Table Of ContentFOOD SCIENCE AND TECHNOLOGY
A SERIES OF MONOGRAPHS
Editor Emeritus
Bernard S. Schweigert
University of California, Davis
Series Editor
Steve L. Taylor
University of Nebraska, Lincoln
Food Science and Nutrition Editorial Advisory Board
Douglas Archer John E. Kinsella
Center for Food & Applied Nutrition Cornell University, Ithaca
FDA, Washington
Daryl B. Lund
Jesse F. Gregory, III State University of New Jersey,
University of Florida, Gainsville New Brunswick
Susan K. Harlander Barbara 0. Schneeman
University of Minnesota, St Paul University of California, Davis
A complete list of the books in this series is available from the publishers on request
The Chemistry and Technology
of Edible Oils and Fats
and their High Fat Products
G. Hoffmann
Meeuwenlaan 26
3055 CM Rotterdam
The Netherlands
ACADEMIC PRESS
Harcourt Brace Jovanovich, Publishers
London San Diego New York Berkeley
Boston Sydney Tokyo Toronto
ACADEMIC PRESS LIMITED
24-28 Oval Road
LONDON NW1 7DX
United States Edition published by
ACADEMIC PRESS INC.
San Diego, CA 92101
Copyright © 1989, by
ACADEMIC PRESS LIMITED
All Rights Reserved
No part of this book may be reproduced in any form by photostat,
microfilm, or any other means, without written permission
from the publishers
British Library Cataloguing in Publication Data
Hoffmann, G.
The chemistry and technology of edible oils
and fats and their high fat products
1. Fats & Oils
I. Title
664\3
ISBN 0-12-352055-X
Typeset by Bath Typesetting Ltd, Bath
Printed in Great Britain by St Edmundsbury Press Ltd, Bury St Edmunds, Suffolk
Foreword
The chemistry and technology of edible oils and fats, as well as the products
which contain these ingredients, constitutes an area in which many books
deal both with the general and specific aspects of this subject. Consequently
it requires courage and creativity to be able to add to the existing range of
publications in the field. Géza Hoffmann, who can draw on more than thirty
years of experience involving the many facets of the chemistry and tech
nology of edible oils and fats during his work as a research chemist in
Unilever Research, has filled the gap in the range of publications. He has
produced a concise review which enables the reader to familiarize himself
quickly and thoroughly with the subject while at the same time providing up-
to-date information to the processors of edible oils and fats in a readily
accessible form. I feel confident that this work will meet a long-felt need.
C. Okkerse,
R & D-Director Edible Fats,
Unilever Research Laboratorium Viaardingen,
Vlaardingen, The Netherlands
v
Introduction
The use of animal and vegetable fats and oils for edible purposes has as long
a history as mankind itself. Their use in cooking in the everyday life of
ancient cultures, like the Chinese, Egyptian and Greco-Roman, was just as
important as it is in ours, notwithstanding their much lower production and
per capita use.
The oldest known fats are those found in pots in the tombs of pharaohs.
Some written reports in 1400 B.C. described the use of, probably, animal fats
when "moving large stones on wooden logs", the biggest engineering
achievement of ancient Egypt. Residues of soap have been found in a soap
boiler, which was used to produce soap from potash and fats, in the ruins of
Pompei. Ancient night lights used animal fat with a sort of cane or reed as
the wick. The Romans knew candles made from tallow, the better sorts
containing a mixture of tallow and beeswax. Regarding the use of oils, olives
of the Mediterranean, rape seed of Europe, sesame seed of India and soya
beans of China are amongst the oldest oil plants described by the ancients.
The sources of fats and oils were then, as they are now, plants and
animals, the latter being primarily land animals, the use of marine animals
being secondary. Mainly under the pressure of an ever growing world
population, new fatty raw material resources have been discovered. Agri
cultural techniques have also been improved by chemical, biochemical and
mechanical technological research and development, all this leading to high
yielding, climate and disease resistant crop varieties. In times of serious
shortage (e.g. wars, crises) both the fatty acids and glycerol, the main
building blocks, could be synthesized if not for edible then at least for
technical purposes. The biological synthesis of fats by means of micro
organisms is completely feasible, although this is not done because of the
relatively low pressure on the part of the fat/oil industry.
As regards the required technology, the Chinese knew the use of wedges,
whereas Plinius the Elder described the use of double-edged running grind
ing stones rotating in a stone pan for crushing olives. The heating of crushed
masses of seeds before pounding the mass, e.g. by stones in sacks, was a well
known part of early technology. The use of animal, wind and water energy
instead of human labour when grinding and stamping or pounding the mass
IX
X INTRODUCTION
were medieval developments. The microbiological way of "rotting" the oil-
bearing seeds was also well known, although only practised for technical
purposes, e.g. for linseeds. However, the real breakthrough came in the
preindustrial age with the application of roller-type grinders, introduced by
Smeaton in 1752. The introduction of hydraulic presses for other purposes
by the discovery of Brahma (1795) and Neubauer (1800) led to the appli
cation of plate presses by Montgolfier (1819). The dehulling and air
aspiration of cotton seed was introduced by Waring (1826), whereas the
power requirements of hydraulic pressing were reduced by the accumulators
developed by Armstrong (1843). The first patents for solvent extraction were
issued to Deiss (1855) and Seyferth (1858), proposing carbon disulphide as
solvent. Irvine, Richardson and Lundy (1864) issued a patent for the use of
hydrocarbon solvents, the basis of the present-day technology. Marticke
(1877) proposed the use of screw presses, although the first true expeller was
introduced by Anderson in 1906. Mege Mouries obtained the first patent on
the production of margarines in 1869, thus providing the fundamental basis
for a breakthrough in feeding in the industrializing Western world with a
cheap butter-like high-calory spread. The invention of catalytic fat-harden
ing by Normann in 1902 gave the industry independence from hard animal
fats, like lard and tallow, which thus made possible the use of cheap marine
oils, such as fish and whale oils. It is a sad fact that this development
has led to a near extinction of certain whale populations, but at least today
the whales killed serve primarily as a protein source and are used mainly in
the petfood and delicatessen industries and not in the edible fat industries.
Among other things the continuous-chain and basket-type extractors
invented by Bollmann in the 1920s gave a huge impetus to the development
of a primarily animal-feed (protein) directed soya-bean industry, using many
different types of extractors in order to produce enormous daily amounts of
defatted meal and the "side product", the oil.
Having thus reviewed briefly the main steps in the technological develop
ment of the industry, it is fair to recall some major points of the scientific
development, which have made it possible to reveal the fine structure of oils
and fats. In 1741, Geoffroy observed that soap acidified by mineral acids is
decomposed to a substance that is soluble in alcohol, this in contrast to the
original raw material, the fats. Scheele, in 1779, when saponifying fats with
lead oxide, produced a water miscible product, which he called "sweet oil".
Today we call this product glycerol. Chevreul, over the years 1813-1825,
identified the acid character of the substances we know as fatty acids,
and established the alcohol character of glycerol and the role of water in
saponifying fats. Because of this work, Chevreul is considered the founder of
modern fat chemistry. Berthelot established the triglycéride (triacylglycerol)
character of fats and hydrolysed and esterified them, respectively, in closed
INTRODUCTION XI
vessels under pressure. The findings of Berthelot over the years 1853—54 were
the basis for the use of fatty acids for many technical purposes. The
introduction of many useful group characteristics, known as "values", are
connected with some personal names, e.g. the "acid-value" with Merz
(1879), the "saponification value" with Koettstorfer (1879), and the first
iodine value with Huebl (1879). The modern elucidation of the triglycéride
composition was begun by Hilditch and his school in the 1930s by means of
fractional crystallization. The introduction of chromatography, executed
originally on columns by Tswett (1906) and developed in the gas phase by
James and Martin (1952), for the separation of fatty acids and derivatives
opened a previously unknown chapter in establishing the chemical compo
sition of fats and oils and other (fatty) substances. Chromatography, in
combination with different methods of instrumental physical analysis and
the application of computers here and on the side of production, processing
and design has completely changed the picture of the edible fat industry in
the last 20 years.
One might wonder why, after the publication of many excellent books on
the chemistry and technology of oils and fats, some of them quite recently,
another book on the same subject was felt necessary for such a relatively
limited field of intellectual and practical interest. Some of these books
cover broadly all the theoretical and practical aspects associated with the
chemistry and technology of oils and fats, and all the fields where they can
be used, not only for edible, but also for technical purposes. Others are
written in languages less mastered by a broad public than English. This book
gives, as an introduction, a concise treatment of fat chemistry. Thereafter the
most relevant fat-separation technologies for the production of the import
ant types of crude fats and oils from seeds, fruits and animal tissues are
described. The oil and fat resources are not enumerated, and the use of
defatted meals as animal feed and oil-seed proteins for human consumption
are not elaborated further. Following this the refining and the most import
ant fat-modification technologies are discussed, as these lead to those edible
oils and fats which are applied in different products of high fat content, e.g.
margarines (except dairy products), shortenings, mayonnaise, etc., and the
speciality fats.
This book is thus written on the one hand for the high-fat food manufac
turer, who is often in control of only the finishing stage and not the raw-
material production and processing stages. If the manufacturer is able to
exert some influence on the selection and production of the raw or partly
processed raw materials (intermediate/half products) used, he might do that
on knowledge secured from books and other publications. On the other
hand, this book might also be of interest to the oil miller or the refiner/
hardener/fat fractionator, who wants some insight into the needs of the
Xll INTRODUCTION
high-fat product manufacturer by taking a look at his specific products and
methods. This aim will be achieved by disclosing many quality aspects of the
half and final products to be controlled, besides some quality criteria of the
important raw/intermediate materials involved in the processing.
The basics of the most important quality-control methods, as standar
dized by the International Union of Pure and Applied Chemistry (IUPAC),
by the American Oil Chemists' Society (AOCS), by the German Society of
Fat Science (Deutsche Gesellschaft fuer Fettwissenschaft, DGF), by some of
those of the International Association of Seed Crushers (IASC) and by the
British Standards Institution (BSI) were highlighted previously by the
present author in Quality Control in the Food Industry (edited by S. M.
Herschdoerfer, Vol. 2, 2nd edn., London: Academic Press, 1986), which can
thus be used as a reference.
This book is dedicated to my wife Edith, whose solidarity,
understanding and patience supported and encouraged me, as
always.
Xlll
Acknowledgements
The author wishes to express his sincere gratitude to all those friends and
colleagues within the Unilever organization and also outside it, who have
reviewed individual chapters in their own area of specialization, including
those who have helped him in the improvement of the draft manuscript as
regards his English. Their advice and comments have been invaluable. The
permission to use the library, internal documentation, some illustration
material and the word-processing facilities of the Unilever Research Labora
tory, Vlaardingen, The Netherlands, the institution in which he served with
pleasure for 33 years, are most gratefully acknowledged. In spite of this long
service contact, all the views given by the author remain solely his own
responsibility and are not necessarily those of Unilever.
Thanks are due to all those publishers, copyright owners, patented process
inventors or equipment manufacturers whose published material has been
used to complete this work. The description or mention of any process or
firm under the illustrations or in the text does not imply any recommen
dation whatsoever of the author, the items serving only as illustrations for
the subjects handled.
When describing the technology and processes it seemed to be of little
value to collate all the items discussed with immediate literature references.
All those publications (books, monographies, journals, etc.) which are
considered to be relevant to the subjects discussed and which can be used as
sources for further information on the matter, are fully cited in the general
and the chapter-wise special literature references at the end of the book. As
an exception, authors whose work contains information more specific to
certain subjects, are individually cited by name and year of publication (in
parentheses) in the text and are fully cited in the special reference list.
xv
