Submitted to: International Journal of Food Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/15/2005
Publication Date: 5/20/2006
Citation: Sathivel, S., Bechtel, P.J. 2006. Properties of soluble protein powders from Alaska pollock (Theragra chalcogramma). International Journal of Food Science and Technology 41:520-529. Interpretive Summary: The pollock harvest in Alaska was 1.4 million metric tons in 2003, and it has been estimated that the yield of by-products from processing is approximately 66%. The objective of this study was to characterize soluble freeze-dried fish protein powders made from pollock by-products including trimmings (PTSP), frame (PFSP), head (PHSP), liver (PLSP), whole viscera (PVSP), and viscera without liver (PVWLSP) for potentially uses as protein ingredients. Highly soluble protein powders were made from each of the pollock by-products and there were differences in the properties of the protein powders. PVSP and PLSP had the highest percent fat. The soluble protein powders from pollock by-products exhibited many desirable functional properties. PLSP had the highest emulsifying capacity and all powders had similar emulsifying stability value. PFSP had the highest and PVSP the lowest fat adsorption values. The essential amino acid content of all the pollock soluble protein powders exceeded adult human requirement. Rheology studies showed that emulsions made from the pollock soluble protein powders had viscoelasticity properties. The protein powders from pollock by-products have the potential to be used in the food and feed industries due to their desirable functional and nutritional properties.
Technical Abstract: Soluble protein powders were produced from pollock by-products and evaluated for their functional, nutritional and rheological properties. Soluble protein powders were made from pollock viscera (PVSP), viscera without liver (PVWLSP), heads (PHSP), frames (PFSP), trimmings (PTSP), and liver (PLSP) and had protein contents ranging from 65.0 to 78.9%. Yield of PVWLSP was higher than that of other pollock proteins powder and PTSP had the highest nitrogen solubility value (85.7%). Emulsion capacity and emulsion stability of the pollock protein powders ranged from 29 to 34.5 (mL of oil/200 mg of protein) or 65.3 to 77.6%. Highest and lowest fat adsorption values were observed for PFSP (10.6 mL of oil/g protein) and PVSP (4.1 mL of oil/g protein), respectively. Pollock protein powder samples were good sources in K, P, and Mg and essential amino acids. Emulsions made with the pollock soluble protein powders exhibited viscoelastic characteristics. Soluble protein powders made from pollock by-products have the potential to be useful protein ingredients.