Orange juice concentrate is one of the most important orange products, which is widely appreciated in the world market. Concentration of orange juice by evaporation alters the final color, taste, aroma and nutritional characteristics of reconstituted juice. Therefore, the present study was carried out to evaluate the following points: 1. Evaluation of the use of enzymatic treatment in combination with serum pulp method for concentration of Valencia orange juice and the impact of this process on chemical composition and volatile flavor compounds. 2. The effect of pasteurization on the physicochemical properties and volatile flavor compounds of Valencia orange juice, pulp and serum. Both unpasteurized orange juice and serum separated from it was concentrated by a rotary evaporator under vacuum.