Polyphenol Oxidase Enzyme Activity of Mulberries Grown in Iğdir Ecological Conditions

Abstract

The presence of polyphenol oxidase enzyme (PFO) in black and white mulberry varieties grown in Iğdır province were determined. In the study, no polyphenol oxidase enzyme was detected in the white mulberry varietie, therefore the study was conducted only with black mulberry varieties. The mulberry samples were collected from Iğdır Center, Melekli and Karakoyunlu districts during June and July, both in 2015 and 2016, when the fruits were fully ripe. Mulberries were stored at -20 °C, and the crude enzyme extract was stabilized with pH 5.0 sodium-acetate buffer containing 1% Polyethylene glycol (PEG). To weigh with a precision scale, 20 grams of frozen mulberries were taken into mortars. After the mulberries were thoroughly crushed in these mortars, 40 ml of crude enzyme extract preparation solution was added to each variety and mixed homogeneously. These mixtures were filtered through a cheesecloth and rotated at 4 °C, 10,000 rpm for 30 minutes. The obtained supernatants were used for enzyme solubilization, and the enzyme activity of the solution was determined spectrophotometrically. The PFO content depended on the genotype. There was a significant difference among the tested mulberry genotypes.