Synthetic and Artificial Food Products
Synthetic and Artificial Food Products
food products, generally of high protein content, produced by new technological methods from such nutritive substances as proteins or their component amino acids, carbohydrates, fats, vitamins, and trace elements. Synthetic and artificial food products usually imitate natural food products in appearance, taste, and odor.
Synthetic food products are derived from chemically synthesized food substances. In principle, modern synthetic organic chemistry permits the synthesis of any food substance from chemical elements. However, the complexity of synthesizing high-molecular-weight compounds, which include food bio-polymers, especially proteins and polysaccharides (starch and cellulose), makes the production of synthetic food products economically unfeasible at present. For this reason, chiefly low-molecular-weight compounds, such as vitamins and amino acids, are synthesized. Synthetic amino acids and combinations of them are added to natural food products to increase their protein content and are also used in dietotherapy, for example, in the intravenous feeding of patients when normal eating is difficult or impossible.
The world has an inadequate supply of complete food protein, that is, protein containing all the essential amino acids, or those not synthesized by the body. This shortage affects three-quarters of the earth’s population and confronts mankind with the unavoidable problem of finding abundant, accessible, and inexpensive sources of complete protein for enriching natural foods and manufacturing new, artificial food proteins. Artificial food products (food proteins) are those rich in complete protein derived from natural food substances. Such food products are obtained by combining solutions or dispersions of these food substances with gelling agents and treating the resulting mixture so as to obtain the desired structure and shape.
At present, proteins from two major sources are used as the basis of artificial food products. One source is nontraditional plant and animal foodstuffs. These include soybeans, peanuts, sunflower seeds, cottonseed, sesame, rapeseed, oil cake and meal from these seeds, peas, wheat gluten, and green leaves and other green material from plants. Animal proteins utilized are derived from casein, trash fish and krill, and other marine sources.
The other major source is synthesized by microorganisms, particularly yeasts. Yeasts synthesize protein at a remarkable rate and can grow both on food mediums, such as sugar, wort, and oil cake, and on nonfood mediums, such as petroleum hydrocarbons. Yeasts are thus a promising and virtually inexhaustible source of artificial food products. However, the wide use of microbiological sources requires the development of efficient methods for obtaining and processing highly purified proteins and also demands thorough medical and biological research. In this connection, it may be noted that the protein of yeasts grown on agricultural wastes and petroleum hydrocarbons is used mainly in the form of nutrient yeast, a dietary supplement for farm animals.
The idea of deriving synthetic food products from chemical elements and of obtaining artificial food products from lower organisms was advanced in the late 19th century by D. I. Mendeleev and by P. E. M. Berthelot, one of the founders of synthetic chemistry. However, practical application became possible only in the 1950’s owing to advances in molecular biology, biochemistry, physical and colloid chemistry, and physics. The technology of processing polymer fibers and films had improved, and high-precision physicochemical methods had been developed for the analysis of multicomponent blends of organic compounds; among such methods were spectroscopy and gas-liquid, and other types of chromatography.
In the USSR, extensive research on artificial food proteins was begun in the 1960’s and 1970’s on the initiative of Academician A. N. Nesmeianov at the Institute of Heteroorganic Compounds of the Academy of Sciences of the USSR. This research has developed in three major directions. Economically feasible methods are being devised for obtaining isolated proteins as well as amino acids and combinations of them from plant, animal, and microbial sources. Methods are being developed for fabricating combinations of proteins and protein and polysaccharide complexes into artificial food products whose texture and appearance resemble those of traditional food products. Finally, natural food odors are being studied, and methods of artificially re-creating their composition are being developed.
The methods developed for obtaining purified proteins and combinations of amino acids are the same for all types of sources. The cell membrane is destroyed by mechanical or chemical means and the protein and other cell components (polysaccharides, nucleic acids, and complexes of lipids with vitamins) are extracted by means of fractional dissolution and precipitation. The proteins are split by enzymatic or acid hydrolysis, and the hydrolysate produces a combination of amino acids that is purified by means of ion-exhange chromatography and other methods.
Texturization studies have made it possible to produce from a combination of proteins and protein and polysaccharide complexes all the basic structural elements of natural food products: fibers, membranes, and rehydratable texturized sheets made of macromolecules.
Methods have also been developed for producing artificial caviar and foods that simulate meat, potatoes, macaroni products, and groats. Thus, proteinaceous artificial caviar is made from the high-quality milk protein casein. An aqueous solution of casein is mixed, together with a texturizer such as gelatin, into chilled vegetable oil, resulting in the formation of particles resembling fish eggs. The particles are removed from the oil, washed, coated with tea extract to impart an elastic membrane, dyed, and treated with solutions of acid polysaccharides to form a second membrane. Salt and flavoring and aromatizing substances are added, resulting in a proteinaceous delicacy virtually indistinguishable from natural caviar.
Artificial meat suitable for any manner of culinary preparation is produced by the extrusion (forcing through a die) and wet spinning of protein to convert it into fibers. The fibers are then formed into a ropelike tow, washed, impregnated with a protein binder, pressed, and fabricated into pieces. Artificial fried potatoes, vermicelli, rice, whole buckwheat, and other nonmeat products are obtained by combining protein with natural food materials and such gelling agents as alginates, pectins, and starch. Equal in their organoleptic properties to the corresponding natural products, these artificial food products are five to ten times richer in protein and possess superior technological properties. In modern technology, odors are studied by gas-liquid chromatography and artificially reproduced from the same components as those in the natural food products.
Research on the production of synthetic and artificial food products is conducted in the USSR at the Institute of Heteroorganic compounds of the Academy of Sciences of the USSR in conjunction with the Institute of Nutrition of the Academy of Medical Sciences of the USSR, the G. V. Plekhanov Moscow Institute of the National Economy, the Scientific Research Institute of Public Nutrition of the Ministry of Trade of the USSR, the All-Union Scientific Research and Development Institute of Food-industry Machine Building, and the All-Union Scientific Research Institute of Marine Fisheries and Oceanography. Methods of manufacturing artificial food products are being developed with the aim of introducing laboratory models into industrial production.
Outside the USSR, the first patents for producing artificial meat and meatlike products from soybean, peanut, and casein proteins were obtained in the USA by Anson, Pader, and Boyer between 1956 and 1963. A new industry subsequently developed in the USA, Japan, and Great Britain for the production of many artificial food products. These included fried and ground meats, meat aspics, broths and patties, sausages, frankfurters, and other meat products. Among other artificial foods developed were bread, macaroni and groats products, milk, cream, cheeses, candies, berries, beverages, and ice cream.
In the USA, which grows almost 75 percent of the world’s crop of soybeans, the production of artificial food products from soy protein has reached hundreds of thousands of tons. In Japan and Great Britain, artificial food products are made primarily from plant proteins. The preparation of artificial milk and cheeses from green leaves has begun experimentally in Great Britain, and the manufacture of artificial food products is being undertaken in other countries. According to foreign statistics, by 1980 or 1990 the production of artificial food products in economically developed countries will constitute ten to 25 percent of the production of traditional food products.
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S. V. ROGOZHIN