Bioactives in Fruit E-Book

• Herausgeber: John Wiley & Sons
• Kategorie: Fachliteratur
• Sprache: Englisch

Seitenzahl: 1302

Veröffentlichungsjahr: 2013

Beschreibung

For centuries we have known that fruit is important for health, but we are only just beginning to fully understand why.  Bioactives in Fruit: Health Benefits and Functional Foods aims to summarise some of our current knowledge on the bioactive compounds that are associated with the health benefits of specific fruits with a strong emphasis on the validation of health benefits by human intervention trials. Reflecting the current interest in food and health, the book includes strategies to retain and enhance the bioactives in fruit through breeding, growing conditions, fruit storage, processing into ingredients and production of functional foods.

To accomplish this task authors with expertise in biology, chemistry, pharmacology, food science, nutrition, medicine, and horticulture have contributed. They come from universities, government and industry funded research institutes and biotechnology and food companies in Europe, the United States, Asia and New Zealand to give the book a broad perspective.

This book, describing fruit bioactives, their health benefits when consumed as a food and related topics regarding their development into fresh or processed functional foods, will be of use to postgraduate
students, researchers, functional food product developers, food regulators and anyone who has curiosity about why fruit is good for you.  The information contained within will provide plant breeders with new targets for the development of value-added horticultural products, and will also provide nutritionists and dieticians with a useful resource for developing strategies to assist in preventing or slowing disease onset or severity. Bioactives in Fruit: Health Benefits and Functional Foods is a major resource which will be required reading for anyone working in the fields of health and functional foods.

Leseprobe

Contents

Cover

Title Page

Copyright

Contributors

Preface

Chapter 1: Introduction to the Major Classes of Bioactives Present in Fruit

BIOACTIVES

CLASSIFICATION OF PLANT-DERIVED BIOCTIVES

BIOACTIVES IN FRUITS

CONCLUSION

REFERENCES

Chapter 2: Fibre in Fruit

INTRODUCTION

DIETARY FIBRE

FRUIT

PLANT TISSUES AND TYPES OF CELL WALLS

CELL WALL POLYSACCHARIDES

EFFECTS OF COOKING OR PROCESSING ON CELL WALL COMPOSITION

HEALTH BENEFITS

FUTURE CONSIDERATIONS FOR HEALTH FUNCTIONALITY

REFERENCES

Chapter 3: Bioavailability of Antioxidant Compounds from Fruits

INTRODUCTION

ANTIOXIDANTS IN FRUITS

FACTORS THAT AFFECT ANTIOXIDANT RESPONSE TO INGESTION OF FRUIT: ‘APPARENT’ AND ‘REAL’ BIOAVAILABILITY

GETTING TO THE END: A NOTE ON COLONIC METABOLITES

FINALLY, INCREASING BIOAVAILABILITY OF ANTIOXIDANTS: CAN IT AND SHOULD IT BE DONE?

CONCLUSIONS

ACKNOWLEDGEMENTS

DECLARATION OF INTEREST

REFERENCES

Chapter 4: Pharmacokinetic and Pharmacodynamic Interaction of Functional Foods with Medicines

INTRODUCTION

FRUITS

GINKGO BILOBA EXTRACT (GBE)

GREEN TEA

SAW PALMETTO EXTRACT (SPE)

CONCLUSIONS

ACKNOWLEDGEMENTS

REFERENCES

Chapter 5: Health Properties of Apple and Pear

INTRODUCTION

THE ORIGIN OF APPLES

DOMESTICATION OF APPLES

APPLE PRODUCTION

MAJOR CLASSES OF APPLE BIOACTIVES

BIOSYNTHESIS AND GENETIC REGULATION OF APPLE BIOACTIVES

APPLE AND HUMAN HEALTH

STORAGE AND PROCESSING

STRATEGIES TO IMPROVE THE BIOACTIVE CONTENT OF APPLES

CONCLUSIONS

REFERENCES

Chapter 6: Orange and Grapefruit Bioactive Compounds, Health Benefits and Other Attributes

INTRODUCTION

COMPOSITION OF CITRUS

BIOAVAILABILITY AND METABOLIZATION OF CITRUS PHYTOCHEMICALS

CITRUS AND SPECIFIC AILMENTS

ATTRIBUTES OF CITRUS HAVING RAISED DISPROPORTIONATE CONCERNS

CONCLUSIONS

REFERENCES

Chapter 7: Health Benefits from Pomegranates and Stone Fruit, Including Plums, Peaches, Apricots and Cherries

INTRODUCTION

THE ORIGIN, DIVERSITY AND TRADITIONAL USES OF THE POMEGRANATE (PUNICA GRANATUM L.)

THE ORIGIN, DIVERSITY AND TRADITIONAL USES OF THE STONE FRUITS (PRUNUS L.)

PHYTOCHEMICAL COMPOSITION

EFFECT OF PROCESSING AND STORAGE ON POMEGRANATE AND STONE FRUIT BIOACTIVES

HEALTH EFFECTS OF POMEGRANATES

HEALTH EFFECTS OF STONE FRUIT

CONCLUSION

REFERENCES

Chapter 8: The Potential Health Benefits of the Subtropical Fruits Kiwifruit, Feijoa and Tamarillo

INTRODUCTION

KIWIFRUIT

FEIJOA

TAMARILLO

CONCLUSION

REFERENCES

Chapter 9: Effect of Health-promoting Properties of Grapes, Including Resveratrol

INTRODUCTION

BIOAVAILABILITY AND METABOLIC FATE OF COMPOUNDS

HEART HEALTH BENEFITS AND POTENTIAL MECHANISMS OF ACTION

IMMUNITY

CANCER

OBESITY, METABOLIC SYNDROME AND DIABETES

COGNITION

CONCLUSION

ACKNOWLEDGEMENTS

REFERENCES

Chapter 10: Potential Health Benefits of Blackcurrants

INTRODUCTION

BIOACTIVITY OF ANTHOCYANINS AND METABOLITES

FUTURE DIRECTION OF RESEARCH

LIST OF ABBREVIATIONS

REFERENCES

Chapter 11: Overview of the Health Properties of Blueberries

INTRODUCTION

BIOACTIVE COMPONENTS OF BLUEBERRIES

OBESITY AND INSULIN RESISTANCE

TYPE 2 DIABETES MELLITUS

CARDIOVASCULAR DISEASES

CANCER

LONGEVITY

NEUROPROTECTION AND AGING

GASTROINTESTINAL DISEASES

VISION

CONCLUSION

REFERENCES

Chapter 12: Cranberry Polyphenols in the Promotion of Urinary Tract, Cardiovascular and Emerging Health Areas

INTRODUCTION

BIOACTIVES IN CRANBERRY

HEALTH BENEFITS OF CRANBERRY

CONCLUSION

REFERENCES

FURTHER READING/RESOURCES

Chapter 13: Vegetable Fruits: A Cornucopia of Health Benefits

INTRODUCTION

TOMATOES

CAPSICUM

OTHER SOLANACEOUS VEGETABLE FRUITS

CUCURBITACEAE

OTHER VEGETABLE FRUITS

CONCLUSIONS

REFERENCES

FURTHER READING/RESOURCES

Chapter 14: Potential Health Benefits of Avocados

INTRODUCTION

ANTIOXIDANT PROPERTIES

CARDIOVASCULAR AND METABOLIC DISEASE

OSTEOARTHRITIS/BONE HEALTH

INFLAMMATION

CANCER

NEUROPROTECTION

WOUND HEALING

AGING

TOXICITY

CONCLUSIONS

REFERENCES

Chapter 15: Cardiovascular Benefits of Olive Oil: Beyond Effects of Fat Content

INTRODUCTION

FACTORS AFFECTING PHENOL COMPOUND CONTENT IN VOO

THE HEALTH EFFECT OF VOO

CONCLUSION AND FUTURE PERSPECTIVES

ACKNOWLEDGEMENTS

REFERENCES

Chapter 16: Cocoa, Blood Flow and the Brain

INTRODUCTION

CULTIVATION AND EXTRACTION

ACTIVE COMPONENTS

PHARMACOKINETICS AND ABSORPTION

MECHANISM OF ACTION

HUMAN INTERVENTION TRIALS

EPIDEMIOLOGICAL EVIDENCE

CONCLUSIONS

REFERENCES

Chapter 17: Breeding for Enhanced Bioactives in Berry Fruit

INTRODUCTION

BREEDING BERRY FRUIT FOR IMPROVED BIOACTIVES

USE OF GENETIC ENGINEERING FOR IMPROVING BIOACTIVE COMPOUNDS

CONCLUSIONS

REFERENCES

Chapter 18: The Influence of Pre- and Postharvest Environmental Stress on Fruit Bioactives

INTRODUCTION

THE MAIN GROUPS OF FRUIT BIOACTIVES SENSITIVE TO ENVIRONMENTAL STRESSORS AND THEIR ASSOCIATIONS WITH HUMAN HEALTH

THE MAIN ENVIRONMENTAL STRESSORS THAT CAN INFLUENCE THE LEVELS OF BIOACTIVES IN FRUITS

THE INFLUENCE OF ENVIRONMENTAL STRESSORS AND OTHER TREATMENTS ON THE LEVELS OF BIOACTIVES IN SOME COMMERCIALLY IMPORTANT FRUITS

XENOHORMESIS: AN ANCIENT RESPONSE WITH MODERN APPLICATIONS

REFERENCES

Chapter 19: Recovery of Valuable Bioactives from Residues Arising from Fruit Processing

INTRODUCTION

MEMBRANE SEPARATION AND FILTRATION

ADSORPTION AND ION EXCHANGE PROCESSES

SUMMARY

NOMENCLATURE

REFERENCES

Chapter 20: Stability and Bioaccessibility of Fruit Bioactives in Foods: Food Component Interactions and Matrix Effect

INTRODUCTION

KEY COMPONENTS PRESENT IN FRUIT-BASED FUNCTIONAL FOODS

INTERACTIONS BETWEEN FRUIT BIOACTIVES AND OTHER FOOD COMPONENTS IN VARIOUS FOOD SYSTEMS

CONCLUSION AND FUTURE OUTLOOK

REFERENCES

Index

This edition first published 2013 © 2013 by John Wiley & Sons, Ltd

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Library of Congress Cataloging-in-Publication Data

Bioactives in fruit : health benefits and functional foods / editors, Margot Skinner, Denise Hunter.   p. ; cm.  Includes bibliographical references and index.  ISBN 978-0-470-67497-0 (cloth : alk. paper) – ISBN 978-1-118-63555-1 – ISBN 978-1-118-63556-8 (ePDF) – ISBN 978-1-118-63558-2 (emobi) – ISBN 978-1-118-63559-9 (epub)  I. Skinner, Margot. II. Hunter, Denise.  [DNLM: 1. Fruit–chemistry. 2. Biological Availability. 3 Functional Food. 4. Phytotherapy–methods. 5. Plant Extracts. WB 430]  RA784  613.2–dc23

2013006647

A catalogue record for this book is available from the British Library.

Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic books.

Cover image © Steven Allan/istockphoto.com Cover design by Meaden Creative

Contributors

Francisco A. Tomás-BarberánCEBAS-CSIC Department of Food Science and Technology Murcia Spain

Iris F.F. BenzieDepartment of Health Technology and Informatics The Hong Kong Polytechnic University Kowloon Hong Kong

David J. BurrittDepartment of Botany University of Otago Dunedin New Zealand

Antonio Camargo GarciaLipids and Atherosclerosis Unit IMIBIC/Reina Sofia University Hospital/University of Cordoba, and CIBER Fisiopatologia Obesidad y Nutricion (CIBEROBN) Instituto de Salud Carlos III Spain

Paul F. CancalonFlorida Department of Citrus Lake Alfred Florida USA

Reinhold CarleHohenheim University Institute of Food Science and Biotechnology Stuttgart Germany

William T. CefaluDiabetes and Nutrition Laboratory Pennington Biomedical Research Center Baton Rouge Louisiana USA

Suengmok ChoKorea Food Research Institute Seongnam Republic of Korea

Alastair CurrieThe New Zealand Institute for Plant and Food Research Ltd Motueka New Zealand

Gary M. DavenportP&G Pet Care Mason Ohio USA

Yoshiharu DeguchiLaboratory of Drug Disposition and Pharmacokinetics School of Pharmaceutical Sciences Teikyo University Japan

Michael EdwardsDepartment of Nutrition Norwich Medical School University of East Anglia Norwich UK

Carrie M. ElksNutritional Neuroscience and Aging Laboratory Pennington Biomedical Research Center Baton Rouge Louisiana USA

Richard EspleyThe New Zealand Institute for Plant & Food Research Auckland New Zealand

Joseph FrancisComparative Biomedical Sciences Louisiana State University School of Veterinary Medicine Baton Rouge Louisiana USA

María I. GilCEBAS-CSIC Department of Food Science and Technology Murcia Spain

Anusooya GnanavinthanFood Science, School of Chemical Sciences The University of Auckland Auckland New Zealand

Crystal F. HaskellBrain, Performance and Nutrition Research Centre School of Life Sciences Northumbria University Newcastle upon Tyne UK

Denise HunterThe New Zealand Institute for Plant & Food Research Ltd Auckland New Zealand

Donald K. IngramNutritional Neuroscience and Aging Laboratory Pennington Biomedical Research Center Baton Rouge Louisiana USA

Kerrie L. KasparOcean Spray Cranberries, Inc. Lakeville-Middleboro Massachusetts USA

Dietmar Rolf KammererHohenheim University Institute of Food Science and Biotechnology Stuttgart Germany

Colin KayDepartment of Nutrition Norwich Medical School University of East Anglia Norwich UK

Christina KhooOcean Spray Cranberries, Inc. Lakeville-Middleboro Massachusetts USA

Carolyn E. ListerThe New Zealand Institute for Plant & Food Research Limited Lincoln New Zealand

Jose Lopez-MirandaLipids and Atherosclerosis Unit IMIBIC/Reina Sofia University Hospital/University of Cordoba, and CIBER Fisiopatologia Obesidad y Nutricion (CIBEROBN) Instituto de Salud Carlos III Spain

Stefan MartensFondazione Edmund Mach, Istituto Agrario di San Michele all'Adige (IASMA) Centro Ricerca e Innovazione, Dipartimento Qualita' Alimentare e Nutrizone, Biotecnologia dei Prodotti Naturali San Michele all'Adige Italy

Bruno MezzettiUniversità Politecnica delle Marche Ancona Italy

Rosalind MillerGlaxoSmithKline Brentford UK

Shingen MisakaDepartment of Pharmacology, School of Medicine Fukushima Medical University Fukushima Japan

Conchita ObónDepartamento de Ciencia y Tecnología de Alimentos Universidad Miguel Hernández Orihuela Spain

Takashi OkuraLaboratory of Drug Disposition and Pharmacokinetics School of Pharmaceutical Sciences Teikyo University Japan

Susan S. PercivalFood Science and Human Nutrition Department University of Florida Gainesville Florida USA

Francisco Perez-JimenezLipid and Atherosclerosis Unit IMIBIC/Reina Sofía University Hospital/University of Cordoba CIBER Fisiopatología de la Obesidad y Nutrición (CIBEROBN) Instituto de Salud Carlos III Cordoba, Spain

Sophie PutnamGlaxoSmithKline Brentford UK

Diego RiveraDepartamento de Botánica Universidad de Murcia Murcia Spain

George S. RothGeroScience, Inc. Pylesville Maryland USA

David RuizCEBAS-CSIC Department of Food Science and Technology Murcia Spain

Zaid SalehThe University of Auckland, Department of Chemical and Materials Engineering The New Zealand Institute for Plant and Food Research Limited Auckland New Zealand

Catalina Sánchez-RocaDepartamento de Botánica Universidad de Murcia Murcia Spain

Jessica ScalzoThe New Zealand Institute for Plant and Food Research Ltd Hawkes Bay New Zealand

Barbara Shukitt-HaleNeuroscience Laboratory USDA Human Nutrition Research Center on Aging Tufts University Boston Massachusetts USA

Margot SkinnerFood Science, School of Chemical Sciences The University of Auckland Auckland New Zealand

Stephen J.M. SkinnerDepartment of Physiology Faculty of Medicine and Health Sciences The University of Auckland Auckland New Zealand

Bronwen G. SmithFood Science, School of Chemical Sciences The University of Auckland Auckland New Zealand

April J. StullDiabetes and Nutrition Laboratory Pennington Biomedical Research Center Baton Rouge Louisiana USA

Dongxiao Sun-WaterhouseThe New Zealand Institute for Plant & Food Research Limited Auckland New Zealand

Yuko TakiDepartment of Pharmacokinetics and Pharmacodynamics School of Pharmaceutical Sciences University of Shizuoka Japan

Keizo UmegakiInformation Center, National Institute of Health and Nutrition Shinjuku-ku, Tokyo Japan

Daniel ValeroDepartamento de Ciencia y Tecnología de Alimentos Universidad Miguel Hernández Orihuela Spain

Sissi Wachtel-GalorDepartment of Health Technology and Informatics The Hong Kong Polytechnic University Kowloon Hong Kong

Hiroshi WatanabeDepartment of Clinical Pharmacology and Therapeutics Hamamatsu University School of Medicine Japan

Yasuo WatanabeYokohama College of Pharmacy General Health Medical Center Yokohama Japan

Anthony W. WatsonBrain, Performance and Nutrition Research Centre School of Life Sciences Northumbria University Newcastle upon Tyne UK

Robin L. WestDepartment of Psychology University of Florida Gainesville Florida USA

Gary WoodwardDepartment of Clinical Biochemistry Oxford University Hospitals Oxford UK

Shizuo YamadaDepartment of Pharmacokinetics and Pharmacodynamics School of Pharmaceutical Sciences University of Shizuoka Japan

Elena M. Yubero-SerranoBrookdale Department of Geriatrics and Palliative Medicine Division of Experimental Diabetes and Aging Division Mount Sinai School of Medicine New York, NY USA

Preface

For centuries we have known that fruit is important for health but we are only just beginning to fully understand why. This book aims to summarize some of our current knowledge on the bioactive compounds that are associated with the health benefits of specific fruits with a strong emphasis on the validation of health benefits by human intervention trials. Because of the present interest in food and health, the book includes strategies to retain and enhance the bioactives in fruit through growing conditions, fruit storage, processing into ingredients and production of functional foods. To accomplish this task authors with expertise in biology, chemistry, pharmacology, food science, nutrition, medicine and horticulture have contributed. They come from universities, government and industry-funded research institutes and from biotechnology and food companies in Europe, the United States, Asia and New Zealand to give the book a broad perspective.

A brief introduction on the major classes of bioactives present in fruit is followed by a chapter on fruit fibre, exploring the many different chemical compositions that fibre from different sources, including commercial preparations, may contain. This is an important aspect to consider when attempting to attribute health benefits to fibre and when developing new fibre containing foods. The focus of the next chapter is the bioavailability of antioxidant compounds from fruit and includes vitamins C and E, as well as carotenoids and polyphenolic phytochemicals. It incorporates a discussion of the reasons why plasma antioxidant levels are maintained at low concentrations even when consumed at quite high levels, an important consideration as recommendations for fruit and vegetable consumption increase and supplements containing high amounts of these compounds are promoted by their manufacturers. Bioavailability and bioactivity of both foods and pharmaceuticals are related to their absorption, metabolism, distribution, excretion and transport across cell membranes, together with their ability to bind to specific receptors. The potential for functional food bioactives to interact with pharmaceuticals is considerable due to the large number of constituents that they contain. Some examples of the way in which selected functional foods and nutraceuticals influence the pharmacokinetics and pharmacodynamics of drugs are the subject of the next chapter, emphasizing the need to understand whether interactions of foods with medicines are clinically harmful or beneficial to drug therapy.

There then follow a number of chapters on the bioactives and health benefits of common and not-so-common fruits, which include apple and pear, citrus, pomegranate and stone fruit, grapes, blackcurrants, blueberry, cranberry and kiwifruit, feijoa and tamarillo. ‘Vegetable’ fruits, olives, avocado and cocoa, plant foods not commonly consumed as ‘fruit’, are not left out. The chapters are written from different perspectives depending on the interests and research focus of the authors. For example, the chapter on apples and pears includes an update on the biosynthesis and genetic regulation of bioactives within apples. The chapter on citrus includes attributes of citrus that have raised health concerns and again discusses the grapefruit–drug interactions alluded to in an earlier chapter, including ways that this may be overcome now and in the future. The chapter on blueberries includes a detailed examination of mechanistic and pre-clinical studies in models that range from longevity in fruit flies to myocardial ischemia in rats.

The health areas covered in the book span a wide range. These include basic antioxidant activity and all it may be associated with, immune modulation including positive effects associated with asthma, antibacterial properties and reduction of symptoms of infections such as cold and influenza, cardiovascular health, bone health, obesity, metabolic syndrome and diabetes, eye health and vision, oral and gastrointestinal health, urinary tract health, cognition and anxiety and, associated with a number of these areas, longevity. Supporting data, including results from mechanistic, in vitro and in vivo animal studies, are discussed together with validation from human intervention trials, and tentative or firm conclusions drawn, depending on the evidence available. It should be mentioned that epigenetic and nutrigenomic factors that may influence how individuals respond to the bioactive components in fruit is beyond the scope of this book. Once intervention trials are designed and conducted to provide more personalized outcomes, we may find that some of the equivocal results that are often obtained in intervention trials will be clarified and health benefits of functional foods be more commonly assigned to particular groups or genotypes.

The next two chapters are on the subject of horticulture. Using anthocyanins as an example, a chapter on breeding for enhanced levels of these bioactive compounds in blackcurrant and blueberry outlines gains that may be achieved through conventional breeding techniques, as well as the potential for using genetic transformation in strawberries as a proof of concept. As many of the bioactives in fruit are secondary metabolites, whose levels increase in plant cells after exposure to environmental stress, the potential of stress priming to enhance the bioactive contents of fresh fruit or produce new fruit-based products is considered in the chapter following.

The book finishes with two chapters that highlight different aspects of functional foods. In a chapter on recovery of bioactive compounds from entities such as peel and seeds, where they are present in high amounts, innovative process technologies are described that can be applied to purify, enrich and selectively fractionate the compounds from crude extracts recovered from food processing byproducts. The recovery of such components for use as bioactive compounds in functional or enriched foods, as well as dietary supplements, is presented as a promising strategy to produce ingredients and products from waste streams to help achieve sustainable agricultural food production. The last chapter discusses many of the interactions that may occur between fruit bioactives and other food components when they are incorporated into finished processed foods. It goes on to point out that it is the complexity of finished foods, coupled with the processing conditions, that influence the stability, bioaccessability and, ultimately, the bioavailability of the fruit bioactive compounds in a finished processed functional food product.

The information gathered in this book, describing fruit bioactives, their health benefits when consumed as a food and related topics regarding their development into fresh or processed functional foods, will be of use to postgraduate students, researchers, functional food product developers, food regulators and anyone who has curiosity about why ‘fruit is good for you’. The information contained within may provide plant breeders with new targets for the development of value-added horticultural products. It may also provide nutritionists and dieticians with a useful resource for developing strategies to assist in preventing or slowing disease onset or severity. In many instances, the regular consumption of specific fruits in a quantity that is pleasurable and achievable within the context of the diet is all that may be required.

We extend our sincere thanks to the many individuals who have contributed so generously in accomplishing this project.

Margot Skinner

Denise Hunter

1 Introduction to the Major Classes of Bioactives Present in Fruit

Anusooya Gnanavinthan

BIOACTIVES

Bioactives are compounds that produce physiological effects when present in a living material, in other words they must exert physiological benefits related to promoting health and preventing effects of a disease (e.g. blood pressure reduction, blood glucose reduction etc.) (Aluko, 2011; Awika, 2011). When bioactives are taken orally, the compound must withstand the digestion that will destroy the active structure and render it physiologically inactive. But, in some cases, the inactive part of the compound becomes active once consumed, as a result of the action of digestive enzymes present in the gastrointestinal tract (Aluko, 2011). Also, bioactive compounds may exert their physiological effect within the digestive tract and may not be absorbed. However, in most cases, the compound must be absorbed from the gastrointestinal tract into the blood circulatory system, from where it is carried to target organs. Foods that contains bioactives, and that are consumed as part of a normal diet, are called functional foods (Shahidi, 2009).

Plants are a rich source of bioactive compounds. Plant-derived bioactive products such as fruits, vegetables and nuts are becoming popular because of their abundance and low cost (compared to animal products), and due to the wider acceptability of plant products as a result of religious, social or moral reasons that prevent many people consuming animal-derived products (Omaye et al., 2000; Aluko, 2011). Bioactives from fruits show antimicrobial activity, anticancer activity, anti-inflammatory activity, immuno-stimulatory activity and antioxidant activity and so on (Hollman and Katan, 1999; Emilio, 2007; Weston, 2010).

CLASSIFICATION OF PLANT-DERIVED BIOCTIVES

Bioactives can be classified based on molecular identity or biopolymer type that includes polyphenolic compounds, indigestible carbohydrates (dietary fibres), functional lipids (mainly in cereals and seeds), proteins and peptides and carotenoids (Figure 1.1).

Fig. 1.1 Possible classification and examples of plant bioactive compounds (Von Elbe and Schwartz, 1996; Hollman and Katan, 1999; Tokuşoğlu and Hall, 2001; El Gharras, 2009; Naczk and Shahidi, 2006).

Phenolic compounds

Plant phenolics are a structurally diverse class of phytochemicals (Naczk and Shahidi, 2006). Phenolic compounds are defined by the presence of at least one aromatic ring bearing one (phenol) or more (polyphenols) hydroxyl substituents, including their functional derivative (e.g. esters and glycosides) (Maffei, 2003). Polyphenols occur as plant secondary metabolites, are widely distributed in the plant kingdom and represent an abundant antioxidant component of the human diet (Tokuşoğlu, 2011). There has been an increased interest in the health benefits of polyphenols due to the corresponding antioxidant capacities (Wang et al., 1996; Sun et al., 2002).

Free radicals (reactive oxygen species) and antioxidant studies play a major role in medicine. Free radicals are produced by many biological reactions in the body and can damage crucial biomolecules. If these free radicals are not scavenged, they may lead to disease conditions (Fan et al., 2007). Reactive oxygen species (ROS), such as superoxide (O2−), the hydroxyl radical (•OH), hydrogen peroxide (H2O2) and lipid peroxide radicals, have been implicated in playing an important role in chronic degenerative disease, such as cancer, inflammatory, cardiovascular and neurodegenerative diseases, and ageing (Mullen et al., 2002; Price et al., 2006; Sies, 2010). The harmful actions of free radicals can be blocked by antioxidants, by scavenging those free radicals and detoxifying the organisms (BeMiller and Huber, 1996; Fan et al., 2007). Therefore, antioxidants are referred to as compounds that can counteract the damaging effects of oxygen in tissues, and the term is applied to molecules that protect from any free radical (molecule with unpaired electron) (Bilgiçli , 2007). Antioxidants in food are defined as any substance that can relay, retard or prevent the development of food rancidity due to oxidation (Gordon, 2001). Natural antioxidants may inhibit lipid peroxidation in food and improve the quality and safety of the food (Fan , 2007). Two inhibitory mechanisms may be involved: direct scavenging of free radicals (primary antioxidant, e.g. vitamin E – α-tocopherol) and indirect scavenging of free radicals (secondary antioxidant) (Gordon, 2001).