Effect of frozen storage time and
temperature on quality of Atlantic mackerel (Scombrus scomber)
Paulina E. WasikPhD student Matís ohf. & University of Iceland
Dr. Magnea G. KarlsdottirResearch Group Leader Matís ohf.
Dr. Hordur G. KristinssonChief Science Officer Matís ohf. & Adjunct Associate Professor University of Florida
Sigurjon ArasonChief Engineer Matís ohf. & Professor University of Iceland
Atlantic Mackerel (Scombrus scomber)
� Atlantic mackerel
(Scombrus scomber)
is known from
widespread
relocations and has
been discovered in
Icelandic waters
since 2006 and
gained great
• Losses in:•PUFA
•Vitamins A, D, E•Antioxidants
•Off odor•Off flavor•Discoloration•Undesirable texture
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economical
importance
� Frozen storage of the
mackerel is main
long term
preservation method
� Main quality changes
of the seafood occurs
due to lipid oxidation
Source: Statistics Iceland
•Decrease in:• Emulsifying
activity•Proteins solubility
•Generation of:•Hydroperoxides•Aldehydes•Dimers• Trans fatty acids•Millard type products
texture
Sensory aspects
Nutritional values
TechnologicalToxicity
Factors affecting lipid oxidation development during frozen storage
� Seasonal variation
� Geological variation of fishing
grounds
� Fish processing of raw material
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� Fish processing of raw material
� Freezing methods
� Frozen storage time
� Frozen storage temperature
Main methods
� Lipid oxidation: PV (1°), TBARS (2°), and
fluorescence intensity (3°)
� Enzymatic activity: FFA
Physical and chemical properties
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� Physical and chemical properties: Colour, drip,
water content, lipid content, lipid composition
� Alternative methods: NIR spectroscopy,
colorimetric
� Quality evaluation: texture, appearance, gaping,
blood spots, peritoneum deterioration
The effect of storage temperature on fish quality and stability of lipids
-18 °C
-25 °C
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Free fatty acids (FFA) level were significantly
higher for samples stored at -18˚C than -25˚C
The effect of storage temperature on fish quality and stability of lipids
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Primary oxidation products were at significantly
higher level for samples stored
at -18˚C than -25˚C
The effect of storage temperature on fish quality and stability of lipids
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Secondary oxidation products were at significantly
higher level for samples stored
at -18˚C than -25˚C
Effect of different storage temperature on fish muscle quality
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-25˚C, 12m -18˚C, 12m
Conclusions
� Different pathways of lipid degradation
� Storage temperature and time are important factors regarding oxidative stability of frozen fish products
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products
� Recommended to store at -25 °C instead of -18 °C
Acknowledgment