title: Chemical compositions and muddy flavour/odour of protein hydrolysate from Nile tilapia and broadhead catfish mince and protein isolate.
abstract: Chemical compositions and muddy compounds in dorsal and ventral muscles of Nile tilapia and broadhead catfish were comparatively studied. On a dry weight basis, Nile tilapia was rich in protein (93.1-93.8%), whilst broadhead catfish contained protein (55.2-59.5%) and lipid (36.6-42.4%) as the major constituents. Ventral portion had higher lipid or phospholipid contents with coincidentally higher geosmin and/or 2-methylisoborneol (2-MIB) contents. Geosmin was found in mince of Nile tilapia and broadhead catfish at levels of 1.5 and 3.2μg/kg, respectively. Broadhead catfish mince had 2-MIB at level of 0.8μg/kg, but no 2-MIB was detected in Nile tilapia counterpart. When pre-washing and alkaline solubilisation were applied for preparing protein isolate (PI), lipid and phospholipid contents were lowered with concomitant decrease in geosmin and 2-MIB contents. Protein hydrolysate produced from PI had a lighter colour and a lower amount of muddy compounds, compared with that prepared from mince. Therefore, PI from both Nile tilapia and broadhead catfish could serve as the promising proteinaceous material, yielding protein hydrolysate with the negligible muddy odour and flavour.
authors.affiliation: Department of Food Technology, Faculty of Agro-Industry, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand.
authors.forename: Suthasinee
authors.initials: S
authors.lastname: Yarnpakdee
authors.forename: Soottawat
authors.initials: S
authors.lastname: Benjakul
authors.forename: Pimpimol
authors.initials: P
authors.lastname: Penjamras
authors.forename: Hordur G
authors.initials: HG
authors.lastname: Kristinsson
mesh_terms: D000818:Animals; D001892:Camphanes / Q000032:analysis; D002397:Catfishes; D023681:Cichlids; D005396:Fish Products / Q000032:analysis*; D029941:Fish Proteins / Q000737:chemistry; D005511:Food Handling; D006801:Humans; D009284:Naphthols / Q000032:analysis; D009812:Odorants / Q000032:analysis*; D011492:Protein Hydrolysates / Q000737:chemistry*; D013649:Taste
chemical_list: D001892:Camphanes; D029941:Fish Proteins; D009284:Naphthols; D011492:Protein Hydrolysates; C005536:2-methylisoborneol; C001278:geosmin
keywords: Broadhead catfish; Lipid; Muddy compounds; Nile tilapia; Protein hydrolysate