Fruit and Cereal
Bioactives
Sources, Chemistry, and Applications


Fruit and Cereal
Bioactives
Sources, Chemistry, and Applications

Edited by

Özlem Tokus¸og˘lu 
Clifford Hall III

Boca Raton London New York

CRC Press is an imprint of the
Taylor & Francis Group, an informa business


CRC Press
Taylor & Francis Group
6000 Broken Sound Parkway NW, Suite 300
Boca Raton, FL 33487-2742
© 2011 by Taylor and Francis Group, LLC
CRC Press is an imprint of Taylor & Francis Group, an Informa business
No claim to original U.S. Government works
Printed in the United States of America on acid-free paper
10 9 8 7 6 5 4 3 2 1
International Standard Book Number: 978-1-4398-0665-4 (Hardback)

This book contains information obtained from authentic and highly regarded sources. Reasonable efforts have been made to
publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of all materials
or the consequences of their use. The authors and publishers have attempted to trace the copyright holders of all material reproduced in this publication and apologize to copyright holders if permission to publish in this form has not been obtained. If any
copyright material has not been acknowledged please write and let us know so we may rectify in any future reprint.
Except as permitted under U.S. Copyright Law, no part of this book may be reprinted, reproduced, transmitted, or utilized in any
form by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying, microfilming,
and recording, or in any information storage or retrieval system, without written permission from the publishers.
For permission to photocopy or use material electronically from this work, please access www.copyright.com ( or contact the Copyright Clearance Center, Inc. (CCC), 222 Rosewood Drive, Danvers, MA 01923, 978-750-8400.
CCC is a not-for-profit organization that provides licenses and registration for a variety of users. For organizations that have been
granted a photocopy license by the CCC, a separate system of payment has been arranged.
Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation without intent to infringe.
Library of Congress Cataloging-in-Publication Data
Fruit and cereal bioactives : sources, chemistry, and applications / edited by Ozlem Tokusoglu, Clifford Hall
III.
p. ; cm.
Includes bibliographical references and index.
Summary: “Presenting up-to-date data in an easy-to-use format, this comprehensive overview of
the chemistry of bioactive components of fruits and cereals addresses the role of these compounds in
determining taste, flavor, and color, as well as recent claims of anticarginogenic, antimutagenic, and
antioxidant capabilities. It provides detailed information on both beneficial bioactives such as phenolics,
flavonoids, tocols, carotenoids, phytosterols, and avenanthramides and toxicant compounds including
mycotoxins; aflatoxins, ocratoxin A, patulin, citrinin, cyclopiazonic acid, fumonisin, and zearalenon. A
valuable resource for current knowledge and further research, it offers critical reviews, recent research, case
studies, and references”--Provided by publisher.
ISBN 978-1-4398-0665-4 (hardcover : alkaline paper)
1. Fruit--Composition. 2. Grain--Composition. 3. Phytochemicals--Physiological effect. I. Tokusoglu,
Ozlem, editor. II. Hall, Clifford, III, editor.
[DNLM: 1. Fruit--chemistry. 2. Cereals--chemistry. 3. Dietary Supplements. 4. Phytotherapy. 5. Plant
Extracts--therapeutic use. WB 430]
QK865.F78 2011

664’.8--dc22
Visit the Taylor & Francis Web site at

and the CRC Press Web site at


2010044816


To my mother, retired teacher Özden Tokuşoğlu & my father, retired senior colonel
Armağan Tokuşoğlu, for their great emotional support and cordial encouragements.

Özlem Tokus¸ og˘lu


Contents
Preface....................................................................................................................................................... ix
Editors........................................................................................................................................................ xi
Contributors.............................................................................................................................................xiii

Part I  Introduction
1. Introductıon to Bioactives in Fruits and Cereals........................................................................... 3
Özlem Tokuşoğlu and Clifford Hall III
2. Health Promoting Effects of Cereal and Cereal Products............................................................ 9
Joseph M. Awika

Part I I Chemistry and Mechanisms of Beneficial
Bioactives in Fruits and Cereals
3. Phytochemicals in Cereals, Pseudocereals, and Pulses............................................................... 21
Clifford Hall III and Bin Zhao

4. Phenolic and Beneficial Bioactives in Drupe Fruits..................................................................... 83
Özlem Tokuşoğlu
5. Bioactive Phytochemicals in Pome Fruits................................................................................... 107
Özlem Tokuşoğlu
6. Phytochemicals in Citrus and Tropical Fruit............................................................................ 123
Mehmet Çağlar Tülbek
7. Phytochemical Bioactives in Berries............................................................................................143
Özlem Tokuşoğlu and Gary Stoner
8. Phenolic Bioactives in Grapes and Grape-Based Products.......................................................171
Violeta Ivanova and Marina Stefova
9. Nut Bioactives: Phytochemicals and Lipid-Based Components
of Almonds, Hazelnuts, Peanuts, Pistachios, and Walnuts........................................................185
Biagio Fallico, Gabriele Ballistreri, Elena Arena, and Özlem Tokuşoğlu
10. Nut Bioactives: Phytochemicals and Lipid-Based Components
of Brazil Nuts, Cashews, Macadamias, Pecans, and Pine Nuts.................................................213
Biagio Fallico, Gabriele Ballistreri, Elena Arena, and Özlem Tokuşoğlu
11. Bioactive Lipids in Cereals and Cereal Products...................................................................... 229
Ali A. Moazzami, Anna-Maija Lampi, and Afaf Kamal-Eldin
vii


viii

Contents

Part II I  Mycotoxic Bioactives of Fruits and Cereals
12. Mycotoxic Bioactives in Cereals and Cereal-Based Foods........................................................ 253
Anuradha Vegi
13. Control Assessments and Possible Inactivation Mechanisms
on Mycotoxin Bioactives of Fruits and Cereals.......................................................................... 273

Faruk T. Bozoğlu and Özlem Tokuşoğlu
14. Control of Mycotoxin Bioactives in Nuts: Farm to Fork............................................................291
Mohammad Moradi Ghahderijani and Hossein Hokmabadi

Part I V Functionality, Processing, Characterization, and
Applications of Fruit and Cereal Bioactives
15. Isolation Characterization of Bioactive Compounds in Fruits and Cereals............................319
Xiaoke Hu and Zhimin Xu
16. Effect of Bioactive Components on Dough Rheology, Baking, and Extrusion....................... 337
Joseph M. Awika
17. Impacts of Food and Microbial Processing on the Bioactive
Phenolics of Olive Fruit Products................................................................................................ 347
Moktar Hamdi
18. Antioxidant Activity/Capacity Assay Methods Applied to Fruit and Cereals.........................361
Reşat Apak, Esma Tütem, Mustafa Özyürek, and Kubilay Güçlü
19. Supercritical Fluid Extraction of Bioactive Compounds from Cereals................................... 385
Jose L. Martinez and Deepak Tapriyal
20. Analytical Methodology for Characterization of Grape and Wine Phenolic Bioactives....... 409
Marina Stefova and Violeta Ivanova
21. High Pressure Processing Technology on Bioactives in Fruits and Cereals........................... 429
Özlem Tokuşoğlu and Christopher Doona
Index....................................................................................................................................................... 443


Preface
Interest in bioactive compounds of fruit and cereals has reached a new high in recent years. The scientific and commercial attention devoted to fruit and cereal bioactives has been accentuated even further
by efficiency reports regarding the beneficial and toxic health effects of such compounds. The beneficial bioactives of many fruit and cereals have been declared to possess anticarcinogenic, antimutagenic
effects in test animals. Recently, the strong antioxidant capacities of many edible fruits and cereals have
been revealed. These many bioactive compounds are responsible for several important characteristics
of fruit and cereals: taste, flavor, color alteration, and antioxidant activity. Natural toxicant bioactives as

mycotoxins have also been detected in specific fruits and cereals.
The specific focus for Fruit and Cereal Bioactives is on the chemistry of beneficial and nutritional
bioactives (phytochemicals such as phenolics, flavonoids, tocols, carotenoids, phytosterols, avenanthramides, alkylresorcinols, some essential fatty acids) and toxicant bioactives (mycotoxins, aflatoxins,
ocratoxin A, etc.) from sources such as pome, stone, and berry fruits, citrus fruits, tropical fruits and
nuts, various cereals (and pseudocereals), pulses (e.g., legumes and edible beans), and so on. Overall, this
book is a comprehensive and detailed reference guide to both major natural beneficial phytochemical
bioactives and mycotoxic bioactives in edible fruits and cereals covering all the latest research from a
wide range of experts.
This book is intended for senior undergraduate and graduate students, academicians, and those in
government and the fruit and cereal industry. It provides a practical reference for a wide range of experts:
fruit and cereal scientists, chemists, biochemists, nutritionists, fruit and cereal processors, government
officials, commercial organizations, and other people who need to be aware of the main issues concerning bioactives.
Each chapter reviews dietary sources, occurrences, chemical properties, desirable and undesirable
health effects, antioxidant activity, evidentiary findings, as well as toxicity of the above-mentioned
bioactives and has been individually highlighted based on the fruit and cereal type. Fruit and Cereal
Bioactives presents unique, up-to-date, and unified data of fruit and cereal chemistry from a biochemical
standpoint.

Özlem Tokus¸ og˘lu

ix


Editors
Özlem Tokus¸ og˘lu, who was born in İzmir, Turkey, completed her bachelor (1992) and master
(1996) degrees at EGE University from the Department of Chemistry and completed her doctorate at
EGE University from the Department of Food Engineering (2001). She worked as a research assistant
and Dr. Assistant at EGE University from 1993 to 2001. She was the research assistant at the Food
Science and Nutrition Department at the University of Florida–Gainesville during 1999–2000.
Dr. Tokuşoğlu has been an assistant professor at Celal Bayar University, Manisa, Turkey and is currently working there in the Department of Food Engineering. She is focusing on food quality control,

food chemistry, food safety, and food processing technologies on traditional foods and beverages. Her
specific study areas are phenolics, phytochemicals, bioactive antioxidative components, bioactive lipids,
and their determinations by instrumental techniques, their effects on food and beverages quality, and the
novel food processing effects on their levels.
Dr. Tokuşoğlu performed academic research studies and presentations at Geneva, Switzerland in 1997;
Gainesville, Florida in 1999; Anaheim–Los Angeles, California in 2002; Sarawak, Malaysia in 2002;
Chicago, Illinois in 2003; Katowice-Szczyrk, Poland in 2005; Ghent, Belgium in 2005; Madrid, Spain
in 2006; New Orleans, Louisiana in 2008; Athens, Greece in 2008; Anaheim–Los Angeles, California
in 2009; and Skopje, the Republic of Macedonia in 2009; Chicago, Illinois in 2010; Munich, Germany
in 2010. She was also a visiting professor at the School of Food Science, Washington State University,
Pullman, in the state of Washington for one month during 2010.
Dr. Tokuşoğlu has professional affiliations at the Institute of Food Technologists (IFT) and the
American Oil Chemists’ Society (AOCS) in the United States and has a professional responsibility with
the Turkey National Olive and Olive Oil Council (UZZK) as a research and consultative board member
and as a Turkish Lipid Group (YABITED) founder administrative board member and consultative board
member in the European Federation for Science and Technology (Euro Fed Lipid). Dr. Tokuşoğlu has
78 ­international studies containing 25 papers published in peer-reviewed international journals covered
by the Science Citation Index (SIC) and 11 papers published in peer-reviewed international index covered journals, 42 presentations (as orals and posters) presented at the international congress and other
organizations. She has advised two masters’ students to completion. Dr. Tokuşoğlu has several editorial
assignments in international index covered journals.
Clifford Hall III completed his bachelor degree in 1988 at the University of Wisconsin–River Falls;
his masters (1991) and doctoral (1996) degrees at the University of Nebraska–Lincoln in the area of
food science and technology. He completed a postdoctoral experience at the University of Arkansas in
Fayetteville. Dr. Hall is currently an associate professor in the Department of Cereal and Food Sciences
in the School of Food Systems at North Dakota State University (NDSU). He is the associate director
of the Great Plains Institute of Food Safety and food science coordinator for the Food Science program
at NDSU.
Much of his research deals with lipid oxidation and antioxidant chemistry, stability of phytochemicals
in food processing, and utilization of nontraditional ingredients in food systems. The stability of flaxseed
bioactives and antioxidant activity of raisins has been his major focus recently, including the evaluation

of flaxseed lignan stability in extruded bean snacks. He has published his research in 28 peer-reviewed
international journals, and 12 proceedings, and has published 10 book chapters. His research has created
60 oral and poster presentations at the American Oil Chemists’ Society, Institute of Food Technologists,
International Society of Nutraceutical and Functional Foods, and AACC International annual meetings.
He has advised five PhD and two masters’ students to completion and currently advises two PhD and three
masters’ students. He has also mentored 28 undergraduate researchers and has served on 26 graduate
student committees. Professionally, Clifford has been most active in the AOCS and AACC International.
xi


xii

Editors

He served as the secretary/treasurer, 2003; vice chairperson, 2004; and chairperson, 2005–2007 for the
Lipid Oxidation and Quality Division of the American Oil Chemists’ Society. He served as the chair of
the Best Paper Competition Committee for the Lipid Oxidation and Quality Division, 2003–2006. He
has also served as the chairperson of the Education Division for AACC International, 2007–2009 and
on the AACC International Foundation as a board member, 2008 to the present; and chair, 2009. He has
also served as an associate editor from 1998 to 2006 and senior associate editor from 2006 to the present
for the Journal of the American Oil Chemists’ Society. In addition, he is an ad hoc reviewer for Food
Chemistry, Journal of Food Science, and Journal of Agricultural and Food Chemistry.


Contributors
Reşat Apak
Department of Chemistry
Istanbul University
İstanbul, Turkey


Kubilay Güçlü
Department of Chemistry
Istanbul University
İstanbul, Turkey

Elena Arena
Dipartimento di OrtoFloroArboricoltura e
Tecnologie Agroalimentari (DOFATA)
Sez. Tecnologie AgroAlimentari
Università degli Studi di Catania
Catania, Italy

Clifford Hall III
School of Food Systems
North Dakota State University
Fargo, North Dakota

Joseph M. Awika
Soil and Crop Science Department
Texas A&M University
College Station, Texas
Gabriele Ballistreri
Dipartimento di OrtoFloroArboricoltura e
Tecnologie Agroalimentari (DOFATA)
Sez. Tecnologie AgroAlimentari
Università degli Studi di Catania
Catania, Italy

Moktar Hamdi
National Institute of Applied Sciences

and Technology
University of 7th November at Carthage
Laboratory of Microbial Ecology and
Technology
Tunis, Tunisia
Hossein Hokmabadi
Department of Horticulture
Pistachio Research Institute of Iran
Rafsanjan, Iran

Faruk T. Bozoğlu
Department of Food Engineering
Engineering Faculty
Middle East Technical University
Ankara, Turkey

Xiaoke Hu
Department of Chemistry
Louisiana State University
Baton Rouge, Louisiana

Christopher Doona
U.S. Army – Natick Soldier Research
Development and Engineering Center
DoD Combat Feeding Directorate
Natick, Massachusetts

Violeta Ivanova
Institute of Chemistry
Faculty of Natural Sciences and Mathematics

Ss Cyril and Methodius University
Skopje, Republic of Macedonia

Biagio Fallico
Dipartimento di OrtoFloroArboricoltura e
Tecnologie Agroalimentari (DOFATA)
Sez. Tecnologie AgroAlimentari
Università degli Studi di Catania
Catania, Italy

Afaf Kamal-Eldin
Department of Food Science
Swedish University of Agricultural
Sciences
Uppsala, Sweden

Mohammad Moradi Ghahderijani
Department of Plant Protection
Pistachio Research Institute of Iran
Rafsanjan, Iran

Anna-Maija Lampi
Department of Chemistry and Applied
Microbiology
University of Helsinki
Helsinki, Finland
xiii


xiv

Jose L. Martinez
Thar Process, Inc.
Pittsburgh, Pennsylvania

Contributors
Özlem Tokuşoğlu
Department of Food Engineering
Celal Bayar University
Manisa, Turkey

Ali A. Moazzami
Department of Food Science
Swedish University of Agricultural
Sciences
Uppsala, Sweden

Mehmet Çağlar Tülbek
Northern Crops Institute
North Dakota State University
Fargo, North Dakota

Mustafa Özyürek
Department of Chemistry
Istanbul University
İstanbul, Turkey

Esma Tütem
Department of Chemistry
Istanbul University
İstanbul, Turkey


Marina Stefova
Institute of Chemistry
Faculty of Natural Sciences and Mathematics
Ss Cyril and Methodius University
Skopje, Republic of Macedonia

Anuradha Vegi
Department of Veterinary and
Microbiological Sciences
North Dakota State University
Fargo, North Dakota

Gary Stoner
Department of Internal Medicine
The Ohio State University
Columbus, Ohio

Zhimin Xu
Department of Food Science
Louisiana State University Agriculture Center
Baton Rouge, Louisiana

Deepak Tapriyal
Thar Process, Inc.
Pittsburgh, Pennsylvania

Bin Zhao
Kraft Foods, Inc.
East Hanover, New Jersey



Part I

Introduction



1
Introduction to Bioactives in Fruits and Cereals
Özlem Tokus¸ og˘lu and Clifford Hall III
Contents
Phytochemicals in Fruit and Cereals........................................................................................................... 3
Phenolics in Fruit and Cereals............................................................................................................... 3
Carotenoids in Fruit and Cereals........................................................................................................... 5
Functional Lipids and Lipid Soluble Constituents................................................................................ 5
Mycotoxic Bioactives in Fruits and Cereals............................................................................................... 7
Concluding Remarks................................................................................................................................... 7
References................................................................................................................................................... 7
Fruit and cereal bioactives are classified as phytochemicals and toxicant secondary metabolites.
Phytochemicals containing polyphenols, carotenoids, and functional lipids are naturally derived substances that have health-promoting, and/or nutraceutical and medicinal proper while mycotoxigenic bioactives are toxic substances that are secondary metabolites synthesized by toxigenic fungal species. A
wide variety of mycotoxins are produced by various fungi, often a single fungal species can synthesize
more than one type of mycotoxic bioactive under optimal conditions.
Interest in the bioactive compounds of fruit and cereals has reached a new high in recent years.
Especially, the scientific and commercial attention in fruit and cereal bioactives have been accentuated
by efficiency reports regarding both beneficial and toxical health effects of such compounds.
According to the National Institutes of Health (NIH), bioactive food phytochemicals including polyphenols, carotenoids, and functional lipids are “constituents in foods or dietary supplements, other
than those needed to meet basic human nutritional needs, that are responsible for changes in health
status.” Major sources of these bioactive food components are plants, especially fruits, vegetables, and
cereals. But major sources of both phytochemicals and mycotoxins are fruits, nuts, and more major

in cereals.
In this book context, a brief description of the chemistry, sources, and applications of the abovementioned major bioactives in fruits and cereals.

Phytochemicals in Fruit and Cereals
Phenolics in Fruit and Cereals
As the name suggests, phytochemicals working together with chemical nutrients found in fruits, cereals,
and nuts may help slow the aging process and reduce the risk of many diseases, including cancer, heart
disease, stroke, high blood pressure, cataracts, osteoporosis, and urinary tract infections (Meskin et al.
2003; Omaye et al. 2000).
Polyphenols occur as plant secondary metabolites. Their ubiquitous presence in plants and plant
foods, favors animal consumption and accumulation in tissues. Polyphenols are widely distributed
in the plant kingdom and represent an abundant antioxidant component of the human diet (Ho, Rafi
and Ghai, 2007). Interest in the possible health benefits of polyphenols has increased due to the
3


4

Fruit and Cereal Bioactives: Sources, Chemistry, and Applications

corresponding antioxidant capacities (Gharras, 2009). Recent evidences show that there is a great
interest to anticarcinogenic effects of polyphenolic compounds, as well as the potential to prevent
cardiovascular and cerebrovascular diseases (Cheynier 2005).
Polyphenols divide into several subgroups including flavonoids, hydroxybenzoic and hydroxycinnamic
acids, lignans, stilbens, tannins, and coumarins that have specific physiological and biogical effects
(Andersen and Markham 2006; Meskin et al. 2003; Tokuşoğlu 2001; Figure 1.1).
Flavonoids are a chemically defined family of polyphenols that includes several thousand compounds. The flavonoids have a basic structure (Figure 1.2), and several subclasses of flavonoids are
characterized by a substitution pattern in the B- and C-rings. The main subclasses of flavonoids include
flavan-3-ols, flavonols, flavones, flavanones, isoflavones, anthocyanidins, anthocyanins, flavononols,
and chalcons (Figure 1.3) that are distributed in plants and food of plant origin (Crozier, Jaganath, and

Clifford 2006).
Flavonoids in the circulation may protect against cardiovascular disease through their interaction with
low-density lipoprotein (LDL). Biochemical and clinical studies in both humans and experimental animals have suggested that oxidized low-density lipoprotein (oLDL) has its atherogenic action through the
formation of lipid hydroperoxides and the products derived therefrom. The in vivo antioxidant status of
the LDL particles and the plasma are thus important determinants of the susceptibility of LDL to lipid
peroxidation (Hertog et al. 1993).
Many of the phytochemicals and some vitamins (vitamin E, tocopherol) have antioxidant activity in
vitro, which has led to the use of the general term “antioxidants.”
Phenolic compounds

Coumarins

Flavonoids
Flavons
Phenolic acids
Isoflavons
Hydroxybenzoic acids
Flavonols
Hydroxycinnamiz acids
Flavanols
Flavanones
Anthocyanidins
Anthocyanins
Flavononols
Chalcons

Lignans

Stilbens


Sesamol
Sesamin
Sesamolin
Sesamolinol

Resveratrol
Piceatannol
Piceid
Pinosylvin
Rhapontisin
Tamoxiphen
Derivative
Phytoalexins

Tannins
Hydrolyzed
Condensed

Figure 1.1  Family of phenolic compounds. (From Andersen, Q. M., and Markham, K. R., Flavonoids. Chemistry,
Biochemistry, and Applications, CRC Press, Taylor & Francis, Boca Raton, FL, 2006; Meskin, M. S., Bidlack W. R.,
Davies, A. J., Lewis, D. S., and R. K. Randolph, Phytochemicals: Mechanisms of Action. CRC Press, Boca Raton, FL,
2003; Tokuşoğlu, Ö., The Determination of the Major Phenolic Compounds (Flavanols, Flavonols, Tannins and Aroma
Properties of Black Teas, PhD Thesis, Department of Food Engineering, Bornova, Izmir, Turkey: Ege University, 2001).)

3
4

2
8
7


B
O

A

C

5

4

6

5
6
3

Figure 1.2  Chemical structure of flavonoids.


5

Introduction to Bioactives in Fruits and Cereals
Flavonoids

Chalcons
Flavons
Apigenin
Luteloin

Baikalein
Krysin
Diosmin
Genkvain
Izorhoifolin
Rhoifolin
Tektokirisin

Isoflavons
Daidzein
Genistein
Biokenin A
Formononetin
Glisitein
Daidzin
Genistin
Glisitin
6 -O-Asetildaidzin
6 -O-Asetilgenistin
6 -O-Asetilglisitin
6 -OMalonildaidzin
6 -OMalonilgenistin
6 -OMalonilglisitin

Flavonols
Quercetin
Kaempferol
Miricetin
Quercitrin
Isoquercitrin

Rhamnetin
Isorhamnetin
kaempferid
Rutin
Astragalin
Hiperosid

Flavan-3-ols
(+)–Catechin
(–)–Epicatechin
(–)–Epicatechingallate
(–)–Epigallocatechin
(–)–Epigallocatechingallate

Flavanons
Hesperetin
Hesperitin
Naringenin
Naringin
Narirutin
Didimin
Eriositrin
Eriodiktiol
Neoriositrin
Neohesperitin
Izosakuranetin
Pinosembrin
Ponsirin
Prunin


Flavononols
(Dihydroflavonols)
Anthocyanidins
Cyanidin
Malvinidin
Delfinidin
Pelargonidin
Petunidin
Peonidin

Anthocyanins
Grape extract

Figure 1.3  Flavonoid family in food plants. (Adopted from Tokuşoğlu, Ö., The Determination of the Major Phenolic
Compounds (Flavanols, Flavonols, Tannins and Aroma Properties of Black Teas, PhD Thesis, Department of Food
Engineering, Bornova, Izmir, Turkey: Ege University, 2001; Merken, H. M., and Beecher, G. R., J. Agric. Food Chem.,
48(3), 579–95, 2000; Beecher, G. R., Antioxidant Food Supplements in Human Health, Academic Press, New York, 1999;
Fennema, O. R., Food Chemistry, Marcel Dekker, New York, 681–96, 1996; Vinson, J. A., Dabbagh, Y. A., Serry, M. M.,
and Jang, J., J. Agric. Food Chem., 43, 2800–2802, 1995.)

Carotenoids in Fruit and Cereals
Carotenoids (Figure 1.4), a group of lipid-soluble compounds responsible for yellow, orange, red, and
violet colors of various fruits and cereals products, are one of the most important groups of natural pigments, owing to their wide distribution, structural diversity, and numerous biological functions (Astorg
1997; Fraser and Bramley 2004).
The provitamin A activity of some carotenoid bioactives, recently, have demonstrated to be effective
in preventing chronic diseases such as cardiovascular disease and skin cancer. Carotenoid bioactives
are classified into four groups: carotenoid hydrocarbons, carotenoid alcohols (xanthophylls), carotenoid
ketons, carotenoid acids.
Hydrocarbon carotenoids are known as carotenes, and the oxygenated derivatives are termed xanthophylls (Astorg 1997; Fraser and Bramley 2004; Lee and Schwartz 2005)


Functional Lipids and Lipid Soluble Constituents
There has been a great interest concerning functional lipids in cereals due to their promotion for health
and preventing diseases. Fatty acids play a central role in growth and development through their roles
in membrane lipids, as ligands for receptors and transcription factors that regulate gene expression, as a
precursor for eicosanoids, in cellular communication, and through direct interactions with proteins.
The main fatty acids in cereals are the saturated fatty acids, palmitic (16:0) and stearic (18:0), the
monounsaturated fatty acid oleic acid (18:1), and the diunsaturated fatty acid inoleic acid (18:2) existing
with smaller amounts of other fatty acids. These fatty acids are mainly assembled in glycerolipids; that
is, triacylglycerols (TAG) and variable amounts of phospholipids (PL), glycolipids (GL), in sterol esters
(SE), and waxes (or policosanols) in the different cereal grains.
Lipid soluble vitamins tocopherols and amphiphilic lipids alkylresorcinols, and terpen alcohol compounds are also important bioactive constituents in cereal grains (Figure 1.5). Cereal lipids have high
levels of tocotrienols that coexist with tocopherols, which are the biologically most active antioxidants


6

Fruit and Cereal Bioactives: Sources, Chemistry, and Applications

Lycopene
BCO

15

BCO-2
10′
9′

15′
all-trans-β-carotene


α-carotene
OH

HO

Lutein

HO

β-cryptoxanthin

H 3C

CH3

HO

CH3

H 3C

CH3

CH3

CH3

CH3

OH


H3C CH3

Zeaxanthine
Figure 1.4  Major carotenoids. (Ross, C. A. and Harrison, E. H., Handbook of Vitamins, Taylor & Francis Group, Boca
Raton, FL, 1–39, 2007.)

R1
HO

H

R2

H

H

H

O
Tocopherols

R1

HO

H

Trematol


HO

H

Fernenol

HO
R2

O

H

Tocotrienols

HO

OH

H

H

H

Isoarborinol

HO


H

H

Sorghumol
R2

R1
HO

n=13-23

H

H

H

H

H

H

Alkyresorcinols

HO

HO
Simiarenol

Triterpen alcohols
-Amyrin R1= methyl, R2 = hydrogen
-Amyrin R1= hydrogen, R2 = methyl

Figure 1.5  Some lipid soluble constituents and cereal grains.


Introduction to Bioactives in Fruits and Cereals

7

(Peterson 2004). Alkylresorcinols have been shown to have bioactivities in vitro and in vivo experiments.
They increase the γ-tocopherol level in rat liver and lung by possibly inhibiting γ-tocopherol metabolism
(Ross, Kamal-Eldin, and Aman 2004). Sterols and sterol-based constituents, terpenoids play a role in traditional herbal remedies and it is reported they show antibacterial, cholesterol-lowering, antiatherogenic,
and anticarcinogenic effects. Phytosterols appear not only to play an important role in the regulation of
cardiovascular disease but also to exhibit anticancer properties (Jones & AbuMweis, 2009).
Those beneficial bioactives of many fruits and cereals have been declared to possess anticarcinogenic
and antimutagenic effects in test animals. Recently, it has also been detected in the strong antioxidant
capacities of many edible fruits and cereals.

Mycotoxic Bioactives in Fruits and Cereals
Mycotoxigenic bioactives are toxic substances that are produced by the secondary metabolism of various
fungal species (Ho, Rafi and Ghai, 2007). Various studies have been reported about their high toxicity
and the possible risk for consumer health. Fungal spoilage of cereals and mycotoxic bioactive production
is most important.
It has been shown that the presence of fungi on fruits is not necessarily associated with mycotoxin
(aflatoxins, ochratoxin A, patulin, citrinin, T2, etc.) contamination. The mycotoxin formation depends
more on endogenous and environmental factors than fungal growth does (Andersen and Thrane 2006).
The studies indicated that Alternaria, and Fusarium in fruit and cereals may pose a mycotoxin
risk. During spoilage of cherries and apples, Penicillum expansum is known to produce patulin. Both

Alternaria and Fusarium are able to produce additional mycotoxic bioactives in moldy fruit samples:
alternariols and aurofusarin.
Penicillum verrucosum is known to produce Ochratoxin A in many cereals. Fusarium is able to produce zearalenone in addition to Ochratoxin A from P.verrucosum in moldy cereals. Aspergillus ochraceus, A.niger, and A.carbonarious produce Ochratoxin A in dried fruits such as raisins and currants
(Iamanaka et al. 2006).

Concluding Remarks
Fruit and Cereal Bioactives are comprised of the specific focus on the chemistry of beneficial and
nutritional bioactives (phytochemicals such as phenolics, flavonoids, tocols, carotenoids, phytosterols,
avenanthramides, alkylresorcinols, and some essential fatty acids) and toxicant biactives (mycotoxins; aflatoxins, ocratoxin A, patulin, citrinin, cyclopiazonic acid, T-2, fumonisin, deoksinivalenol, and
zearalenon) from the sources of selected fleshy fruits including temperate fruits (pome, stone, and berry
fruits), citrus and tropical fruits, nuts, and from various cereals (and pseudocereals), pulses (e.g., legumes
and edible beans).
Each chapter reviews dietary sources, occurrences, chemical properties, desirable and undesirable
health effects, antioxidant activity, evidentiary findings, applications as well as toxicity of the abovementioned bioactives and have been individually highlighted based on the fruit and cereal type. Fruit
and Cereal Bioactives present a unique and unified data to the fruit and cereal chemistry from a biochemical standpoint.

References
Andersen, B., and Thrane, U. 2006. Food-borne fungi in fruit and cereals and their production of mycotoxins.
In Advances in Food Mycology. Vol. 571, 137–52. Berlin: Springer-Verlag.
Andersen, Q. M., and Markham, K. R. 2006. Flavonoids. Chemistry, Biochemistry, and Applications. Boca
Raton, FL: CRC Press, Taylor & Francis.
Astorg, P. 1997. Food carotenoids and cancer prevention: An overview of current research. Trends Food Sci
Tech 8:406–13.


8

Fruit and Cereal Bioactives: Sources, Chemistry, and Applications

Beecher, G. R. 1999. Flavonoids in foods. In Antioxidant Food Supplements in Human Health, eds. L. Packer,

M. Hiramatsu, and T. Yoshikawa. New York: Academic Press.
Cheynier, V. 2005. Polyphenols in foods are more complex than often thought. Am. J. Clin. Nutr. 81 (Suppl):
223–9.
Crozier, A., Jaganath, I. B., and Clifford, M. N. 2006. Phenols, polyphenols and tannins: An overview. In
Plant Secondary Metabolites, eds. A. Crozier, M. N. Clifford, and H. Ashihara, 1–24. Oxford: Blackwell
Publishing, Ltd.
Fennema, O. R. 1996. Flavonoids. In Food Chemistry. 3rd ed., 681–96. New York: Marcel Dekker.
Fraser, P. D., and Bramley, P. M. 2004. The biosynthesis and nutritional uses of carotenoids. Progress in Lipid
Research 43: 228–65.
Gharras, H. E. 2009. Polyphenols: Food sources, properties and applications—A review. Int J Food Sci and
Technol. 44: 2512–8.
Hertog, M. G. L., Feskens, E. J. M., Hollma, P. C. H., Katan, M. B., and Kromhout, D. 1993. Dietary antioxidant flavonoids and risk of coronary heart disease. The Zutphen Elderly Study. Lancet 342:1007–11.
Ho, C. T., Rafi, M. M., and Ghai, G. 2007. Bioactive Substances: Nutraceuticals and Toxicants. In Fennema's
Food Chemistry, 4th, eds. Srinivasan Damodaran, Kirk L. Parkin, Owen R. Fennema, CRC Press, Taylor
& Francis, Boca Raton, FL, USA ISBN: 9780824723453, ISBN 10: 0824723457. 1160.
Iamanaka, B. T., Taniwaki, M. H., Vicente, E., and Menezes, H. C. 2006. Fungi producing ochratoxin in dried
fruits. In Advances in Food Mycology. Vol. 571, 181–88. Berlin: Springer-Verlag.
Jones, P. J., and AbuMweis, S. S. 2009. Phytosterols as functional food ingredients: Linkages to cardiovascular
disease and cancer. Curr Opin Clin Nutr Metab Care 12 (2): 147–51.
Lee, J. H., and Schwartz, S. J. 2005. Analysis of carotenoids and chlorophylls in foods. In Methods of Analysis
of Food Components and Additives, 179–98. New York: Taylor & Francis Group.
Merken, H. M., and Beecher, G. R. 2000. Measurement of food flavonoids by high performance liquid chromatography: A review. J Agric Food Chem 48 (3): 579–95.
Meskin, M. S., Bidlack W. R., Davies, A. J., Lewis, D. S., and R. K. Randolph. 2003. Phytochemicals:
Mechanisms of Action. Boca Raton, FL: CRC Press.
Omaye, S. T., Bidlack, W. R., Meskin, M. S., and D. K. W. Topham. 2000. Phytochemicals as Bioactive Agents.
Lancaster, PA: Technomic Pub.
Peterson, D. M. 2004. Barley tocols—Effects of milling, malting, and mashing. Cereal Chem 71 (1): 42–4.
Ross, C. A., and Harrison, E. H. 2007. Vitamin A: Nutritional aspects of retinoids and carotenoids. In Handbook
of Vitamins. 4th ed., eds. J. Zempleni, R. B. Rucker, D. B. McCormick, and J. W. Suttie, 1–39. Boca
Raton, FL: Taylor & Francis Group.

Ross, A. B., Kamal-Eldin, A., and Aman, P. 2004. Dietary alkylresorcinols: Absorption, bioactivities, and possible use as biomarkers of whole-grain wheat- and rye-rich foods. Nutr Rev 62 (3): 81–95.
Tokuşoğlu, Ö. 2001. The Determination of the Major Phenolic Compounds (Flavanols, Flavonols, Tannins and
Aroma Properties of Black Teas. PhD Thesis. Department of Food Engineering, Bornova, Izmir, Turkey:
Ege University.
Vinson, J. A., Dabbagh, Y. A., Serry, M. M., and Jang, J. 1995. Plant flavonoids, especially tea flavonols,
are powerful antioxidants using an in vitro oxidation model for heart disease. J Agric Food Chem 43:
2800–2.


2
Health Promoting Effects of Cereal
and Cereal Products
Joseph M. Awika
Contents
Introduction................................................................................................................................................. 9
Cereal Consumption and Cancer.............................................................................................................. 10
Possible Mechanisms of Cereal Grains in Chemoprevention...............................................................11
Dietary Fiber Related Mechanisms..................................................................................................11
Antioxidant Related Mechanisms....................................................................................................11
Phytoestrogen Related Mechanisms............................................................................................... 12
Mediation of Glucose Response..................................................................................................... 12
Cereal Grain Consumption and Cardiovascular Disease.......................................................................... 12
Cereal Grain Consumption in Obesity and Diabetes................................................................................ 13
Summary....................................................................................................................................................14
References..................................................................................................................................................14

Introduction
Cereal grains are consumed as the primary source of energy by most humans. Consumption of whole/
unrefined cereal products is known to contribute significantly to health and chronic disease prevention.
Whole cereal grains contain nutritionally significant quantities of dietary fiber, as well as various minerals and vitamins that are important for health. More recent evidence also indicates that cereals contain

significant quantities of phytochemicals, like antioxidants and phytoestrogens, which may significantly
contribute to reported health benefits of whole grain consumption. In most cases, these beneficial compounds are concentrated in outer layers (bran) of the grain (Table 2.1). Unfortunately, modern grain milling methods remove most of these compounds with the bran to produce refined endosperm fractions that
are more appealing to consumers in most food applications.
The refined grain products generally lack the health benefits that whole grains provide. At the moment,
the vast majority of cereal products consumed around the world are made from refined grain. For example, in the United States, the Harris Interactive survey commissioned by the Grain Foods Foundation estimated that whole grain products constituted about 11% of total grain consumption in 2008. Additionally,
only 10% of the U.S. population consumes the daily recommended whole grain intake of at least three
servings per day. On the positive side, emerging strong links between unrefined grain-based diets and
population health, coupled with public education, are renewing consumer interest in whole grain products. For example, various market trend data indicate that whole grain popularity is on the rise with consumers; between 2003 and 2008, the whole grain segment was among the fastest growing food product
categories in the United States. The level of whole grain consumption in the United States in 2008 was
20% higher than it was in 2005.
Efforts to promote whole grain consumption were until relatively recently not based on any strong epidemiological evidence of disease prevention (Slavin 1994), but mostly on recognized need for increased
9


10

Fruit and Cereal Bioactives: Sources, Chemistry, and Applications
Table 2.1
Antioxidant Activity and Dietary Fiber Content of Sorghum and
Wheat Grain and Brana
Antioxidant Activityb

Bran Dietary Fiber (% db)

Sample

Grain

Bran


Grain

Bran

Red wheat
White sorghum
Red sorghum
Black sorghum
Tannin sorghum
CV %

10.6
9.8
53
104
240
3.2

36.3
30.1
230
378
890
4.3

12.6
6.3
10.3
9.8
11.1


47.6
38.3
43.9
45.3
44.5

a

b

Adapted from Awika, J. M., McDonough, C. M., and Rooney, L. W., Journal
of Agricultural and Food Chemistry, 53(16), 6230–34, 2005; Awika, J. M.,
Rooney, L. W., Wu, X. L., Prior, R. L., and Cisneros-Zevallos, L., Journal of
Agricultural and Food Chemistry, 51(23), 6657–62, 2003.
µmol TE/g, measured by the ABTS method.

fiber intake that was known to improve fecal bulk and intestinal transit time, and thus believed to improve
gut health. However, in the recent past, numerous epidemiological and intervention studies from around
the world have demonstrated significant health benefits directly linked to whole grain consumption
(Jacobs et al. 2000). Cereal grain-based products have been linked to reduced incidences of some types
of cancer (Bidoli et al. 1992; Slattery et al. 1997), cardiovascular disease (CVD; Liu et al. 1999; Nettleton
et al. 2009; Tighe et al. 2007), diabetes and obesity (Fung et al. 2001).

Cereal Consumption and Cancer
Evidence linking grain consumption with cancer risk has been reported for some time, even though plausible mechanisms have been mostly speculative. Whole grain consumption is widely believed to help reduce
cancer risk, whereas refined grain products have no beneficial effect. In fact, a few reports have linked
increased consumption of some grains with an elevated risk of certain gastrointestinal cancers (Chen et al.
1993), even though such evidence could be attributed to other factors like aflatoxin (Isaacson 2005) that can
be found in some grains, like corn, when grown in hot environments or handled improperly post harvest.

Sorghum consumption has been particularly linked to reduced incidences of esophageal cancer in
various parts of the world where this type of cancer was endemic, including parts of Africa, Iran, and
China (Vanrensburg 1981). These findings were supported by epidemiological evidence linking sorghum
and millet consumption with 1.4–3.2 times lower mortality from cancer of the esophagus in Sachxi
Province of China (Chen et al. 1993). Interestingly, both authors reported no benefit or elevated risk of
cancer of the esophagus with increased consumption of corn and wheat flour in these studies. The forms
in which these grains were consumed in these regions were not reported. However, dietary patterns in
these areas indicate that wheat, for example, is mostly consumed in a highly refined form in these areas.
A case in point is China, where steamed bread, a major form in which wheat is consumed, is usually
prized for whiteness and smooth texture, properties only possible with highly refined wheat flour. Such
refined products have not been shown to contribute to chemoprevention. On the other hand the beneficial
effects reported for sorghum consumption may be related to the fact that sorghum is mostly consumed
with limited to no refining. Additional evidence also indicates that sorghum contains high levels of phytochemicals relative to other cereals (Awika et al. 2003). The sorghum phytochemicals may also have
higher bioactivity than those found in other grains. For example, recent evidence demonstrates that some
unique compounds in sorghum (e.g., 3-deoxyanthocyanins) may have stronger chemoprotective properties than their analogs from other plant sources (Yang, Browning, and Awika 2009).
In the recent past, a flood of evidence (based on epidemiological and intervention studies) linking
cereal grain consumption with reduced incidences of, especially, gastrointestinal cancer have emerged


Health Promoting Effects of Cereal and Cereal Products

11

(Jacobs et al. 1998a; Kasum et al. 2001; Larsson et al. 2005; Levi et al. 2000; Schatzkin et al. 2008).
In almost all cases, the positive benefits are only realized when grain is consumed in an unrefined
form, or when cereal bran components are included in a diet. Thus it is safe to assume that the refined
cereal endosperm products will not provide any meaningful health benefits beyond basic nutrition. For
example, Larsson et al. (2005) reported a risk of 0.65 for colon cancer among those who consumed
at least 4.5 servings of whole grain per day compared to those who consumed less than 1.5 servings.
Levi et al. (2000) reported a significant reduction in the risk of oral, esophageal, and laryngeal cancer

with increased consumption of whole grain as opposed to refined grain products. Numerous bodies of
evidence that corroborate the link between whole grain consumption and gastrointestinal cancer are
available in literature. Most of these investigations have, however, been conducted in developed countries. It is still not known how these data would translate to developing countries where malnutrition
and presence of other confounding factors, like aflatoxin in grain, can be significant. This should be
investigated since the developing countries consume a lot more cereal grain as a proportion of diet than
the developed countries.
Less clear is the link between whole grain consumption and some hormonally dependent cancers, such
as breast cancer (La Vecchia and Chatenoud 1998). For example, a recent cohort study by Egeberg et
al. (2009) failed to find a link between whole grain consumption and breast cancer risk among Danish
postmenopausal women, similar to previous findings (Fung et al. 2005; Nicodemus, Jacobs, and Folsom
2001). On the other hand Kasum et al. (2001) reported that even though there was no statistical association between whole grain intake and endometrial cancer among postmenopausal women in general, a
significant reduction in risk was observed when women who never used hormone replacement ­therapy
were considered independently. In general, however, the link between breast and other hormonally
dependent cancers and cereal grain consumption is weak. This may be due partly to the generally low
levels and wide variation in phytoestrogens (usually lignans) in cereal grains. Additional evidence is
needed in this regard.

Possible Mechanisms of Cereal Grains in Chemoprevention
Various mechanisms have been proposed for the effects of whole grain on cancer risk based on animal
and in vitro model studies. Since the strongest evidence of whole grain consumption and cancer risk are
for gastrointestinal cancer, it is believed cereal components may exert their effects via direct interaction
with gastrointestinal epithelial cells. The mechanisms can be summarized into four broad and generally
inclusive categories: dietary fiber related mechanisms, antioxidant related mechanisms, phytoestrogen
related mechanisms, and mediation of glucose response (Slavin 2000).

Dietary Fiber Related Mechanisms
Dietary fiber is believed to impart its beneficial effect by two mechanisms: (1) increasing fecal bulk and
reducing intestinal transit time, thus limiting interaction of potential fecal mutagens with intestinal epithelium, and (2) fermentation of soluble fiber by colon microflora to produce short chain fatty acids like
butyrate, propionate, and acetate, which lower intestinal pH and promote gut health by diminishing bile
acid solubility and cocarcionogenicity, and also possibly via direct suppression of tumor formation by

butyrate (McIntyre, Gibson, and Young 1993). Thus, different cereal products may impact chemoprotection via different mechanisms depending on their dietary fiber composition.

Antioxidant Related Mechanisms
Oxidative damage can lead to chronic cell injury, which is one of the mechanisms that may lead to cancer (Klaunig et al. 1998). Whole grains are rich in antioxidant phenolics (e.g., ferulates and flavonoids),
­vitamins (e.g., vitamin E), minerals (e.g., selenium), and other components mostly concentrated in their
bran and germ. These dietary antioxidants directly suppress oxidative damage by quenching potentially
damaging free radicals generated by various metabolic processes. They are also known to suppress the


12

Fruit and Cereal Bioactives: Sources, Chemistry, and Applications

growth of preformed cancer cells, which may contribute to elimination of cancer in early stages. Some
of the antioxidants (e.g., selenium) are also cofactors of antioxidant enzymes, while others may enhance
activity of protective phase II enzymes (Yang, Browning, and Awika 2009). For example, sorghum is an
especially rich source of antioxidants (Table 2.1); this may partly explain the distinct chemoprotective
properties against esophageal cancer reported for sorghum relative to corn or wheat.

Phytoestrogen Related Mechanisms
Estrogenic effects of cereals may be produced by lignans that are found in low quantities in cereal brans.
These plant lignans (e.g., secoisolariciresinol) can be metabolized by intestinal microflora into mammalian lignans like enterodiol, which are estrogenic. Other authors have suggested that dietary fiber may
also interrupt enterohepatic circulation of estrogen, leading to increased fecal estrogen secretion (Goldin
et al. 1982).

Mediation of Glucose Response
Since a link between the cause of obesity and cancer has been suggested, it is believed that whole grains,
through their effect of slowing glycemic response and thus insulin secretion, may contribute to chemoprevention (Schoen et al. 1999). See the section near the end of this chapter about cereal grain consumption in obesity and diabetes for more detail.

Cereal Grain Consumption and Cardiovascular Disease

Cardiovascular disease (CVD) remains the leading cause of deaths in much of the developed world,
and a major contributor to morbidity and health care costs. It has been long recognized that diets rich
in unrefined grain or grain components, as well as dietary fiber can help significantly lower the risk for
CVD (Trowell 1972), even though systemic evidence began emerging only in the latter part of the 1990s.
A recent meta-analysis of several cohort studies estimated that an average of 2.5 servings of whole grain
per day reduced the risk of CVD events by 21% compared to 0.2 servings/day of whole grain (Mellen,
Walsh, and Herrington 2008). Evidence indicates that the beneficial effect of cereal grains on cardiovascular health may be related to bran components. For example, Jensen et al. (2004) reported that adding
bran to a whole grain diet reduced coronary heart disease (CHD) risk by 30% compared to whole grain
alone, which reduced the risk by 18% among male professionals aged 40–75 years. The authors found
that the added germ had no effect on CHD risk. Similar findings have been documented in various other
studies. This type of evidence initially led to the assumption that the dietary fiber in the bran part of
whole grain was primarily responsible for the beneficial effect. However, other studies have found that
the benefit of whole grain consumption cannot be fully explained by their dietary fiber content alone
(Liu et al. 1999).
Other than soluble and insoluble dietary fiber, cereal bran contains a complex mixture of antioxidant
molecules, phytoseterols, policosanols, phytoestrogens, trace minerals, vitamins, and other compounds
that have been associated with positive cardiovascular outcomes in controlled studies. Effects of cereal
dietary fiber components on cardiovascular health are well documented. However, the exact mechanisms
involved are not very clear. Some studies have reported a higher effect of insoluble cereal fiber on cardiovascular health than soluble fibers (Lairon et al. 2005), while others have reported the opposite effect.
However, such inconsistencies may be due to the simple fact that it is often difficult, if not impossible, to
isolate the effect of various forms of dietary fiber in cereals on cardiovascular health. In general, there is
an agreement that soluble dietary fiber increases viscosity of gastric content, reducing the rate of absorption of nutrients. This may improve glycemic response and consequently reduce insulin demand and
improve the blood lipid profile. The soluble fibers may also exert their effect via partial fermentation into
short chain fatty acids by colon microflora; reducing colon pH and thus reducing bile acid solubility and
sterol reabsorption. Some short chain fatty acids, especially butyric and propionic acid, may also directly
inhibit cholesterol biosynthesis.


Health Promoting Effects of Cereal and Cereal Products


13

Cereal bran wax components, specifically phytosterols and policosanols have been reported in various studies to reduce cholesterol absorption and biosynthesis. For example, sorghum dry distiller grain
hexane extracts were shown to significantly reduce cholesterol absorption by up to 17% and non-HDL
plasma cholesterol by up to 70% in animal models (Carr et al. 2005). The authors attributed the unusually potent effect of sorghum lipid extracts to the relatively high policosanol content of sorghum bran.
Phenolics and other antioxidants found in cereal bran are also believed to contribute to cardiovascular
health by reducing inflammation and LDL oxidation, as well as improving endothelial function, and
inhibiting platelet aggregation. Some studies have also implicated phenolic compounds in cholesterol
reduction (Fki, Sahnoun, and Sayadi 2007; Parker et al. 1996). Phytoestrogens found in cereal bran
(mostly lignans) are hypothesized to promote favorable vascular responses to stress as well as endothelium-modulated dilation by inhibiting platelet aggregation or platelet release of vasoconstrictors (Anderson
et al. 2000; Slavin, Jacobs, and Marquart 1997).
It seems that the net effect of whole grain diets on cardiovascular health is a result of synergistic
and complex interactions of dietary fiber with various minor components in ways that are not yet fully
understood. This may also explain why isolated cellulose fiber does not produce similar cardiovascular
benefits as whole grain or cereal bran (Kahlon, Chow, and Wood 1999).

Cereal Grain Consumption in Obesity and Diabetes
Appetite suppression and control is the single most important mechanism to regulate calorie intake and
thus affect weight gain. Satiety (longer duration between meals) and satiation (lower meal energy intake)
play key roles in appetite control and energy intake. Whole grain products are believed to influence
satiety and satiation due, at least partly, to their effect on glycemic response. Unrefined grain products
are digested and absorbed more slowly, resulting in smaller postprandial glucose responses and insulin
demand on the pancreatic β cells (Slavin, Jacobs, and Marquart 1997). By regulating insulin response,
whole grain products may prevent problems associated with elevated blood insulin, including altered adipose tissue physiology and increased lipogenesis and appetite. Ludwig et al. (1999) reported that the high
glycemic index (GI) foods may actually promote overeating in obese children. The authors reported that
voluntary energy intake after a high GI meal was 53% higher than after a medium GI meal among obese
teenage boys. On the other hand, Burton-Freeman and Keim (2008) reported that high GI meals resulted
in greater satiety and suppression of hunger than low GI meals in obese women. The authors concluded
that low GI diets may not be suitable for optimal appetite and satiety among overweight women.
Such controversy is understandable given that satiety and GI are not by themselves precise measures of

anything meaningful. Satiety is highly subjective and related to behavioral factors not fully understood.
Additionally, GI in itself is highly variable depending on measuring conditions, among other factors, and
its use as a predictor on the health impact of carbohydrate consumption remains very much questionable.
Such variability have led some authors to propose doing away with the GI as such and evaluating meal
quality based on individual and demonstrated merits like whole grain content (Sloth and Astrup 2006).
All the same, glycemic response as a mechanism is useful in explaining some observations related
to whole grain and dietary fiber intake. The reduced glycemic response of whole grain foods is partly
attributed to the dietary fiber. Both soluble and insoluble dietary fiber found in whole grain products
can provide a physical barrier to digestive enzymes, thus resulting in slow and sometimes incomplete
digestion of starch. Indeed, it is known that whole grain products have higher type 1 resistant starch
(physically inaccessible starch) than refined grain counterparts. The soluble part of dietary fiber may
additionally increase gastric lumen viscosity that further slows digestion and macronutrient absorption.
Another factor that may contribute to reduced insulin response is the reduced energy intake due to the
bulking effect of dietary fiber that reduces energy density of a meal and increases satiation.
However, dietary fiber alone does not explain the insulin response modulating properties of whole
grain products. For example, long-term wheat bran consumption was shown to improve glucose tolerance better than pectin (Brodribb and Humphreys 1976). Other components concentrated in the bran and
possibly germ, like antioxidants, vitamin E, and Mg, may also contribute to insulin sensitivity. Oxidative
stress has been associated with reduced insulin-dependent glucose disposal and diabetic complications