| Approximately
90 percent of all shrimp consumed in the United States are
imported, the majority which are farm raised. Many U.S.
consumers are oblivious to the differences in shrimp flavors.
However, for true shrimp connoisseurs there are distinct
taste differences. What causes these taste differences was
the focus of a research paper by members of the Texas Sea
Grant Extension Program.
Flavor
is a combination of taste, smell and texture. Taste is normally
classified as sweet, sour, salty, bitter, etc. The senses
of taste and smell can be quite keen and has led to the
investigation of what tastes are preferred by consumers.
In shrimp, flavors have been described as “shrimp
like”, “ocean like”, “crab like”
or “slightly iodine.” It is incorrectly assumed
by many consumers that seafood products are high in salt.
In fact, fish and shellfish harvested from ocean waters
are actually low sodium foods. For example, a 3.5 oz serving
of shrimp contains approximately 148 mg sodium, while two
frankfurters contain 980 mg sodium.
So,
what gives wild shrimp its distinct flavors? The answer
is a group of chemical compounds known as bromophenols which
occur in small amounts in the muscle tissue of wild sea
foods. The absence of bromophenols in aquaculture produced
and freshwater fish and shell fish is described as mild-flavored,
bland and even earthy. An attempt by shrimp aquaculture
operations to mimic the unique flavors of wild shrimp led
to the addition of bromophenol compounds to the diet of
farm raised shrimp. However, repeated trials have not been
able to replicate the flavors of wild shrimp.
Freshwater
simply does not have phenols or bromine to impart into the
flesh of its inhabitants, while seawater has an average
concentration of 65 parts per billion (ppb) bromine. The
source of bromophenols in wild caught shrimp is derived
through their natural diet. The benthic (or bottom dwelling)
organisms which are fed on by shrimp are high in bromophenol
concentrations. The highest concentrations have been found
in polycheate worms. Polycheates from muddy sea bottoms
have the highest concentrations of bromophenols, while those
from sandy or shell bottom areas had significantly less.
Research
has found that the average concentration in seafood is about
3 ppb and that bromophenol does not accumulate in muscle
tissue, but leaches out over time causing varying degrees
of the flavor depending on the organism’s recent feeding
habits. At around 23 ppb or greater bromophenol, shrimp
are described as having a strong iodine flavor and are considered
by some as tainted flavor. Remember, our sense of taste
is quite sensitive, and the difference in optimum and tainted
flavor (20ppb) is miniscule.
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