Nanocarriers and Curcumin in Blueberry Shelf-Life Management: <i>In Vitro</i> Preliminary Antibacterial Effect

Blueberries are very perishable, with fungi and bacteria affecting their spoilage along all the supply chain. No studies considered up to now the application of curcumin-loaded nanobubbles (NBs) or curcumin nanocrystals (NCs) to maintain their freshness. The aim of this preliminary work was to evaluate these two nanoformulations in terms of their in vitro antimicrobial effect against blueberry bacterial microbiota and establishing a quick-answer protocol in vitro in Petri plates. The effect was tested under three different light conditions (dark environment, blue LED and white LED). Results show that the presence of a lighting step (blue LED or white LED) after the microorganisms have been in contact with NBs and NCs was fundamental to activate the nanostructure and obtain a positive answer as inhibition halo. Notably, in relation to NBs, blue light significantly increased the antimicrobial potential compared to white LED; moreover, a curcumin concentration-dependent effect was highlighted (50 µg/mL with respect to 25 µg/mL). No significant differences were presented applying NCs. The results obtained from this preliminary study pointed out the sensitivity of bacteria from blueberry microbiota to NBs and NCs containing curcumin, nevertheless further research should be carried out to evaluate the in vivo applicability of the nanotechnologies.