Quote from: noble ox on January 20, 2012, 07:22 PM
Anyone know how a flavour enhancer works 



? :
Yes, sort of... in the case of "meatiness" and monosodium L-glutamate (MSG) there is a synergistic relationship with inosene monophosphate (IMP) that results in an intensifying of meaty flavour perception, but the mechanisms behind this aren't too well understood (flavour science is quite a complicated area). MSG doesn't have much of a taste on it's own but when combined with IMP in equal mesaures it tastes about 20 times stronger.
In muscle tisssue, chemical energy is present as a molecule called adenosine triphosphate or ATP.
After death the ATP degrades by losing a phosphate molecule to become adenosine di-phosphate or ADP - this in turn loses another phosphate to become adenosine mono-phosphate or AMP.
The AMP molecule breaks down further by losing an H
2O and NH
3 resulting in the formation of the IMP molecule. Basically it is the interplay between the MSG/IMP that is responsible for promoting the perception of meatiness.
With me so far? Phew

In adddition, coooking meat also leads to the formation of compounds such as methyl furanolone as a product of heating IMP and other ribonucleotides and these also have a pronounced meaty odour and contribute to the sensation of meatiness.
Glutamate and IMP are present in lots of foods but some have more than others - for example parmesan can typically contain about 1200mg per 100g of MSG and tomato juice about 260mg per 100g - this is the basis for their use in bolognese type sauces. Typically beef and pork contain about the same levels of IMP but beef contains roughly twice the level of MSG.
Sorry it's a bit heavy going - but you did ask ;D