title: Development of a new method for determination of total haem protein in fish muscle.
abstract: Using classic haem protein quantification methods, the extraction step in buffer or acid acetone often becomes limiting if muscle is oxidised and/or stored; haem-proteins then tend to bind to muscle components like myofibrils and/or biomembranes. The objective of this study was to develop a new haem protein determination method for fish muscle overcoming such extractability problems. The principle was to homogenise and heat samples in an SDS-containing phosphate buffer to dissolve major muscle components and convert ferrous/ferric haem proteins to hemichromes with a unique absorption peak at 535 nm. Hb-recovery tests with the new and classic methods showed that the new method and Hornsey's method performed significantly better on fresh Hb-enriched cod mince than Brown's and Drabkin's methods; recovery was ⩾98%. However, in highly oxidised samples and in cod protein isolates made with acid pH-shift processing, the new method performed better than Hornsey's method (63% and 87% vs. 50% and 68% recovery). Further, the new method performed well in fish muscle with ⩽30% lipid, <5% NaCl and pH 5.5-7.0; it was also unaffected by freezing/frozen storage.
authors.affiliation: Department of Chemical and Biological Engineering-Food Science, Chalmers University of Technology, SE 412 96 Gothenburg, Sweden; Department of Agro-Industry, School of Agricultural Technology, Walailak University, Thasala, Nakhon Si Thammarat 80161, Thailand. Electronic address: cmanat@wu.ac.th.
authors.forename: Manat
authors.initials: M
authors.lastname: Chaijan
authors.affiliation: Department of Chemical and Biological Engineering-Food Science, Chalmers University of Technology, SE 412 96 Gothenburg, Sweden. Electronic address: undeland@chalmers.se.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Undeland
mesh_terms: D000818:Animals; D055598:Chemical Phenomena; D005399:Fishes; D005504:Food Analysis; D061353:Food Storage; D005615:Freezing; D006420:Hemeproteins / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D018482:Muscle, Skeletal / Q000737:chemistry*; D017747:Seafood / Q000032:analysis; D012965:Sodium Chloride / Q000032:analysis
chemical_list: D006420:Hemeproteins; C001332:hemichrome; D012965:Sodium Chloride
keywords: Fish muscle; Haem proteins; Haemoglobin; Hemichrome; Method; Myoglobin; Oxidation; Quantification; Sodium dodecyl sulphate