Canning involves
heating food in a closed container to ensure that the micro-organisms
present in the raw food can no longer cause deterioration of the food
or be hazardous to health. The amount of the heating depends on the
type of food. Nutrient losses occur from destruction during heating
and storage stages. Some nutrients, such as water-soluble vitamins
and minerals, may dissolve in the water in the can, but they are lost
only if this liquid is not consumed. We can reduce losses of vitamins
during storage by storing the cans in a cool place.
Nutrient losses
resulting from canning are generally greater than those for the same
food when prepared from the fresh state in the home. However, this
must be balanced against the convenience of having foods available
at all times of the year no matter where we live or what the season.