Mikrodalga Uygulanan MIR604 ve MON810 Mısır Unlarının Omik Yaklaşım ile Karakterizasyonu
Özet
The omics approach in food science provides researchers with robust, efficient, and sensitive analytical tools for characterizing and evaluating food components and nutrients. The application of processing technologies, such as microwave technology, and their effects on food components have been studied and adopted by the food science and industry. In this thesis, the aim was to perform the molecular and chemical characterization of MIR604 and MON810 maize flours, along with their non-genetically modified (GM) counterparts, before and after microwave treatment, using omics approaches (genomics, transcriptomics, metabolomics, and lipidomics), and to evaluate the obtained data with appropriate statistical tools. With the findings, important information has been presented to establish a background for the characterization of molecular and chemical components in maize flour samples, depending on the process effect.
In genomics, screening methods were applied to samples for the detection of GMOs using DNA-based techniques. Qualitative polymerase chain reaction (PCR)-based screening method was used to detect Cauliflower mosaic virus (CaMV) 35S promoter (P-35S), Figwort mosaic virus promoter (P-FMV), and T-NOS (nopaline synthase terminator) sequences in the samples. The effectiveness of DNA extraction was confirmed by an inhibition study for Actin (ACT) gene. Verification studies of screening analyses were performed by determining both the absolute limit of detection (LODabs) and the type 1, type 2 error rate parameters. In transcriptomics, the expression profiles of the Argonaute (ZmAGO1a) and Receptor-like protein kinase (ZmRLK9) enzyme genes were revealed by RNA-based analysis to examine the effect of microwave treatment. These two genes were detected with EvaGreen-based reverse transcription-quantitative PCR (RT-qPCR) analyses, and their absolute gene expression profiles were examined. The effectiveness of RNA extraction method was determined by verification study for Alcohol dehydrogenase (ZmADH1) gene. Calibration curves were constructed, and verification parameters (amplification efficiency, specificity, reproducibility standard deviations, limit of detection (LOD), and quantification (LOQ)) were evaluated.
In metabolomics, to obtain detailed information about the chemical components of samples following microwave treatment, the primary metabolite profiles were determined using gas chromatography-mass spectrometry (GC-MS), and phytosterol compounds were detected through GC-flame ionization detector (FID) analysis. Mass spectral libraries were used to identify the primary metabolites and phytosterol compounds were confirmed by comparing the retention times of the standards. To better understand the biological functions of primary metabolites in various metabolic pathways, KEGG pathway analysis was performed. In lipidomics, GC-FID system was employed to investigate the effect of microwave treatment on the fatty acid compositions of the samples. The detected compounds were confirmed by comparing them with the retention times of the FAME standard. The nutritional quality of the composition in the samples was assessed by determining the ratio of unsaturated fatty acids (UFA) to saturated fatty acids (SFA). Hierarchical Cluster Analysis (HCA) and Principal Component Analysis (PCA) were conducted to interpret and compare data sets obtained through GC techniques.
The findings are important as they provide a foundation for a risk assessment approach regarding the food composition of microwave-treated GM food products using omics technologies, thereby supporting comprehensive studies to be undertaken by researchers and regulatory systems.
