Submitted to: Journal of Food Science and Technology
Publication Type: Abstract Only
Publication Acceptance Date: March 15, 2005
Publication Date: July 18, 2005
Citation: Bechtel, P.J. 2005. Chemical and nutritional properties of pollock viscera and liver meal. Journal of Food Science and Technology.
The harvest of Alaska pollock (Theragra chalcogramma) was over one million metric tons in 2000 and it has been estimated that viscera constitutes approximately 21% of the fish weight. Our previous studies have characterized pollock viscera and there is the potential to make novel protein ingredients from both pollock liver and pollock viscera with the liver removed. The objective of this study was to chemically and nutritionally characterize pollock liver and viscera with the liver removed. Fresh pollock viscera with the roe remove was collected from a commercial processing plant and used to make three samples, which were viscera with liver removed (V-L), liver (L), and the viscera with liver left in the sample (V+L). All samples were analyzed for proximate composition and freeze dried L and V-L samples were analyzed for amino acid content, elemental analysis, protein solubility, pepsin digestibility, and color. Proximate compositions of the samples were different (p>0.05) for moisture contents (L=43.3%, V+L=66.6%, V-L=81.7%), fat contents (L=44.4%, V+L=19.3%, V-L=1.9%), and protein contents (L=10.9%, V+L=12.9%, V-L=14.7%), but had similar ash contents (L=1.1%, V+L=1.3%, V-L=1.7%). Freeze dried L was darker in color than freeze dried V-L. There were significant differences in the amino acid composition with V-L having higher percents of ALA, ARG, LYS and PRO and L having higher percentages of ILE, LEU, MET, PHE, TYR, and VAL. L and V-L had high percent pepsin digestible values. V-L had a greater percent P and Ca and L had higher contents of Cu, Zn, and Fe. Both pollock liver and viscera minus liver have very different proximate compositions and other properties; however, both of the potential ingredients have high quality protein quality and elemental compositions.