Q: I am interested in freezing my garden produce and potentially some freezer meals, what do I need to know?
A: Freezing food is easy, convenient, and the least time-consuming food preservation method. But freezing food is a science because of the chemical and physical changes that occur over freezer storage time.
Freezing does not kill bacteria, it only slows down the growth of bacteria and slows the enzyme activity which can affect the quality of the food. Freezing will affect the texture of any food because the water in the food expands and breaks cell walls. This results in softer products, especially in fruit. Quality is also affected by fluctuating temperatures during freezer storage. Foods may thaw slightly, then refreeze and ice crystals form on the package. For best storage, keep the freezer below 0°F, this helps retain vitamin content, color, flavor and texture.
Freshness and quality at the time of freezing affect the condition of frozen foods. If frozen at peak quality, thawed foods emerge tasting better than foods frozen near the end of their useful life. The freezing process itself does not destroy nutrients. In meat and poultry products, there is little change in nutrient value during freezer storage.
Color changes can occur in frozen foods. The bright red color of meat as purchased usually turns dark or pale brown depending on its variety. This may be due to lack of oxygen, freezer burn or abnormally long storage. Freezing doesn’t usually cause color changes in poultry. However, the bones and the meat near them can become dark. The dulling of color in frozen vegetables and cooked foods is usually the result of excessive drying due to improper packaging or over-lengthy storage.
Enzyme activity does not harm frozen meats or fish and is neutralized by the acids in frozen fruits. But most vegetables that freeze well are low acid and require brief, partial cooking to prevent deterioration. This is called “blanching.” Blanching slows or stops the action of enzymes that can cause loss of flavor, color and texture. Blanching cleanses the surface of dirt and organisms, brightens the color and helps retard loss of vitamins. Blanching also wilts or softens vegetables and makes them easier to pack. Blanching time is crucial and varies with the vegetable and its size. Underblanching stimulates the activity of enzymes and is worse than no blanching. Overblanching causes loss of flavor, color, vitamins and minerals. Be sure to look up instructions on blanching times for all vegetables. More information can be found at: http://nchfp.uga.edu/publications/uga/uga_freeze_veg.pdf
