Comparison of Physicochemical Properties and Physiological Activities of Commercial Fruit Juices
In this study, the physicochemical and physiological activities of 10 different commercially available juices (apple juice-A: cloud type; apple juice-B: clear type; blueberry juice; grape juice-A; grape juice-B; orange juice-A; orange juice-B; pineapple juice; pomegranate juice; and tomato juice) were investigated. The average pH, titratable acidity, Brix, and reducing sugar were 3.57, 0.57%, 13.1 ˚Brix, and 57.58%, respectively. The total polyphenol and flavonoid contents were within the ranges of 98.29-878.12 ug/mL and 23.82-156.63 ug/mL, respectively, and pomegranate juice showed the highest content, followed by blueberry juice and apple juice-A. In the DPPH radical scavenging assay, apple juice-A, grape juice-A, and pomegranate juice exhibited the highest activity (greater than 90%) while orange juice-B, pineapple juice and tomato juice showed the weakest. The tyrosinase inhibitory effect was highest in apple juice-A, followed by orange juice-A and blueberry juice. The reducing power was highest in pomegranate
juice and lowest in pineapple juice and grape juice-A. The antioxidant activity by reducing power was highly correlated with the total polyphenol content.