterize the properties of nanoparticles are also introduced. Finally, the biological activities of the synthesized SeNPs and the influence of structural factors of polysaccharides on the property of synthetic nanocomposites are highlighted. In general, the polysaccharides functionalized SeNPs can be easily obtained using sodium selenite as precursor and ascorbic acid as reductant. The final products having different particle size, morphology, and selenium content exhibit abundant physiological activities. Structural factors of polysacchairdes involving molecular weights, substitution of functional groups, and chain conformation play determinant roles on the properties of nanocomposites, resulting in different biological performances. The review on the achievements and current status of polysaccharides conjugated SeNPs provides insights into this exciting research topic for further studies in the future.