1. You need really good surface contact to get the diffraction on, so you can only really apply it to flat, uncurved surfaces
2. You need to apply it while the chocolate is hardening. If you're using a mold, you cast the chocolate upside-down so only the base is exposed during setting. You can't diffract the part people will actually see.
3. The effect is really fragile. Chocolate melts at around body temperature, so if you hold the piece for too long, the diffraction disappears. I've been able to transport diffractive chocolate in a padded box but don't think I could wrap the chocolate directly.
I assume the transportation is the real problem. Even taking this sort of thing home from a store might lose the effect.
I can get a pretty decent temper on chocolate and I make bonbons once in a while, but I have still found that you can lose fine surface details with a temperature that is a comfortable "room temp" for humans.
It's something that would need to be created in a retail confectionary for immediate consumption. And, people might demand refunds when the slightest heat ruins it should they attempt to transport them without a cold chain.
1. You need really good surface contact to get the diffraction on, so you can only really apply it to flat, uncurved surfaces
2. You need to apply it while the chocolate is hardening. If you're using a mold, you cast the chocolate upside-down so only the base is exposed during setting. You can't diffract the part people will actually see.
3. The effect is really fragile. Chocolate melts at around body temperature, so if you hold the piece for too long, the diffraction disappears. I've been able to transport diffractive chocolate in a padded box but don't think I could wrap the chocolate directly.