Determination of polyphenol oxidase enzyme activity of black mulberries (Morus nigra) grown in Igdır ecological conditions

In this study, places of white and black mulberry trees in Iğdır district and the villages (Melekli, Karakoyunlu) nearby were determined and the mulberries were collected twice yearly in June and July months of the years 2015 and 2016 in order to measure polyphenol oxidase enzyme (PFO) activities of these mulberries. However, no enzyme activity was detected in white mulberries. Therefore, the study was conducted with black mulberries. The mulberries collected were frozen at -20 °C. A crude enzyme extract making solution (Sodium acetate buffer containing % 1 polyethylene glycol (PEG) at pH (5,0) was prepared. 20 gr samples of the frozen berries were prepared using a precision scale and smashed in a mortar. 40 ml of the crude enzyme extract making solution was mixed with each mulberry genotype. The obtained mixtures were filtrated separately with four-folded cheesecloth, afterwards centrifuged for 30 minutes at 4 °C and 10.000 rpm. The supernatants were used as enzyme solutions. Enzyme activity of each solution was detected with a spectrophotometer. When descriptive statistics of each main effect were examined, it was observed that Melekli mulberries (ME1>ME2>ME3) had more enzyme activity. Nevertheless, the lowest enzyme activity was obtained from genotype K1. It was determined to be more enzyme activity in June month and the year 2015 compared with those in the year 2016 and July month. Keywords: Black mulberry (Morus nigra), polyphenol oxidase enzyme, Iğdır