Development of smoked fish sausage from Alaskan pink salmon
Naim Montazeri, Huseyin Biceroglu, Katie Brenner, Stuart Thomas, Matthew Davenport
Charles Crapo, Brian Himelbloom & Alexandra Oliveira
Fishery Industrial Technology Center, School of Fisheries and Ocean Sciences
University of Alaska Fairbanks, Kodiak AK 99615
Abstract
Pink salmon (Oncorhynchus gorbuscha) is the most abundant Pacific salmon harvested in Alaska. Pinks are a low cost protein-rich muscle food suitable for producing value-added products. We formulated salmon sausages using edible salmon and coconut oils (1:1) as emulsifiers, and oatmeal as a texture enhancer. Fresh and smoked
sausages were produced using a traditional process (a 5 h smoking process was carried out until the core temperature reached 71.1°C under controlled humidity of 40%). Products were analyzed for proximate composition, fatty acid profiles, free fatty acid content, salt content, color, shear force, protein molecular weight via SDS-PAGE, and
total microbial counts. Smoking significantly (P<0.05) changed water content (from 69 to 63 %), protein (from 21 to 22%), lipid (from 5 to 6%), carbohydrate (from 4 to 5%), ash (from 2 to 3%), whiteness (from 61 to 58), Kramer shear force (from 450 to 1200 g/g) and microbial count (from 4.1 log CFU/g to <2 log CFU/g). Salt content (averaged
1.2%) and fatty acid profile did not significantly change (P>0.05). Smoked sausages contained high levels of PUFA (776 mg) with high concentrations of EPA (160 mg) and DHA (322 mg) per serving size of smoked sausage. Water-soluble proteins constituted a small portion of total proteins in the smoked sausage. SDS-PAGE showed that the
250 kDa myosin heavy chain bands were visible but proteins greater than 75 kDa constituted the major portion of bands on the gel dominated by 250 kDa (heavy chain myosin). Fresh and smoked salmon sausages are rich omega-3 fatty acids, protein and show potential for introduction to consumers seeking healthier alternatives to
terrestrial animal products.
Introduction
Pink salmon (Oncorhynchus gorbuscha), also known as humpy, are the smallest Pacific salmon in North America with
averaging weight and length of 1.5-2.5 kg and 50-65 cm, respectively. The most abundant of the Pacific salmon species in
Alaska, with average yearly catches at about 100 million fish, pinks have low commercial value when compared to chum,
sockeye, coho, or king salmon. A large portion of the pink salmon harvested in Alaska is still processed into cans, but
market demand for frozen fillets has increased in recent years.
During spawning migration, the lipid content of salmon muscle decreases, with a concomitant increase in water
content, resulting in muscle softening. Simultaneously to a decrease in lipid content is the development of skin
watermarking, which occurs due to migration of the lipid soluble carotenoids from the muscle to skin (pale-meat salmon).
Overall, watermarked salmon (dark fish) tends to yield edible muscle with lower nutritional value as it compares to bright
fish (Lapis, 2010). Thus, through the season lipid content in pinks are highly variable. Edible salmon oil, easily recovered
from the lipid-rich pink salmon heads (~15-20% lipids), may be added to certain pink salmon products thereby increasing
the lipid content and decreasing variability in the lipids (Lapis et al., 2010). As an example, recent research conducted at
FITC (SFOS/UAF) has demonstrated that adding salmon oil to canned pale-meat pink salmon significantly improves the
nutritional value of the product (Lapis, 2010).
Despite the highly variable range of lipid content recorded for pink salmon (2-9%; Hardy and King, 1989); the lipids in
this species are rich in ω-3 fatty acids (~30%). Therefore, pinks are a good source of long-chain polyunsaturated fatty acids
such as DHA (docosahexaenoic acid; 22:6w3) and EPA (eicosapentaenoic acid; 20:5w3), also being rich in high quality
protein. Pinks are a nutritious food source that due to its lower market value can be used as raw material for the
production of value-added products such as sausage.
The overall goal of this research was to develop a nutritionally-rich and shelf-stable fish sausage using pale-meat
pink salmon as the principal ingredient. Salmon and coconut oil were used as lipid sources and served as emulsifiers.
Salmon oil was chosen because it improves the nutritional value of the finished product by boosting DHA and EPA levels.
Oatmeal was used as a natural texture enhancer, while smoking served as a preservative step that improves product shelflife and adds desirable flavor to muscle foods.
Smoked
salmon sausage
Grind
boneless
skinless
fillets
Add salt &
phosphate
Tumble
13 min
Fresh salmon
sausage
Add
flavorings
Tumble 3 min,
add water &
tumble 4 min
Add
salmon oil &
coconut oil
Smoking
Tumble
5 min
Ground Pink Salmon Meat
NaCl
Phosphate salts
Black Pepper
Brown Sugar
Dried Dill Weed
Dried Nutmeg Powder
Dried Ginger Powder
Dried Garlic Powder
Water
Purified Salmon Oil
Extra Virgin Coconut Oil
Oatmeal
Weight (g)
Sources
8,200
88
36
62
41
25
12
6
6
900
220
220
420
Wild caught, AK
Cargill (Minneapolis, MN)
BK Giulini Corp. (Simi Valley, CA)
McCormick (Hunt Valley, MD)
C&H Sugar Company, Inc. (Crockett, CA)
Signature Food Serv. Amer. (Seattle, WA)
Safeway (Pleasanton, CA)
Safeway (Pleasanton, CA)
McCormick (Hunt Valley, MD)
Cold tap water
Alaska Protein Recovery (Juneau, AK)
Nutiva Organic (Sebastopol, CA)
Quaker Oats Old Fashioned (Chicago, IL)
Components (% mean ± SD)
Protein
Lipid
Carbohydrate
Moisture
Ash
Hand mix
oatmeal
Figure 1. Flowchart of sausage processing
FS (n=3)
21.3a ± 0.6
5.2a ± 0.5
4.2a ± 0.1
69.0a ± 0.1
2.3a ± 0.0
SS (n=3)
22.4b ± 0.8
5.9b ± 0.3
5.5b ± 0.3
63.0b ± 0.1
2.7a ± 0.0
Numbers in a row with different letters are significantly different (p < 0.05). Values are
mean (%) ± SD; n=3, FS (Fresh sausage), SS (Smoked Sausage).
Table 3. Summary fatty acid profiles and free fatty acid values
mg/g oil
1
2
3
4
5
6
7
Figure 2. SDS-gel of smoked sausage. 1: Total
protein 10ml; 2: Water soluble 10 ml; 3: Salt
soluble 10 ml; 4: Salt soluble 5 ml; 5: Water
soluble 5 ml; 6: Total protein 5 ml; 7: Standard 5
ml
Shear Force Results of Fresh vs Smoked Sausages
Shear force (g g muscle -1)
Processing: Frozen dressed pink salmon were filleted and ground using a Cabela’s meat grinder (Sidney, NE), equipped with
7 mm plate. Ingredients were mixed and tumbled in a Holly 50 vacuum tumbler (Hollymatic®, IL). The meat was stuffed
(Fdick; Germany) into collagen casings (24 mm) and sausages divided into links. Then, the links were smoked (final core
temperature of 71 °C at 40% humidity) in an Enviro-Pak Model C4-150 smoker (Clackamas, OR). Ingredients are shown in
Table 1. Sausage production procedure is illustrated in Figure 1.
Chemical analysis: Moisture and ash content were determined using 952.08 and 938.08 methods, respectively (AOAC,
1990). Crude lipid was determined using Folch et al. (1957). Protein content was measured with a nitrogen analyzer (LECO,
St. Joseph, MI). Salt content was measured using a Nelson Chloride Analyzer 926 (Turlock, CA). Fatty acid methyl esters
(FAMEs) were prepared and quantified according to Maxwell and Marmer (1983). Free fatty acids content was determined
using method Ca-5a-40 (AOAC, 2004). Carbohydrate content was determined by subtraction.
Color and texture: Minolta-Chroma meter CR-400 colorimeter (Minolta CO., Ltd., Osaka, Japan) was used for determination
of tristimulus color values. The whiteness was calculated as “Whiteness = 100 – [(100-L*)2+a* 2+b*2]1/2” following Taskaya et
al. (2009). Texture analyzer (TA-HDI) was used to determine Kramer shear force of the sausage links.
SDS-PAGE: Gel electrophoresis was used to separate proteins by molecular weight and images were taken with a Versa Doc
System (Model 1000 Bio-Rad Imaging System, CA).
Microbiological Analysis: Total mesophilic bacteria were enumerated in serially diluted samples and were reported as log
CFU/g.
Statistical Analysis: Statistical analyses were conducted using ANOVA and Tukey’s HSD test (p < 0.05, Statistica 9.1, Tulsa,
OK).
Ingredients
The process yielded 64 sausage links from a total of 10.2 kg mixture (160 g each link)
Smoking process significantly reduced the moisture content and increased protein, lipid and carbohydrate content of
the sausages (Table 2)
NaCl content was 1.1 ±0.1% in the fresh sausage increased to 1.3± 0.0% after smoking.
No significant differences found in free fatty acid profiles between SS and FS (p > 0.05).
Levels of PUFA were 775 mg (in 85 g serving size) higher than recommended 650 mg daily intake (Simopoulos et al.,
1999) and are reported in Table 3.
The mean mesophilic bacterial count in FS was 4.1 log CFU/g that was lowered to less than 2 log CFU/g following
smoking.
The SDS-PAGE (Figure 2) shows that proteins heavier than 75 kDa constituted the major portion of total protein
dominated by 250 kDa (heavy chain myosin). Texture significantly increased by smoking process (Figure 3)
Whiteness and lightness was reduced by smoking (Table 4), likely due to the browning (formation of products from
Maillard reaction, and Amadori rearrangements). Redness (a*) and yellowness did not change significantly (p >
0.05).
Table 2. Proximate composition of fresh and smoked fish sausages
Material and methods
Table 1. Pink salmon sausage ingredients in order of addition to formulation
Results
1400
1300
1200
1100
1000
900
800
700
600
500
400
300
Lauric acid (C12:0)
Palmitic acid (C16:0)
Oleic acid (C18:1 ω-9 cis)
Σ SAT
Σ MUFA
Σ PUFA
Σ ω-3 FA
EPA
DHA
FFA
SS (n=3)
FS (n=3)
CO (n=3)
SO (n=3)
110.5a ± 6.9
71.9a ± 3.9
55.5a ± 2.5
279.6a ± 16.5
195.9a ± 11.3
154.2a ± 7.6
129.3a ± 6.5
112.8a ± 7.7
71.4a ± 4.0
54.5a ± 2.9
282.1a ± 18.4
190.9a ± 11.1
154.2a ± 8.2
129.8a ± 6.6
476.4 ± 23.3
84.9 ± 3.8
49.7 ± 2.2
843.1 ± 40.5
49.7 ± 2.2
7.7 ± 0.3
0.0 ± 0.0
0.00 ± 0.0
56.5 ± 1.4
42.2 ± 1.0
99.6 ± 2.4
244.5 ± 6.1
163.7 ± 3.8
146.9 ± 3.5
31.8a ± 1.4
64.0a ± 3.7
8.6
32.0a ± 1.2
64.7a ± 3.1
8.2
0.0 ± 0.0
0.0 ± 0.0
0.1
43.5 ± 1.0
54.7 ± 1.3
0.3
Numbers in a row with different letters for SS and FS are significantly different (p < 0.05)., FS (Fresh
sausage), SS (Smoked Sausage), CO (Coconut oil) and SO (Salmon Oil); FA fatty acid; SAT saturated FA; MUFA
monounsaturated FA; PUFA polyunsaturated FA; ω-3 omega-3 FA; FFA free fatty acids
a
Table 4. Tristimulus color and whiteness values
L* (lightness)
b
SS
FS
Treatment
Figure 3. Kramer test; SS (smoked sausage); FS (fresh sausage)
References
AOAC, 1990. Official methods of analysis, 16th Edition. Association of Official Analytical Chemists. Arlington, VA.
AOCS. 2004. Official methods and recommended practices of the American Oil Chemists Society. 5th. AOCS Inc.
Champaign.
ADF&G (Alaska Department of Fish and Game) 2011, Salmon Fisheries in Alaska, Harvest and Species Overview. Website:
http://www.cf.adfg.state.ak.us/geninfo/finfish/salmon/salmon_harvest.php
Folch J, Lees M, Sloane and Stanley GH, 1957. J. Biol. Chem. 226. pp. 497-509.
Hardy RW, and King, IB. 1989. Omega-3 News. 4, 1-4.
Lapis TJ. 2010. Improving the sensorial and nutritional attributes of canned Alaska pink salmon (Oncorhynchus
gorbuscha) With salmon oil. MS thesis in Seafood Science and Nutrition. University of Alaska Fairbanks. 131p.
Lapis TJ, Oliveira ACM, Himelbloom BH, Bechtel PJ, and Crapo CA. 2010. J. Food Sci. (under publication)
MaxwelL RJ., and Marmer WN. 1983. Lipids. 18. pp. 453-459.
Taskaya L, Chen YC, Beamer S, and Jacyznski J. 2009. J. Sci. Food Agric. 89. pp. 349-358.
SIMOPOULOS, AP, LEAF A, SALEM N Jr. 1999. Ann. Nutr. Metab. 43:127-130
a* (redness) b* (yellowness)
Whiteness
FS (n=3)
69.0a ± 1.9
1.1a ± 0.8
23.1a ± 1.1
61.2a ± 1.0
SS (n=3)
64.7b ± 2.8
0.9a ± 0.6
23.4a ± 1.0
57.6b ± 2.4
Numbers in within a column with different letters are significantly different (p < 0.05)
Discussion
In this study, a low-salt and nutritious fish sausage (rich in ω-3 fatty acids) was developed. Salmon oil
and coconut oil were successfully used as the oil sources and improved nutritional quality and the
flavor of the sausages. Smoking process enhanced textural quality and shelf life stability of the final
product by lowering bacterial load with no negative effect on fatty acids profile. Watermarked pink
salmon can be viable substitute to terrestrial meat sources. Economic feasibility of the process and
sensory analyses should be assessed before initiating large scale production.
This research was conducted during Spring 2010 semester as part of
FITC graduate course FSN 672 ‘Laboratory Methods in Food Sciences’
Kodiak Area Marine Science Symposium, April 9–12, 2011