Viscosity of Concentrated Red Grape Juice and Separation of Tartar

摘要

Wiping tartar is a quite important sector in grape juice producing and general methods include freezing processing, ion exchange processing, adding meta-tartaric acid, and so on. The combination of concentration and low temperature processing can get a satisfied result in dealing with the tartar of grape juice: because the solubility of tartar relies on temperature------the lower the temperature, the less the solubility, reducing the temperature of grape juice will result in the precipitation of hydrogen potassium tartrate and calcium tartrate (i. e. tartar) to the bottom of the container, by separating the precipitation can we wipe out the tartar from the juice. The experiment showed that the 70°Bx grape juice crystallized easier at 25℃ than at 4℃ and the key factor of this phenomenon was that the viscosity of high concentration grape juice at low temperature restrained the growing of tartar crystal. The experiment measured the viscosity change of grape juice with different sugar content at different temperature, and found the relationship between concentrated grape juice and tartar separation.