UNIVERSITI PUTRA MALAYSIA

BABAK HATAMI BAROOGH

FSTM 2012 16

CORRELATION OF ACRYLAMIDE WITH PRECURSORS AND COLOUR IN FROZEN PAR-FRIED FRENCH FRIES

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CORRELATION OF ACRYLAMIDE WITH PRECURSORS AND COLOUR IN FROZEN PAR-FRIED FRENCH FRIES

By

BABAK HATAMI BAROOGH

Thesis Submitted to the School of Graduate Studies, Universiti Putra Malaysia, in Fulfillment of the Requirements for the Master of Science

April 2012

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I DEDICATE THIS THESIS TO MY PARENTS AND ALL MY TEACHERS AND LECTURERS

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Abstract of thesis presented to the Senate of Universiti Putra Malaysia in fulfillment of the requirements for the degree of Master of Science

CORRELATION OF ACRYLAMIDE WITH PRECURSORS AND COLOUR IN

FROZEN PAR-FRIED FRENCH FRIES

By

BABAK HATAMI BAROOGH

April 2012

Chairman : Prof Jinap Selamat, PhD

Faculty : Food Science and Technology

The aim of this study was to verify the occurrence of acrylamide formation after final

frying and to study the correlation of acrylamide content with amino acids, reducing

sugars and moisture content in frozen French fries samples, also to investigate

acrylamide formation and reducing sugar content as main precursor in different

production date and production plant of frozen fried French fries samples. Acrylamide

analysis was based on gas chromatographic mass spectrometric technique (GC-MS) that

included extraction and derivatization before analysis. Amino acids and reducing sugars

determination has been done using high performance liquid chromatography (HPLC). It

was discovered that final frying generates 76.04-348.55 µg/kg of acrylamide in French

fries samples by wide range of reducing sugar content in the form of fructose and

glucose (0.11-1.30 and 0.096-1.294 mg/g, respectively) and fifteen free amino acids

(0.01-9.17 mg/g) that had been detected in frozen French fries sample before final

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frying. Although, asparagine content (2.76-9.17 mg/g) was higher among other free

amino acids, however; threonine and glutamine showed the higher correlation with

acrylamide content. In addition, among reducing sugars, there was a significant

correlation between glucose and acrylamide content and acrylamide and color

development (�a). It can be concluded correlation of acrylamide and precursors in

frozen par fried French fries samples is not same as fresh fried potatoes. In second part,

it has been investigated that there was not a significant difference between means of

acrylamide content and reducing sugars of different brand (P > 0.05) and was no

significant difference (P > 0.05) between reducing sugars and acrylamide content of two

harvest years (2008-2009), although; acrylamide content in 2009 was higher than 2008.

This part of study indicated that climate change from 2008 to 2009 has no significant

single effect on acrylamide content in this product. Acrylamide content formed after

frying frozen French fries sample of twelve month production within these two years

are significantly different (P < 0.05). The highest content of acrylamide (348.55µg/kg)

was found in samples produced in January that were significantly different among other

months. The lowest amount of acrylamide (76.04µg/kg) was found in samples produced

in September.

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Abstrak tesis yang dikemukakan kepada Senat Universiti Putra Malaysia sebagi memenuhi keperluan untuk ijazah Master Sains

KORELASI AKRILAMIDA DENGAN PREKURSOR DAN WARNA DALAM

KENTANG BEKU SEPARUH MASAK YANG DIGORENG

Oleh

BABAK HATAMI BAROOGH

April 2012

Pengerusi: Professor Jinap Selamat, PhD

Fakulti: Sains Makanan dan Teknologi

Tujuan kajian ini adalah untuk mengesahkan berlakunya pembentukan akrilamida

selepas menggoreng dan mengkaji perkaitan antara kandungan akrilamida dengan asid

amino, gula penurun dan kandungan lembapan di dalam sampel kentang goreng beku,

juga untuk menyiasat pembentukan akrilamida dan kandungan gula penurun sebagai

prekursor utama pada tarikh pengeluaran dan kilang pengeluaran kentang goreng beku

yang berbeza. Analisis akrilamida berdasarkan teknik kromatografi gas spektrometrik

(GC-MS) yang melibatkan pengekstrakan dan derivatization sebelum analisis. Asid

amino dan gula penurun ditentukurkan mengikut kaedah kromatografi cecair

berprestasi tinggi (HPLC). Ia telah ditemui bahawa menggoreng menjana 76.04-348.55

�g / kg akrilamida dalam sampel kentang goreng oleh pelbagai kandungan gula penurun

dalam bentuk fruktosa dan glukosa (0.11-1.30 dan 0.096-1.294 mg / g, masing-masing)

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dan 15 asid amino bebas (0.01-9.17 mg / g) yang telah dikesan dalam sampel kentang

goreng beku sebelum goreng. Walaupun, kandungan asparagine (2.76-9.17 mg / g)

adalah lebih tinggi di kalangan asid amino bebas yang lain, bagaimanapun, threonin dan

glutamin menunjukkan korelasi yang lebih tinggi dengan kandungan akrilamida. Di

samping itu, antara gula penurun, terdapat hubungan yang signifikan antara glukosa dan

kandungan akrilamida dan akrilamida dengan pembangunan warna (�a). Dapat

disimpulkan korelasi akrilamida dan prekursor dalam kentang goreng beku tidak sama

seperti kentang goreng segar. Dalam bahagian kedua, tiada perbezaan yang signifikan

antara purata kandungan akrilamida dan gula penurun bagi jenama yang berbeza (P>

0.05) dan tiada perbezaan yang signifikan (P> 0.05) antara gula penurun dan kandungan

akrilamida bagi dua tuaian tahun (2008-2009), walaupun; akrilamida kandungan pada

tahun 2009 adalah lebih tinggi daripada 2008. Kajian juga menunjukkan bahawa

perubahan iklim dari 2008 hingga 2009 tidak mempunyai kesan yang ketara ke atas

kandungan akrilamida dalam produk ini. Kandungan akrilamida dibentuk selepas

menggoreng kentang goreng beku daripada dua belas bulan pengeluaran dalam tempoh

dua tahun ini berbeza secara signifikan (P <0.05). Kandungan tertinggi akrilamida

(348.55�g/kg) telah dijumpai dalam sampel pada bulan Januari yang menunjukkan

perbezaan yang ketara di kalangan bulan-bulan yang lain. Jumlah terendah akrilamida

(76.04�g/kg) telah dijumpai dalam sampel yang dihasilkan pada September.

.

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ACKNOWLEDGEMENTS

I want to thanks God for enabling me to complete my research.

I would like to express my deepest gratitude to my chair person of the supervisory

committee, Professor Dr. Jinap Selamat who was a great source of motivation, support

and scientific supervision throughout our research. You have worked in such a good

harmony that made my research life enjoyable, the way you helped me to shape my

ideas has eased up all the hard work. All your efforts are really appreciated. I am also

deeply appreciated her for arranging of the necessary funding and financial supporting.

Your endless support and encouragements made me crave for more and more research. I

am full of thanks to my supervisory committee members, Associate Professor Dr. Md.

Zaidul Islam Sarker and Dr. Alfi Khatib for their valuable contribution and suggestions.

Your enthusiastic discussions and ideas have opened up a whole new horizon in my

scientific thinking. My dear friends in Food Safety Lab, Dr. Parvaneh, Gissia,

Maimunah, Wendy and Diana, Thanks for your all cooperation and friendly chats we

shared. I always enjoyed your critics and cultural discussions. I am appreciated to Mrs

linawatti, Mrs. Liza, Mr. Halim, Mr. Azman, for their helps during laboratory

experiments. My deepest appreciation and thanks to my family members who had been

constantly supporting me. I love you all and thank you for loving me and being great

familly.

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I certify that an Examination Committee met on 26/04/2012 to conduct the final examination of Gisia Daniali on his Mst degree of Food Science thesis entitled “Determination of acrylamide in banana-based snack and the effect of precursors on the acrylamide formation” in accordance with Universiti Pertanian Malaysia (Higher Degree) Act 1980 and Universiti Pertanian Malaysia (Higher Degree) Regulations 1981. The committee recommends that the student be awarded the Master of Science degree. Members of the Examination Committee are as follows:

Lasekan Olusegun Associate Professor Dr. Faculty of Food Science and Technology Universiti Putra Malaysia (Chairman) Faridah Abas Associate Professor Dr. Faculty of Food Science and Technology Universiti Putra Malaysia (Internal Examiner) Seyed Hamed Mirhosseini Dr. Faculty of Food Science and Technology Universiti Putra Malaysia (Internal Examiner) Bahruddin Saad Professor Dr. School of Chemistry Universiti Sains Malaysia (External Examiner)

SEOW HENG FONG, PhD Professor and Deputy Dean School of Graduate Studies

Date:

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This thesis was submitted to the Senate of Universiti Putra Malaysia and has been accepted as fulfilment of the requirement for the degree of Master of Science. Members of the Supervisory Committee were as follows.

Jinap Selamat, PhD Professor Faculty of Food Science and Technology Universiti Putra Malaysia (Chairman) MD Zaidul Islam Sarker, PhD Associate Professor Faculty of Food Science and Technology Universiti Putra Malaysia (Member) Alfi Khatib, PhD Lecturer Faculty of Food Science and Technology Universiti Putra Malaysia (Member)

BUJANG BIN KIM HUAT, PhD Professor and Dean School of Graduate Studies Universiti Putra Malaysia

Date:

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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 is not concurrently submitted for any other degree at Universiti Putra Malaysia or at any other institutions.

BABAK HATAMI BAROOGH

Date: 26 April 2012

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TABLE OF CONTENTS

Page ABSTRACT iii ABSTRAK v ACKNOWLEDGEMENTS vii APPROVAL viii DECLARATION x LIST OF TABLES xiv LIST OF FIGURES xvi LIST OF ABBREVIATIONS xx

CHAPTER

1 INTRODUCTION 1

1.1 Background of study 1

1.2 Objectives 3

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2 LITERATURE REVIEW 4

2.1 Frozen par fried French fries 4

2.2 Climate change and potato crops 7

2.3 Chemistry of acrylamide 9

2.4 Occurrence of acrylamide in food 11

2.5 Metabolism and toxicology of acrylamide 13

2.6 Acrylamide dietary exposure 15

2.7 Acrylamide formation 15

2.7.1 Formation from acrolein 16

2.7.2 Formation from Maillard reaction 17

2.8 Factors affecting the acrylamide formation 19

2.8.1 Potato variety and storage condition 20

2.8.2 Potato tuber size and underwater weights 20

2.8.3 Climate changes in growing seasons 21

2.8.4 Amino acids and reducing sugars contents 21

2.8.5 Moisture content 22

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2.8.6 pH 22

2.8.7 Blanching 23

2.8.8 Frying oil 24

2.8.9 Frying temperature 24

2.8.10 Frying time 26

2.9 Analytical methods for acrylamide precursors detection 27

2.9.1 Amino acids analysis 27

2.9.2 Reducing sugar analysis 28

2.10 Analytical method for acrylamide detection 29

2.10.1 Determination by GC-MS 30

2.10.2 Determination by LC-MS/MS 31

3 MATERIALS AND METHODS 32

3.1 Chemicals and instruments 32

3.2 Collection and Preparation of samples 33

3.2.1 Frying of samples 33

3.3 Analysis of acrylamide 34

3.3.1 Acrylamide extraction 34

3.3.2 GC-MS analysis 35

3.3.3 Calibration, LOD and LOQ 36

3.3.4 Recovery test 39

3.4 Analysis of glucose, fructose and sucrose 39

3.5 Analysis of free amino acids 40

3.5.1 Protein hydrolysis 40

3.5.2 Sample preparation and derivatization 40

3.5.3 Amino acid determination 41

3.6 Moisture analysis 42

3.7 Color measurement 42

3.8 Statistical analysis 42

�4 RESULTS AND DISCUSSION 45

4.1 The content of acrylamide, amino acids, reducing sugars and moisture in frozen

French fries 45

4.2 Correlation of acrylamide content with amino acids, reducing sugars and moisture 47

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4.2.1 Correlation of acrylamide with amino acids 49

4.2.2 Correlation of acrylamide with sugars 56

4.2.3 Correlation of acrylamide with moisture content 57

4.3 Correlation of acrylamide with color development 57 4.4 acrylamide formation and reducing sugar content in different production date and plant in frozen French fries samples 65

4.4.1 Impact of production month on acrylamide formation in frozen French fries samples 68

4.4.2 Impact of production year on acrylamide formation in frozen French fries samples 71 4.4.3 Impact of production plant (brand) on acrylamide formation in frozen par French fries samples 76

5 SUMMARY, GENERAL CONCLUSION AND RECOMMENDATION FOR FUTURE RESEARCH 81

5.1 Conclusion 81

5.2 Recommendation 84

�REFERNCES 86 APPENDICES 96 BIODATA OF STUDENT 112 LIST OF PUBLICATIONS 113