The stem tips were removed and fruits immersed in chlorinated water (300 ppm) for 20 min. Fruits were either subjected to hand peeling, steam peeling or lye peeling. In steam peeling, the fruits were exposed to live steam at 100 °C for 6-8 min. Fruits were also soaked in either 5 or 10% lye solution for 30-60s at 28-3 °C.
The slicing operation is usually an integral part of the peeling and coring process where the apples are sliced into 12 to 16 pieces in the coring section. After slicing, the apples are inspected for defects such as blossom or calyx, carpel tissue, skin, and bruises and are conveyed over a shaker screen to remove small chips. Apple slice texture is very important. Therefore, apples with firm flesh and high quality are desired. Consistency of slice size can be controlled by using fruit from within a preselected size range.
Adding syrup to canned fruit helps retain its flavor, color and shape. It does not prevent spoilage of these foods. By using syrups offer a new “very light” syrup, which approximates the natural sugar content of many fruits.
In canning regular fruits without sugar, selecting fully ripe but firm fruits of the best quality is very important. Prepare these as for hot-packs but use water or regular unsweetened fruit juices instead of sugar syrup. Juice made from the fruit being canned is best. Blends of unsweetened apple, pineapple and white grape juice also are good for filling over solid fruit pieces.
The canned apples must be processed immediately after closing to a can center temperature of 82.2°C; there are several types of sterilizers available, Batch retort vessels, and continuous rotary cookers that operate either at atmospheric or pressurized conditions. Immediately after sterilizing, the cans should be cooled at 37 to 40°C to prevent “stack burn” or loss of product color in storage.
Canning of apple slices
