Antioxidative effect of Maillard reaction products of spermine–sugar system on partially purified plum polyphenol oxidase

Abstract

One economic issue that arises from the procedures used to produce dyes from naturally occurring phenolic chemicals that enzymes have oxidized is called "enzymatic browning". Polyphenol oxidase's existence in most fruits and vegetables is in charge of this problem. Adding antioxidants is one of the most crucial strategies for halting this process. We used spectrophotometry to examine the antioxidant effects of Maillard reaction products on this enzyme. Five hours of heating at 100 °C was used to study the properties and antioxidant activity of model systems including spermine and monosaccharides (glucose, fructose, and ribose). Vitamin C was used as a control to compare the DPPH radical scavenging activity of the MRP spermine-sugar model systems. Intermediate products at A294 and a browning intensity at A420 nm were increased with heating time. This increase was associated with a decrease in reduced sugar and free amino group contents. Polyphenol oxidase from Mirabelle plum (Prunus domestica subsp. syriaca) was fractionated by ammonium sulfate precipitation, dialysis, and ion exchange chromatography. A single peak was obtained with specific activity 11292.6 U/mg protein. The MRPs exhibited inhibitory effects on purified Mirabelle plum PPO from (42.6- 70.2%) compared with vitamin C which was 57.9%. Furthermore, the Lineweaver-Burk plots discovered the inhibition modes noncompetitive by the strongest system, spermine-glucose.