PREFACE 'he symposium upon which this book is based was a continuation - - and updating of a similar one held in 1975 at the First Chemical Congress of the North American Continent in Mexico City, Mexico. The first symposium was entitled " F o o d Proteins: Improvement through Chemical and Enzymatic Modification." The present symposium has a greater emphasis on nutrition and adds pharmacological science. Not only is there a large increase in the amount of information available on these subjects since 1975, but the information is of higher quality and level of sophistication.
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Since the last symposium there have been several changes i n atti tudes or directions. One of these has been the recognition that alkali treatment of proteins is a chemical procedure, and in particular, a chemi cal modification. Another has been the recognition that, although there are still difficult problems in assessing the safety aspects of chemical modifications of foods, both chemical and enzymatic treatments can be useful in laboratory experimentation and, perhaps, i n eventual applica tion to food production. Increase in nutritional value through modifica tions is now recognized. The main purposes of this symposium were to delineate the current status i n protein modification and to describe the major advances. In addition, the speakers and the subjects were selected to show how the different objectives i n food, nutritional, and pharmacological sciences have many common threads, and how chemical and enzymatic modifi cations are used in research in all three fields. These interrelationships are reflected not only i n the practical interest in some of the research results, but also in the actual research laboratories in which some of the industrial organizations have closely intertwined research programs i n more than one of these fields. The laboratory of Thomas Richardson at the University of Wisconsin has used chemical modification of amino groups by reductive methylation with isotopically labeled reagents as an analytical tool to follow the highly important interactions of milk pro teins during handling, processing, and storage. Another use has been the removal of unwanted constituents as shown by the laboratory of John Kinsella at Cornell University where carboxymethylacetylation of amino groups has been used to separate nucleic acids from yeast proteins. ix Feeney and Whitaker; Modification of Proteins Advances in Chemistry; American Chemical Society: Washington, DC, 1982.
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Other uses have been to protect against modifications (the Maillard reaction) during processing. Increases i n nutritional quality have been achieved through the co valent attachment of amino acids by chemical or enzymatic modifications. The pharmacological area, the new one introduced i n this symposium, has been one of intense activity since 1975. Chemical derivatization of natural products such as endocrines has been used to control their utili zation i n the body. O n the other hand, fundamental studies of the specific chemical derivatization of enzymes by chemicals destroying their active sites is a rapidly expanding area of research. Some of these reagents, frequently looked upon as possible perfect target-specific drugs, have been called "suicide reagents" by some workers. I n the reactions of these suicide reagents, a chemical modification is actually an enzymatically driven process. Most readers w i l l probably agree that there have been extensive advances i n the fundamental areas of chemical and enzymatic modifica tions. The organizers do not expect similar agreements as to the success of the application of these methods i n food, nutrition, and pharmaco logical areas. This lack of agreement would be particularly evident for the eventual adoption of some methods for human use. Perhaps it w i l l be evident, however, that fundamental studies w i l l show what types of materials are required for human use and that, after proper research into the health and safety aspects, eventually some of these methods w i l l be applied for human use. The symposium organizers hope that our attempt to interrelate the different areas w i l l show the common thread running through them. W e apologize for any subjects that have been omitted and trust that the excuse of inadequate space for such a wide subject is understood. A n y lack of coherence between the chapters is certainly not the fault of the authors but could only be laid to the efforts of the organizers to empha size the ramifications. ROBERT E. F E E N E Y
Department of Food Science and Technology University of California Davis, California 95616 JOHN R . WHITAKER
Department of Food Science and Technology University of California Davis, California 95616 December 24,1980.
x Feeney and Whitaker; Modification of Proteins Advances in Chemistry; American Chemical Society: Washington, DC, 1982.
