Where we are with the mitigation of 2- and 3-MCPD Esters and Glycidyl Esters?

Dr. Frank Pudel

Pilot Pflanzenöltechnologie Magdeburg e.V.

Outline

Oil processing, ester formation and mitigation strategies

Avoiding (removing) precursors

Changing refining parameters

Post refining

Ionic liquid treatment (a new refining process by Evonik)

Value added chain

Farming Transport Storage

Oil mill Transport Storage

Refining Transport Storage

Products

MCPD & Glycidyl Esters

Chemical refining

Water, acid, enzymes

Degumming Gums Lecithin

Steam Deodoriza-

tion Deodorizer

distillate Sterols,

Tocopherols …

Acid, bleaching clay, silica, active carbon, filtration

aids

Bleaching Used bleaching

clay

Water, caustic soda

De-acidification

Soaps Free fatty acids

Physical refining

Water, acid, enzymes

Degumming Gums Lecithin

Steam Deodoriza-

tion Deodorizer

distillate Sterols,

Tocopherols …

Acid, bleaching clay, silica, active carbon, filtration

aids

Bleaching Used bleaching

clay

Factors for ester forming

MCPD Esters Glycidyl Esters

Precursors Cl (organic & inorganic) Lipids (mono-, di-, triglycerides, phophoslipids)

Diglycerides

Process conditions Temperature (> 150°C) Time pH

Temperature (>230°C)

Mitigation strategies

Farming Transport Storage

Oil mill Transport Storage

Refining Transport Storage

Products

MCPD & Glycidyl Esters

Avoiding (removing) of precursors

Removing of esters

Process changes

Importance of raw material

Palm fruits are

not suitable for storage

metabolic processes begin already on the tree (at full ripeness) or directly after harvest

very sensitive against pressure and injuries

Formation of Free fatty acids Diglycerides

Influence of DAGs

0

5

10

15

20

25

0 1 2 3 4 5 6 7 8 9 10

Content of diacylglycerols [%]

3-M

CP

D e

ster

s an

d r

elat

ed

com

pounds

[mg/k

g]

How to get low DAGs

- Harvest at optimal ripeness - Reject damaged material - Do not use loose fruits - Process (sterilization) as quick as possible (3-6 hours)

Zieverink et al., 8th EFL Congress, Munich, 2010

- Choice / Breeding of varieties poor in lipase activity (?)

Ebongue et al., EJLST 110 (2008) 505-509

Influence of chloride

(TBAC = tetra-n-butyl ammonium chloride)

Added amound of chloride [mg/kg]

R2= 0,9799

0

1

2

3

4

5

6

0 1 2 3 4 5 6 7 8 9 10 11

3-M

CP

D e

ster

s an

d r

elat

ed

com

po

un

ds

[mg

/kg]

Chloride added as NaCl solution

Chloride added as TBAC

R2= 0,9252

How to get low Cl

Minimize the use of chloride containing substances in cultivation - Fertilizers - Pesticides - Irrigation water Avoid cultivation on saline soils

Destaillats et al., Food Additives & Contaminants 1 (2012) 29-37; Craft et al., Food Additives & Contaminants 29 (2012) 354-361; Abdollah, TU Malaysia, 2010

Influence of pH

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

5.0 5.5 6.0 6.5 7.0 7.5 8.0

Acid degumming (0.1 % H3PO4) Water degumming (2.0 % Wasser)

pH of bleaching clay

3-M

CP

D E

ster

[m

g/k

g]

Ramli et al., 2011

Influence of bleaching clay amount 3

-MC

PD

est

ers

an

d r

elat

ed c

om

po

un

ds

[mg

/kg]

degummed: 0.2 % H2O bleached: 1 % BE deodorized: 250 °C, 60 min

CPO, deodorized

250°C; 60 min

0

1

2

3

4

5

6

degummed: 0.2 % H2O Bleached: 3 % BE; deodorized: 250 °C, 60 min

Influence of deodorization temperature and time

1 2 4

180

1 2

210

4 1 2

240

4 1 2

270

4

conte

nt

[mg/k

g]

0

5

10

15

20

25

30

35

40

45

50 Glycidyl esters 3-MCPD esters

time[h]

temperatur [°C]

2-step deodorization – Effect on 3-MCPD esters

°C

min

280

20

280

20

280

20

280

20

280

5

280

5

280

5

280

5

240

20

240

20

240

20

240

20

240

5

240

5

240

5

240

5

°C

min

230

120

230

60

200

120

200

60

230

120

230

60

200

120

200

60

230

120

230

60

200

120

200

60

230

120

230

60

200

120

200

60

AV

(High/low)

0.14 0.09 0.09 0.04 0.08 0.19 0.53 1.98 0.08 0.11 0.17 0.54 0.11 0.89 1.09 2.86

AV

(Low/high)

0.21 0.45 0.5 0.3 0.18 0.6 0.53 0.65 0.09 0.62 1.19 1.47 0.07 0.53 0.74 2.31

3-M

CP

D-F

E [m

g/k

g]

3-MCPD-FE bei einstufiger Desodorierung 3,15 ppm

high temp. / low temp. low temp. / high temp.

3-MCPD-FE content for one step standard deodorization: 3.2 mg/kg

2-step deodorization – Effect on Glycidyl esters G

-FE

[m

g/k

g]

G-FE content for one step standard deodorization: 6.2 mg/kg

high temp. / low temp. low temp. / high temp.

°C

min

280

20

280

20

280

20

280

20

280

5

280

5

280

5

280

5

240

20

240

20

240

20

240

20

240

5

240

5

240

5

240

5

°C

min

230

120

230

60

200

120

200

60

230

120

230

60

200

120

200

60

230

120

230

60

200

120

200

60

230

120

230

60

200

120

200

60

AV

(High/low)

0.14 0.09 0.09 0.04 0.08 0.19 0.53 1.98 0.08 0.11 0.17 0.54 0.11 0.89 1.09 2.86

AV

(Low/high)

0.21 0.45 0.5 0.3 0.18 0.6 0.53 0.65 0.09 0.62 1.19 1.47 0.07 0.53 0.74 2.31

Results of 2-step deodorization experiments

Most promising: Short deodorization at higher temperature first with following longer deodorization at lower temperature results in:

Remarkable lower contents of G-FE Comparable contents of 3-MCPD-FE Slightly lower peroxide values Slightly lower oxidative stability

But: Target conflict between low acid value and low content of 3-MCPD-FE/G-FE; but compromise is possible for low G-FE and constant acid value and 3-MCPD-FE

Short path distillation instead of deodorization

Feature of SPD Advantage

High vacuum (up to 0.001 mbar)

Decreased boiling point

Short heating time Reduced exposure to heat

Evaporation from a thin layer

No static pressure loss

More efficient heat transfer

Large surface area per volume element

Turbulent circulation No thermal gradient Permanent surface renewal

Short steam path Only one evaporation No gas veil

No stripping steam No waste water No hydrolytic splitting

Tight system Condensation of vapors

Less energy use

Results of short path distillation experiments

A B C D

A : Crude palm oil (CPO) B : degummed palm oil C : Palm oil after SPD D : Palm oil after conventional deodorization

Short path distillation (SPD) is a suitable method to produce a refined palm oil without 3-MCPD & Glycidyl esters.

Its chemical quality parameters are comparable with a conventionally refined palm oil.

SPD results in a red colored palm oil.

Sensory is negatively influenced.

Depending of crude oil quality a subsequent gentle deodorization at 160 - 180°C eliminates sensory disadvantages. This leads to slightly enhanced 3-MCPD esters.

How to refine

Choose / use suitable crude oil (low in DAG and ffa) Use chemical refining instead of physical refining Avoid low pH (e.g. by degumming with low acid amounts; neutralisation with calcium oxide) Use significant increased amounts of bleaching clay Use natural bleaching clays Use lower temperatures in deodorizing Use 2-step deodorizing (HTST followed by LTLT) Use short path distillation followed by gentle deodorization

Post bleaching by adsorbents

Strijowski et al., 2011

3-MCPD Esters Glycidyl Esters

3-MCPD Esters, RBD oil Glycidyl-Esters, RBD oil

3-MCPD esters are removed by carboxlmethyl cellulose or cation exchange resin under nitrogen (WO2011009841-A1)

Post refining methods

Post bleaching with different adsorbents followed by gentle deodorization Double bleaching / deodorization Use of short path distillation after deodorization

(WO2015/073359 – Cargill)

Treatment with ionic liquids

Advantages: • Ionic Liquid Treatment allows mild conditions and less resources in degumming, bleaching and

deodorization

• The treatment with ionic liquid is a reactive extraction of free fatty acids and similar to the chemical refining, but can be regenerated

• Lower energy demand and waste reduction have positive impact on planet category of sustainability

• Formation of potential carcinogenic by-products is reduced resulting in health benefits for the customer

Ionic Liquid Treatment

Refined Oil Separation

Regeneration FFA Stream

Crude Palm Oil Deodorisation

(reduced T) Bleaching

WO2016189115, WO2016189114, WO2015079262

IL treatment: oil quality

Reduction of phosphor and iron content is observed

Free fatty acids are almost completed removed after treatment step

13.3

7.2

Treated Palm Oil Crude Palm Oil

21.2

0.1

7.2

0.5

5.4

8.4 P [mg/kg]

SZ [mg KOH/kg]

POZ [meq O2/kg]

Fe [mg/kg]

IL treatment: 3-MCPD and Glycidyl esters

With the treated palm oil a reduction of deodorization temperature < 230 °C is possible

The amount of GE and 3-MCPD content is significantly reduced in comparison to conventional refined Palm oil (RBDPO)

0.9 1.1

2.1

Treated/refined PO Sample 3

2.6

0.8

Treated/refined PO Sample 1

Treated/refined PO Sample 2

2.5

2.0

1.5

3.7

0.8

1.6 1.5

RBDPO

6.1

3.3

5.1

3.6 GE FE [ppm]

3-MCPD FE [ppm]

P [mg/kg]

POZ [meq O2/kg]

Questions? www.ppm-magdeburg.de