relative proportions depending on the nature
of the fat. Compounds from forage plants
contribute to the “cowy” flavor of beef.
Lambs and sheep store a number of unusual
molecules, including branched-chain fatty
acids that their livers produce from a
compound generated by the microbes in their
rumen, and thymol, the same molecule that
gives thyme its aroma. The “piggy” flavor of
pork and gamy flavor of duck are thought to
come from intestinal microbes and their fat-
soluble products of amino-acid metabolism,
while the “sweetness” in pork aroma comes
from a kind of molecule that also gives
coconut and peach their character (lactones).
Grass versus Grain In general, grass or forage
feeding results in stronger-tasting meat than
grain or concentrate feeding, thanks to the
plants’ high content of various odorous
substances, reactive polyunsaturated fatty
acids, and chlorophyll, which rumen microbes