Gum arabic/guar gum based biopolymeric nanohydrogel for shelf-life enhancement of grapes and photocatalytic dye reduction

Recently, natural food preservation systems composed of metal oxide nanoparticles (NPs) gained great attention from the food manufacturers, however, toxicity of NPs is a major concern. Therefore, in this study we synthesized multifunctional gum arabic/guar gum biopolymeric nanohydrogel embedded with NPs for the enhancement of the shelf-life of the grapes and for photocatalytic dye reduction. Copper, zinc, and iron metal oxide NPs were tailored using chemical precipitation and co-precipitation methods and subjected to various characterization processes. The smaller particle size was observed with iron oxide NPs (23.64 nm) as compared to other NPs (Cu and Zn). All metal oxide NPs showed cell viability ranging from 90.73 - 99.94%. The average droplet size of the formulated hydrogel samples was ranging from 240.6 to 345.8 nm with an irregular and rough morphology. Nanohydrogels at varied concentrations embedded with metal oxide NPs showed cell viability in the range of 93.73-99.97%. Zinc metal oxide NPs embedded in hydrogel showed higher spreadability properties, while hydrogel embedded with iron oxide NPs showed lower spreadability properties. Grapes coated with formulated hydrogel did not affect the physicochemical attributes during the storage (10 days), hence it can be scaled up as an effective natural preservation system.

Automated summary

Recently, the use of metal oxide nanoparticles in natural food preservation systems has gained attention, but concerns about their toxicity remained. In this study, a biopolymeric nanohydrogel embedded with metal oxide nanoparticles was synthesized to extend the shelf-life of grapes and reduce dye concentration. Different methods were used to tailor copper, zinc, and iron metal oxide nanoparticles, with iron oxide nanoparticles having the smallest particle size. All metal oxide nanoparticles showed good cell viability. The formulated nanohydrogels with embedded nanoparticles exhibited varying cell viability and spreadability properties, with zinc oxide nanoparticles showing better spreadability. Coating grapes with the formulated hydrogel did not affect their physicochemical attributes during storage, making it a promising natural preservation system.