A simple and effective procedure was developed to extract pectin methylesterase (PME) from Valencia orange peels. Orange peels contain 25-34 μmol of COOH min−1 g−1 of peel PME activity. The enzyme was ionically bound to cell walls and could not be extracted with water. | Research Article Turk J Agric For 34 (2010) 109-119 © TÜBİTAK doi: Commercially suitable pectin methylesterase from Valencia orange peels Şebnem ŞİMŞEK1, Ahmet YEMENİCİOĞLU2,* 1Department of Food Engineering, Faculty of Engineering, Ege University, 35100 Bornova, İzmir - TURKEY 2Department of Food Engineering, Faculty of Engineering, İzmir Institute of Technology, 35430 Gülbahçe Köyü, Urla, İzmir - TURKEY Received: Abstract: A simple and effective procedure was developed to extract pectin methylesterase (PME) from Valencia orange −1 −1 peels. Orange peels contain 25-34 μmol of COOH min g of peel PME activity. The enzyme was ionically bound to cell walls and could not be extracted with water. This enables removal of water soluble pectic substances and oils from peels via homogenization and washing with water before enzyme extraction. Enzyme extraction can be conducted simply by −1 addition of suitable amounts of NaCl (optimum: 10 g of NaCl 100 g of extraction mixture) to peel homogenate and stirring (optimum: 30 min at 200 rpm). The PME extracted from orange peels contains almost the same amount of heatstable and heat-labile fraction, and the enzymes cannot be activated by mild heating. A slight activation of enzyme (almost 20%) was achieved by adding 1 mM CaCl2 to enzyme extracts, but this agent was inhibitory at higher concentrations. The extracts stabilized by Na-benzoate and K-sorbate maintained more than 90% of their PME activity at 4 °C for at least 5 months. The obtained PME was successfully used to prepare low-methoxyl citrus pectin used in edible film formation in the presence of CaCl2. This study shows the potential of using Valencia orange peels as a source of commercial PME. Key words: Extraction, orange peel, pectin methylesterase, stability, Valencia orange Valencia portakal kabuklarından ticari olabilecek pektin metilesteraz eldesi Özet: Bu çalışmada pektin metilesteraz (PME) enziminin Valencia portakal .
