Milk Proteins: From Expression to Food

By Academic Press

Understanding of the interactions of milk proteins in complex food systems continues to progress, resulting in specialized milk-protein based applications in functional foods, and in protein ingredients for specific health applications. Milk Proteins is the first and only presentation of the entire dairy food chain – from the source to the nutritional aspects affecting the consumer.

With focus on the molecular structures and interactions of milk proteins in various processing methods, Milk Proteins presents a comprehensive overview of the biology and chemistry of milk, as well as featuring the latest science and developments. Significant insight into the use of milk proteins from an industry viewpoint provides valuable application-based information. Those working with food and nutritional research and product development will find this book useful.

• 20% new chapter content — full revision throughout
• New chapters address: role of milk proteins in human health; aspects of digestion and absorption of milk proteins in the GIT; consumer demand and future trends in milk proteins; and world supply of proteins with a focus on dairy proteins
• Internationally recognized authors and editors bring academic and industrial insights to this important topic

• Language: English
• Publisher: Academic Press
• Release date: Jul 8, 2014
• ISBN: 9780124051751

Book preview

Milk Proteins

From Expression to Food

Second edition

Harjinder Singh

Mike Boland

Abby Thompson

Riddet Institute, Massey University, Palmerston North, New Zealand

Table of Contents

Cover

Title page

Food Science and Technology International Series

Copyright

List of Contributors

Preface to the Second Edition

Preface to the First Edition

Chapter 1: The World Supply of Food and the Role of Dairy Protein

Abstract

Introduction

Hunger and the need for food

The dietary essential amino acids in proteins

Identifying the countries deficient in dietary essential amino acids

Demographic changes, aging populations, and the need for quality protein and essential amino acids

Global trade in proteins, the long-term prospects, with a focus on dairy foods

Conclusions

Chapter 2: Milk: An Overview

Abstract

Introduction

Evolution of mammals and lactation

Utilization of milk

Composition of milk

Milk constituents

Summary

Chapter 3: The Comparative Genomics of Monotremes, Marsupials, and Pinnipeds: Models to Examine the Functions of Milk Proteins

Abstract

Introduction

The echidna (Tachyglossus aculeatus)

The tammar wallaby (Macropus eugenii)

A role for milk in the control of mammary function

The fur seal

New player in milk bioactives; MicroRNA

Conclusions

Chapter 4: Significance, Origin, and Function of Bovine Milk Proteins: The Biological Implications of Manipulation or Modification

Abstract

Introduction

Origins of milk proteins

Constraints and opportunities for evolution or manipulation of bovine milk proteins

Conclusion

Chapter 5: Post-translational Modifications of Caseins

Abstract

Introduction

The caseins

Caseins from other species

Conclusions

Chapter 6: Casein Micelle Structure and Stability

Abstract

Introduction

Casein primary structure and interactions

Casein micelle properties

Models of casein micelle structure

Concluding remarks

Chapter 7: Structure and Stability of Whey Proteins

Abstract

Introduction

Bovine β-Lactoglobulin

α-Lactalbumin

Serum albumin

Immunoglobulins

Lactoferrin

Concluding remarks

Acknowledgments

Chapter 8: Effects of High-pressure Processing on Structure and Interactions of Milk Proteins

Abstract

Introduction

High-pressure-induced changes in caseins

Effects of high pressure on interactions of milk proteins involving whey proteins

Concluding remarks

Acknowledgment

Chapter 9: The Whey Proteins in Milk: Thermal Denaturation, Physical Interactions, and Effects on the Functional Properties of Milk

Abstract

Introduction

The casein micelle

The heat treatment of milk

Relationships between denaturation/interactions of the whey proteins in heated milk and the functional properties of milk

Conclusion

Chapter 10: Effects of Drying on Milk Proteins

Abstract

Introduction

Properties of spray-dried milk products

Principles of spray drying

Process improvement

Drying of proteins

Conclusions

Chapter 11: Changes in Milk Proteins during Storage of Dry Powders

Abstract

Introduction

The formation of maillard and pre-maillard compounds

Formation of isopeptide bonds

Amino acids other than lysine

Implications for nutritional value of milk proteins

Product-specific storage trials

Conclusions

Chapter 12: Interactions and Functionality of Milk Proteins in Food Emulsions

Abstract

Introduction

Adsorption of Milk Proteins During the Formation of Emulsions

Stability of Milk Protein-Based Emulsions

Heat-Induced Changes in Milk Protein-Based Emulsions

Pressure-Induced Changes in Milk Protein-Based Emulsions

Milk Protein Hydrolysates and Oil-In-Water Emulsions

Lactoferrin-Based Oil-In-Water Emulsions

Lipid Oxidation in Milk Protein-Based Emulsions

Behavior of Milk Protein-Stabilized Emulsions Under Physiological Conditions

Conclusions

Chapter 13: Milk Protein–Polysaccharide Interactions

Abstract

Introduction

Mixing behavior of biopolymers

Phase diagram

Nature of interactions in protein–polysaccharide systems

Milk protein–polysaccharide interactions in the aqueous phase

Milk protein–polysaccharide interactions at the interface

Rheological properties and microstructures of protein–polysaccharide systems

Concluding remarks

Chapter 14: Interactions between Milk Proteins and Micronutrients

Abstract

Introduction

Interactions Between native Milk Proteins and Micronutrients

Interactions between process-modified milk proteins and micronutrients

Conclusions

Chapter 15: Model Food Systems and Protein Functionality

Abstract

Introduction

Protein functionality in foods

Role of interactions in determining food characteristics

Processing effects

Uses of model food systems

Applications of model food systems

Use of model food systems for other food components

Limitations

Conclusions

Chapter 16: Sensory Properties of Dairy Proteins

Abstract

Introduction

Sensory analysis

Whey proteins

Milk proteins

Caseins and hydrolysates

Flavor binding

Conclusions

Acknowledgment

Chapter 17: Milk Protein Gels

Abstract

Introduction

Rennet-induced gels

Acid-induced milk gels

Whey protein gels

Conclusions

Acknowledgment

Chapter 18: Milk Proteins—A Cornucopia for Developing Functional Foods

Abstract

Introduction

Functional foods

Milk proteins as a source of amino acids—specialized nutritionals

Milk proteins as a source of amino acids—specific physiological roles

Milk proteins as a source of amino acids—role in providing calories and in promoting satiety

Milk proteins as a source of bioactive peptides

Conclusions

Chapter 19: Milk Proteins and Human Health

Abstract

Introduction

Milk proteins, metabolic health, and type 2 diabetes

Milk proteins, obesity, and weight control

Milk proteins and bone health

Conclusions

Chapter 20: Milk Proteins: Digestion and Absorption in the Gastrointestinal Tract

Abstract

Introduction

Digestion of milk proteins

Milk protein hydrolysis in the intestinal lumen

Peptides released during digestion

Impact of processing on milk protein digestion and absorption

Conclusions

Chapter 21: Milk Proteins: The Future

Abstract

Introduction

Global issues for food

Consumer demands and trends for food and ingredients

New technologies and their possible effect on milk protein ingredients and products

Conclusions

Index

Food Science and Technology: International Series

Food Science and Technology International Series

Series Editor

Steve L. Taylor

University of Nebraska—Lincoln, USA

Advisory Board

Ken Buckle

The University of New South Wales, Australia

Mary Ellen Camire

University of Maine, USA

Roger Clemens

University of Southern California, USA

Hildegarde Heymann

University of California—Davis, USA

Robert Hutkins

University of Nebraska—Lincoln, USA

Ron S. Jackson

Quebec, Canada

Huub Lelieveld

Bilthoven, The Netherlands

Daryl B. Lund

University of Wisconsin, USA

Connie Weaver

Purdue University, USA

Ron Wrolstad

Oregon State University, USA

A complete list of books in this series appears at the end of this volume.

Copyright

Academic Press is an imprint of Elsevier

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ISBN : 978-0-12-405171-3

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List of Contributors

Skelte G. Anema

Fonterra Research and Development Centre, Palmerston North, New Zealand

S.D. Berry

School of Population Health, University of Auckland, Auckland, New Zealand

Swathi Bisana

School of Medicine, Deakin University, Geelong, Victoria, Australia

Mike J. Boland

Riddet Institute, Massey University, Palmerston North, New Zealand

Srikanta Chatterjee

Massey University, Palmerston North, New Zealand

Rod Collins

School of Medicine, Deakin University, Geelong, Victoria, Australia

Thérèse Considine

Fonterra Research and Development Centre, Palmerston North, New Zealand

M. Digby

Department of Zoology and CRC for Innovative Dairy Products, University of Melbourne, Victoria, Australia

M.A. Drake

Department of Food Science, Southeast Dairy Foods Research Center, North Carolina State University, Raleigh, North Carolina, USA

Didier Dupont

UMR 1253 INRA, Rennes, France

Patrick J.B. Edwards

Centre for Structural Biology, Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand

John Flanagan

Riddet Institute, Massey University, Palmerston North, New Zealand; Naturex S.A., Avignon Cedex, France

P.F. Fox

School of Food and Nutritional Sciences, University College, Cork, Ireland

Kelvin K.T. Goh

Institute of Food, Nutrition and Human Health, Massey University, Palmerston North, New Zealand

W. James Harper

Department of Food Science and Technology, The Ohio State University, Columbus, Ohio, USA

Kerianne Higgs

Fonterra Research and Development Centre, Palmerston North, New Zealand

John W. Holland

Institute for Molecular Bioscience, The University of Queensland, Australia

David S. Horne

Formerly Hannah Research Institute, Ayr, Scotland, UK

Thom Huppertz

NIZO Food Research BV, Ede, The Netherlands

Geoffrey B. Jameson

Centre for Structural Biology, Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand

Amit Kumar

School of Medicine, Deakin University, Geelong, Victoria, Australia

Joly Kwek

School of Medicine, Deakin University, Geelong, Victoria, Australia

Christophe Lefevre

School of Medicine, Deakin University, Geelong, Victoria, Australia

Simon M. Loveday

Riddet Institute, Massey University, Palmerston North, New Zealand

John A. Lucey

Department of Food Science, University of Wisconsin-Madison, Madison, Wisconsin, USA

Robin A. McGregor

Human Nutrition Unit, Institute for Innovation in Biotechnology, School of Biological Sciences, University of Auckland, Auckland, New Zealand

K. Menzies

Department of Zoology and CRC for Innovative Dairy Products, University of Melbourne, Victoria, Australia

R.E. Miracle

Department of Food Science, Southeast Dairy Foods Research Center, North Carolina State University, Raleigh, North Carolina, USA

Vengama Modepalli

School of Medicine, Deakin University, Geelong, Victoria, Australia

Paul J. Moughan

Riddet Institute, Massey University, Palmerston North, New Zealand

Kevin R. Nicholas

School of Medicine, Deakin University, Geelong, Victoria, Australia; Victorian Bioinformatics Consortium, Monash University, Clayton, Victoria, Australia

J.A. O’Mahony

School of Food and Nutritional Sciences, University College, Cork, Ireland

Hasmukh A. Patel

Dairy Science Department, South Dakota State University, South Dakota, USA

Sally D. Poppitt

Human Nutrition Unit, Institute for Innovation in Biotechnology, School of Biological Sciences, University of Auckland, Auckland, New Zealand; Riddet Institute, Massey University, Palmerston North, New Zealand

Anwesha Sarkar

Nestec Ltd., Vevey, Switzerland

Arnab Sarkar

Synlait Milk Ltd., Rakaia, New Zealand

Pierre Schuck

INRA, UMR 1253, STLO, Rennes, France

Julie A. Sharp

School of Medicine, Deakin University, Geelong, Victoria, Australia

P.A. Sheehy

Centre for Advanced Technologies in Animal Genetics and Reproduction (REPROGEN), Faculty of Veterinary Science, The University of Sydney, Camden, New South Wales, Australia

Harjinder Singh

Riddet Institute, Massey University, Palmerston North, New Zealand

R.G. Snell

School of Biological Sciences, University of Auckland, Auckland, New Zealand

Daniel Tome

UMR 914 INRA, Paris, France

Stephen Wanyonyi

School of Medicine, Deakin University, Geelong, Victoria, Australia

Ashalyn Watt

School of Medicine, Deakin University, Geelong, Victoria, Australia

P. Williamson

Centre for Advanced Technologies in Animal Genetics and Reproduction (REPROGEN), Faculty of Veterinary Science, The University of Sydney, Camden, New South Wales, Australia

J.M. Wright

Department of Food Science, Southeast Dairy Foods Research Center, North Carolina State University, Raleigh, North Carolina, USA

P.C. Wynn

Centre for Advanced Technologies in Animal Genetics and Reproduction (REPROGEN), Faculty of Veterinary Science, The University of Sydney, Camden, New South Wales, Australia

Aiqian Ye

Riddet Institute, Massey University, Palmerston North, New Zealand

Preface to the Second Edition

It is now five years since the first edition of Milk Proteins: From Expression to Food was published. In that time there have been considerable advances in the topics covered in the first edition. There is new awareness both of the importance of proteins in nutrition globally and of a burgeoning demand for animal-derived protein on a global scale, coupled with a recognition of the higher resource demands for producing proteins from animals in comparison with plant proteins. New knowledge is emerging on the roles of milk proteins in the prevention of chronic age-related conditions such as adverse metabolic health and type 2 diabetes, muscle wasting and sarcopenia, atherosclerosis, hypertension, and cardiovascular disease risk, as well as bone health and osteoporosis. Understanding the digestion of proteins and how processing can influence digestion kinetics is another emerging area, supported by the emergent science of peptidomics. Because of these changing research interests, three new chapters have been added to this volume, and several other chapters have been extensively expanded and rewritten. All chapters have been considerably revised and updated. Because not all of the original authors were available, some new authors came aboard to rewrite and update the chapters.

Like the first edition, this book provides a comprehensive overview of the biology and chemistry of milk proteins and is intended for academics, researchers, students, and industry personnel interested in milk proteins. We would like to express our sincere appreciation to all the authors, in particular the new authors, for sharing their knowledge and expertise. Their cooperation and timely delivery of manuscripts made our task as editors a pleasure. Finally, we would like to thank the excellent staff at Elsevier, particularly Nancy Maragioglio, Carrie Bolger, and Caroline Johnson for their efforts in making this volume a reality.

Harjinder Singh

Abby Thompson

Mike Boland

February 2014.

Preface to the First Edition

Proteins are vital ingredients for the food industry because they provide all the essential amino acids needed for human health combined with a wide range of dynamic functional properties, such as the capacity to form network structures and stabilize emulsions and foams. The proteins of milk have excellent functional properties and nutritional value, and some have distinctive physiological properties, which are widely exploited in the food industry. Milk proteins have been the subject of intensive research during the last 50 years in an effort to unravel their molecular structures and interactions, relationship between structure and functional attributes, interactions of proteins during processing and, more recently, their physiological functions.

Recent studies on the interactions of milk proteins in complex food systems are leading to a new understanding of the nature of these interactions and their impact on food quality. The knowledge has resulted in the development of several specialized milk protein ingredients tailored to meet specific needs of the food industry. Currently, there is a growing demand by the food industry for milk protein ingredients for specialist high-value applications such as functional foods. In the future, application of novel analytical approaches (genomics, proteomics, nanotechnology) to milk proteins and food materials will provide further understanding of molecular structures and interactions to enable the dairy industry to produce highly functional and healthy protein ingredients for specific applications.

Several books have been published about milk and milk proteins—so why another one? Most of the earlier books have addressed different specialist aspects of dairy science and technology. The primary theme of this book is to present a view along the dairy food chain—starting at the cow (and its mammalian relatives) and finishing with nutritional aspects affecting the consumer, dipping into important current research topics along the way. The molecular structures and interactions of milk proteins under various processing environments are covered most prominently. More importantly, the book also contains a considerable amount of material from dairy industry-based or industry-funded research. Thus, it provides fresh perspectives on milk proteins, from an advanced dairy industry point of view.

The editors particularly thank Fonterra Research and Development Centre for making available time for staff members to contribute their chapters, and for making available hitherto unpublished material. This book is designed to provide an update and call for attention, for industry and academic researchers alike, to important and relevant milk protein science in areas that have the potential to advance the dairy industry.

The overall theme covered in this book was piloted at a meeting organized by the Riddet Institute and Fonterra Research and Development Centre in February 2006, with invited presentations from a number of experts in the relevant fields from Australasia, the USA and the UK. This meeting was particularly successful, with a large number of international delegates attending from a broad range of disciplines. This confirmed the growing interest of milk protein scientists in looking beyond the boundaries of their immediate topic area to gain an understanding of how the whole food chain fits together. Such an understanding can help elucidate mechanisms and processes, identify novel research opportunities, and provide additional applications for new developments.

This book includes chapters covering many of the topics addressed at the meeting, as well as some new subjects that we felt were important in order to provide a more complete picture of the journey from expression to food. We would like to thank both the contributors who have been involved from the meeting in 2006 and those who have come on board more recently.

We have chosen to start the book with a comprehensive overview of the biology and chemistry of milk, to set the stage and give a broad underpinning of the later chapters for readers not familiar with this field. Attention is then turned to the biology, and particularly the molecular biology, of lactation, looking first at some extreme mammals—the tammar wallaby, which can express two different milk compositions at the same time, and the fur seal, which produces an extremely concentrated milk—to give an idea of the range of biology of milk production. The book thereafter focuses on bovine milk, with mention of the milk from other domestic species as appropriate. This starts with an update on the genomics of bovine milk proteins, and is followed by an overview on post-translational modifications, which completes our view of the biology of milk protein production.

The structural chemistry of milk proteins, including the latest model of casein micelle and molecular structures of whey proteins, is covered in detail. The behavior of milk proteins under a variety of processing regimes, including ultra-high-pressure, functional systems, drying and storage of powders, is dealt with in a series of chapters. These chapters address our current state of knowledge about existing and emerging processes for the production of milk protein-based food ingredients.

Attention is then turned to the behaviors of milk proteins in real and model food systems, and finally to consumer aspects—the sensory and nutritional/functional food aspects of milk proteins. A wrap-up chapter gives a view on likely issues of future importance for milk proteins, including the emerging area of nutrigenomics.

As with any volume written by a large number of contributors, this contains a variety of styles of presentation. We have made no attempt to homogenize the authors’ styles, but have provided guidance on chapter content to make for best possible continuity.

A volume of this kind always requires a large amount of work by a large number of people. We would like particularly to thank all the contributing authors for their efforts and their expeditious preparation of manuscripts that allowed for the timely publication of this book. We are pleased to acknowledge Claire Woodhall for assisting with the technical editing, and the staff at Elsevier for producing this book.

Abby Thompson

Mike Boland

Harjinder Singh

Chapter 1

The World Supply of Food and the Role of Dairy Protein

Srikanta Chatterjee*

Arnab Sarkar**

Mike J. Boland***

*     Massey University, Palmerston North, New Zealand

**     Synlait Milk Ltd., Rakaia, New Zealand

***     Riddet Institute, Palmerston North, New Zealand

Abstract

World hunger continues to be a major problem. The main focus of those concerned with world hunger is on the availability of adequate calories for all, but this overshadows another problem: the availability of enough protein and enough dietary essential amino acids. We estimate that about a quarter of the world's population is getting barely enough protein; a particular issue is that of the essential amino acid lysine, which is deficient in cereal proteins, the biggest source of protein nutrition. Milk protein is an important source of dietary protein and is particularly rich in lysine and branched-chain amino acids. It accounts for 10% of all the global protein supply and provides the third highest supply after cereals and meat, but it is more important than the amounts would suggest because of its rich supply of essential amino acids and high digestibility (in contrast to cereal protein) and because of its acceptability to vegetarians. Global trade in dairy is still small (about 8% of dairy production is traded) but growing. Supplementation of cereal protein with milk protein has a potentially important role to play in balancing world protein nutrition.

Keywords

Protein nutrition, milk protein, dairy trade, dairy production

Outline

Introduction 2

Hunger and the need for food 3

Hunger-reduction Targets 3

World Hunger and Undernutrition Status 4

Global Hunger Index 4

Protein and Its Composition and Bioavailability 6

Protein Composition 6

Bioavailability 6

World Protein Supply and Its Regional Distribution 7

Vegetable and Animal Protein Sources with a Focus on Dairy Foods 8

Growing Global Demand for Animal Proteins and Implications 8

The dietary essential amino acids in proteins 9

Identifying the countries deficient in dietary essential amino acids 9

Protein and Dietary Essential Amino Acid Contents of Food Items 10

Demographic changes, aging populations, and the need for quality protein and essential amino acids 10

Protein Nutritional Needs of the Elderly 12

Role of Essential Amino Acids in Nutrition of the Elderly 13

Global trade in proteins, the long-term prospects, with a focus on dairy foods 14

The Global Dairy Food Scene: An Overview 14

Conclusions 16

Introduction

As one of the basic necessities of life, the availability, quality, and affordability of food are of concern to individuals and nations alike. The Green Revolution started in the late 1960s and involved the introduction of some new, high-yielding seed varieties, better use of irrigation facilities, and fertilizers. Following these innovations, the world enjoyed several decades of relative stability in the price of basic items of food, including food grains. The period from the early 1970s to 1990 saw world output of food grains and oilseeds rise steadily by an average of 2.2% a year, with periodic fluctuations. With the exception of parts of the African continent, the global rate of growth of food crops exceeded that of the world population, leading to an increase in their per capita availability and to relatively stable prices. Indeed, in 2000 world food prices in real terms were at their lowest for one hundred years (Trostle, 2008).

Since the early 1990s, however, the global rate of growth for grain and oilseed production has declined to 1.3% a year and is projected to decline further to around 1.2% over the next decade. This and a few other adverse factors have contributed to the rapid rise in the world market prices for major food products since early 2006, recording an increase of around 60% in just two years to early 2008. This upward trend has moderated somewhat since then, and the inflation-adjusted food price index stood at 140.3 in June 2013, having risen from its 2002–2004 base of 100.0. The most recent figures indicate that the Food and Agriculture Organization (FAO) food price index (FFPI) averaged 210 points in February 2013, remaining virtually stable since November 2012. The index of cereal prices, at 246 points, was 5.4% higher in June 2013 than it was a year earlier. The index of cereal prices was 5 points (2.07%) higher, and the index of dairy prices, after a sharp decline (22%) in the year to June 2012, rose 38% by June 2013 (FAO, 2013a). The general climate of rising retail prices of food items globally has raised the specter of another global food crisis, especially in the poorer countries, where the drive for food security has suffered a major jolt.

Side by side with this worsening situation with respect to the availabilities and prices of the major cereals, there has been another recent development involving food consumption patterns in a number of countries. With growing affluence, tastes change and consumers shift to more varied diets, which usually include larger proportions of noncereal items. Over the last few decades, several poorer countries, among them the two most populous ones, China and India, have experienced rapid growth and transformation in their economies. This economic growth has helped to lift several million people out of extreme poverty and to make many others more affluent, bringing in its trail significant changes in food consumption. One of the more noticeable changes has been a decline in the consumption of cereals and a corresponding increase in the consumption of animal protein. These developments have important policy implications for the global food economy. At the same time, hunger still afflicts a large number of people globally and there is a need for policies to resolve or mitigate this.

In light of these ongoing changes, this chapter seeks to examine several interrelated issues relating to the evolving world food situation. In particular, it investigates the issue of nutrition and the role proteins and their constituent amino acids play in it. It starts by looking at the issue of hunger, its measurement, global incidence, and mitigation targets. It next discusses the issue of nutrition, its global and regional perspectives, and the role of animal and vegetable proteins. The evolving global demographic trends, with a rapidly increasing elderly population that has special nutritional needs, call for policies to deal with the issue of nutrition for the aged and the role of proteins. Since the production and consumption of protein foods in different countries do not always match, significant international trade in protein products exists. This is briefly discussed to identify the major players in the global protein markets. The chapter concludes with observations on policy implications. In examining the various dimensions of proteins, this chapter focuses on the evolving role of dairy proteins and its implications for future policy.

Hunger and the need for food

Every day, millions of people around the globe do not get enough food to eat and remain hungry. Hunger has been referred to as the uneasy or painful sensation caused by a lack of food and the recurrent and involuntary lack of access to food (Anderson, 1990). There is no assurance that these hungry people will get the minimum required quantity of food on a daily basis. This unpredictability about where the next meal will come from is called food insecurity. The FAO of the United Nations defines food insecurity as a situation that exists when people lack secure access to sufficient amounts of safe and nutritious food for normal growth and development and an active and healthy life (FAO, 2000).

According to this definition, people are hungry if they do not get enough energy supply from food (fewer than about 1800 kilocalories a day), or if the food they consume is not of sufficiently high quality (i.e., does not contain essential nutrients). Hunger is usually understood to refer to the discomfort associated with lack of food (von Grebmer et al., 2012).

Hunger-Reduction Targets

Having thus defined hunger as an operational concept, we need to measure it and to track how it changes over time. This is probably better achieved if a target or targets are set, and the observed incidences of hunger are measured against those targets to ascertain whether the observed trends indicate an improvement or a deterioration.

The FAO currently monitors two main hunger-reduction targets: the World Food Summit target and Goal 1 of the Millennium Development Goals.

• During the World Food Summit in Rome (1996), world leaders made the commitment to decrease the number of undernourished people to around 425 million by 2015 (considering 850 million undernourished people as the baseline during the period 1990–1992) (FAO, 2011).

• At the 2000 Millennium Summit in New York, this objective was reiterated when the eight Millennium Development Goals were introduced. The first goal pertains directly to hunger, which is the FAO's fundamental global concern. It aims to reduce the number of people suffering from hunger between 1990 and 2015.

Goal 1 of the Millennium Development Goals calls for a reduction by half of the proportion of people suffering from hunger between 1990 and 2015. Rather than setting a definite number to be reached, this hunger objective therefore depends on the size of the future world population (FAO, 2011; United Nations 2010).

World Hunger and Undernutrition Status

According to the most recent FAO report, the total number of undernourished people in the world was estimated to be 1023 million in 2009, and it was projected to decrease by 9.6% to 925 million in 2010. The largest numbers of undernourished people live in the developing countries. Two-thirds live in just seven countries (Bangladesh, China, the Democratic Republic of the Congo, Ethiopia, India, Indonesia, and Pakistan), and over 40% live in China and India alone (FAO, WFP, and IFAD, 2012).The territory with the world's largest number of undernourished people continues to be Asia and the Pacific, with an estimated 578 million (Fig. 1.1).

Figure 1.1 Undernourishment in 2012, by region (millions). Data from FAO, WFP, and IFAD (2012).

Global Hunger Index

The International Food Policy Research Institute (IFPRI) has introduced the Global Hunger Index (GHI) tool to measure and track global hunger. The index combines three hunger indicators: (1) the number of undernourished as a proportion of the total population; (2) the proportion of underweight children under the age of 5; and (3) the mortality rate of children under the age of 5. The three indicators are assigned equal weights. On a 100-point scale, the higher the value of the index, the worse is the incidence of hunger, implying that a score of 0 indicates no hunger and a score of 100 indicates the worst possible hunger. Both of these extremes are, obviously, just notional, and are not observed in practice. Different hunger scenarios are defined with the help of the GHI. An index value less than 4.9 indicates low hunger; values of 5 to 9.9 moderate hunger; 10 to 19.9 serious hunger; 20 to 29.9 alarming hunger; and values in excess of 30 extremely alarming hunger.

The 2010 GHI showed some improvement over the 1990 value, falling from 19.8 to 15.1. The index fell by 14% in Sub-Saharan Africa; about 25% in South Asia; 33% in the Near East and North Africa; 40% in Southeast Asia; and 43% in Latin America and the Caribbean compared with the 1990 score (von Grebmer et al., 2012). Figure 1.2 graphs these values for the different regions.

Figure 1.2 Global and regional trends of the Global Hunger Index: Contribution of components in 1990, 1996, 2001, and 2012. Reproduced with permission from the International Food Policy Research Institute www.ifpri.org. The publication from which this figure originates can be found online at http://www.ifpri.org/sites/default/files/publications/ghi12.pdf.

THE IMPORTANCE OF PROTEIN IN WORLD NUTRITION

Most reports on hunger and undernutrition focus primarily on calories, and rightly so. If a person does not get enough calories, his or her well-being will be compromised. However, calories are a necessary, but not sufficient, condition for good nutrition. Many micronutrients, such as vitamins and minerals, are also an important part of the diet, but they are not the focus of this discussion.

A further aspect of undernutrition involves people not getting enough protein, and particularly a sufficient amount of the dietary essential amino acids. This aspect of undernutrition, as well as the role of dairy protein in meeting these needs, is the major concern of the rest of this chapter. Table 1.1 lists the recommended daily intake of protein and of the dietary essential amino acids. Adequate intake of total protein and of all the essential amino acids is essential to maintaining health.

Table 1.1

Recommended Daily Intake for Adults of Protein and Dietary Essential Amino Acids

Data from WHO (2007).

Protein and Its Composition and Bioavailability

The assessment of protein nutrition is more complex than that for calories because proteins vary widely in terms of their composition and bioavailability.

Protein Composition

All proteins are composed of linear chains of amino acids, and each species of protein has its own defined amino acid sequence, which is determined by the genetics of the producing organism. Thus, the amino acid composition, and by implication the amount of each essential amino acid in a given protein, are defined. In practice, most food protein sources contain a complex mixture of proteins. Nevertheless, the overall composition can be determined empirically and is generally quite constant. This has enabled the composition of almost all the major food protein sources in terms of essential amino acids to be determined, and thus intakes of dietary essential amino acids can be estimated from knowledge of the types and amounts of food protein in a diet. In practice, it turns out that intake of most essential amino acids in most diets is adequate, provided total protein intake is adequate. The exception to this rule is the dietary essential amino acid lysine, which is discussed in detail later in this chapter.

Bioavailability

Adequate protein supply is one aspect of protein nutrition. A further important aspect is bioavailability: getting the amino acids from the food structures in the gastrointestinal tract to the cells that need them throughout the body. In the adult gastrointestinal tract, proteins must be broken down to very small oligopeptides (at most di- or tripeptides) in order to be taken up, and to single amino acids in order to enter most metabolic pathways. Thus it is necessary for the protein in foods to be both accessible to digestive enzymes and to be broken down by the digestive enzymes in the stomach and small intestine in particular. Furthermore, it is necessary that the broken down protein is able to be taken up into the bloodstream, where it can be redistributed to the tissues that need it. The efficiency of digestion of most of the common food protein sources has been determined, using a range of different methods. Past methodology has largely been based on so-called fecal digestibility. This method is now known to be flawed, particularly with respect to foods with poor digestibility; however it has been widely used and is the only method for which literature values are available for most common foods. For a full discussion of protein quality and nutritional requirements, the reader is referred to a recent FAO report, Protein Quality Evaluation in Human Nutrition (FAO, 2013b).

By using digestibility values, dietary intake can be converted to an estimated uptake into the body for these proteins, noting that these values are derived from a flawed methodology and so, particularly in the case of plant-derived proteins, represent an upper limit of their true bioavailability. The digestibility of a range of dietary proteins is given in Figure 1.3.

Figure 1.3 True protein digestibility of common food proteins. Data from FAO (1970) and WHO/FAO (1991).

Animal-derived proteins generally have good bioavailability and content of dietary essential amino acids, but many plant proteins are deficient in one or more dietary essential amino acids, and many are not efficiently digested and therefore the constituent amino acids are not highly bioavailable. Most Western countries are characterized by a high protein diet with a strong emphasis on animal-derived protein, so protein nutrition is not generally a problem (although there may be some issues with protein nutrition among the elderly). Most developing countries are very dependent on plant protein as the main dietary source, and that protein may be inadequate, due to poor digestibility and poor amino acid balance, particularly in the case of lysine.

World Protein Supply and Its Regional Distribution

Information on the amount of protein available per capita and by protein source in each country is available from the FAOSTAT database (http://faostat.fao.org/). In Figure 1.4, we present the average protein availability for individual countries, along with their total population. These statistics are presented as the total number of people who reside in countries with corresponding average protein availability for each incremental 5 g band. The figure is striking in having two clear peaks, one in the range 55–60 g protein per capita per day, and the second in the band 85–90 g protein per capita per day, with a considerable tail to the right. The first of these peaks is of some concern: It represents more than a quarter of the world's population, and it is simple to calculate that with a standard body weight of 70 kg; based on the dietary recommendations for protein requirements, a person will need 56 g of protein a day to stay healthy. The band at 55–60 includes India, Indonesia, Bangladesh, and the Democratic People’s Republic of Korea (North Korea). This band is of concern because, although the average availability figure is just above the minimum requirement, disparities of income and situation in these countries will mean that a large proportion of these people are not getting enough protein. Furthermore, these figures are just for total protein supply, with no correction for bioavailability. When the dietary pattern is corrected for digestibility of the main protein components of the diet (from FAOSTAT), the situation is more serious, with almost 1.8 billion people getting, on average, less than 55 g of protein per day based on FAOSTAT figures for 2009.

Figure 1.4 Protein intake by population on a country average basis. Each bar represents the total population of countries with average per capita daily protein intake in bands of 5 g/capita/day. Protein figures for 2007 from FAOSTAT September 2012; population data from United Nations (2009).

Vegetable and Animal Protein Sources with a Focus on Dairy Foods

There is considerable debate over the merits of vegetarianism and over eating only vegetable-origin foods in consideration of global sustainability. It is often estimated that production of 1 kg of animal-origin food requires 10 kg of plant-origin food, leading to the simplistic assumption that 10 times as many people could be fed off the same resources if everyone was vegetarian. For a full discussion of the subject, the reader is referred to Fairlie (2010). In the case of dairy products and eggs, the situation is somewhat better than it is for meat, because the animal can continue producing throughout its adult lifetime. This leads to conversion ratios of about 4:1. In fact, the argument is much more complex, partly because of the role of animals in subsistence agriculture, largely eating food waste or processing residue, or grazing and browsing plant species that are not suitable for human consumption, and partly because of the niche many animals occupy in developed agricultural economies, either grazing pastures intensively, or being farmed on land not suitable for arable cultivation (e.g., see Elferink et al., 2008). In this context, we have calculated that in the Canterbury Plains in New Zealand, the main wheat-growing area, the yield per hectare per annum of protein from the wheat crop, processed to the form of white flour and its consequent baked products, is somewhat less than the yield of protein from milk that is produced over the same period in the same area. Thus, the efficiencies of production need to be considered in the context of what is the target of that production (there is no doubt that wheat produces the greater number of calories). Nevertheless, it must be recognized that the changing protein consumption patterns, involving more animal-based products, have significant implications for global land-use patterns, agriculture, agri-food industries, cereal prices, and the environment.

Growing Global Demand for Animal Proteins and Implications

The demand for animal protein foods is expected to increase to about double the present consumption by 2050, driven by population growth and by the emerging middle classes in developing countries (FAO, 2006). As people get more money, one of the first priorities is better food, and this usually means animal protein foods. This phenomenon was first described by Bennett (1941), who related comparative studies of the consumption of staple foods leading to what has come to be known as Bennett's Law: the empirical generalization that there is an inverse relationship between the percentage of total calories derived from cereals and other staple foods and per capita income. This principle has since become generalized to mean a move away from carbohydrate-based foods to protein-based foods.

A simple extrapolation from past increases in animal production indicates that we should be able to meet this demand if past rates of increase can be sustained (Boland et al., 2013). However, past increases have been based on bringing in new land for farm production, increases in efficiency through breeding gains, better livestock management and nutrition, and other factors revolving around the Green Revolution. Most of these options are either reaching their limits or entering a phase of diminishing returns. The carbon footprint of livestock production is a further constraint, although the good news is that as animal production has intensified, the carbon footprint has massively decreased. For example, Capper et al. (2009) have calculated that the carbon footprint for milk in the United States in 2007 was just 37% of that for the same milk in 1944. Nonetheless, past increases will not continue ad infinitum, and new ways of sustainably meeting the increasing demand are needed.

The dietary essential amino acids in proteins

Although there are nine dietary essential amino acids, it is rare for a diet with adequate overall protein intake to be deficient in most of them. The exception is lysine.

Lysine may be an issue for two reasons: The first is that many staple protein sources, particularly the cereals, are deficient in lysine. The second is that lysine is chemically unstable under heating and undergoes a range of reactions when food is heated. The most important of these reactions is the Maillard reaction, in which the side chains of the lysine residues in the protein cross-react with sugar molecules to produce glycosyl lysine side chains that are indigestible and thus no longer bioavailable. This reaction can occur under mild heating conditions, and under more extreme conditions it is responsible for much of the browning of food that occurs during cooking. Another reaction of importance for dairy products is the reaction with phosphoserine, leading to the formation of lysinoalanine, which is not bioavailable. This problem is specific to casein-containing products (mainly milk powders and caseinate), because of its high phosphoserine content (see Chapter 11 for a detailed discussion of this reaction).

Identifying the countries deficient in dietary essential amino acids

In an attempt to obtain an understanding of the dietary availability of the essential amino acids, countries with low intakes of protein were analyzed to determine the dietary essential amino acid content of the mix of protein sources for that country (from FAOSTAT), corrected for digestibility for each protein source. Because literature values were unavailable for some minor protein sources, a sensitivity test was performed, changing the digestibility figure from 1.0 to 0.8 for plant proteins and 1.0 to 0.9 for animal proteins in these cases. Because this change did not make a noticeable difference to overall lysine bioavailability for the countries in question, the method was considered to be robust. The countries found to be lysine deficient are given in Table 1.2, together with information about the main dietary protein sources. Of these countries, only Liberia was found to be deficient for any of the other essential amino acids (leucine and isoleucine in this case).

Table 1.2

Lysine-Deficient Countries

* Other cereals include sorghum, barley, oats, and rye.

The countries that are lysine deficient show a clear pattern of low levels of consumption of animal protein and strong dependence on cereals for their protein.

Protein and Dietary Essential Amino Acid Contents of Food Items

The amino acid composition, particularly the lysine content, of proteins is of particular concern for countries that tend to be protein deficient. Thus maintenance of an adequate intake of lysine, especially in populations with a high dependence on cereals, requires attention. Figure 1.5 indicates the levels of bioavailable lysine in a range of common dietary protein sources. Meat is clearly the best source of lysine but may not be a suitable dietary component for many because of cost and cultural restrictions. Dairy protein is also an excellent source of lysine. Inclusion of supplementary dairy protein in the diet may offer an effective solution that is acceptable to vegetarians, price notwithstanding.

Figure 1.5 Bioavailable lysine content in a range of food protein in g/100 g protein, corrected for digestibility.

Demographic changes, aging populations, and the need for quality protein and essential amino acids

Recent global demographic trends indicate a steady increase in the number of people aged 60 years and over. The projection is for this population to more than triple from 600 million in 2000 to over 2 billion in 2050 (United Nations, 2009). As a consequence, in the more developed world, the fastest growing section of the population is that of adults aged 80 years or over. This clearly presents unique challenges for health care, diets, and nutrition, as well as for certain age-specific clinical conditions.

Both the number and the proportion of older persons are growing in virtually all countries, and these trends are likely to continue worldwide. For example, in 2009, Japan had the highest percentage of the population aged 60 or over, at 29.7%, followed by Italy at 26.4%, whereas in Qatar it was only 1.9%. It is expected that the proportion of the population aged 60 or over will be 22% in 2050 compared to 11% in 2009. Figure 1.6 shows the predicted percentage of the elderly population in 2050 in major continents. By 2050, it is projected that there will be more than 1.4 billion elderly people in Asia alone.

Figure 1.6 Percentage of elderly population in 2050. Sarkar (2012) .

Aging is a continuous, ongoing, and progressive process of damage accumulation. It is associated with reduction in muscle mass and function, and reduced physical activity. The loss of muscle mass with aging is known as sarcopenia. With the aging of the population globally, the prevalence of sarcopenia is likely to increase. Sarcopenia is accelerated by inadequate diet, mainly due to lack of quality protein in optimal quantity and lack of essential amino acids. The issue of the nutritional needs of the growing aging population in terms of the role of dietary protein and essential amino acids with particular reference to sarcopenia is described in more detail in the following sections.

Overall, a strong case can be made that an aging population will require a substantially increased intake of protein and of essential amino acids (particularly leucine), a demand that milk proteins are particularly well suited to meet.

Protein Nutritional Needs of the Elderly

The aging process is characterized by changes in body composition, with a progressive loss of muscle and bone mass, strength, and metabolic function. The loss of muscle with aging is the result of a chronic imbalance between muscle protein synthesis and breakdown. There are many causes of sarcopenia, and an understanding of the complex mechanism is evolving. This degenerative loss of skeletal muscle occurs at a rate of 3 to 8% per decade after the age of 30 and accelerates with advancing age; chronic muscle loss is estimated to affect 30% of people older than 60 years and 50% of those older than 80 years (Katsanos et al., 2006; Paddon-Jones et al. 2008). With the aging of the population, the prevalence of sarcopenia and the resulting burden of disability are likely to increase. Strategies to prevent sarcopenia are, therefore, of considerable importance, and there is a need for public awareness, as simple health strategies can be effective.

Researchers have identified two measures that can play a role in fighting against sarcopenia: diet and exercise. However, in the case of many elderly individuals, the ability to perform exercise is compromised due to disease and disability. In this case, daily high-quality protein intake can be helpful to slow down or prevent muscle protein loss. Different protein sources have been found to stimulate muscle protein synthesis in varying degrees. The most important factor is the amount of essential amino acids in the protein, in particular, leucine. Differences in digestibility and bioavailability of certain protein-rich foods may also influence muscle protein synthesis (Paddon-Jones et al., 2008).

Currently, there is no agreement on whether dietary protein needs change with advancing age. For adults the recommended dietary allowance for protein is 0.8 g protein per kg body weight per day (WHO, 2007). The report of the FAO/WHO/UNU expert consultation, published in 2007, recommends that the essential amino acid requirement for elderly people should be the same as for adults, as the current acceptable methodologies are not appropriate to make a separate set of essential amino acid values for elderly people (WHO, 2007). A more recent FAO-sponsored expert consultation has failed to resolve this issue, with one group maintaining that the data based on the currently acceptable methodologies... are inadequate to make a separate recommendation for dietary IAA requirements in elderly people (Pillai & Kurpad, 2012), while another group has advised that:

dietary protein intake, and the resulting increased availability of plasma amino acids, stimulates muscle protein synthesis. If all other variables are controlled, increased muscle protein synthesis leads to improved muscle mass, strength, and function over time. Increased muscle mass, strength, and function are related to improved health outcomes in older individuals. Since adverse effects of reasonable increases in protein intake above the recommended dietary allowance (RDA) of 0.8 g protein/kg/day have not been reported, it is reasonable to conclude that the optimal protein intake for an older individual is greater than the RDA (Wolfe, 2012).

Some studies suggest that an intake of 1.0–1.5 g protein per kg body weight per day or about 15–20% of total caloric intake is essential to preserve proper nitrogen balance in the healthy elderly instead of the recommended RDA value (Morais et al., 2006; Wolfe et al., 2008).

Role of Essential Amino Acids in Nutrition of the Elderly

Essential amino acids are mainly responsible for the stimulation of muscle protein anabolism in the aged (Volpi et al., 2003). It is considered that 15 g of essential amino acids taken as bolus is required for maximum stimulation of muscle protein synthesis (Wolfe, 2002). This indicates that quality of protein is very important in the diet of the elderly.

Preliminary data from a recent randomized controlled trial indicate that it is more important to ingest a sufficient amount of high-quality protein (25–30 g) with each meal rather than one large bolus, because more than 30 g in a single meal may not further stimulate muscle protein synthesis (Symons et al., 2009). It is also recognized in recent studies that intake of whey protein brings beneficial effects to muscle protein anabolism in the elderly. Furthermore, ingestion of intact whey protein has been found to provide a greater anabolic benefit than ingestion of the equivalent essential amino acids alone. Thus, whey protein may be more than just a simple source of essential amino acids with respect to providing a stimulus for enhancing muscle protein anabolism in the elderly (Katsanos et al., 2008). For a fuller discussion of the function of whey proteins and other milk proteins in human health, the reader is referred to Chapter 19 of this volume.

There is a general agreement that the essential amino acid leucine increases protein anabolism and decreases protein breakdown (Paddon-Jones and Rasmussen, 2009). Leucine-rich food sources include legumes such as soybeans and cowpea, and animal products such as beef, fish, and particularly dairy proteins (whey protein). It is reported that amino acid supplements without adequate leucine do not stimulate protein synthesis (Rieu et al., 2007; Hayes and Cribb 2008). Leucine has recently been acknowledged to be especially important as a signaling molecule and a building block for muscle. Rat studies show that leucine can directly stimulate muscle protein synthesis through increasing mRNA translation (Anthony et al., 2000). Insulin and leucine are anabolic stimuli for muscle, and both share a common pathway of action via activation of a kinase known as mTOR. mTOR is the main regulator of cell growth and acts by phosphorylating target proteins involved in mRNA translation. Because insulin sensitivity decreases with age, one possible mechanism by which amino acids (mainly leucine) might improve muscle mass is by providing another anabolic stimulus to activate the mTOR-controlled pathway (Gaffney-Stomberg et al., 2009; Casperson et al. 2012).

No differences exist in protein balance in the elderly relative to the young following administration of either 30 g of beef protein or 15 g of essential amino acids as a bolus (Paddon-Jones et al., 2004). However, when 6.7 g of a mix of the dietary essential amino acids is given, the overall protein synthetic response is reduced in the elderly relative to the young (Katsanos et al., 2005). This anabolic resistance has been attributed to a decrease in leucine sensitivity and may be overcome by increasing the proportion of this amino acid in the diet. For example, when a 6.7 g bolus of dietary essential amino acids enriched with leucine (46% leucine compared to the 26% normally found in whey protein) was given to the elderly individual, protein synthesis was fully restored (Katsanos et al., 2006).

Global trade in proteins, the long-term prospects, with a focus on dairy foods

Global food consumption patterns have been changing in recent decades in several significant ways. Among them is the noticeable and continuing shift in favor of proteins, especially animal proteins. Global consumption of protein is forecast to grow by 96% over the three decades from 1990 to 2020 (von der Heyde, 2012). The growth is largely due to the rising incomes in the developing world, particularly in some of the more populous countries such as China, Brazil, and, to a lesser extent, India. Over the decade since 2000, however, global protein demand has been driven by increased consumption in other countries and geographic areas too. For example, demand in the African continent has increased by around 70%, in Southeast Asia by 49% and in Central America by 29% (von der Heyde, 2012). Between 1999 and 2011, world protein trade grew by 74% (von der Heyde, 2012). Since only a few countries currently have surplus protein to export, the projected increase in its demand is likely to pose serious challenges to these countries and to the world in general.

In overall world protein nutrition, milk products, representing about 10% of all protein consumption, are the third most important source of protein after cereals (40%) and meat (18%) (data for 2009 from FAOSTAT). When the low levels of lysine in cereals are taken into account (about one-third of that in dairy products), it is clear that milk protein plays a very important nutritional role in the world today.

The Global Dairy Food Scene: An Overview

Milk and other dairy products have always been among the major everyday food items in human consumption in many cultures. It is a particularly useful food for the large, and possibly growing, number of vegetarians around the world. Its value for both infants and the elderly is easily recognized. Apart from its consumption in liquid form, there are many other ways in which milk is transformed and consumed. Innovations keep occurring to make new milk-based products available in the market.

With growing world population and changing food habits, the production and consumption of milk and other milk-based products have also been rising over time. Over the five decades since 1961, world milk production more than doubled from 344 million tons to 703 million tons in 2009 (FAOSTAT) and 749 million tons in 2011 (IDF, 2012).

The pattern of regional distribution of the production and consumption of milk reveals that, as of 2009, Asia's share is the highest—with 36% of global production and 38% of consumption; Europe comes next, with 31% and 30%, respectively, followed by North America with a balanced 13% of both production and consumption, and South America, again with a balanced 8% of production and consumption. The only region with a significant exportable surplus is Oceania, which produces 3.7% and consumes 1.5% of the global totals.

It is important to note that much of the milk produced is consumed in the country (or economic bloc, in the case of the EU) where it is produced, and that just over 8% of dairy production is involved in international trade (2011 figures; IDF, 2012). In this context, it is noted that about 80% of whole milk powder, 55% of skim milk powder, and only about 10% of cheese is traded internationally (IDF, 2012). It is of interest to note, too, that trade in cheese within the EU-27, for example, was five times the volume exported, which in turn was only 8% of production. In 2012, the major exporters of cheese were the EU-27, the United States, New Zealand, and Australia, and the main importers were Russia, Japan, the EU-27, Mexico, and Korea (USDA, 2012). There is, evidently, some intraindustry trade in cheese. Given its variety and established regional specialties, this is not difficult to understand.

The six major exporters account for 80% of world dairy trade in cow’s milk (IDF, 2012). They were, in 2011, New Zealand (26%), the EU-27 (26%), the United States (12%), Australia (8%), Argentina, and Belarus (4% each). Of course, all of the exported ‘milk’ consists of processed products, of which the main ones that contain protein (in order of importance) are whole milk powder, skim milk powder and cheese. Different countries dominate the export markets of the different dairy products (Table 1.3).

Table 1.3

Volume of Major Dairy Exports for the Six Main Exporters, 2011

a Excludes other products such as casein, whey products, and liquid and condensed milks. Values are based on protein of: WMP 25%; SMP 35%; and cheese 25%. The cheese value is based on the bulk of traded cheese being cheddar. Values were obtained from the Canadian Dairy Commission dairy ingredient profiles on www.milkingredients.ca and values near the lower end of each range used.

Source: IDF, 2012.

One notable feature of our discussion is perhaps the absence of the poorer developing countries among the major exporters and importers of such processed high-value milk products as butter and cheese. The possible explanation for this may be that the consumption of these products is income-sensitive; they are consumed in noticeable quantities only when income has reached a certain level.

This presumption is further confirmed when one examines the trade patterns in respect of milk powders, which are usually reconstituted for consumption as liquid milk—the demand for which is likely to be less income-sensitive. Among the major importers of whole milk powder are China, Algeria, Brazil, Indonesia, and the Philippines, while the major exporters are New Zealand, Australia, and the EU-27. The situation is very similar in the market for skim milk powder. The major importing countries are Mexico, China, Indonesia, and the Philippines, and the major exporters are New Zealand, Australia, the United States, and the EU-27.

While China features as a milk importer, India, perhaps surprisingly, is neither a major importer nor a major exporter of dairy products, although it has the largest bovine herd in the world. With the introduction around the mid-1960s of a system of dairy cooperatives under the umbrella of the National Dairy Development Board (NDDB), India's dairy industry has achieved a remarkable transition. Set up in