Presence of 2-thiohydantoins in processed foods

Abstract

Isothiocyanates can react with amino acids to form 2-thiohydantoins. Among isothiocyanates, allyl isothiocyanate (AITC), the pungent component of wasabi and mustard, is often used as a wasabi-flavoring additive. In foods containing AITC (wasabi-fumi-pickles and wasabi-fuminoritsukudani), 3-allyl-2-thio-5- hydantoinpropionic acid (ATH-Glu), formed by reaction of AITC and glutamic acid, was identified using high-performance liquid chromatography/mass spectrometry (LC-MS). 3-Allyl-5-isobutyl-2-thiohydantoin (ATH-Leu), 3-allyl-5-benzyl-2- thiohydantoin (ATH-Phe), and 3-allyl-5-isopropyl-2-thiohydantoin (ATH-Val), the reaction products of AITC with leucine, phenylalanine, and valine, were also identified in wasabi-fumi-noritsukudani. This is the first report demonstrating the formation of 2-thiohydantoins in commercially processed foods.