Waste Biomass Valor DOI 10.1007/s12649-016-9710-2
ORIGINAL PAPER
Quality Properties and Bio-potentiality of Edible Oils from Atlantic Salmon By-products Extracted by Supercritial Carbon Dioxide and Conventional Methods Monjurul Haq1,2 • Raju Ahmed1 • Yeon-Jin Cho1 • Byung-Soo Chun1
Received: 31 March 2016 / Accepted: 21 September 2016 Ó Springer Science+Business Media Dordrecht 2016
Abstract Fish processing industries produce a large amount of by-products every year which are just dumped or used for less productive purposes. This paper instructs the approaches for the production of edible oils from Atlantic salmon byproducts for value addition of fish wastes and meeting the increased demand of omega polyunsaturated fatty acids. Atlantic salmon by-products (belly part, trimmed muscle, frame bone and skin) oils extracted by supercritical carbon dioxide (SC-CO2) and n-hexane were compared with belly part oil (PBePO) obtained from traditional pressing. Oil extracted by n-hexane, was considered as total oil and the yield was higher amongst with 45.46 ± 0.57–49.26 ± 0.90 %, followed by SC-CO2 and pressed oil with 76.12 ± 1.02–86.99 ± 1.14 and 61.83 ± 0.0.84 % (of total oil, dry matter basis), respectively. SC-CO2 extracted oils showed attractive color and better viscosity property than PBePO and n-hexane extracted oil. The acid value, peroxide
value and free fatty acid value of PBePO were lowest (6.29 ± 0.32, 0.97 ± 0.12 and 2.37 ± 0.19 respectively) followed by SC-CO2 (7.48 ± 0.62–8.03 ± 0.35, 1.10 ± 0.2–1.25 ± 0.14 and 3.23 ± 0.31–3.89 ± 0.40 respectively) and n-hexane (10.28 ± 1.25–11.03 ± 0.52, 1.36 ± 0.28–1.68 ± 0.20 and 4.08 ± 0.22–4.74 ± 0.18 respectively) extracted oils. p-Anisidine value and total oxidation value of SC-CO2 extracted oils were significantly (P \ 0.05) lower than PBePO and n-hexane extracted oils. SC-CO2 extracted oils displayed higher radical scavenging activity and longer oxidative stability period (1.37 ± 0.03–2.14 ± 0.03 h). There was no significance difference in fatty acid compositions among the extracted oils. Extraction of edible oil by SC-CO2 from fish by-products may play a key role for obtaining financial benefits, nutrition and reducing environmental pollution.
& Byung-Soo Chun
[email protected] 1
Department of Food Science and Technology, Pukyong National University, 45 Yongso-ro, Nam-Gu, Busan 48513, Republic of Korea
2
Department of Fisheries and Marine Bioscience, Jessore University of Science and Technology, Jessore 7408, Bangladesh
123
Waste Biomass Valor
Graphical Abstract
SC-CO2 extraction
Yield
Temperature: 45°C Pressure: 250 bar Extraction time: 3 h CO2 Flow: 27g/ min
Stability (Acid value, Peroxide value, FFA value, p-Anisidine value, Total oxidation value, Rancimat test
Extracted oils a. SC-CO2 extracted b. Pressed c. Hexane extracted
Radical scavenging activity (DPPH, ABTS, FRAP, OH-) Time: 20 h, Temp: 45ºC RPM: 300
150 100 50
a d c eb g f ef g g f h i
0 PBePO SCBePO SCTMO SCBO SCSO HBePO HTMO HBO HSO Trolox Ascorbic acid BHA BHT
Samples: a. Belly part b. Trimmed muscle c. Bone d. Skin
Physical parameters (Color and viscosity)
Oils and antioxidants
Sample: solvent=40:200 (W/V)
Hexane extraction
Keywords Quality Bio-potential Atlantic salmon Edible oil SC-CO2
Introduction Salmon is a widely distributed fish and salmon consumption is considered to be healthy because of its high content of protein and omega polyunsaturated fatty acids as well as being a good source of minerals and vitamins. Atlantic salmon highly preferred by the consumers, is used for producing a variety of products such as smoked, fresh, sushi, as well as ready-made meals. Fish slaughtering and filleting operations lead to large amounts of offal consisting of viscera, heads, trimmings, skin and frame bones which may represent up to 46 wt% [1]. The present applications of fish by-products are in farmed organisms as feed ingredients, as organic fertilizers in agricultural fields, and studies on the possibility of using as biodiesel is going on
123
Fatty acid composition (GC Analysis)
but there is a huge scope of using as human food grade oil and polyunsaturated fatty acids (PUFA) supplement. Fish oils are one of the major sources of long chain PUFAs including cis-5,8,11,14,17-Eicosapentaenoic acid (EPA) and cis-4,7,10,13,16,19-Docosahexaenoic acid (DHA) [2]. These PUFAs especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) play a crucial role in the prevention of atherosclesis, heart attack, depression, stroke, diabetes, obesity, premature ageing, hypertension, cancer and improve the vision power and memory [3]. Decreased rates of cardiovascular disease have been noted in populations with high fish consumption, such as Alaskan natives [4, 5] and the omega-3 fatty acids are believed to be associated with these health benefits [6]. High levels of DHA are found in brain tissue and DHA is essential during brain development and retina formation of infants [7]. Atlantic salmon contains 2–15 % fat and 57 % of the total body fat is present in the inedible portion [8]. Due to increasing the number of health concerned people, the
Waste Biomass Valor
demand for fish oil is increasing day by day. The various by-products obtained from the Atlantic salmon can be used for providing high quality fish oil and PUFA supplement for meeting the increased demand. After extracting the lipid part, the residues of high protein concentrate (HPC) can be used as the previously mentioned fields. The by-products of Atlantic salmon possess an abundant and relatively underexploited source of oil which can be used as a concentrated polyunsaturated fatty acid source for human diets, including pets. Moreover, astaxanthin in salmon oil is associated with reduced risk of diseases such as age-related macular degeneration and ischemic diseases, effects attributed to its potent antioxidant activity [9]. Traditionally, fish oil has been produced from by-catch and fish specifically caught for fish meal and oil production [10]. At present the limit of how much wild fish can be captured without affecting the global wild fish stock irreversibly has been reached for several fish species [11]. At the same time there is an increasing demand for omega-3 PUFA on the global market. Therefore, new sources of omega-3 PUFA are needed. By-products from processing of wild caught fish and fish from aquaculture could be a valuable source of omega-3 PUFA for human consumption [12]. As a presence of high degree of unsaturation, fish oil possess high tendency to oxidation especially when exposed to heat during extraction and storage. The conventional fish processing methods for oil extraction, fractionation and purification include hydraulic pressing, vacuum distillation, hexane extraction, and conventional crystallization, which all involve high temperature processing or flammable or toxic solvents [13]. These methods can contribute to the loss, denaturation, or decomposition of the precious nutrition of fish oil. Traditional pressing is a good approach for preserving oil quality and used by many fish waste processing industry for the extraction of oil but the oil yield is low. In this regard, supercritical fluid extraction is a promising method for the extraction and fractionation of edible oils containing labile PUFA, which can be carried out under mild operating conditions [14]. Besides, extraction with supercritical carbon dioxide (SC-CO2) offers new opportunities for the solution of separation problems as it is nontoxic, nonflammable, inexpensive and clean solvent. The solvating capacity of SC-CO2 fluid can be controlled by manipulating pressure and/or temperature to give suitable selectivity. So, the temperature and pressure applied greatly affected the oil solvating power of SC-CO2, and hence, the yield [15]. The temperature and pressure applied in this present study for SC-CO2 extraction were selected from previous report [16] with slight modifications and extraction time was fixed by repeated trail until oil extraction finished. Commercially, Atlantic salmon fishery is very important around the world; however, there is no research work
reported regarding comparative analysis of pressed, SCCO2 and organic solvent extracted oils from belly part, trimmed muscle, frame bone and skin. The aim of this work was to evaluate the oil yield, physical properties (color and viscosity), oil stability (acid value, peroxide value, free fatty acid value, p-anisidine value, total oxidation value, oxidative stability index), lipid classes and antioxidant properties (DPPH, ABTS?, FRAP and OHscavenging activity) of oils extracted by SC-CO2 and organic solvent (n-hexane) from different by-products for value addition.
Materials and Methods Chemicals and Reagents Carbon dioxide (CO2) gas purity was 99.99 % and it was supplied by KOSEM (Yangsan, Korea). p-Anisidine, DPPH, ABTS?, trolox, ascorbic acid, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and all other chemicals and reagents were purchased from SigmaAldrich, St. Luis, Mo., USA. All reagents and solvents used in this study were of analytical or high performance liquid chromatography (HPLC) grade. Sample Collection and Preparation Atlantic salmon by-products such as belly part, trimmed muscle, frame bone and skin were collected from Wooyoung Fisheries Co., Ltd. (fish imported from Norway), Saha-gu, Busan, Republic of Korea. Pressed salmon belly part oil was also collected from the same company for comparative analysis. The samples were washed thoroughly with cold distilled water (4 °C) and freeze dried for 72 h using EYELA FDV-2100, Rikakikai Co. Ltd., Tokyo, Japan. After drying, samples were crushed by an electric blender (Hanil, HMF-3260S, 2000 mL) and then were stored at -20 °C for oil extraction. Hexane Extraction Extraction with n-hexane was performed by placing 40 g of freeze dried raw crushed sample into a beaker with 200 mL n-hexane and stirred at 300 rpm for 20 h at 45 °C. The mouth of beaker was tightly closed by aluminum foil paper for protecting the evaporation of solvent. After extraction, the hexane solution was filtered using 125 mm F1113 grade filter paper (Chmlab group, Barcelona, Spain) and then was evaporated in a rotary vacuum evaporator at 40 °C. The extracted oil was stored at -20 °C until analysis. Oil extracted by n-hexane was considered as total oil and calculated from Eq. 1
123
Waste Biomass Valor
Total oil ð%Þ ¼
Wt: of obtained oil 100 Wt: of sample ðdry basisÞ
Yield ð%Þ of total oil Wt: of obtained oil 100 ¼ Wt: of oil extracted by n hexaneðdry basisÞ
ð1Þ
ð2Þ
Supercritical Carbon Dioxide (SC-CO2) Extraction A laboratory scale SC-CO2 extraction process (Fig. 1) had been used for oil extraction from different by-products of salmon. Exactly, 100 g of freeze dried crushed sample was filled into the stainless steel extraction vessel of 200 mL. To avoid entering of sample through gas line, a thin layer of cotton was placed at the bottom of the extraction vessel and top of the sample. After that, the extraction vessel was plugged with a cap. A high pressure pump (Milroyal, Milton Roy, USA) was applied to pump liquid CO2 into the extraction vessel for reaching the desired pressure. The CO2 pressure was controlled by a back pressure regulator (BPR). For maintaining the temperature, water baths were connected to the extraction vessel and separator. A gas flow meter (Shinagawa, DC-1, Tokyo, Japan) was used to measure the consumed CO2 during the extraction period. The oil from the samples was extracted at 45 °C and pressure 25 MPa. CO2 flow rate was constant at 27 g/min during the whole extraction period of 3 h. Finally, extracted oil was collected from the separating vessel and stored at -20 °C until further use and analysis. Yield (%) of total oil by SC-CO2 was obtained from Eq. 2 1 : CO2 tank 2 : Pressure gauge 3 : High pressure pump 4 : Cooling bath 5 : Heat exchanger 6 : High pressure vessel 7 : Separator 8 : Collect vessel 9 : Flow meter 10 : Digital thermometer 11 : On-off valve 12 : Check valve 13 : Safety valve 14 : BPR 15 : Needle valve 16 : Filter
1
1
Viscosity Rheological study of the oil was done using a viscometer (model DVII—Brookfield, Middleboro, USA), with a small sample adapter, spindle 62, which permits the use of only 20 mL of oil in each analysis. Temperature was controlled using a water bath at 22 °C with precision of ±2 °C.
2 9
7
6 5
15 13 5 12
4
3 14
Fig. 1 Schematic diagram of the SC-CO2 extraction process
123
Color measurement of the oil samples was carried out using a Lovibond RT Series, Portable Reflectance spectrophotometers, Solstice Park, Amesbury, UK. The instrument was standardized each time with a black and a white. The results were expressed through L*, a* and b* where L* value is the ‘‘lightness’’ of a sample from 0 to 100 with 100 being pure white, the a* value describes red (?) to green (-) and the b* value represents yellow (?) to blue (-).
T
16 11
Color Measurement
10
2
2
Physical Properties of Oil
8
Waste Biomass Valor
Oil Stability Tests Acid Value (AV) The acid value was determined as mg KOH/g according to AOCS official method [17]. Peroxide Value (POV) The peroxide value was determined as meq/kg according to AOCS official method [18]. Free Fatty Acid Value (FFA Value) The free fatty acid value (%) was determined according to AOCS official method [19].
p-Anisidine value was determined by AOCS official method [20]. First of all, oil samples were filtered through a Whatman No. 40 filter paper to remove moisture and impurities. 1.0 g of oil sample was accurately weighed in a 50 mL volumetric flask. The oil samples were dissolved and diluted with 25 mL 2, 2, 4-Trimethylpentane (iso-octane). The absorbance of the oil sample was measured at 350 nm using a spectrophotometer (UVmini-1240 UV–Vis Spectrophotometer, USA). 5 mL sample of oil was pipetted into one test tube and 1 mL of p-anisidine reagent was added. A 5 mL of iso-octane was added to another test tube and 1 mL of p-anisidine reagent was added to it and used as a blank. The p-anisidine reagent was prepared by adding 0.25 g p-anisidine to 100 mL of glacial acetic acid. After 10 min, the absorbance of the oil sample with the p-anisidine reagent was measured at 350 nm. The p-anisidine value was determined following the Eq. 3 25 ð1:2As AbÞ W
Radical Scavenging Activity 2,2-Diphenyl-1-picrylhydrazyl (DPPH) Radical Scavenging Activity
p-Anisidine Value (PAV)
p Anisidine value ¼
a stream of air was bubbled into oil sample (5 g) contained in a reaction vessel placed in an electric heating block. Effluent air containing volatile organic acids from the oil samples were collected in a measuring vessel containing distilled water (40 mL). The conductivity of the water was measured automatically as oxidation proceeded. Filtered, cleaned, dried air was allowed to bubble through the hot oil at rates of 20 L/h. The OSIs of the oil samples were automatically recorded maintaining temperature at 121.6 °C. For each time studied, eight samples were accommodated in the equipment and analyzed simultaneously. Samples for all determinations were randomized on their position in the heating block.
ð3Þ
where As = Absorbance of the oil solution after reaction with the p-anisidine reagent; Ab = Absorbance of the oil solution; W = Weight of oil (g).
DPPH free radical scavenging activity of salmon by-product oils was measured according to Blois [22] with slight modifications. Briefly, 0.2 mM solution of DPPH was prepared in ethanol and 3.9 mL of this solution was added to 100 lL of salmon by-product oil. This solution was vortexed thoroughly for 4 s and incubated at room temperature in dark. After 30 min., the absorbance of the DPPH mixed oil sample was measured at 517 nm against blank. Lower absorbance of the reaction mixture indicated higher DPPH free radical scavenging activity. A sample blank and control samples (trolox, BHA and BHT at 300 lg/mL in ethanol and ascorbic acid at 300 lg/mL in distilled water) were also measured using the same method and Eq. 4 DPPH radical scavenging activity ð%Þ As Ao ¼ 1 100 Ac
ð4Þ
where As is the absorbance in the presence of salmon byproduct oil at 517 nm, Ac is the absorbance of the control which contains 3.9 mL control reaction (containing DPPH solution except the salmon by-product oil) at 517 nm, and Ao is the absorbance in the presence of salmon by-product oil and ethanol at 517 nm.
Total Oxidation (TOTOX Value) TOTOX (Total Oxidation) value was calculated as twice the peroxide value plus p-anisidine value. Measurement of Oxidative Stability Index (OSI) Oxidative stability index (OSI) of salmon by-product oils was measured using a Metrohm Rancimat, model 743 (Herisau, Switzerland) according to Farhoosh [21]. Briefly,
2,20 -Azino-di(3-ethylbenzthiazoline-6-sulfonate) (ABTS?) Radical Scavenging Activity For the 2,20 -azino-di (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) assay, we followed the method of ZhelevaDimitrova et al. [23] with slight modifications. ABTS was dissolved in water to make a concentration of 7 mM/L. ABTS? was produced by mixing equal volume of ABTS stock solution with 2.45 mM/L potassium persulfate and
123
Waste Biomass Valor
allowing the mixture to stand in the dark at room temperature for 16 h. To test the samples, the ABTS? stock solution was diluted with 94 % ethanol to an absorbance of 0.70 ± 0.02 at 734 nm. 3.9 mL of diluted ABTS? was added with 100 lL of oil sample and the mixture was kept in a dark environment at room temperature for 6 min. The absorbance of all the sample solutions was measured at 734 nm. A sample blank and control samples (trolox, BHA and BHT at 300 lg/mL in ethanol and ascorbic acid at 300 lg/mL in distilled water) were also determined according to the Eq. 5 þ ABTS radical scavenging activity ð%Þ As Ao 100 ¼ 1 Ac
ð5Þ
where As is the absorbance in the presence of salmon byproduct oil at 734 nm, Ac is the absorbance of the control which contains 3.9 mL control reaction (containing ABTS1 solution except the salmon by-product oil) at 734 nm, and Ao is the absorbance in the presence of salmon by-product oil and ethanol at 734 nm. Ferric ions (Fe3?) Reducing Antioxidant Power Assay (FRAP) The ferric ions (Fe3?) reducing antioxidant power (FRAP) assay was done according to Oyaizu [24] with slight modifications. 100 lL of salmon by-product oil sample was mixed with 2.5 mL sodium phosphate buffer (0.2 M, pH 6.6) and 2.5 mL of potassium ferricyanide [K3Fe(CN)6] (1 %) solution. The mixture was incubated at 50 °C for 20 min. Aliquots (2.5 mL) of trichloroacetic acid (10 %) were added to the mixture. Then, 2.5 mL of this solution was mixed with 2.5 mL distilled water and 0.5 mL FeCl3 (0.1 %), and the absorbance was measured at 700 nm. A sample blank and control samples (trolox, BHA and BHT at 300 lg/mL in ethanol and ascorbic acid at 300 lg/mL in distilled water) were also measured according to Eq. 6 Abs sample Abs blank 100 FRAP activity ð%Þ ¼ Abs blank
ð6Þ
where Abssample is the absorbance in the presence of salmon by-product oil at 700 nm, Absblank is the absorbance of the control which contains all the reagents without oil sample.
sulfate (0.7 mM/L), and 1 mL of H2O2 (0.01 %) were mixed and incubated at room temperature for 30 min. Then the absorbance of the mixture sample was measured at 510 nm. A sample blank and control samples (trolox, BHA and BHT at 300 lg/mL in ethanol and ascorbic acid at 300 lg/mL in distilled water) were also measured by same method and the values were calculated by Eq. 7 The hydroxyl radical scavenging activity ð%Þ A A1 ¼ 100 A2 A1
ð7Þ
where A, A1, and A2 are the absorbance value of the system with all solutions, including H2O2 and the sample solution, the system without the sample solution, and the system without both H2O2 and the sample solution, respectively. Fatty Acid Composition Analysis Gas chromatography (GC) analysis was performed to determine the fatty acid composition of salmon by-product oils. The GC analysis was performed using a 6890 Agilent (Agilent Technologies, Wilmington, USA) gas chromatograph with a fused silica capillary column (100 m length 9 0.25 mm internal diameter, 0.2 lm of film) (Supelco, Bellefonte, USA). Fatty acid methyl esters were prepared according to official methods and recommended practices of the American Oil Chemists’ Society [26]. Oven temperature was programmed to start with a constant temperature of 130 °C for 3 min, then increased to 240 °C at a rate of 4 °C/min and then held at 240 °C for 10 min. The temperature of both injector and detector was 250 °C. Fatty acid methyl esters were identified by comparing the retention time with a standard fatty acid methyl ester mixture (Supelco, Bellefonte, PA., USA). Statistical Analysis Values are presented as the mean ± standard deviation of triplicate determinations. Statistical analysis was carried out by one-way analysis of variance (ANOVA) using SPSS software (version 18.0 software, SPSS Inc., Chicago, IL, USA). Significant differences between means were determined by Duncan’s Multiple Range tests and P \ 0.05 was regarded as significant.
Hydroxyl Radical Scavenging Activity
Results and Discussion Hydroxyl radical scavenging activity was determined according to the method of Beara et al. [25] with some modifications. A 100 lL of salmon by-product oil sample, 1 mL of ortho-phenanthroline (7.5 mM/L), 1.5 mL of sodium phosphate buffer (0.15 M, pH 7.4), 1 mL of ferrous
123
Yield of Oil Oil obtained (% dry matter basis) from the salmon belly part, trimmed muscle, frame bone and skin was influenced
40
c
b
b d
cd
e
61.07c ± 0.70 60.42c ± 0.78 60.60c ± 1.08 59.26c ± 1.51 63.80b ± 0.95 cP
Viscosity
Values are mean ± SD of three determinations. Means with the different superscript letter in each row differ significantly (P \ 0.05)
64.41b ± 1.22 67.70a ± 1.61
?16.49 ?21.92 ± 0.38 ?21.38 ± 0.55 ?13.53 ± 0.45 ?20.28 ± 0.54 ?15.31 ± 0.41
b*
?16.42 ± 0.42
e d
a*
64.55b ± 1.37
?16.49 ± 0.47 ± 0.35
d
?10.58 ± 0.34 ?11.68 ± 0.45
g a
?10.56 ± 0.36 ?9.68 ± 0.38
a f
?11.64 ± 0.17 ?15.62 ± 0.31 ?14.67 ± 0.30
?14.21 ± 0.42
b
d c
20.41b ± 0.55 15.96d ± 0.50
d e
22.90ab ± 0.35 22.48ab ± 0.49 23.89a ± 0.38 22.10b ± 0.20
Belly part Belly part
c
24.07a ± 0.21
Skin Frame bone SC-CO2 extracted oils
Salmon by-product oils are characteristically crimson red color due to high content of astaxanthin (3,30 -dihydroxy,carotene-4,40 -dione), a reddish pink-colored carotenoid [28]. For normal fish oils and other edible oils, consumers prefer bright light colored oil but in case of salmon byproduct oils, the color is due to carotenoid pigments which have several health beneficial issues [29]. Researchers encouraged taking 2-4 mg astaxanthin/day for an adult person [30]. The most frequently used instrumental color measures are the L*, a*, b* systems, which primary parameters are lightness (L*), redness (a*) and yellowness (b*). The a* value generally exhibits the best correlation to increasing carotenoid levels [31]. The a* value of pressed belly part oils and SC-CO2 extracted belly part, trimmed muscle and bone oil was higher than hexane extracted oils due to high content of astaxanthin pigments (Table 1). In this study, hexane extracted salmon by-product oils
Pressed oil
Color of Salmon By-products Oil
Table 1 Color and viscosity of pressed, SC-CO2 extracted and n-hexane extracted salmon by-product oils
by different procedures of extraction Fig. 2. In this study, maximum oil was obtained by n-hexane extracted salmon belly part oil (49.26 %) followed by salmon skin, trimmed muscle and frame bone (45.46, 45.45 and 44.44 % respectively). SC-CO2 showed medium quantity of yield and calculated as 76.21, 86.99, 82.15 and 84.31 % of total oil from belly part, trimmed muscle, frame bone and skin respectively (oil obtained by n-hexane extraction is considered as total oil). Traditional pressing showed the lowest percentage yield of 61.83 % of total oil (secondary data from the company). SC-CO2 is highly selective and extracts non-polar compounds whereas n-hexane with high efficiency of solubility with poor selectivity to extract amphiphilic and non-polar compounds, e.g. phospholipids which provided the maximal value of extracted oil in case of n-hexane. Mackerel oil obtained from SC-CO2 extraction at 45 °C and 25 MPa was 78.06 ± 1.55 % of total oil [27].
n-Hexane extracted oils
Fig. 2 The percentage of oil yield from salmon by-products by different methods. Values are of Mean ± SD (n = 3). Different small letters in each column bar indicate significant differences (P \ 0.05)
a
Skin
L*
Bone
Color
Trimmed muscle
Trimmed muscle
Belly part
Trimmed muscle
0
Belly part
10
b
Frame bone
20
b
15.22d ± 0.23
30
The L* value is the ‘‘lightness’’ of a sample from 0 to 100 with 100 being pure white; a* value describes red (?) to green (-); b* value represents yellow (?) to blue (-); c P = centipoise, 1 centipoise = 0.01 g per centimeter-second
b d
64.88b ± 1.35
Hexane extracted
Skin
50
Oil yield (%)
SC-CO2 extracted
?18.03c ± 0.29
Pressed a
?10.39d ± 0.29
60
17.73c ± 0.84
Waste Biomass Valor
123
Waste Biomass Valor
showed lower L* values (15.96–20.41) than pressed (22.10) and SC-CO2 extracted oils (22.48–24.07) which indicates the presence of dark compounds due to oxidative products and processing conditions. The color is contributed by pigment content, impurities, oxidation compound and the processing process [32]. The lower the b* values determining the characteristics bright and yellowness of oils preferred by the consumers. In this regard, b* value of pressed belly part oil and SC-CO2 extracted belly part and frame bone were lower (b* = 16.24, 15.31 and 13.53 respectively) due to high quality of extracted oils with high purity. Oils obtained from red and pink salmon head showed L*, a* and b* values of 32.1 and 40.3, 4.9 and 2.7, 14.6 and 16.6 respectively [32]. Crude oil refining is an important step for edible oil preparation where oil color, brightness/lightness play an important role for the cost. The color of oils is a determining factor in quality because darkcolored oils require high-cost processing to achieve an acceptable light-colored product [33]. Viscosity of Oil The viscosity of SC-CO2 extracted salmon by-product oils were showed significantly lower values (centipoise, cP) (P \ 0.05) compared to pressed and n-hexane extracted oils (Table 1). Among all the oil samples, the lowest value of viscosity was found in SC-CO2 extracted belly part oil (cP = 59.26) and highest value was found in hexane extracted belly part oil (cP = 67.70) due to the extent of different classes of lipids. Hexane has high efficiency of extractability with poor selectivity and extracts all classes of non-polar and amphiphilic lipids (mostly unsaponifiable gumming compounds, e.g. phospholipids) which are responsible to increase viscosity of oil. The acceptable range of viscosity of edible fish oil is Cp = 60–90 at 20 °C [34]. The lower value of SC-CO2 extracted oils was the indication of high quality and purity. The increase of viscosity in fish oil is due to impurity as reported by Suseno et al. [35]. Therefore, viscosity is related to the chemical properties of the oils such as chain length and saturation/ unsaturation [36]. High viscous oil needs more cost for refining and adsorbent treatment could cause viscosity to decrease [37]. Oil Stability Tests Acid Value (AV) Acid value is an indicator of acidity of fish oil due to the presence of free fatty acids and other non-lipid acidic compounds. Free fatty acids are mainly generated by hydrolysis reaction of triacylglycerides, whereas non-lipid acid compounds, such as acetic acid, may be generated
123
during spoilage of the raw material [38]. Hydrolysis of triacylglycerol is affected by contact of atmospheric oxygen, hot moist air or microbial attack in raw materials. Acid value obtained from the pressed, SC-CO2 extracted and hexane extracted oils from salmon by-products are presented in Table 2. Pressed salmon belly part oil showed the lowest acid value (6.29), then the SC-CO2 extracted oils showed values within the acceptable limit (7–8 mg/ KOH g) [39] but hexane extracted oils showed the acid values beyond the acceptable limit ([10). The authors also conducted research on enzymatic extraction of oil from salmon head, frame bone and gut and found the acid value of oil in wide range of 0.33–17.49 mg/KOH g. High AV of hexane extracted by-product oils might be due to unexpected oxidation and changes in oil for long time heat application and exposure to air. Oil obtained by SC-CO2 presents lower acidity than the oils obtained by non-SFE procedures, which may indicate that, in this case, the hydrolysis of triacylglycerides, and therefore the release of FFA [38]. The acid value of the oil depends upon several factors including: oil composition, extraction procedure, sample preparation and freshness of raw material [40]. Boran et al. [41] reported that an increase in acid value was due to the lipase activity present in the microorganisms or fish tissue. Peroxide Value (POV) and p-Anisidine Value (PAV) The POV test is a conventional method for quantifying total hydroperoxides produced by primary oxidation due to thermo-oxidative or lipid oxidation process [42]. The oxidation products later break down to produce lower molecular compounds, such as free fatty acids, alcohols and aldehydes [41]. The PAV is used to determine the amount of secondary oxidation of oil and the measurement of aldehydes with a- and b-unsaturation. Obtained POV in the present study from different by-product oils extracted by different methods were between 0.97 and 1.68 meq/kg (Table 2) which were within recommended limit (B5 meq/ kg) [43]. Pressed belly part oil showed the lowest (0.97), then SC-CO2 extracted oils showed medium (1.10–1.25) and hexane extracted oils showed the highest (1.36–1.68) POV. The allowable limit of PAV set by Global Organization for EPA and DHA (GOED) and FAO of the United Nations for quality and acceptability of fish oils for human consumption is B20 [44]. The lowest value was found in SC-CO2 extracted oil (3.21–5.48), moderate value was found in pressed belly part oil (6.13) and the highest value was found in n-hexane extracted oils (9.15–10.23) (Table 2). Sahena et al. [45] found higher content of POV in the Soxhlet extracted oils than SC-CO2 extracted oils of tuna head, skin and viscera. Aidos et al. [46] reported panisidine value of 8.9 ± 0.5 from herring oil obtained from
1.36d ± 0.02 0.49 ± 0.06 1.08 ± 0.06 Values are mean ± SD of three determinations. Means with the different superscript letter in each row differ significantly (P \ 0.05)
± 0.04 1.45 1.62 ± 0.04 1.37 ± 0.13 2.14 ± 0.03 1.93 ± 0.30
1.63 ± 0.10 OSI value (h)
13.10a ± 0.50 12.81 ± 0.45
f e
12.51 ± 0.61 12.95 ± 0.90
cd c
7.57 ± 0.49 7.86 ± 0.64
d a
7.43 ± 0.47 5.41 ± 0.28
b c
8.07 ± 0.43 TOTOX value
9.92ab ± 0.74 9.81ab ± 1.01
a a
9.15b ± 0.51 10.23a ± 0.47 ± 0.29
a b
cd
5.37 ± 0.18 cd
5.48
b b
4.93d ± 0.31
c
3.21e ± 0.28 6.13c ± 0.24 p-Anisidine value
b
4.74a ± 0.18 ± 0.31 4.18 ± 0.21 4.46 ± 0.22 4.08 3.89 ± 0.40 3.42 ± 0.28 3.32 ± 0.16 3.23 ± 0.31
2.37 ± 0.19 Free fatty acid value (%)
1.59ab ± 0.18 ± 0.15 1.50
bc ab
1.68 ± 0.20 ± 0.28 1.36
bc c
± 0.24 1.10 ± 0.08 1.19
d d
± 0.14 1.25 ± 0.20 1.10
d e
0.97 ± 0.12 Peroxide value (meq/kg)
10.28b ± 1.25 10.28b ± 0.61
abc a
11.03a ± 0.52
abcd
10.47ab ± 0.41 8.03c ± 0.35
de cde
7.85c ± 0.56 ± 0.62 cd
7.48
bcde de
7.85c ± 0.46 6.92d ± 0.32 Acid value (mg KOH/g)
e
Trimmed muscle Belly part Skin Frame bone Trimmed muscle Belly part Belly part
SC-CO2 extracted oils Pressed oil Parameters
Table 2 Stability properties of pressed, SC-CO2 extracted and n-hexane extracted salmon by-product oils
n-Hexane extracted oils
Frame bone
Skin
Waste Biomass Valor
by-products. Boran et al. [41] studied the changes in the quality of garfish, golden mullet, shad and mackerel oils due to storage temperature and time and the p-anisidine value ranged from 1.74 to 14.09. Salmon by-products had high content of polyunsaturated fatty acids, which made the oil highly susceptible to oxidative spoilage [47]. High POV and PAV values in n-hexane extracted oils might be a result of the effects of long term processing and exposure to air. There are several factors including: lipid class composition, concentration of oxygen, light and presence of antioxidants that influence the formation of hydroperoxides and degradation into secondary oxidation products [48, 49]. Fish oil is highly susceptible to oxidative damage and the rate of oxidation increases with increasing unsaturated fatty acid content in oil. Therefore, mild extraction methods are preferred to minimize oxidative deterioration as well as formation of undesirable co-products [8]. Free Fatty Acid Value (FFA Value) FFA value determines the free fatty acid content of oils generated by hydrolysis of ester bonds of triacylglycerol. Pressed belly part oils showed the lowest FFA value (2.37 %) whereas SC-CO2 extracted oils showed medium values (3.23–3.82 %) and hexane extracted oils showed the highest values (4.08–4.74 %) (Table 2). All the oils showed FFA values with in the allowable limit. According to Bimbo [34] the allowable limit of free fatty acids for crude fish oil is in the range of 1–7 % but usually 2–5 %. Sahena et al. [45] reported higher FFA value in Soxhlet extracted tuna head, skin and viscera oil than SC-CO2 extracted oils. Oils extracted at higher temperature for long time render higher FFA value [50]. Involvement of heat and exposure to air for long time in n-hexane extracted oils might cause higher FFA value. In the respect of FFA value, the quality of pressed and SC-CO2 extracted salmon byproduct oils showed superior quality than solvent extracted oil. Total Oxidation Value (TOTOX Value) TOTOX value of pressed belly part oil, SC-CO2 and nhexane extracted belly part, trimmed muscle, bone and skin oils are provided in Table 2. TOTOX value of SCCO2 extracted salmon by-product oils showed premium quality (5.41–7.86) over pressed belly part oil (8.07) and nhexane extracted oils (12.51–13.10). The allowable limit of TOTOX value for quality and acceptability of fish oils for human consumption is B26 [44]. SC-CO2 extraction, which was carried out under lower oxidizing conditions (mild temperatures, non-oxidant atmosphere and darkness) than other procedures, made possible to reduce significantly the TOTOX value [38]. Oil extracted from herring
123
Waste Biomass Valor
by-products showed TOTOX value of 14.9 [46] which was supportive of present research value. Boran et al. [41] reported the TOTOX value of garfish, golden mullet, shad and mackerel ranged from 8.04 to 35.29.
oil from SC-CO2 extraction compared to oils extracted by organic solvent (hexane) was also reported by Jung et al. [51]. It indicated that SC-CO2 extracted oil had more efficiency to delay the oxidation in unfavorable environments.
Oxidative Stability Index (OSI) Radical Scavenging Activity The Rancimat induction time (h) of pressed belly part oil, SC-CO2 extracted and hexane extracted belly part, trimmed muscle, frame bone and skin oil is given in Table 2. The induction period of SC-CO2 extracted trimmed muscle and belly part oils was higher (2.14 and 1.93 h, respectively) than that of pressed and hexane extracted oils. The factors that determine the induction time is status of oil regarding the extent of oxidation and antioxidative properties such as presence of carotenoid pigments (astaxanthin), tocopherol, phospholipids etc. SC-CO2 extracted belly part and trimmed muscle oils might contain these compounds in higher quantity than other oils. SC-CO2 extraction was done under closed condition and shorter extraction period rendering lower extent of oxidation and higher induction time. In nhexane extracted oils, antioxidative properties might be damaged due to prolonged extraction period, temperature and contact of air for long time. Higher induction period of
Oils from salmon by-products were found to differ significantly (P \ 0.05) in terms of their DPPH scavenging ability (Fig. 3a). The maximum scavenging activity was found 83.2 ± 2.24, 78.20 ± 1.78 and 70.40 ± 2.13 % in SC-CO2 extracted skin, trimmed muscle and belly part oils, respectively. Pressed belly part oils showed the lowest scavenging ability of 54.70 ± 1.56 % and then hexane extracted belly part oil (55.5 ± 1.41 %). Among the antioxidants, ascorbic acid showed the highest value of 92.64 ± 2.0 % and BHT showed the lowest value of 35.61 ± 1.71 %. Jung et al. [51] reported higher DPPH activity of SC-CO2 (Temp: 50 °C and pressure 25 MPa) extracted oil than organic solvent extracted oil.
(b) 120 100 80 60 40 20 0
f
d
ef
c g
g
f
g
e
b
a h
i
ABTS activity (%)
DPPH activity (%)
(a)
2,2-Diphenyl-1-picrylhydrazyl (DPPH) Radical Scavenging Activity
100 80 60 40 20 0
c
b
c
c
a
(d) a e h
d
ef hi
f
g
fg
d
bc
b
i
Oils and antioxidants Fig. 3 Radical scavenging activity of salmon by-product oils. a 2,2Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity. b 2,20 -Azino-di (3-thylbenzthiazoline-6-sulfonate) (ABTS?) radical scavenging activity. c Ferric ions (Fe3?) reducing antioxidant power assay (FRAP) and d hydroxyl ions radical scavenging activity. Values are the result of Mean ± SD (n = 3). Different letters on each column bar indicate significant differences (P \ 0.05). (PBePO
OH- activity (%)
FRAP activity (%)
a
d
d
d
d
Oils and antioxidants
(c)
123
bc
e
Oils and antioxidants
100 80 60 40 20 0
c
100 80
de
cd def ef
cd
ab g
g
h
f
a
b
c
60 40 20 0
Oils and antioxidants Pressed belly part oil, SCBePO SC-CO2 extracted belly part oil, SCTMO SC-CO2 extracted trimmed muscle oil, SCBO SC-CO2 extracted bone oil, SCSO SC-CO2 extracted skin oil, HBePO nhexane extracted belly part oil, HTMO n-hexane extracted trimmed muscle oil, HBO n-hexane extracted bone oil, HSO n-hexane extracted skin oil, BHA butylated hydroxyanisole and BHT butylated hydroxytoluene)
Waste Biomass Valor
2,20 -Azino-di(3-ethylbenzthiazoline-6-sulfonate) (ABTS?) Radical Scavenging Activity Oils extracted from salmon by-products showed difference regarding ABTS? radical scavenging activity (Fig. 3b). The maximum scavenging activity was found 85.18 ± 0.95 % in SC-CO2 extracted belly part oils followed by 82.78 ± 2.32 and 82.21 ± 1.08 % in SC-CO2 extracted skin and trimmed muscle oils, respectively. Pressed belly oil showed 80.22 ± 1.19 % scavenging activity and the lowest scavenging activity was found in organic solvent extracted belly part oil (69.54 ± 0.85 %). Among the antioxidants, trolox showed the highest value of 90.65 ± 2.27 % followed by BHA, ascorbic acid and BHT 89.95 ± 1.67, 82.18 ± 1.73 and 53.09 ± 1.62 %, respectively. Ferric ions (Fe3?) Reducing Antioxidant Power Assay (FRAP) The result of FRAP assay of salmon by-products oils is given in Fig. 3c which showed variable FRAP activity of different oils. The maximum FRAP activity was showed by SC-CO2 extracted skin oil (64.48 ± 2.0 %) followed by SC-CO2 extracted belly part and trimmed muscles (58.60 ± 0.97 and 56.0 ± 1.53 %, respectively). Pressed belly part oil showed 42.18 ± 1.71 % scavenging activity and the lowest scavenging activity was found in n-hexane extracted bone oil (39.42 ± 1.18 %). FRAP reducing power of standard antioxidants exhibited the following order- ascorbic acid [ BHT [ BHA [ trolox. Hydroxyl Radical Scavenging Activity The hydroxyl radical scavenging activity of the various salmon by-products oils and standard antioxidants was investigated (Fig. 3d). The highest hydroxyl radical scavenger activity was observed at SC-CO2 extracted skin oil (72.15 ± 2.19 %) followed by SC-CO2 extracted belly part (71.31 ± 1.56 %) and then pressed belly part oil (70.47 ± 1.1 %). The lowest hydroxyl radical scavenger was n-hexane extracted bone oil (57.56 ± 2.52 %). Among the standard antioxidants, ascorbic acid showed the strongest hydroxyl radical scavenging activity (82.58 ± 2.19 %) followed by trolox, BHA and BHT (80.14 ± 1.64, 78.82 ± 2.21, 74.12 ± 2.18 %, respectively). The compounds in salmon by-product oils showing radical scavenging activity include tocopherols, carotenoids (specially, astaxanthin), phospholipids, and phenolic compounds. The major function of tocopherol is namely as an antioxidant and a-tocopherol scavenges the peroxyl radical about 10 times faster than the lipid reacts with the radical [52]. a-Tocopherol content in cultured salmon was found 3.58 mg/100 g muscle tissue soluble in
oil [53]. The significant crimson red color of salmon and trout is due to astaxanthin [54]. Antioxidant synergism of carotenoids and astaxanthin is reported [55]. The astaxanthin concentration of wild Atlantic salmon (Salmo salar) was reported [56] to lie between 3.1 and 8.1 mg/kg. Carotenoids are able to quench free radical species such as singlet oxygen. Carotenoids are suggested to react with peroxyl radicals to form a resonance stabilized radical [57] and perhaps by electron transfer to form the alkyl peroxide anion and carotenoid radical cation [58]. In solution, astaxanthin exits in an equilibrium, the extent of which depends on the solvent, with the enol form of the ketone, thus the resulting ortho-dihydroxy-conjugated polyene system possess a hydrogen atom capable of acting as a chain breaking in free radical reaction [59]. Miki [60] found approximately 10 times stronger scavenger activities of oxygen species by astaxanthin than by zeaxanthin, lutein, tunaxanthin, canthaxanthin and b-carotene and 100 times greater than those of a-tocopherol. Synergistic interaction between carotenoids and tocopherols in preventing oxidation in foods has been reviewed [54]. Saito and Ishihara [61] reported the antioxidant activity and active sites of phospholipids as antioxidants. According to Pokorny´ [62], phospholipids catalyze the destruction of hydroperoxides probably by forming labile complexes with dimeric hydroperoxides, which are decomposed without formation of free radicals. The antioxidant activity of the pink salmon oils was reported 0.89 ± 0.15 lmol Trolox equivalent/g of crude oil [63]. They also noted that, the raw material was heated during the oil extraction procedure, which could reduce the antioxidant activity. This report agreed with the higher antioxidant activity of SC-CO2 extracted salmon by-product oils of the current study. Fatty Acid Composition Analysis Fatty acids composition (area %) of salmon by-product oils obtained by different methods are given in Table 3. The table showed that only 16 of 37 types of authentic standard fatty acids were identified in salmon by-products oil. The fatty acids constituents in the oil extracted from different by-products using different methods was found to show difference but there is no homogeneity showing among the values of samples or extraction methods. In salmon by-product oils, oleic acid (C18:1n9c) showed the maximum quantity of 33.39 ± 0.40–36.90 ± 0.90 % followed by linoleic acid (C18:3n6), palmitic acid (C16:0) and linolenic acid (C18:3n3) in the quantity of 19.00 ± 1.45–22.43 ± 0.40 %, 12.50 ± 0.12–13.7 ± 0.10 and 5.19 ± 0.16–6.50 ± 0.25 % respectively. SC-CO2 extracted belly part oils showed the highest (4.54 ± 0.12 %) whereas hexane extracted belly part oils showed the lowest (3.12 ± 0.09 %) percentage of EPA (C20:5n3) content. In
123
123 c
± 0.15
6.4ef ± 0.60 54.47de ± 0.80
11.00a ± 0.50
54.24e ± 1.0 b
± 0.59
39.13 ± 0.25
a
23.77 ± 0.49
a
13.35 ± 0.32
c
± 0.12
bc
± 0.09
± 0.30
± 0.81
39.0 ± 0.38
a
b
21.03 ± 0.69
12.62
ab
57.99ab ± 1.30
6.48ef ± 0.20
3.46de ± 0.21
3.53d ± 0.07
0.80b ± 0.06
ND
1.88
5.63
bc
1.68de ± 0.09
ND
20.23 ± 0.20
b
3.47bc ± 0.21
3.88 ± 0.13 36.17ab ± 0.46
d
3.27bc ± 0.09
13.40
ab
2.60 ± 0.20
ND
± 0.20
± 0.30
cd
± 0.17
± 1.2 35.21
cd
± 0.92
20.18 ± 0.94
b
13.23
ab
56.28bcd ± 0.89
8.96b ± 0.86
3.60
4.27b ± 0.11
0.76b ± 0.06
ND
1.80 ± 0.10
c
5.35 ± 0.25
c
1.55e ± 0.10
0.92
ab
19.42
bcd
3.40bcd ± 0.26
3.64 ± 0.11 34.24de ± 0.22
e
3.38b ± 0.15
13.7 ± 0.10
a
2.90 ± 0.10
b
1.05b ± 0.16
Frame bone
± 0.24
± 0.14
± 0.72
36.11
bc
± 1.02
20.68 ± 0.81
b
13.40 ± 0.4
a
55.58cde ± 1.0
8.31bc ± 0.94
3.26ef ± 0.10
3.87c ± 0.16
0.92ab ± 0.08
ND
2.03
ab
6.27
ab
1.97abc ± 0.09
ND
19.76
bc
3.29de ± 0.18
4.21 ± 0.10 34.75 cd ± 0.50
bc
3.07c ± 0.07
12.50 ± 0.12
d
2.18 ± 0.10
d
1.92a ± 0.24
Skin
b
± 0.50
a
± 0.57
± 0.29 37.30 ± 0.49
b
22.79 ± 0.46
a
12.10
ab
55.62cde ± 1.20
7.29de ± 0.29
3.23ef ± 0.12
3.12e ± 0.09
0.88ab ± 0.08
ND
2.19 ± 0.17
a
5.75
abc
2.09a ± 0.08
ND
21.91 ± 0.40
ND
4.43 ± 0.09 36.73a ± 0.30
a
3.98a ± 0.20
12.82
cd
2.86 ± 0.05
ND
Belly part
d
± 0.13
± 0.43
± 0.30 34.59 ± 0.60
d
19.88 ± 1.11
b
12.71
ab
59.13a ± 0.50
6.27f ± 0.17
3.98b ± 0.18
3.22e ± 0.10
0.87ab ± 0.07
ND
2.00
bc
5.51
bc
1.91bc ± 0.06
ND
19.01 ± 0.25
d
3.69a ± 0.24
4.01 ± 0.06 36.90a ± 0.90
cd
3.93a ± 0.120
12.70 ± 0.20
d
2.26 ± 0.10
ND
Trimmed muscle
n-Hexane extracted oils
ND Not detected, SD Standard deviation. Means with different superscripts in the same row differ significantly (P \ 0.05)
35.14
cd
20.76 ± 1.4
12.26 ± 0.48
cd
3.62
3.85bc ± 0.13
Docosahexanoic Acid (C22:6n3) P SFA P MUFA P x-3 PUFA P x-6 PUFA P PUFA a
4.54a ± 0.12
3.17e ± 0.12
Eicosapentanoic Acid (C20:5n3)
ab
0.81b ± 0.09
0.91ab ± 0.15
Docosadienoic Acid (C22:1n9)
± 0.11
0.53ab ± 0.11
0.61a ± 0.14
Eicosatrienoic Acid (C20:3n6)
± 0.07
2.01
bc
5.19 ± 0.16
2.12 ± 0.10
a
5.24 ± 0.20
c
1.82d ± 0.14
ND
22.43 ± 0.40
Eicosadienoic Acid (C20:2)
Linolenic Acid (C18:3n3)
c
1.93abc ± 0.10
± 0.19
Eicosenoic Acid (C20:1)
a
1.11 ± 0.12
19.24
Arachidic Acid (C20:0)
Linoleic Acid (C18:3n6)
a
3.20e ± 0.16
3.53ab ± 0.21
Elaidic Acid (C18:1n9t)
bcd
3.85 ± 0.20 33.39e ± 0.40
de
3.18bc ± 0.15
12.88
cd
2.55 ± 0.10
ND
3.78 ± 0.07 34.35d ± 0.35
de
2.84a ± 0.05
12.59 ± 0.20
d
3.11 ± 0.15
a
1.03b ± 0.11
Belly part
Belly part
Trimmed muscle
SC-CO2 extracted oils
Pressed
Stearic Acid (C18:0) Oleic Acid (C18:1n9C)
Palmitoleic Acid (C16:1)
Palmitic Acid (C16:0)
Mystric Acid (C14:0)
Tridecanoic Acid (C13:0)
Fatty acids (%)
Table 3 Fatty acids composition of pressed, SC-CO2 extracted and n-hexane extracted salmon by-product oils (values are mean ± SD)
± 0.30
± 0.63
± 0.06
± 0.52
cd
± 0.50
35.89
bc
b
± 0.82 ± 0.43
21.03 ± 0.54
12.82
ab
55.77cde ± 1.40
7.77
4.32a ± 0.20
3.85c ± 0.13
0.93ab ± 0.08
0.48b ± 0.13
2.04
bc
5.65
bc
1.87c ± 0.05
b
0.76 ± 0.12
19.89
bc
0.37f ± 0.10
4.41 ± 0.15 36.19ab ± 0.42
ab
4.03a ± 0.03
13.31
ab
2.27d ± 0.15
0.33c ± 0.13
Frame bone
g
± 0.09
35.69
cd
± 1.06
20.64b ± 0.41
12.38ab ± 0.21
56.53bc ± 0.50
8.36bc ± 0.20
3.09
2.79f ± 0.14
1.00a ± 0.08
0.64a ± 0.15
2.10a ± 0.15
6.50a ± 0.25
2.06ab ± 0.10
0.58c ± 0.10
19.00d ± 1.45
3.34cde ± 0.21
4.37ab ± 0.15 35.34bc ± 0.61
3.16c ± 0.02
13.2bc ± 0.10
2.84b ± 0.08
ND
Skin
Waste Biomass Valor
Waste Biomass Valor
case of DHA (C22:6n3) content, hexane extracted frame bone oils showed the highest percentage (4.32 ± 0.20 %) and hexane extracted skin oils showed the lowest percentage P (3.09 ± 0.09 %). The total saturated fatty acids ( SFA) in salmon by-products oil differ significantly and the highest value was showed in pressed belly part oil (11.00 ± 0.50 %) and the lowest value was obtained in SC-CO2 extracted belly part oils (6.4 ± 0.60 P %). The total amount of monounsaturated fatty acid ( MUFA) constituents in the different byproduct oils of salmon was found to be higher (54.24 ± 1.0–59.13 ± 0.50 %) than either saturated fatty acid (SFA) or PUFA. There was difference among the total P omega-3 polyunsaturated fatty acids ( x-3 PUFAs) of various salmon by-product oils but the difference was not signified on the basis of sample/extraction method. The P highest x-3 PUFAs was found in SC-CO2 extracted skin oils (13.40 ± 0.40 %) followed by SC-CO2 extracted belly part oil (13.35 ± 0.32 %), frame bone (13.23 ± 1.2 %) and hexane extracted frame bone oils (12.82 ± 0.82 %). The P lowest x-3 PUFAs was found in hexane extracted belly part oil (12.10 ± 0.29 %). The total omega-6 polyunsatuP rated fatty acids ( x-6 PUFAs) of various salmon byproducts oil were also different but they cannot be categorized significantly based on sample/extraction method. The P x-6 PUFAs content varied between 19.88 ± 1.11 (nhexane extracted trimmed muscle oil) and 23.77 ± 0.49 % (SC-CO2 extracted belly part oils). x-3 and x-3 PUFAs are highly prone to oxidation and the amount is influenced by partial oxidation due to extraction process. Mostly, SC-CO2 extracted oils showed lower PAV/POV, and higher x-3 and x-6 PUFAs which indicates lesser extent of oxidation in SCCO2 extracted oil. SC-CO2 extracted belly part oil contained the highest amount of total polyunsaturated fatty acids P ( PUFAs) 39.13 ± 0.25 % followed by the SC-CO2 extracted trimmed muscle (39.0 ± 0.38 %), n-hexane extracted belly part (37.30 ± 0.49 %) and SC-CO2 extracP ted skin (36.11 ± 1.02 %) oil. The PUFAs of SC-CO2 extracted belly part, trimmed muscle and skin oils were significantly higher than hexane extracted oils whereas there was no significant difference in case of SC-CO2 and n-hexane extracted frame bone oil. However, the differences in the percent of total SFA, MUFA, PUFA (x-3 and x-6) extracted from the different by-products of Atlantic salmon were significant but there was no homogeneity in grouping among by-product samples or extraction methods. Fatty acid compositions of Indian mackerel oil extracted from different parts using of SC-CO2 and solvent extraction and reported no significant differences in fatty acid compositions among the obtained oils [64]. No significant difference among the fatty acids obtained by solvent and SC-CO2 from by-products of tuna [45]. There was no previous research report found regarding fatty acid composition analysis relevant to the research of Atlantic salmon by-products.
Conclusions Salmon by-product is rich source of marine lipid feasible to use for polyunsaturated fatty acid (PUFA) rich edible oil production for the consumption of human and other pet animals. Premium quality oil of physical, biochemical and biological potential rich in PUFA can be extracted by using SC-CO2 technology from salmon by-products. The UK dietary guidelines for cardiovascular disease acknowledge the importance of long chain omega-3 PUFAs and it was recommended for increasing the average x-3 PUFA intake from 0.1 to 0.2 g/day [65]. The increased demand for marine lipid is possible to mitigate by using oil from fish by-products. The most important advantage of using fish by-products oil is that, this oil is much cheaper compared with the oil extracted from fish flesh. Applications of salmon by-products for edible oil production possess feasibility of valorization of fish wastes, meeting the increased nutritional requirement and reducing environmental pollution. Acknowledgments The authors gratefully acknowledge the financial support for the research work provided by Business for Cooperative R&D (Grant No. C0350298) between Industry, Academy and Research Institute funded Korea Small and Medium Business Administration in 2015.
References 1. Falch, E., Rustad, T., Aursand, M.: By-products from gadiform species as raw material for production of marine lipids as ingredients in food or feed. Process Biochem. 41, 666–674 (2006) 2. Hamilton, M.C., Hites, R.A., Schwager, S.J., Foran, J.A., Knuth, B.A.: Lipid composition and contaminants in farmed and wild salmon. Environ. Sci. Technol. 39, 8622–8629 (2005) 3. Chin, J.P.F., Dart, A.M.: How does fish oil affect vascular function clinic. Exp. Pharmacol. 22, 71–81 (1995) 4. Middaugh, J.P.: Cardiovascular deaths among Alaskan natives, 1980–1986. Am. J. Public Health 80, 282–285 (1990) 5. Newman, W.P., Middaugh, J.P., Propst, M.T., Roger, D.R.: Atherosclerosis in Alaska natives and non-natives. Lancet 341, 1056–1057 (1993) 6. Shahidi, F., Miraliakbari, H.: Omega-3 (n-3) fatty acids in health and disease: part 1—cardiovascular disease and cancer. J. Med. Food 7, 387–401 (2004) 7. Hoffman, D.R., Uauy, R.: Essentiality of dietary omega-3 fatty acid for premature infants: plasma and red blood cell fatty acid composition. Lipids 27, 886–896 (1992) 8. Aryee, A.N.A., Simpson, B.K.: Comparative studies on the yield and quality of solvent extracted oil from salmon skin. J. Food Eng. 92, 353–358 (2009) 9. Tso, M., Lam, T.: Method of Retarding and Ameliorating Central Nervous System and Eye Damage. U.S. Patent #5527533 (1996) 10. Philipp, J.H., Nouard, M.L., Jacobsen, C.: Fish oil extracted from fish-fillet by-products is weakly linked to the extraction temperatures but strongly linked to the omega-3 content of the raw material. Eur. J. Lipid Sci. Technol. 117, 1–11 (2015) 11. European Union Council: Outcome of the Council Meeting— 3360th Council meeting—Agriculture and Fisheries, Brussels (2014)
123
Waste Biomass Valor 12. Jacobsen, C.N., Horn, N.S., Sørensen, A.M., Bimbo, A.B.: Food Enrichment with omega-3 Fatty Acids, p. 107. Woodhead Publishing Limited, Cambridge (2013) 13. Staby, A., Mollerup, J.: Separation of constituents of fish oil using supercritical fluids: a review of experimental solubility, extraction, and chromatographic data. Fluid Phase Equilib. 91, 349–386 (1993) 14. Le´tisse, M., Rozie`res, M., Hiol, A., Sargent, M., Comeau, L.: Enrichment of EPA and DHA from sardine by supercritical fluid extraction without organic modifier: optimization of extraction conditions. J. Supercrit. Fluids 38, 27–36 (2006) 15. Lee, J.H., Asaduzzaman, A.K.M., Yun, J.H., Chun, B.S.: Characterization of the yellow croaker Larimichthys polyactis muscle oil extracted with supercritical carbon dioxide and an organic solvent. Fish Aquat. Sci. 15, 275–281 (2012) 16. Rubio-Rodriguez, N., de Diego, S.M., Beltran, S., Jaime, I., Sanz, M.T., Rovira, J.: Supercritical fluid extraction of the omeg-3 rich oil contained in hake (Merluccius capensis-Merluccius paradoxus) byproducts: study of the influence of process parameters on the extraction yield and oil quality. J. Supercrit. Fluid 47, 215–226 (2008) 17. AOCS Official Method Cd 3d-63: Acid value in fats and oils. American Oil Chemists’ Society, Champaign, Illinois, USA (2006) 18. AOCS Official Method Cd 8-53: Peroxides in fats and oils. American Oil Chemists’ Society, Champaign, Illinois, USA (2006) 19. AOCS Official Method Ca 5a-40: Free fatty acids. American Oil Chemists’ Society, Champaign, Illinois, USA (2006) 20. AOCS Official Method Cd 18-90: p-Anisidine value. Sampling and analysis of commercial fats and oils. American Oil Chemists’ Society, Champaign, Illinois, USA (2006) 21. Farhoosh, R.: The Effect of operational parameters of the Rancimat method on the determination of the oxidative stability measures and shelf-life prediction of soybean oil. J. Am. Oil Chem. Soc. 84, 205–209 (2007) 22. Blois, M.S.: Antioxidant determinations by the use of a stable free radical. Nature 26, 1199–1200 (1958) 23. Zheleva-Dimitrova, D., Nedialkov, P., Kitanov, G.: Radical scavenging and antioxidant activities of methanolic extracts from Hypercium species growing in Bulgaria. J. Pharm. 6, 74–78 (2010) 24. Oyaizu, M.: Studies on product of browning reaction prepared from glucose amine. Jpn. J. Nutr. 44, 307–315 (1986) 25. Beara, I.N., Lesjak, M.M., Jovin, E.D., Balog, K.J., Anackov, G.T., Orc´ic´, D.Z., Mimica-Dukic´, N.M.: Plantain (Plantago L.) species as novel sources of flavonoid antioxidants. J. Agric. Food Chem. 57, 9268–9273 (2009) 26. AOCS Official Method Ce 1-62: Fatty acid composition by gas chromatography. American Oil Chemists’ Society, Champaign, Illinois, USA (2006) 27. Haque, A.S.M.T., Asaduzzaman, A.K.M., Chun, B.S.: fatty acid composition and stability of extracted mackerel muscle oil and oil-polythene glycol particles formed by gas saturated solution process. Fish Aquat. Sci. 17(1), 67–73 (2014) 28. Guerin, M., Huntley, M.E., Olaizola, M.: Haematococcus astaxanthin: applications for human health and nutrition. Trends Biotech. 21, 210–216 (2003) 29. Ohgami, K., Shiratori, K., Kotake, S., Nishida, T., Mizuki, N., Yazawa, K., Ohno, S.: Effects of astaxanthin on lipopolysaccharide-induced inflammation in vitro and in vivo. Invest. Ophthalmol. Vis. Sci. 44, 2694–2701 (2003) 30. Fassett, R.G., Coombes, J.S.: Astaxanthin in cardiovascular health and disease. Molecules 17, 2030–2048 (2012) 31. Bjerkeng, B.: Carotenoid pigmentation of salmonid fishes—recent progress. Advances in Nutrition Symposium, World Aquaculture Society, Mexico, 19–22 November (2000)
123
32. Sathivel, S.: Thermal and flow properties of oils from salmon head. J. Am. Oil Chem. Soc. 82, 147–150 (2005) 33. Noriega-Rodriguez, J.A., Ortega-Garcı´a, J., Angulo-Guerrero, O., Garcı´a, H.S., Medina-Jua´rez, L.A., Ga´mez-Meza, N.: Oil production from sardine (Sardinops sagax caerulea). CyTA J. Food 7, 173–179 (2009) 34. Bimbo, A.P.: Guidelines for characterizing food grade fish oil. International fish meal and oil manufacturers association. Res. Rep. 9, 473–483 (1998) 35. Suseno, S.H., Yang, T.A., Nadiahbt, W., Abdullah, W., Saraswati, : Physico-chemical characteristics and quality parameters of alkali-refined lemuru oil from Banyuwangi, Indonesia. Pak J. Nutr. 14, 107–111 (2015) 36. Zahir, E., Saeed, R., Hameed, M.A., Yousuf, A.: Study of physicochemical properties of edible oil and evaluation of frying oil quality by Fourier transform-infrared (FT-IR) spectroscopy. Arab. J. Chem. (2014) 37. Farag, R.S., Basuny, A.M.M.: Improvement in the quality of used sunflower oil by organic and inorganic adsorbents. Int. J. Food Sci. Technol. 44, 1802–1808 (2009) 38. Rubio-Rodriguez, N., de Diego, S.M., Beltran, S., Jaime, I., Sanz, M.T.: Supercritical fluid extraction of fish oil from fish byproducts: a comparison with other extraction methods. J. Food Eng. 109, 238–248 (2012) 39. Deepika, D., Vegneshwaran, V.R., Julia, P., Sukhinder, K.C., Sheila, T., Heather, M., Wade, M.: Investigation on oil extraction methods and its influence on omega-3 content from cultured salmon. J. Food Process. Technol. 12, 1–13 (2014) 40. Wrolstad, R.E., Decker, E.A., Schwartz, S.J.: Handbook of food analytical chemistry, water, proteins, enzymes, lipids, and carbohydrates. Science (2005) 41. Boran, G., Karacam, H., Boran, M.: Changes in the quality of ash oils due to storage temperature and time. Food Chem. 98, 693–698 (2006) 42. Alberta, N.A., Benjamin, A., Simpson, K., Phillip, L.E., Cue, R.I.: Effect of temperature and time on the stability of salmon skin oil during storage. J. Am. Oil Chem. Soc. 89, 287–292 (2012) 43. FAO/WHO: Joint FAO/WHO food standards program codex committee on fats and oils. Proposed draft standard for fish oils. Langkawi, Malaysia. 23rd session (2013) 44. GOED: GOED Voluntary Monograph. Global Organization for EPA and DHA, Salt Lake City (2014) 45. Sahena, F., Zaidul, I.S., Nik, N., Alexandra, O., Kamruzzaman, Y., Ahmed, J.C., Jahirul, A., Mohd, O.: Quality of tuna fish oils extracted from processing the by-products of three species of neritic tuna using supercritical carbon dioxide. J. Food Proces. Preser. 39, 432–441 (2014) 46. Aidos, I., Padta, V.D., Boom, R.M., Luten, J.B.: Upgrading of maatjes herring by-products: production of crude fish oil. J. Agric. Food Chem. 49, 3697–3704 (2001) 47. Huss, H.H.: Fresh fish, quality and quality changes. FAO Fisheries No. 29 (1988) 48. Ritter, J.S.: Chemical measures of fish oil quality: oxidation products and sensory evaluation. Doctor of Philosophy Thesis Desertion, Dalhousie University, Halifax, Nova Scotia, Canada (2012) 49. Sullivan, J.C., Budge, S.M.: Monitoring fish oil volatiles to assess the quality of fish oil. Lipid Technol. 22, 230–232 (2010) 50. Chantachum, S., Benjakul, S., Sriwirat, N.: Separation and quality of fish oil from precooked and non-precooked tuna heads. Food Chem. 69, 289–294 (2000) 51. Jung, G.W., Kang, H.M., Chun, B.S.: Characterization of wheat bran oil obtained by supercritical carbon dioxide and hexane extraction. J. Ind. Eng. Chem. 18, 360–363 (2012) 52. Niki, E.: a-Tocopherol. In: Cadenas, E., Packer, L. (eds.) Handbook of Antioxidants, pp. 3–25. Marcel Dekker, New York (1996)
Waste Biomass Valor 53. Refsgaard, H.H.F., Brockhoff, P.B., Jensen, B.: Biological variation of lipid constituents and distribution of tocopherols and astaxanthin in farmed Atlantic salmon (Salmo salar). J. Agric. Food Chem. 46, 808–812 (1998) 54. Mortensen, A., Skibsted, L.H.: Antioxidant activity of carotenoids in muscle foods. In: Decker, E.A., Faustman, C., LopezBote, C.J. (eds.) Antioxidants in Muscle Foods, pp. 61–309. Wiley, New York (2000) 55. Liang, J., Tian, Y.X., Yang, F., Zhang, J.P., Skibsted, L.H.: Antioxidant synergism between carotenoids in membranes. Astaxanthin as a radical transfer bridge. Food Chem. 115, 1437–1442 (2009) 56. Schiedt, K., Leuenberger, F.J., Vecchi, M.: Natural occurrence of enantiomeric and meso-astaxanthin. 5. Ex wild salmon (Salmo salar and Oncorhynchus). Helv. Chim. Acta 64, 449–457 (1981) 57. Burton, G.W., Ingold, K.U.: b-Carotene: an unusual type of lipid antioxidant. Science 224, 569–573 (1984) 58. Britton, G.: Structure and properties of carotenoids in relation to function. FASEB J. 9, 551–1558 (1995) 59. Yousry, M.A.N.: Antioxidant activities of astaxanthin and related carotenoids. J. Agric. Food Chem. 48, 1150–1154 (2000)
60. Miki, W.: Biological functions and activities of animal carotenoids. Pure Appl. Chem. 63, 141–146 (1991) 61. Saito, H., Ishihara, K.: Antioxidant activity and active sites of phospholipids as antioxidants. J. Am. Oil Chem. Soc. 74, 12 (1997) 62. Pokorny´, J.: Major factors affecting the autoxidation of lipids. In: Chan, H.W.-S. (ed.) Autoxidation of Unsaturated Lipids, pp. 141–206. Academic Press, London (1987) 63. Ted, H.W., Bechtel, P.J.: Salmon by-product storage and oil extraction. Food Chem. 111, 868–871 (2008) 64. Sahena, F., Zaidul, I.S.M., Jinap, S., Yazid, A.M., Khatib, A., Norulaini, N.A.N.: Fatty acid compositions of fish oil extracted from different parts of Indian mackerel (Rastrelliger kanagurta) using various techniques of supercritical CO2 extraction. Food Chem. 120, 879–885 (2010) 65. Ruxton, C.H.S., Reed, S.C., Simpson, M.J.A., Millington, K.J.: The health benefits of omega-3 polyunsaturated fatty acids: a review of the evidence. J. Hum. Nutr. Diet. 17, 449–459 (2004)
123
