Raspberries are an important commercial fruit crop, widely grown in all temperate regions of the world. The raspberry is the edible fruit of a multitude of plant species in the genus
Rubus. Red and black raspberries are canned by the same methods.
Raspberries should be picked when they are ripe but firm. The raspberries are then conveyed to the factory in crates of the shallow boxes to prevent bruising or crushing of the fruit.
Raspberries, like most berries, require considerable hand labor in preparing for canning. Berries are washed and sorted to remove the deformed and overripe berries unfit for canning. Raspberries are size graded using slat riddled.
The berries are placed in cans as they are washed, the filled can inverted to drain off the excess water, and the cans generally placed on a belt or some other type of filled can conveyor to carry them to the syruper.
The berries are canned in heavy syrup (50°-55° Brix) for dessert purpose, or in water for use in pies. If syrup is used, it should be added at a temperatue of at least 93 ° C. Some canners believe that the use of syrup that is too hot causes shrinkage of the berries.
Cans are exhausted until a center temperature of 18 °C is reached. This requires approximately 5-6 min at 100 °C.
Canning process of raspberries
