@Chris, you might be able to answer this, I have heard Heston say that Star Anise can boost umami flavors when paired with Caramelized Onions.
http://www.guardian.co.uk/lifeandstyle/2005/jun/11/foodanddrink.shopping4 .
Does anyone have any idea in the chemistry behind this, I find it very interesting and would love to know more. I know
@michael_natkin writes about the technique on Herbivoracious. I would assume that phenols are involved, but that is just a guess because they seem to be volatile and like to reaction with things...
Needless to say I have tried the technique and it does work well and regardless of whether there is an answer in the literature I ail continue to use it