GENETICALLY MODIFIED STARCHY FOOD AND POTENTIAL RISK OF ITS CONSUMPTION Piotr Tomasik Department of Chemistry, Agricultural University, Cracow

Genetically modified food Up to date, fortunately(?), only genetically modified plants are offered for consumption Goals offered by genetic modification: Higher yield of crops Higher thermal and mechanical properties Resistance to pests Better technological properties (higher lipid, protein, starch content, amylose/amylopectin ratio)

Key argument against genetic modifications: Mother nature has had several million years to develop the most beneficial forms of life and right pathways of living processes. All attempts of genetic modifications can appear to be harmful. Such arguments are serious and disputable. There are several facts immediately supporting that point of view, and there are „thin” contradicting facts. The latter are thin, because a long time is needed to prove them.

Excerpts from newspaper discussion „Ozon”: nr 1, , 2005, p. 37 Prof. Tomasz Twardowski, President of the Polish Biotechnological Federation GMO is more healthy than ecological food. GMO is safe because it is composed of the same components as normal food. It is safe based on numerous very thorough examinations (is the period of such examinations too short to justify such statement???!!!) Dr Zbigniew Hałat, President of the Polish Society of the Consumer Health Protection GMO causes allergies, for instance, several thousand Starling corn (the starchy plant) consumers, went to the court against its manufacturer for serious allergies they developed. Transgenic soy developed resistance to several antibiotics. GMO can be carcenogenic as it can propagate viruses used on modifications.

Experiment with a rat population A rat population was spread into two sub- populations. One of them was fed with GMO food and the other with normal food. After the experiment was completed, both sub- populations could not be combined together. Rats fed with GMO-free food did not accept those fed with the GMO food. What it means?

Starchy plants in nutrition Tubers: potato, patatas, tapioca (cassava, manioq), yams Wheats: wheat, rye, barley, oat, corn, rice, amaranthus, sorghum Other: beans, banana, sago All natural plants contain starches composed usually of 25% amylose and 75% amylopectin

Starch polysaccharides Amylose Amylopectin

Starch polysaccharides (continued) Amylopectin

Comparison of selected properties of both starch polysaccharides PropertyAmylose Amylopectin _________________________________ Mol. weight kDa kDa Aqueous solubility poor fair Complex with KI 5 blue purple Protein complexes - + Digesting enzymes 1,4- 1,4- & 1,6- Werner complexes +/- + Retrogradation fast (hours) slow (weeks)

Werner-type (metal) complexes Decrease [%] in conductivity [mS/cm] of 0.1 M aqueous solutions of metal chloride after admixture of starch polysaccharides ____________________________________ Metal saltAmylose Amylopectin Potato Corn ____________________________________ CoCl CuCl FeCl MnCl NiCl

Structure of starch granule and RS (Resistant Starch) crystalline layer Semicrystalline layer hilum granule Granule surface pore Crystalline layer Semicrystalline layer Amorphous channels blockle block lets Single blocklet Crystalline structure Amorphous layer Crystalline layer