Aug. 2014 to present: Professor of Food Chemistry at Biochemistry Department, Faculty of Agriculture, Zagazig University, Egypt.

Jan. 2013 to present (sabbatical leave): Professor of Biochemistry, Deanship of Scientific Research, Umm Al-Qura University, Makkah, KSA.

Nov. 2012: Visiting Professor (100% teaching) at School of Biomedicine, Far Eastern Federal University, Vladivostok, Russia.

Mar. 2009–June. 2014: Associate professor at Biochemistry Department, Faculty of Agriculture, Zagazig University, Egypt.

Mar. 2004–Aug. 2009: Assistant professor (University lecturer) at Biochemistry Department, Faculty of Agriculture, Zagazig University, Egypt.

Jan. 2010–Dec. 2010: Visiting Professor (100% research) at Faculty of Food and Agriculture, King Saud University, Kingdom of Saudi Arabia.

Oct. 2011- Dec. 2011 Post-doctoral fellow, Department of Nutrition and Food Science, College of Agriculture and Natural Resources, University of Maryland, MD, USA.

Feb. 2011- May 2011 Post-doctoral fellow (DAAD), Max Rubner Institute, German Federal Research Institute for Nutrition and Food, Department for Lipid Research, Detmold, Germany.

Nov. 2008- Nov. 2009 Post-doctoral fellow (Arab Distinguished Fellow), Institute of Food Chemistry, Technical University of Berlin, Germany.

Aug. 2007- Feb. 2008 Post-doctoral fellow (Parown-Egypt), Applied Chemistry and Microbiology Department, Faculty of Agriculture, University of Helsinki, Finland.

Jul. 2006- Oct. 2006 Post-doctoral fellow (DAAD), Institute of Food Chemistry and Technology, Technical University of Berlin, Germany.

Nov. 1998-Mar. 2004: Assistant lecturer at Agricultural Biochemistry Department, Faculty of Agriculture, Zagazig University, Egypt.

Dec. 1995-Nov. 1998: Demonstrator (Teaching Assistant) at Agricultural Biochemistry Department, Faculty of Agriculture, Zagazig University, Egypt.