title: Quantitative determination of Roundup Ready soybean (Glycine max) extracted from highly processed flour.
abstract: Roundup Ready soybean powder has been subjected to different amounts of DNA fragmentation to assess the accuracy of real-time PCR on processed food. Certified reference material (CRM) containing 10 g kg(-1) of Roundup Ready soybean (ERM-BF410d) prepared by a dry-mixing processing method was exposed to water at two temperatures, using three different mixing devices, or to baking temperature (250 degrees C) for 30 min. The amount of DNA extracted from the different samples was quantified by fluorimetry. The amount of fragmentation of the extracted DNA was characterised by gel and capillary electrophoresis and the percentage of genetically modified (GM) soybean was determined by a double quantitative real-time PCR method. Measurement of the event GTS 40-3-2 (RUR) was possible in all the treated materials, because small amplicons were amplified. Correct RUR percentages could be measured for intact powders with little or no DNA fragmentation. For samples with a high level of DNA degradation, however, the accuracy of the measurement was found to depend on the method used for DNA extraction. Genomic DNA isolated by use of silica resin resulted in statistically significant overestimation of the amount of GM.
authors.affiliation: Institute for Reference Materials and Measurements, European Commission, Joint Research Centre, Retieseweg 111, 2440, Geel, Belgium. philippe.corbisier@cec.eu.int
authors.forename: Philippe
authors.initials: P
authors.lastname: Corbisier
authors.forename: Stefanie
authors.initials: S
authors.lastname: Trapmann
authors.forename: David
authors.initials: D
authors.lastname: Gancberg
authors.forename: Liesbeth
authors.initials: L
authors.lastname: Hannes
authors.forename: Pierre
authors.initials: P
authors.lastname: Van Iwaarden
authors.forename: Gilbert
authors.initials: G
authors.lastname: Berben
authors.forename: Heinz
authors.initials: H
authors.lastname: Schimmel
authors.forename: Hendrik
authors.initials: H
authors.lastname: Emons
mesh_terms: D004247:DNA / Q000032:analysis*; D053938:DNA Fragmentation; D019075:Electrophoresis, Capillary; D004591:Electrophoresis, Polyacrylamide Gel; D005433:Flour / Q000032:analysis*; D005470:Fluorometry; D016133:Polymerase Chain Reaction; D012825:Silicon / Q000737:chemistry; D013025:Glycine max / Q000737:chemistry* / Q000235:genetics; D013696:Temperature; D013997:Time Factors
chemical_list: D004247:DNA; D012825:Silicon