Processing of marine oils - from catch to final product

Transcription

1 Temadag: Marine lipider fra fisk til færdigvare, 25.juni, Aarhus Processing of marine oils - from catch to final product Research Manager Ana Carvajal, PhD SINTEF Fisheries and Aquaculture 1

2 Outline The fish oil and fish meal market Marine sources for oil production Processing of marine oils Production Refining Improve utization of available raw material A case from Norway 2

3 Production of fish oil and fish meal Source: FAO Globefish Quarterly Update April Fishmeal and Fish Oil 3

4 Imports of fish oil 4

5 Value chain marine oils FRESH RAW MATERIAL FROM NORWAY Cut-offs from salmon, cod liver or fish from Norway CRUDE OIL IMPORTED TO NORWAY Fish rich in omega-3 acids from South America or Morocco CONCENTRATED FISH OIL PRODUCED IN NORWAY OR ELSEWHERE Crude oil Crude oil Refined oil Refined oil Concentrating Bottling or encapsulation Refined oil containing 15 28% n-3 fatty acids Bottling or encapsulation Refined oil containing ca. 30% n-3 fatty acids Bottling or encapsulation Concentrated omega-3 products

6 Marine sources for production of oils Can be divided in four categories Peruvian anchoveta Fish caught for fish meal/fish oil production Fish by-products/rest raw material from the processing industry Cod liver (from Gadus morhua L. or other gadidae species) Other marine resources (seal, krill, etc.) Krill Salmon by-products Herring by-products 6

7 Fatty acid composition in different raw material 7

8 Processing of marine oils 8

9 Production of marine oils Traditional fish oil and meal production (wet-rendering method) Enzymatic protein hydrolysis 9

10 Raw material quality Oil quality depend on the sorting, storage and handling of the raw material Marine by-products (cut-offs) are especially vulnerable for spoilage and degradation Blood and viscera, high amount of endogenous enzymes Lipases and phospholipases will lead to the formation of free fatty acids decrease oil quality Lipid oxidation promoted by hemoglobin Microbial spoilage Peruvian anchoveta Salmon by-products 10

11 Cooking Minced fish or by-products are transferred to a continous cooker, steam heated to C for aprox min Cooker: Long, steam-jacket cylinder, raw material is moved by a heated rotary screw conveyer (20 min procedure) Scraped surface heat exchanger (less than 2 min) 11

12 Pressing Heated material is transferred to a screw press The liquid ('press liqour') is squeezed from the solid phase ('press cake'), remove as much liquor as possible Optimal pressing: higher oil yield and a fish meal with low oil content Press liquid: water, dissolved materials and oil Press cake: % of oil free dry matter 12

13 Separation of press liquor Press liquor passed over a vibrating screen (5-6 mm perforation) to remove unwanted particles and bones Separation of the different phases (oil, water and remaining solids) based on their spesific gravitation 1. Decanter (horizontal centrifuge) remove fine suspended solids from the liquor 2. Centrifuge oil and water phase is separated into oil and stick water (water soluble components) 3. Polishing centrifuge oil Evaporator stick water Alternative technique: Tri-canter 13

14 Oil polishing Remove final traces of moisture and impurities in the oil Reduces amount of pro-oxidants present in the oil -> increased stability Oil pumped into storage tanks Final product is called crude fish oil 14

15 Drying of press cake fish meal Sludge from the press liquor, press cake and concentrated stick water is mixed together Press cake is dried to reduce the moisture content Possible to use two different types of dryers: direct and in-direct In-direct dryers is used in the Norwegian fish oil and fish meal industry 15

16 Enzymatic protein hydrolysis Based on the use of commercial proteases for proteolytical clevage of peptide bonds, facilitating the degradation of the fish tissue and the release of oil Lower cooking temperature (50 60 C) compared to the traditional fish oil and meal process (90 95 C), can give an oil of higher quality and stability 16

17 Enzymatic protein hydrolysis A hydrolysis stage is implemented after the material is minced The reaction can take place in either a reactor or a screw-mixing pipe reactor Raw material (whole fish or cut-offs) is transferred to the tank and mixed with water (1:1) and enzyme ( % of raw material weight) Hydrolysis time: minutes Enzyme inactivation at 90 C for several minutes (usually > 85 C for 10 min) Separation into 3 phases: oil, fish protein hydrolysate (FPH) and sediments/sludge 17

18 Enzymatic protein hydrolysis commercial enzymes Several commercial enzymes (proteases) are available for enzymatic protein hydrolysis of fish and fish by-products Endoproteases Attacks the proteins and peptides within the molecule by cleavage of internal bonds within the polypeptide chain Smaller peptides, low degree of free amino acids Alcalase (Novozyme), Protamex (Novozyme) and Papain (Enzybel) Exoproteases Attacks only near the end of the polypetide Flavourzyme (Novozyme) 18

19 Enzymatic hydrolysis process parameters Several factors can influence the hydrolysis process Substrate type and properties Enzyme type and properties Processing conditions Hydrolysis temperature Hydrolysis time ph Amount of water added Amount of enzyme added These factors are important for the yield and quality of the product and need to be controlled during processing 19

20 Refining of fish oil Crude fish oils contains minor amount of water and unwanted substances Needs to go through refining before it can be used for human consumption The refining process can include the following steps: - Neutralisation - Washing - Bleaching - Winterisation - Deodorisation - Molecular distillation/ Short path distillation 20

21 Neutralisation/De-acidification Removal of free fatty acids and water soluble compounds Process Oil heated to C Mixed with aqueous sodium hydroxide (NaOH) Settling, followed by discharge of soap fraction Mixed with water Water discharge Drying Batch de-acidification 21

22 Bleaching Removal of pigments, secondary oxidation products, vitamins, environmental pollutants, other polar components Process Heating to C Drying to a water content < 0.2 % Addition of bleaching earth (synthetic bleaching earths, active carbon or silicates) Stirring at C for minutes Filtration Polishing Filter press 22

23 Deodorisation Removal of volatile components, secondary oxidation products and persistent organic pollutants Process Steam distillation High temperatures up to 250 C Low pressures 3 8 mbar Batch or continuous Deodorisation batchwise 23

24 Quality criteria for marine oils for human consumption The chemical composition and quality of the crude oils depend on both the production process and quality of the raw material Composition and quality of the oil will influence their edible properties and technical use No standard quality criteria are set for the crude oils. However, the quality of the crude oil will decide the range of application for the oil and how extensive refining is required 24

25 Quality criteria for marine oils for human consumption Recommendation criteria's for refined oils are available based on the peroxide value (primary oxidation products) and anisidine value (secondary oxidation products) 25

26 Need for new omega-3 sources and more valuable utilization of the raw material Bimbo, A. (2013): Estimated sales of omega-3 products (EPA/DHA oils, low concentrates, middle concentrates and high concentrates) for

27 Marine by-products Defined a products that are not regarded as ordinary saleable products, but can be sold after further treatment* Estimated to make up around 75 % of the total catch** Contain valuable lipid and protein fractions, in addition to other components as nucleic acids, calcium and phosphorus Ingredients for human consumption if treated correctly *Rustad et al., 2011 **Torres et al., 2007 Salmon by-products Herring by-products 27

28 Utilization of marine by-products in Norway 28

29 Herring by-products a source of omega-3 and protein for human consumption? In 2012, T of by-products were generated from the Norwegian herring and mackerel industry (*) As much as 98 % of the herring by-products are currently being used But they are mainly used for production of silage (preservation with formic acid) or ordinary fish oil and fish meal for animal and fish feed. Filleting factories receive herring of food grade quality By treating the by-products in the same way, they can be used to make products for human consumption (*) Olafsen, T., Richardsen, R., Nystøyl, R., Strandheim, G. and Kosmo, J. P. (2012). Analyse av marint restråstoff, 2012, FHF.

30 3 900 T n-3 lipids T lipids Herring by-products T ~ 43 million people could get their daily recommended intake (250 mg (EFSA)) for a whole year around ~ 2.35 mill people could get their daily recommended intake for a whole year around T proteins

31 High quality herring oil from fresh by-products Crude oil (thermal treatment) Crude oil (enzymatic hydrolysis) Commercial crude oils* Silage FFA 0.2 % 0.4 % GOED (refined oils) PV 1.9 ± ± AV 0.7 ± ± TOTOX FFA free fatty acids, % PV peroxide value, meq peroxide/kg oil AV- anisidin value Totox = PV x 2 + AV OSI was measured at 70⁰C GOED Global Organization for EPA and DHA * In Long chain omega-3 oils, H, Breivik,2007 **salmon oil, earlier studies

32 Oils from fresh by-products versus imported South American crude oil Has a lower content of EPA and DHA But Fresh raw material -> High quality oil and protein Reduced transportation and storage period Possible to trace the product through the whole value chain Additional source of lipids and proteins 32

33 Thank you for your attention! 33

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