PUMS 99:1 UNIVERSITI MALAYSIA SABAH

BORANG PENGESAHAN STATUS TESIS

JUDUL: __ A_('\_rt_; _o)<.._i _cLo,_(\_t_A_c.-i_;_v ;--,i1~c-,-f __ $_lA_b_O-_h-_ P-i_,UL __ B_I'cx.r\. __________ _

DAZAH: __________ ~------~~t-o-v-~---Q-~-· ~--~----~--;+-~----H-o-n-D-v-r_r __ ;_n~_oo_d ___ T_e_th_~_o_(~~~--~----

I brY1Jl.LS' SESI PENGAJIAN: ___ ~_o_o ...:..1 _JL._J_O_l _o __ _

s~a ______ ~_~_~_f_N ___ ~_O_O ________ ~====~~~--------------------------(HURUF BESAR)

blengaku membenarkan tesis (LPSI Satjana/ Doktor Falsafah) ini di simpan di Perpustakaan Universiti Malaysia Sabah dengan syarat-syarat kegunaan seperti berikut:

1. Tesis adalah hakmilik Universiti Malaysia Sabah. 2. Perpustakaan Universiti Malaysia Sabah dibenarkan membuat salinan untuk tujuan pengajian sahaja. 3. Perpustakaan dibenarkan membuat salinan tesis ini sebagai bahan pertukaran antara institusi pengajian tinggi. 4. ** Sila tandakan ( I )

SULIT

TERHAD

'--__ 7---" TIDAK TERHAD

~~ (TANDAT ANGAN PENULIS)

~lamat TetaP: __ 5'-6-ff_.J_o._{_o..r._~_~_·_'h-=CV\__'___;)_r

T o..../Y\o.r- f>l..Le0~ 1\Il0J\ ~------------------------,----

14000 pu.}:.1t-f M.e/t~OVV\

':) t / 5/ ~ DI 0

. r A TAN: * Potong yang tidak berkeoaan.

(Mengandungi maklumat yang berdarjah keselamatan . atau kepentingan Malaysia seperti yang termaktub di dalam AKTA RAHSIA RASMI 1972)

(Mengandungi maklumat TERHAD yang telah ditentukakan oleh organisasilbadan di mana peoyelidikan dijalankan)

Nama Peoyelia

Tarikh: :> I / ; / .) 01.(0 ------~~-----------------

* Jika tesis ioi SULIT atau TERHAD, sila lampiran surat daripada pihak berkuasalorgansasi berkenaan deogan meoyatakan sekali sebab dan tempoh tesis ioi perlu dikelaskan sebagai SULIT danTERHAD.

* Tesis dimaksudkan sebagai tesis bagi Ijazah Doktor Falsafah dan Sarjana secara penyelidikan, atau disertasi bagi pengajian seeara kerja kursus dan penyelidikan, atau Laporan Projek Sarjana Muda (LPSM).

ANTIOXIDANT ACTIVITY OF SABAH RICE BRAN

KAREN LOO

DISSERTATION SUBMITTED IN PARTIAL FULFILLMENT FOR THE DEGREE OF FOOD

SCIENCE WITH HONOURS IN FOOD TECHNOLOGY AND BIOPROCESS

SCHOOL OF FOOD SCIENCE &. NUTRITION UNIVERSITY MALAYSIA SABAH

2010

DECLARATION

I hereby declare that the material in this thesis is my own except for quotations, excerpts, equation and references which have duly acknowledged.

16th April 2010

ii

KAREN LOO

HN2006-3600

NAME

MATRICE NO.

mLE

DEGREE

VIVA DATE

1. SUPERVISOR Madam Fan Hui Yin

2. EXAMINER I

CERTIFICATION

KAREN LOO

HN2006-3600

ANTIOXIDANT ACTIVITY OF SABAH RICE BRAN

FOOD SCIENCE WITH HONOURS IN FOOD TECHNOLOGY AND BIOPROCESS

13th May 2010

DECLARED BY

Prof. Madya Dr. Chye Fook Yee

3. EXAMINER II ~.

Prof. Madya Dr. Mohd. Ismail Abdullah

4. DEAN Prof. Madya Dr. Mohd. Ismail Abdullah

~.

iii

ACKNOWLEDGEMENT

First and foremost I offer my sincerest gratitude to my supervisor, Madam Fan Hui Yin, whose encouragement, guidance and support throughout this project enabled me to develop an understanding of this study. It is a pleasure to thank those who made this thesis possible like all the lecturers in School of Food Science and Nutrition. They had taught and presented us information and knowledge throughout my four years studies at University Malaysia Sabah that one needs as a fundamental to embark on his or her project and thesis.

lowe my deepest gratitude to my parents and family who support me throughout all my studies at University Malaysia Sabah. Their financial supports especially assist me with all the costs and expenses for this study. Besides that, I am heartily grateful to a special friend, Kyle Wong Cheok Liang. He has made available his support in a number of ways from the initial to the final levels of this project. These people essentially teaching me everything I know about sense of commitment to my work and responsibility, have often had to bear the brunt of my frustration and rages against the problems I encountered throughout this study.

This thesis would not have been possible unless with the helps from my beloved friends especially Tong Woei Venn, Tan Ying Ying, Khow Hong Yi and Khor Qiongzhi. Their specialty and experiences in research have contributed enormous benefits for me in understanding my study better. I am also indebted to many coursemates, master students and lab assistants especially Yong Sui King, Oon Xin Van and Ms. Wong for teaching and guiding me in running the instrument during laboratories. Furthermore, I would like to show my gratitude to friends who were studying the same sample under Madam Fan's supervise especially Chaw Siew Wen and Chew Huey Ming for providing and passing on information to me.

I am also very grateful to Guan Onn Milling Factory for supplying rice bran samples to complete this study without any charges. Lastly, I offer my regards and blessings to all of those who supported me in any aspect during the completion of this study.

KAREN LOO

9th April 2010

iv

ABSTRACT

The study was aimed to determine the antioxidant activity and total phenolic content (TPC) of Sabah rice bran using the Folin-ciocalteau method, l,l-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, ferric reducing antioxidant power (FRAP), ferrous ion-chelating (FIC), and lipid peroxidation inhibition (LPI) assay. The effects of different stabilization methods (i.e. microwave heating and refrigeration) on TPC and antioxidant activity were also studied. Three varieties of Sabah rice bran namely MR159, TQR2 and Sarawak were selected. All the studied samples contained different phenolic contents with higher concentration in microwave heated samples than refrigerated samples among varieties. Microwave heating shows the order of Sarawak > MR159 > TQR2 while refrigeration shows the order of Sarawak > TQR2 and MR159. In corresponding way, microwave heated samples exhibited significantly stronger DPPH scavenging activity, FRAP and LPI compared to refrigerated sample of any particular varieties in present study by referring to ECso value. In contrast, refrigerated samples exhibit better FIC activity than microwave heated samples. Rice bran Sarawak overall possessed the strongest AOA in all assay except for FIC assay. With regard to this assay, the antioxidant efficacy of TQR2 was the highest among the studied varieties. Similar orders were observed in TPC and FRAP among the varieties for both stabilization treatment. Contents of total phenols of rice bran were positively correlated with the DPPH scavenging activity (r= 0.6895), FRAP (r= 0.8354) and LPI (r= 0.6995). Based on the result obtained, stabilized Sabah rice bran possessed effective antioxidant properties.

v

ABSTRAK

AKTIVITI ANTIOKSIDAN DEDAK BERAS SABAH

Penyelidikan ini bertujuan untuk menentukan aktiviti antioksidan dan kandungan jumlah sebatian fenolik dedak beras Sabah dengan menggunakan kaedah seperti reagen Folin-ciocalteu, aktiviti penjerapan DPPH, kuasa penurunan antioksidan, pengkhelatan ion besi dan penghambatan peroksidasi lipid. Kesan terhadap jumlah kandungan sebatian fenolik dan aktiviti antioksidan oleh cara-cara penstabilan (iaitu pemanasan microwave dan pendinginan) juga dise/idik. Tiga jenis varieti dedak beras Sabah yakni MR159, TQR2 dan Sarawak te/ah dipi/ih untuk dija/ankan kajian antioksidan. Semua sam pel yang dikaji mengandungi jumlah kandungan sebatian fenolik yang berlainan di mana sampel dengan pemanasan microwave adalah lebih banyak berbanding dengan sampel dengan pendinginan. Dengan itu, bagi semua varieti yang dikaji, sampel dengan pemanasan microwave mempunyai aktiviti penjerapan DPPH, kuasa penurunan antioksidan dan penghambatan peroksidasi lipid yang lebih kuat berbanding dengan sampel yang distabil secara pendinginan dengan merujuk kepada nilai ECso• Seba/iknya, sam pel yang distabi/ secara pendinginan mempamerkan aktiviti pengkhe/atan ion besi yang lebih tinggi. Secara umumnya, dedak beras varieti Sarawak merupakan varieti yang menunjukkan aktiviti antioksida yang terkuat dalam semua kaedah kajian kecuali da/am pengkhelatan ion besi. Sebaliknya, TQR2 adalah yang paling kuat dalam kaedah tersebut antara mereka yang dikaji. Urutan varieti yang sama telah diperhatikan dalam jumlah kandungan sebatian feno/ik dengan aktiviti penjerapan DPPH bagi kedua-dua penstabilan. Kandungan sebatian fenolik dedak beras mempunyai hubungan yang positive dengan aktiviti penjerapan DPPH (r= 0.6895), kuasa penurunan antioksidan (r= 0.8354) dan penghambatan peroksidasi lipid (r= 0.6995). Dengan keputusan yang didapati, dedak beras Sabah yang telah distabil mempunyai sifat antioksidan yang berkesan.

vi

TABLE OF CONTENTS

TITLE

DECLARATION

CERTIFICATION

ACKNOWLEDGEMENT

ABSTRACT

ABSTRAK

LIST OF CONTENTS

LIST OF TABLES

LIST OF FIGURES

LIST OF EQUATIONS

LIST OF ABBREVIATIONS

LIST OF APPENDICES

CHAPTER 1: INTRODUcnON

1.1 Overview 1.2 Objective

CHAPTER 2: LITERATURE REVIEW

2.1 Free Radical and Active Oxygen Species 2.2 Antioxidant

2.2.1 Classification of Food Antioxidants 2.3 Source of Food Antioxidants

2.3.1 Synthetic Antioxidants 2.3.2 Natural Antioxidants

2.4 Rice Bran 2.4.1 Rice Bran Production 2.4.2 Rice Bran Composition 2.4.3 Health Benefits of Rice Bran

2.5 Principal Antioxidant Components in Rice Bran 2.5.1 Gamma-oryzanol

vii

Page

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iii

iv

v

vi

x

xi

xii

xiv

xv

1

1 4

5

5 5 7 8 8 9 12 12 13 14 14 15

2.5.2 Tocopherol and Tocotrienol 17 2.6 Factors Affecting on Antioxidant Activity of 18

Rice Bran 2.6.1 Intrinsic Factors 19 2.6.2 Extrinsic Factors 19

2.7 Sample Preparation 22 2.8 Rice Bran Stabilization 23

2.8.1 Free Fatty Acids Formation in Rice Bran 23 2.8.2 Stabilization Methods 24

2.9 Preparation of Sample Extract 26 2.10 Determination of Total Phenolic Content 29 2.11 Determination of Antioxidant Activity 30

2.11.1 2,2'-diphenyl-1-picrylhydrazyl (DPPH) 32 Radical Scavenging Activity Assay

2.11.2 Ferric Reducing Antioxidant Power 34 (FRAP) Assay

2.11.3 Ferrous Ion-Chelating (FIC) Assay 34 2.11.4 Lipid Peroxidation Inhibition (LPI) 36

Assay 2.12 Industrial Application 36

CHAPTER 3: MATERIALS AND METHODS 38

3.1 Chemicals and Materials 38 3.2 Rice Bran Sample 38 3.3 Stabilization Method 38

3.3.1 Microwave Heat Stabilization 38 3.3.2 Cold Stabilization 39

3.4 Preparation of Rice Bran Extract 39 3.5 Determination of Total Phenolic Content (TPC) 39 3.6 Determination of Antioxidant Activity (AOA) 40

3.6.1 2,2'-diphenyl-1-picrylhydrazyl (DPPH) 40 Radical Scavenging Activity Assay

3.6.2 Ferric Reducing Antioxidant Power 41 (FRAP) Assay

3.6.3 Ferrous Ion-chelating (FIC) Assay 41 3.6.4 Lipid Peroxidation Inhibition (LPI) Assay 42 3.6.5 Statistical Analysis 42

CHAPTER 4: RESULTS AND DISCUSSION 43

4.1 The effect of Stabilization Treatment on Rice 43 Bran

4.2 Yield of Methanolic Extracts 44 4.3 Total Phenolic Content 45 4.4 Antioxidant Activity of Methanolic Rice Bran 47

Extract

viii

4.4.1 2,2'-diphenyl-l-picrylhydrazyl (DPPH) 49 Free Radical Scavenging Activity

4.4.2 Ferric Reducing Antioxidant Power 52 (FRAP)

4.4.3 Ferrous ion-chelating (FIC) Activity 53 4.4.4 Lipid Peroxidation Inhibition (LPI) 56

CHAPTER 5: CONCLUSION AND SUGGESTIONS 60

REFERENCES

APPENDICES

5.1 Conclusion 5.2 Suggestions

ix

60 61

63

95

Table 2.1

Table 2.2

Table 4.1

Table 4.2

LIST OF TABLES

Reaction of hydrogen-donating antioxidant with radicals

Classification of food antioxidant

Yield of methanolic extract of microwave heated and refrigerated rice bran

ECSO value (mg/ml) of free radical scavenging activity (DPPH), ferric reducing antioxidant power (FRAP), ferrous ion-chelating activity (FIC), lipid peroxidation inhibition (LPI) of methanolic extracts from stabilized rice bran

x

Page

6

8

44

48

Figure 2.1

Figure 2.2

Figure 2.3

Figure 2.4

Figure 4.1

Figure 4.2

Figure 4.3

Figure 4.4

LIST OF FIGURES

Cross-section of a grain of rough rice

Chemical structures of the four main components of gamma-oryzanol

Structure of tocopherol and tocotrienols and its isomer

Structure of 2,2-diphenyl-1-picrylhydrazyl (DPPH)

Total phenolic content of methanolic rice bran extract

DPPH radical-scavenging activity (%) of different concentration of methanolic extracts from rice brans that stabilized by a) microwave heating and b) refrigeration method.

Ferrous ion chelating activity (%) of different concentration of methanolic extracts from rice brans that stabilized by a) microwave heating and b) refrigeration method.

Lipid peroxidation inhibition (%) of different concentration of methanolic extracts from rice brans that stabilized by a) microwave heating and b) refrigeration method.

xi

Page

13

16

17

33

46

50

54

57

Equation 2.1

Equation 2.2

Equation 2.3

Equation 2.4

Equation 2.5

Equation 3.1

Equation 3.2

Equation 3.3

Equation 3.4

Equation 3.5

LIST OF EQUATIONS

Equation showing single electron transfer mechanisms

Equation showing propagation of free radical inhibited by hydrogen atom transfer mechanisms

Equation representing the reaction between phenolic compound and molybdenum in Folin­ciocalteu reagent

Equation representing reaction between DPPH free radical and antioxidant

Equation representing reaction between FRAP reagent and reducing antioxidant

Equation calculating the yield of sample in percentage

Equation calculating the total phenolic content in sample

Equation calculating the scavenging activity of DPPH free radical

Equation calculating the percentage of FIe effect

Equation calculating the percentage of lipid peroxidation inhibition

xii

Page

7

7

30

33

34

39

40

40

41

42

ABTS

AH

AN OVA

AOA

BHA

BHT

DOA

DPPH

ECso

EDTA

FAO

FFA

FIC

FRAP

GAE

HAT

HCI

HPLC

LDL

LPI

Mo

MRPs

LIST OF ABBREVIATION

2,2' -azi no-bis(3-ethyl benz-th iazoli ne-6-sulfonic

Antioxidant

Analysis of Variance

Antioxidant activity

Butylated hydroxyanisole

Butylated hydroxytoluene

Department of agricultural

2,2-Diphenyl-!-Picrylhydrazyl

Half maximal effective concentration

Ethylenediamine-tetraacetic

Food and Agriculture Organization

Free fatty acid

Ferrous ion-chelating ability

Ferrous reducing antioxidant power

Gallic acid equivalent

Hydrogen peroxide

Hydrogen atom transfer

Hydrochloric acid

High performance liquid chromatography

Low-density lipoprotein

Lipid peroxidation inhibition

Molybdenum

Maillard reaction products

xiii

0 2.- Superoxide anion radicals

OH Hydroxyl radicals

PER Protein efficiency ratio

PG Propyl gallate

R- Alkyl free radical

RO- Alkoxyl free radical

ROO- Peroxyl free radical

ROS Reactive oxygen species

SET Single electron transfer

TBHQ tert-butylhydroquinone

TEAC Trolox equivalent antioxidant capacity

TPC Total phenolic content

TPTZ 2,4,6-trypyridyl-s-triazi ne

USDA United states department of agriculture

UV-Vis Ultraviolet-visible

xiv

Appendix A

Appendix B

Appendix C

Appendix D

Appendix E

Appendix F

Appendix G

Appendix H

Appendix I

Appendix J

Appendix K

Appendix L

Appendix M

LIST OF APPENDICES

Statistic of Paddy Variety in Sabah

Collection of Rice Bran Samples

Samples Preparation

Samples for Analysis

Methanolic Extracts

Calibration Curve of Gallic Acid

Correlation Coefficient (~ Between Total Phenolic Content and Antioxidant Properties

One-way ANOVA for Yield of Methanolic Rice Bran Extract

One-way ANOVA for Determination of Total Phenolic Content

One-way ANOVA for DPPH Radical Scavenging Activity Assay

One-way ANOVA for Ferric Reducing Antioxidant Power Assay

one-way ANOVA for Ferrous lon-Chelating Activity Assay

Independent t-test for Lipid Peroxidation Inhibition Assay

xv

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96

97

98

99

100

101

103

104

105

106

107

108

CHAPTER 1

INTRODUCTION

1.1 Overview

Antioxidant activity (ADA) is defined as the capability of a compound to inhibit

oxidative degradation, for example lipid peroxidation (Roginsky and Lissi, 2005).

Synthetic antioxidants, such as butylated hydroxyanisole (BHA) and butylated

hydroxytoluene (BHn, are those compound commonly used in food to retard lipid

peroxidation during storage (Chu and Hus, 1999). However, many researchers

have reported adverse effects of synthetic antioxidants, such as toxicity and

carcinogenicity (Williams et al., 1999). Safety concern over synthetic antioxidants

have led to an increasing interest in identifying naturally occurring antioxidants

from edible materials, edible by-products and residual sources (Moure et al., 2001).

Rice is the number one food crop in the world (Amarasinghe et al., 2009),

and also the main staple food in Sabah. There are more than fifteen types of rice

varieties planted in Sabah (DDA, 2009). During rice proceSSing, rice bran is

produced as a by-product of rice milling (Saunders, 1990). It is defined as "a by

product of polishing brown rice, comprising the pericarp, aleurone layer, embryo

and some endosperm" by FAD, (1996) and it possesses approximately 10 %

weight of the total rice grain. It is rich in nutrients with 14 % to 16 % protein, 8 %

to 10 % crude fiber and 12 % to 23 % fat especially unsaturated fatty acids

(Drthoefer and Eastman, 2004; McCaskill and Zhang, 1999). It is also a good

source of B vitamins and contains minerals such as iron, potassium, calcium,

chlorine, magnesium and manganese (Saunders, 1985).

Research conducted in last two decades has shown that rice bran contains

a unique complex of naturally occurring antioxidant compounds (Moldenhauer et

al., 2003) which comprise of sterols, higher alcohols, gamma-oryzanol, tocopherols,

tocotrienols and phenolic compounds (Nicolosi et a/., 1994; Aguilar-Garcia et a/.,

2007). These bioavailable materials have shown potential for antioxidant activity

and anti-cancer properties that protect the body from free-radical damage (Nam et

a/., 2005; Xu et a/., 2001). Furthermore, they have the potential to be used as

food ingredient (McCaskill and Zhang, 1999) which helps to improve the storage

stability of foods (Hegsted and Windhauser, 1993). Among these compounds,

oryzanols, tocopherols and tocotrienols have been reported as the strongest

antioxidants in rice bran (Godber and Wells, 1994; Godber and Juliano, 2004;

Orthoefer and Eastman, 2004). Their concentrations can vary substantially

according to the origin or variety of the rice bran (Diack and Saska, 1994; Hu et a/.,

1996; Lloyd et a/., 2000).

Although rice bran has great potential as a supplementary source of many

nutrients, the use of it is limited by its instability caused by hydrolytic and oxidative

rancidity. Immediately following the milling process, rapid deterioration of the

crude fat in the bran by lipase and to a lesser extent oxidase occurs and makes the

bran unfit for human consumption. Therefore, rice bran has only been traditionally

used as a feedstock. To process rice bran into a food grade product of good

keeping quality and high industrial value, all the components causing deterioration

must be removed or their activity arrested (Malekian et a/., 2000). Important in

this aspect is that inactivation of lipase enzymes must be complete and irreversible.

At the same time, the valuable nutrient like antioxidant must be preserved.

Rice bran after proper stabilization can serve as a good source of nutrients

such as tocopherols and ferulic acid derivatives (Malekian et a/., 2000). However,

this postharvest treatment in preserving rice bran could affect the level of

antioxidant activity (Iqbal et a/., 2005). In recent years, use of microwave energy

as an inexpensive source of heat for thermal processing of foods has offered an

alternative energy source for stabilization of rice bran (Rhee and Yoon, 1984).

However, numerous studies found that stabilization technique with heat affects the

antioxidant compound stability (Martin et a/., 1993; Wells, 1993; Nicolosi et a/.,

1994). On the other hand, cold storage or refrigeration that slows down the

enzymatic activity of rice bran to extend it shelf life is another technique that has

2

been practiced (Nasirullah et al., 1989; Amarasinghe et al., 2009). These

processes may either cause negative attribute to rice bran or instead enhanced its

ADA.

Currently, few of studies have documented how initial processing steps of

the postharvest rice bran affect antioxidant retention (Lloyd et al., 2000). No work

has concluded that which stabilization procedure is the most effective in the

interest of enhancing and maximizing antioxidant activity of rice bran although

numerous studies have been conducted on the effect of stabilization technique on

extractability of their antioxidant (Hu et al., 1996; Seetharamaiah Chandrasekhara,

1989; Shin et al., 1997; Amarasinghe et al., 2009). The information is too scanty

to allow processor to process rice bran without losing their functionality. Therefore

is of considerable importance to evaluate stabilization effect on antioxidant activity.

The significance of this study is to provide a valuable basis for developing

Sabah rice bran that previously thought to be worthless as a valuable food additive

to enhance human nutrition via its nutrient such as antioxidant. Information about

the capability of antioxidant compound is more than important as they could be a

major determinant of antioxidant potentials of foods (Parr and Bolwell, 2000).

When exploring the antioxidant potential of rice bran varieties, the use of a single

test is insufficient to identify the different mechanisms involved (Wang et al.,

2008). In present study, four antioxidant assays, DPPH radical scavenging activity,

ferric reducing antioxidant power (FRAP), ferrous ion chelating ability (FIe) and

lipid peroxidation inhibition (LPI) were carried out to evaluate the ADA. Total

phenolic content (TPe) of Sabah rice bran was determined as well. These

mechanisms were studied to explain how rice bran is a source of natural

antioxidant.

3

1.2 Objective

(1) To investigate the antioxidant activities of three varieties of Sabah rice bran;

MR159, TQR2, and Sarawak.

(2) To investigate the effect of different stabilization methods on total phenolic

content and antioxidant activity of Sabah rice bran

4

CHAPTER 2

LITERATURE REVIEW

2.1 Free Radical and Active Oxygen Species

Free radicals and other reactive oxygen species (ROS) which including superoxide

anion radicals (0/-), hydroxyl radicals (OH) and hydrogen peroxide (H20 2) are

highly reactive and potentially damaging transient chemical species formed in

aerobic life. These unwanted metabolic by-products of normal aerobic metabolism

are removed by a variety of endogenous reactive oxygen species scavenging

enzymes and chemical compounds (Halliwell and Gutteridge, 1985). An imbalance

between reactive oxygen species generating and their scavenging systems in cells

leads to oxidative stress, resulting in some oxidative damage to biomolecules such

as lipids, nucleic acids, proteins and carbohydrates (Sies et al., 2005).

Oxidative damage increases the risk of several human chronic diseases,

such as cancer, arteriosclerosis, neurodegenerative disorders, as well as aging

processes (Aruoma, 1998). In term of food system, the oxidative deterioration of

fats and oils in foods especially that induced by ROS is responsible for quality

deteriorations (Laguerre et al., 2007) like rancid odours and flavours, with a

consequent decrease in nutritional quality and safety caused by the formation of

secondary, potentially toxic compounds (Moure et al., 2001). Oxidation leading to

overt rancidity is the second most important cause of food spoilage after microbial

spoilage (Undley, 1998). Therefore, the demand for the efficient inhibitors of

oxidation processes is very essential.

2.2 Antioxidant

The term "antioxidant" is increasingly popular in modern society due to its

beneficial health-related effect (Huang et al., 2005). Antioxidants are generally

defined as any substance that when present in low concentrations compared with

those of an oxidizable substrate, significantly delays or prevents oxidation of that

substrate (Halliwell and Gutteridge, 1985). The negative effects of oxidative stress

may be mitigated by antioxidants (Pryor, 1991; Larson, 1995).

BaSically, antioxidants defense against ROS through three interventions:

prevention, interception and repair. Prevention is the first line of defense against

ROS, that is, protection against ROS formation. However, once the ROS formed,

antioxidants play its role by intercepting a damaging species to prevent further

deleterious reactions. This is the process of deactivation. Since prevention and

interception processes are not completely effective, damaging effects may

continuously occur and damaged products may accumulate. At this stage,

antioxidants can also exert its protective effects by repair of damage (Sies, 1997).

Generally, there are two proposed mechanisms by which antioxidants can play

their protective role which is hydrogen atom transfer (HAT) and single electron

transfer (SET) (Prior et al., 2005). Both of these mechanisms must always occur in

parallel but with different rates (Rojano et al., 2008).

(a) Hydrogen atom transfer (HAT) mechanisms:

In HAT reaction, the antioxidants quench the free radicals by hydrogen

donation (Prior et al., 2005). The antioxidant itself becomes radical.

Table 2.1: Reaction of hydrogen-donating antioxidant with radicals* R- + AH ---. RH + A-

RO- + AH ---. ROH + A-

ROO- + AH ---. ROOH + A-

R- + A- ---. RA

RO- + A- ---. ROA

ROO- + A- ---. ROOA

Antioxidant + O2 ---. Oxidized antioxidant

* AH: antioxidant; R-: alkyl free radical; RO-: alkoxyl free radical; ROO-: peroxyl free radical

Source: Lee at al., (2005); Huang et al., (2005)

6

(b) Single electron transfer (SET) mechanisms:

In SET reaction, antioxidant transfers one electron to the free radical , becoming itself a radical cation. Subsequently, propagation of free radical is

inhibited by HAT mechanism (Rojano et aI., 2008).

ROO- + AH -7

ROO- + ArOH-+ -7 ArO- + ROOH

(2.1)

(2.2)

The ability of antioxidants to retard lipid peroxidation has at least two sides.

First of it is the antioxidative potential which is determined by the antioxidant

composition and their antioxidative properties. Another side is the biological effects

that depend on antioxidant bioavailability among other things. The first is the

subject of food chemistry where the latter is about medico-biological problem

(Roginsky and Lissi, 2005). As such, antioxidants are important to the food

industry besides act as prophylactic agents (Zhang et al., 2006).

2.2.1 Classification of Food Antioxidants

Food antioxidants are classified as (a) primary or chain-breaking antioxidants, (b)

synergists and secondary antioxidants based on their function (Rajalakshmi and

Narasimhan, 1996). Primary antioxidants terminate the free-radical chain reaction

by donating hydrogen or electrons to free radicals and converting them to more

stable products. They may also function by addition in reactions with the lipid

radicals, forming lipid-antioxidant complexes (Rajalakshmi and Narasimhan, 1996).

On the other hand, secondary antioxidants are compounds that retard the

rate of chain initiation by chelating metal ions, scavenging oxygens, decomposing

hydroperoxides to non-radical species, absorbing ultra-violet radiation or

deactivating singlet oxygen (Kormin, 2005; Maisuthisakul et aI., 2007). Compounds

listed under miscellaneous antioxidants such as amino acids function as both

primary antioxidants and synergists. Table 2.2 shows the mechanisms of action

and their corresponding representative compounds of primary and secondary

antioxidants (Rajalakshmi and Narasimhan, 1996).

7

Table 2.2: Classification of food antioxidant Food Antioxidant Group / Mechanism of

action Compounds

Primary antioxidant Phenols gallates, hydroquinone

"Hindered" phenol

Miscellaneous primary antioxidant

BHT,BHA,TBHQ

Trolox-C, anoxomer, ethoxyquin

Secondary / Synergistic Oxygen scavengers Sulfites, ascorbic acid, ascorbyl palmitate antioxidant

Source: Kormin, (2005)

Chelating agents EDTA, polyphosphate, citric acid, lecithin, tartaric acid

Secondary antioxidants Thiodipropionic acid, distearyl ester

Miscellaneous antioxidants Amino acid, spices extract, flavonoids, vitamin A, ~-carotene, tea extract

2.3 Source of Food Antioxidants

2.3.1 Synthetic Antioxidants

Synthetic antioxidants are chemically synthesized (Kormin, 2005) and are not

found in nature. Traditionally, synthetic phenolic compounds, such as butylated

hydroxytoluene (BHT), butylated hydroxyanisole (BHA), tert-butylhydroquinone

(TBHQ) and propyl gallate (PG) are widely used as antioxidants in fat-containing

formulations. The addition of it is required to preserve flavour and colour and to

avoid vitamin destruction. However their harmlessness is at present a controversial

point (Ito et al., 1986; Whysner et al., 1994; Williams et al., 1999).

8

REFERENCES

Abad-Garcia, B., Berrueta, L. A., Marquez, D. M. L., Ferrer, I. c., Gallo, B. and Vicente, F. 2007. Optimization and validation of methodology based on solvent extraction and liquid chromatography for the simultaneous determination of several polyphenolic families in fruit juices. Journal of Chromatography A. 1154: 87-96.

Abdel-Aal, E. M., Young, J. C. Rabalski, 1., 2006. Anthocyanin composition in black, blue, pink, purple, and red cereal grains. Journal of Agricultural and Food Chemistry. 54: 4696-4704.

Abdul-Hamid, A., Raja Sulaiman, R. R., Osman, A. and Saari, N. 2007. Preliminary study of the chemical composition of rice milling fractions stabilized by microwave heating. Journal of Food Composition and Analysis. 20(7): 627-637.

Adom, K. K. and Liu, R. H. 2002. Antioxidant activity of grains. Journal of Agricultural and Food Chemistry. 50: 6182-6187.

Adom, K. K., Sorrells, M. E., Liu, R. H. 2005. Phytochemicals and antioxidant activity of milled fractions of different wheat varieties. Journal of Agricultural and Food Chemistry. 53(6): 2297-2306.

Afanas'ev, I. B., Dorozhko, A. I., Brodskii, A. V., Kotsyuk, V. A. and Potapovitch, A. I. 1989. Chelating and free radical scavenging mechanisms of inhibitory action of rutin and quercetin in lipid peroxidation. Biochemical Pharmalogy. 38: 1763-1769.

Aguilar-Garcia, c., Gavino, G., Baragano-Mosqueda, M., Hevia,P. and Gavino, V. 2007. Correlation of tocopherol, tocotrienol, (-oryzanol and total polyphenol content in rice bran with different antioxidant capacity assays. Food Chemistry. 102: 1228-1232.

Amarasinghe, B. M. W. P. K., Kumarasiri, M. P. M. and Gangodavilage, N. C. 2009. Effect of method of stabilization on aqueous extraction of rice bran oil. Food and Bioproducts Processing. 87: 108-114.

•

~ I

Amarowicz, R., Pegg, R. B., Rahimi-Moghaddam, P., Barl, B. and Weil, J. A. 2004. Free-radical scavenging capacity and antioxidant activity of selected plant species from the Canadian prairies. Food Chemistry. 84: 551-562.

Amin, I., Norazaidah, K. and Hainida, E. 2006. Antioxidant activity and phenolic contenct of raw and blanched Amaranthus species. Food Chemistry. 94: 47-52.

Andrikopoulos, N. K., Brueschweller, H., Felber, H. and Taeschler, C. 1991. HPLC analysis of phenolic antioxidants, tocopherols and triglycerides. Journal of the American Oil Chemist's Society. 68: 359-364.

Angerosa, F., d' Alessandro, N., Konstantinou, P. and Di Giacinto, L. 1995. GC-MS evaluation of phenolic comoounds in virgin olive oil. Journal of Agriculture and Food Chemistry. 43: 1802-1807.

Anil Kumar, H. G., Khatoon, 5., Prabhakar, D.S. and Gopala Krishna, A.G. 2006. Effect of cooking of rice bran on the quality of extracted oil. Journal of Food Lipids. 13(4): 341-353.

Antolovich, M., Prenzler, P., Robards, K. and Ryan, D. 2000. Sample preparation in the determination of phenolic compounds in fruits. The Analyst 125: 989-1009.

Arabshahi-D, 5., Vishalakshi, D. D., Urooj, A., 2007. Evaluation of antioxidant activity of some plant extracts and their heat, pH and storage stability. Food Chemistry. 100: 1100-1105.

Aruoma, O. I. 1998. Free radical, oxidative stress, and antioxidants in human health and disease. Journal of the American Oil Chemists Society. 75: 199-192.

Azizah, A. H., Nik Ruslawati, N. M., and Tee, S. T. 1999. Extraction and characterization of antioxidant from cocoa by-products. Food Chemistry. 64: 199-202.

Azrina, A., Maznah, I. and A. H. Azizah. 2008. Extraction and Determination of Oryzanol in rice bran of mixed herbarium UKMB; AZ 6807: MR 185, AZ 6808: MR 211, AZ6809: MR 29. ASEAN Food Journal. 15(1): 89-96.

64

Balasundram, N., Sundram, K., Samman, S. 2006. Phenolic compounds in plants and agri-industrial by-products: Antioxidant activity, occurrence, and potential uses. Food Chemistry. 99: 191-203.

Barber, S. and Benedito de Barber, C. 1980. Rice bran: Chemistry and technology. In Luh, B. S. (ed.). Rice: Production and Utilization, pp. 791. New York: AVI Publishing Co. Westport.

Bazykina, N. I., Nikolaevskii, A. N., Filippenko, T. A. and Kaloerova, V. G. 2002. Optimization of conditions for the extraction of natural antioxidants from raw plant materials. Pharmaceutical Chemistry Journal. 36(2): 100-103.

Beardsell, D., Francis, J. and Ridley, D. 2002. Health promoting constituents in plant derived edible oils. Journal of Food Lipids. 9: 1-34.

Becker, E. M., Nissen, L. R., Skibsted, L. H. 2004. Antioxidant evaluation protocols: food quality or health effects. European Food Research and Technology. 219: 561-571.

Benzie, I. F. F., and Strain, J. J. 1996. The ferric reducing ability of plasma (FRAP) as a measure of antioxidant power: The FRAP assay. Analytical Biochemistry. 239: 70-76.

Bergman, C. J., Xu, Z. 2003. Genotype and environment effects on tocopherol, tocotrienol and gamma-oryzanol contents of southen U.S. rice. Cereal Chemistry. 80(4): 446-449.

Bersuder, P., Hole, M. and Smith G. 2001. Antioxidants from a heated histidine­glucose model system. Investigating of the copper (II) binding ability. Journal of American Oil Chemical Society. 78: 1079 - 1082.

Bouis, H. E., Chassy, B. M. and Ochanda, J. O. 2003. Genetically modified food crops and their contribution to human nutrition and food quality. Trends in Food Science and Technology. 14: 191-209.

Box, H. C. and Maccubbin, A. E. 1997. Lipid peroxidation and DNA damage. Nutrition. 13: 920-921.

65

Bramley, P. M., Elmadfa, I., Kafatos, A., Kelly, F. J., Manios, Y., Roxborough, H. E., Schuch, W., Sheehy, P. J. A. and WClgner, K. H. 2000. Review vitamin E. Journal of the Science of Food and Agriculture, 80: 913-938.

Brigelius-Flohe, R. and Trabet, M. G. 1999. Vitamin E: function and metabolism. Journal of the Federation of American Societies for Experimental Biology. 13: 1145-1155.

Britz, S. J., Prasad, P. V. V., Moreau, R. A., Allen, L. H., Kremer, D. F. and Boote, K. J. 2007. Influence of growth temperature on the amounts of tocopherols, tocotrienols, and gamma-oryzanol in brown rice. Journal of Agricultural and Food Chemistry. 55: 7559-7565.

Brown, J. E., Khodr, H., Hider, R. C. and Rice-Evans, C. A. 1998. Structural dependence of flavonoid interactions with Cu2+ ions: Implications for their antioxidant properties. Biochemical Journal. 330(3): 1173-1178.

Butsat, S. and Siriamornpun, S. 2009. Antioxidant capacities and phenolic compounds of the husk, bran and endosperm. Food Chemistry. 119(2): 606-613.

Cahoon, E. B., Hall, S. E., Ripp, K. G., Ganzle T. 5., Hitz, W. D. and Coughlan, S. J. 2003. Metabolic redesign of vitamin E biosythesis in plants for tocotrienol production and increased antioxidant content. Nature Biotechnology. 21: 1082-1087.

Carol, L. E. 1990. Functional properties and applications of stabilized rice bran in baked products. Journal of Food Technology. 44: 74-77.

Chan, E. W. c., Lim, Y. Y., Wong, S. K., Lim, K. K., Tan, S. P., Lianto, F. S. and Yong, M. Y. 2009. Effects of different drying methods on the anitioxidant properties of leaves and tea of ginger species. Food Chemistry. 113: 166-172.

Chang, T. and Luh, B. S. 1991. Overview and prospects of rice production. In Luh, B. S. (ed.). Rice Produdion 2nd ed. vol 1, pp. 1-11. Westport: AVI Publishing.

66

Chen, B. H., and Tang, Y. C. 1998. Processing and stability of carotenoid powder from carrot pulp waste. Journal of Agricultural and Food Chemistry. 46: 2312-2318.

Chen, M. H. and Bergman, C. J. 2005. Influence of kernel maturity, milling degree and milling quality on rice bran phytochemical concentrations. Cereal Chemistry. 82: 4-8.

Chirinos, R., Rogez, H., Campos, D., Pedreschi, R., and Larondelle, Y. 2007. Optimization of extraction conditions of antioxidant phenolic compounds from mashua (Tropaeolum tuberosum RUlz & Pavon) tubers. Separation and Purification Technology. SS (2): 217-225.

Choi, Y., Jeong, H. S. and Lee, J. 2007. Antioxidant activity of methanolic extracts from some grains consumed in Korea. Food Chemistry. 103: 130-138.

Choi, Y., Lee, S. M., Chun, J. Lee, H. B. and Lee, J. 2006. Influence of heat treatment on the antioxidant activities and polyphenolic compounds of Shiitake (Lentinus edodes) mushroom. Food Chemistry. 99: 381-387.

Choong, C. T. 2005. Antioxidant Activity and Bioactive Compounds of Sweet Potatoes. Thesis. United States of America: North Carolina State University.

Chotimarkorn, C. and Silalai, N. 2008a. Oxidative stability of fried dough from rice flour containing rice bran powder during storage. Food Science and Technology. 41: 561-568.

Chotimarkorn, C. and Silalai, N. 2008b. Addition of rice bran oil to soybean oil during frying increases the oxidative stability of the fried dough from rice flour during storage. Food Research International. 3: 308-317.

Chotimarkorn, c., Benjakul, S. and Silalai, N. 2008c. Antioxidant components and properties of five long-grained rice bran extracts from commercial available cultivars in Thailand. Food Chemistry. 111: 636-641.

Chu, Y. and Hus, H. 1999. Effects of antioxidants on peanut oil stability. Food Chemistry. 66: 29-34.

67

Cicco, N., Lanorte, M. T., Paraggio, M., Viggiano, M., Lattanzio, V. 2009. A reproducible, rapid and inexpensive Folin-Ciocalteu micro-method in determining phenolics of plant methanol extracts. Microchemical Journal. 91: 107-110.

Contini, M., Baccelloni, 5., Massantini, R., and Anelli, G. 2008. Extraction of natural antioxidants from hazelnut (Corylus ave//ana L.) shell and skin wastes by long maceration at room temperature. Food Chemistry. 110: 659-669.

Coulson, J. M. and Richardson, J. F. 1991. Chemical Engineering, Particle Technology and Separation Processes, Vol 2. New York, USA: Pergamon Press.

Dalla Valle, A. Z., Mignani, 1., Spinardi, A., Galvano, F. and Ciappellano, S. 2007. The antioxidant profile of three different peaches cultivars (Prunus persica) and their short-term effect on antioxidant status in human. European Food Research and Technology. 225(2): 167-172.

Dawidowicz, A. L., Rado, E., Wianowska, D., Mardarowicz, M. and Gawdzik, J. 2008. Application of PLE for the determination of essential oil components from Thymus vulgaris L. Talanta, 76: 878-884.

Decker, E. A. 1998. Antioxidant mechanism. In c.c. Akoh and D.B. Min (eds.). Food Lipids, pp. 397-421. New York: Marcel Dekker.

Decker, E. A. and Hultin, H. O. 1992. Lipid oxidation in muscle foods via redox iron. In A. J. S. Angelo (ed.), Lipid oxidation in food. ACS Symposium Series, vol 500. Washington, DC: American Chemical Society.

Denisov, E. and Khudyakov, 1. 1987. Mechanism of action and reactivities of the free radicals of inhibitors. Chemical Review. 87: 1313-1357.

Devi, R. and Arumughan, C. 2007. Antiradical efficacy of phytochemical extracts from defatted rice bran. Food Chemistry. 45: 2014-2021.

Dewanto, V., Wu, X., Adom, K. K. and Liu, R. H. 2002a. Thermal processing enhances the nutritional value of tomatoes by increasing total antioxidant activity. Journal of Agricultural and Food Chemistry. 50: 3010-3014.

68

Dewanto, V., Wu, X. and Liu R. H. 2002b. Processed sweet corn has higher antioxidant activity. Journal of Agricultural and Food Chemistry. 50: 4959-4964.

Diack, M., and Saska, M. 1994. Separation of vitamin E and y-oryzanols from rice bran by normal-phase chromatography. Journal of American Oil Chemistry Society. 71: 1211-1217.

Dinis, T. C P., Madeira, V. M. C. and Almeida, L. M. 1994. Action of phenolic derivatives (acetaminophen, salicylate, and 5-amino salicylate) as inhibitors of membrane lipid peroxidation and as peroxy radical scavengers. Archives of Biochemistry and Biophysics. 351: 161-169.

Dorman, H. J. D., Peltoketo, A., Hiltunen, R. And Tikkanen, M. J. 2003. Charaterization of the antioxidant properties of deodorized aqueous extracts from selected Lamiaceae Herbs. Food Chemistry. 83: 255-262.

Dutra, R. c., Leite, M. N. and Barbosa, N. R. 2008. Quantification of phenolic constituents and antioxidant activity of Pterodon emarginatus Vogel Seeds. International Journal of Molecular Sciences. 9: 606-614.

Duvernay, W. H., Assad, J. M., Sabliov, C. M., Lima, M. and Xu, Z. 2005. Microwave extraction of antioxidant components from rice bran. Pharmaceutical Engineering. 25: 126-130.

Eberhardt, M. V., Lee, C. Y. and Liu, R. H. 2000. Antioxidant activity of fresh apples. Nature. 405: 903-904.

Eicher, K. 1981. Antoxidative effect of Maillard reaction intermediates. Progress in Food Nutrition and Science. 5: 441-451.

Enochain, R. V., Saunders, R. M., Schultz, W. G., Beagle, E. C. and Crowley, P. R. 1981. Stabilization of rice bran with extruder cookers and recovery of edible oil: A preliminary analysis of operational and financial feasibility. Marketing Research Report No. 1120: USDA.

FAD. 1996. Draft Definiton and Classification of Commodities, W2979.

69

Fardet, A., Rock, E. And Remesy, c. 2008. Is the vitro antioxidant potential of whole-grain cereals and cereal products well reflected in vivo? Journal of Cereal Science. 48: 258-276.

Farhoosh, R. 2005. Antioxidant activity and mechanism of action of butein in linoleic acid. Food Chemistry. 93: 633-639.

Finocchiaro, F., Ferrari, B., Gianinetti, A., DaII'Asta, c., Galaverna, G. and Scazzina, F. 2007. Charaterization of antioxidant compounds of red and white rice and changes in total antioxidant capacity during processing. Molecular Nutrition and Food Research. 51: 1006-1019.

Foti, M. c., Dasquino, C. and Geraci, C. 2004. Electron-transfer reaction of cinnamic acids and their methyl esters with the DPPH radical in alcohol solutions. Journal of Organic Chemistry. 69: 2309-2314.

Frankel, E. N., and Meyer, A. S. 2000. Review. The problems of using one­dimensional methods to evaluate multifunctional food and biological antioxidants. Journal of the Science of Food and Agriculture. 80: 1925-1941.

Franzke, C. and Iwainsky, H. 1954. Antioxidant action of melanoidins. Deutsche Lebensmittel- Rundschau. 580: 251-255.

Gaydou, E. M., Raonizafinimanana, R., and Bianchini, J. P. 1980. Quantitative analysis of fatty acids and sterols in Malagasy rice bran oils. Journal of American Oil Chemistry Society. 57: 141-142.

Geckil, H., Ates, B., Durmaz, G., Erdogan, S. and Yilmaz, 1. 2005. Antioxidant, free radical scavenging and metal chelating characteristics of propolis. American Journal of Biochemistry and Biotechnology. 1(1): 27-31.

Gerhanrdt, A. L. and Gallo, N. B. 1998. Full-fat rice bran and oat bran similarly reduce hypercholesterolemia in humans. Journal of Nutrition. 128: 865-869.

Ghosh, M. 2007. Review on recent trends in rice bran oil processing. Journal of the American Oil Chemists/ Society. 84: 315-324.

70

Godber, J. 5. and Wells, J. H. 1994. Rice bran: As a viable source of high value chemicals. Louisiana Agriculture. 37(2): 13-17.

Godber, J. 5., Juliano, B. o. 2004. Rice Lipids. In E T. Champagne (Ed.), Rice: Chemistry and technology :I'd ed., pp. 163-190. Minnesota: American Association of Cereal Chemists Inc.

Godber, J. 5., Martin, D., Shin, T. 5., Setlhako, G., Tricon, c., and Gervais, M. 1993. Quality parameters important in rice bran for human consumption. Louisiana Agriculture. 36(3): 9-12.

Goffman, F. D., Pinson,S. and Bergman, C. 2003. Genetic diversity for lipid content and fatty acid profile in rice bran. The Journal of the American Oil Chemists' Society. 80: 485-490.

Gorinstein, 5., Vargas, O. J. M., Jaramillo, N. 0., Salas, I. A., Ayala, A. L. M., Arincibia-Avila, P. 2007. The total polyphenols and the antioxidant potentials of some selected cereals and pseudocereals. European Food Research and Technology. 225 (3-4): 321-328.

Goto, M., Minamide, T., Fujii, M., Iwata, T. 1984. Preventive effect of cold shock on chilling injury of Mume (Japense apricot, Prunus mume Sieb. Et Zucc.) fruits in relation to changes of permeability and fatty acid composition of membrane. Journal of Japanese Society for Horticultural Science. 53: 210-218.

Gray, D. A., Clarke, M. J., Baux, c., Bunting, J. P. and Salter, A. M. 2002. Antioxidant activity of oat extracts added to human LDL particles and in free radical trapping assays. Journal of Cereal Science. 36: 209-218.

Halliwell, B. and Gutteridge, J. M. C. 1985. The chemistry of oxygen radicals and toerh oxygen-derived species. In B. Halliwell and J. M. C. Gutteridge (eds.). Free Radicals in Biology and Medicine, pp. 20 -64. New York: Oxford University Press.

Halliwell, B., Gutteridge J.M.C. and Aruoma, o. I. 1987. The deoxyribose method: a simple "test-tube" assay for determination of rate constants for reactions of hydroxyl radicals. Analytical Biochemistry. 165: 215-219.

71

Hargrove, K. L. 1994. Processing and utilization of rice bran in the United States. In Marshall, W. E. and Wadsworth, J. I. (eds). Rice Science and Technology Edition, pp. 380-402. New York: Marcel Dekker.

Hayase, F., Hirashima, F., Okamoto, G. and Kato, H. 1989. Scavenging of active oxygens by melanoidins. Agricultural and Biological Chemistry. 53: 3383-3385.

Hegsted, M. and Windhauser, M. M. 1993. Reducing human heart disease rick with rice bran. Louisiana Agriculture. 36(3): 22-24.

Hegsted, M., Windhauser, M., Lester, S. and Morris, S. 1990. Stabilized rice bran and germ product on hypercholesterolemia. Food Chemistry. News 32(37).

Heinemann, R. J. B., Xu, Z. M., Godber, J. S. and Lanfer-Marquez, U. M. 2008. Tocopherols, tocotrienols and gamma-oryzanol contents in Japonica and Indica subspecies of rice (Oryza sativa L.) cultivated in Brazil. Cereal Chemistry. 85: 243-247.

Heim, K. E., Tagliaferro, A. R. and Bobilya, D. J. 2002. Flavonoids antioxidants: chemistry, metabolism and structure-activity relationships. Journal of Nutritional Biochemistry. 13: 572-584.

Heldman, D. R. and Lund, D. B. 1992. Handbook of Food Engineering. New York: Marcel Dekker.

Hider, R. C., Liu, Z. D. and Khodr, H. H. 2001. Metal chelation of polyphenols. In L. Packer (ed.). Methods in enzymology. Flavonoids and other polyphenols, vol. 335, pp. 190-203. London: Academic Press.

Hippeli, S. and Elstner, E. F. 1999. Transition metal ion-catalysed oxygen activation during pathogenic processes. FEBS Letters. 443 (1): 1-7.

Hodge, D. M., J. M., Delong, Forney, C. F. and Prange, R. K. 1999. Improving the thiobarbituric acid-reactive-substances assay for estimating lipid peroxidation in plant tissues containing anthocyanin and other interfering compounds. Planta. 207: 604-611.

72

Hodge, J. E. 1953. Chemistry of browning in model systems. Journal of Agricultural Food Chemistry. 1: 928-943.

Hodge, D. M., Lester, G. E., Munro, K. D. and Toivonen, P. M. A. 2004. Oxidative stress: importance for postharvest quality. HortScience. 39: 924-929.

Hoffpauir, C. L., Petty, D. H. and Guthrie, J. D. 1947. Germination and free fatty acid in individual cotton seeds. Science. 106(2754): 344-345.

Houston, D. F. 1972. Rice bran and polish. In Houston, D. F. E. (ed.). Rice: Chemistry and Techonology. Minnesota: AACC Publications.

Huang, D., Ou, B., and Prior, R. L. 2005. The chemistry behind antioxidant capacity assays. Journal of Agricultural and Food Chemistry. 53: 1841-1856.

Huang, Y. c., Chang, Y. H. and Shao, Y. Y. 2006. Effects of genotype and treatment on the antioxidant activity of sweet potato in Taiwan. Food Chemistry. 98: 529-538.

Hu, c., Zawistowki, J., Ling, W., Kitts, D. D. 2003. Black rice (Oryza sativa L. indica) pigmented fraction suppresses both reactive oxygen species and nitric oxide in chemical and biological model systems. Journal of Agricultural and Food Chemistry. 51: 5271-5277.

Hultin, H. O. 1994. Oxidation of lipids in seafoods. In F. Shahidi and J.R. Botta (eds.). Seafoods: Chemistry, Processing Technology and Quality, pp. 49-74. UK: Blackie Academic and Professional, Glasgow.

Hundermer, J. K., Nabar, S. P., Shriver, B. J. and Froman, L. P. 1991. Dietary fiber sources lower blood cholesterol in C57BLj6 mice. Journal of Nutrition. 121: 1360-1365.

Hu, W., Wells, J. H., Shin, T. 5., and Godber, J. S. 1996. Comparison of isopropanol and hexane for extraction of vitamin E and oryzanols from stabilized rice bran. Journal of the American Oil Chemists Society. 73: 1653-1656.

73

Ibanez, E., Oca, A., de Murga, G., Lopez-Sebastian, 5., Tabera, J. and Reglero, G. 1999. Supercritical fluid extraction and fractionation of different preprocessed rosemary plants. Journal of Agricultural and Food Chemistry. 47: 1400-1404.

Indyk, H. and Woollard, D. C. 1986. Antioxidant analysis in edible oils and fats by normal-phase high-performance liquid chromatography. Journal of Chromatography. 356: 401-408.

Imahori, Y., Takemura, M., Bai, J. 2008. Chilling-induced oxidative stress and antioxidant responses in mume (Prunus mume) fruit during low temperature storage. PosthalVest Biology and Technology. 49: 54-60.

Inkpen, J. A. and Quackenbush, F. W. 1969. Extractable and bound fatty acids in wheat and wheat products. Cereal Chemistry. 46: 580-587.

Iqbal,S., Bhanger M. I. and Anwar F. 2005. Antioxidant properties and components of some commercially avaible varieties of rice bran in Pakistan. Food Chemistry. 93: 265-272.

Iqbal,S., Bhanger, M. I. and Anwar, F. 2007. Antioxidant properties and components of some commercially available varieties of rice bran in Pakistan. Food Science and Technology. 2: 361-367.

Ismail, A., Marjan, Z. M. and Foong, C. W. 2004. Total antioxidant activity and phenolic content in selected vegetables. Food Chemistry. 87: 581-586.

Ito, N., Hirose, M., Fukushima,S., Tsuda, R., Shirai, T. and Tatematsu, M. 1986. Studies on antioxidants: their carcinogenic and modifying effects on chemical carcinogenesis. Food Chemistry. Toxicol. 24: 1071-1082.

Jimenez-Escrig, A., Rincon, M., Pulido, R. and Saura-Calixto, F. 2001. Guava fruit (Psidium guajava L.) as a new source of antioxidant dietary fiber. Journal of Agricultural and Food Chemistry. 49: 5489-5493.

Juliana, c., Cassu, M., Alamanni, M. C. and Piu, L. 2005. Antioxidant activity of gamma-oryzanol: Mechanism of action and its effect on oxidative stability of pharmaceutical oils. International Journal of Pharmaceutics. 299: 146-154.

74

Juntachote, T., Berghofer, E., Bauer, F., and Siebenhandl, S. 2006. The application of response surface methodology to the production of phenolic extracts of lemon grass, galangal, holy basil and rosemary. International Journal of Food Science and Technology. 41: 121-133.

Ju, Y. -H. and Vali, S. R. 2005. Rice bran oil as a potential residual for biodiesel: a review. Journal of Scientific and Industrial Research. 64: 866-882.

Kahkonen, M. P., Hopia, A. T., Vuorela, H. J., Rauha, J. -P., Pihlaja, K. and Kujala, T. S. 1999. Antioxidant activity of plant extracts containing phenolic compounds. Journal of Agricultural and Food Chemistry. 47: 3954-3962.

Kahlon, T., Saunders, R., Sayre, R., Chow, F., Chin, M., and Betschart, A. 1992. Cholesterol-lowering effects of rice bran and rice bran oil fraction in hypercholesterolemic hamsters. Cereal Chemistry. 69: 485-489.

Kamal-Eldin, A., and Appelqvist, L. A. 1996. The chemistry and antioxidant properties of tocopherols and tocotrienols. Lipids. 31: 813-822.

Kamal-Eldin, A., Go"rgena, 5., Pettersson, J. and Lampi, A. -M. 2000. Normal­phase high-performance liquid chromatography of tocopherols and tocotrienols comparison of different chromatographic columns. Journal of Chromatography A. 881: 217-227.

Kaneko, R. and Tsuchiya, T. 1995. New compound in rice bran and germ oils. Chemistry 49: 4897b.

Kim, J. -5. and Godber, J. S. 200l. Oxidative stability and vitamin E levels increased in restructured beef roast with added rice bran oil. Journal of Food Quality. 24: 17-26.

Kormin, S. 2005. The Effect of Heat ProceSSing on Triterpene Glycosides and Antioxidant Activity of Herbal Pegaga (Centella asiatica L. Urban) Drink. Thesis. University Technology Malaysia.

Krishna, A. G. G., Hemakumar, K. H. and Khatoon, S. 2006. Study on the composition of rice bran oil and its higher free fatty acid value. Journal of the American Oil Chemists' Society. 83: 117-120.

75

Krings, U., EI-saharty, Y. S., EI-Zeany, B. A., Pabel, B. and Berger, R. G. 2000. Antioxidant acitivity of extracts from roasted wheat germ. Food Chemistry. 71: 91-95.

Laguerre, M., Lecomte, J., and Villeneuve, P. 2007. Evaluation of the ability of antioxidants to counteract lipid oxidation: Existing methods, new trends and challenges. Progress in Lipid research. 46: 244-282.

Lai, P., Li, K. Y., Lu, S. and Chen, H. H. 2009. Phytochemicals and antioxidant properties of solvent extracts from Japonica rice bran. Food Chemistry. 117: 538-544.

Lakkakula, N. R., Lima, M. and Walker, T. 2004. Rice bran stabilization and rice bran oil extration using othmic heating. Bioresource Technology. 92: 157-161.

Landbo, A. K. and Meyer, A. S. 2001. Enzyme assisted extraction of antioxidative phenols from blackcurrant juice press residues (Ribers nigrum). Journal of Agricultural and Food Chemistry. 49(7): 3169-3177.

Larrauri, J. A., Ruperez, P. and Saura-Calixto, F. 1997. Effect of drying temperature on the stability of polyphenols and antioxidant activity of red grape pomace peels. Journal of Agricultural and Food Chemistry. 45(4): 1390-1393.

Larrauri, J. A., Sanchez-Moreno, c. and Saura-Calixto, F. 1998. Effect of temperature on the free radical scavenging capacity of extracts from red and white grape pomace peels. Journal of Agricultural and Food Chemistry. 46: 2694-2697.

Larson, R. A. 1995. Plant defenses against oxidative stress. Archives of Insect Biochemistry and Physiology. 29: 175-186.

Lee, J. W., Kim, M. K., Rhee, c., Kim,!. H. and Lee K. W. 2005. Beneficial effects on the unsaponifiable matter from rice bran on oxidative stress in vitro compated with -tocopherol. Journal of the Science of Food and Agriculture. 85: 493-498.

76

Lee, S. c., Kim, J. H., Jeong, S. M., Kim, D. R., Ha, J. U., Nam, K. C. and Ahn, D. U. 2003. Effect of far-infrared radiation on the antioxidant activity of rice hull. Journal of Agriculture and Food Chemistry. 51: 4400-4403.

Lerma-Garda, M. J., Herrero-Martinez, J. M., Simo-Alfonso, E. F., Mendonca, C. R. B. and Ramis-Ramos, G. 2009. Composition, industrial processing and applications of rice bran gamma-oryzanol. Food Chemistry. 115(2): 389-404.

Li, B. B., Smith, B. and Hossain, M. M. 2006. Extraction of phenolics from citrus peels II. Enzyme-assisted extraction method. Separation and Purification Technology. 28: 189-196.

Liang, C. H., Syu, J. L. and Mau, J. L. 2009. Antioxidant properties of solid-state fermented adlay and rice by Phellinus linteus. Food Chemistry. 116: 841-845.

Lilitchan, S., Tangprawat, c., Aryusuk, K., Krisnangkura, 5., Chokmoh, S. and Krisnangkura K. 2008. Partial extraction method for the rapid analysis of total lipids and y-oryzanol contents in rice bran. Food Chemistry. 106: 752-759.

Lim, Y. Y. and Murtijaya, J. 2006. Antioxidant properties of Phyllanthus amarus extracts as affected by different drying methods. L WT-Food Science Technology. 40: 255-260.

Lindley, M. G. 1998. The impacts of food processing on antioxidant in vegetable oils, fruits and vegetables. Trends in Food Science and Technology. 9: 336-340.

Lingnert, H., Vallentin, K., and Erikson, C. E. 1979. Measurement of antioxidative effect in model system. Journal of Food Processing and PreselVation. 3: 87-103.

Liu, R. H. 2004. Potential synergy of phytochemicals in cancer prevention: mechanism of action. Journal of Nutrition. 134: 34795-34855.

Liu, R. H. 2007. Whole grain phytochemicals and health. Journal of Cereal Science. 46(3): 207-219.

77

Liyana-Pathirana, c., and Shahidi, F., 2005. Optimization of extraction of phenolic compounds from wheat using response surface methodology. Food Chemistry. 93: 47-56.

Loeb, J. R. and Mayne, R. Y. 1952 . . Effect of moisture on the microflora and formation of free fatty acids in rice bran. Cereal Chemistry. 29: 163-175.

Luh, B. S. 1980. Rice: Production and Utilization. USA: AVI Publishing Company, INC.

Lurie, S. 1998. Postharvest heat treatments. Postharvest Biology and Technology. 14: 257-269.

Lloyd, B. J., Sienbenmorgen, T. J. And Beers, K. W. 2000. Effects of Commercial Processing on Antioxidants in Rice Bran. Cereal Chemistry. 77(5): 551-555.

Madhavi, D. L. Singhal, R. S. and Kulkarni, P. R. 1996. In D. L. Madhavi, S. S. Deshapande and D. K. Salunkhe (eds.). Technological Aspects of Food Antioxidants in Food Antioxidant-Technological. Toxicological and Health Perspective/ pp. 159-265. New York: Marcel Dekker.

Madhujith, T., and Shahidi, F. 2006. Optimization of the extraction of antioxidative constituents of six barley cultivars and their antioxidant properties. Journal of Agricultural and Food Chemistry. 54(21): 8048-8057.

Maillard, M., -N., Billaud, c., Chow, Y., -N., Ordonaud, C. and Nicolas, J. 2007. Free radical scavenging, inhibition of polyphenoloxidase activity and copper chelating properties of model Maillard systems. LWT. 40: 1434-1444.

Maisuthisakul, P., Suttajit, M., and Pongsawatmanit, R. 2007. Assessment of phenolic content and free radical-scavenging capacity of some Thai indigenous plants. Food Chemistry. 100: 1409-1418.

"Maklumat Perangkaan Tanaman Pertanian Tahunan". http://www.sabah.gov.my/tani/s4 mak pertanianimaklumat pertanian.ht ml. Retrived 20 August 2009

78

Malekian, F., Rao, R. M., Prinyawiwatkul, W., Marshall, W. E., Windhauser, M. and Ahmedna, M. 2000. Lipase and lipoxygenase activity, functionality and nutrient losses in rice bran during storage. Bullentin of Louisiana Agricultural Experiment Station, LSU Agricultural Centre. 870: 1-68.

Manzocco, L., Anese, M., and Nicoli, M. C. 1998. Antioxidant properties of tea extracts as affected by processing. LWT-Food Science and Technology. 31: 694-698.

Martin, D., Godber, J. 5., Setlhako, G., Verma, L. and Wells, J. H. 1993. Optimizing rice bran stabilization by extrusion cooking. Louisiana Agriculture. 36(3): 13-15.

Martinez-Tome, M., MurCia, M. A., Frega, N., Ruggieri,S., Jimenez, A. M., Roses, F. and Parras, P. 2004. Evaluation of antioxidant capacity of cereal brans. Journal of Agricultural and Food Chemistry. 53(6): 2297-2306.

Matthaus, B. 2002. Antioxidant activity of extracts obtained from residues of different oilseeds. Journal of Agricultural and Food Chemistry. 50: 3444-3452.

Mattson, F. H. and Grundy, S. M. 1985. Comparison effects of dietary saturated, monounsaturated, and polyunsaturated fatty acids on plasma lipids and lipoproteins in man. Journal of Lipid Research. 26: 194-199.

Mau, J. -L., Chang, c., -N., Huang,S., -J. and Chen, c., -CO 2004. Antioxidant properties of methanolic extracts from Grifolo frondosa, Morchella esculenta and Termitomyces albuminosus mycelia. Food Chemistry. 87: 111-118.

Matz, S. A. 1991. Chemistry and technology of cereals. In The Chemistry and Technology of Cereals as Food and Feed, pp 215-257. New York: Springer.

McCaskill, D. R. and Zhang, F. 1999. Use of rice bran oil in foods. Food Technology. 53(2): 50-52.

McDonalds, 5., Prenzler, P. D., Antolovich, M. and Robards, K. 2001. Phenolic content and antioxidant activity of olive extracts. Food Chemistry. 73: 73-84.

79

Mikkelsen, D. S. and de Datta, S. K. 1991. Rice culture. In Luh, B. S. (ed.). Rice Production, pp. 103-120. Westport: AVI Publishing.

Milardovic, S., Ivekovic, D. and Grabaric, B. S. 2005. A novel amperometric method for antioxidant activity determination using DPPH free radical. Bioelectrochemistry. 68(2): 175-180.

Miller, A. and Engel, K. H. Content of gamma-oryzanol and composition of steryl ferulates in brown rice (Oryza sativa L.) of European origin. Journal of Agricultural and Food Chemistry. 54: 8127-8133.

Moldenhauer, K. A., Champagne, E. T., McCaskill, D. R. and Guraya, H. 2003. Functional products from rice. In G. Mazza (Ed.)., Functional foods, pp. 71-89. Lancaster, Basel, Switzerland: Technomic Publishing Co., Inc ..

Montedoro, G., Servili, M., Baldioli, M. and Miniati, E. 1992. Simple and hydrolysable phenolic compounds in virgin olive oil. Their extraction, separation and quantitative and semiquantitative evaluation by HPLC. Journal of Agriculture and Food Chemistry. 40: 1571-1576.

Morales, F. J. and Babbel, M. B. 2002. Antiradical efficiency of Maillard reaction mixtures in a hydrophilic media. Journal of Agricultural and Food Chemistry. 50: 2788-2792.

Moure, A., Cruz, J. M., Franco, D., Dominguez, J. M., Sineiro, J. and Dominguez, H. 2001. Natural antioxidants from residual sources. Food Chemistry. 72: 145-171.

Mukhopadhyay, S., Luthria, D. L. and Robbins R. J. 2006. Optimization of extraction process for phenolic acids from cohosh (Cimicifuga racemosa) by pressurezed liquid extraction. Journal of the Science of Food and Agriculture. 86: 156-162.

Murcia, M. A., Jimenez, A., M., Martinez-Tome, M. 2009. Vegetables antioxidant losses during industrial processing and refrigerated storage. Food Research International. 42: 1046-1052.

80

(

Nam, S. H., Choi, S. P., Kang, M. Y., Kozukue, N. and Friedman, M. 2005. Antioxidative, antimutagenic, and anticarcinogenic activities of rice bran extracts in chemical and cell assays. Journal of Agricultural and Food Chemistry. 53: 816-822.

Narayana, T., Kaimal, B., Vail, S. R., Surya, B. V., Rao K. and Charkraabarti, P. P. 2002. Origin of problems encountered in rice bran oil processing. European Journal Lipid Science Technology. 104: 203-211.

Nasirullah, Krishnamurthy, M. N. and Nagaraja, K. V. 1989. Effect of Stabilization on the Quality Characteristics of Rice Bran Oil. Journal of American Oil Chemists' Society. 66: 5.

Nicoli, M. c., Anese, M., Parpinel, M. T. and Franceschi, S. 1999. Influence of processing on the antioxidant properties of fruits and vegetables. Trends in Food Science and Technology. 10: 94-100.

Nicoli, M. c., Anese, M., Parpinel, M. T., Franceschi, S. and Lerici, C. R. 1997. Loss and/or formation of antioxidants during food processing and storage. Cancer Letter. 114: 71-74.

Nicolosi, R. J., Ausman, L. M. and Hegsted, D. M. 1991. Rice bran oil lowers serum total and low density lipoprotein cholesterol and apo B levels in non human promates. Atherosclerosis. 88: 133-142.

Nicolosi, R. J., Rogers, E. J., Ausman, L. M., and Orthoefer, F. T. 1994. Rice bran oil and its health benefits. In W.E. Marshall and J.I. Wadsworth, (eds). Rice Science and Technology. New York: Marcel Dekker.

Norton, R. A. 1995. Quantitation of steryl ferulate and p-coumarate esters from corn and rice. Lipids. 30: 269-274.

Nanua, J. N., McGregor, J. U. and Godber, J. S. 2000. Influence of high-oryzanol rice bran oil on the oxidative stability of whole milk powder. Journal of Dairy Science. 83: 2426-2431.

Nystrom, L., Makinen, M., Lampi, A.-M. and Orthoefer, F. T. 1994. Rice bran oil and its health benefits. In W. E. Marshal and J. I. Wadsworth (eds.). Rice Science and Tecnhology, pp. 350-421. New York: Marcel Dekker.

81

Olsson, M. E., Ekvall, E., Gustavsson, J., Nilsson, K. E., Pillald, J. and Sjoholm, 1. 2004. Antioxidants, low molecular weight carbohydrates, and total antioxidant capacity in strawberries (Fragaria ananassa): Effects of cultivar, ripening and storage. Journal of Agricultural and Food Chemistry. 52(9): 2490-2498.

Onyeneho, S. N. and Hettiarachchy, N. S. 1992. Antioxidant activity of durum wheat bran. Journal of Agricultural and Food Chemistry. 49: 1496-1500.

Orthoefer, F. T. and Eastman, J. 2004. Rice bran and oil. In Champagne, E. T. (ed.). Rice: Chemistry and technology, 3rd ed., pp. 569-593. Minnesota: American Association of Cereal Chemists Inc.

Oufnac, D. S., Xu, Z., Sun, T., Sabliov, c., Prinyawiwatkul, W. and Godber, J. S. 2007. Extraction of antioxidants from wheat bran using conventional solvent and microwave-assisted methods. Cereal Chemistry. 84: 125-129.

Packer, L. 1995. Vitamin E: beyond antioxidant function. American Journal of Clinical Nutrition. 62(6): 1501.

Parr, A. J., Bolwell, G. P. 2000. Phenols in the plant and in man. The potential for possible nutritional enhancement of the diet by modifying the phenols content or profile. Journal of the Sciences Food and Agriculture. 80: 985-1012.

Patel, M. and Naik, S. N. 2004. Gamma-Oryzanol from rice bran oil - A review. Journal of Scientific and Industrial Research. 63: 569-578.

Pekkarinen, S. S., Stockmann, H., Schwarz, K., Heinoneen, M. And Hopia, A. 1. 1999. Antioxidant activity and partitioning of phenolic acids in bulk and emulsified methyllinoleate. Journal of Agricultural and Food Chemistry. 47: 3036-3043.

Peleg, H., Naim, M., Rouseff, R. L. and Zehavi, U. 1991. Distribution of bound and free polyphenolic acids in oranges (Citrus sinensis) and grapefruit (Citrus paradise). Journal of the Science Food and Agriculture. 57: 417-426.

82

Pellegrini, N. Serafini, M., Colombi, B., Del Rio, D., Salvatore, S., Bianchi, M. and et al. 2003. Total antioxidant capacity of plant foods, beverages and oils consumed in Italy assessed by three different in vitro assays. Journal of Nutrition. 133: 2812-2819.

Perez-Jimenez, J., and Saura-Calixto, F. 2005. Literature data may underestimate the actual antioxidant capacity of cereals. Journal of Agricultural and Food Chemistry. 53: 5036-5040.

Perez-Jimenez, J., Arranz, S., Tabernero M., DIaz-Rubio, M. E., Serrano, J., Goni, I., Saura-Calixto F. 2008. Updated methodology to determine antioxidant capacity in plant foods, oils and beverages: Extraction, measurement and expression of results. Food Research International. 41: 274-285.

Pietta, P. G. 2000. Flavonoids as antioxidants. Journal of Natural Products. 63: 1035-1042.

Pinelo, M., Rubilar, M., Jerez, M., Sineiro, J., and Nunez, M. J. 2005. Effect of solvent, temperature, and solvent-to-solid ratio on the total phenolic content and antiradical activity of extracts from different components of grape pomace. Journal of Agricultural and Food Chemistry. 53: 2111-2117.

Pirisi, F. M., Angioni, A., Cabras, P., Garau, V. L., di Teulada, M. T. S., dos Santos, M. K. and Bandino, G. 1997. Phenolic compounds in virgin olive oils. Low­wavelength quantitative determination of complex phenols by high­performance liquid chromatography under isocratic elution. Journal of Chromatography A. 768: 207-201.

Pokorny, J. and Schmidt, S. 2001. Evaluation of drying technologies of physical quality and antioxidants in asparagus (Asparagus officinalis. L.). Lebensmittel-Wissenschaft und-Technologies. 36(5): 507-516.

Potter, N. N. and Hotchkiss, J. H. 1998. Cold Preservation and Processing. In Food Science. Fifth Edision, pp. 163-167. New York: Aspen Publisher.

Pourali, 0., Asghari, F. S. and Yoshida, H. 2009. Simultaneous rice bran oil stabilization and extraction using sub-critical water medium. Journal of Food Engineering. 95: 510-516.

83

Prabhakar, J. V. 1987. Stabilization of bran. In Hand Book on Rice Bran. Solvent Extractors Association of India: India.

Prabhakar, J. V. and Venkatesh, K. V. L. 1986. A simple chemical method for stabilization of rice bran. Journal of American Oil Chemists' SOciety. 63: 644-646.

Prior, R. L., Wu, X., and Schaich, K. 2005. Standardized methods for the determination of antioxidant capacity and phenolics in foods and dietary supplements. Journal of Agricultural and Food Chemistry. 53(10): 4290-4302.

Prokopov, T. and Tanchev, S. 2006. Method of Food Preservation. In McElhantton, A. and Marshall R. J. (eds.). Food Safety: A Practical and Case Study Approach, pp. 3-25. New York: Springer Science and Business.

Pryor, W. A. 1991. The antioxidant nutrients and disease prevention - What do we know and what we need to find out. American Journal of Clinical Nutrition. 53: 391-393.

Psotova, J., Lasovsky, J. and Vicar, J. 2003. Metal-chelating properties, electrochemical behavior, scavenging and cytoprotective activities of six natural phenolics. Bio medical Papers. 147(2): 147-153.

Pulido, R., Bravo, L., and Saura-Calixto, F. 2000. Antioxidant activity of dietary polyphenols as determined by modified ferric reducing/antioxidant power assay. Journal of Agriculture and Food Chemistry. 48: 3396-3402.

Qureshi, A. A., Qureshi, N., and Wright, J. J. K. 1991. Lowering of serum cholesterol in hypercholesterolemic humans by tocotrienols (pamvitee). American Journal of Clinical Nutrition. 53: 1021-1026.

Raghuram, T. c., and Rukmini, C. 1995. Nutritional and biochemical aspects of the hypolipidemic action of rice bran oil: A review. Journal of American College of Nutrition. 10: 593-601.

84

Rajalakshmi, D. and Narasimhan, S. 1996. Food Antioxidants: sources and methods of evaluation. In Madhavi, D. L., Deshpande, S. S. and Salunkhe, D. K. (eds.). Food Antioxidants: Technological, Toxicological, and Health Perspectives, pp. 65-73. New York: Marcel Dekker.

Ramezanzadeh, F. M., Rao, R. M., Prinyawiwatkul, W., Marshall, W. E. and Windhauser, M. 2000. Effects of microwave heating, packaging, and storage temperature on fatty acids and proximate compositions in rice bran. Journal Agricultural and Food Chemistry. 48(2): 464-467.

Ramenzanzadeh, F. M., Rao, R. M., Windhauser, M., Prinyawiwatkul, W. and Marshall W. E. 1999. Prevention of Oxidative Rancidity in Rice Bran during storage. Journal of Agricultural Food Chemistry. 47: 2997-3000.

Renuka Devi, R. and Arumughan, C. 2007. Phtochemical characterization of defatted rice bran and optimization of a process for their extraction and enrichment. Bioresource Technology. 98:3037-3043.

Rhee, J. S. and Yoon, N. H. 1984. Stabilization of rice bran by microwave energy. Korean Journal of Food Science Technology. 16(1): 113.

Rice-Evans, C. A., Miller, N. J. and Paganga, G. 1996. Structure-antioxidant activity relationships of flavonoids and phenolic acids. Free Radical Biology and Medicine. 20: 933-956.

Robbins, R. J. 2003. Phenolic acids in foods: An overview of analytical methodology. Journal of Agricultural and Food Chemistry. 51: 2866-2887.

Rogers, E. l, Rice, S.M., Nicolosi, R. J., Carpenter, D. R., McClelland, C. A. and Romanczyk Jr., L. J. 1993. Identification and quantitation of y-oryzanol components and simultaneous assessment of tocopherols in rice bran oil. Journal of the American Oil Chemists' Society. 70(3): 301-307.

Roginsky, V. and Lissi, E. A. 2005. Review of methods to determine chain-breaking antioxidant activity in food. Food Chemistry. 92: 235-254.

Rohrer, C. A. and Sieben morgen, T. J. 2004. Nutraceutical concentrations within the bran of various rice kernel thickness fractions. Biosystems Engineering. 88: 453-460.

85

ROjano, B., Saez, J.~ Schinella, G., Quija~o, J., Velez, E, Gil, A. and Notario, R. 2008. .Expenm~ntal .and theoretIcal determination of the antioxidant propertIes of Isoespmtanol (2-isopropyl-3,6-dimethoxy-5-methylphenol). Journal of Molecular Structure. 877: 1-6.

Romani, A., Pinelli, P., Galardi, c., Sani, G., Cimato, A. and Heim/er, D. 2002. Polypheno/s in greenhouse and open-air-grown lettuce. Food Chemistry. 79: 337-342.

Rouanet, J. -M., Laurent, C. and Besancon, P. 1993. Rice bran and wheat bran: selective effect on plasma and liver cholesterol in high cholesterol fed rats. Food Chemistry. 47: 67-71.

Roy, M. K., Takenaka, M., Isobe, S. and Tsushida, T. 2007. Antioxidant potential, antiproliferative activities and phenolic content in water-soluble fractions of some commonly consumed vegetables: Effects of thermal treatment. Food Chemistty. 103: 106-114.

Ruth, S. M., Shaker, E. S. and Morrissey P. A. 2001. Influence of methanolic extracts of soybean seeds and soybean oil on lipid oxidation in linseed oil. Food Chemistry. 75: 177-184.

Saint-Cricq de Gau/ejac, N., Provost, C. and Vivas, N. 1999. Comparative study of polyphenol scavenging activities assessed by different methods. Journal of Agriculatural and Food Chemistry. 47: 425-431.

Sa/a, J. M. and Lafuente, M. T. 2004. Antioxidant enzymes activities and rind staining in 'Naveline' oranges as affected by storage relative humidity and ethylene conditioning. Postharvest Biology and Technology. 31: 277-285.

Santoso, J., Yoshie-Stark, Y. and Suzuki, T. 2004. Anti-oxidant activity of methanol extracts from Indonesian seaweeds in an oil emulsion model. Fisheries Science. 70: 183-188.

Sathishkumar R., Lakshmi, P. T. V. and Annamalai, A. 2009. Effect of drying treatm'ent on the content of antioxidants in Enicostemma littorale b/ume. Research Journal of Medicinal Plant 3(3): 93-101.

86

Saunders, R. M. 1985. Rice bran: composition and potential food sources. Food Research International. 13: 465-495.

Saunders, R. M. 1990. The properties of rice bran as a food stuff. Cereal Food World 35: 632-636.

Saura-Calixto, F. and Goni, I 2006. Antioxidant capacity of Spanish Mediterranean diet. Food Chemistry. 94(3): 442-447.

Sayre, R. N. 1988. Rice bran as a source of edible oil and higher value chemicals. In Proceedings of the 7? annual meeting of American Association of Cereal ChemiSts, pp. 1-11. San Diego: CA.

Scalbert, A., Manach, c., Morand and Remesy, c. 2005. Dietary polyphenols and the prevention of diseases. Critical Reviews in Food Science and Nutrition. 45: 287-306.

Schieber, A., Stintzing, F. C. and Carle, R. 2001. By-products of plant food processing as a source of functional compounds - recent developments. Trends in Food Science and Technology. 12: 401-413.

Schwartz, H., O/liJainen, V., Piironen, V., Lampi, A. 2008. Tocopherol, tocotrienol and plant sterol contents of vegetable oils and industrial fats. Journal of Food Composition and Analysis. 21: 152-161.

Seetharamaiah, G. S. and Chandrasekhara, N. 1989. Studies on hypocholesterolemic activity of rice bran oil. Atherosclerosis. 78: 219-223.

Shahidi, F. 1997. Natural antioxidants: An overview. In Shahidi, F. (Ed.), Natural antioxidant chemistry, health effects and applications, pp. 1-10. Champaign, IL, USA: AOCS Press.

Sheabar, F. Z., and Neeman, I. 1988. Separation and concentration of natural antioxidants from the rape of olives. Journal of the American Oil Chemists' Society. 65: 990-993.

Sherwin, E. R. 1990. Antioxidants. In A.L. Branen, P. M. Davidson & S. Salminen. Food antioxidants. New York: Marcel Dekker.

87

Shewfelt, R. L. and Purvis, A. C. 1995. Towards a comprehensive model for lipid peroxidation in plant tissue disorder. HortScience. 30: 213-218.

Shigeoka, S., Ishikawa, T., Tamoi, M., Miyagawa, Y., Takeda, T., Yabuta, Y., Yoshimura, K. 2002. Regulation and function of ascorbate peroxidase isoenzymes. Journal of Experimental Botany. 53: 1305-1319.

Shimada, K., Fujikawa, K., Yahara, K. and Nagamura, T. 1992. Antioxidative properties of xanthan on the autoxidation of soybean oil in cyclodextrin emulsion. Journal of Agricultural and Food Chemistry. 40: 945-948.

Shin, T. S. and Godber, J. S. 1993. Improved high-performance liquid chromatography of vitamin E vitamers on normal-phase columns. Journal of the American Oil Chemists/ SOCiety. 70: 1289- 1291.

Shin, T., Godber, J. S., Martin, D. E. and Wells, J. H. 1997. Hydrolitic stability and changes in E vitamers and oryzanol of extruded rice bran during storage. Journal of Food Science. 62: 704-708.

Shui, G. H. and Leong, L. P. 2002. Residues from star fruit as valuable source for functional food ingredients and antioxidant nutraceuticals. Food Chemistry. 97: 277-284.

Siddhuraju, P., Mohan, P. S. and Becker, K. 2002. Studies on the antioxidant acitivity of Indian laburnum (Cassia Fistula L.): a preliminary assessment of crude extracts from stem bark, leaves, flowers and fruit pulp. Food Chemistry. 79: 61-67.

Sies, H. 1997. Oxidative stress: oxidants and antioxidants. Experimant physiology. 82: 291-295.

Sies, H., Stahl, W. and Sevanian, A. 2005. Nutritional, dietary and postprandial oxidative stress. Journal of Nutrition. 135: 969-972.

Siger, A., Nogala-Kalucka, M., Lampart-Szczapa E. 2008. The content and antioxidant activity of phenolic compounds in cold-pressed plant oils. Journal of Food Lipids. 15: 137-149.

88

Singleton, V. L., Orthofer, R., and Lamela-Raventos, R. M. 1999. Analysis of total phenols and other oxidation substrates and antioxidant by means of Folin­Ciocalteu reagent. Method in Enzymology. 299: 152-178

Smith, c., Halliwell, B. and Aruoma, O. I. 1992. Protection by albumin against the pro-oxidant actions of phenolic dietary components. Food and Chemical Toxicology. 30: 483-489.

Soares, J. R., Dins, T. C. P., Cunha, A. P. and Ameida L. M. (1997). Antioxidative activity of some extracts of Thymus Zygis. Free Radical Research. 26: 469-478.

Spigno, G., Tramelli, L., and De Faveri, D. M. 2007a. Effects of extraction time, temperature and solvent on concentration and antioxidant activity of grape marc phenolics. Journal of Food Engineering. 81: 200-208.

Spigno, G. and De Faveri, D. M. 2007b. Antioxidant from grape stalks and marc: Influence of extraction procedure on yield, purity and antioxidant power of the extracts. Journal of Food Engineering. 78: 793-801.

Srivastava, A., Akoh, C. c., Yi, W., Fisher, J. and Krewer, G. 2007. Effect of storage conditions on the biological activity of phenolic compounds of blueberry extract packed in glass bottles. Journal of Agricultural and Food Chemistry. 55: 2705-2713.

Suzuki, Y., Yasui, T., Matsukura, U. and Terao, J. 1996. Oxidative stability of bran lipids from rice variety [Oryza sativa (L.)] lacking lipoxygenase-3 in seeds. Journal of Agriculture Food Chemistry. 44: 3479-3488.

Szydlowska-Czerniak, A., Dianoczki, c., Recseg, K., Karlovits, G. and Szlyk, E. 2008. Determination of antioxidant capacities of vegetable oils by ferric-ion spectrophotometric methods. Talanta. 76: 899-905.

Tao, J., Rao, R. M. and Liuzzo, J. 1993. Microwave heating for rice bran stabilization. Journal of Microwave Power and Electromagnetic Energy. 28: 156-164.

89

Tiwari, U. and Cummins, E. 2009. Nutritional importance and effect of processing on tocols in cereals. Trends in Food Science and Technology. 20(11-12): 511-520.

Toivonen, P. M. A. 2003. Postharvest treatments to control oxidative stress in fruits and vegetables. In Hodges, D. M. (ed.). PosthalVest Oxidative Stress in Horticultural Crops, pp. 225-267. New York: Haworth.

Tomaino, A., Cimino, F., Zimbalatti, V, Venuti, V., Sulfaro, V. and De Pasquale, A. 2005. Influence of heating on antioxidant activity and chemical composition of some spice essential oils. Food Chemistry. 89: 549-554.

Toar, R. K. and Savage, G. P. 2006. Effect of semi-drying on the antioxidant components of tomatoes. Food Chemistry. 94: 90-97.

Tuberoso, C. 1. G., Kowalczyk, A., Sarritzu, E. and Cabras, P. 2007. Determination of antioxidant compounds and antioxidant activity in commercial oilseeds for food use. Food Chemistry. 103(4): 1494-1501.

Turkmen, N., Sari, F., and Velioglu, Y. S. 2006. Effects of extraction solvents on concentration and antioxidant activity of black and black mate tea polyphenols determined by ferrous tartrate and Folin-Ciocalteu methods. Food Chemistry. 99: 835-841.

Von Gadow, A., Joubert, E. and Hansmann, C. F. 1997. Comparison of the antioxidant activity of aspalathin with that of the plant phenols of rooibos tea (Asalathus linearis), tocopherol, BHT and BHA. Journal of Agricultural and Food Chemistry. 45: 632-638.

Vinter, H. 1995. The handling of fats and oils in the food industry. Food Technology International Europe. 133-136.

Visser, M. N., Zock, P. 1., Meijer, G. W. and Katan, M. B. 2000. Effect of plant sterols from rice bran oil and triterpene alcohols from sheanut oil on serum lipoprotein concentrations in humans. American Journal of Clinical Nutrition. 72: 1510-1515.

Wanasundara, U. N. and Shahidi, F. 1998. Antioxidant and pro-oxidant activity of green tea extracts in marine oils. Food Chemistry. 63: 335-342.

90

Wang, J., Sun, B. G., Cao, Y. P., Tian, Y., and Li, X. H. 2008. Optimization of ultrasound-assisted extraction of phenolic compounds from wheat bran. Food Chemistry. 106: 804-810.

Wells, J. H. 1993. Utilization of rice bran and oil in human diets. Louisiana Agriculture. 36(3): 5-8.

Westphal,S., Gekeler, G. H., Dierkes, J., Wieland, H., Luley, C. 2002. A free fatty acid tolerance test identifies patients with coronary artery disease among individuals with a low conventional coronary risk profile. Heart Vessels. 16: 79-85.

White, P. l, and Xing, Y. 1997. Antioxidants from cereals and legumes. In Shahidi, F. (ed.)/ Natural antioxidants/ chemistry, health effects and applications, pp. 25-63. Champaign, IL, USA: AOCS Press.

Whysner, L., Wang, C. X., Zang, E., Iatropoulos, M. J. and Williams, G. M. 1994. Dose response of promotion by butylated hydroxyanisole in chemically initiated tumours of the rat forestomach. Food Chemistry. Toxicol. 32: 215-222.

Wijewickreme, A. N., Kitt, D. D. and Durance, T. D. 1997. Reaction conditions influence the elementary composition and metal chelating affinity of nondialyzable model Maillard reaction products. Journal of Agricultural and Food Chemistry. 45: 4577-4583.

Willcox, J. K., Ash, S. L., and Catignani, G. L. 2004. Antioxidants and prevention of chronic disease. Critical Reviews in Food Science and Nutrition. 44: 275-295

Williams, G. M., Latropoulos, M., J., and Whysner, J. 1999. Safety assessment to butylated hydroxyanisol and butylated hydroxytoluence as antioxidant food additives. Food and Chemical Toxicology. 37: 1027-1038.

Wismer, W. V. 2003. Low temperature as a causative agent of oxidative stress in postharvest crops. In Hodges, D. M. (ed.). PosthalVest Oxidative Stress in Horticultural Crops, pp. 55-65. New York: Haworth.

91

Wu, C. H., Murthy, H. N., Hann, E. J., Lee, H. L. and Paek, K. Y. 2008. Efficient extraction of caffeic acid derivatives from adventitious roots of Echinacea purpurea. Czech Journal of Food Science. 26 (4): 254-258.

Xu, Z. and Godber, J. S. 1999. Purification and identification of components of y­oryzanol in rice branoil. Journal of Agricultural Food Chemistry. 47: 2724-2728.

Xu, Z., Hua, N., and Godber, J. S. 2001. Antioxidant activity of tocopherols, tocotrienols and y-oryzanol components from rice bran against cholesterol oxidation accelerated by 2,2'-azobis (2-methylpropionamidine) dihydrochloride. Journal of Agricultural and Food Chemistry. 49: 2077-2081.

Yanishlieva-Maslarova, N. V. 2001. Inhibiting oxidation. In Pokorny, J., Yanishlieva, N. and Gordon M. (eds). Antioxidants in Food: Practical Applications, pp. 22-70. Cambridge: Woodhead Publishing Limited/CRC Press.

Yen, G. C. and Hsieh, P. P. 1995. Antioxidative activity and scavenging effects on active oxygen of xylose-lysine Maillard reaction products. Journal of the Science of Food and Agriculture. 67: 415-420.

Yen, G. -c. and Wu, J.-Y. 1999. Antioxidant and radical scavenging properties of extracts from Ganoderma tsugae. Food Chemistry. 65: 375-379.

Yeo, H., and Shibamoto, T. 1991. Effect of moisture content on the Maillard browing model system upon microwave irradiation. Journal of Agricultural Food Chemistry. 39: 1860-1862.

Yildirim, A., Mavi, A. and Kara, A. A. 2001. Determination of antioxidant and antimicrobial activities of Rumex crispus L. extracts. Journal of Agricultural and Food Chemistry. 49: 4083-4089.

Yomauchi, R., Tatsumi, Y., Asano, M., Kato, K. and Ueno, Y. 1988. Effect of metal salts and fructose on the autoxidation of methyl linoleate in emulsions. Agricultural and Biological Chemistry. 52(3): 849-850.

Yong, Y. S. 2007. Determination of synthetic phenolic antioxidants in food items using HPLC and total antioxidants using FIA Approaches. Degree of Master Science Thesis. University Sciences Malaysia.

92

Yoshida, H., Hirooka, N. and Kajimoto, G. 1991. Microwave heating effect on relative stability of tocopherols in oils. Journal of Food Science. 56: 1042-1046.

Yoshie, A., Kanda, A., Nakamura, T., Igusa, H. and Hara S. 2009. Comparison of "1-oryzanol contents in crude rice bran oils from different sources by various determination methods. Journal of Oleo Science. 58: 511-518.

Yoshimura, Y., lijima, T., Watanable, T. and Nakazawa, H. 1997. Antioxidative effect of Maillard reaction products using glucose-glycine model system. Journal of Agricultural and Food Chemistry. 45: 4106-4109.

Yoshino, G., Kazumi, T., and Amano, M. 1989. Effects of y-oryzanol and probucol on hyperlipidemia. Current Theapeutic Research. 45: 975-982.

Youssef, D. and EI-Adawi, H. 2006. Study on grape seeds extraction and optimization: An approach. Journal of Applied Sciences. 6(14): 2944-2947.

Zandi, P. and Gordon, M. H. 1999. Antioxidant activity of extracts from old tea leaves. Food Chemistry. 64: 285-288.

Zhang, D. and Hamauzu, Y. 2004. Phenolics, ascorbic acid, carotenoids and antioxidant activity of broccoli and their changes during conventional and microwave cooking. Food Chemistry. 88: 503-509.

Zhang, H., Chen, F., Wang, X. and Yao, H., -yo 2006. Evaluation of antioxidant activity of parsley (Petroselinum crispum) essential oil and identification of its antioxidant constituents. Food Research International. 39: 833-839.

Zhao, G. R., Xiang, Z. J., Ye, T. X., Yuan, Y. J. and Guo, Z. X. 2006. Antioxidant activities of Salvia miltiorrhiza and Panax notoginseng. Food Chemistry. 99(4): 767 - 774.

Zigoneanu, 1. G., Williams, L., Xu, Z. and Sabliov, C. M. 2008. Determination of antioxidant components in rice bran oil extracted by microwave-assisted method. Bioresource Technology. 99: 4910-4918.

93

Zullaikah, S., Lai, c., -c., Vali, S. R., Ju, Y. -H. 2005. A two-step aCid-catalysed process for the production of biodiesel from rice bran oil. Bioresource Technology. 96: 1889-1896.

Zuo, Y., Chen, H. and Deng, Y. 2002. Simultaneous determination of catechins, caffeine and gallic acids in green, Dolong, black and pu-erh tea using HPLC with a photodiode array detector. Talanta. 57: 307-316.

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