By Dr. John Michaelides
By Dr. John Michaelides
Delving Into GMOs
This column is written by Dr. John Michaelides of the Guelph Food Technology Centre.
Question: What are genetically modified ingredients and how do they affect our bakery products and processes?
Answer: Genetically modified ingredients are produced from processing seeds, grains or other parts of plants or are derived from animals or micro-organisms that have been changed through genetic manipulation. As a result of these manipulations, we call these products genetically modified organisms or, for short, GMOs. Our ability to modify organisms and change their composition and characteristics or their ability to produce certain products is a result of hundreds of years of scientific observations and investigations. These investigations enable us to understand the genetics, biochemistry and physiology of the organisms based on the work of many great scientists such as Darwin and Mendel, who discovered and explained the hybridization between plants and established the laws which govern heredity and how the various traits are passed on from generation to generation. These efforts and discoveries led to the development of the classical and modern breeding techniques, which in turn has given us the crops we have been growing in today’s agricultural practices. Such practices allowed us to breed many new varieties of wheat, barley, oats, corn and many others. These varieties can produce greater yields, can be resistant to diseases or their seeds can contain higher proportions of certain important components such as protein, oil, starch, etc. The development of varieties with different traits using classical breeding techniques is, however, a long and tedious procedure and often random and non-specific. The next generation of transferring traits more efficiently and developing new varieties came with the invention of genetic engineering. The events that led to the introduction of genetic engineering are described below.
The discovery and elucidation of the DNA by Watson and Crick in the 1950s and the association of these molecules with the chromosomes provided the understanding of the genetic material at the molecular level. During that time it was also demonstrated that DNA transferred from one bacterium to another would result in the transfer of the donor traits to the recipient. However, it was not until the early ’70s that specific enzymes were used to cut and paste DNA pieces (of certain sequences) and splice them together to develop recombinant DNA or rDNA in test tubes. The process of genetic engineering involves the transfer of rDNA which has been spliced from the DNA of one organism into another. This process has been accelerated by the development of new technologies and appropriate tools that allow us to carry out such manipulations at the molecular and cellular level.
The first genetically modified crop to be developed was the soybean. In 1988, soybeans tolerant to glyphosate (herbicide) were developed by the insertion of a single gene that affected a specific enzyme within the plant. Other genetic modifications of soybeans include nutritional enhancement such as the introduction of a gene from Brazil nuts that enabled the soybean to produce a higher amount of the amino acid methionine. This variety, however, has not been commercialized due to concerns about the transfer of the allergenic protein from the Brazil nut. Today more than 70 per cent of the soybeans grown around the world are genetically modified. Many other crop species such as corn, canola, and sugar beets, as well as many greenhouse vegetables, have been modified using genetic engineering techniques. The next major crop to undergo genetic modification was corn, with the introduction of genes that enable the plant to produce the Bt (Bacillus thuringensis) protein, which is toxic to insects and specifically to certain pest species. In the early 1990s, StarLink corn was developed by introducing the Cry9c gene. However, due to regulatory uncertainties with regards to the resulting protein it was only approved for animal feed (at some point it contaminated the human food causing substantial food safety concerns). Since then, another Bt corn was developed by Pioneer Hi-bread International of DuPont, transferring the Cry1F gene, which did not pose any regulatory issues and was approved for use in United States and Canada. Other efforts in developing genetically modified crops have focused on resistance to micro-organisms and especially fungi. Major efforts are directed towards resistance to the Fusarium infection of wheat that will eliminate the issues of the Vomitoxin and other associated mycotoxins that end up in the wheat flour supply. Other efforts of using genetic modifications to enhance the safety of grains include the development by introduction of genes that will reduce the accumulation of toxic heavy metals such as cadmium in durum wheat. So far, no commercially grown genetically modified wheat is available in Canada, although tests have been carried out elsewhere in the world. Recently, Australia has given the go-ahead for field testing of a wheat variety that has been genetically modified to be tolerant to drought. The development of such modified crops is very important given the problems we are facing with the climatic changes that are currently taking place. Indeed, diversion of grain towards bio-fuels, combined with climate change, is resulting in substantial shortages of ingredients for food manufacturers. In turn, these shortages result in the subsequent escalating prices of crop commodities. In Australia, it is expected that grain prices will rise by over 20 per cent due to drought conditions that reduced yields by 50 per cent. Similar hikes are seen in the U.K., European Union, and elsewhere.
The possibilities of using genetic engineering to enhance the value of cereals and other commodities are endless. Many ingredients that are used in the baking industry may originate from plants or animals that have been genetically modified. These ingredients can range from flours, proteins, starches, and oils to other minor ingredients such as emulsifiers, gums and enzymes. Enzymes are quite often produced by micro-organisms that have been genetically modified. It’s very difficult to determine whether an ingredient is produced from a genetically modified organism and testing to do so is very costly. We rely on suppliers of such ingredients to inform us whether an ingredient is of GMO origin or not. If we are exporting products to countries that do not allow the use of such ingredients in their food supply it is our responsibility to ensure that we comply, and therefore testing may be necessary.
Genetic engineering provides the industry with powerful tools to modify plant crops, animals and micro-organisms, not only to produce specific and desirable ingredients but also to deal with such of the emerging challenges as climate changes and the associated pressure on crop production.
Dr. John Michaelides is director of research and technology for the Guelph Food Technology Centre. For more information, or fee for service help with product or process development needs, please contact the GFTC at 519-821-1246, by fax at 519-836-1281, or by e-mail at email@example.com.