4-Hexylresorcinol

4-Hexylresorcinol is a phenolic compound used as a colour stabiliser in crustacean processing. Its specific food application is the prevention of enzymatic melanosis — commonly called "black spot" — in shrimp, prawns, lobster, and other crustaceans. Melanosis occurs rapidly after harvest when the enzyme polyphenol oxidase reacts with phenolic substrates in crustacean tissue, producing black pigmentation that is unappealing to consumers but does not indicate spoilage or safety concerns. 4-Hexylresorcinol inhibits polyphenol oxidase efficiently at low concentrations, maintaining the natural appearance of crustaceans during distribution and retail display.

JECFA evaluated 4-hexylresorcinol in 1996 and established an ADI of 0.6 mg/kg body weight per day, based on animal safety studies. It is applied only to the external surface of crustaceans and is not permitted for use in other food categories. The amount present on crustacean flesh after processing and cooking is regulated by maximum residue limits. 4-Hexylresorcinol is absorbed from the gastrointestinal tract and metabolised via glucuronide and sulphate conjugation, followed by urinary excretion.

4-Hexylresorcinol is approved in the EU as E586 exclusively for surface treatment of fresh and frozen crustaceans. It has also found pharmaceutical applications, including as the active ingredient in some antiseptic throat lozenges, reflecting its antimicrobial properties. In food, it may be encountered in pre-packaged shrimp, prawns, and similar crustacean products. Consumers with shellfish allergies are already advised to avoid these products; for those without shellfish allergy, E586 at permitted residue levels presents no identified consumer health risk. Organic or untreated crustaceans may develop melanosis more rapidly than treated products but remain safe to eat.