CRYSTALLISATION BEHAVIOUR OF PALM OIL:

Crystal Size Distribution of Palm Oil and the

Ternary Blends during Isothermal Crystallization

using Focused Beam Reflectance Measurement

(FBRM) system

Zaliha Omar, Elina Hishamuddin and Norizzah Abd Rashid

Product Development & Advisory

Services Division, Malaysian Palm Oil Board, Malaysia

PRESENTATION OUTLINE

Introduction

Objectives

Materials and Methods

Results and Discussion

Conclusion

Acknowledgements

INTRODUCTION

Palm oil

Semi-solid at ambient temperature (25°C), consisting of low

and high melting triacylglycerols (TAGs).

Crystallized in either ' or mixture of (' + ) or

polymorphic forms depending on the crystallization

temperature.

Can be fractionated into liquid fraction (olein) and solid

fraction (stearin).

These unique characteristics make palm oil a versatile

ingredient in food and non-food products.

The crystallization process is a controlled cooling

process from a higher to lower temperature to

obtain the desired:-

o crystal number, size distribution, polymorph, TAGs,

FAC to form different functional of palm fractions

o textural properties and physical characteristics of

food products.

Crystallisation process of oils and fats:-

super cooling from melt

Nucleation

( ) Monotropic manner

Crystal growth

Aggregation of crystal

Crystal network

CRYSTALLISATION PR

OCESS

Palm oil slurry after

crystallization process

Filtration

Olein (liquid 55-65%)

SMP (low) 19.4-23.5ºC

IV 63

Soft stearin

Palm-mid fraction (semi-solid 25-30%)

SMP 45-48ºC

IV 33

Hard stearin

(Solid 10-15%)

SMP 56-58ºC

IV 10

Factors influencing the Macroscopic properties of

fat crystal networks

Macroscopic Properties

(end products), eg. Texture,

rheology

Microstructure

(Sizes)

Polymorphism

α, β‘, β

Polyptism

Lipid Composition

(TAG, FAC))

Processing conditions

• Temperature

• Agitation

• Cooling rate

• Cooling profile etc.

(Marangoni, 2001)

Recent study

FBRM capable of assessing changes in particle size

of palm oil crystals and in detecting multiple

crystallization events in palm oil system

(Hishamuddin et al., 2011).

FBRM is becoming a more popular technique to

measure particle size on-line in different applications.

The technique gives information on online

monitoring of particle numbers and size distributions

during the crystallisation process.

OBJECTIVES

To measure the total particle counts and chord length

distribution (CLD) of Palm Oil and ternary blends

using FBRM under isothermal crystallisation.

To determine the effects of blending palm oil, palm

stearin, palm olein and soya bean oil on the particle

size, triacylglycerol, polymorphic form and fatty acid

composition.

Materials

Palm oil (PO, IV 53.5), palm stearin (PS, IV38), palm olein

(POo, IV59) - Jomalina Sdn. Bhd. Port Klang, M’sia.

Soybean oil (SBO) from local supermarket.

Blends preparation:-

PO:PS: POo and PO:PS:SBO at weight ratio

of 50, 30 and 20 (w/w)

Methods

Crystal size distribution (CLD) under isothermal

crystallisation process - FBRM

Triacylglycerol (TAG) profiles – HPLC

Fatty acid composition (FAC) – GC

Microscopic observation – PLM

Polymorphic form – X-ray diffractometer

Isothermal crystallisation of

palm oil and ternary blends

from melt was monitored

online using a Lasentec

FBRM probe inserted into

the stirred reactor (100rpm).

The crystallisation were

carried out at 28, 30 and

32°C

continue

Schematic diagram of FBRM probe

Total particle counts of Palm Oil during

isothermal crystallisation pocess

RESULTS AND DISCUSSION

Nucleation

induction time

Total particle counts of

PO:PS:POo(50:30:20) blend

Total particle counts of PO:PS:SBO(50:30:20) blend

continue

RBDPO [A] PO:PS:POo(50:30:20)[B

]

PO:PS:SBO(50:30:20

)

PO

21µm and 61µm

PO:PS:POo(50:30:20)

51µm

PO:PS:SBO (50:30:20)

65 µm

The chord length distributions (CLD) -

isothermal crystallisation at 30°c

Sample C12:0 C14:0 C16:0 C18:0 C18:1 C18:2 C18:3 C20:0

PO 0.2 1.1 45.2 4.1 38.8 9.9 0.2 0.3

PS 0.2 1.4 59.3 4.7 27.4 6.3 0.1 0.3

POo 0.2 1.0 39.7 4.0 44.0 10.1 0.3 0.4

SBO - - 10.9 4.4 22.1 53.8 7.5 0.3

PO:PS:SBO

(50:30:20)

0.2 1.0 43.9 4.6

32.4 17.3 1.4 0.3

PO:PS:POo

(50:30:20)

0.3 1.1 45.4 4.7 37.6 9.9 0.2 0.4

FATTY ACID COMPOSITION (%)

• PO and PS – rich in palmitic and oleic acids

• SBO – contains mainly oleic and linoleic acids

• Both blends – high amounts of palmitic and oleic acids

TRIACYLGLYCEROL COMPOSITION (%)

Sample OLL PLL OOL/

OLO

PLO PLP OOO POO POP PPP SOO POS PPS

PO

(Palm oil)

0.36 2.20 1.68 9.46 9.44 4.90 24.30 30.6 5.07 2.51 4.96 0.91

PS

(Palm stearin)

0.22 1.13 0.79 4.88 6.51 3.84 12.61 27.99 22.18 1.44 5.13 4.45

POo

(Palm olein)

- 0.5 1.80 11.8 10.4 4.1 36.21 32.1 0.60 2.60 5.5 -

SBO

(soyabean oil)

16.0 14.0 7.30 11.11 2.10 2.60 4.71 0.60 0.31 0.90 0.31 -

PO:PS:SBO

(50:30:20)

4.2 5.2 3.6 8.8 7.6 4.1 15.7 23.0 11.1 1.9 3.9 2.0

PO:PS:POo

(50:30:20)

0.4 2.4 1.4 9.5 9.5 4.6 23.4 27.9 10.0 2.7 5.0 2.0

P=Palmitic acid, S=stearic acid, L=Linoleic acid, O=Oleic acid.

Samples Polymorphic form

PO β´

POo β´

SBO β

PO:PS:SBO (50:30:20) (β´+ β)

PO:PS:POo (50:30:20) β´

POLYMORPHIC FORM

X-ray relative intensity (short spacings):-

’ at 4.2 and 3.8Å and

at 4.6Å

The difference in the induction times and the CLD of Palm Oil

and the ternary blends were possibly due to the chemical

characteristics such as the triacylglycerol composition and fatty

acid profile of each type of oil in the blends.

The faster nucleation rate could be due to the higher content of

high melting TAGs of the blends such as PPP and PPS as

compared to Palm Oil which also caused the blends slurry to be

more denser.

The chord length distribution (CLD) of PO at the end of

crystallisation process were shorter than ternary blend

containing SBO but longer than blend with palm olein .

Palm stearin, Palm olein and soya bean oil altered the crystal

size distribution of Palm Oil.

CONCLUSION

1. Braatz, R.D. (2002) “Advanced control of crystallization processes”

Annual Reviews in Control 26:87-99.

2. Hishamuddin, E., Andrew, Stapley, G.F., and Zoltan K.N. (2011).

“Application of laser backscattering for monitoring of palm oil

crystallisation from melt” Journal of Crystal Growth 335:172-180.

3. Simmons, M.J.H., Langston, P.A. and Burbidge, A.S. (1999). “ Particle

and droplet size analysis from chord distributions” Journal of Powder

Technology 102:75-83.

4. Stéphanie, B. and Ronald W. R. Rousseau (2006). “Utilization of Focused

Beam Reflectance Measurement in the Control of Crystal Size

Distribution in a Batch Cooled Crystallizer” Chem. Eng. Technol. 29(2) pp

206-211.

REFERENCES

ACKNOWLEDGEMENTS

Special thanks to:-

The Director General of Malaysian Palm oil

Board (MPOB)

The Head of Faculty of Applied Sciences of

Universiti Teknologi MARA Shah Alam, Malaysia

for permission to present this paper

All the Physics and Chemistry Laboratory staff of

MPOB for their assistance.