Effect of sexual maturation on thermal stability, viscoelastic properties, and texture of rainbow trout, Oncorhynchus mykiss, fillets

Authors: AUSSANASUWANNAKUL, AUNCHALEE - West Virginia University; Weber, Gregory - Greg; SALEM, MOHAMED - West Virginia University; YAO, JAINBO - West Virginia University; SLIDER, SUSAN - West Virginia University; MANOR, MEGHAN - West Virginia University; KENNEY, P. BRETT - West Virginia University

Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/17/2011
Publication Date: 1/19/2012
Citation: Aussanasuwannakul, A., Weber, G.M., Salem, M., Yao, J., Slider, S.D., Manor, M.L., Kenney, P. 2012. Effect of sexual maturation on thermal stability, viscoelastic properties, and texture of rainbow trout, Oncorhynchus mykiss, fillets. Journal of Food Science. 77(1):S77-S83.

Interpretive Summary: The nutrient and energy demand of sexual maturation in many fish cultivars causes structural change to key contractile proteins of muscle and thereby affects fillet firmness. Thermal denaturation and viscoelastic properties of white muscle from diploid female rainbow trout that have the normal two sets of chromosomes and triploid female rainbow trout that have three sets of chromosomes and are therefore infertile and do not grow ovaries, were investigated during sexual maturation from July through spawning in March. The females were maintained on a high nutritional plane. Actin is a primary structural protein in muscle. Differential scanning calorimetry showed, in March, that higher temperatures were required to denature actin of diploid females than triploid females. Viscoelastic measurement revealed that muscle from diploid females and younger fish (July, 16 mo) had greater elasticity than muscle from triploid females and older fish (November-March; 20 -24 mo), respectively. The highest elastic response and the firmest fillets were observed in July. Raw fillets were softer from September to January than those collected in July and March. 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 triploid females may lubricate muscle fibers and protect them from losing functionality during the spawning season for animals on a high plane of nutrition. In all, sexual maturation brings about many changes in fillet texture, nutrient composition, and cook yield, even while on a high nutritional plane.

Technical 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 v. 77.27 degrees C). From 35 to 45 deg C, viscoelastic measurement revealed that muscle from 2N females and younger fish (July, 16 mo) had greater elasticity (lower tan ) than muscle from 3N females and older fish (November-March; 20 -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.