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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