Most holograms are printed using a laser onto metal surfaces such as aluminum, but these
For food products, holograms can be made from nanoparticles that can generate active forms, but may be harmful to humans.
Another approach suggests creating edibleholograms on chocolate, but this process only works for certain types of confectionery, and each hologram design requires a new mold.
Bader Alqattan, Haider Butt and their colleagues wanted to find a safe, fast and universal way to apply edible holograms to various products.
To develop their method, researchersmade a solution of corn syrup, vanilla and water and dried it into a thin film. They coated the film with a thin layer of non-toxic black dye. Then used the method of direct laser interference pattern. After that, they got raised nanoscale lines that form a diffraction grating.
When light enters, the nanostructure diffractslight in a rainbow pattern of different colors that appear from different viewing angles. The team could change the intensity and range of colors at will.
However, before the edible holograms reachstore shelves, the researchers want to adapt this method to a food coloring that could replace the synthetic black dye that was used in the work.
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