Chemical Characterization of Liver Lipid and Protein from Cold‐Water Fish Species

Abstract

The largest US harvests of marine fish for human consumption are from Alaska waters. Livers from these fish are combined with other fish offal and made into fish meal and oil or discarded. The purpose of this study was to characterize liver lipids and proteins from important commercial species including walleye pollock (WP), pink salmon (PS), Pacific halibut (PH), flat head sole (FS), and spiny head rock fish (RF), and underutilized species including arrow tooth flounder (AF) and big mouth sculpin (BS). Liver lipid content ranged from 50.3% in WP to 3.3% in PS. Protein content ranged from 7.7% in WP to 18.4% in BS. PS livers had the highest content of ω‐3 fatty acids at 336 mg/g of oil and AF had the lowest content at 110 mg/g of oil. There were significant differences in the content of 9 amino acids with methionine and lysine values ranging from 2.66% to 3.43% and 7.19% to 9.45% of the total amino acids, respectively. Protein from the cold water marine fish livers was of high quality and the oils contained substantial quantities of ω‐3 fatty acids. Fish livers had distinct chemical properties and can be used for the development of unique food ingredients.

By-products of farmed European sea bass (Dicentrarchus labrax L.) as a potential source of n-3 PUFA

“…Variable percentage of EPA and DHA were observed in fish oil obtained from commercial Alaskan fish by-products (Oliveira & Bechtel 2005;Bechtel & Oliveira 2006) and tuna by-products (Chantachum et al 2000;Selmi et al 2008).…”

“…These productions generate a significant percentage of by-products that need to be discarded in a controlled way, requiring a cost for both the producers and the environment. The alternative is to use it to extract bioactive compounds, such as peptides, oligosaccharides, fatty acids, enzymes, useful for biotechnological, pharmaceutical, nutraceutical applications and for fish oil, fishmeal, and fertilizer preparations (New & Wijkström 2002;Bechtel & Oliveira 2006;Kim & Mendis 2006). Among these bioactive compounds, n-3 PUFA can be particularly represented (Kim & Mendis 2006;Ferraro et al 2010) in relation to species-specific and eco-physiological factors (Ackman 1995;Sargent et al 2002).…”

Preliminary chemical and nutritional characterization of liver from longnose skates (Raja rhina)

“…There has been little systematic evaluation of elasmobranch liver proteins from a nutritional perspective; however, Bechtel and Oliveira (2006) have reported nutritional values of livers from 7 cold water marine fish species. Similar results were noted for the 3 abundant amino acids glutamic acid, aspartic acid and leucine.…”

“…Liver oil from commercial ray (Himantura bleekeri) represented 54% of the liver weight (w/w) (Né chet et al, 2007). The protein value of 10.9% in skate livers is about average compared to other cold water marine fish livers that ranged from 7.77% to 18.61% (Bechtel and Oliveira, 2006). Table 3 lists the amino acid composition of the livers as a percentage of total amino acid composition on a dry weight basis (%, w/w).…”

“…In Alaska most fish byproducts are discarded or made into meal and oil (Carpo and Bechtel, 2003); therefore, there is opportunity to enhance the utilization for skate byproducts. Currently, there is information on the livers of some commercial harvested marine fin fish (Bechtel and Oliveira, 2006), but little information on the nutritional and chemical properties of livers from cold water marine elasmobranchs (sharks, rays, skates, etc.) in general.…”