Effect of combining UV-C irradiation and vacuum sealing on the shelf life of fresh strawberries and tomatoes

The potent effect of selenium nanoparticles: insight into the antifungal activity and preservation of postharvest strawberries from gray mold diseases

BACKGROUND

Most microorganisms that cause food decay and the lower the shelf life of foods are fungi. Nanotechnologies can combat various diseases and deal with the application of nanomaterial to target cells or tissues. In this study selenium nanoparticles (Se-NPs) were synthesized using ascorbic acid and characterized by ultraviolet-visible spectroscopy, transmission electron microscopy (TEM), X-ray diffraction and zeta potential. The different concentrations of As/Se-NPs were tested against various fungi, including Alternaria linicola, Alternaria padwickii, Botrytis cinerea, Bipolaris sp., Cephalosporium acremonium, Fusarium moniliform and Fusarium semitectum. This study tested the influence of coated As/Se-NPs on healthy strawberry fruits and those infected with Botrytis cinerea during 16 days of storage, with regard to shelf life, decay percentage, weight loss, total titratable acidity percentage, total soluble solids content (TSS) and anthocyanin content.

RESULTS

Energy-dispersive X-ray analysis showed only two elements: selenium and oxygen. TEM images showed that the nanoparticles ranged in size between 26 to 39 nm and were rhombohedral in shape. Se-NPs showed antifungal activity against all tested fungi, the most effective being against Botrytis cinerea, Cephalosporium acremonium and Fusarium semitectum. During storage periods of strawberries fruits coated with As/Se-NPs, the shelf life was increased, and the number of decaying fruits was less than in control (uncoated) and coated infected fruits. The decline in weight loss was lower in coated fruits than in control fruits.

CONCLUSION

These findings demonstrated that As/Se-NPs could effectively maintain the postharvest quality of strawberries, even when the fruit was infected with B. cinerea. © 2024 Society of Chemical Industry.

Postharvest Quality Improvement of Tomato (Solanum lycopersicum L.) Fruit Using a Nanomultilayer Coating Containing Aloe vera

The effectiveness of an alginate/chitosan nanomultilayer coating without (NM) and with Aloe vera liquid fraction (NM+Av) was evaluated on the postharvest quality of tomato fruit at 20 °C and 85% relative humidity (RH) to simulate direct consumption. Both nanomultilayer coatings had comparable effects on firmness and pH values. However, the NM+Av coating significantly reduced weight loss (4.5 ± 0.2%) and molds and yeasts (3.5-4.0 log CFU g-1) compared to uncoated fruit (16.2 ± 1.2% and 8.0 ± 0.0 log CFU g-1, respectively). It notably lowered O2 consumption by 70% and a 52% decrease in CO2 production, inhibiting ethylene synthesis. Visual evaluation confirmed NM+Av's efficacy in preserving the postharvest quality of tomato. The preservation of color, indicated by the Minolta color (a*/b*) values, demonstrated NM+Av's ability to keep the light red stage compared to uncoated fruit. The favorable effects of NM+Av coating on enhancing postharvest quality indicates it as a potential alternative for large-scale tomato fruit preservation.