*Front end operation
*Juice extraction
*Juice clarification and refining
*Juice pasteurization and concentration
Grapes at the plant are first conveyed to a steamer which remove residual stems, leaves and petiole from fruit. After cleaning, grapes are crushed to facilitate juice extraction during the pressing step.
The crusher consists of several ruffled rotary rollers that break the berries while they are passing through. In most commercial operations, the continuous pressing method is used. Hot pressing is appropriate for deeply pigmented grape where maximum color extraction is desired.
Whereas, the immediate or cold press procedure is necessary to maintain the initial color of light colored grapes.
Additional enzyme treatment is required before the juiced is further processed For concentration it is necessary to complete the de-pectinization process to preclude gelation of the concentrate once produced.
For bottled juice, de-pectinization speeds and simplifies polish filtration and clarification prior to bottling.
Juice may be concentrated by evaporation or freeze concentration. It is desirable to heat the juice for as short a time as possible and to rapidly cook the product in order to minimize the effect on flavor, aroma and sugar concentration.
Manufacturing of grape juice
