Effect of Different Concentration Techniques on Some Properties of Fresh and Stored Pomegranate Juice

摘要

Background and Objective: Pomegranate is a well-known fruit consumed as fresh or beverages and has chemo-prevention activities of various types of cancers. Pomegranate juice concentration was very important to keep its quality and the stability of sensory properties . The aim of this study was to evaluate different concentration techniques such as rotary evaporator, conventional direct heat and microwave on some properties of concentrated pomegranate juice and color stability. Materials and Methods: Total Soluble Solids (TSS), total phenols, anthocyanin contents and antioxidant activity of the fresh concentrated samples either fresh and during cold storage at (7±2°C) for 30 days were determined and statically analyzed using one way (ANOVA). Hunter instrument was used to measure colors changes in the juice and all concentrated samples. Results: The TSS of concentrated samples were 49.4, 49.5 and 51.6° Brix by using direct heat, microwave and rotary evaporator, respectively. Sample was concentrated by rotary evaporator had the highest value of the redness (a*) followed by microwave and direct heat compared with the juice sample. The rotary evaporator caused higher anthocyanin content (761.47 mg/100 mL) compared with other techniques. Prolong the cold storage increased moral content of phenols, anthocyanin and the antioxidant activity of all concentrated samples compared with the juice. Conclusion: It can be concluded that concentrated pomegranate juice by either microwave or rotary evaporator resulted in less degradation of total phenol and anthocyanin contents. Concentration of pomegranate juice by different techniques could be used to fortified several food products including dairy products.