POST-HARVEST
Bromophenols and Their Contribution to Seafood Flavor: From Ocean-Like to Iodine By George Baker
Bromophenols are compounds found in low concentrations in wild
seafood that contribute to key seafood flavors and are sometimes added to aquaculture feed, either directly or indirectly.
B
romophenol compounds in aquaculture feed are either added directly from manufactured chemical sources or indirectly by using 10% or more shrimp head meal or other crustacean by-product meals (Whitfield 2002). It is postulated that depending on the type and concentration of bromophenol compound mixtures and the component tissues in seafood that bromophenols are found (i.e. fatty tissues or moisture) they have either pleasant “ocean-like” flavors or “iodine-/ phenolic-like” off-odors. For example, shrimp containing no to very low concentrations of total bromophenols are said to have a “bland” sensory profile. Low concentrations of bromophenols in shrimp provide “ocean-like” aroma and taste in cooked shrimp. However, at total bromophenol concentrations (TBC) above 23 µg/kg, the sensory perception of “iodine-like” flavor in shrimp is apparent (Savoie 2008). Whole wild shrimp reportedly have a TBC that ranges from 9.5 µg/kg to 1114 µg/kg dependent on species, 58 »
location, and what time of year they are harvested (Whitfield 2002). Seawater itself has an average bromine concentration of 65 µg/kg (Savoie 2008). Wild sources of bromophenols are found in the diet of shrimp by way of their consumption of polychaetes, different types of algae, sponges, and worms of the Annelida phylum. Moreover, Whitfield (2002) found that 2,6-dibromophenol and 2,4,6tribromophenol added to shrimp aquaculture feed individually did not have that much impact on producing “ocean-like” or “crab-like” flavor, but when added together contributed to “briny” and “iodine-like” off-flavors.
Figure 1. Chemical Structure of 2-bromophenol. Source: By Yikrazuul - https://commons.wikimedia.org/w/ index.php?curid=6899888
Other investigators noticed dramatic increases in the sensory detection threshold of individual bromophenol compounds when prepared in an oil versus aqueous matrix.
What Are Bromophenols? Bromophenols are brominated phenolic compounds found in certain types of marine algae, marine worms, sponges, bryozoans, food ingredients, agricultural chemicals, and even plastics. Reported bromophenol classes in seafood include mono-, di-, and tribromophenols and their isomers. Bromophenols have been reported to have natural nutraceutical properties that prevent diabetes mellitus in humans because of their high alpha-glucosidase inhibitory activity (Kim 2008 – Phytochemistry). Certain bromophenols have been shown to possess antioxidant, antimicrobial, anti-cancer, anti-inflammatory, and anti-thrombotic effects in humans (Liu 2011). Alternatively, not all bromophenols show beneficial health effects. Some bromophenols such as