Analysis of Genetically Modified Food Using High-Performance Separation Methods

Characterization and study of transgenic cultivars by capillary and microchip electrophoresis

Advances in biotechnology have increased the demand for suitable analytical techniques for the analysis of genetically modified organisms. Study of the substantial equivalence, discrimination between transgenic and non-transgenic cultivars, study of the unintended effects caused by a genetic modification or their response to diverse situations or stress conditions (e.g., environmental, climatic, infections) are some of the concerns that need to be addressed. Capillary electrophoresis (CE) is emerging as an alternative to conventional techniques for the study and characterization of genetically modified organisms. This article reviews the most recent applications of CE for the analysis and characterization of transgenic cultivars in the last five years. Different strategies have been described depending on the level analyzed (DNA, proteins or metabolites). Capillary gel electrophoresis (CGE) has shown to be particularly useful for the analysis of DNA fragments amplified by PCR. Metabolites and proteins have been mainly separated using capillary zone electrophoresis (CZE) using UV and MS detection. Electrophoretic chips have also proven their ability in the analysis of transgenic cultivars and a section describing the new applications is also included.

Comparison of three modifications of fused-silica capillaries and untreated capillaries for protein profiling of maize extracts by capillary electrophoresis

In this work, capillary electrophoresis was applied to protein profiling of fractionated extracts of maize. A comparative study on the application of uncoated fused-silica capillaries and capillaries modified with hydroxypropylmethylcellulose, ω-iodoalkylammonium salt and a commercially available neutral capillary covalently coated with polyacrylamide is presented. The coating stability, background electrolyte composition, and separation efficiency were investigated. It was found that for zeins separation, the most stable and efficient was the capillary coated with polyacrylamide. Finally, the usefulness of these methods was studied for the differentiation of zein fraction in transgenic and nontransgenic maize. Zeins extracted from maize standards containing 0 and 5% m/m genetic modification were successfully separated, but slight differences were observed in terms of the zein content. Albumin and globulin fractions were analyzed with the use of unmodified fused-silica capillary with borate buffer pH 9 and the capillary coated with polyacrylamide with phosphate buffer pH 3. In the albumin fraction, additional peaks were found in genetically modified samples.

Food Analysis: Present, Future, and Foodomics

This paper presents a revision on the instrumental analytical techniques and methods used in food analysis together with their main applications in food science research. The present paper includes a brief historical perspective on food analysis, together with a deep revision on the current state of the art of modern analytical instruments, methodologies, and applications in food analysis with a special emphasis on the works published on this topic in the last three years (2009–2011). The article also discusses the present and future challenges in food analysis, the application of “omics” in food analysis (including epigenomics, genomics, transcriptomics, proteomics, and metabolomics), and provides an overview on the new discipline of Foodomics.

Proteome changes in tomato lines transformed with phytoene synthase-1 in the sense and antisense orientations

The commercial cultivation of genetically engineered (GE) crops in Europe has met with considerable consumer resistance, which has led to vigorous safety assessments including the measurement of substantial equivalence between the GE and parent lines. This necessitates the identification and quantification of significant changes to the metabolome and proteome in the GE crop. In this study, the quantitative proteomic analysis of tomato fruit from lines that have been transformed with the carotenogenic gene phytoene synthase-1 (Psy-1), in the sense and antisense orientations, in comparison with a non-transformed, parental line is described. Multidimensional protein identification technology (MudPIT), with tandem mass spectrometry, has been used to identify proteins, while quantification has been carried out with isobaric tags for relative and absolute quantification (iTRAQ). Fruit from the GE plants showed significant alterations to their proteomes compared with the parental line, especially those from the Psy-1 sense transformants. These results demonstrate that MudPIT and iTRAQ are suitable techniques for the verification of substantial equivalence of the proteome in GE crops.