1 3 Eur Food Res Technol DOI 10.1007/s00217-014-2246-4 ORIGINAL PAPER Impact of fruit processing methods on DNA extraction from transgenic frozen banana products Farzaneh Abdolmaleki · Mahnaz Mazaheri Assadi · Hamid Ezzatpanah · Masoud Honarvar Received: 19 October 2013 / Revised: 28 April 2014 / Accepted: 5 May 2014 © Springer-Verlag Berlin Heidelberg 2014 Introduction Genetically modified organisms (GMOs) as food and in food products are being used more and more prevalently. Although GMOs have progressed considerably, consumers have provided some negative feedback [1, 2]. This has led many countries to establish rules and regulations in order to label each product as either being a GMO or containing a genetically modified ingredient [3, 4]. The GM banana is the initiate staple fruit in Uganda developed through modern biotechnology. Several trans- genic traits are being developed such as resistant to the air- borne fungal black leaf spot disease, or “black Sigatoka” (Mycosphaerella fijiensis), and a nutritional enhancement characteristic (enhanced carotenoid content). The bananas selected for modification are local cooking bananas, due to the extensive grow and high preference by consum- ers [5]. East African highland cooking bananas are mostly produced and consumed locally, with little regional trade and trifling exports. Furthermore, GM bananas have a real potential for making a difference in smallholders’ welfare as a source of food and/or income [6]. Although, Smale and De Groote [7] noted the potential risks of GM banana such as gene flow, resistance evolution in targeted pest popula- tions (due to genetic uniformity), health, and nontarget species effects. The researchers confirm the existence of limited scientific evidence on the different impacts of GM banana. A new detection method has recently been developed to quantify GMOs and implementation of labeling regula- tions based on quantitative real-time PCR [8]. This method estimates the amount of targets available and hence any impact on DNA degradation was seen during the process- ing. The measured mean DNA copy number ratios of the processed samples were in consistence with the expected Abstract Isolation of high yield and quality of genomic DNA is paramount for ensuring confidence in molecular analyzing food. This study evaluated five different DNA extraction procedures based on laboratory protocols and commercial kits for their efficiency and also assessed the impact of processing procedures on the DNA degradation in various frozen banana products such as frozen-sliced banana, frozen banana puree, frozen plantain banana, and freeze-dried banana powder. The purity and concentration of DNA obtained from the samples were evaluated by spectro- photometric and gel electrophoresis analysis. Of the various extraction procedures, we applied modified protocols that allow for effective extraction of DNA from banana. This protocol derived from traditional cetyltrimethylammonium bromide method with modifications that allowed removing unwanted polyphenols and polysaccharides. The results con- firm that a profound impact on DNA degradation was seen during the processing of banana products, DNA could still be reliably quantified by real-time PCR. Furthermore, fry- ing resulted in further degradations and drying resulted in the most severe changes. It was noted that in different frozen banana products, nopaline synthase fragment is most stable followed by cauliflower mosaic virus 35S and NPTII gene. Keywords DNA extraction · Frozen products · Freeze processing · Plantain banana F. Abdolmaleki (*) · H. Ezzatpanah · M. Honarvar Food Science and Technology Department, Faculty of Agriculture and Natural Resources, Science and Research Branch, Islamic Azad University, Tehran, Iran e-mail: fa.abdolmaleki@gmail.com M. M. Assadi Department of Biotechnology, Iranian Research Organization for Science and Technology (IROST), Tehran, Iran