For more than 100 years chemical engineers have used their unique expertise to conceive, design, test, and scale up revolutionary food-processing techniques.
Through their efforts we now expect exotic fruits and vegetables, fresh meats, seafood, and dairy products always to be available on our local grocery shelves. We have also come to depend on a bounty of safe, convenient processed foods to meet our nutritional and culinary needs.
At the dawn of agriculture, when our ancestors first started planting and harvesting, experiments with crop fertilization also began. Trial-and-error attempts to boost crop size eventually gave way to more focused applications of science and technology. Today synthetic and organic fertilizers significantly increase crop yields, while herbicides and pesticides help protect crops from damage.
Adding science to the soil
Soon after early civilizations began planting and harvesting, they initiated experiments to help maximize the yield of their crops. Efforts were focused on two general areas:
- Fertilization to promote growth and increase crop size, and
- Protection from pests and weeds to reduce damaged crops.
The use of natural nutrients to improve crops remained predominant until the Agricultural Revolution that began in the 19th century. At that time scientists began effectively applying their knowledge to help enhance crop production.
Most modern fertilizers stem from a chemical-engineering breakthrough pioneered by Fritz Haber in 1908. Haber, a chemist, engineered a process to synthesize ammonia through a reaction between hydrogen and nitrogen.
Haber’s discovery was so significant that he was awarded the Nobel Prize in Chemistry in 1918. Working with Carl Bosch, an industrial chemist, Haber designed and scaled up a successful process for cost-effective commercial-scale production of ammonia for use in nitrogen fertilizers. The Haber-Bosch process is considered by many to be one of the most monumental chemical-engineering achievements of all time because of its direct impact on sustainable global food production.
Pesticides and herbicides
In addition to developing new, more effective nitrogen fertilizers, chemical engineers are helping protect valuable crops against weeds, insects, and other pests. Chemical engineers have been instrumental in discovering and synthesizing many chemical compounds that function as pesticides to kill bugs and as herbicides to kill weeds. Chemical engineers also design the industrial processes necessary to produce these compounds on a commercial scale.
One such compound is glyphosate, the primary ingredient in Monsanto’s popular herbicide Roundup. It works by inhibiting a specific growth enzyme in plants. When applied to crops, glyphosate is rapidly metabolized by weeds. It also binds tightly to soil, so it does not accumulate in runoff and contaminate surface waters. According to the manufacturer, it eliminates more than 125 kinds of weeds but has no effect on mammals, birds, fish, or insects.
John Franz of Monsanto first discovered the herbicidal activity of glyphosate in 1970. In honor of the importance of his discovery, Franz received the National Medal of Technology in 1987, an award given to America’s leading innovators by the president of the United States. In 1990 Franz received the Perkin Medal for Applied Chemistry from the Society of Chemical Industry, America Section, and in 2007 he was inducted into the National Inventors Hall of Fame.
Taste and look
People have always looked for new ways to improve the flavor, texture, and appearance of food. Today an entire branch of chemical engineering is dedicated to applying science and technology to enhance the gustatory and visual appeal of the food we eat.
Enhancing the appeal
Chemical engineers have been working closely with food scientists to isolate and produce natural and artificial flavors and other food additives in commercial quantities. The ultimate result has been to create significantly more satisfying dining experiences.
Today an entire branch of chemical engineering is dedicated to food science and production. The unique, combined expertise of the scientists in this field has been directed toward:
- Improving food flavors and textures,
- Adding nutritional value, and
- Perfecting the appearance of foods.
Some of the most prominent breakthroughs have been in the areas of natural and artificial sweeteners and flavors. Foods have also been enhanced through innovative uses of different starches to improve texture and nutritional value.
Refined sugar is produced primarily from sugar cane or sugar beets and has long dominated the natural sweetener market. The commercial-scale production of refined sugar involves a variety of chemical-engineering operations, which include:
- Milling shredded raw materials and mixing with water,
- Adding chemicals to adjust the pH level to control the acid content,
- Removing impurities,
- Crystallizing the sugar and drying it, and
- Treating wastewater.
In recent years high-fructose corn syrup, made from cornstarch, has been used in foods and beverages. Production of corn syrup also requires many chemical-engineering operations, including:
- Dry milling the corn,
- Reacting the cornstarch with enzymes, and
- Purifying by ion exchange.
High-fructose corn syrup is valued by food processors because it tastes sweeter than refined sugar and is produced as a syrup, which makes it easier to blend into various foods and beverages.
Artificial sweeteners are novel chemical molecules that provide a sweetness level 500 to 600 times greater than that of traditional sugar. They are widely valued by calorie-conscious consumers and diabetics who need to limit their sugar intake. Considerable chemical-engineering expertise has gone into perfecting the processes needed to synthesize these compounds and produce them on a commercial basis.
The first commercial artificial sweetener was saccharin, discovered in the late 19th century. It is sold under the trade name Sweet’N Low. More recently aspartame, sold as Equal and the food additive NutraSweet, has gained popularity in the marketplace. And the latest artificial sweetener to be marketed is sucralose, sold as Splenda, which is actually made from sugar. Chemical engineers developed the commercial processes used to produce these low- or no-calorie sweeteners using numerous process innovations. Enjoy!
Starches from various sources are incorporated into processed foods as a major source of nutritional carbohydrates. Starches are also routinely added to foods to act as thickeners, to improve stability, and to provide a good “mouth feel” for the consumer.
Chemical engineers have played a key role in effectively isolating the desired starch from cereal grain seeds, roots, and tubers. They are also responsible for engineering complex systems to produce easy-to-use, free-flowing powdered starches in commercial-scale quantities.
Not too long ago the variety of foods available to consumers was limited to what could be produced and transported locally. This situation has changed thanks to modern packaging developed by chemical engineers that now allows us to savor a broad and bountiful selection of foods.
A cornucopia of protection
By developing novel packaging methods chemical engineers have helped expand the bountiful selection of fresher-tasting, longer-lasting foods we enjoy today. These modern packaging marvels run from basic to high tech and include:
- Traditional metal cans,
- Multilayer packages that allow heat sterilization right in the container, and
Packaging that controls oxygen and carbon dioxide levels to slow ripening and to reduce spoilage.
The protection provided by specialized packaging makes it possible for foods to be shipped over greater distances and stored on the shelf for longer periods. Protecting perishable foods - fruits, seafood, and meat—against spoilage and decay has helped connect distant food sources with new markets worldwide. We now expect to see strawberries, mangoes, and kiwi fruit in our markets year round. Among the more popular packaging methods being used are sterilization, vacuum packaging, and multilayered packaging.
To retard spoilage people have experimented with dehydration, smoking, salting, pickling, candying, and even the use of certain spices. It is now common knowledge that oxidation, bacteria, molds, and microorganisms cause foods to spoil and that sterilization can help prevent them.
Chemical engineers have helped devise many advanced sterilization techniques to preserve foods and protect consumers from food-borne illnesses. These procedures include:
- High-temperature pasteurization and canning,
- Refrigeration and freezing, and
Chemical engineers have been intimately involved in developing vacuum packaging. The food is placed into a gas-impermeable bag, the air is vacuumed out, and the bag is sealed. This process reduces the oxygen content inside the bag so that microbes cannot survive.
Later improvements on traditional vacuum packaging include controlled-atmosphere packaging (CAP) and modified atmosphere packaging (MAP), both of which represent monumental chemical-engineering breakthroughs in the field of food processing.
During CAP oxygen and carbon dioxide levels inside the food-packaging environment are controlled to limit fruit and vegetable respiration. This technique slows ripening and spoilage of fresh produce and prolongs the shelf life.
MAP is a more advanced version of CAP that not only slows ripening but also prevents many natural reactions that cause foods to become rancid and spoil.
Brick packs and retort pouches
The invention of chemically sterilized brick packs is another important chemical-engineering contribution to food safety and convenience. These multilayer packages are widely used to package juice, milk, tomato sauce, and countless other products to protect the contents from spoilage without the need for refrigeration. The ingenious brick-shaped package is typically constructed from high-quality paperboard, plastic, and aluminum.
More recently, flexible, laminated retort pouches have been widely used for food preservation. Multilayered retort pouches are filled with wet foods, sealed, and then heat treated to sterilize the contents. The food within the pouch is never exposed to air again until eaten, so it can be stored without refrigeration.
Prepackaged, frozen, fast-cook, dehydrated, and microwavable foods are among the developments that make our fast-paced modern lifestyle more palatable. These present-day time-saving conveniences have been brought forward largely through the efforts of the chemical-engineering community.
Fast and easy, delicious and nutritious
In an instant, heat and eat, just add water . . . and you’re on your way, fully fed. Our current fast-paced lifestyles have been supported by the development of a myriad of quick and tasty foods. Chemical engineers are largely responsible for first conceiving and then developing the many automated processes used to produce today’s easy-to-cook convenience foods.
Early efforts to produce fast-cooking rice, beans, and other legumes came with such nutritional tradeoffs as the removal of nutrient-rich outer bran layers. Chemical engineers developed imaginative food-processing techniques that allow highly nutritious brown rice, wild rice, beans and various crop seeds to be cooked quickly without sacrificing those outer layers.
The initial challenge was to produce frozen foods that retain their appearance, texture, taste, and nutritional content when thawed and cooked. Chemical engineers discovered that quick-freezing processes helped thawed foods retain all their freshness. The blanching of vegetables followed by quick freezing suppresses the enzymes that cause discoloration and the development of bad flavors.
Individually quick frozen processing was developed in the 1960s. It involves flash freezing pieces of food, which allows them to retain their natural characteristics when thawed.