Inhibitory effects of α-Na8SiW11CoO40 on tyrosinase and its application in controlling browning of fresh-cut apples

Visual appearance of fresh-cut apples with (a) or without (b) short-term SiW11Co treatment after 2 h. α-Na8SiW11CoO40 (SiW11Co) was synthesized and characterized. The Native-PAGE and the spectrophotometry assay showed that SiW11Co had a significant inhibitory effect on tyrosinase dose-dependently (IC50 = 0.239 mM, KI = 0.164 mM). In addition, the assay on the browning of apple slices indicated that SiW11Co treatment could significantly decrease the browning degree of apples slices and the activity of polyphenol oxidase (PPO), and controlled the oxidation of fresh-cut fruits and vegetables. As shown in figure, visual appearance of apple slices in treatment group was apparently lighter than that of the control group, which also suggested that SiW11Co could inhibit the browning process of apple slices distinctly.195