Effects of processing on nutritional value of fish products Assoc. Prof. Sabine Sampels, Ph.D.

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1 Funded by the European Union s Seventh Framework Programme Effects of processing on nutritional value of fish products Assoc. Prof. Sabine Sampels, Ph.D.

Nutritional value of fish Fish are a good source of the

More recently also the fish proteins have come into focus and

minerals and vitamins (phosphorus, calcium, iron, zinc,

2 Nutritional value of fish Fish are a good source of the essential long chain n-3 polyunsaturated fatty acids (PUFA) More recently also the fish proteins have come into focus and scientific interesst Fish are also a good source of certain minerals and vitamins (phosphorus, calcium, iron, zinc, selenium, iodine (marine species), vitamine D and B 12 as well as Vitamin A

Fatty acids and nutrition Energy source PUFA have an important function in the cell membranes n-3 and n-6 fatty acids are precursors of eicosanoids with important functions in the human body A low

3 Fatty acids and nutrition Energy source PUFA have an important function in the cell membranes n-3 and n-6 fatty acids are precursors of eicosanoids with important functions in the human body A low ratio of n-6/n-3 prevents cardiovascular diseases -> Recommendation for humans: n-6/n-3 = 1-4 Mammals can not synthetize 18:3n-3 and 18:2n-6 and have only limited ability to elongate these towards the longer chain derivatives.

4 Parameters influencing the fatty acid composition in fish muscle Species Season Feeding strategies Handling, transport Storage conditions Preservation and processing techniques Preparation

5 From raw material to ready product Preservation/storage stability Creating a new product Microbial hazards Effects of processing oxidation: cutting, light, heat, salt... Effects on nutritional composition Addition of various ingredients...

6 Frozen storage During freezing ice crystalls are formed. Big crystalls can destroy the cellmembranes > lead to increased enzymatic breakdown and thereby to increased oxidation during thawing since free fatty acids oxidize more easy Oxygen can easier reach the phospholipids in the membranes and cellorganells Decrased binding of water -> increased losses The faster the freezing process, the smaller the crystalls will be -> new freezing techniques!

7 Freezing Micrographs of unfrozen and frozen Atlantic salmon tissues. Alizadeh E, et al ;doi: /j.ifset

Freezing and thawing Prevention of lipidoxidation in longtime-frozen chicken by addition of oregano-oil and α-tocopherylacetate (A) (B) Directly after thawing; After 7 days of cooled storage Food

8 Freezing and thawing Prevention of lipidoxidation in longtime-frozen chicken by addition of oregano-oil and α-tocopherylacetate (A) (B) Directly after thawing; After 7 days of cooled storage Food Research International Volume 36, Issue 3, 2003, Pages Thawing should be done slowly at refrigerated temperatures (< 4 C). Thawing at this temperature will allow for the ice crystals to dissipate with minimal structural damage to the meat product. Also, at these temperatures, pathogenic and spoilage microbial growth is minimized

9 Conclusions: The faster the freezing the better Even during frozen storage things happen Do not freeze fish again once it has ben thawed 9

Fast Foods and Products A number of fast foods was chosen

the respective raw products were analysed (Alaska pollock,

..) Additionally for chosen products samples from every

10 Fast Foods and Products A number of fast foods was chosen that busy parents might give to their kids For fish products the respective raw products were analysed (Alaska pollock, saithe, cod...) Additionally for chosen products samples from every processing step from raw to final product were taken Comparison of composition with food composition tabels was performed

11 Fatty acid changes in fish Cod Crispy cod* Fishfingers Cod Fishfingers (white fish) % Fat SFA MUFA :1n :2n :4n nd nd nd 20:5n :5n nd :6n n n n-6/n

Fat and oils -main fatty acids Sunflower Corn Rapeseed Palm Butter lard Oliveoil Safflor 18:1 n-9 14-39 20-42 51-70

12 Fat and oils -main fatty acids Sunflower Corn Rapeseed Palm Butter lard Oliveoil Safflor 18:1 n :2n :3n <

13 Conclusions: Fat content and fatty acid composition in fish products is highly affected by added fat or battering Depending on the used fat the n-3/n-6 balance willbe totally shifted The product will have a significant changed untritional value 13

14 Fish- and liverpaté Porkliver patés: various proportions of liver, porkmeat, pork fat, Milkprotein, flour (rice, wheat) spices... Fishpatés: 25-40% Fish, Milkprotein, potatoemash + potatoestarch, Plantoil, etc...

15 Canned fish- lipid composition Ratio!!!

16 Frying of carp in the traditional way, using different fat sources: Fried plain and with a batter Frying oils (fat): Sunflower, butter, lard, rapeseed Fat content Fatty acids TBARS (lipid oxidation)

17 Fat content in carp fillets raw and after frying

18 Changes in chosen fatty acids due to frying of carp fillets C14:0 C16:0 C18:0 C18:1n9 C18:2n6 C18:3n3 butter fried plain butter fried in batter lard fried plain lard fried in batter rapeseed oil fried plain rapeseed oil fried in batter sunflower oil fried plain sunflower old fried in batter

19 Conclusions Frying will increase the total fat content, frying with a batter results in a three times higher fat content The fatty acid composition of the used fat is mirrored in the product after frying Use of n-6 rich oils (corn, sunflower) will significantly change the nutritional value Recommend to use neutral oil or oil rich in n-3 (oliveoil, rapeseed) 19

Increasing nutritional value of traditional meat products with an underutilized by-products

separate, an underutilized by-product from carp processing.

Method: Replace part of the meat with fish separate in 4 different traditional meat

20 Increasing nutritional value of traditional meat products with an underutilized by-products from carp processing Aims: to develop innovative, novel products using so called carp separate, an underutilized by-product from carp processing. to create attractive products and thereby promote and increase the consumption of fish. Method: Replace part of the meat with fish separate in 4 different traditional meat products : Barbecue sausage, Vienna type sausage, hotdog type sausage and liver pate carp separate barbecue sausages hotdog type sausages

21 Fatty acid composition in commercial versus novel products (%) The amount of combined EPA and DHA was 74, 54, 109 and 77mg/100g in the novel barbecue sausage, Frankfurter type, Vienna type sausage and pâté respectively. (22-31% of the minimal recommended daily intake by EFSA) sausages with fish min-max commercial sausages min-max C14: C16: C16:1trans C16: C18: C18:1n C18:1n C18:2n C18:3n C20:1n C20:4n C20:5n n. d. C22:5n n.d. C22:6n n.d. SFA MUFA PUFA n n n-6/n EPA+DHA n.d.

22 Conclusions Fish by-products can be used in novel combined meat-products and increase their nutritional value 22

23 Fish marinated in various berry concentrates Treatment Marinating 24h in the chosen berry concentrates Vacuum packaging, storage at 4 C for 7 days Frozen storage at - 20 C for 6 months elderberry cranberry black currant

24 Lipid and protein oxidation µm/g (MDA) TBARS P=0.620 P=0.392 P=0.071 K= control 1=elderberry 2=cranberry 3= black currant mm/g protein K Carbonyls P=0.731 P=0.296 P=0.096 K µg/g α-tocopherol P=0.52 P=0.10 P=0.05 k elderberry cranberry black currant

25 Volatile components, deriving from lipid oxidation ng/g Penten-3-ol (rancid flavor) K= control 1=elderberry 2=cranberry 3= black currant ng/g Hexanal P= P=0.105 P= P=0.048 * P=0.036 * P= K K Butanal Penten-1-ol P=0.095 P=0.047 * P= P=0.086 P=0.108 P= K K 1 2 3

26 Colour..

27 Conclusions Natural antioxidants from berry concentrates and other novel additives protect fish against oxidation and increase shelf-life A possible added value from the increased proportion of antioxidants and polyphenols Possibility to design fancy healthy snacks with natural ingredients.

Take home messages how to keep and increase nutritional value

sources high in n-3 FA or ratio neutral fats in processing

use of natural antioxidants for increase shelf life and add

28 Take home messages how to keep and increase nutritional value of fish: Optimize preservation and storage conditions Use fat sources high in n-3 FA or ratio neutral fats in processing Teach people to use right fat for preparation Evaluate the use of natural antioxidants for increase shelf life and add value Communication through the whole production chain is essential!

Faculty of Food Science and Nutrition, University of Iceland, Eiriksgata 29, 101 Reykjavik, Iceland b

Faculty of Food Science and Nutrition, University of Iceland, Eiriksgata 29, 101 Reykjavik, Iceland b Influence of stable and abusive temperatures on lipid deterioration of Atlantic herring (Clupea harengus) light and dark muscle during long-term frozen storage Dang Thi Thu Huong a,c, Maria Gudjonsdottir