Calcium-alginate coating loaded with silver-montmorillonite nanoparticles to prolong the shelf-life of fresh-cut carrots

In this work, the effects of both active coating loaded with silver-montmorillonite (Ag-MMT) nanoparticles and film barrier properties on shelf life of fresh-cut carrots are presented. In particular, sensory and microbiological quality has been monitored during the storage period. While for microbiological quality the main spoilage microorganisms (mesophilic and psychrotrophic bacteria, Enterobacteriaceae spp., Pseudomonas spp., yeasts and moulds) were monitored, colour, odour, firmness and product overall quality were judged for the sensory evaluation. Results highlighted that statistically significant differences in microbial populations were found between coated and active coated samples. For the products with active coating microbial cell loads remained always below the selected microbial threshold. Moreover, samples packaged with the active coating appeared to be better preserved from a sensory point of view. As regards packaging mass transport properties, the film made up of oriented polypropylene with a thickness of 20 μm was found to be the most suitable for fresh-cut carrots. Thus, experimental results demonstrated that a significant shelf life prolongation up to more than two months can be achieved by using the developed active coating before packaging the fresh-cut carrots in a proper system.

► Coating with silver nanoparticles improves shelf life of fresh-cut carrots. ► Differences in shelf life values were found between un-coated and coated samples. ► Active samples shown cell load below the imposed threshold during the storage.