Why does vanillin sugar turn pink to brownish red after a year?

Hello, I make vanillin sugar (sugar, aromas - vanillin, ethyl vanillin)  - why does it turn pink to brownish red after a year? Br, Solvita.

Sounds likely to be Maillard reaction causing discolouration of the vanillin - have a read of e.g. https://www.research...try_of_vanillin

How are you storing it?

Heat and light are the enemies of flavors; the discoloration could be due to oxidation.  I've seen orange extract change colors from orange, to yellow, to clear over the period of just a few months of ambient storage in a clear container.  With this color change also comes a change in flavor.  Try storing your vanilla sugar in a cool, dark place.  This doesn't have to mean refrigeration either, it could be storage in amber glass away from sunlight and heat.

Hi,

Storage conditions: Stable temperature (23 degrees C), Relative humidity < 75 %.

Hi,

Storage conditions: Stable temperature (23 degrees C), Relative humidity < 75 %.

What about the storage container?  Is it clear or opaque?

Hi,

Storage - cardboard box.

If cardboard is the primary packaging, then there is no protection from oxidation.  It needs to be in some form of sealed container made of LDPE, HDPE, or glass that does not allow air permeability.