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.