Canning of foods first occurred in the 18th century but in jars! Due to the demands of long sea voyages, armies being away from home for long periods and the increasing needs of urban populations, effective means of food preservation were required. At the time, methods of preservation included drying, smoking, pickling and salting of foods, but were inadequate for preserving foods for a long period of time.
Canning is a method of preserving food in air-tight vacuum-sealed containers and heat processing sufficiently to enable storing the food at normal-home temperatures. Canning is one of the safest ways to preserve foods. To retain peak quality, the shelf life of canned food is at least two years, and the vitamin level in canned food remains stable during the shelf life as long as the container is not damaged in any way.
Canning has no effect on proteins, carbohydrates and fats. If you take can meat, for example, it will have the same amount of protein and fat after canning as it had before. In general, canning does not seem to affect the nutritional values of food very much. From that point of view, you don’t have to feel sorry about turning to a can for a quick and convenient meal. Your fresh vegetables can lose more vitamins by lying in storage rack for a week. Canning is a useful way to preserve vitamins, as concentrations of some vitamins can decrease by 50% within the first 7 days after harvest when stored at ambient temperatures.
Canned food only needs to be warmed through before serving because it has already been cooked in the can. By keeping the cooking juices, canned foods lose remarkably little of their nutritional value. Canned poultry and fish, both protein foods, are comparable to their fresh-cooked counterparts in nutritional value. Protein is not lost during the canning process. And some varieties of canned fish tend to have higher calcium levels than their freshly cooked counterparts.
Many canned fruits and vegetables are high in vitamin A; canned products have comparable levels of vitamin A to their fresh or frozen counterparts. Canned food retains vitamin C for up to two years because the can is completely sealed and the food inside is cooked and stored in a vacuum. Canned pineapple, asparagus and grapefruits are significant sources of vitamin C.
There are an enormous variety of canned foods, which differ both in terms of type of ingredients and method of processing. In the end, it can be clearly stated that it’s better to go for canned food rather than bad food.