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UNIVERSITI PUTRA MALAYSIA
PRESERVATION OF YELLOW ALKALINE NOODLES USING DIFFERENT RADIATION TECHNOLOGIES
ANISSA SORAYA
FSTM 2011 8
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PRESERVATION OF YELLOW ALKALINE NOODLES USING
DIFFERENT RADIATION TECHNOLOGIES
By
ANISSA SORAYA
Thesis Submitted to the School of Graduate Studies, Universiti Putra Malaysia, in Fulfilment of the Requirements
for the Degree of Master of Science
June 2011
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DEDICATION
To my beloved family. The people I love the most
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Abstract of thesis presented to The Senate of Universiti Putra Malaysia in fulfilment of the requirement for the degree of Master of Science
PRESERVATION OF YELLOW ALKALINE NOODLES USING DIFFERENT
RADIATION TECHNOLOGIES
BY
ANISSA SORAYA
June 2011 Chairman : Assoc. Prof. Roselina Karim, PhD
Faculty : Food Science and Technology
Yellow alkaline noodles (YAN) are very susceptible to spoilage. Currently,
boric acid, a carcinogenic compound, was commonly applied as YAN
preservative. The present study was conducted to investigate feasible
radiation technologies to produce preservative-free yet long life YAN. These
included applying gamma irradiation to improve the microbiological quality of
wheat flour which was used as the main raw material, and post processing
treatment using combination of microwave (MW) and pulsed-Ultra Violet
(pulsed-UV) to reduce the microbiological contamination of YAN.
Wheat flour for making noodles was irradiated using a 60Co Gamma ray at
six different doses (0, 2, 4, 6, 8 and 10 kGy). The chemical composition,
physicochemical properties, and microbiological quality of wheat flour were
analysed. The irradiated flours were used for making YAN. The colour
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quality, textural properties, cooking quality, and the microbiological quality of
YAN were analysed.
Gamma irradiation did not cause any significant (P > 0.05) change on the
chemical composition of wheat flour, whereas it caused significant changes (P
< 0.05) in the physicochemical properties of wheat flour and YAN made from
it. Gamma irradiation significantly (P < 0.05) reduced total microorganism
load in wheat flour and YAN. All textural parameters of YAN were
significantly (P < 0.05) affected by irradiation, except for springiness. In term
of cooking quality, the cooking time was unaffected by irradiation, whereas
cooking loss were significantly (P < 0.05) increased as the irradiation dose
was increased. These findings confirmed that gamma irradiation was
effective in reducing the microorganism load in wheat flour but it affected the
physicochemical properties of wheat flour and resulted in undesirable textural
properties and cooking quality of YAN. Therefore, this treatment was not
applied in further study.
Spoilage of YAN might also be caused by cross contamination from the
environment during noodles preparation. Therefore, the post-processing
decontamination treatment is deemed necessary. Combination of pulsed-UV
and microwave treatment was chosen to reduce the microorganism load in
YAN. Factorial design was employed to study the effect of microwave heating
time at a power of 900 W (2450 MHz) and pulsed-UV energy level on the
microbiological quality and textural properties of YAN. Twenty combinations
of different microwave heating times (0 to 10 s) and pulsed-ultra violet energy
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level (0 to 7 J/cm2) were applied on the parboiled YAN. The response
optimiser was applied to determine the optimum combination of these
technologies in reducing the microorganism load in YAN without causing
detrimental effects in the textural properties.The results of this study showed
that the optimum combination is 5 s of microwave at power of 900 W (2450
MHz) followed by 3.5 J/cm2 pulsed-UV treatment.
YAN was treated using the optimum combination of microwave and pulsed-
UV and stored at ambient (28±2 oC) and chilled (4±2 oC) temperature. The
results showed that the shelf life of treated YAN at ambient and chilled
temperatures were 1.5 days and 3.6 weeks, respectively, while, the shelf life
of untreated YAN (control) at ambient and chilled temperatures were 0.5 day
and 2 weeks, respectively.
In general, it can be concluded that gamma irradiation in the dose tested is
not feasible for the decontamination of wheat flour. Meanwhile, application of
combination microwave heating followed by pulsed-UV treatment was found
to be effective in reducing the microorganism load in YAN. Combination of
this treatment with chilled storage could further improve the YAN shelf life. A
new processing method for extending the shelf life of preservative-free YAN
was discovered and it can be proposed as an alternative processing method
to replace the current practices.
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Abstrak tesis dikemukakan kepada Senat Universiti Putra Malaysia sebagai memenuhi keperluan Ijazah Sarjana Sains
PENGAWETAN MEE KUNING BERALKALI MENGGUNAKAN BERBAGAI TEKNOLOGI PENYINARAN
Oleh
ANISSA SORAYA
Jun 2011
Pengerusi : Prof. Madya Roselina Karim, PhD
Fakulti : Sains dan Teknologi Makanan
Mee kuning beralkali sangat rentan terhadap kerosakan. Saat ini, asid borik,
suatu zat karsonogenik, banyak digunakan sebagai bahan pengawet mee
kuning beralkali. Kajian ini dijalankan untuk menyelidik teknologi penyinaran
yang mempunyai potensi memproduksi mee kuning beralkali bebas zat awet
dan tahan lama. Ini termasuklah mengaplikasikan sinaran gamma untuk
memperbaiki kualiti mikrobiologi tepung gandum yang digunakan sebagai
bahan mentah utama, dan perlakuan pasca pemprosesan dengan
menggunakan kombinasi teknologi untuk mengurangkan beban
mikroorganisma mee kuning beralkali.
Tepung gandum komersial yang digunakan untuk membuat mee kuning
beralkali diberi perlakuan menggunakan sinaran gamma 60Co pada enam
dos yang berbeza iatu 0, 2, 4, 6, 8 dan 10 kGy. Kandungan kimia, sifat
fizikokimia, serta kualiti mikrobiologi daripada tepung gandum dianalisis.
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Tepung gadum yang telah diberi perlakuan sinaran gamma digunakan untuk
membuat mee kuning beralkali. Ciri warna, sifat tekstur, kualiti memasak,
dan kualiti mikrobiologi mee kuning dianalisis.
Perlakuan dengan sinaran gamma tidak menyebabkan perubahan yang
signifikan (P > 0.05) pada tepung gandum, namun ia mengakibatkan
perubahan signifikan (P < 0.05) pada sifat fizikokimia tepung gandum dan
mee kuning beralkali yang terbuat dari padanya. Perlakuan sinaran gamma
menurukan beban mikroorganisma dalam tepung gandum dan mee kuning
beralkali secara signifikan (P < 0.05). Semua parameter tekstur mee kuning
beralkali dipengaruhi oleh perlakuan penyinaran gamma secara signifikan (P
< 0.05), kecuali untuk keanjalan. Dari segi kualiti memasak, masa memasak
mee kuning beralkali tidak berubah dengan perlakuan sinaran gamma,
namun kehilangan padatan akibat proses memasak mee meningkat secara
signifikan (P < 0.05) dengan peningkatan dos sinaran gamma. Penemuan ini
menegaskan bahawa perlakuan sinaran gamma berkesan untuk
mengurangkan pencemaran mikrobial pada tepung gandum tetapi ia
mempengaruhi sifat fizikokimia tepung gandum dan menghasilkan mee
kuning beralkali yang memiliki sifat tekstur dan kualiti memasak yang tidak
diingini. Oleh kerananya, perlakuan ini tidak diaplikasikan pada tahap
penyelidikan berikutnya
Selain pencemaran dari tepung gandum, kerosakan mee kuning beralkali
mungkin juga disebabkan oleh pencemaran silang dari ruang sekitaran
semasa penyediaan mee kuning. Oleh kerana itu, perlakuan dekontaminasi
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pasca pemprosesan amatlah diperlukan. Kombinasi antara perlakuan pulsa-
ultra ungu dan pemanasan dengan gelombang mikro mempunyai potensi
untuk digunakan sebagai proses dekontaminasi pada mee kuning beralkali.
Reka bentuk faktorial digunakan untuk mengkaji pengaruh pemanasan
gelombang mikro pada aras kuasa 900 W (2450 MHz) dan perlakuan pulsa-
ultra ungu pada kualiti mikrobiologi dan sifat tekstur mee kuning beralkali.
Dua puluh kombinasi masa pemanasan dengan gelombang mikro yang
berbeza (0 hingga 10 saat) dan aras tenaga pulsa-ultra ungu (0 hingga 7
J/sm2) diberi pada mee kuning separa masak. Pengoptimuman respons
digunakan untuk menentukan kombinasi optimum dari pada kedua teknologi
ini dalam menurunkan beban mikroorganisma tanpa mengakibatkan
kerosakan tekstur. Hasil kajian menunjukkan bahawa kombinasi optimum
adalah pemanasan dengan gelombang mikro selama 5 saat pada aras kuasa
900 W (2450 MHz) diikuti dengan perlakuan pulsa-ultra ungu dengan tenaga
sebanyak 3.5 J/sm2.
Mee kuning beralkali diberi perlakuan dengan menggunakan kombinasi
optimum pemanasan dengan gelombang mikro dan perlakuan pulsa-ultra
ungu lalu disimpan pada suhu ambien (28±2 oC) dan pada keadaan sejuk
(4±2 oC). Hasil kajian menunjukkan bahawa jangka hayat mee kuning
beralkali yang diberi perlakuan adalah 1.5 hari pada suhu ambien dan 3.6
minggu pada suhu sejuk. Sementara itu, jangka hayat mee kuning beralkali
tanpa perlakuan adalah 0.5 hari pada suhu ambien dan 2 minggu pada suhu
sejuk.
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Secara umumnya, dapat disimpulkan bahawa perlakuan penyinaran gamma
pada dos yang dikaji tidak sesuai untuk dekontaminasi tepung gandum.
Sementara itu, kombinasi pemanasan gelombang mikro diikuti oleh
perlakuan pulsa-ultra ungu berkesan untuk mengurangkan beban
mikroorganisma dalam mee kuning beralkali. Kombinasi perlakuan tersebut
dengan penyimpanan sejuk boleh memanjangkan lagi jangka hayat mee
kuning beralkali. Satu kaedah pemprosesan untuk memanjangkan jangka
hayat mee kuning yang berkhasiat dan bebas dari bahan awet telah ditemui
dan dapat menggantikan kaedah pemprosesan yang sedia ada.
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ACKNOWLEDGEMENTS
First and foremost my gratitude is to Allah S.W.T. for giving me strength to
complete this thesis. I wish to express my deepest gratitude to Dr. Roselina
Karim, my main supervisor, for her patience, support, guidance, and advice
toward completion of this thesis. My appreciations go to my co-supervisors;
Associate Professor Dr. Sharifah Kharidah, Dr. Farinazleen Mohd. Ghazali,
and Mr. Dzulkifly Mat Hashim for their encouragement and support.
I would like to thank the Malaysian Institute of Nuclear Technology for
providing the irradiation facility. Thanks to all the staff of Faculty of Food
Science and Technology, especially the Food Processing Lab and Food
Microbiology Lab staff; Mr. Razali, Ms Jamaliah, Mr. Zulkifly, Ms Fatihah, and
Ms Kamariah for their help in the project. A special thanks to all my lab
mates, especially; Dila, Yasmeen, Teza, Ms Zauyah, Jie Ying, thank you so
much for the help and unforgettable moments. To all the Indonesian students
in UPM, especially my dorm mates in K2 (Kak Shinta, Kak Lina, Mba dian,
Mini, Gita, Bu Yetti, and Rudi), thank you for the moment we shared together.
I would also like to thank Yayasan Khazanah for providing me the
scholarship since April 2008. Last but not least, I want to thank my family and
Mohamad Amarullah, for their love, support, and encouragement throughout
my study.
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I certify that an examination committee has met on date/month/year to conduct the final examination of Anissa Soraya on her Master of Science thesis entitled “Preservation of Yellow Alkaline Noodles Using Different Radiation Technologies” 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.
Members of the Examination Committee were as follows:
Azizah Abdul-Hamid, PhD Assoc. Professor Faculty of Food Science and Technology Universiti Putra Malaysia (Chairman) Russly Abdul Rahman, PhD Professor and Deputy Dean Faculty of Food Science and Technology Universiti Putra Malaysia (Internal Examiner) Tan Chin Ping, PhD Assoc. Professor Faculty of Food Science and Technology Universiti Putra Malaysia (Internal Examiner) Amiza Mat Amin, PhD Assoc. Professor Department of Food Science, Faculty of Food Science and Agrotechnology Universiti Malaysia Terengganu Malaysia (External Examiner) NORITAH OMAR, Ph.D
Professor and Deputy Dean School of Graduate Studies Universiti Putra Malaysia 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. The members of the Supervisory Committee were as follows:
Roselina Karim, PhD Assoc. Professor Faculty of Food Science and Technology Universiti Putra Malaysia (Chairman) Sharifah Kharidah Syed Muhammad, PhD Assoc. Professor Faculty of Food Science and Technology Universiti Putra Malaysia (Member) Farinazleen Mohd Ghazali, PhD Faculty of Food Science and Technology Universiti Putra Malaysia (Member) Dzulkifly Mat Hashim, MSc Faculty of Food Science and Technology Universiti Putra Malaysia (Member)
HASANAH MOHD GHAZALI, PhD Professor and 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 is not concurrently, submitted for any other degree at Universiti Putra Malaysia or at any other institution.
ANISSA SORAYA
Date: 13 June 2011
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TABLE OF CONTENTS
DEDICATION iii ABSTRACT iv ABSTRAK vii ACKNOWLEDGEMENTS xi
DECLARATION xiv TABLE OF CONTENTS xv LIST OF TABLE xviii LIST OF FIGURE xix LISTS OF ABBREVIATION
xx
CHAPTER
1 INTRODUCTION 1
2 LITERATURE REVIEW 5 2.1 Noodles 5 2.2 Classification and Sensory Characteristic of
Noodles
6
2.3 Yellow Alkaline Noodles 8 2.3.1 Production of yellow alkaline noodles 9
2.3.2 Quality characteristics of yellow alkaline noodles
11
2.3.3 Factor affecting quality of yellow alkaline noodles
14
2.4 Preservation Technology 19 2.4.1 Gamma irradiation 20 2.4.2 Pulsed-ultra violet sterilization 23 2.4.3 Microwave sterilization 27
2.4.4 Combination of preservation technologies 28 2.4.5 Preservation technology of YAN 29
3 EFFECT OF IRRADIATED WHEAT FLOUR ON THE
PHYSICOCHEMICAL, TEXTURAL PROPERTIES, AND COOKING QUALITY OF YELLOW ALKALINE NOODLES
31
3.1 Introduction 31
Page
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3.2 Materials and Methods 32
3.2.1 Materials 32
3.2.2 Flour treatment 33 3.2.3 Noodles preparation 33 3.2.4 Chemical composition and physicochemical
properties analysis of wheat flour 34
3.2.5 Colour properties analysis of YAN 35
3.2.6 Textural properties analysis of YAN 35 3.2.7 Cooking quality of YAN 36 3.2.8 Microbiological analysis of wheat flour
and YAN 37
3.2.9 Experimental design and data analysis
37 3.3 Results and Discussion 38 3.3.1 Microbiological quality of wheat flour 38 3.3.2 Chemical composition and physicochemical
properties of wheat flour
40
3.3.3 Microbiological quality of YAN 46 3.3.4 Physicochemical, textural, and cooking
quality of YAN
48
3.4 Conclusions 54
4 OPTIMIZATION OF COMBINATION OF MICROWAVE AND PULSED-UV TREATMENT FOR REDUCING THE MICROORGANISM LOAD OF YELLOW ALKALINE NOODLES
56
4.1 Introduction 56 4.2 Materials and Methods 58 4.2.1 Materials 58 4.2.2 YAN preparation 58 4.2.3 Microwaves and pulsed-UV treatment 58 4.2.4 Microbiological analysis 59 4.2.5 Textural analysis 59 4.2.6 Experimental design and data analysis 60
4.3 Results and Discussion 60 4.3.1 Effect of the combination of microwave and
pulsed-UV treatments on the microbiological quality of YAN
63
4.3.2 Effect of the combination of microwave and pulsed-UV treatments on the textural profile of YAN
66
4.3.3 Determination and validation of optimum combination
67
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4.4 Conclusions 68
5 STORAGE STABILITY OF YELLOW ALKALINE NOODLES TREATED USING THE OPTIMUM COMBINATION OF MICROWAVE AND PULSED-UV
69
5.1 Introduction 69 5.2 Materials and Methods 70 5.2.1 Materials 70 5.2.2 YAN preparation and treatment 70 5.2.3 Microbiological analysis 71 5.2.4 Determination of pH 71 5.2.5 Textural profile analysis 71 5.2.6 Moisture content determination 72 5.2.7 Experimental design and data analysis 72
5.3 Results and Discussion 72 5.3.1 Microbiological quality 72 5.3.2 The moisture content and pH value of YAN 79 5.3.3 The Textural profile of YAN 81 5.4 Conclusions 85
6 GENERAL CONCLUSIONS AND RECOMMENDATIONS 87
REFERENCES 90
APPENDICES 104
BIODATA OF STUDENT 112
PRESERVATION OF YELLOW ALKALINE NOODLES USING DIFFERENT RADIATION TECHNOLOGIESABSTRACTTABLE OF CONTENTSCHAPTERSREFERENCES