On Food and Cooking

concentrated natural source of monosodium
glutamate. Another taste enhancer that’s
synergistic with glutamate, GMP (guanosine
monophosphate), was first discovered in
shiitake mushrooms, and contributes to the
rich taste.
The characteristic aroma of fresh common
mushrooms is mainly due to octenol (an 8-
carbon alcohol), which is produced by
enzymes from polyunsaturated fats when the
tissue is damaged, and which helps deter
attack by some snails and insects. More
octenol is generated from the gill tissues than
from other parts, and this is one reason that
common mushrooms with immature,
unopened caps are less flavorful than the
mature version with prominent gills. Brown
and field mushrooms have more flavor than
the white mushroom, and the “portobello,” a
brown mushroom allowed to mature for an
additional five or six days until it’s about 6
in/15 cm across, is especially intense.