To blanch or not to blanch? Freezing does not

To blanch or not to blanch?

Freezing does not destroy any of the microorganisms which cause changes in food quality and food safety. Bacterial growth is very slow at freezer temperatures so food is not apt to spoil in the freezer. There may be loss of quality, however. Changes in the color, flavor, and texture of fruits and vegetables can be caused by the enzymes which are responsible for ripening.

Heating foods before freezing will destroy the enzymes. That’s why blanching or steaming of vegetables is recommended. Heating does reduce the number of bacteria, yeasts, and molds present but its principal purpose is to destroy enzymes. Heating also makes vegetables easier to pack into containers.

To blanch, lower a small amount of vegetable into boiling water. The ratio of vegetable to water should be such that the water doesn’t stop boiling. A pound of prepared vegetable to a gallon of water is a common proportion. The blanching time must be long enough for heat to penetrate the food. As a rule, the larger the piece, the longer the blanching time. Thus the extremes go from IV2 minutes for green peas to 11 minutes for large ears of com. Start counting blanching time when food is immersed in boiling water.

Enzyme action may be stopped by steaming foods rather than boiling them. The time required for heat penetration is greater for steaming than for blanching. Whether blanched, steamed, or par-cooked, it is important to cook the vegetable quickly to stop the cooking process. Plunge the vegetable into ice cold water for about the same length of time you heated it. Then drain, package, and freeze. For some foods, you may find it more satisfactory to set the containers of food in ice water for cooling.

Remember, enyzmes affect food quality, not food safety. If food is used in a short time or heavily seasoned, changes in quality may not be detected.