Developments in Edible Oil Refining for the Production of ...aocs.files.cms-plus.com/ResourcesPDF/refining_desmet_ballestra.pdf · 1 Developments in Edible Oil Refining for the Production

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Developments in Edible Oil Refining for

the Production of High Quality Food Oils

Wim De GreytDesmet Ballestra Group, Zaventem, Belgium

101st AOCS Annual Meeting May 16-19, 2010

Phoenix, Arizona


Phoenix, Arizona,USA

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Palm Soybean Rapeseed Sunflower Palm Kernel Cottonseed Coconut Olive Corn Others

WORLD VEGETABLE OIL PRODUCTION - 2008

Total : 140 Mio Ton

9%

VEGETABLE OILS : GENERAL COMPOSITION

Acylglycerols (92-95%)-Mainly Triacylglycerols-Some Di- and Monoacylglycerols

FFA (0.3-5%)

Phospholipids (<3%)-Hydratable PL-Non-hydratable PL

Minor components (0.3-2%)- Tocopherols, Sterols, Pigments,…- Contaminants, Impurities,….



VEGETABLE OILS : MINOR COMPONENTS

MINORMINORCOMPONENTSCOMPONENTS

Valuable Minor Components

- Desired in the refined oil- Good nutritional properties- To be retained during refining

Tocopherols, Sterols,….

Side Reaction Products

Trans FA, polymers, (3-MCPD esters),…

- Formed during refining- Bad nutritional properties- Unwanted

Contaminants

Pesticides, PAH, Dioxins,…

- Present in crude oils- Carcinogenic/Toxic- To be removed during refining



OILOILQUALITYQUALITY

Organoleptic quality /stability Nutritional Quality

-Bland taste, no odor-Light color (brilliant) -High thermal stability-High oxidative stability-Long shelf life

- High tocopherol content- No trans FA - No contaminants- No side-reaction products-(Fatty acid composition)

‘Standard’Quality Parameters

‘New’Quality Parameters

REFINED OIL QUALITY PARAMETERS

Optimized Edible Oil Processing required to meet new oil Quality Parameters


Phoenix, Arizona

EFFICIENCY

QUALITYSUSTAINABILITY

REFINING REFINING PROCESS PROCESS

CONDITIONSCONDITIONS

REFINERS CHALLENGE



Crude Oil

Water degumming

Alkali Neutralisation

Deodorization

Fully Refined Oil

Soapstock

Spentbleaching earth

Deodorizer Distillate

WDG Oil

Acid degumming

Bleaching

Physical deacidificationDeodorization

Bleaching

Acid Gums

Gums

Chemical refining Physical refining

EDIBLE OIL REFINING : PROCESS OPTIONS



• Deodorization/Steam Stripping

– Pesticides (herbicides,insecticides,fungicides,….)– Light PAH (e.g. from coconut oil)– Ortho-PCB (non dioxin-like PCB)

• Adsorption on specific adsorbens (active carbon)

– Heavy Polycyclic Aromatic Hydrocarbons (PAH)– Dioxins and furans from Fish Oils– Dioxin-like PCB (non-ortho PCB)

CONTAMINANT REMOVAL DURING OIL PROCESSING



Vacuum unit

Spent bleach earth

Bleachingearth

Degummed

acid

bleacher

Leaf filters

Bleached oil

Polish filters

Spargesteam

... ..

..

...

To deodorisation

Spent bleach earth

Pre filtrationfinal filtration

cleaning

Active carbon

Spent carbon

Filter press

Silica

oil

..

... .. ..

.

12

Silica + Prebleaching

3

bleaching

4

Removal of contaminants

Combiclean process meets refiners challenge



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200°C 210°C 220°C 230°C 240°C 250°C 260°C 270°C

250°C

270°C

230°C

%TF

A%

TFA

Time (minutes)

260°C

TFA max. 1.0%

TFA formation during soybean oil deodorization

REDUCING HEAT LOAD AND KEEPING STRIPPING EFFICIENCY HIGH



Scrubber

Stripper

DeodorizerDeaerator

Single orDual Temp

Lowpressure

short pack

•Cooling Water

•881B Final Oil Cooler

•881A Oil/Oil Heat Exchanger•808 Splash Oil Recovery

•810 Oil Deaeration

•P801

•P880A2

•880A2

•822

•880A1/822

•822TS

•823

•878AG Distillate Collection

•P878AG

•881AG Distillate Cooler

•P850/81AG

•Distillate Storage

•Steam

•841 Vacuum Plant

•Steam

•Steam

•Steam

•Steam

•Steam

•HP Heating Steam

•890 HP Steam generator

•to 841 vacuum plant

•to 841 vacuum plant

•816A Polishing Filters

•RB Oil Feed

LOWER HEAT LOAD – DUAL TEMPERATURE



IMPROVED VACUUM SYSTEMSCHILLED BAROMETRIC WATER ICE CONDENSING

* Lower pressure in the deodorizer - Lower motive steam consumption * Less odor emissions





NEW CHALLENGE : 3-MCPD / GLYCIDOL ESTERS

H2C

OCOR

C

O

CH2H2C

OH

C

O

CH2

H

Free glycidol Glycidol-ester

H

GLYCIDOL ESTERS

OH

OR

Cl

3-MCPD mono-(sn1) ester

OR

OH

Cl

OR’

OR

Cl

3-MCPD mono-(sn2) ester 3-MCPD di-ester

MCPD ESTERS

OCCURRENCE IN REFINED FOOD OILS

OIL N° Samples Average content3-MCPD ester

Max. level of 3-MCPD ester

Rapeseed Oil 31 0.3 mg/kg 1.5 mg/kg

Sunflower Oil 49 1.0 mg/kg 5.7 mg/kg

Corn Oil 15 2.8 mg/kg 7.0 mg/kg

Palm Oil 37 4.5 mg/kg 13 mg/kg

MCPD-ester content in various vegetable oils (source : FEDIOL)



* Reported data vary widely (due to applied method ?) * Most used (DGF) method not generally accepted * Mechanism of formation not fully understood * Very difficult to develop an efficient mitigation strategy

MECHANISM OF FORMATION : HYPOTHESIS

CH OH

H2C

H2C OH

O C

O

R2

CH OH

H2C

H2C OH2

O C

O

R2

H - H2O

Cl

CH OH

H2C

H2C Cl

O C

O

R2

CH

H2C

H2CO

Cl

C R2OO

MAG

3-MCPD mono-ester

Glycidol ester

MONOGLYCERIDES AS PRECURSOR

Nucleophilic substitution



Source : R. Verhé, Dept. Organic Chemistry, UGent, (2010)

CH

CH2

O C

CH2 OH

O C

O

O

R1

R2

CH

CH2

O C

CH2 OH2

O C

O

O

R1

R2

HCH

CH2

O C

CH2 Cl

O C

O

O

R1

R2

+ H2OCl

MECHANISM OF FORMATION : HYPOTHESISDIGLYCERIDES AS PRECURSOR

DAG 3-MCPD di-ester

CH O

H2C

H2C Cl

O COC CH3

O

CH

H2C

H2C Cl

O

O C

O

R

CH

H2C

H2CO

O C

O

R

270° C

∆

R > 240°C

DAG Glycidol-esters

OHOH



Nucleophilic substitution

Radicalar mechanismSource : R. Verhé, Dept. Organic Chemistry, UGent, (2010)

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Diglyceride content (%)

3-M

CD

P e

ster

con

tent

(mg/

kg)

Palm Oil, deodorized at 260°C

012345678

0 0,2 0,4 0,6 0,8 1 1,2Monoglyceride-content (%)

MC

PD

est

er c

onte

nt (m

g/kg

)

Palm Oil, deodorized at 260°C

Source :Karel Hrncirik (Unilever,2009) and Bertrand Matthaus (MRI, 2009)

Mono- and diglycerides and 3-MCPD ester formation

* Low DAG content will result in low 3-MCPD/glycidol-ester content

* If DAG > 4%, then 3-MCPD/glycidol ester content is mostly > 5 ppm* No apparent correlation between MAG and 3-MCPD/glycidol ester formation


Phoenix, Arizona

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150 200 250 300

Temperature (°C)

3-M

CPD

est

er (p

pm)

05

101520253035404550

150 200 250 300

Temperature (°C)

Gly

cido

l est

ers

(ppm

)

EFFECT OF TEMPERATURE

♦ : 1 hr; ■■ : 2 hr ▲▲: 4 hr ♦ : 1 hr; ■■ : 2 hr ▲▲: 4 hr

3-MCPD esters Glycidol esters

Temperature more important parameter than timeAt t > 240°C, mainly glycidol-esters are formed (exponential increase)

Formation of 3-MCPD esters is relatively independent of temperature (2-4 ppm)



Source : Bertrand Matthaus (MRI, 2009)

MITIGATION STRATEGY

Current statement of BfR (German Federal Institute for Risk Assessment)Alternative techniques have to be developed that guarantee the production of refined food oils with reduced or no 3-MCPD esters (and related compounds)

Today’s informal position of FEDIOLInformation so far obtained is insufficient to optimize the refining process for the mitigation (reduction/removal) of 3-MCPD esters and related compoundswhile maintaining the quality and food safety of the refined oil/fat



MITIGATION STRATEGY3-MCPD esters

-Require acidic conditions and presence of chloride-Can be formed during acid degumming and bleaching-Washing may remove chlorides from crude oil -Systematic monitoring of chlorides in all processing aids



Glycidol esters

-Can be formed from MAG via nucleophilic substitution (in absence of Cl-)-Formation from DAG possible via radicalair reaction at T > 240°C-Most likely to be formed during deodorization at high temp. (physical refining)-Dual temperature deodorization concept may give lower levels



CONCLUSIONVegetable Oil Refining can be optimized to meet new oil quality standards- Activated carbon process for removal of ‘heavy’ contaminants

- Optimized steam distillation/deodorization for removal of ‘light’ contaminants minimal trans formation

- Other refiners challenges (efficiency, environmental impact) are also met

3-MCPD and glycidol esters - Still some knowledge gaps makes good mitigation strategy difficult

- Need for a more reliable and accurate analytical methodology

- Better understanding of mechanisms of formation during food processingin general and oil refining in particular required

Documents

Developments in Edible Oil Refining for the Production of ...aocs.files.cms-plus.com/ResourcesPDF/refining_desmet_ballestra.pdf · 1 Developments in Edible Oil Refining for the Production