17G-10 |
|
S. SATHIVEL, Fishery Industrial Technology Center, Univ. of Alaska, Fairbanks, School of Fisheries & Ocean Sciences, 118 Trident Way, Kodiak, AK 99615-7401 In Alaska over one million metric tons of Walleye Pollock (Theragra chalcogramma) is harvested annually. Pollock byproducts including liver and other viscera components are often made into fish meal and fish oil. Much of the oil in Pollock is found in the liver and viscera. There is little information available on rheology properties, melting point, specific heat capacity, enthalpy, and color of oils from Pollock. The objective of this study was to evaluate rheological properties, melting point, specific heat capacity (Cp), and enthalpy color of oil Pollock. Pollock oil was collected from a large fish meal producer in Alaska during the Pollock season between late March to early April (LO). Pollock oils were also made in the University of Alaska pilot plant from Pollock viscera (VO). The oil samples were tested for rheological properties using a rheometer at –4, 0, and 25 C. Differential Scanning Calorimetry (TA instruments) was used to determine melting point, Cp, and enthalpy of the oils. Oil melting points ranged from –32.9 to 6.2 and –34.4 to 14.48 C for VO and LO, respectively. Two very notable melting points were observed at –13.5 C and –1.4 C for VO. LO had only one notable melting point at –12.1 C. The enthalpy was 34.8 j/g for VO and 31.6 j/g for LO. A Cp (j/g °C) range of 0.6 to 3.5 was found for LO and 1.4 to 4.6 for VO. The oils exhibited Newtonian flow behavior. At –4 C Pollock oil from the LO generated higher apparent viscosity than VO oil samples. The color of LO was more yellowish than VO. Knowledge of physical properties of the Pollock oils is essential for the design of proper unit operations, quality evaluation, and production cost analysis.
Session 17G, Food Engineering: Physical, chemical and electrical properties
|