Titratable acidity (TA), pH, total soluble solids (TSS) and ascorbic acid. TA was analyzed according to the Assn. of Official Analytical Chemists (AOAC) 942.15 method and was expressed as g of citric acid per 100 g of sample. Measurements of pH were carried out with a pH-meter (Beckman model 390), according to the AOAC method 981.12. The TSS content was determined according to AOAC method 932.14 using a refractometer(ExtechmodelRF15),and results were expressed as°Brix (AOAC 1990). In addition, ascorbic acid was determined by titration with an iodine solution and expressed as ascorbic acid content in 100 g of sample. Each test was performed in triplicate.