) and new zealand hoki ( ) liver oil using short-path...

The New Zealand Institute for Plant & Food Research Limited

Purification of Alaskan walleye pollock (Theragra

chalcogramma) and New Zealand hoki (Macruronus

novaezelandiae) liver oil using short-path distillation

Prepared by:

Matt Miller and Alexandra C.M. Oliveira


Assoc. Prof. Alex Oliveira


Kodiak, Alaska, USA


Objectives

Investigate the applicability of short-path distillation to refine crude

pollock oils

Take 7-year-old rancid hoki oil and see if we can make it meet

GOED standard

In general, investigate the applicability of using short path distillation

on marine oils

Add value to respective fisheries


Pollock and Hoki oils

Pollock

Fishery ~ 1 M metric tonnes

Major products

Surimi, boneless skinless fillets

and roe

By-products

Small amount produced

Hoki (Blue grenadier)

Quota ~150,000 metric tonnes

Major products

Boneless skinless fillets, surimi,

and roe

By-products

Fish meal, fish oil, omega 3

concentrates, collagen

products


Fatty acid profiles of pollock and hoki oils

Fatty acid g/100 g Pollock1 Hoki2

SFA 20.0 23.6

18:1n-9 OA 16.8 22.2

20:1n-9 3.4 10.6

Total MUFA 39.6 51.0

20:5n-3 EPA 15.0 6.0

22:6n-3 DHA 5.0 12.4

Total n-3 28.3 23.3

20:4n-6 AA 5.0 0.4

Total PUFA 34.4 26.4

Lipid class g/100 g

TAG 99.8 97.1

PL 0.2 0.7

1Wu TH et al. (2009). JOACS 2Miller MR et al. (2011) JOACS


• Oxidation is a series of negative (chain) reactions that produce off-

flavours and smells in oils

• Polyunsaturated oils are prone to oxidation

• Double bonds are very reactive

• Primary oxidation products (peroxides, dienes, free fatty acids)

• Secondary products

(carbonyls,

aldehydes, trienes)

• Acid value – measures

formation of FFA

Oxidation of oils


GOED Monograph

Acid value. Maximum 3 mg KOH/g; AOCS Official Method Cd 3d-63

Peroxide value. Maximum 5 meq/kg; AOCS Official Method Cd 8-53

Anisidine value. Maximum 20; AOCS Official Method Cd 18-90

TOTOX. Maximum 26 (result of calculation, (2 x PV) + AV)

Plus PCBs, Dioxins, Furans and Dioxin-like PCBs, Heavy Metals


Traditional fish oil purification process

Crude oil

Bottling/

capsules and

storage

DegummingRemoves soluble & insoluble

impurities e.g. proteins,

phospholipids, trace metals

Washing oil with organic acid

& mild heat (e.g. citric acid)

NeutralizationRemove free fatty acids,

water sol material

Wash oil with caustic soda &

mild heat

Bleaching Removes pigments, trace

soaps, sulphur- and

carbonyl-containing

compounds & trace metals

Treat the oil with an

absorbent e.g. activated

earth/carbon, chitosan, etc.

DeodorizationRemoves “fishy” odour

(aldehydes and

ketones) –oxidation

products

Distillation

Winterisation Removes stearines,

waxes, low melting point

TAG

Short path

distillation


Short-path distillation

Pope - Wiped-film distillation

and evaporation process

• Short residence time of the

feed liquid

• Significantly lowered

temperature due to high

vacuum capability


Short-path distillation


0

2

4

6

8

10

12

Crude 190 200 210

me

q/k

g

Hoki oil

Pollock oil

Peroxide value

Temp (oC)


Anisidine value

0

5

10

15

20

25

30

Crude 190 200 210

An

isid

ine

va

lue

Hoki oil

Pollock oil

Temp (oC)


Acid value

0

2

4

6

8

10

12

14

16

Crude 190 200 210

mg

KO

H/g

Hoki oil

Pollock oil

Temp (oC)


Results

Shows potential

Free fatty acids and primary and secondary products of lipid

oxidation were effectively removed from hoki and pollock oils with

SPD to meet GOED standards.

Short-path distillation refines and deodorizes fish oils in a chemical-

free single-step process.

Kodiak is a pretty amazing place.


www.plantandfood.co.nz


[email protected]

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