Genetic modification and wheat milling

by Teresa Acklin
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Genetically modified wheat offers possibilities for increased efficiency and improved milling profits.

By David Sugden

   Vast investments have been made into plant genetics with increased agricultural output as the goal, but research on genetic modification of grain for functional and processing reasons is still in its infancy. Most of the money for genetic research so far has been channeled into production because of expected population growth, which will demand higher efficiencies and yields to counter starvation and consequent political problems.

   But the processing, functional and nutritional characteristics of grains, including wheat, offer a wide variety of possibilities for genetic research, and the science to develop these facets is here today. It is hard to escape the conclusion that the biggest single change over the next 20 to 30 years will be the use of genetically modified wheat and the consequences for the wheat-based industries.

   Genetic manipulation, modification or engineering is a technique that is rapidly replacing plant breeding. Scientific techniques essentially allow the isolation and manipulation of a single identified desirable or undesirable gene out of many thousands to produce a sought-after improvement. Compared to plant breeding, where it may take 15 years to produce grain capable of reaching fruition, genetic engineering cuts that time by at least half.

   The two best known examples of genetically modified grains are the so called “Round-Up Ready” soybean and “Bt Corn.” The former is resistant to the herbicide “Round-Up,” and the latter is resistant to the European corn borer.

   Both already are used in the United States, and it has been estimated that some 54% of U.S. soybean plantings and 51% of maize area by 2001 will consist of genetically modified seed, compared with 1998 levels of 20% and 11%, respectively (see January 1998 World Grain, page 24). Thus, the effect of genetically modified organisms (G.M.O.s) already is profound, and G.M.O.s have significant momentum.

      Wheat Composition

   Wheat so far has been much less studied because it is more complex. The limit is partly one of the imagination and partly that of funding — the science and the return on investment.

   The classical diagram of a lengthwise cut-away and peeled-back wheat kernel illustrates the principal constituent parts. The approximate composition of wheat, simplified, is shown in the accompanying table.

   But what is about to happen or is now in the planning stages from the standpoint of flour millers or processors? The following possibilities are advanced with G.M.O.s in mind.

   A creaseless wheat kernel has been desired by millers from the earliest times in order to grind more efficiently. The benefits include simplified mill diagrams, less machinery, lower capital cost, reduced maintenance, greater extraction, less energy and therefore, greater return on investment. The technique of debranning would come into its own even more.

   Whiter endosperm would allow longer extraction, giving financial gain.

   Thinner wheat skin (bran) would offer the same benefits as whiter endosperm. Larger germ would facilitate the marketability of valuable germ oil on a more economic basis with its clear nutritional properties of high protein and a rich source of vitamin E.

   Lower mineral content and harder wheat, within reason, would make for easier milling and better yields both for bread flours and pasta making, with consequent gains financially.

   Uniform kernel size would result in a reduction in both the numbers and types of machines, meaning lower investment and cost.

   High starch content could open the way for a dry, as opposed to a wet, process for starch extraction. The current problem is the enormous comparative capital and energy cost associated with wet separation.

   High gluten content could have advantages similar to high starch content, plus the benefit of specialty products for the downstream industries of bread and pasta.

   Reduced alpha amylase content, particularly in a bad harvest year, would help the major wheat-based industries to use larger proportions of cheaper crops when so damaged.

   A lysine increase would open the possibility for wheat to compete more easily with coarse grains and proteins of animal origin on a nutrition basis. Wheat is comparatively short of this essential amino acid, which cannot be synthesized by the body.

   The shelf life of freshly baked goods or fresh pasta for example, could be increased, therefore reducing cost in those industries by means of better scheduling and longer shelf runs. This is another issue well-known for its classical difficulties over time.

   Fiber increase would bring targeted nutritional gains.

   Calorie and cholesterol control would be envisaged for dietary and nutritional possibilities.

   Peroxidase and polyphe-noloxidase decrease, in durum wheat particularly, would aid the attainment of better amber color for finished pasta goods. This could mean upgrading of lesser value durum crops.

   Modified starches for food and industrial uses can be imagined in this very wide field leading to cheaper products with reduced chemical input.

   And so the list will mount. One caveat that food manufacturers will be all too aware of — products must be acceptable organically to consumers or else sales will fail.

      Risks And Trade Approaches

   Examples of risks cover a broad field. Some are real, some perceived. Suffice it to say that G.M.O.s are here to stay. It is the control, if that is the right word, that is creating political problems, particularly in the European Union and Western Europe.

   Chastened by unrelated scares — highlighted by the worst food disaster in history to hit the United Kingdom (B.S.E. or mad cow disease) — many in Britain and Europe have reacted by rejecting any so-called tinkering with nature. The fears raised by the recent scares need not apply to G.M.O.s if the public is educated and informed, wherever they live.

   Concerns, right or wrong, already listed for G.M.O.s include unexpected allergies, toxins, evolution of herbicide and pesticide resistant weeds, salt tolerant crops growing on salt marshes, irreversible consequences, antibiotic gene transfers from G.M.O.s into the food chain and the segregation of G.M.O. and non-G.M.O. supplies. This last is surely impossible.

   So the European Union, for instance, is encouraging member states to label goods on grocery shelves with such words as “may contain a proportion of [G.M.O.]” or “made from genetically modified material” and so on. Checks and balances are in place; whether they will work only time will tell.

   The major food and agrochemical companies are very active in G.M.O. research and marketing. Trade associations are inactive, or barely involved, because of commercial secrecy, competition and possible patents.

   Some may see fantasy in genetic modification. However, the science and the will to exploit it are here. The pendulum is swinging steadily towards the maximization of G.M.O.s for processing, including wheat milling, and eventually leading through the chain to the consumer.

   David Sugden, independent consultant to the grain industries, may be reached at The Coach House, Killigrews, Margaretting, Ingatestone, Essex CM4 0EZ, U.K. Tel: 44-1245-352048. Fax: 44-1245-251162.

Approximate composition of wheat

(in percent)
Starch (by difference)60.0-68.0
Protein (N x 5.7)8.0-15.0
Fiber (cellulose)2.0-2.5
Fat (oil)1.5-2.0
Mineral matter (ash)1.5-2.0
Source: Modern Cereal Chemistry