experiment to see how best fish can be stored

1. Effects of packaging methods and temperature
on the lipid quality changes of Cobia (Rachycentron
canadum) fillets during frozen storage
Thi Hang Nguyen,
Faculty of Food Science and Nutrition, University
of Iceland, hangnt@ntu.edu.vn

2. Introduction
• Cobia fillets contain:
 Lipid content: 5.3-16.6%
 MUFA: 34%
 PUFA: 15.5%
Cobia lipids may be susceptible to lipid
oxidation during processing and storage
Objectives
 Evaluate effects of air packaging and vacuum
packaging on the quality of cobia fillets during
frozen storage for 5 months.
 Investigate effects of different storage
temperatures (-18 oC and -25 oC) on the quality
of cobia fillets during frozen storage for 5
months.

3. Fig. 1: Flow chart of the
experimental design
Raw materials and methods
Four experimental groups
1. Cobia fillets air packaged and stored at -18 oC (AP, -18 oC)
2. Cobia fillets air packaged and stored at -25 oC (AP, -25 oC)
3. Cobia fillets vacuum packaged and stored at -18 oC (VP, -18 oC)
4. Cobia fillets vacuum packaged and stored at -25 oC (VP, -25 oC).
Analyses
 Water and total lipid (TL) content
 Phospholipid (PL) content
 Free fatty acids (FFA)
 Lipid hydroperoxides (peroxide value, PV)
 Thiobarbituric acid reactive substance (TBARS)
Sampling time: every month up to 5 months of storage

4. Results and Discussion
60
63
66
69
72
75
0 1 2 3 4 5
Watercontent(%)
Storage time (months)
(A)
Fig. 2: Water content (%) (A) and total lipid content (%) (B) in vacuum packaged (VP) and air packaged
(AP) frozen cobia fillets during 5 months frozen storage at -18 oC and -25 oC.
0
3
6
9
12
15
0 1 2 3 4 5
Totallipidcontent(%)
Storage time (months)
(B)

5. Fig. 3: PL content (A) and Free fatty acid (g FFA/100 g TL) (B) in vacuum packaged (VP) and air packaged
(AP) frozen cobia fillets during 5 months frozen storage at -18 oC and -25 oC.
0
1
2
3
0 1 2 3 4 5
Phospholipid(%ofTotallipid)
Storage time (months)
0
1
2
3
4
5
0 1 2 3 4 5
gFFA/100glipid
Storage time (months)
(B)(A)
Results and Discussion

6. Fig. 4: Lipid hydroperoxide (PV; mol/kg muscle) (A) and thiobarbituric acid reactive substance (TBARS; mol
MDA/kg muscle) content (B) in vacuum packaged (VP) and air packaged (AP) frozen cobia fillets during 5 months
frozen storage at -18 oC and -25 oC.
0
20
40
60
80
100
0 1 2 3 4 5
Lipidhydroperoxide
(µmol/kgmuscle)
Storage time (months)
(a)
0
5
10
15
20
25
30
0 1 2 3 4 5
TBARS(µmol/kgmuscle)
Storage time (months)
(A) (B)
Results and Discussion

7. Conclusions
• The farmed cobia was a fatty fish species with 70.9 ± 1.2% moisture and 10.1 ± 0.2% lipid
content
• Several lipid quality changes occurred in all samples during the frozen storage
• The storage time showed the strong effect on lipid hydrolysis and oxidation all frozen cobia
fillets.
• Vacuum packaging significantly reduced lipid oxidation compared to air packaging
• A lower storage temperature had some effective retardations in lipid degradation
• It can be suggested that vacuum packaging in combination with a storage temperature of -18
oC or lower can be applied to remain product stability

8. Thank you for your attention