universiti putra malaysia production of palm-based diacylglycerol olein and stearin through dry...
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UNIVERSITI PUTRA MALAYSIA
RAZAM ABD LATIP
FBSB 2012 37
PRODUCTION OF PALM-BASED DIACYLGLYCEROL OLEIN AND STEARIN THROUGH DRY FRACTIONATION OF PALM-BASED DIACYLGLYCEROL FAT
AND ITS APPLICATIONS AS COOKING OIL AND BAKERY SHORTENING
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PRODUCTION OF PALM-BASED DIACYLGLYCEROL OLEIN AND
STEARIN THROUGH DRY FRACTIONATION OF PALM-BASED
DIACYLGLYCEROL FAT AND ITS APPLICATIONS AS COOKING OIL
AND BAKERY SHORTENING
By
RAZAM ABD LATIP
Thesis Submitted to the School of Graduate Studies, Universiti Putra Malaysia,
in Fulfilment of the Requirement for the Degree of Doctor of Philosophy
April 2012
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Abstract of thesis presented to the Senate of Universiti Putra Malaysia in fulfilment
of the requirement for the degree of Doctor of Philosophy
PRODUCTION OF PALM-BASED DIACYLGLYCEROL OLEIN AND
STEARIN THROUGH DRY FRACTIONATION OF PALM-BASED
DIACYLGLYCEROL FAT AND ITS APPLICATIONS AS COOKING OIL
AND BAKERY SHORTENING
By
RAZAM ABD LATIP
April 2012
Chairman : Professor Lai Oi Ming, PhD
Faculty : Faculty of Biotechnology and Biomolecular Sciences
This work was aimed at developing a novel fractional crystallisation process of
palm-based diacylglycerol (PDAG) fat for production of palm-based diacylglycerol
olein (PDAGL) and palm-based diacylglycerol stearin (PDAGS) for applications as
cooking oil and bakery shortening. In the first part of this work, the effect of
crystallisation temperature (Ct), cooling rate (Cr) and agitation speed (As) on
physical and chemical properties of PDAGL and PDAGS were studied. It was noted
that as Cr increased, the amount of palmitic acid, C16:0 and oleic acid, C18:1 in
PDAGL increased (from 35.0 to 37.2%) and decreased (from 47.1 to 45.3%),
respectively, resulting in decrease in iodine value (IV) (from 58.8 to 52.3). Similar
trend was observed when Ct is increased, the amount of C16:0 increased from 33.5
to 38.7% and C18:1 decreased from 49.1 to 44.6%. Fast cooling produced PDAGS
with lower amount of saturated fatty acid C16 and hence, contributed to higher IV.
There is no correlation between physical and chemical properties of PDAGL and
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PDAGS with different As. Crystallisation process parameters namely Cr, Ct and As
were optimized using dual response surface methodology (RSM) in lab scale. The
optimal crystallisation process parameters were 1.0 C/min of Cr, 46 rpm of As and
37 C of Ct which yielded approximately 70 wt % of PDAGL with 58 IV. The
optimal crystallisation process parameters can be further scaled-up to a 50 kg
crystalliser for production of PDAGL with similar IV and percentage yield.
The oxidative stability of PDAG oil and its olein fraction were investigated at 120
C by the rancimat method with and without addition of antioxidants. Heat stability
test was conducted at 90 C for 5 days. Compared with TAG-based oils, the PDAG-
based oil displayed lower oxidative stability due to lower content of tocopherols.
The oxidative stability of PDAGL improved with addition of 1000 ppm tocopherols,
1000 ppm citric acid, 200 ppm tertiary butyl hydroquinone (TBHQ) and mixture of
100 ppm BHT and 100 ppm BHA. Among all antioxidants, natural antioxidant,
tocopherol and synthethic antioxidant, TBHQ showed highest oxidative stability
improvement to the oil. The induction period (IP) of PDAGL increased from 10.26
0.28 to 13.58 0.43 and 19.72 0.36 h with addition of 1000 ppm tocopherol and
200 ppm TBHQ, respectively. The stability of palm olein (POL), PDAGL without
antioxidant and with 1000 ppm tocopherol (PDAGL(T)) and 200 ppm TBHQ
(PDAGL(Q)) under deep-frying conditions were investigated. PDAGL exhibited
better IP than POL. However, the free fatty acid (FFA) increased 3 times faster in
PDAGL compared to POL. The rate of FFA formation in PDAGL was 0.7 times
lower when antioxidants were added. However, no significant difference (P>0.05) in
FFA content was observed in PDAGL and PDAGL(Q). The initial IP of PDAGL
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(9.95 + 0.04 h) was increased upon addition of tocopherol (14.55+0.05 h) and TBHQ
(17.83 + 0.04 h). PDAGL(T) showed slower reduction in the IP throughout frying
process as compared to PDAGL(Q). However, additions of antioxidants to PDAGL
showed no significant effect (P>0.05) in polymerized-glyceride (PG) and anisidine
value (AV) produced throughout the frying due to oxidization of the antioxidants
upon heating, thus decreasing their antioxidant activities. It can be concluded that
PDAGL is suitable as cooking oil but not for industrial frying oil.
The physicochemical properties including phase, melting and crystallisation
behavior of shortening systems produced from PDAGS with palm-mid fraction
(PMF), POL and sunflower oil (SFO) were studied. The results showed that
PDAGS and PMF were hard fats while SFO was a softer oil than POL. Due to sharp
melting points of PMF, the SFC profile of PDAGS/PMF was able to achieve the
desired level of solid fat especially at body temperature for food application. The
binary mixtures of PDAGS/SFO had very low SFC at temperature below 35oC as
compared to PDAGS/POL. The melting profiles of PDAGS/PMF, PDAGS/POL and
PDAGS/SFO had completely different low melting fraction (LMF) and medium
melting fraction (MMF) but almost similar high melting fraction (HMF).
Thermodynamic analysis of liquidus line showed that all binary mixtures of
PDAGS/ PMF, PDAGS/POL and PDAGS/SFO had ideal mixing behavior where the
calculated liquidus line reproduced well with the experimental points in phase
diagram. The iso-solid diagram constructed showed that no eutectic behavior existed
in all binary mixtures. However, the iso-solid lines of PDAGS/POL lacked structural
complementary between high and low percentage of SFC line, while PDAGS/SFO
not well constructed at high percentage of SFC line. The results from X-Ray
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Diffractometer (XRD) analysis showed that both binary mixtures of PDAGS/PMF
and PDAGS/SFO were crystallized in β’+β polymorphs at XPDAGS = 0.4 to XPDAGS =
0.5, while all the binary mixtures of PDAGS/POL were crystallized in β
polymorphs. Overall analyses results gave indication that PDAGS and PMF blend
was the most suitable fat blend to be used as bakery shortening.
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Abstrak tesis yang dikemukakan kepada Senat Universiti Putra Malaysia sebagai
memenuhi keperluan untuk ijazah Doktor Falsafah
PENGHASILAN OLEIN DAN STEARIN DIASILGLISERIDA MINYAK
SAWIT MELALUI PROSES FRAKSINASI KERING LEMAK
DIASILGLISERIDA MINYAK SAWIT BAGI APLIKASI SEBAGAI
MINYAK MASAK DAN LELEMAK BAKERI
Oleh
RAZAM ABD LATIP
April 2012
Pengerusi : Profesor Lai Oi Ming, PhD
Fakulti : Fakulti Bioteknologi dan Sains Biomolekul
Kajian ini bertujuan untuk menghasilkan satu proses baru fraksinasi untuk lelemak
diasilgliserida minyak sawit (PDAG) bagi penghasilan olein diasilgliserida minyak
sawit (PDAGL) dan sterin diasilgliserida minyak sawit (PDAGS) untuk
diaplikasikan sebagai minyak masak dan lelemak bakeri. Pada peringkat awal
kajian ini, pengaruh suhu pengkristalan (Ct), kadar penyejukan (Cr) dan kelajuan
kitaran (As) terhadap sifat fizikal dan kimia PDAG dan PDAGS telah dikaji.
Peningkatan Cr, menyebabkan peningkatan jumlah asid palmitik, C16 (dari 35.0
kepada 37.2%) dan penurunan (dari 47.1 kepada 45.3%) jumlah asid oleik, C18:1 di
dalam PDAGL menyebabkan nilai iodin (IV) yang lebih rendah. Keadaan yang
serupa dapat diperhatikan apabila Ct meningkat, di mana jumlah C16 meningkat
daripada 33.5% kepada 38.7% dan C18:1 menurun daripada 49.1% kepada 4.6%.
Penyejukan cepat menghasilkan PDAGS dengan jumlah lemak tepu, C16 yang lebih
rendah, maka menghasilkan IV yang tinggi. Tiada korelasi antara sifat fizikal dan
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kimia PDAGL dan PDAGS pada As yang berbeza. Parameter proses pengkristalan
seperti Cr, Ct dan As telah dioptimumkan melalui Kaedah Tindakbalas Permukaan
(RSM) dalam skala makmal. Parameter optima bagi proses pengkristalan PDAG
adalah 1.0 oC/min bagi Cr, 46 rpm bagi As dan 37
oC bagi Ct yang mana
menghasilkan lebih kurang 70% daripada berat PDAGL dengan IV 58. Parameter
untuk proses pengkristalan yang optimum boleh digunakan pada skala yang lebih
besar sehingga pengkristal 50 kg untuk menghasilkan PDAGL dengan IV dan
peratusan penghasilan yang sama.
Kestabilan oksidatif minyak PDAG dan PDAGL tanpa dan dengan penambahan
antioksida telah dijalankan pada suhu 120oC menggunakan kaedah ransimat.
Manakala ujian kestabilan haba telah dijalankan pada suhu 90oC selama 5 hari.
Berbanding dengan minyak berasaskan TAG, minyak berasaskan PDAG
menunjukkan kestabilan oksidatif yang lebih rendah disebabkan kandungan
tokoferol yang rendah. Kestabilan oksidatif PDAGL meningkat dengan
penambahan 1000 ppm tokoferol, 1000 ppm citric asid, 200 ppm tertiari butil
hidrokuinon (TBHQ) dan campuran dari 100 ppm BHT dan 100 ppm BHA. Di
antara semua antioksida, antioksida semulajadi tokoferol dan antioksida sintetik
TBHQ menunjukkan peningkatan kestabilan oksidatif tertinggi bagi minyak yang
diuji. Tempoh induksi (IP) untuk PDAGL meningkat dari 10.26+0.28 ke
13.58+0.43 dan 19.72+0.36 h dengan penambahan 1000 ppm tokoferol dan 200 ppm
TBHQ. Kestabilan POL, PDAGL tanpa antioksida dan PDAGL dengan 1000 ppm
tokoferol (PDAGL(T)) dan 200 ppm TBHQ (PDAGL(Q)) telah dikaji di bawah
keadaan pengorengan penuh. PDAGL menunjukkan IP yang lebih baik dari POL.
Walaubagaimanapun, FFA telah meningkat 3 kali lebih cepat dalam PDAGL
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berbanding POL. Kadar pembentukan FFA dalam PDAGL adalah 0.7 kali lebih
rendah apabila ditambah antioksida. Namun begitu tiada perbezaan yang ketara
(P>0.05) didapati bagi kandungan FFA bagi PDAGL dan PDAGL(Q). IP awal
untuk PDAGL (9,95 + 0,04 h) telah meningkat ketika penambahan tokoferol (14,55
0.05 h) dan TBHQ (17,83 0,04 h). PDAGL(T) menunjukkan penurunan yang
perlahan dalam IP semasa proses pengorengan berbanding dengan PDAGL(Q).
Namun, penambahan antioksida pada PDAGL tidak menunjukkan kesan ketara
(P>0.05) pada PG dan AV yang dihasilkan semasa pengorengan berikutan
pengoksidaan keatas antioksida semasa pemanasan sehingga menyebabkan
penurunan aktiviti antioksida mereka. Ianya boleh disimpulkan bahawa PDAGL
adalah sesuai sebagai minyak masak tetapi tidak sesuai sebagai minyak goreng
berskala industri.
Sifat fisiokimia termasuk fasa, peleburan dan penghabluran sistem lelemak yang
dihasilkan daripada PDAGS dicampur dengan Minyak Sawit Pertengahan (PMF),
Minyak Olein Sawit (POL) dan Minyak Bunga Matahari (SFO) telah dikaji. Hasil
kajian menunjukkan PDAGS dan PMF merupakan lemak keras manakala SFO
merupakan minyak yang lebih lembut berbanding POL. Disebabkan oleh takat lebur
PMF yang tajam, profil SFC bagi PDAGS/PMF boleh mencapai tahap lemak pepejal
yang diingini terutamanya pada suhu badan bagi aplikasi makanan. Campuran binari
PDAGS/SFO mempunyai kandungan SFC yang sangat rendah pada suhu di bawah
35 ºC jika dibandingkan dengan PDAGS/POL. Profil peleburan PDAGS/PMF,
PDAGS/POL dan PDAGS/SFO mempunyai pecahan peleburan rendah (LMF) dan
pecahan peleburan pertengahan (MMF) yang berbeza sepenuhnya tetapi mempunyai
hampir sama pecahan peleburan tinggi (HMF). Analisis termodinamik garisan cecair
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menunjukkan kesemua campuran binari PDAGS/PMF, PDAGS/POL dan
PDAGS/SFO mempunyai perilaku campuran ideal dimana kiraan garisan cecair
dihasilkan semula lebih baik, dengan takat eksperimen dalam rajah fasa. Rajah iso-
pepejal yang dihasilkan menunjukkan tiada perilaku eutektik wujud dalam campuran
binari. Walaubagaimanapun, garisan iso-pepejal PDAGS/POL kekurangan struktur
yang saling melengkapi antara peratus garisan SFC tinggi dan rendah, sementara
garisan iso-pepejal PDAGS/SFO tidak dihasilkan dengan baik pada peratus garisan
SFC yang tinggi. Hasil daripada analisa XRD menunjukkan bahawa kedua-dua
campuran PDAGS/PMF dan PDAGS/SFO adalah penghabluran dalam
pempolimorfan ß’ + ß pada XPDAGS = 0.4 kepada XPDAGS =0.5, sementara kesemua
campuran binari PDAGS/POL adalah penghabluran dalam pempolimorfan ß. Hasil
analisa keseluruhan menunjukkan campuran PDAGS dan PMF adalah campuran
yang paling sesuai untuk digunakan dalam lelemak bakeri.
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ACKNOWLEDGEMENTS
With great thanks to Almighty Allah S.W.T and His mercy for giving me life and
the opportunity to write this thesis as required.
I would like to take this opportunity to express my most sincere appreciation and
deepest gratitude to Prof. Dr Lai Oi Ming of Faculty of Biotechnology and
Biomolecular Sciences. Without her valuable guidance, advice, suggestions and
constructive criticisms, I would not have been able to present my work and in the
preparation of this thesis.
I offer my sincere thanks to other members of the Assoc. Prof. Dr. Tan Chin Ping of
Faculty of Food Science and Technology, Dr. Kamariah Long of MARDI for their
supervision, support and comments.
Special thanks and appreciation to my friends and staff of Sime Darby Research
Sdn. Bhd. for their assistance in preparing this thesis. I would also like to
acknowledge Sime Darby Research Sdn. Bhd. for approving my PhD studies and for
the laboratory facilities made available in Sime Darby Jomalina Sdn. Bhd.
I also owe my special thanks to my beloved wife Aziah Lajis for her inspiration,
moral encouragement, support, patience and sacrifices which had helped me in my
undertakings and completing this research study.
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This thesis was submitted to the Senate of Universiti Putra Malaysia and has been
accepted as fulfillment of the requirement for the degree of Doctor of Philosophy.
The members of the Supervisory Committee were as follows:
Lai Oi Ming, PhD
Professor,
Faculty of Biotechnology and Biomolecular Sciences
Universiti Putra Malaysia
(Chairman)
Tan Chin Ping, PhD
Associate Professor,
Faculty of Food Science and Technology
Universiti Putra Malaysia
(Member)
Kamariah Long, PhD
Deputy Director
Bio-Processing Programme,
Biotechnology Research Centre,
MARDI Head Quarters
(Member)
…………………………………………
BUJANG BIN KIM HUAT, PhD
Professor and Deputy Dean,
School of Graduate Studies
Universiti Putra Malaysia
Date :
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DECLARATION
I declare that the thesis is my original work except for quotations and citations,
which have been duly acknowledged. I also declare that it has not been previously
and it is not currently, submitted for any other degree at Universiti Putra Malaysia or
other institutions.
…………………………………………
RAZAM ABD LATIP
Date : 20 April 2012
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TABLE OF CONTENTS
Page
ABSTRACT ii
ABSTRAK vi
ACKNOWLEDGEMENTS x
APPROVAL xi
DECLARATION xiii
LIST OF TABLES xix
LIST OF FIGURES
LIST OF PHOTOGRAPHS
xxi
xxiv
LIST OF ABBREVIATIONS xxv
CHAPTER
1 INTRODUCTION 1
2 LITERATURE REVIEW 6
2.1 Obesity 6
2.2 Diacylglycerols 7
2.2.1 Introduction 7
2.2.2 Metabolic process of DAG 9
2.2.3 Health benefits of DAG 10
2.2.4 Productions of DAG 12
2.2.5 General application of DAG 14
2.3 Fractionation 15
2.3.1 Introduction to fractionation 15
2.3.2 Crystallisation 17
2.3.3 Separation 24
2.3.4 Type of fractionation
2.3.5 Parameters Affecting Crystallisation
26
29
2.4 Food- grade Antioxidants 35
2.4.1 Introduction 35
2.4.2 Butylated Hydroxytoluene (BHT) 37
2.4.3 Tertiary Butylhydroquinone (TBHQ) 37
2.4.4 Tocopherols 38
2.4.5 Evaluation of Antioxidants Effectiveness via
Accelerated Oxidative Stability Methods
38
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2.5 Frying Process 41
2.5.1 Introduction to Frying 41
2.5.2 Safety Aspects and Oil Performance Indicators 44
2.5.3 Rapid Method for Assessing Frying Oil Abuse 45
2.6 Shortening 48
2.6.1 Introduction to shortening 48
2.6.2 Bakery shortening 49
2.6.3 Production of shortenings 51
2.6.4 Phycisochemical characteristics of shortenings 52
2.7 Conclusions 54
3 EFFECT OF CRYSTALLISATION TEMPERATURE,
COOLING RATE AND AGITATION SPEED ON THE
PHYSICOCHEMICAL PROPERTIES OF DRY
FRACTIONATED PDAG FRACTIONS
56
3.1 Introduction 56
3.2 Material and Methods 57
3.2.1 Materials 57
3.2.2 Methods 58
3.2.2.1 Fractional crystallisation 58
3.2.2.2 Iodine Value (IV) determination 61
3.2.2.3 Fatty Acid Composition (FAC) analysis 61
3.2.2.4 Analysis of acylglycerol composition 61
3.2.2.5 Slip Melting Point (SMP) 62
3.2.2.6 Solid Fat Content (SFC) 62
3.2.2.7 Thermal behavior by Differential Scanning
Calorimetry (DSC)
63
3.2.2.8 Statistical Analysis 63
3.3 Results and Discussion 63
3.3.1 IV, SFC and Percentage of Yield 63
3.3.2 Solid Fat Content 71
3.3.3 Slip melting point 74
3.3.4 Thermal behavior properties 80
3.4 Conclusions 84
4 OPTIMISATION OF DRY FRACTIONATED PROCESS
PARAMETERS FOR PILOT-SCALE PRODUCTION
OF PDAG OLEIN
85
4.1 Introduction 85
4.2 Material and Methods 86
4.2.1 Materials 86
4.2.2 Methods 87
4.2.2.1 Experimental Design 87
4.2.2.2 Fractional Crystallisation 88
4.2.2.3 Pilot Plant Scale Fractional Crystallisation 89
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4.2.2.4 Iodine Value (IV) 90
4.3 Results and Discussion 91
4.3.1 Model fitting for IV of PDAGL 91
4.3.2 Model fitting for percentage yield of PDAGL 94
4.3.3 Comparison of Main Effects of Variables on IV
and Percentage Yields
96
4.3.4 Comparison of Response Contour Plots for IV and
Percentage Yields
98
4.3.5 Optimisation of Fractional Crystallisation Process 104
4.3.6 Scaling up of fractional crystallisation 105
4.4 Conclusions 106
5 OXIDATIVE, HEAT STABILITY TEST AND FRYING
PERFORMANCE OF PALM-BASED
DIACYLGLYCEROL OIL AND ITS OLEIN
FRACTION
107
5.1 Introduction 107
5.2 Material and Methods
5.2.1 Materials 110
5.2.2 Methods 110
5.2.2.1 Sample preparation 110
5.2.2.2 Analysis of acylglycerol composition 111
5.2.2.3 Fatty acid composition (FAC) 111
5.2.2.4 Iodine value (IV) 111
5.2.2.5 Smoke point 111
5.2.2.6 Rancimat test 111
5.2.2.7 Heat stability test 112
5.2.2.8 Polymerized-glyceride (PG) test 112
5.2.2.9 Frying experiment 113
5.2.2.10Statistical analysis 113
5.3 Results and Discussion 114
5.3.1 Acylglycerol Composition, FAC, Tocopherol
Content and Smoke Point
114
5.3.2 Oxidative stability 116
5.3.3 Heat stability 121
5.3.4 Frying Performance 124
5.3.4.1 Fresh oil quality 124
5.3.4.2 Physicochemical properties of oil during frying 125
5.3.4.2.1 Oxidative stability and colour 125
5.3.4.2.2 Free fatty acid (FFA) and Moisture Content 127
5.3.4.2.3 Anisidine Value (AV) 129
5.3.4.2.4 Polymerized glyceride (PG) 130
5.4 Conclusions 131
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6 PHYSICOCHEMICAL PROPERTIES AND
CRYSTALLISATION BEHAVIOUR OF BAKERY
SHORTENING PRODUCED FROM STEARIN
FRACTION OF PALM-BASED DIACYLGLYCEROL
BLENDED WITH VARIOUS VEGETABLE OILS
133
6.1 Introduction 133
6.2 Material and Methods 135
6.2.1 Materials 135
6.2.2 Methods 135
6.2.2.1 Sample preparation 135
6.2.2.2 Fatty Acid Composition (FAC) analysis 136
6.2.2.3 Slip melting point (SMP) 136
6.2.2.4 Solid fat content (SFC) 136
6.2.2.5 Thermal behavior differential scanning
calorimetry (DSC)
136
6.2.2.6 X-Ray Diffractometer (XRD) 136
6.2.2.7 Statistical analysis 137
6.3 Results and Discussion
6.3.1 FAC of PDAGS, PMF, SFO and their binary
mixtures
137
6.3.2 SMP of PDAGS, PMF, POL, SFO and their
binary mixtures
139
6.3.3 SFC of PDAGS, PMF, POL, SFO and their binary
mixtures 139
6.3.4 Iso-solid Diagram of PDAGS/PMF, PDAGS/POL
and PDAGS/SFO
142
6.3.5 DSC results of PDAGS/PMF, PDAGS/POL and
PDAGS/SFO
144
6.3.6 Phase Diagram of PDAGS/PMF, PDAGS/POL
and PDAGS/SFO
147
6.3.7 Thermodynamic analysis of the liquidus line in the
phase diagram of PDAGS/PMF, PDAGS/POL and
PDAGS/SFO
150
6.3.8 Subcell Packing and Polymorphs of PDAGS, PMF
and PDAGS/PMF; PDAGS, POL and
PDAGS/POL; PDAGS, SFO and PDAGS/SFO
151
6.4 Conclusions 152
7 SUMMARY, GENERAL CONCLUSIONS AND
RECOMMENDATIONS FOR FUTURE RESEARCH
154
7.1 Summary 154
7.2 General Conclusions and Recommendation for Future
Research
157
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8 BIBLIOGRAPHY 158
9 BIODATA OF STUDENT 182