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United States Department of Agriculture

Agricultural Research Service

2009 Annual Report

1a.Objectives (from AD-416)
The over-arching goal of this project is to develop new knowledge to increase the value of underutilized seafood processing by-products for aquaculture and agriculture in a sustainable manner. This will be achieved by accomplishing the three objectives listed below. 1. Elucidate the chemical, biological, and physical properties of underutilized Alaska fish by-products and their biochemical constituents to identify properties/compounds that can be used to make new and improved aquaculture and agriculture feed ingredients, and other high value products. 2. Improve processes and methods for analysis, collection, and storage of raw materials, to retain the chemical, biological, and physical qualities of Alaska fish processing raw materials for developing new and improved ingredients/biochemicals. 3. Make and evaluate the value of new and improved aquaculture and agriculture ingredients and feeds from underutilized Alaska seafood by-products and their constituents. Implementation memo (revised) 130 will assist in evaluating the technical and economic feasibility of developing sources of nutrients (protein and oils) from on-shore and off-shore fish processing by-products for the emerging organic aquaculture industry. The research on the objectives identified in the implementation memo will be conducted under existing Objective 2, subobjective 2.3.

1b.Approach (from AD-416)
The overall goal of this research project is to develop new knowledge to increase the value of seafood processing by-products for aquaculture, agriculture and other high value uses in a sustainable manner. Implementation memo (revised) 130 will allow the technical feasibility to be evaluated by first examining the definition of a sustainable by-product source and the standards for organic aquaculture ingredients. In light of the definitions and standard, by-products currently produced by fish oil and meal plants in Alaska will be evaluated. Initial effort would focus on utilization of by-products from the only two sustainable fisheries in the United States, which are the Alaska pollock and salmon fisheries. Altering existing processing methods or incorporating new methods to meet the organic standards will be explored. Organic products will be produced and chemical and nutritional properties characterized. In addition, properties such as lipid oxidation will be evaluated during storage and distribution. Additional studies will evaluate the feasibility to produce unique products such as palatability enhancers and feed attractants for organic aquaculture.

3.Progress Report
FISH OILS 1. Neutralization and adsorption processes were evaluated for purification of unrefined salmon oils. 2. The effects of temperature on the viscosity and oxidation rates of crude salmon oil was studied. 3. Smoking was evaluated as a method for stabilizing PUFA-rich oils from salmon byproducts against oxidation.

STABILIZING BYPRODUCTS AND EVALUATING QUALITY DURING STORAGE 1. The effects of storage time and temperature on the quality of separate salmon byproducts was completed. 2. A one year storage study at two temperatures for salmon and pollock byproduct meals and oils was completed. 3. A new analytical method was developed for determination of biogenic amines and vitamin concentrations in fishery products.

FISH GELATINS 1. A study was completed on modifying fish gelatin film properties by varying drying conditions. 2. A study was completed in which electrospun fibers of poly(vinyl alcohol) and poly(lactic acid) were blended with pollock gelatin and then evaluated for biomedical applications. 3. A study is in progress characterizing the properties of nano-emulsions made with fish gelatins for use in edible films and coatings.

BYPRODUCT CHARACTERIZATIONS AND PROCESSES 1. Byproducts from skates and black rockfish were characterized for their use in food and feed ingredients. 2. The chemical characterization of byproducts from both fall and spring harvested pollock was completed and is being analyzed. 3. A study is in progress to determine optimal methods of drying fish heads. 4. The chemical characterization of byproducts from watermarked pink and chum salmon harvested late for their roe was completed. 5. Stickwater protein, concentrated by membrane fractionation, is being chemically and physically characterized. 6. Use of innovative membrane technologies to separate residual oils from stickwater is being studied. 7. Byproduct hydrolysates with different size peptides have been made and are being characterized for later testing in animal models.

AQUACULTURE AND ANIMAL TRIALS 1. A study on the nutritional quality of pollock liver and testes meals in the diets of Pacific threadfin was completed. 2. A study on the effects of salmon hydrolysates on cholesterol metabolism in hamsters was completed. 3. A trial using Alaskan fish testes meal supplementation to an all-plant diet for trout was completed 4. A study using fish bone meals as mineral supplement in an all-plant diet for trout was completed. 5. An investigation into the utility of employing Alaskan pollock oil to increase sow litter size is in progress. 6. A study on the nutritional quality of pollock viscera meal in the diets of hybrid striped bass is ongoing.

1. EFFECTS OF STORAGE TIME AND TEMPERATURE ON THE QUALITY OF SEPARATED BYPRODUCTS There is need for information on how storage time and temperature affect individual byproducts such as heads, viscera and frames. ARS scientists at Fairbanks, AK studied pink salmon and pollock byproduct parts, stored at two temperatures. Rates of change for oxidation, spoilage and the formation of biogenic amines were different for each species’ heads and viscera. The results suggested that if byproduct parts are to be separated, inhibition of microbial growth in viscera and protection against oxidation in heads should be considered during storage of pink salmon. This research provides guidance on storage time and temperature of separated raw byproducts.

2. CHEMICAL CHARACTERIZATION OF WATERMARKED CHUM AND PINK SALMON BYPRODUCTS When pink and chum salmon are harvested for high quality roe, the remaining carcass has less value. This study by ARS scientists at Fairbank, AK in cooperation with the university of Alaska scientists was designed to characterize late-run chum and pink salmon byproducts derived from fish that showed advanced stages of skin watermarking. Samples were obtained from commercial processors. Analyses included the proximate, fatty acid, amino acid, mineral, vitamins and biogenic amines concentrations. The nutritional quality of the flesh was good but there were chemical differences. These results will be used by the processing industry to increase the utilization of late pink and chum salmon.

3. ELECTROSPUN FIBERS CONTAINING FISH GELATINS Gelatin incorporated into electrospun fibers can improve cell growth in tissue engineering applications. However, no one has evaluated using low melting point gelatins isolated from cold water fish skin. Gelatin from Alaskan pollock was incorporated into electrospun fibers by ARS scientists in Fairbanks, AK. The pollock gelatin was blended with the biodegradable polymers polylactic acid and polyvinyl alcohol. This is the first time a gelatin sample was electrospun directly from water at room temperature. The fibers had diameters of several hundred nanometers, providing high surface areas and may have biomedical applications such as wound dressing.

4. STABILIZING PUFA-RICH OILS FROM SALMON BYPRODUCTS Valuable salmon oils can be extracted from fish processing wastes, but they must be stabilized immediately to prevent damage to long-chain polyunsaturated fatty acids. Smoke-processing was evaluated by ARS scientists at Fairbanks, AK in cooperation with the University of Alaska scientists as a technology to reduce oxidation of salmon oil. Salmon heads exposed to hot smoking produced oils with decreased oxidation and superior antioxidant potential, including higher levels of tocopherols, than their non-smoked counterparts. Smoking byproducts prior to oil extraction will extend the timeframe for oil removal and allow non-refrigerated transportation of oils without addition of costly antioxidants.

5. EFFECTS OF TEMPERATURE ON THE VISCOSITY and OXIDATION RATE OF UNPURIFIED SALMON OIL During oil purification it is important to be able to predict the apparent viscosity value of the oil at each step because each step involves exposing the oil to different temperature conditions. A study was conducted at Louisiana State University and University of Alaska to provide information on lipid oxidation as well as the thermal and rheological properties of unpurified salmon oil that are useful for designing improved purification processes of the oil. Results evaluated by ARS scientists at Fairbanks, AK indicated unpurified salmon oil exhibited non-Newtonian fluid behavior; the apparent viscosity decreased and the rate of lipid oxidation increased as temperature increased. The study showed that these changes could be competently described by the Arrhenius equation. These results are being used to design improved fish oil purification processes.

6. PURIFYING SALMON OIL USING ADSORPTION AND NEUTRALIZATION PROCESSES The quality of unrefined salmon oil decreases during storage. The development of simplified low cost procedures to remove pigments, proteins, moisture, free fatty acids and other impurities from unpurified oil will increase its quality and value. This study was completed by ARS scientists at Fairbanks, AK in cooperation with scientists at the University of Alaska, and Louisiana State University. Crude salmon oil was purified using activated earth adsorption, neutralization and a combination of both. The results indicated that combining adsorption technology with neutralization can provide an economical and simplified process for refining fish oil for human consumption. Information obtained in this study will assist in designing and building efficient adsorption units for purifying fish oils in a cost effective way.

7. ALASKA FISH BONE MEALS AS MINERAL SUPPLEMENT IN ALL-PLANT PRODUCT DIET FOR TROUT There is a potential market for Alaskan fish bone meals as feed ingredients in trout diets. A feeding trial was completed by the University of Idaho, University of Alaska and ARS scientists at Fairbanks, AK with post-juvenile rainbow trout fed all plant-product diets supplemented with Alaskan fish bone meal. Results indicated Alaskan bone meal produced an equivalent weight gain to fish fed the plant diet supplemented with dicalcium phosphate, but this weight gain was lower than that of fish fed a fishmeal control diet. The apparent bioavailability of phosphorus in the Alaskan bone meal was higher than that in fishmeal, but lower than dicalcium phosphate. This suggests that an effective mineral supplement can be produced from Alaskan fish bone meal with further processing.

8. ALASKA FISH TESTES MEAL SUPPLEMENTATION TO AN ALL-PLANT DIET FOR TROUT There is potential for making a feed ingredient from salmon testes. However, performance in feeding trials needs to be explored. In a study involving the University of Idaho, the University of Alaska and ARS scientists in Fairbanks, AK a feeding trial was completed with post-juvenile rainbow trout fed all plant diets supplemented with graded levels of Alaskan testes meal or fishmeal. The dose-response was recorded and measurable weight gain was observed with both testes meal and fishmeal supplementation. Fish fed all plant diets lacking either testes meal or fishmeal had significantly lower final weights than fish fed diets supplemented with these meals. This study supports the concept that all-plant diets for rainbow trout lack the constituents required for the substantial weight gain that are found in Alaska seafood byproducts, but further research is needed to identify these constituents.

9. NUTRITIONAL QUALITY OF NOVEL ALASKAN POLLOCK BYPRODUCT MEALS The nutritional value for Pacific threadfin (Polydactylus sexfilis) of Alaskan pollock bone, liver and milt meals was unknown. The Oceanic Institute, the University of Alaska and ARS scientists in Fairbanks, AK collaborated on a growth trial in which these three meals were included into a pollock fish meal based control diet at a 10% level. It was found that the threadfin fed diets containing the three meals grew at least as well as those on a pollock fish meal control diet. This information is useful because it indicates that there are no clear benefits in using fish Alaskan pollock bone, liver or testes meals over conventional fish meal for inclusion in diets for Pacific threadfin.

10. PALATABILITY OF ALASKA POLLOCK MEALS FOR SHRIMP The ability of various meals made from specific waste streams of the Alaska fishing industry (pollock milt and liver meals, bone meal and crab shell) to act as attractants for Pacific white shrimp was tested. The Oceanic Institute, the University of Alaska and ARS scientists in Fairbanks, AK participated in a study where the control diet containing wheat flour and soybean meal was replaced at the 5% level by one of the four test ingredients. Preferences of shrimp for the test diets relative to the control revealed that liver and crab shell meals acted as attractants, while milt and bone meals had no significant impact. A commercial shrimp feed, included as a positive control, also was consumed at a significantly higher rate than the wheat flour soy control. These results indicate that crab shell and liver meals may be used as feed attractants for this species of shrimp.

11. MODIFYING FISH GELATIN FILM PROPERTIES BY VARYING DRYING TEMPERATURES Gelatin films have been widely used to produce capsules for encasing drugs and have also been envisioned as packaging materials. ARS scientists in Fairbanks, AK examined the effects of drying temperature on the barrier and mechanical properties of Alaska pollock and Alaska pink salmon gelatin films. Cold-cast films (dried below gelation temperature) had superior tensile strength, but inferior water vapor permeability compared to hot-cast films. Therefore some of the material properties of fish gelatin films can be controlled by varying the drying temperatures. This provides an easy method to manipulate fish gelatin film properties to become more competitive with mammal based gelatin films.

12. CHARACTERISTICS OF BYPRODUCTS FROM BLACK ROCKFISH AND SKATES Black rockfish and skates are commercially harvested species in Alaska. A study was conducted by University of Alaska and ARS scientists in Fairbanks, AK to characterize black rockfish and skate byproducts. Byproducts obtained included frames, digestive tracts and livers from both species. Proximate fatty acid, amino acid and mineral compositions as well as fat soluble vitamin content were determined. Skate oils had high levels of long chain omega-3 fatty acids. Amino acid analysis revealed that byproducts from both species were good sources of essential amino acids. The research impacts fish processors by providing guidance on how byproducts from these species can be utilized for production of food and feed ingredients.

13. CROP YIELDS USING ALASKA BYPRODUCT ORGANIC FERTILIZERS Alaska fish waste has been made into fertilizers for a number of years. However, there is little published information on plant nutrient recovery and soil nutrient status at two or three years after the fish fertilizer application. Three fish byproducts (fish meal, fish bone meal, and fish hydrolysate) were evaluated in two different Alaskan locations for their nutrient release and barley growth response in 2007 and 2008 by the University of Alaska and ARS scientists in Fairbanks, AK. Significant amounts of nutrients (especially N) were released in the second year after their application, but in the third year, there was little impact from these application on barley growth. These results suggested a reduced application rate of fish byproduct fertilizer can be used in the second year, and this will help producers managing such fertilizers for crop production.

6.Technology Transfer


Review Publications
Bower, C.K., Hietala, K.A. 2008. Acidification Methods for Stabilization and Storage of Salmon By-Products. Journal of Aquatic Food Product Technology. 17:459-478.

Bower, C.K., Hietala, K.A., Oliveira, A., Wu, T.H. 2009. Stabilizing Oils from Smoked Pink Salmon (Oncorhynchus gorbuscha). Journal of Food Science. 74(3):C248-C257.

Sathivel, S., Bechtel, P.J. 2008. A comparison of physical and rheological properties of Arrowtooth Flounder protein made using three different extraction processes. Journal of Food Biochemistry. 32:557-575.

Reppond, K., Oliveira, A., Bechtel, P.J. 2009. Enzymatic Digestion of Eye and Brain Tissues of Sockeye and Coho Salmon, and Dusky Rockfish Commercially Harvested in Alaska. Journal of Aquatic Food Product Technology. 18(3):209-222. Available:

Oliveira, A., Bechtel, P.J., Morey, A., Demir, N. 2009. Composition of Heads and Livers of Yelloweye Rockfish (Sebastes ruberrimus) Harvested in Alaska. Journal of Aquatic Food Product Technology. 18:53-66.

Sathivel, S., Yin, H., Bechtel, P.J., King, J.M. 2009. Physical and Nutritional Properties of Catfish Roe Spray Dried Protein Powder and its Application in an Emulsion System. Journal of Food Engineering. 95(1):76-81. Available:

Bechtel, P.J. 2003. Properties of Different Fish Processing By-Products From Pollock, Cod and Salmon. Journal of Food Processing and Preservation. 27(2):101-116.

Wu, T.H., Bechtel, P.J. 2009. Quality of Crude Oil Extracted from Aging Walleye Pollock (Theragra chalcogramma) Byproducts. Journal of the American Oil Chemists' Society. Available:

Bower, C.K. 2007. Post Harvest Handling, Storage, and Treatment for Fresh Market of Berry Fruit. In: Zhao, Y., Editor. Berry Fruit: Value-Added Products for Health Promotion. Boca Raton, FL: CRC Press, Taylor & Francis Group. p. 261-288.

Bechtel, P.J. 2007. By-products from seafood processing for aquaculture and animal feeds. In. Shahidi, F., editor. Maximising the Value of Marine By-Products. Cambridge, England. Woodhead Publishing Ltd. pp. 435-449.

Sathivel, S., Bechtel, P.J. 2007. Engineering and functional properties of protein powders from underutilized marine fish and by-products. In Shahidi, F., editor. Maximising the Value of Marine By-Products. Cambridge, England. Woodhead Publishing Ltd. pp.250-257.

Last Modified: 10/25/2014
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