Nutritional improvement of food and feed proteins

The nutritional quality of a protein depends on the proportion of its amino acids-especially the essential amino acids-their physiological availability, and the specific requirements of the consumer. Availability varies and depends on protein source, interaction with other dietary components, and the consumer's age and physiological state. In many foods, especially those from plants, low levels of various essential amino acids limits their nutritive value. This is particularly important for cereals (which may be inadequate in the essential amino acids isoleucine, lysine, threonine, and trytophan) and legumes (which are often poor sources of methionine). Moreover, these commodities are principle sources of protein for much of the earth's rapidly growing population. At the current annual growth rate of about 2 percent, the world population of about 4 billion will increase to 6.5 billion by the year 2000 and to 17 billion by the year 2050. Five hundred million people are presently estimated to suffer protein malnutrition, with about fifteen thousand daily deaths. The ratio of malnourished to adequately nourished will almost surely increase. For these reasons, and especially in view of the limited availability of high quality (largely animal) protein to feed present and future populations, improvement of food and feed quality is especially important. The key questions in my mind are "What may or will happen if we do not develop new and improved food and feed sources? What are the consequences of population pressures for our future wellbeing?" In his analysis of the subject, Robert R. Heilbronner (An Inquiry into the Human Prospect, W.W. Norton, 1975) foresees dire prospects which include: (a) rule of the world by military socialist dictatorships; (b) seizures of weak nations by strong ones; (c) use of nuclear blackmail by underdeveloped countries to transfer wealth; and (d) deterioration of the environment, whereby exponentially growing emission of man-made heat will cause drastic climactic changes and major decreases in industrial and agricultural production. In a related analysis (Engineering Science, pp. 22-36, 1956), Sir we do not develop new and improved food and feed sources? What are the consequences of population pressures for our future wellbeing?" In his analysis of the subject, Robert R. Heilbronner (An Inquiry into the Human Prospect, W.W. Norton, 1975) foresees dire prospects which include: (a) rule of the world by military socialist dictatorships; (b) seizures of weak nations by strong ones; (c) use of nuclear blackmail by underdeveloped countries to transfer wealth; and (d) deterioration of the environment, whereby exponentially growing emission of man-made heat will cause drastic climactic changes and major decreases in industrial and agricultural production. In a related analysis (Engineering Science, pp. 22-36, 1956), Sir Charles Darwin also suggests that man will come to a 'semi-bestial' existence (his grandfather did not have this type of 'evolution' in mind when he wrote origin of species and The Descent of Man). Although Fred Hoyle (ibid., pp. 8-10) and Robert Heilbronner suggest that human negative feed-back processes will exercise a dampening effect on the impending crisis, such feed-backs may not suffice to prevent it. (A result of important feed-back processes is the differential growth rate of the world's population. Western Europe, the United States, and apparently also the Peoples Republic of China, seem to be approaching true zero growth, in contrast to Latin America, Africa, and most other parts of Asia, which are growing by 2 to 3 percent annually). We are, therefore, challenged to respond to humanity's common danger. I feel that as scientists interested in proteins in all aspects, we are indeed responding to this challenge. Aside from limiting population growth, which is a sociological and political problem, our work as agronomists, plant breeders, animal scientists, food chemists, food technologists, nutritionists, dietitians, physicians, toxicologists, agricultural economists, and industrialists can help avoid and alleviate shortages of high quality foods and feeds and thus counter and mitigate some of the more serious threats to the quality of life for ourselves and our descendants. Our objective should be to improve the quality and quantity of available food and feed sources by all feasible methods. Much new chemistry and engineering is needed to support genetics and agronomy. Food fortification and supplementation need better guidance based on research. Deleterious side reactions in food storage and processing need to be eliminated or minimized. Ways to measure protein nutritional quality based on information from chemical, biochemical, microbiological, animal, and human studies need to be correlated and optimized. New protein food sources need to be developed; related toxicological and nutritional problems need solutions. Because I feel that the most important function of a symposium is dissemination of insights and catalysis of progress by bringing together ideas and experiences needed for synergistic interaction among different, yet related disciplines, in organizing the Symposium on "Improvement of Protein Nutritive Quality of Foods and Feeds" (sponsored by the Protein Subdivision of the Division of Agricultural and Food Chemistry of the American Chemical Society, Chicago, Illinois, August 29-September 2, 1977), I invited papers discussing one or more of the following topics: (1) Improvement of protein quality by genetic methods; (2) Fortification of foods and feeds with essential amino acids, amino acid analogs, or derivatives; (3) Enrichment of foods and feeds with protein supplements; (4) Use of special processes such as the plastein reaction to maximize protein quality and utilization; (5) Use of protected amino acids and proteins in ruminant feeds to increase meat, milk, and wool production; (6) Chemical and microbiological syntheses of essential amino acids; (7) Interactions ingrei such i calcu: and fE avails Safet3 incluc papers specia a hybr contritions of supplemental amino acids or proteins with other food ingredients during storage and processing and ways to minimize such undesirable interactions; (8) Economic aspects, including calculation of least cost-optimum quality supplemented foods and feeds; (9) Animal and human feeding tests of nutritional availability of amino acids or proteins in supplements; and (10) Safety of supplemented or specially processed foods and feeds, including amino acid antagonisms in vivo. In addition, many scientists accepted invitations to contribute papers to this volume. Indeed more than half the papers are specially written, invited contributions. This book is, therefore, a hybrid between a symposium proceedings and a collection of invited contributions. This volume brings together outstanding international authors from ten countries, who, in forty papers, thoroughly discuss various ways to improve foods and feeds. Though an adequate summary is not possible in a preface, I wish to call special attention to several manuscripts. First, F. Monckeberg and C. 0. Chichester describe in a particularly enlightening way the interdependent efforts among several scientific disciplines, government agencies, and industry to successfully develop a fortified food formula for children in Chile. Related discussions of nutrition intervention programs in Guatemala are ably presented by R. Bressani, L.G. Elias, and J.E. Braham, and in India, by R.P. Devadas.