Freeze concentration of must in a pilot plant falling film cryoconcentrator.

摘要

The standard methods of producing concentrated grape must are vacuum evaporation and reverse osmosis. Concentration by freezing is the system that comes closest to the ideal objective of separating water from the food product without affecting the other components. This article examines the process for freeze concentration of white must from Macabeo variety grapes. The pilot plant equipment designed at the Technical University of Catalonia is based on freezing the water content of fluids in direct contact with a cold surface. Different parameters were studied to allow tracking of the process: evolution of soluble solids and the ice production. Freeze concentration tests with forty five litters of must were made at an initial concentration of 16.4 degrees Brix. A final concentration of 29.5 degrees Brix was obtained. An average rate of 1.38 degrees Brix/h was obtained working at flow rates of 0.8 L/s. The ice production ranged from 1.32 to 1.05g g.m-2 .s-1 as the concentration of the must increased. Industrial relevance: Sometimes the must has low contents in sugars. The freeze concentration can achieve the appropriate level of concentration in some favorable conditions without losses of aroma and sensorial properties. With this purpose INCAVI (Catalonian Institute of vineyard and wine) provided 100 L of grape juice for the test presented in this article. In this work has been applied this technology to concentrate must (grape juice) obtaining promising results