By the year 2000 the worldwide market for biotechnology-derived food and agricultural products could be valued at tens to hundreds of billions of dollars. The results of the rapid pace of biological research since 1970 indicate that we are only scratching the surface of the potential.

We define biotechnology broadly, as the use of biological systems, including micro-organisms or components produced by micro-organisms, in industrial processes. Micro-organisms have been used in food preparation for centuries to preserve and transform raw agricultural commodities into edible products for human consumption.

Forecasts on Size of Worldwide Market for Biotechnology Agriculture and Food Processing Products
Source	Year	Millions Dollars
Arthur D. Little	1990	2,000–4,000
Business Communications Co.	1990	430
Policy Research Corp.	2000	50,000–100,000
Predicasts, Inc.	1985	6,200
	1995	101,000
Strategic, Inc.	1990	4,500
	2000	9,500
T.A. Sheets & Company	2000	21,300

Fermentation of milk, meat and fish, fruits and vegetables, and cereal grains by micro-organisms creates products which contribute to the flavor, texture and keeping quality of food, suppress the growth of disease and spoilage organisms, and enhance the nutritional quality of the final product. Fermentation is the use of enzymes produced by micro-organisms to change an organic compound into other substances such as carbon dioxide and alcohol. Fermentation technology also has been used for the microbial production of enzymes, amino acids, vitamins, and a host of other components used as food ingredients, nutritive supplements, and food processing aids.

In essence, the food processing industry was practicing biotechnology long before it was recognized as a distinct and revolutionary scientific discipline.

One facet of biotechnology of particular application in the food industry is genetic engineering. This technique is used in the laboratory to alter the genetic material of living cells so that they can produce more or different chemicals or perform new functions. It will have a profound impact on agriculture and traditional food processing because of the tremendous potential for genetic improvement of plants, animals and micro-organisms.

The interface between biotechnology and food processing was explored in October 1985 at an International Symposium, Biotechnology in the Food Processing Industry, cosponsored by the Department of Food Science and Nutrition and the Agricultural Experiment Station at the University of Minnesota, and the Cooperative State Research Service of the U.S. Department of Agriculture (USDA).

Now let us focus on the manipulation of micro-organisms in the production of food additives and processing aids, and their role in the development of value-added technology, improved processing methods, and more efficient use of food processing wastes. Many examples are from the symposium proceedings.

Food Additives and Processing Aids

Some of the products, including enzymes, amino acids, vitamins, organic acids, and certain complex carbohydrates and flavoring agents used in food formulation are currently produced by microbial fermentation. In the future, biotechnology will be used to design micro-organisms capable of producing these high-value additives more efficiently arid cost effectively. In addition, advances in large-scale fermentation systems and bioprocess design will optimize recovery arid downstream processing of microbial products. All of these will have a profound impact on the food industry.

Biotechnology Products for the Food Industry
Product	Use
Enzymes
amylase	High fructose corn syrup
isomerase
rennet	Cheesemaking
proteases	Meat tenderizer
pullulanase	"Lite" beer
Organic acids
citric acid	Acidulant
benzoic, probionic acid	Food preservative
Amino acids
methionine, lysine,trypthopan	Nutritional supplement
aspartic acid, phenylalanine	Aspartame production
Vitamins	Nutritional supplement
Low calorie products
aspartame, thaumatin, monellin	Non-nutritive sweeteners
modified fatty acids and triglycerides	Food additives and cooking oil
Microbial polysaccharides	Stabilizers, thickeners, gelling agents
Flavors and pigments	Flavoring and coloring agents
Single cell protein	Animal and human food supplement

Some food ingredients are extracted from plant material or synthesized chemically (i.e., gums, flavors, pigments). In the future it will be possible to transfer the genetic ability of the plant to synthesize certain flavors, pigments or complex carbohydrates into food-grade micro-organisms. This transfer will allow commercial production of these high-value food additives via fermentation processes.

Enzymes. The food processing industry is currently the largest consumer of industrial enzymes, making up about 40 percent of a $400 million market. An enzyme is a complex protein produced by living cells that helps a chemical reaction along without itself being changed. Enzymes are added during food processing to control texture or appearance, enhance nutritive value, and generate desirable flavors and aromas.

Future application of biotechnology will involve enzyme engineering—changing the primary structure of an enzyme. Such changes may alter target specificity, acidic condition, or thermostability. Enzyme engineering can be used to "tailor-make" enzymes to function best in commercial food processing systems.

Immobilized enzyme technologies have been developed for the production of high fructose corn syrup, and will have broad application in processing other foods. Immobilization of an enzyme increases its stability, allows easy separation of the product from the enzyme, and so facilitates its recycling.

In the future, immobilized enzymes will replace batch fermentations for producing amino acids, aspartic acid and tryptophan, and the non-nutritive sweetener, aspartame. Immobilization of rennet, the enzyme that coagulates milk during cheesemaking, or lactase, the enzyme which cleaves lactose to glucose and galactose, could speed the development of innovative continuous processing methods in the dairy fermentation industry.

Low Calorie Foods. The current trend toward a more health- and nutrition-conscious lifestyle has encouraged the development of low calorie foods. The non-nutritive sweetener market has been predicted to reach $500 million by the year 2000.

A new class of compounds called taste-active proteins functions as sweeteners and flavor modifiers and includes compounds such as aspartame, thaumatin, and monellin. The gene which codes for the protein thaumatin has been isolated and characterized. Transfer of this gene into bacteria would allow the production of thaumatin via fermentation. If engineered into plants, new and unique foods could be developed.

Another application of biotechnology in low calorie food production is the development of low calorie fats and oils. Genetically inducing the production of shorter chain fatty acids in soybean or rapeseed would speed the development of a low calorie vegetable oil. The market for this oil could reach $2 billion a year by the end of the next decade.

Natural Food Products. Another consumer trend is the demand for natural food products. Natural flavors and colors elicit a higher price than their synthetic counterparts, as the supply of these natural additives is highly dependent upon favorable environmental conditions for growing the plant and efficient and safe extraction procedures. Numerous strains of bacteria, yeast, and mold can produce flavors and colors of interest to the food processing industry. An understanding of the metabolic pathways and the specific proteins and enzymes responsible for the synthesis of these compounds will allow the future development of more consistent and cost-effective production methods.

Value-added Technology and Waste Management

A major concern in the food processing industry is the development of methods to convert inedible plant materials and waste materials into new value-added products. Each year the cheese industry generates billions of pounds of whey that must be disposed of. Ultrafiltration has provided the cheesemaker with a means of concentrating the protein component of whey into a value-added item with significant dollar value. Some solids, however, have a negative market value because it costs money to get rid of them.

A recently developed bioconversion system employing selected strains of yeast can convert these solids to ascorbic acid with a market value of about $10 per kilogram.

Certain strains of yeast can produce terpenes which impart a characteristic grape aroma and the odor of oils of interest in the wine and food industries. Because these strains use the lactose in whey as a sole carbon source, they could be used in fermentation systems to produce flavor components. The yeast biomass could be dried and used as single-cell protein supplements in animal feed.

Enzymatic treatment of food processing waste streams could produce materials readily metabolized by micro-organisms genetically engineered to produce antibiotics, hormones, or peptides of interest in the pharmaceutical or chemical industries. In the future, environmental and economic concerns will necessitate a reduction of food processing waste, better use of raw materials, and the processing of food residuals to new products that have value.

Rapid Detection Methods

Ensuring the safety of our food supply is an integral part of the food processing industry. Classical microbiological techniques for the enumeration and identification of disease agents and their toxins in foods are not always reliable and are often slow. Foods can already be in the marketplace before results are available. Biotechnology has been used to develop sensitive, reliable, and rapid detection methods to expedite this process.

One method involves DNA—deoxyribonucleic acid, the molecular basis of heredity in many organisms. Specific fragments of DNA from disease-causing micro-organisms that code for toxins or virulence factors have been used to create DNA probes which in hybridization analyses can detect those organisms in foods.

Commercial test kits for the detection of Salmonella are available and currrently being tested in field trials.

The identification of antigens by using monoclonal antibodies is another valuable tool in the biological monitoring of food. Monoclonal antibodies have been used to detect disease-causing micro-organisms, and they also help detect nonmicrobial components of food.

In the future, bioassays employing DNA probes and monoclonal antibodies will be developed for a host of food-borne disease agents and become a powerful diagnostic tool for the food processing industry.

Richard E. Lyng

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