Bulletin of the Sea Fisheries Institute 1 (155) 2002 - CEEMaR

42
Z. Dobrzañski, P. Bykowski, Z. Iwaniuk, Z. Usydus, H. Górecka and T. Trziszka
Table 2. Acid number (AN) and peroxide number (PN) of fish oil stored under different conditions
Indicator
Unit
Test I (n = 3) Test II a (n = 3) Test III b (n = 3)
Fresh oil Stored 30 days Stored 30 days
AN mg KOH/g 12.5 12.6 13.4
PN meq O 2/kg 6.2 7.4 10.0
a storage at air temp. 10-15°C without exposure to sunlight
b storage at air temp. 21-26°C with exposure to sunlight
Table 3. Fatty acids content (%) in fish oil (FO)
Fatty acid Symbol Mean (n = 3) Range
Myristic C14 : O 3.19 2.92-3.52
Myristoleic C14 : 1 0.11 0.08-0.13
Pentadecanoic C15 : O 0.20 0.16-0.22
Palmitic C16 : O 11.74 10.66-12.04
Palmitoleic C16 : 1 (n = 7) 2.14 1.96-2.32
Heptadecanoic C17 : 0 0.33 0.18-0.45
Margaric C17 : 1 0.26 0.22-0.28
Stearic C18 : O 1.82 1.66-2.02
Oleic C18 : 1 (n = 9) 41.03 38.50-43.66
Vaccenic C18 : 1 (n = 7) 1.95 1.69-2.33
Linoleic C18 : 2 (n = 6) 17.74 17.02-19.11
γ-linolenic C18 : 3 (n = 6) 0.29 0.26-0.32
α-linolenic C18 : 3 (n = 3) 7.01 6.60-7.42
Eicosenoic C20 : 1 1.64 1.59-1.69
Eicosadienoic C20 : 2 0.29 0.24-0.33
Arachidonic C20 : 4 (n = 6) 0.14 0.11-0.17
Eicosapentaenoic C20 : 5 (n = 3) 3.98 3.59-4.36
Docosatetraenoic C22 : 4 (n = 6) 0.08 0.06-0.10
Docosapentaenoic C22 : 5 (n = 3) 0.17 0.14-0.22
Docosahexaenoic C22 : 6 (n = 3) 5.88 4.96-6.84
content of EPA n-3 (omega) was 3.98%, and DHA n-3 was 5.88%, and total PUFA n-3 –
17.04%.
Tables 5 and 6 present the elemental composition of FO. The presence of 5 minerals and
25 trace elements was confirmed. Excluding Cl (0.23%) and Ca (0.047%), concentrations of
Mg, Na and P as well as toxic elements (As, Cd, Hg, F i Pb) were all low.
The average values of fat-soluble vitamins were as follows (in IU/g of oil): A – 458; D 3
–
240; E – 1.21.
The results of OCP tests are presented in Table 7 and indicate that the concentrations of
individual metabolites, i.e. DDD, DDE and DDMU, varied significantly. However, their sum
(Σ DDT) did not exceed 0.35 in test I or 0.15 mg/kg in test II. The PCBs level was similar in
both test series (Tab. 8) and did not exceed 0.20 mg/kg. Some congeners (for example, numbers
28, 52 and 180) occurred in very low concentrations (< 0.01 mg/kg).