The United Nations Food and Agriculture Organization has estimated that by 2025 global aquaculture will provide more than half of the world’s seafood supply. Now it is about 35 percent to 40 percent. With a growing industry comes growing waste. Louisiana seafood processors alone generate millions of pounds of aquatic-based food processing waste annually. Disposal of fisheries waste in Louisiana is a huge problem. Many processing facilities have a waste load of 1 million to 2 million pounds per year. Current disposal rates in the New Orleans area are $30 per ton, and a large plant may spend $2,000 to $3,000 per month in disposal fees. Several local landfills have already refused fisheries wastes because of the nitrogenous runoff that may be produced and the contamination of their truck weighing scales.
One traditional use of seafood waste has been low-value feeds and fertilizers. However, there is growing interest among seafood processors to obtain higher value from byproducts such as by recovering health-enhancing products. Fish byproducts include fish frames (bones), viscera, skin, roe, eyes, head and testes. Fishery waste is a mixture of many biologically active components that can be extracted to isolate different compounds. Functional foods, biochemicals and pharmaceuticals can be refined and used as anti-inflammatory agents, antimicrobials, antioxidants, enzymes, proteins, nucleic acids, calcium, oil, enzyme inhibitors, colors, pigments, dyes and caviar.
Researchers at the LSU AgCenter are developing commercially viable recovery methodologies for bioactive compounds such as protamine and collagen from Louisiana seafood waste products. The development of a biochemical industry that will help solve the waste disposal problem associated with fishery byproducts and generate more profit for seafood processors requires
a scientific information base.
Protamine and Collagen
One of the products that can be extracted from seafood waste is protamine, a small cationic peptide that shows potential as an antimicrobial agent. Its antimicrobial property, stemming from its ability to create cavities in microbial cell membranes, is similar to other cationic peptides such as defensins and nisin produced by organisms as a defense against microbial invasion.
Researchers at the LSU AgCenter are developing antimicrobial systems containing protamine for use in meat products and fresh produce. Initial studies have shown that protamine inhibited salmonella, E. coli and listeria in soy broth. In ground beef, protamine resulted in a reduction in salmonella, and reduction was observed for E. coli at refrigeration temperature.
Protamine also has applications in the control of fat intake and is a potential candidate for the control of food intake in diabetes.
Another product that can be extracted from seafood waste is collagen. This product is unique among body proteins because it contains hydroxyproline amino acids. It is the single most important protein of connective tissue and serves as the matrix on which bone is formed. It is found in the ligaments and tendons, forms scars to hold separated tissue faces together and is the strengthening glue between the cells of artery walls that enables them
to withstand the pressure of surging heartbeats. Successful medical and pharmaceutical applications of commercially available collagen include the treatment of hypertension, urinary incontinence and pain associated with osteoarthritis and inhibition of cancer spread in the body. The cosmetic industry uses collagen in personal care products. Food applications of collagen include clarification of alcoholic beverages and the preparation of gelatin. There is a large market for gelatin as an ingredient in food, pharmaceuticals, photographic
and personal care products.
The predominant source material for commercially available gelatin is animal tissue (skin, bone). Use of collagen and collagen-derived products from warm-blooded animal byproducts, however, has been called into question because of concern that bovine spongi-form encephalopathy (“mad cow” disease) may be transmitted to humans.
Marine Sources of Collagen
This concern is giving rise to new markets for marine sources of collagen. Marine collagen is considered a safer alternative to bovine or porcine skin materials. No evidence suggests that viral or sub-viral particles adapted to cold-blooded organisms can be transmitted to humans. Marine gelatin and collagen, especially those from some warm-water species, have physical and chemical properties similar to the gelatin and collagen from warm-blooded animals. This is not always true for gelatin from cold-water species.
Marine products can easily be certified as a Kosher quality product because there is no mixing of porcine and bovine tissues as occurs in red meat byproduct recovery. This designation is an important marketing element to many companies using gelatin or collagen as an ingredient. A marine collagen production facility would use only a limited number of species available from local processors in one given geographical area, so the sorting of species allowed as Kosher could be easily accommodated.
Scientists at the LSU AgCenter have received funding from the National Sea Grant to prepare collagen from Louisiana seafood processing waste for pharmaceutical and food applications. Collagen has been purified from finfish skins and scales. The collagen recovered was similar to bovine and porcine collagen in physicochemical properties (molecular size, viscosity, solubility and color). The molecular size of the collagen has been determined acceptable as a food ingredient.
Jack N. Losso, Assistant Professor; Masahiro Ogawa, Postdoctoral Researcher; Michael W. Moody, Professor and Head, Department of Food Science; Ralph J. Portier, Professor, Department of Environmental Studies; Kenneth W. McMillin, Professor, Department of Animal Science; Donal F. Day, Professor, Audubon Sugar Institute; Jon Bell, Assistant Professor, Department of Food Science; and Mark Schexnayder, Fisheries Agent, LSU AgCenter, Baton Rouge, La.
(This article was published in the fall 2002 issue of Louisiana Agriculture.)