| 摘要 |
A method of concentrating fruits which preserves the original coloration and freshness of flavor and retains the structural integrity of the fruit for subsequent preserving or canning operations. The fruit is first subjected to a high vacuum while adding only enough heat to maintain the fruit at a temperature below the boiling temperature of water at the maintained vacuum. This is continued until foaming caused by the release of air in the cells of the fruit either ceases or is at least commencing to be reduced. The fruit is then moved in a thin layer through a heated, rotating cylinder maintained at the same vacuum to cause the juices in the fruit cells to migrate to the surface of the fruit. As the cylinder rotates, the juices coat the walls of the cylinder. The cylinder is heated to a temperature above the boiling point of water at the maintained vacuum to boil off this coating. The speed of rotation and the temperature are so interrelated that at least a major portion of the inner wall of the cylinder is continuously wetted by the coating of juices and the fruit is not tumbled in the cylinder. The process is continued until the desired degree of concentration has been reached. |
