Enzymes, nature's key to life, drive everything from bacteria to humans; they are now being widely used in food processing.

Enzymes, specialised protein molecules in living organisms, behave as catalysts in chemical reactions. They change the rate of a chemical reaction without changing themselves. Essential in the metabolism of all living things, they can also be used independently, to drive chemical reactions. They have been used (at first unwittingly) for thousands of years, due to the role of microbes in the production of food and alcohol. Their efficiency, specificity, and environmental friendliness has lead to their increased use in food processing, as well as many other branches of manufacturing industry.

Enzymes come of age

Recently, the advent of biotechnology has allowed further refinement of the use of enzymes in food processing, offering solutions to many persistent problems as well as opening up many exciting new possibilities. Today a wide range of purified enzymes are used. Perhaps the most striking example of the advantages of modern enzyme technology is the breakdown of starch to sugars. This process originally involved boiling the starch with acid, requiring large energy inputs and producing undesirable by-products. In contrast, the enzyme process takes place in mild conditions, saving energy and preventing pollution.

It was not until the mid 1950's that rapid developments in enzyme technology occurred. The development of biochemistry led to a fuller understanding of the wide range of enzymes present in living cells and of their mode of action. Extracting or isolating enzymes from microbes for example, increased their efficiency. Purified enzymes do not lose their properties, on the contrary, these "cell-free" preparations work even more efficiently.

Nutrition for babies

A recent development which is highly significant to pregnant women, involves nutrition for premature babies whose particular nutritional requirements are not fully satisfied by traditional existing preparations. Palmitic acid is the most abundant fatty acid in mother's milk and most of it occurs in a form that allows it to be absorbed and used by the baby. Traditional existing preparations originally contained a form of palmitic acid that could not be used by the baby and also caused loss of calcium for bone synthesis.

The enzyme alpha lipase, produced by genetically modified Aspergillus mould, can now be used to produce the natural form of palmitic acid for milk preparations for premature babies. The beneficial impact on saving premature babies has been significant.

Enzymes at work in your food

Rennet, an enzyme preparation traditionally derived from the stomachs of young farm animals, is the original means of coagulating milk in cheese making. Over the last thirty years, several substitutes for rennet have been developed, allowing the supply of enzymes to keep pace with cheese production and providing an alternative product for vegetarians. Some of these enzymes are derived from fungi. The latest developments, made possible by modern biotechnology, is the production of calf chymonsin by a genetically modified yeast. In the UK, the Vegetarian Society has given this cheese, made with yeast-derived enzyme, its seal of approval.

Modern enzyme technology helps prevent waste. It allows for example, the use of surplus whey from cheese making. The enzyme lactase converts the lactose sugar in whey into a sweet tasting mixture of glucose and galactose. The product is refined and concentrated into honey-like syrup that has a wide range of applications in the confectionery industry.

Several other enzymatic treatments are involved in producing modern sweeteners. For instance, high-fructose syrup from corn starch has now eclipsed sucrose as the major sweetener used in the US food industry.

For more information, refer to the EUFIC leaflet on "Enzymes in Food" to be published soon.

Green and efficient

Enzymes have many other applications in modern food processing. Their properties benefit both the food industry and the consumer. Their specificity offers food producers much finer product control, while their efficiency, requiring low energy inputs and mild conditions, has distinct environmental advantages. They can be used to treat biological waste from food processing, and are themselves biodegradable, being readily absorbed back into nature. They are exemplary agents of green technology.

Genetic modification - tested, tested, and tested again

No traditionally bred crop varieties undergo such stringent testing prior to marketing as crops and foods produced with the help of modern biotechnology.

There is nothing new in the transfer of results from science to industry and agriculture. The concept of acceptable risk is intrinsic to the notion of pushing back the frontiers. This also applies to the use of biotechnology in agriculture.

The proven economic and ecological potential of genetically modified crops explains the great interest of farmers and the food industry in modern biotechnology. Its ability to play an important role in sustainable production and the development of future world food supplies is clear. Indeed, the increasing need to supply a steadily growing world population with food demands new solutions. Genetic modification of plants has been accepted by specialists as an inexpensive and environmentally friendly way of producing food. However, such new techniques may raise questions from the general public regarding safety and reliability.

The biotechnology industry is aware of these concerns and is becoming more open in dealing with the queries of different interest groups. Questions cover topics such as:

• Is food containing genetically modified organisms safe? (see Food Today No. 2)
• Can genetically introduced genes in plants transfer to existing species in the environment? (See Food Today No. 3)
• Can human allergies be caused by gene transfers from one organism to another? (Article coming soon in Food Today)

Stringent controls

Many of the issues raised have been comprehensively addressed by experts in the field of biotechnology. Before a product is approved, it undergoes extensive testing. These tests include detailed evaluation of the safety of the organisms involved; analysis of "substantial equivalence" i.e. comparison of the new plant varieties and derived foods with their traditional counterparts; and testing for allergenic potential. Bernard Guy-Grand, professor of nutrition at the Hôtel Dieu hospital in Paris says, "few foodstuffs are subject to such a degree of control... The approval process required for genetically modified crops is comparable to that for medical products."

FOOD TODAY 04/1998