FOOD LIPIDS Chemistry, Nutrition, and Biotechnology ppt

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FOOD LIPIDS
Chemistry, Nutrition,
and Biotechnology
THIRD EDITION
Edited by
Casimir C. Akoh
•
David B. Min
Akoh/Food Lipids: Chemistry, Nutrition, and Biotechnology, Third Edition 46632_C000 Final Proof page i 14.2.2008 6:50am Compositor Name: VBalamugundan
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Library of Congress Cataloging-in-Publication Data
Food lipids : chemistry, nutrition, and biotechnology / edited by Casimir C. Akoh and David B. Min.
3rd ed.
p. ; cm.
Includes bibliographical references and index.
ISBN-13: 978-1-4200-4663-2 (hardcover : alk. paper)
ISBN-10: 1-4200-4663-2 (hardcover : alk. paper)
1. Lipids. 2. Lipids in human nutrition. 3. Lipids Biotechnology. 4. Lipids Metabolism. I. Akoh,
Casimir C., 1955- II. Min, David B.
[DNLM: 1. Lipids chemistry. 2. Lipids physiology. 3. Biotechnology methods. 4. Food. 5.
Nutrition Physiology. QU 85 F6865 2008] I. Title.
QP751.F647 2008
612’.01577 dc22 2007031989
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Contents
Preface to the Third Edition vii
Editors ix
Contributors xi
PART I Chemistry and Properties
1. Nomenclature and Classification of Lipids 3
Sean Francis O’Keefe
2. Chemistry and Function of Phospholipids 39

Marilyn C. Erickson
3. Lipid-Based Emulsions and Emulsifiers 63
D. Julian McClements
4. Chemistry of Waxes and Sterols 99
Edward J. Parish, Shengrong Li, and Angela D. Bell
5. Extraction and Analysis of Lipids 125
Fereidoon Shahidi and P.K.J.P.D. Wanasundara
6. Methods for trans Fatty Acid Analysis 157
Magdi M. Mossoba and Richard E. McDonald
7. Chemistry of Frying Oils 189
Kathleen Warner
PART II Processing
8. Recovery, Refining, Converting, and Stabilizing Edible Fats and Oils 205
Lawrence A. Johnson
9. Crystallization and Polymorph ism of Fats 245
Patrick J. Lawler and Paul S. Dimick
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10. Chemical Interesterification of Food Lipids: Theory and Practice 267
Dérick Rousseau and Alejandro G. Marangoni
PART III Oxidation and Antioxidants
11. Chemistry of Lipid Oxidation 299
Hyun Jung Kim and David B. Min
12. Lipid Oxidation of Muscle Foods 321
Marilyn C. Erickson
13. Polyunsaturated Lipid Oxidation in Aqueous System 365
Kazuo Miyashita
14. Methods for Measuring Oxidative Rancidity in Fats and Oils 387
Fereidoon Shahidi and Udaya N. Wanasundara
15. Antioxidants 409

David W. Reische, Dorris A. Lillard, and Ronald R. Eitenm iller
16. Tocopherol Stability and Prooxidant Mechanisms of Oxidized
Tocopherols in Lipids 435
Hyun Jung Kim and David B. Min
17. Effects and Mechanisms of Minor Compounds in Oil on Lipid Oxidation 449
Eunok Choe
18. Antioxidant Mechanisms 475
Eric A. Decker
PART IV Nutrition
19. Fats and Oils in Human Health 499
David Kritchevsky
20. Unsaturated Fatty Acids 513
Steven M. Watkins and J. Bruce German
21. Dietary Fats, Eicosanoids, and the Immune System 539
David M. Klurfeld
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22. Dietary Fats and Coronary Heart Disease 551
Ronald P. Mensink and Jogchum Plat
23. Conjugated Linoleic Acids: Nutrition and Biology 579
Bruce A. Watkins and Yong Li
24. Dietary Fats and Obesi ty 601
Dorothy B. Hausman and Barbara Mullen Grossman
25. Influence of Dietary Fat on the Development of Cancer 633
Howard Perry Glauert
26. Lipid-Based Synthetic Fat Substitutes 653
Casimir C. Akoh
27. Food Applications of Lipids 683
Frank D. Gunstone
PART V Biotechnology and Biochemistry

28. Lipid Biotechnology 707
Nikolaus Weber and Kumar D. Mukherjee
29. Microbial Lipases 767
John D. Weete, Oi-Ming Lai, and Casimir C. Akoh
30. Enzymatic Interesterification 807
Wendy M. Willis and Alejandro G. Marangoni
31. Structured Lipids 841
Casimir C. Akoh and Byung Hee Kim
32. Genetic Engineering of Crops That Produce Vegetable Oil 873
Vic C. Knauf and Anthony J. Del Vecchio
Index 899
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Preface to the Third Edition
The first edition of Food Lipids was published in 1998 and the second edition in 2002 by Marcel
Dekker, Inc. Taylor & Francis Group, LLC, acquired Marcel Dekker and the rights to publish the
third edition. We firmly believe that this book has been of interest and will help those involved in
lipid resear ch and instruction. Many have bought the previous editions and we thank you for your
support. The need to update the information in the second edition cannot be overstated, as more data
and new technologies are constantly becoming available. We have received good comments and
suggestions on how to improve the second edition. The response reassured us that there was indeed
a great need for a textbook suitable for teaching food lipids, nutritional aspects of lipids, and lipid
chemistry courses to food science and nutrition majors. The aim of the first and second editions
remains unchanged: to provide a modern, easy-to-read textbook for students and instructors. The
book is also suitable for upper-level undergraduate, graduate, and postgraduate instruction. Scien-
tists who have left the university and are engaged in research and development in the industry,
government, or academics will find this book a useful reference. In this edition, we have expanded
on lipid oxidation and antioxidants, as these continue to be topics of great interest to the modern
consumer. The title of Part III has also been changed to reflect the recent interest on the importance

of antioxidants and health. Again, we have made every effort to select contributors who are
internationally recognized experts. We thank them for their exceptional attention to details and
timely submissions of their chapters.
Overall, the text has been updated with new and available information. We removed some
chapters and added new ones. Chapter 2 includes a brief discussion of sphingolipids, and Chapter 31
includes one on diacylglycerols. The new additions are Chapters 13, 16, 17, and 25. Although it is
not possible to cover all aspects of lipids, we feel we hav e added and covered most topics that are of
interest to our readers. The book still is divided into five main parts: Chemistry and Properties;
Processing; Oxidation and Antioxidants; Nutrition; and Biotechnology and Biochemistry.
We are grateful to the readers and users of the previous editions and can only hope that we have
improved and updated the latest edition to your satisfaction. We welcome comments on the third
edition to help us continue to provide our readers with factual information on the science of lipids.
Based on the comments of readers and reviewers of the past editions, we have improved the third
edition—we hope, without creating new errors, which are sometimes unavoidable for a book this
size and complexity. We apologize for any errors in advance and urge you to contact us if you find
mistakes or have suggestions to improve the readability and comprehension of this text.
Special thanks to our readers and students, and to the editorial staff of Taylor & Francis Group,
LLC, for their helpful suggestions toward improving the quality of this edition.
Casimir C. Akoh
David B. Min
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Editors
Casimir C. Akoh is a distinguished research professor of food science and technology and an
adjunct professor of foods and nutrition at the University of Georgia, Athens. He is the coeditor of
the book Carbohydrates as Fat Substitutes (Marcel Dekker, Inc.), coeditor of Healthful Lipids
(AOCS Press), editor of Handbook of Functional Lipids (CRC Press), the author or coauth or of over
162 referenced SCI publications, more than 30 book chapters, and the holder of three U.S. patents.
He is a fellow of the Institute of Food Technologists (2005), American Oil Chemists’ Society

(2006), and the American Chemical Society (2006). He serves on the editorial boards of five
journals and is a member of the Institute of Food Technologists, the American Oil Chemists’
Society, and the American Chemical Society. He has received numerous international professional
awards for h is work on lipids including the 1998 IFT Samuel Cate Prescott Award, the 2003 D.W.
Brooks Award, and the 2004 AOCS Stephen S. Chang Award. He received his PhD (1988) in food
science from Washington State University, Pullman. He holds MS and BS degrees in biochemistry
from Washington State University and the University of Nigeria, Nsukka, respectively.
David B. Min’s major research objective is to improve the oxidative and flavor stability of foods by
understanding and controlling the chemical mechanisms for the flavor compound formation by a
combination of GC, HPLC, IR, NMR, ESR, and MS. Dr. Min’s group painstakingly, conclusively,
and scientifically developed the novel chemical mechanisms for the formation of sunlight flavor in
milk, reversion flavor in soybean oil, and light sensitivity of riboflavin. He is a pioneer for the
formation, reaction mechanisms and kinetics, quenching mechanisms and kinetics singlet oxygen in
foods. He has published 6 books and more than 200 publications.
He has been scientific editor of Journal of Food Science and Journal of the American Oil
Chemists’ Society and has been on the editorial board of Journal of Critical Reviews on Food
Science and Nutrition, Journal of Food Quality, Food Chemistry, International News on Fats and
Oils, Food Science and Biochemistry, and Marcel Dekker Publications.
He has received more than 30 national and international awards including the 1995 IFT
Achievement Award of Lipid and Flavor Chemistry, the 1999 Distinguished Senior Faculty
Research Award, the 2001 IFT Food Chemistry Lectureship Award, the 2002 Professor of the
Year Award, and the 2004 Outstanding Teaching Award. He has been an elected member of
the Korean National Academy of Science, and a fellow of the Institute of Food Technologists,
the American Oil Chemists’ Society, the American Institute of Chemists, and the International
Academy of Food Science and Technology.
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Contributors
Casimir C. Akoh

Department of Food Science and Technology
University of Georgia
Athens, Georgia
Angela D. Bell
Department of Chemistry
Auburn University
Auburn, Alabama
Eunok Choe
Department of Food and Nutrition
Inha University
Incheon, Korea
Eric A. Decker
Department of Food Science
University of Massachusetts
Amherst, Massachusetts
Anthony J. Del Vecchio
Monsanto, Inc.
Davis, California
Paul S. Dimick
Department of Food Science
Pennsylvania State University
University Park, Pennsylvania
Ronald R. Eitenmiller
Department of Food Science and Technology
University of Georgia
Athens, Georgia
Marilyn C. Erickson
Center for Food Safety
Department of Food Science and Technology
University of Georgia

Griffin, Georgia
J. Bruce German
Department of Food Science and Technology
University of California
Davis, California
Howard Perry Glauert
Department of Nutrition and Food Science
University of Kentucky
Lexington, Kentucky
Barbara Mullen Grossman
Department of Foods and Nutrition
University of Georgia
Athens, Georgia
Frank D. Gunstone
Scottish Crop Research Institute
Invergowrie, Dundee, Scotland
Dorothy B. Hausman
Department of Foods and Nutrition
University of Georgia
Athens, Georgia
Lawrence A. Johnson
Center for Crops Utilization Research
Department of Food Science and Hum an
Nutrition
Iowa State University
Ames, Iowa
Byung Hee Kim
Department of Food Science and Technology
University of Georgia
Athens, Georgia

Hyun Jung Kim
Department of Food Science and Technology
Ohio State University
Columbus, Ohi o
David M. Klurfeld
United States Department of Agriculture
Agricultural Research Service
Beltsville, Maryland
Vic C. Knauf
Monsanto, Inc.
Davis, California
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David Kritchevsky (Late)
Wistar Institute
Philadelphia, Pennsylvania
Oi-Ming Lai
Department of Bioprocess Technology
Universiti Putra Malaysia
Serdang Selango r, Malaysia
Patrick J. Lawler
McCormick and Company, Inc.
Cockeysville, Maryland
Shengrong Li
Department of Chemistry
Auburn University
Auburn, Alabama
Yong Li
Department of Food Science
Purdue University

West Lafayette, Indiana
Dorris A. Lillard
Department of Food Science and Technology
University of Georgia
Athens, Georgia
Alejandro G. Marangoni
Department of Food Science
University of Guelph
Guelph, Ontario, Canada
D. Julian McClements
Department of Food Science
University of Massachusetts
Amherst, Massachusetts
Richard E. McDonald
Food and Drug Administration
National Center for Food Safety and
Technology
Summit-Argo, Illinois
Ronald P. Mensink
Department of Human Biology
Maastricht University
Maastricht, The Netherlands
David B. Min
Department of Food Science and Technology
Ohio State University
Columbus, Ohio
Kazuo Miyashita
Graduate School of Fisheries Sciences
Hokkaido University
Hakodate, Japan

Magdi M. Mossoba
Food and Drug Administration
Center for Food Safety and Applied Nutrition
College Park, Maryland
Kumar D. Mukherjee
Institute for Lipid Research
Federal Research Centre for Nutrition and Food
Munster, Ger many
Sean Francis O’Keefe
Department of Food Science and Technology
Virginia Polytechnic Institute and State
University
Blacksburg, Virginia
Edward J. Parish
Department of Chemistry
Auburn University
Auburn, Alabama
Jogchum Plat
Department of Human Biology
Maastricht University
Maastricht, The Netherlands
David W. Reische
Dannon Company, Inc.
Fort Worth, Texas
Dérick Rousseau
School of Nutrition
Ryerson Polyt echnic University
Toronto, Ontario, Canada
Fereidoon Shahidi
Department of Biochemistry

Memorial University of Newfoundland
St. John’s, Newfoundland, Canada
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P.K.J.P.D. Wanasundara
Agriculture Agri-Food Canada
Saskatoon Research Centre
Saskatoon, Saskatchewan, Canada
Udaya N. Wanasundara
POS Pilot Plant Corporation
Saskatoon, Canada
Kathleen Warner
National Center for Agricultural Utilization
Research
Agricultural Research Service
U.S. Department of Agriculture
Peoria, Illinois
Bruce A. Watkins
Department of Food Science
Purdue University
West Lafayette, Indiana
Steven M. Watkins
FAME Analytics
West Sacramento, California
Nikolaus Weber
Institute for Lipid Research
Federal Research Centre for Nutrition and Food
Munster, Germany
John D. Weete
West Virginia University

Morgantown, West Virginia
Wendy M. Willis
Yves Veggie Cuisine
Vancouver, British Columbia, Canada
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Part I
Chemistry and Properties
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1
Nomenclature and
Classification of Lipids
Sean Francis O’Keefe
CONTENTS
I. Definitions of Lipids 3
II. Lipid Classifications 4
A. Standard IUPAC Nomenclature of Fatty Acids 5
B. Common (Trivial) Nomenclature of Fatty Acids 7
C. Shorthand (v) Nomenclature of Fatty Acids 8
III. Lipid Classes 9
A. Fatty Acids 9
1. Saturated Fatty Acids 9
2. Unsaturated Fatty Acids 10
3. Acetylenic Fatty Acids 12
4. Trans Fatty Acids 15
5. Branched Fa tty Acids 16
6. Cyclic Fatty Acids 16
7. Hydroxy and Epoxy Fatty Acids 17

8. Furanoid Fatty Acids 18
B. Acylglycerols 20
C. Sterols and Sterol Esters 22
D. Waxes 25
E. Phosphoglycerides (Phospholipids) 26
F. Ether(Phospho)Glyc erides (Plasmalogens) 28
G. Glyceroglycolipids (Glycosylglycolipids) 28
H. Sphingolipids 29
I. Fat-Soluble Vitamins 30
1. Vitamin A 30
2. Vitamin D 31
3. Vitamin E 32
4. Vitamin K 32
J. Hydrocarbons 34
IV. Summary 35
References 35
I. DEFINITIONS OF LIPIDS
No exact definition of lipids exists. Christie [1] defines lipids as ‘‘a wide variety of natural products
including fatty acids and their derivatives, steroids, terpenes, carotenoids, and bile acids, which have
in common a ready solubility in organic solvents such as diethyl ether, hexane, benzene, chloroform,
or methanol.’’
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Kates [2] says that lipids are ‘‘those substances which are (a) insoluble in water; (b) soluble in
organic solvents such as chloroform, ether or benzene; (c) contain long-chain hydrocarbon groups
in their molecules; and (d) are present in or derived from living organisms.’’
Gurr and James [3] point out that the standard definition includes ‘‘a chemically heterogeneous
group of substances, having in common the property of insolubility in water, but solub ility in
nonpolar solvents such as chloroform, hydrocarbons or alcohols.’’
Despite common usage, definitions based on solubility have obvious problems. Some com-

pounds that are considered lipids, such as C1–C4 very short-chain fatty acids (VSCFAs), are
completely miscible with water and insoluble in nonpolar solvents. Some researchers have accepted
this solubility definition strictly and exclude C1–C3 fatty acids in a definition of lipids, keeping C4
(butyric acid) only because of its presence in dairy fats. Additionally, some compounds that are
considered lipids, such as some trans fatty acids (those not derived from bacterial hydrogenation),
are not derived directly from living organisms. The development of synthetic acaloric and reduced
calorie lipids complicates the issue because they may fit into solubility-based definitions but are not
derived from living organisms, may be acaloric, and may contain esters of VSCFAs.
The traditional de finition of total fat of foods used by the U.S. Food and Drug Administration
(FDA) has been the ‘‘sum of the components with lipid characteristics that are extracted by
Association of Official Analytical Chemists (AOAC) methods or by reliable and appropriate
procedures.’’ The FDA has changed from a solubility-based definition to ‘‘total lipid fatty acids
expressed as triglycerides’’ [4], with the intent to measure caloric fatty acids. Solubility and size of
fatty acids affect their caloric values. This is important for products that take advantage of this, such
as Benefat=Salatrim, so these products would be examined on a case-by-case basis. Food products
containing sucrose polyesters would require special methodology to calculate caloric fatty acids.
Foods containing vinegar (~4.5% acetic acid) present a problem because they will be considered to
have 4.5% fat unless the definition is modified to exclude water-soluble fatty acids or the caloric
weighting for acetic acid is lowered [4].
Despite the problems with accepted definitions, a more precise working definition is difficult,
given the complexity and heterogene ity of lipids. This chapter introduces the main lipid structures
and their nomenclature.
II. LIPID CLASSIFICATIONS
Classification of lipid structures is possible based on physical properties at room temperature (oils
are liquid and fats are solid), their polarity (polar and neutral lipids), their essentiality for humans
(essential and nonessential fatty acids), or their structure (simple or complex). Neutral lipids include
fatty acids, alcohols, glycerides, and sterols, whereas polar lipids include glycerophospholipids and
glyceroglycolipids. The separation into polarity classes is rathe r arbitrary, as some short-chai n fatty
acids are very polar. A classification based on structure is, therefore, preferable.
Based on structure, lipids can be classified as derived, simple, or complex. The derived lipids

include fatty acids and alcohols, which are the building blocks for the simple and complex lipids.
Simple lipids, composed of fatty acids and alcohol components, include acylglycerols, ether
acylglycerols, sterols, and their esters and wax esters. In general terms, simple lipids can be
hydrolyzed to two different components, usually an alcohol and an acid. Complex lipids include
glycerophospholipids (phospholipids), glyceroglycolipids (glycolipids), and sphingolipids. These
structures yield three or more different compounds on hydrolysis.
The fatty acids constitute the obvious starting point in lipid structures. However, a short review
of standard nomenclature is appropriate. Over the years, a large number of different nomenclature
systems have been propos ed [5]. The resulting confusion has led to a need for nomenclature
standardization. The International Union of Pure and Applied Chemists (IUPAC) and International
Union of Biochemistry (IUB) collaborative efforts have resulted in comprehensi ve nomenclature
standards [6], and the nomenclature for lipids has been reported [7–9]. Only the main aspects of the
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4 Food Lipids: Chemistry, Nutrition, and Biotechnology
standardized IUPAC nomenclature relating to lipid structures will be presented; greater detail is
available elsewhere [7–9].
Standard rules for nomenclature must take into consideration the difficulty in maintaining strict
adherence to structure-based nomenclature and elimination of common terminology [5]. For
example, the compound known as vitamin K
1
can be described as 2-methyl-3-phytyl-1,4-naphtho-
quinone. Vitamin K
1
and many other trivial names have been included into standardized nomen-
clature to avoid confusion arising from long chemical names. Standard nomenclature rules will be
discussed in separate sections relating to various lipid compounds.
Fatty acid terminology is complicated by the existence of several different nomenclature
systems. The IUPAC nomenclature, comm on (trivial) names, and shorthand (n-orv) terminology
will be discussed. As a lipid class, the fatty acids are often called free fatty acids (FFAs) or
nonesterified fatty acids (NEFAs). IUPAC has recommended that fatty acids as a class be called

fatty acids and the terms FFA and NEFA eliminated [6].
A. STANDARD IUPAC NOMENCLATURE OF FATTY ACIDS
In standard IUPAC terminology [6], the fatty acid is named after the parent hydrocarbon. Table 1.1
lists common hydrocarbon names. For example, an 18-carbon carboxylic acid is called octadecanoic
acid, from octadecane, the 18-carbon aliphatic hydrocarbon. The name octadecanecarboxylic acid
may also be used, but it is more cumbersome and less common. Tab le 1.2 summarizes the rules for
hydrocarbon nomenclature.
Double bonds are designated using the D configuration, which represents the distance from the
carboxyl carbon, naming the carboxyl carbon number 1. A double bond between the ninth and tenth
carbons from the carboxylic acid group is a D9 bond. The hydrocarbon name is changed to indicate
the presence of the double bond; an 18-carbon fatty acid with one double bond is called octadece-
noic acid, one with two double bonds octadecadienoic acid, etc. The double-bond positions are
designated with numbers before the fatty acid name (D9-octadecenoic acid or simply 9-octadecenoic
acid). The D is assumed and often not placed explicitly in structures.
TABLE 1.1
Systematic Names of Hydroc arbons
Carbon Number Name Carbon Number Name
1n Methane 19 Nonadecane
2 Ethane 20 Eicosane
3 Propane 21 Henicosane
4 Butane 22 Docosane
5 Pentane 23 Tricosane
6 Hexane 24 Tetracosane
7 Heptane 25 Pentacosane
8 Octane 26 Hexacosane
9 Nonane 27 Heptacosane
10 Decane 28 Octacosane
11 Hendecane 29 Nonacosane
12 Dodecane 30 Triacontane
13 Tridecane 40 Tetracontane

14 Tetradecane 50 Pentacontane
15 Pentadecane 60 Hexacontane
16 Hexadecane 70 Heptacontane
17 Heptadecane 80 Octacontane
18 Octadecane
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Nomenclature and Classification of Lipids 5
Double-bond geometry is designated with the cis–trans or E=Z nomenclature systems [6]. The
cis=trans terms are used to describe the positions of atoms or groups connected to doubly bonded
atoms. They can also be used to indicate relative positions in ring structures. Atoms=groups are cis
or trans if they lie on same (cis) or opposite (trans) sides of a reference plane in the molecule. Some
examples are shown in Figure 1.1. The prefixes cis and trans can be abbreviated as c an d t in
structural formulas.
The cis=trans configuration rules are not applicable to double bonds that are terminal in a
structure or to double bonds that join rings to chains. For these conditions, a sequence preference
ordering must be conducted. Since cis=trans nomenclature is applicab le only in some cases, a new
nomenclature system was introduced by the Chemical Abstracts Service and subsequently adopted
by IUPAC (the E=Z nomenclature). This system was developed as a more applicable system to
describe isomers by using sequence ordering rules, as is done using the R=S system (rules to decide
which ligand has priority). The sequence rule-preferred atom=group attached to one of a pair of
doubly bonded carbon atoms is compared with the sequence rule-preferred atom=group of the other
of the doubly bonded carbon atoms. If the preferred atom=groups are on the same side of the
reference plane, it is the Z configuration. If they are on the opposite sides of the plane, it is the E
configuration. Table 1.3 summarizes some of the rules for sequence preference [10]. Although cis
and Z (or trans and E) do not always refer to the same configurations, for most fatty acids E and
trans are equivalent, as are Z and cis.
TABLE 1.2
IUPAC Rules for Hydrocarbon Nomenclature
1. Saturated unbranched acyclic hydrocarbons are named with a numerical prefix and the termination ‘‘ ane.’’ The first four in
this series use trivial prefix names (methane, ethane, propane, and butane), whereas the rest use prefixes that represent the

number of carbon atoms.
2. Saturated branched acyclic hydrocarbons are named by prefixing the side chain designation to the name of the longest
chain present in the structure.
3. The longest chain is numbered to give the lowest number possible to the side chains, irrespective of the substituents.
4. If more than two side chains are present, they can be cited either in alphabetical order or in order of increasing complexity.
5. If two or more side chains are present in equivalent positions, the one assigned the lowest number is cited first in the name.
Order can be based on alphabetical order or complexity.
6. Unsaturated unbranched acyclic hydrocarbons with one double bond have the ‘‘ane’’ replaced with ‘‘ene.’’ If there is more
than one double bond, the ‘‘ane’’ is replaced with ‘‘diene,’’ ‘‘triene,’’ ‘‘tetraene,’’ etc. The chain is numbered to give the
lowest possible number to the double bonds.
Source: From IUPAC in Nomenclature of Organic Chemistry, Sections A, B, C, D, E, F, and H, Pergamon Press, London,
1979, 182.
C C
a
b
C
b
a
C
a
ab
b
cis trans
cis trans
b
ba
a
a
bb
a

FIGURE 1.1 Examples of cis=trans nomenclature.
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6 Food Lipids: Chemistry, Nutrition, and Biotechnology
B. COMMON (TRIVIAL)NOMENCLATURE OF FATTY ACIDS
Common names have been introduced throughout the years and, for certain fatty acids, are a great
deal more common than standard (IUPAC) terminology. For example, oleic acid is much more
common than cis-9-octadecenoic acid. Common names for saturated and unsaturate d fatty acids are
illustrated in Tables 1.4 and 1.5. Many of the common names originate from the first identified
TABLE 1.3
Summary of Sequence Priority Rules for E=Z Nomenclature
1. Higher atomic number precedes lower.
2. For isotopes, higher atomic mass precedes lower.
3. If the atoms attached to one of the double-bonded carbons are the same, proceed outward concurrently until a point of
difference is reached considering atomic mass and atomic number.
4. Double bonds are treated as if each bonded atom is duplicated.
Source: From Streitwieser Jr., A. and Heathcock, C.H. in Introduction to Organic Chemistry, Macmillan, New York,
1976, 111.
TABLE 1.4
Systematic, Common, and Shorthand Names
of Saturated Fatty Acids
Systematic Name Common Name Shorthand
Methanoic Formic 1:0
Ethanoic Acetic 2:0
Propanoic Propionic 3:0
Butanoic Butyric 4:0
Pentanoic Valeric 5:0
Hexanoic Caproic 6:0
Heptanoic Enanthic 7:0
Octanoic Caprylic 8:0
Nonanoic Pelargonic 9:0

Decanoic Capric 10:0
Undecanoic — 11:0
Dodecanoic Lauric 12:0
Tridecanoic — 13:0
Tetradecanoic Myristic 14:0
Pentadecanoic — 15:0
Hexadecanoic Palmitic 16:0
Heptadecanoic Margaric 17:0
Octadecanoic Stearic 18:0
Nonadecanoic — 19:0
Eicosanoic Arachidic 20:0
Docosanoic Behenic 22:0
Tetracosanoic Lignoceric 24:0
Hexacosanoic Cerotic 26:0
Octacosanoic Montanic 28:0
Tricontanoic Melissic 30:0
Dotriacontanoic Lacceroic 32:0
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Nomenclature and Classification of Lipids 7
botanical or zoological origins for those fatty acids. Myristic acid is found in seed oils from the
Myristicaceae family. Mistakes have been memorialized into fatty acid common names; margaric
acid (heptadecanoic acid) was once incorrectly thought to be present in margarine. Some of the
common names can pose memorization difficulties, such as the following combinations: caproic,
caprylic, and capric; arachidic and arachidonic; linoleic, linolenic, g-linoleni c, and dihomo-g-
linolenic. Even more complicated is the naming of EPA, or eicosapentaenoic acid, usually meant
to refer to c-5,c-8,c-11,c-14,c-17-eicosapentaenoic acid, a fatty acid found in fish oils. However, a
different isomer c-2,c-5,c-8,c-11,c-14-eicosap entaenoic acid is also found in nature. Both can be
referred to as eicosapentaenoic acids using standard nomenclature. Nevertheless, in common
nomenclature, EPA refers to the c-5,c-8,c-11,c-14,c-17 isomer. Docosahexaenoic acid (DHA) refers
to all-cis 4,7,10,13,16,19-docosahexaenoic acid.

C. SHORTHAND (v)NOMENCLATURE OF FATTY ACIDS
Shorthand (n-orv) identifications of fatty acids are found in common usage. The shorthand
designation is the carbon number in the fatty acid chain followed by a colon, then the number of
double bonds and the position of the double bond closest to the methyl side of the fatty acid
TABLE 1.5
Systematic, Common, and Shorthand Names of Unsaturated Fatty Acids
Systematic Name Common Name Shorthand
c-9-Dodecenoic Lauroleic 12:1v3
c-5-Tetradecenoic Physeteric 14:1v9
c-9-Tetradecenoic Myristoleic 14:1v5
c-9-Hexadecenoic Palmitoleic 16:1v7
c-7,c-10,c-13-Hexadecatrienoic — 16:3v3
c-4,c-7,c-10,c-13-Hexadecatetraenoic — 16:4v3
c-9-Octadecenoic Oleic 18:1v9
c-11-Octadecenoic cis-Vaccenic (Asclepic) 18:1v7
t-11-Octadecenoic Vaccenic
a
t-9-Octadecenoic Elaidic
a
c-9,c-12-Octadecadienoic Linoleic 18:2v6
c-9-t-11-Octadecadienoic acid Rumenic
ba
c-9,c-12,c-15-Octadecatrienoic Linolenic 18:3v3
c-6,c-9,c-12-Octadecatrienoic g-Linolenic 18:3v6
c-6,c-9,c-12,c-15-Octadecatetraenoic Stearidonic 18:4v3
c-11-Eicosenoic Gondoic 20:1v9
c-9-Eicosenoic Gadoleic 20:1v11
c-8,c-11,c-14-Eicosatrienoic Dihomo-g-linolenic 20:3v6
c-5,c-8,c-11-Eicosatrienoic Mead’s 20:3v9
c-5,c-8,c-11,c-14-Eicosatetraenoic Arachidonic 20:4v6

c-5,c-8,c-11,c-14,c-17-Eicosapentaenoic Eicosapentaenoic 20:5v3
c-13-Docosenoic Erucic 22:1v9
c-11-Docosenoic Cetoleic 22:1v11
c-7,c-10,c-13,c-16,c-19-Docosapentaenoic DPA, Clupanodonic 22:5v3
c-4,c-7,c-10,c-13,c-16,c-19-Doc
osahexaenoic DHA, Cervonic 22:6v3
c-15-Tetracosenoic Nervonic (Selacholeic) 24:1v9
a
Shorthand nomenclature cannot be used to name trans fatty acids.
b
One of the conjugated linoleic acid (CLA) isomers.
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8 Food Lipids: Chemistry, Nutrition, and Biotechnology
molecule. The methyl group is number 1 (the last character in the Greek alphabet is v, hence the
end). In shorthand notation, the unsaturated fatty acids are assumed to have cis bonding and, if the
fatty acid is polyunsaturated, double bonds are in the methylene-interrupted positions (Figure 1.2).
In this example, CH
2
(methylene) groups at D8 and D11 interrupt what would otherwise be a
conjugated bond system.
Shorthand terminology cannot be used for fatty acids with trans or acetylene bonds, for those
with additional functional groups (branched, hydroxy, etc.), or for double-bond systems (2 double
bonds) that are not methylene interrupted (isolated or conjugated). Despite the limitations, shorthand
terminology is very popular because of its simplicity and because most of the fatty acids of
nutritional importance can be named. Sometimes the v is replaced by n- (18:2n-6 instead of
18:2v6). Although there have been recommendations to eliminate v and use n- exclusively [6],
both n- and v are commonly used in the literature and are equivalent.
Shorthand designations for polyunsaturated fatty acids (PUFAs) are sometimes reported without
the v term (18:3). However, this notation is ambiguous, since 18:3 could represent 18:3v1, 18:3v3,
18:3v6, or 18:3v9 fatty acids, which are completely different in their origins and nutritional

significances. Two or more fatty acids with the same carbon and double-bond numbers are possible
in many common oils. Therefore, the v terminology should always be used with the v term
specified.
III. LIPID CLASSES
A. F
ATTY ACIDS
1. Saturated Fatty Acids
The saturated fatty acids begin with methanoic (formic) acid. Methanoic, ethanoic, and propanoic
acids are uncommon in natural fats and are often omitted from definitions of lipids. However, they
are found nonesterified in many food products. Omitting these fatty acids because they are water
soluble would argue for also eliminating butyric acid, which would be difficult given its import-
ance in dairy fats. The simplest solution is to accept the very short-chain carboxylic acids as fatty
acids while acknowledging the rarity in natural fats of these water-soluble compounds. The
systematic, common, and shorthand designations of some saturated fatty acids are given in
Table 1.4.
HOOC
1
2
3
4
5
6
7
8
9
10
11
12
13
14

15
16
17
18
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
Outside of molecule ∆ numbering
Inside of molecule ω numbering
18:3cis-6,cis-9,cis-12
18:3ω6
FIGURE 1.2 IUPAC D and common v numbering systems.
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Nomenclature and Classification of Lipids 9
2. Unsaturated Fatty Acids

By far, the most common monounsaturated fatty acid is oleic acid (18:1v9), although more than 100
monounsaturated fatty acids have been identified in nature. The most common double-bond position
for monoenes is D9. However, certain families of plants have been shown to accum ulate what would
be considered unusual fatty acid patterns. For example, Eranthis seed oil contains D5 monoenes and
nonmethylene-interrupted PUFAs containing D5 bonds [11]. Erucic acid (22:1v9) is found at high
levels (40%–50%) in Cruciferae such as rapeseed and mustard seed. Canola is a rapeseed oil that is
low in erucic acid ( <2% 22:1v9).
PUFAs are best described in terms of families because of the metabolism that allows intercon-
version within, but not among, families of PUFA. The essentiality of v6 fatty acids has been known
since the late 1920s. Signs of v6 fatty acid deficiency include decreased growth, increased
epidermal water loss, impaired wound healing, and impaired reproduction [12,13]. Early studies
did not provide clear evidence that v 3 fatty acids are essential. However, since the 1970s, evidence
has accumulated illustrating the essentiality of the v3 PUFA.
Not all PUFAs are essential fatty acids (EFAs). Plants are able to synthesize de novo and
interconvert v3andv6 fatty acid families via desaturases with specificity in the D12 and D15
positions. Animals have D5, D6, and D9 desaturase enzymes and are unable to synthesize the v3
and v6 PUFAs de novo. However, extensive elongation and desaturation of EFA occurs (primarily
in the liver). The elongation and desaturation of 18:2v6 is illustrated in Figure 1.3. The most
common of the v6 fatty acids in our diets is 18:2v6. Often considered the parent of the v6 family,
18:2v6isfirst desaturated to 18:3v6. The rate of this first desaturation is thought to be limiting in
premature infants, in the elder ly, and under certain disease states. Thus, a great deal of interest has
been placed in the few oils that contain 18:3v6, g-linolenic acid (GLA). Relatively rich sources of
GLA include black currant, evening primrose , and borage oils. GLA is elongated to 20:3v6,
dihomo-g-linolenic acid (DHGLA). DHGLA is the precursor molecule to the 1-series prosta-
glandins. DHGLA is further desaturated to 20:4v6, precursor to the 2-series prostaglandins. Further
elongation and desaturation to 22:4 v6 and 22:5v6 can occur, although the exact function of these
fatty acids remains obscure. Relatively high levels of these fatty acids are found in caviar from wild
but not cultured sturgeon.
18:2ω6 Linoleic acid
∆-6-Desaturase

20:3ω6 Dihomo-γ-linolenic acid
18:3ω6 γ-Linolenic acid
20:4ω6 Arachidonic acid
Elongase
∆-5-Desaturase
COOH
COOH
COOH
COOH
FIGURE 1.3 Pathway of 18:2v6 metabolism to 20:4v6.
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10 Food Lipids: Chemistry, Nutrition, and Biotechnology
Figure 1.4 illustrates analogous elongation and desaturation of 18:3v3. The elongation of 20:5v3
to 22:5 v3 was thought for many years to be via D4 desaturase. The inexplicable difficulty in
identifying and isolating the putative D4 desaturase led to the conclusion that it did not exist, and the
pathway from 20:5v3 to 22:6v3 was elucidated as a double elongation, desaturation, and b-oxidation.
One of the main functions of the EFAs is their conversion to metabolically active prostaglandins
and leukotrienes [14,15]. Examples of some of the possible conversions from 20:4v6 are shown in
Figures 1.5 and 1.6 [15]. The prostaglandins are called eicosanoids as a class and originate from the
action of cyclooxygenase on 20:4v 6 to produce PGG
2
. The standard nomenclature of prosta-
glandins allows usage of the names presented in Figure 1.5. For a name such as PGG
2
, the PG
represents prostaglandin, the next letter (G) refers to its structure (Figure 1.7), and the subscript
number refers to the number of double bonds in the molecule.
The parent structure for most of the prostaglandins is prostanoic acid (Figure 1.7) [14]. Thus, the
prostaglandins can be named based on this parent structure. In addition, they can be named using
standard nomenclature rules. For example, prostaglandin E

2
(PGE
2
) is named (5Z,11a,13E,15S )-
11,15-dihydroxy-9-oxoprosta-5,13-dienoic acid using the prostanoic acid template. It can also be
named using standard nomenclature as 7-[3-hydroxy-2-(3-hydroxy-1-octenyl)-5-oxocyclopentyl]-
cis-5-heptenoic acid.
The leukotrienes are produced from 20:4v6 via 5-, 12-, or 15-lipoxygenases to a wide range of
metabolically active molecules. The nomenclature is shown in Figure 1.6.
It is important to realize that there are 1-, 2-, and 3-series prostaglandins originating from
20:3v6, 20:4v6, and 20:5v3, respectively. The structures of the 1-, 2-, and 3-prostaglandins differ
∆-6-Desaturase
20:4ω3
18:4ω3
18:3ω3 Linolenic acid
20:5ω3 Eicosapentaenoic
Elongase
∆-5-Desaturase
22:5ω3 Docosapentaenoic
22:6ω3 Docosahexaenoic
β-Oxidation
Elongase
Elongase
24:5ω3 Tetracosapentaenoic
24:6ω3 Tetracosahexaenoic
∆-6-Desaturase
COOH
COOH
COOH
COOH

COOH
COOH
COOH
COOH
FIGURE 1.4 Pathway of 18:3v3 metabolism to 22:6v3.
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Nomenclature and Classification of Lipids 11