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Application of advanced methodologies for the analysis of protein oxidation in muscle foods

Final Report Summary - POX-MEAT (Application of advanced methodologies for the analysis of protein oxidation in muscle foods)

The present project was planned to provide insight into the chemistry behind the oxidative damage to proteins in meat and meat products through the analysis of novel oxidation markers and the application of advanced methodologies. As an reintegration Marie Curie fellowship (ERG-POX-MEAT; 2010 - 2013), the grant was intended to facilitate the consolidation of the fellow (also scientists-in-charge of the present project) in his home university (University of Extremadura, Spain) upon the completion of a postdoctoral stay at the University of Helsinki (Finland) supported by a previous intra-European Marie Curie fellowship (IEF-POX-MUSCLE; 2007 - 2009). As a straightforward continuation of the previous Marie Curie fellowship, this project was successfully implemented by using the skills and knowledge gained during the postdoctoral training in Helsinki. The present project was implemented in parallel with another competitive project with shared objectives funded by the Spanish Ministry of Economy and Competitiveness (AGL2010-15134) and contracts with various enterprises and food companies. The achievements of this project include:

i) a prolific and relevant scientific and technological contribution;
ii) advanced training of PhD students and postdoctoral researchers (under the supervision of the fellow);
iii) reinforcement of existing research networks between the fellow’s group and other groups in Europe and the world; and
iv) the consolidation of the fellow as an independent and mature researcher in the current institution.

All these aspects will be covered in brief.

Protein oxidation (POX) is a hot topic in medical research owing to the connection between the oxidative damage to proteins in living tissues and aging and disease (Stadtman, 2001; DOI: 10.1111/j.1749-6632.2001.tb05632.x). Until recently, this topic was scarcely studied in food science as lipid oxidation concentrated for decades all the attention of food scientists. The progress in this field required the development of advanced and accurate methodologies to shed light on the chemistry behind POX. Only by having this chemistry background, the real scientific and technological significance of POX in food systems would be unveiled. During the previous Marie Curie fellowship, the fellow detected for the first time in food proteins particular protein carbonyls (aminiadipic and glumatic semialdehydes, AAS and GGS, respectively) as markers of the oxidative damage caused by ROS (Estévez et al., 2009; DOI: 10.1021/jf804017p) and contributed a solid background on which more challenging studies could be developed. During the current project, the fellow has deepen into this chemistry background:

i) by detecting additional novel POX products (carbonyls, aminoadipic acid, Schiff bases) (DOI: 10.1016/j.meatsci.2011.05.017 DOI: 10.1021/jf3001313);
ii) by shedding light on the implication of these POX products in further reactions (DOI: 10.1016/j.foodchem.2011.04.012) and the interaction with lipid oxidation and the Maillard reaction (DOI: 10.1021/jf305451p; DOI: 10.1021/jf2040753; DOI: 10.1016/j.meatsci.2011.06.007); and
iii) by identifying the impact of these oxidative changes on the functionality of proteins (DOI: 10.1021/jf302111j) and on particular quality traits of muscle foods (DOI: 10.1111/j.1750-3841.2011.02327.x; DOI: 10.1021/jf104995j).

Additionally, the fellow has contributed to understand the interaction mechanisms between food proteins and phytochemicals (DOI: 10.1016/j.foodchem.2012.04.101) and consistently, has developed antioxidant strategies based on natural antioxidant to control oxidative reactions in food systems (DOI: 10.1016/j.meatsci.2012.05.010; DOI: 10.1016/j.meatsci.2011.04.013 DOI: 10.1021/jf1048832). Four of these strategies have been protected by corresponding patents (Application of extracts from rose-hips, strawberry tree, and avocado by-products with antioxidant properties in foods). Most of these studies have been focused on muscle-based foods, in line with the fellow's background and project objectives. The knowledge gained during these years has been transferred:

1) to the industry through contracts (Consorcio Jabugo S.A.) participation in workshops (see http://www.csisp.gva.es/documents/10157/8e1e2c0d-196b-42e1-9eed-4a408e6ee4e3 for details), technical papers (see http://www.eurocarne.com/index.php?/revista/fichas/ficha_revista?codigo=15886 & 15913 for details), and shared publications (DOI: 10.1016/j.meatsci.2012.06.005); and
2) to the academic world through participation in PhD courses (University of Extremadura and University of Lleida, Spain) and advanced international courses (ICoMST 2011, Gent, Belgium; ICoMST 2013, Izmir, Turkey).

In mid 2009, when the fellow (M. Estévez) made the application for the present ERG grant, he had published 36 papers in science citation indexed (SCI), peer-reviewed journals and had an H-index of 12. At the present moment, 3 years later, he has almost doubled the scientific production up to 65 and owns an H-index of 20. The results from the studies carried out under the funding coverage of the present fellowship have been published in 17 articles in peer-reviewed journals, 2 book chapters, several congress communications and technical papers.

These papers include the only two review papers on the topic covered by the present project: POX in muscle foods. One of these review papers (DOI: 10.1016/j.meatsci.2011.04.025) was made upon an invitation to participate as a key-note speaker in the International Congress of Meat Science and Technology in Gent (2011). The other review paper (DOI: 10.1002/mnfr.201000453) was promoted and submitted by the fellow, made in collaboration with colleagues from the Universities of Helsinki and Copenhagen and eventually published in the highest-cited Journal in Food Science and Technology (ranked No. 1 according to ISI web of knowledge 2010). Both articles include original data obtained from the present fellowship and are among the most cited and downloaded articles in their corresponding journals. Both articles are attached to this report as ultimate and distinct proof of the excellent work accomplished by the fellow to establish himself as a recognizable expert in his field.

These research studies have been accomplished in collaboration with PhD students and researchers from his own and other institutions, including international students / researchers from the Universities of Gent (Prof. DeSmet), Copenhagen (Dr Lund) and Helsinki (Prof. Heinonen) in Europe, the Research Institute ILVO (Belgium), the Technical Institute of Leiria (Portugal), the University of Nayarit (Mexico) and the University of Zagazig (Prof. Hassanien, Egypt). With the support from this project, the fellow has supervised one PhD Thesis (Dr Rodríguez-Carpena, Mexico) and is currently supervising another two (Ms Mariana Utrera, México and Ms Adriana Villaverde, Spain). Additionally, the fellow has supervised short stays of several national and international students including Dr Rui Ganhao (Portugal), Ms Els Vossen and Ms Tine Rysman (Belgium), Ms Iria Muiño (INIA, Spain), Mr Phillip Olugbenga (Lacombe, Canada) and Dr Adriana Pazos (INTA, Argentina).

The fellow of the present project has been able to establish himself as one of the main recognisable and most prolific experts in his field. As such, the fellow passed successfully the first step of the prestigious Starting Grant from the European Research Council (ERC) with a project about 'Advanced studies on food POX: From chemistry fundamentals to the impact on human nutrition' with which the fellow aspires to endure working on this fascinating topic. By the time this report was prepared (May 2013), the fellow was awaiting the final decision on this upcoming project. The fellow is leading a group of researchers working on POX at his home university (Extremadura), imparts regular lessons to Master and PhD students and is an active member of management and advisory panels of the Faculty of Veterinary at this university.