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United States Department of Agriculture

Agricultural Research Service

Research Project: ALASKA FISH PROCESSING BYPRODUCTS
2011 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 byproducts as food and feed ingredients in a sustainable manner. This will be achieved by accomplishing the three listed objectives. 1. Develop new and improved feed ingredients and high value human food products using fish processing co-products. 2. Develop economical processes and methods for the collection, stabilization and storage of raw seafood byproducts to optimize their chemical, nutritional, and physical qualities for uses including food and feed ingredients, fertilizers and bio-chemicals. 3. Develop ingredients from fish processing co-products that meet larval and stage specific physiological requirements of marine fish when used in modern dietary formulations.


1b.Approach (from AD-416)
Fractions prepared from pollock and salmon byproducts such as fish meals, hydrolysates and stick water will be identified that promote growth in targeted aquaculture species fed plant protein based diets. Also, aquaculture ingredients from fish byproducts such as enriched fatty acid and phospholipid fractions will be identified that increase performance in targeted species. A continuous system for purifying and stabilizing salmon and pollock oils extracted from byproducts will be developed that can be used in smaller rural processing plants. Machine vision systems will be developed that can identify individual byproduct components such as liver and then efficiently separate the parts for further processing or packaging. Processes will be developed that improve the functional properties of fish skin gelatin films and other gelatin products in collaboration with scientists at WRRC in Albany, CA. Constituents of testes and other meals that positively affect shrimp and fish growth will be identified for use as aquaculture ingredients. The minimum levels of dietary omega 3 fatty acids required to sustain good growth and health of trout at different life stages will be determined. Economic analyses of the cost effectiveness of different methods of handling seafood processing byproducts will be provided to stakeholders. Collaborative studies between ARS and University of Alaska scientists will be conducted in the pilot plant and laboratories in Kodiak and Fairbanks, AK, and feeding trials will be conducted at the University of Idaho and the Oceanic Institute in Hawaii. Replacing 5341-31410-003-00D (10/09).


3.Progress Report
Significant progress has been achieved by USDA-ARS scientists in Kodiak, AK and their cooperators in four primary areas of study that include.
1)fish byproduct chemistry and characterization,.
2)byproduct processing,.
3)stabilizing byproducts and evaluating quality during storage, and.
4)aquaculture and other animal trials. In the areas of byproduct chemistry, salmon oils were extracted and evaluated over the entire harvest season. These studies showed that oil quality remained high and were free from critical pollutants such as organo-chlorine pesticides and Polychlorinated Biphenyls(PCBs). Additionally, a new adsorption column process was developed that used activated earth and alumina to purify salmon oil, and a new liquid chromatography mass spectrometry (LC/MS) method was developed to quantify low molecular weight nitrogen compounds in fish processing stickwater. A new method using a color shift in the biuret reagent has also been developed following hydrolytic reactions. New and on-going work is underway to help stabilize and evaluate new fish byproducts including studies to extend the storage life of acidified pollock fish processing mince, and extend the storage life of salmon oils and meal for periods of up to a year, are being conducted. A further fish byproduct utilization study is being completed to assess the affect of fish compost on crop yields for barley, potato and kale. The first year of a two-year study on the impact of fish byproducts has now been completed and the second year planned. In the area of fish byproduct processing, new methods are being studied to develop processing parameters for optimizing the quality of dried salmon, pollock and cod heads for the export market. Other on-going studies include the fractionation of stickwater and hydrolysates using pressurized membrane filtration units, and the application of image analysis methods to predict weight of pollock roe and salmon. Clean bone matter was obtained from both salmon and whitefish, and detailed chemical composition was determined, including characterization of the mineral contents from these species. Additionally, a study on UV cross-linking of gelatins from warm and cold water fish was completed, as was an economic analysis of low cost methods of making high quality fish oil from salmon heads. In the area of aquaculture and other animal feeding trials, the nutritional quality of salmon testes-meal for Pacific threadfins and shrimp was conducted, and a study on the satiety of dogs fed diets containing salmon and pollock muscle protein was completed. Omega 3 fatty acid dietary requirements were also assessed for fingerling stages of rainbow trout and it was determined that fish oils could replace fish meal in many situations with no signs of fatty acid deficiencies. Also, a study was completed on the effects of holding Alaskan commercial salmon meals and oils at different temperatures for periods of up to one year. These studies along with a nutritional study on the use of pollock viscera meat in the diets of striped, sunshine and largemouth bass was completed with cooperators, and other studies as outlined in the Project Statement are being developed.


4.Accomplishments
1. High value, low molecular weight nitrogen compounds in stickwater and other fish processing byproducts. Increasing evidence suggests that the water soluble - low molecular weight fractions of marine protein sources are important for the performance of aquacultured fish. A study was conducted by USDA/ARS scientists in Kodiak and Fairbanks, AK, to evaluate some of these soluble low molecular weight compounds in stickwater (SW) made from pollock processing byproducts. Samples were prepared for direct analysis by mass spectrometry without derivatization. A new method was developed for screening low molecular weight compounds that revealed inosine, creatin, creatinine, trimethyl amine, and trimethyl amine in pollock stickwater samples. This is important to industry as it provides a new and rapid method to assess chemical composition of fish byproducts.

2. Assessment of salmon head parts for nutrient and oil levels. Alaska processes the largest volume of wild caught salmon in the US and a common method of processing salmon is to head and gut the fish. Many rural Alaskan processors merely grind and dump their processing waste, a process allowed by state and federal regulators with certain restrictions; however, there is the potential to create value-added products from portions of these salmon heads. A study was conducted by USDA/ARS scientists in Kodiak, AK, to examine red salmon (Oncorhynchus nerka) head parts to better understand their lipid composition and the distribution of nutrients in braincases, soft tissue, gills and face halves. Braincases had the highest lipid and lowest protein content, gills had the lowest lipid, and soft tissue had the highest protein content, while amino acid analysis showed small concentration differences in methionine, phenylalanine, and arginine. The fatty acid profiles of all four parts were not markedly different from each other and were similar to oils extracted from other salmon or salmon byproducts suggesting that red salmon heads could be used as a low-cost raw material for both food and feed ingredients.

3. Low cost enzymatic hydrolysis of salmon heads: an economic feasibility analysis. A study was conducted by University of Alaska scientists in collaboration with a USDA/ARS scientist in Kodiak, AK, to provide an economic feasibility analysis on a low cost method of making protein and oils from salmon heads using equipment present in many small salmon processing facilities. Numerous industry members were interviewed to obtain required operational information regarding the methods used to recover crude salmon head oil. Cost information covering equipment, labor, facility costs, energy use, etc., were obtained and a break-even analysis conducted. Results were compared to the commercial alternative of Number Two diesel in Southeast Alaska. Preliminary results show that a five year break-even price for a salmon head oil extraction facility with the capacity of processing 450MT of heads per year came to USD $14.93 as opposed to $1.64 per liter for Number 2 diesel. This analysis will be used as the basis for discussions with seafood processors in Southeast Alaska and eliciting their guidance regarding subsequent economic analyses.

4. Substitution of Alaskan pink salmon testes meal for fish meal in feed for Pacific threadfin. This study evaluated the growth parameters of different level of testes meal, when added to plant protein based diets. Scientists from The Oceanic Institute in collaboration with University of Alaska and USDA/ARS scientists in Kodiak, AK, conducted an eight week growth trial using Pacific threadfin (Polydactylus sexfilis). Five semi-purified formulations were developed to contain the same lipid and protein levels using soybean meal, pollock meal and/or pink salmon testes meal, while a commercial diet containing 14% lipid and 50% protein was used as reference. The results of this study suggest that optimal replacement of pollock protein meal with salmon testes meal is dose dependent and supplementation at a level of 6% salmon testes meal was optimal for juvenile Pacific threadfin based on feed utilization, growth performance and the nutritional quality of fish.

5. Omega-3 fatty acid requirement of rainbow trout fingerlings. Dietary fatty acid requirements of salmon and trout are being conducted by scientists at the University of Idaho in collaboration with University of Alaska and USDA/ARS scientists on stage-specific differences in rainbow trout omega-3 fatty acid dietary requirements. A 16-week feeding trial was completed with juvenile rainbow trout fed experimental diets totally lacking fish meal and containing varying amounts of Alaskan fish oil and canola oil. No clinical signs of omega-3 fatty acid deficiency were observed and trout fed diets containing 0.34-0.92% omega-3 fatty acids did not differ in final fish weight, but fish fed the highest level of dietary omega-3 fatty acids had significantly different weights compared with trout fed the lowest dietary level. These results conflict with previously reported dietary requirements using nutritionally-incomplete diets and should be important in developing new diet alternatives.

6. Purification of salmon fish oil using a pilot scale adsorption column. An economically viable purification method is needed to remove impurities from unpurified salmon oil (USO) without changing the desirable fatty acid composition. A study by scientists at Louisiana State University in collaboration with USDA/ARS and University of Alaska scientists in Kodiak, AK, was initiated to develop an adsorption column process for purifying salmon oil. USO and purified salmon oil samples were analyzed for fatty acid profiles, peroxide values, free fatty acids, moisture content and rheological properties. This study demonstrated that the column adsorption process effectively reduced peroxide values, free fatty acids, and moisture content of salmon oil, which will improve the purification process for industry.

7. Characterization of bone from red salmon, Pacific cod and Alaskan polock frames. In Alaskan commercial fisheries, large volumes of skeletal frames are produced from pollock, cod and salmon, and can be used to make fish meal or further processed into food by removing remaining muscle tissue attached to the ribs and spinal column. A study was conducted by USDA/ARS and University of Alaska scientists in Kodiak, AK, to evaluate the composition, amino acid profile and mineral content of the major sources of bone from wild marine species harvested in Alaska to develop new uses for fish byproducts. Fresh Pacific cod, red salmon and Alaska pollock frames were collected from commercial processors and batches of bone were processed from the frames of each species. There were large differences in the composition of bone from different north Pacific fish species with cod and pollock bone both composed of approximately 65% ash, 30% protein and little lipid, while red salmon bone was 35% protein, 8.5% lipid and 55% ash. These results suggest that there is potential for increasing the utilization of marine fish bone as a nutritional supplement, feed ingredient or in the sequestration of toxic heavy metals in soils.

8. Satiety in dogs fed salmon and pollock protein. Satiety is an important factor in controlling obesity and fish proteins have been reported to be more satiating than meat proteins. A study was conducted by scientists at the University of Illinois in collaboration with USDA/ARS and University of Alaska scientists in Kodiak, AK, to evaluate muscle proteins from fish with other muscle proteins on satiety in dogs. The study evaluated the effect of beef, chicken, pork, or fish protein pre-meals on postprandial satiety hormone and 24 h food intake responses. Results showed that blood glucose decreased over time but was lowest when dogs were fed pollock or chicken substrates, and that food intake tended to be greater when dogs consumed the beef pre-meal compared to when dogs consumed the pork or pollock pre-meals. Thus, protein source appears to influence blood markers of satiety in dogs, but has little effect on decreasing overall food intake. This study is important as it may lead to new food products in the fisheries industry.

9. Chrondroitin sulfate from fish. Chondroitin sulfate is taken orally by many individuals to help alleviate pain from arthritic joints, thus there is potential to increase the value of fish processing byproducts by extracting chondroitin sulfate from fish connective tissues. Therefore, a study was conducted by USDA/ARS scientists in Kodiak, AK, to determine chondroitin sulfate content in the different tissues of different salmon heads. Analytical techniques were adapted to determine chondroitin sulfate content in the heads of different salmon species and in fractions from red salmon heads. The fraction of the red salmon head that contain the highest concentration of chondroitin sulfate was the connective tissue rich snout and braincase, or if from male salmon the exaggerated kype, with 34 mg/g total chondroitin sulfate (dry weight basis). The levels of chondroitin sulfate in salmon heads appear to be sufficient to be used for the cost-effective extraction of chondroitin sulfate suggesting that extraction of chondroitin sulfate from fisheries byproducts is possible and may result in new value-added products.

10. Ultraviolet B light-induced crosslinkage to improve physical properties of cold and warm water fish gelatins. Gelatin is widely applied in food industry to produce thermo reversible gels that melt in the mouth. Fish skin gelatin is a feasible alternative to mammalian gelatins but has a lower gel strength, that limits its commercial application. Collaborating scientists at the USDA/ARS laboratories in Albany, CA, and Kodiak, AK, embarked on studies to alter the physical properties of both cold and warm water fish skin gelatins using UV-B light, and then evaluated the effect of multiple doses of light on gel strength, rheological, tensile, and water vapor barrier properties of both cold-water and warm-water fish gelatins. Treated samples displayed higher gel strength than control and UV-B treatment improved the gel strength with cold water gelatin showing the greatest gel strength increase (52%). These results demonstrate a potential use of UV-B light treated fish gelatin for food applications, eliminating concerns regarding food safety while maintaining functional properties and quality.


Review Publications
Wu, T.H., Nigg, J.D., Stine, J.J., Bechtel, P.J. 2011. Nutritional and chemical composition of by-product fractions produced from wet reduction of individual red salmon (Oncorhynchus nerka) heads and viscera. Journal of Aquatic Food Product Technology. 20(2):183-195.

Bower, C.K., Malemute, C., Bechtel, P.J. 2011. Endogenous protease activity in byproducts of pink salmon (Oncorhynchus gorbuscha). Journal of Food Biochemistry. DOI:10.1111/j.1745-4514.2010.00406.

Wu, T.H., Stine, J.J., Bechtel, P.J. 2011. Preliminary chemical and nutritional characterization of liver from longnose skates (Raja rhina). Journal of Food Composition and Analysis. 24(3):356-361.

De Santos, F.A., Ramamoorthi, L., Bechtel, P.J., Smiley, S., Brewer, S. 2010. Effect of salmon type, and presence/absence of bone on color, sensory characteristics, and consumer acceptability of pureed and chunked infant food products. Journal of Sensory Studies. 75(6):S279-S285.

Oliveira, A., Bechtel, P.J., Lapis, T., Brenner, K., Ellingson, R. 2011. Chemical composition of black rockfish (Sebastes melanops) fillets and byproducts. Journal of Food Processing and Preservation. 35(4):466-473.

Stone, D.A., Oliveira, A.C., Ross, C.F., Plante, S., Smiley, S., Bechtel, P.J., Hardy, R.H. 2011. The effects of phase-feeding rainbow trout (Oncorhynchus mykiss) with canola oil and Alaskan pollock fish oil on fillet fatty acid composition and sensory attributes. Aquaculture Nutrition. 17(2):e521-e529.

Stone, D.A., Oliveira, A.C., Plante, S., Smiley, S., Bechtel, P.J., Hardy, R.W. 2011. Enhancing highly unsaturated omega-3 fatty acids in phase-fed rainbow trout (Oncorhynchus mykiss) using Alaskan fish oils. Aquaculture Nutrition. 17(2):e501-e510.

Vester Boler, B.M., Faber, T.A., Bauer, L.L., Swanson, K.S., Smiley, S., Bechtel, P.J., Fahey, G.C. 2012. Accute satiety response of mammalian, avian and fish proteins in dogs. British Journal of Nutrition. 107:146-154.

Last Modified: 7/31/2014
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