Holograms have been used for various applications - passports and licenses, credit cards, product packaging. Now, edible holograms could soon be used to decorate food items.
Researchers have found a new laser-based printing method that could apply nanostructured holograms on food, particularly dried corn syrup film. Besides aesthetic purposes, edible holograms could indicate food safety, a new method for product labeling, or even note sugar content.
Printing Holograms on Foods
Holograms are generally laser printed on metal surfaces, such as aluminum, which is unfortunately inedible. While nanostructured holograms have been previously proposed for foods, tiny particles in the hologram can lead to reactive oxygen compounds, making them harmful in the event of human consumption. A news release from the American Chemical Society (ACS) reports that a particular approach attempted to integrate molded edible holograms on chocolate to find that it only works on certain kinds of chocolate. Additionally, a particular design will require a different mold.
A new study, led by Bader AlQattan and Haider Butt, focused on finding a safe and feasible way of including edible holograms on food.
First, they created a solution made from corn syrup, vanilla, and water. The mixture was then dried out to create thin films, which were later coated with a layer of non-toxic black dye. Researchers etched off the unnecessary parts of the black dye using a technique called direct laser interference patterning. What was left on the film are raised, nanoscale patterns that created a diffraction grating - an optical component that diffracts light, creating visual patterns necessary in creating holograms.
When light hits the film, the nanostructured patterns diffract the light into a rainbow-colored pattern, with the resulting colors dependent on the angle of viewing. Furthermore, researchers report that the intensity and colors appearing on the film could be controlled simply by altering the spaces between the grating lines or altering the corn syrup mixture's sugar content.
However, before edible holograms become commercially available, researchers suggest adapting their new technology first to food-grade dyes, replacing the synthetic, non-toxic black dye used in the first phase of their experiments.
How Holograms Work
Holograms, from the Greek for "whole picture," refer to real-world recordings of a pattern. Using light diffraction to reproduce another 3D light field - an image that retains the original image's depth. Hungarian-British physicist and engineer Dennis Gabor invented holography in 1947, receiving the 1971 Nobel Prize in Physics for his accomplishment.
Basically, holography allows the recording of a light field, later reconstructing it even when the original light field and objects are present. It has been compared to recording sounds, but this time with light imprints.
Compared to photography, holography allows for viewing multiple angles with the depth and parallax of the original scene. In contrast, while photography is possible with normal light sources such as electric or natural lighting, holograms could only be recorded using special lights, like lasers.
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