title: Kinetics of protein and textural changes in Atlantic salmon under frozen storage.
abstract: Fish proteins are highly susceptible to changes during frozen storage, leading to modifications in protein solubility, functionality, and structure, which affect the rheological properties, which, in turn, contribute to changes in techno-functional properties. Under frozen storage, these changes are the result of many physical and chemical modifications, especially structural and functional protein changes. The aim of this study was to evaluate and quantify protein and textural changes during frozen storage of Atlantic salmon (Salmo salar) fillets at four temperatures (268 K, 264 K, 260 K and 255 K). The Weibullian model was applied in order to understand the quality changes. Results for all frozen storage temperatures showed that total volatile basic nitrogen (TVB-N) did not reach the regulated limits (30-35 mg/100 g muscle), salt-soluble protein (SSP) decreased systematically and total nitrogen (TN) was constant. Hardness, adhesiveness, gumminess and chewiness levels decreased systematically at all temperatures, but cohesiveness and springiness values were relatively constant over time, at the same given temperature. A comparison between different temperatures showed an increase in the measurements observed. A kinetic analysis for TVBN, SSP, hardness, adhesiveness and chewiness, was performed. All quality indicators, except TVBN, showed reaction rates inversely proportional to the temperature, and fractional shape factors or orders of reaction. Using the Weibullian model, this study demonstrates that, in complex biological processes, quality indicators do not have an integer kinetic order and reaction rates are strongly temperature-dependent. Thus, this kind of model can be used to improve understanding, prediction, and control of the frozen storage process.
authors.affiliation: Aquaculture and Agrifood Resources Department, University of Los Lagos, Av. Fuchslocher 1305, Osorno, Chile. Electronic address: foodengfaab@gmail.com.
authors.forename: Fabián Alberto
authors.initials: FA
authors.lastname: Aguilera Barraza
authors.affiliation: Aquaculture and Agrifood Resources Department, University of Los Lagos, Av. Fuchslocher 1305, Osorno, Chile.
authors.forename: Roberto Agustín Quevedo
authors.initials: RA
authors.lastname: León
authors.affiliation: Aquaculture and Agrifood Resources Department, University of Los Lagos, Av. Fuchslocher 1305, Osorno, Chile.
authors.forename: Patricia Ximena López
authors.initials: PX
authors.lastname: Álvarez
mesh_terms: D000818:Animals; D029941:Fish Proteins / Q000276:immunology*; D061353:Food Storage; D005615:Freezing; D007700:Kinetics; D008962:Models, Theoretical; D020317:Salmo salar / Q000276:immunology*; D013696:Temperature
chemical_list: D029941:Fish Proteins
keywords: Ammonia (PubChem CID: 222); Boric acid (PubChem CID: 7628); Dimethylamine (PubChem CID: 674); Formaldehyde (PubChem CID: 712); Frozen storage; Hydrochloric acid (PubChem CID: 313); Kinetics; Mathematical modeling; Perchloric acid (PubChem CID: 24247); Potassium dihydrogen phosphate (PubChem CID: 516951); Protein and textural changes; Salmo salar; Trimethylamine oxide (PubChem CID: 1145); Weibull model