Rhubarb Juice as a Natural Antibrowning Agent

To search for natural antibrowning agents, rhubarb juice was tested on fresh‐cut apple slices and found to have a potent effect. Liberty apple slices were treated in various concentrations of rhubarb juice (5%–100%), and the rate of discoloration at room temperature was measured by a Hunter Colorimeter. Apple slices treated in the 5%– 10% solution showed browning activity with dL values of 2.3 – 2.5 at two hours. However, the concentrations of rhubarb juice above 20% inhibited apple browning effectively with no change in the L value for several hours. Analysis of oxalic acid in rhubarb juice showed that the 20% solution contained about 67 mg/100g.