Application of chitosan, zinc oxide nanoparticles, and Aloe vera gel edible coating for the extension in shelf life of tomatoes

The current research focused on the preparation and application of a nanoemulsion based edible coatings of chitosan (CH), Aloe vera gel (AVG), and ZnO nanoparticles (ZnO-NPs). Three nanoemulsion coatings, i.e., C₁, C₂, and C₃, were prepared, and one of them (C₃) was employed to observe the shelf life and other quality parameters of tomato fruits during the storage period of 20 days at a temperature of 20 ºC. The nanoemulsion coatings were prepared using different concentrations of CH, AVG, and chemically synthesized ZnO-NPs. The zeta sizer and zeta potential of C₃ nanoemulsion coating were 178 nm and −89.2 mV, respectively. The X-ray diffraction analysis revealed broad peaks at 2θ = 16.5 and 21.5°, indicating the amorphous structure of C₃ nanoemulsion coating. The SEM analysis revealed homogenous particle distribution morphology of nanoemulsion coating (C₃). The tomato samples coated with CH/AVG/ZnO-NPs-based nanoemulsion coating revealed good physiochemical results such as reduced weight (7 %) and decay percentages (18.20 %) and maintained TA (0.5 %) and TSS (3.5 %) contents. The ethylene production and respiration rates were also lower compared to the control tomato samples. Furthermore, the firmness level (8 N) and overall acceptability score (6.50) were significantly (p < 0.05) higher in coated tomato samples. The results of the present work emphasized its potential feasibility for practical use in food industrial applications.