36D-37

S. SATHIVEL, Fishery Industrial Technology Center, Univ. of Alaska, Fairbanks, School of Fisheries and Ocean Sciences, 118 Trident Way, Kodiak, AK 99615-7401

Pink salmon (Oncorhynchus gorbuscha) and red salmon (Oncorhynchus nerka) heads are good source of protein and oil. There is an opportunity to increase utilization of salmon heads to make food protein and oil ingredients and products. The objective was to isolate both soluble and insoluble protein fractions and oils from pink salmon (PO) and red salmon heads (RO) and evaluate rheological properties of emulsions made with salmon protein and oil and the unrefined salmon oils. Pink (P) or red salmon (R) heads were minced, and water added (water: mince=1:1, V/W). The mixture was heated at 85^o C for 45 minutes and the soluble protein (PS and RS), insoluble proteins (PIS and RIS), and fish oils (PO and RO) collected. Soluble and insoluble fractions were freeze-dried. Emulsions were prepared by adding water (36 g), salt (3 g) sugar (1.5 g), xanthan gum (0.5 g), salmon protein powder (5 g), vegetable oil (53 g), and lemon juice (1 g). Rheological properties of emulsions and fish oils were measured at using an AR 2000 Rheometer. The Arrhenius relationship was employed to calculate the average magnitudes of activation energy (Ea) for the oils. All emulsion samples were pseudoplastic fluids. The frequency sweep test showed that the PS and RS emulsions had higher viscoelastic characters than PIS and RIS emulsions. More than a 5 fold increase in the magnitude of the consistency index value was observed for both oils between 20^o C and –4^o C. RO had higher Ea (37 kJmol-1) values than PO (30 kJmol-1). The predicted viscosity obtained by the Arrhenius equation agreed with the experimental viscosity data. Soluble salmon head protein powders were better emulsifiers than the insoluble salmon head protein powders. The magnitude of the viscosity for salmon oils was greatly influenced at low temperatures.

Session 36D, Food Engineering: Rheology
8:30 AM - 12:00 PM, Monday AM Room Hall I-2

2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana