[not_clear]

Interesting - the metafilter referenced elsewhere on the thread had a pointer to a paper about D-glutamate vs L-glutamate. Apparently, bacterial fermentation generates a fair amount of D-glutamate, but this is true of "naturally occurring" fermentation (such as in cheese) too.

The abstract claims foods to which MSG is added directly contained lower amounts of D-glutamate than foods where the MSG comes from fermented foods. I wonder why? Maybe due to better optimization / control for L-glutamate production in the bacteria?

http://onlinelibrary.wiley.com/doi/10.1002/chir.530060410/ab...