Food Enrichment with Omega-3 Fatty Acids

Charlotte Jacobsen, Nina Skall Nielsen, Anna Frisenfeldt Horn, Ann-Dorit Moltke Sørensen

• Publisher: Woodhead Publishing
• Year: 2013
• Print ISBN:
  9780857094285
• eBook ISBN:
  9780857098863
• Topic: Technologie et ingénierie
• Subtopic: Sciences de l'alimentation

Omega-3 fatty acids provide many health benefits, from reducing cardiovascular disease to improving mental health, and consumer interest in foods enriched with omega-3 fatty acids is increasing. Formulating a product enriched with these fatty acids that is stable and has an acceptable flavour is challenging. Food enrichment with omega-3 fatty acids provides an overview of key topics in this area.Part one, an introductory section, reviews sources of omega-3 fatty acids and their health benefits. Chapters in part two explore the stabilisation of both fish oil itself and foods enriched with omega-3 fatty acids. Part three focuses on the fortification of different types of foods and beverages with omega-3 fatty acids, including meat products, by the modification of animal diets and other methods, infant formula and baked goods. Finally, part four highlights new directions in the field and discusses algal oil as a source of omega-3 fatty acids and labelling and claims in foods containing omega-3 fatty acids.Food enrichment with omega-3 fatty acids is a standard reference for professionals in the functional foods industry involved with research, development and quality assessment and for researchers in academia interested in food lipids, oxidation and functional foods. - Provides a comprehensive overview of formulating a product enriched with omega-3 fatty acids that is stable, provides many health benefits and has an acceptable flavour - Reviews sources of omega-3 fatty acids and their health benefits and explores the stabilisation of fish oil and foods enriched with omega-3 fatty acids - Focuses on the fortification of different types of foods and beverages with omega-3 fatty acids and highlights new directions in the field

Part I

Background to omega-3 food enrichment

1

Nutritional benefits of omega-3 fatty acids

P.C. Calder, University of Southampton, UK

Abstract:

This chapter describes nutritional and biochemical aspects of omega-3 (ω-3) fatty acids, their effects on outcomes related to human health and disease, and the underlying mechanisms of action. Both marine- and plant-derived omega-3 fatty acids are described. The chapter ends with a discussion of future trends for research in this area.

Key words

Fish

fish oil

eicosapentaenoic acid

docosahexaenoic acid

cardiovascular disease

omega-3 fatty acids

1.1 Introduction

This chapter describes nutritional and biochemical aspects of omega-3 (ω-3) fatty acids, their effects on outcomes related to human health and disease, and the underlying mechanisms of action. The chapter begins with a description of the structure, naming and metabolic relationships of the various omega-3 fatty acids. This is followed by an examination of the dietary sources of the major plant-derived omega-3 fatty acid, α-linolenic acid, and of the more biologically active fish-derived omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and of typical intakes of these fatty acids. The manner in which EPA and DHA are handled within the body is described as are the resulting concentrations in various sites. The impact of consuming preformed EPA and DHA (e.g. from fish oil supplements) on the contents of these fatty acids in various blood plasma and cell fractions is considered, followed by coverage of the main mechanisms by which these fatty acids can influence cellular behaviour and organ physiology. Next, the benefits of EPA and DHA to human development and health through the life cycle are described, leading to a discussion of current recommendations for intake of EPA and DHA. Then, the health effects of α-linolenic acid are reviewed briefly as is the evidence for conversion of α-linolenic acid to EPA and DHA in humans. The chapter ends with a summary and conclusions section followed by a discussion of future trends.

1.1.1 Structure, naming and metabolic relationships of omega-3 fatty acids

The term omega-3 (also notated as ω-3 or n-3) is a structural descriptor for a family of polyunsaturated fatty acids (PUFA): it denotes the position of the double bond that is closest to the methyl terminus of the acyl chain of the fatty acid. All omega-3 fatty acids have this double bond on carbon 3, counting the methyl carbon as carbon 1 (Fig. 1.1). In common with all fatty acids, omega-3 fatty acids have systematic and common names (Table 1.1). However, they are also referred to by a shorthand nomenclature that denotes the number of carbon atoms in the chain, the number of double bonds and the position of the first double bond relative to the methyl carbon (Table 1.1). Thus α-linolenic acid (18:3 ω-3) is the simplest omega-3 fatty acid. α-Linolenic acid is synthesised from linoleic acid (18:2 ω-6) by desaturation, catalysed by Δ¹⁵ desaturase (the desaturase enzymes are named according to the first carbon carrying the newly inserted double bond and counting the carboxyl carbon as carbon number one). Like other animals, humans do not possess the Δ¹⁵ desaturase enzyme and so cannot synthesise α-linolenic acid de novo. It is for this reason that α-lino-lenic acid is considered to be an essential fatty acid. The other classically essential fatty acid is linoleic acid. Because plants possess Δ¹⁵ desaturase they can synthesise α-linolenic acid (Fig. 1.2). Although they cannot synthesise α-linolenic acid, animals can metabolise it by further desaturation and elongation; desaturation occurs at carbon atoms below carbon number 9 (counting from the carboxyl carbon) and mainly occurs in the liver. Through this pathway, α-linolenic acid is converted to stearidonic acid (18:4 ω-3) by Δ⁶ desaturase and then stearidonic acid is elongated to eicosatetraenoic acid (20:4 ω-3), which is further desaturated by Δ⁵ desaturase to yield EPA (20:5 ω-3) (Fig. 1.2). It is important to note that this pathway of conversion of α-linolenic acid to EPA is in direct competition with the conversion of linoleic acid to arachidonic acid (20:4 ω-6) since the same enzymes are used. The Δ⁶ desaturase reaction is the rate-limiting step in this pathway and, because linoleic acid is much more prevalent in most human diets than α-linolenic acid, metabolism of omega-6 fatty acids is quantitatively the more important.

Table 1.1

The omega-3 polyunsaturated fatty acid family

Systematic name	Common name	Shorthand nomenclature
all-cis-9,12, 15-Octadecatrienoic acid	α-Linolenic acid	18:3 ω-3
all-cis-6,9,12, 15-Octadecatetraenoic acid	Stearidonic acid	18:4 ω-3
all-cis-8,11,14, 17-Eicosatetraenoic acid	Eicosatetraenoic acid	20:4 ω-3
all-cis-5,8,11,14, 17-Eicosapentaenoic acid	Eicosapentaenoic acid	20:5 ω-3
all-cis-7,10,13,16, 19-Docosapentaenoic acid	Docosapentaenoic acid; also clupanodonic acid	22:5 ω-3
all-cis-4,7,10,13,16, 19-Docosahexaenoic acid	Docosahexaenoic acid	22:6 ω-3

1.1 Generic structure of omega-3 fatty acids. R indicates the continuation of the acyl chain terminating to the carboxyl group.

1.2 Pathway of conversion of linoleic acid to α-linolenic acid and of α-linolenic acid to longer chain, more unsaturated omega-3 fatty acids.

There is a pathway for conversion of EPA to DHA (22:6 ω-3) (Fig. 1.2). This rather complex pathway involves a...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Contributor contact details
• Woodhead Publishing Series in Food Science, Technology and Nutrition
• Preface
• Part I: Background to omega-3 food enrichment
• Part II: Stabilisation of fish oil and foods enriched with omega-3 fatty acids
• Part III: Food enrichment with omega-3 fatty acids
• Part IV: New directions
• Index