title: Effect of sexual maturation on thermal stability, viscoelastic properties, and texture of female rainbow trout, Oncorhynchus mykiss, fillets.
abstract: The nutrient and energy demand of sexual maturation in many fish cultivars causes structural change to key contractile proteins and thereby, affects fillet firmness. Thermal denaturation and viscoelastic properties of white muscle from diploid (2N; fertile) and triploid (3N; sterile) female rainbow trout were investigated at 6 age endpoints from July 2008 through spawning in March 2009. Differential scanning calorimetry showed, in March, that the actin denaturation temperature (T(max,actin)) of 2N females was higher than that observed in 3N females (78.17 versus 77.27 °C). From 35 to 45 °C, viscoelastic measurement revealed that muscle from 2N females and younger fish (July, 16 mo) had greater elasticity (lower tan δ) than muscle from 3N females and older fish (November to March; 20 to 24 mo), respectively. The highest elastic response and the firmest fillets were observed in July. Raw fillets were softer (Allo-Kramer shear; P < 0.05) from September to January (288.77 g/g on average) than those collected in July (475.15 g/g) and March (366.79 g/g). Soft fillets became firmer after cooking except for January samples. Greater cook yield and softer fillets were observed in January compared to December. Lipid accumulation in 3N females may lubricate muscle fibers and protect them from losing functionality during the spawning season for animals on a high plane of nutrition.
  
  
  CONCLUSIONS
  The relationship between fish maturation, measured as egg development, and chemical characteristics of fillets from fertile and sterile fish was evaluated. Thermal denaturation and viscoelastic characterization revealed changes in stability and gelling properties of muscle proteins that were related to changes in fillet texture.
authors.affiliation: Division of Animal and Nutritional Sciences, West Virginia University, Morgantown, WV 26506-6108, USA.
authors.forename: Aunchalee
authors.initials: A
authors.lastname: Aussanasuwannakul
authors.forename: Greg M
authors.initials: GM
authors.lastname: Weber
authors.forename: Mohamed
authors.initials: M
authors.lastname: Salem
authors.forename: Jianbo
authors.initials: J
authors.lastname: Yao
authors.forename: Susan
authors.initials: S
authors.lastname: Slider
authors.forename: Meghan L
authors.initials: ML
authors.lastname: Manor
authors.forename: P Brett
authors.initials: PB
authors.lastname: Kenney
mesh_terms: D000199:Actins / Q000737:chemistry / Q000378:metabolism; D000818:Animals; D017756:Aquaculture; D055598:Chemical Phenomena; D004041:Dietary Fats / Q000032:analysis / Q000378:metabolism; D004548:Elasticity; D005260:Female; D029941:Fish Proteins / Q000737:chemistry / Q000378:metabolism; D005782:Gels; D006358:Hot Temperature; D055595:Mechanical Phenomena; D018656:Muscle Fibers, Fast-Twitch / Q000737:chemistry / Q000378:metabolism*; D017686:Oncorhynchus mykiss / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism*; D011003:Ploidies; D011489:Protein Denaturation; D017747:Seafood / Q000032:analysis*; D012621:Seasons; D012741:Sexual Maturation; D044366:Transition Temperature; D014783:Viscosity
chemical_list: D000199:Actins; D004041:Dietary Fats; D029941:Fish Proteins; D005782:Gels