Preliminary evaluation of the effect of pH and temperature on polyphenoloxidase activity in yellow potato (Solanum phureja)

Abstract

Polyphenoloxidase (PFO) is an enzyme that catalyzes oxidation reactions, and as a result generates dark-brown tones that, in the transformation, processing, and post-harvest preservation of fruits and vegetables, are undesirable. This fact highlights the importance of knowing the activity of this enzyme in fruit and vegetable products. In the particular case of the yellow potato, today there is no methodology in Colombia and internationally, that makes explicit the evaluation of the PFO enzyme, so the objective of the present study was to evaluate the effect of the pH used in the reaction buffer, as well as that of two temperatures, on the activity of this enzyme. To do this, we worked with phosphate buffer solutions pH 5.5, 6.0 and 6.5 and temperatures of 20 and 25ºC, using unpurified extract obtained from yellow potato. The determination was carried out by spectrophotometry at 410 nm. The previous results obtained indicate that when using phosphate buffer at pH 6.5 tempered to 20ºC, the polyphenoloxidase enzyme develops a greater activity in the yellow potato.