Though definitions of what is—and is not—“nano” vary, the US Food and Drug Administration (US FDA) uses three criteria:
- “Research and technology development at the atomic, molecular or macromolecular levels, in the length scale of approximately 1–100 nanometer range.” (Just a fraction of the width of a human hair.)
- “Creating and using structures, devices and systems that have novel properties and functions because of their small and/or intermediate size.”
- “Ability to control or manipulate on the atomic scale.”
Key nanomaterials include fullerenes, which are typically spherical, closed and hollow aromatic carbon compounds composed of 12 pentagonal and varying numbers of hexagonal faces, and nanotubes, which are typically carbon microscopic tubes measured in nanometers. These materials can be used for an almost endless array of effects, including controlled release of flavors and fragrances, masking of off-flavors, and protection of volatile flavor compounds in the service of enhanced shelf-life. But health worries abound.