title: Effects of thermal processing and various chemical substances on formaldehyde and dimethylamine formation in squid Dosidicus gigas.
abstract: BACKGROUND
  Trimethylamine oxide (TMAO) in squid is demethylated to dimethylamine (DMA) and formaldehyde (FA) during storage and processing. This study examined the effects of thermal processing and various chemical substances on FA and DMA formation in squid.
  
  
  RESULTS
  The thermal conversion of TMAO was assessed by analysing four squid and four gadoid fish species, which revealed that FA, DMA and trimethylamine (TMA) were gradually produced in squid, whereas TMA increased and FA decreased in gadoid fish. A significant increase in both FA and DMA levels was observed in the supernatant of jumbo squid with increased heating temperature and extended heating time at pH 6-7. Ferrous chloride combined with cysteine and/or ascorbate had a significantly positive effect on FA formation in the heated supernatant of jumbo squid. No significant difference was observed in the levels of Cu and Fe in squid and gadoid fish. The capability of Fe(2+) to promote the formation of FA and DMA was not completely attributable to its reducing power in squid.
  
  
  CONCLUSIONS
  Non-enzymatic decomposition of TMAO was a key pathway during the thermal processing of jumbo squid, and Fe(2+) was a crucial activator in the formation of FA and DMA.
authors.affiliation: College of Food Science and Biotechnology, Zhejiang Gongshang University, Food Safety Key Lab of Zhejiang Province, Hangzhou 310035, China.
authors.forename: Junli
authors.initials: J
authors.lastname: Zhu
authors.forename: Jianrong
authors.initials: J
authors.lastname: Li
authors.forename: Jia
authors.initials: J
authors.lastname: Jia
mesh_terms: D000818:Animals; D001205:Ascorbic Acid; D003545:Cysteine; D049832:Decapodiformes; D004123:Dimethylamines / Q000378:metabolism*; D005296:Ferrous Compounds; D005399:Fishes; D005511:Food Handling / Q000379:methods*; D005557:Formaldehyde / Q000378:metabolism*; D006358:Hot Temperature; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007501:Iron; D008744:Methylamines / Q000378:metabolism; D017747:Seafood / Q000032:analysis*
chemical_list: D004123:Dimethylamines; D005296:Ferrous Compounds; D008744:Methylamines; D005557:Formaldehyde; C034516:dimethylamine; D007501:Iron; C005855:trimethyloxamine; D003545:Cysteine; D001205:Ascorbic Acid; C029451:ferrous chloride