Caballero B. (ed.) Encyclopaedia of Food Science, Food Technology and Nutrition. Ten-Volume Set

Подождите немного. Документ загружается.

EDITOR-IN-CHIEF

Benjamin Caballero

Johns Hopkins University

Center for Human Nutrition

School of Hygiene and Public Health

615 North Wolfe Street

Baltimore, Maryland 21205-2179

USA

EDITORIAL ADVISORY BOARD

EDITORS

Luiz C Trugo

Laboratory of Food and Nutrition Biochemistry

Department of Biochemistry, Institute of Chemistry

Federal University of Rio de Janeiro

CT Bloco A Lab 528-A

Ilha do Fundao, 21949-900 Rio de Janeiro

Brazil

Paul M Finglas

Institute of Food Research

Norwich Laboratory

Colney Lane

Norwich, NR4 7UA

Peter Belton

AFRC Institute of Food Research

Norwich Laboratory

Colney Lane

Norwich NR4 7UA

Peter Berry Ottaway

Berry Ottaway Associates Ltd

1A Fields Yard

Plough Lane

Hereford HR4 0EL

Ricardo Bressani

Universidad del Valle de Guatemala

Institute de Investigaciones

Aparto 82

Guatemala 01901

Barbara Burlingame

Food and Agriculture Organization of the United Nations

Viale delle Terme di Caracalla

Rome 00100

Italy

Jerry Cash

Michigan State University

Department of Food Science and Human Nutrition

East Lansing

MI 48824

USA

Colin Dennis

Campden & Chorleywood Rood Research Association

Chipping Campden

Gloucestershire GL55 6LD

Johanna T Dwyer

Tufts University

USDA Human Nutrition Research Center

711 Washington Street

USA

Tee E-Siong

Institute of Medical Research

Division of Human Nutrition

Jalan Pahang

Kuala Lumpur 50588

Malaysia

Patrick F Fox

University College

Department of Food Chemistry

Cork

Republic of Ireland

Jesse Gregory

University of Florida

Food Science and Human Nutrition Department

PO Box 110370

Newell Drive

Gainesville

FL 32611-0370

USA

RJ Hamilton

10 Norris Way

Formby

Merseyside L37 8DB

George D Hill

Lincoln University

Plant Sciences Group

Field Service Centre

Soil, Plant and Ecological Sciences Division

PO Box 84

Canterbury

New Zealand

Harvey E Indyk

Anchor Products Limited

PO Box 7

Waitoa

New Zealand

Anura Kurpad

St John’s Medical School

Department of Nutrition

Bangalore

India

Jim F Lawrence

Sir FG Banting Research Centre, Tunney’s Pasture

Health and Welfare Canada, Health Protection Branch

Ottawa

Ontario K1A 0L2

Canada

F Xavier Malcata

Universidade Catolica Portugesa

Escola Superior de Biotecnologia

Rua Dr Antonio Bernardino de Almeida

Porto 4200

Portugal

Keshavan Niranjan

University of Reading

Department of Food Science and Technology

Whiteknights

PO Box 226

Reading

Berkshire RG6 2AP

John R Piggott

University of Strathclyde

Department of Bioscience and Biotechnology

204 George Street

Glasgow

Scotland G1 1XW

Vieno Piironen

University of Helsinki

Department of Applied Chemistry & Microbiology

PO Box 27

Helsinki FIN-00014

Finland

vi EDITORIAL ADVISORY BOARD

Jan Pokorny

Prague Institute of Chemical Technology

Department of Food Science

Technicka Street 5

CZ-16628 Prague 6

Czech Republic

Terry A Roberts

59 Edenham Crescent

Reading

Berkshire RG2 6HU

lia B Rodriguez-Amaya

University of Campinas

Department of Food Science

Faculty of Food Engineering

PO Box 6121

Campinas

SP 13081-970

Brazil

Jacques P Roozen

Wageningen University

Agrotechnology and Food Sciences

Laboratory of Food Chemistry

PO Box 8129

6700 EV Wageningen

The Netherlands

Steve L Taylor

University of Nebraska Lincoln

Department of Food Science and Technology

143 H C Filley Hall

East Campus

Lincoln

NE 68583-0919

USA

Jean Woo

Chinese University of Hong Kong

Department of Medicine

Prince of Wales Hospital

Shatin

N.T

Hong Kong

David C Woollard

AgriQuality NZ Ltd

Lynfield Food Services Centre

131 Boundary Road

PO Box 41

Auckland 1

New Zealand

Steven Zeisel

University of North Carolina at Chapel Hill

Department of Nutrition

2212 McGavran-Greenberg Hall

Chapel Hill

NC 27599-7400

USA

EDITORIAL ADVISORY BOARD vii

FOREWORD

There are no disciplines so all-encompassing in human endeavours as food science and nutrition. Whether it be

biological, chemical, clinical, environmental, agricultural, physical – every science has a role and an impact.

However, the disciplines of food science and nutrition do not begin or end with science. Politics and ethics,

business and trade, humanitarian efforts, law and order, and basic human rights and morality all have

something to do with it too.

As disciplines, food science and nutrition answer questions and solve problems. The questions and problems

are diverse, and cover the full spectrum of every issue. Life span is one such issue, covered from the nutritional

basis for fetal and infant development, to optimal nutrition for the elderly. Another such issue is the time span

of the ancient and wild agro-biodiversity that we are working to preserve, to the designer cultivars from

biotechnology that we are trying to develop. Still another is the age-old food preparation methods now

honoured by the ‘eco-gastronomes’ of the world, to the high tech food product development advances of

recent years.

As with most endeavours, our scientific and technological solutions can and do create new, unforeseen

problems. The technologies that gave us an affordable and abundant food supply led to obesity and chronic

diseases. The ‘‘green revolution’’ led to loss of some important agro-biodiversity. The technological innovation

that gave us stable fats through hydrogenation, flooded the food supply with trans fatty acids. All these

problems were identified through a multidisciplinary scientific approach and solutions are known. When

technology created the problem and technology has found the solution, implementation is usually more

successful. Reducing trans fatty acids in the food supply is case in point. Beyond the technologies, the solutions

are more difficult to implement. We know how obesity can be reduced, but the solution is not directly

technological. Hence, we show no success in the endeavour.

Of all the problems still confounding us in food science and nutrition, none is so compelling as reducing the

number of hungry people in the world. FAO estimates that there are 800 million people who do not have

enough to eat. The World Food Summit Plan of Action, the Millennium Development Goals and other

international efforts look to food science and nutrition to provide the solution. Yet we only have part of the

solution—the science part. The wider world of effort in food science and nutrition needs to be more

conscientiously addressed by scientists. This is the world of advocacy and action: advocacy for food and

nutrition as basic human rights, coupled with action to get food where it is needed.

But all those efforts would be futile if they are not based on sound scientific information. That is why works

such as this Encyclopedia are so important. They provide to a wide readership, scientists and non-scientists

alike, the opportunity to quickly gain understanding on specific topics, to clarify questions, and to orient to

further reading. It is a pleasure to be involved in such an endeavour, where experts are willing to impart their

knowledge and insights on scientific consensus and on exploration of current controversies. All the while, this

gives us optimism for a brighter food and nutrition future.

Barbara Burlingame

25 February 2003

INTRODUCTION

There is no factor more vital to human survival than food. The only source of metabolic energy that humans

can process is from nutrients and bioactive compounds with putative health benefits, and these come from the

food that we eat. While infectious diseases and natural toxins may or may not affect people, everyone is

inevitably affected by the type of food they consume.

In evolutionary terms, humans have increased the complexity of their food chain to an astounding level in a

relatively short time. From the few staples of some thousand years ago, we have moved to an extraordinarily

rich food chain, with many food items that would have been unrecognizable just some hundred years ago.

In this evolution, scientific discovery and technical developments have always gone hand in hand. The

identification of vitamins and other essential nutrients last century, and the development of appropriate

technologies, led to food fortification, and thus for the first time humans were able to modify foods to better

fulfill their specific needs. As a result, nutritional deficiencies have been reduced dramatically or even

eradicated in many parts of the world. This evolution is also yielding some undesirable consequences. The

abundance of high-density, cheap calorie sources, and the market competition has facilitated overconsumption

and promoted obesity, a problem of global proportions.

As the food chain grows in complexity, so does the scientific information related to it. Thus, providing

accurate and integral scientific information on all aspects of the food chain, from agriculture and plant

physiology to dietetics, clinical nutrition, epidemiology, and policy is obviously a major challenge.

The editors of the first edition of this encyclopedia took that challenge with, we believe, a great deal of

success. This second edition builds on that success while updating and expanding in several areas. A large

number of entries have been revised, and new entries added, amounting to two additional volumes. These new

entries include new developments and technologies in food science, emerging issues in nutrition, and addi-

tional coverage of key areas. As always, we have made efforts to present the information in a concise and easy

to read format, while maintaining rigorous scientific quality.

We trust that a wide range of scientists and health professionals will find this work useful. From food

scientists in search of a methodological detail, to policymakers seeking update on a nutrition issue, we hope

that you will find useful material for your work in this book. We also hope that, in however small way, the

Encyclopedia will be a valuable resource for our shared efforts to improve food quality, availability, access,

and ultimately, the health of populations around the world.

Benjamin Caballero

Luiz Trugo

Paul Finglas

Acceptability of Food See Food Acceptability: Affective Methods; Market Research Methods

ACESULFAME/ACESULPHAME

J F Lawrence, Health and Welfare Canada, Ontario,

Canada

Background

0001 Acesulfame K (potassium salt of 6-methyl-1,2,3-

oxathiazine-4(3H)-one-2,2-dioxide; Figure 1)isa

high-intensity artificial sweetener which is about

200 times as sweet as sucrose (compared to a 3%

aqueous sucrose solution). It was accidentally dis-

covered in 1967 by Dr. Karl Clauss, a researcher

with Hoechst AG in Frankfurt, FRG, during his ex-

periments on new materials research. The sweetener

is not metabolized by the human body and thus con-

tributes no energy to the diet. It is now approved for

use in more than 20 countries.

Sweetness

0002 The sweetness properties of acesulfame K are similar

to saccharin. It has a clean, sharp, sweet taste with a

rapid onset of sweetness and no lingering aftertaste at

normal use levels. However, at high concentrations,

equivalent to 5% or 6% sucrose solutions, acesul-

fame K does possess a bitter, chemical aftertaste.

The intensity of sweetness of acesulfame K, in

common with other artificial sweeteners, varies

depending upon its concentration and the type of

food application. For example, it is 90 times sweeter

than a 6% sucrose solution, 160 times sweeter than a

4% sucrose solution and 250 times sweeter than a 2%

sucrose solution. Mixtures of acesulfame K with

other intense sweeteners, such as aspartame or cycla-

mate, result in some synergistic increases in sweet-

ness. Mixtures with saccharin are somewhat less

synergistic.

Production and Physical and Chemical

Properties

0003Acesulfame K (Figure 1) is structurally related to

saccharin. It also has many of the same physical and

chemical properties.

0004Acesulfame was one of a series of sweet-tasting

substances synthesized by Hoechst AG in the late

1960s. All of these had in common the oxathiazinone

dioxide ring structure. The synthesis involved reac-

tion of fluorosulfonyl isocyanate with either acetylene

derivatives or with active methylene compounds such

as a-diketones, a-keto acids, or esters. The latter re-

action is used for the commercial production of ace-

sulfame K. A generalized reaction scheme for

synthesis of the oxathiazinone dioxide ring structure

is shown in Figure 2. Many analoges have been pre-

pared and evaluated for taste properties. The potas-

sium salt of the 6-methyl derivative, acesulfame K,

displayed the best sensory and physical properties and

thus it has received extensive testing aimed at

obtaining approval for its use in diet foods.

0005Acesulfame K is a white crystalline material which

is stable up to 250



C, at which temperature it decom-

poses. The free acid form of the sweetener has a

distinct melting point of 123.5



0006Acesulfame K has a specific density of 1.83. When

dissolved in water it produces a nearly neutral solu-

tion while the free acid is strongly acidic (pH of a 0.1

mol l

1

aqueous solution being 1.15). The sweetener

is very soluble in water; a 27% solution can be

prepared at 20



C. The solubility of acesulfame K

increases significantly with temperature. At 80



50% solutions can be prepared; because of this,

greater than 99% purity can be obtained by

crystallization. It is substantially less soluble in

common solvents such as ethanol, methanol, or

acetone.

0007 The stability of acesulfame K in the solid state is

very good. It can be stored at ambient temperature for

10 years without decomposition. Aqueous solutions

at pH 3 or greater may also be stored for extended

periods without detectable decomposition or loss of

sweetness. However, below pH 3, significant hydroly-

sis may occur at elevated temperatures. For example,

at pH 2.5 an aqueous buffered solution of acesulfame

K would decompose by about 30% after 4 months of

storage at 40



C, whereas no decomposition occurs

under the same conditions within the pH range of

3–8. At 20



C, less than 10% decomposition of ace-

sulfame K occurs after 4 months’ storage at pH 2.5,

indicating that under normal storage conditions

aqueous solutions of the sweetener are very stable.

0008 Acesulfame K is stable under most food-processing

conditions, including the elevated temperature treat-

ments encountered in pasteurization and baking.

Food Uses

0009 Because of its stability, acesulfame K has been evalu-

ated in a wide variety of diet food products, including

table-top sweeteners, soft drinks, fruit preparations,

desserts, breakfast cereals, and chewing gum. Table 1

lists approximate concentration levels of acesulfame

K typically used in several types of foods.

Safety and Regulatory Status

0010Acesulfame K has been subjected to extensive feeding

studies in mice, rats, and dogs. The substance is not

considered to be carcinogenic, mutagenic, or terato-

genic. It is excreted unmetabolized in test animals

or humans. The current maximum acceptable daily

intake (ADI: the maximum amount that can be con-

sumed daily for a lifetime without appreciable risk)

established by the Food and Agriculture Organiza-

tion/World Health Organization (FAO/WHO) Joint

Expert Committee on Food Additives in 1990 is 5 mg

per kg body weight. This value is based on the highest

amount fed to animals for which there was no effect.

0011The first regulatory approval for acesulfame K was

by the UK in 1983. Since then it has received approval

for specific uses in more than 20 countries.

Analysis

0012Thin-layer chromatography, isotachorphoresis, and

high-performance liquid chromatography (HPLC)

have been evaluated for the determination of ace-

sulfame K in a variety of matrices, including liquid

and solid food products, animal feed, and biological

fluids. Of the three, HPLC is perhaps the most useful

since the efficiency of the chromatography coupled

with selective detection (ultraviolet absorbance)

enable quantitative measurements to be made in

rather complex food samples. In addition, the sample

preparation is minimal, usually involving a water

extraction for solid samples or a filtration and dilu-

tion of liquid samples before direct HPLC analysis.

Acesulfame K has been incorporated into a multi-

sweetener analytical method employing HPLC.

See also: Carbohydrates: Sensory Properties;

Chromatography: High-performance Liquid

Chromatography; Gas Chromatography; Legislation:

Contaminants and Adulterants; Saccharin; Sweeteners:

Intensive

tbl0001Table 1 Typical use levels of acesulfame K in diet foods

Food products Concentration (mg kg

1

)

Soft drinks 1000

Coffee and tea 267

Jams and marmalades 3000

Ready-to-eat desserts 1000

Chewing gum 2000

−

fig0001 Figure 1 Structure of acesulfame K. Reproduced from Acesul-

phame/Acesulfame, Encyclopaedia of Food Science, Food Tech-

nology and Nutrition, Macrae R, Robinson RK and Sadler MJ

(eds), 1993, Academic Press.

NSO

NaOH

∆

Fluoro-

sulfonyl-

isocyanate

fig0002 Figure 2 Synthesis of the acesulfame ring structure using

fluorosulfonyl isocyanate and tert-butylacetoacetate as start-

ing materials. Reproduced from Acesulphame/Acesulfame, En-

cyclopaedia of Food Science, Food Technology and Nutrition,

Macrae R, Robinson RK and Sadler MJ (eds), 1993, Academic

Press.

2 ACESULFAME/ACESULPHAME