Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/27/2001
Publication Date: 10/14/2001
Citation: Tilley, M. 2001. Effects of breadmaking on wheat DNA: implications for detection of genetically modified (gm) materials in processed foods. Abstract No. 364 in: 2001 AACC Annual Meeting Program Book. p.157. Meeting Abstract. Interpretive Summary: Presented at the International Wheat Quality Conference - II to be held in Manhattan, Kansas, May 20-24, 2001.
Technical Abstract: The use of genetically modified (GM) materials in foods is increasing. Labeling of such products will be dependent upon methods capable of sensitive and accurate detection. Detection of transgenic events can be based upon the detection of the novel proteins or their specific activities, DNA encoding the specific proteins, or DNA flanking the coding region sequences (e.g. promoter, terminator). DNA-based analysis is the method of choice due to the fact that DNA is highly stable and PCR-based analyses provide very high sensitivity and specificity. Processing steps have a profound effect upon the properties of proteins and DNA present in the final product. This project was designed to examine the effects of the breadmaking process on wheat DNA extracted from various steps in the process. Samples were taken from wheat kernels, milling fractions, flour, fully mixed dough, 1st punch, 2nd punch, moulding, pan stages, during bake (5, 10, and 15 min) and after bake (1, 3, and 5 days). Total DNA was purified, quantified spectrophotometrically and integrity was evaluated on ethidium bromide stained agarose gels. DNA purified from kernels demonstrated intact high molecular weight DNA (>12 kilobase pairs - kb), whereas that from flour exhibited a broad smear of DNA ranging from >12 kb to <0.3 kb. DNA purified from bread exhibited a smear with a maximal size of 0.4 kb with an average size of 0.2 - 0.3 kb. Samples were utilized in PCR reactions to amplify products representative of gene sequences present at different copy numbers within the wheat genome. Discussion of results will be included in the poster presentation.