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Polysaccharide based clarification agents are more effective at removing tannins and maintaining anthocyanin content in pomegranate juice

7 May 2015

Researchers at the University of Ankara, Turkey have published the results of a study exploring the effects of natural sedimentation and clarification agents (albumin, casein, gelatin, chitosan and xanthan gum on total phenolics, hydrolysable tannins, anthocyanins and antioxidant activity) of pomegranate juice.  

When clarifying pomegranate juice, one aim is to reduce hydrolysable tannins, which are the main phenolic group which pass from the rind into the juice during the pressing of the fruit.  They are also responsible for any bitter taste in the juice. The removal of these tannins produces a clearer juice, which is more desirable to consumers. Protein based clarification agents, such as albumin and gelatin, have been found to remove hydrolysable tannins in, however they also remove the anthocyanins which are responsible for the red colouration. In order to maintain colour, the use of polysaccharide based-clarification agents was explored. 

In the study performed by Dr. Erkan-Koç, it was found that polysaccharide-based agents such as chitosan and xanthan gum could be used for effective hydrolysable tannin removal and maintenance of anthocyanin content in pomegranate juice, as well as delivering a high antioxidant activity (27% higher). Chitosan is however favoured as it resulted in halved turbidity compared to xantham gum.

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