Chemistry of Off-Flavours in Marine Organisms

Abstract

Edible marine and fresh-water organisms are occasionally affected by off-flavours and taints. In coastal and estuarine areas near industrial sites the contamination is usually by compounds of industrial origin. However, unpolluted environments can also be a source of off-flavour compounds. For example, earthy/muddy off-flavours are caused by bioaccumulation of metabolites produced during algal blooms. Recent studies have also shown that garlic and iodoform-1ike off-flavours in marine crustacea are caused by compounds which can occur naturally in algae, bryozoa and debris. Compounds derived from these sources include the extremely potent trimethylarsine, 2-bromophenol and 2,6-dibromophenol. This paper examines the biological origins of such compounds, including their possible production from non-odorous precursors, and discusses their chemistry with special reference to their identification, quantitative analysis and sensory properties.