Effects of processing method and storage temperature on clear pomegranate juice turbidity and color
Clear pomegranate juice possesses a very attractive color and low turbidity that are affected by processing methods and storage temperatures. In this study, different extraction (pressing with fruit husk and pressing only with fruit arils), clarification (hot and cold) and filtration (via kieselguhr or active charcoal) techniques were compared to determine their effect on color and turbidity. All samples were stored at two different temperatures for 6 months. Cold clarification and low storage temperature (5C) produced pomegranate juice with minimum color loss (total color difference, ΔE = 1.45) and low turbidity (.91 NTU) even after 6 months of storage.PRACTICAL APPLICATIONSPomegranate juice is a favorite beverage with a high total phenolic content related to the management of many metabolic disorders. However, excessive concentrations of these valuable compounds cause visual problems in the juice that reduce its appeal to consumers. The procedures for producing clear pomegranate juice are very important. This study focused on the ability of different extraction, clarification and filtration techniques to produce clear juice and the effect of storage temperatures on the development of turbidity and color in the extracted juice. Although mainly hot clarification procedures are preferred in the commercial fruit juice industry, we found that cold clarification is minimized turbidity and color. Also, using active charcoal filtration and storage of the product at lower temperature and can help to maintain initial juice characteristics during the shelf life.
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