Today, the juice is a commercial product with a high nutritional value consumed by many of people. This growing interest causes juice producers are trying to create variety in the production of this product. Barberry juice is a tasty drink which is used by the Iranian people, especially during the summer for purification of blood. This juice contains organic acids(malic acid and tartaric acid), phenolic compounds, anthocyanins and carotenoids. Today, with respect to the benefits of production of juice concentrate for beverage factories, one of the priorities of the factories is the production of high quality concentrate. In this study, barberry juice concentrate with about brix 60 was produced by using an electromagnetic hot plate at atmospheric pressure, a 320 W microwave oven and at atmospheric pressure and, a 320 W microwave- vacuum oven and at pressure 30 KPa.The biochemical properties were measured during the concentration. The results showed that lesser time is needed for preparing concentrate by using vacuum- microwave oven. Also during concentration, antioxidant activity, anthocyanin content, phenolic content and color index(L,a,b) decreased but this reduction in microwave- vacuum system was lesser than other concentration method(P 0.05). Also the color difference index(?E) increased in compared to the initial content of index in the concentrate. Also in vacuum- microwave system,increasing this index was lesser than other methods due to reduce oxygen and preventing oxidation. Therefore, color of the concentrate protected better. By measuring of boiling point of the samples observed that the boiling point of the obtained juice from microwave oven in atmospheric pressure is higher than the boiling point of the obtained juice from electromagnetic hot plate and vacuum-microwave system. According the results microwave-vacuum system because of reduce oxygen and preventing oxidation, increased quality of product in addition to decreasing time of concentration. Consequently, this method can used for the production of high quality product. Keywords: Barberry juice, Concentrate, Microwave, Microwave-vacuum
