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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]