|Freezing & Pickling|
Freezing has many advantages over other methods of food preservation. Frozen foods are often more like fresh, because they often retain their color, flavor and nutritive value. Freezing is also one of the easiest, less labor-intensive food-preservation methods.
Foods naturally contain enzymes which cause chemical changes which lead to deterioration. In most cases, prior to freezing, vegetables are blanched and fruits are treated to retard enzyme activity.
When freezing most vegetables, you generally want to heat-treat them for a short period of time to reduce the enzyme activity. This process is called blanching. Blanching is placing the vegetables into rapidly boiling water, or sometimes steam, for a short period of time. This step stops or slows down the enzymes causing undesirable changes. Refer to a reliable freezing reference for recommended blanching times for particular vegetable.
After blanching, it is recommended to immediately immerse the vegetables in ice water to stop the cooking process. Blanching is not intended to cook the vegetables, simply to inactivate the enzyme activity. You generally chill the foods for the same amount of time as recommended for blanching. Now drain and I prefer to dry the foods before packing. Draining/drying reduces the formation of ice crystals which will affect the quality of the product. Finally, place the cooled, dried vegetable in an air-tight, vapor-resistant container designed for freezing. Remove as much air as possible from the container. Label and store in a freezer, 0 degrees or colder.
Some prefer to completely cook certain vegetables before freezing, which is also acceptable. A couple of vegetables often prepared this way are cream-style corn and greens. After cooking the food to the desired doneness, they also need to be cooled before freezing. These foods are generally placed in a large bowl or pot set in ice water and stirred until the food is cool.
Blanching softens the texture of fruits, so controlling enzyme activity in fruits is best accomplished by adding sugar and antioxidants. Darkening of fruit is caused by oxidation, when the fruit is exposed to air. Ascorbic acid, vitamin C, citric acid or sugar syrup helps to prevent discoloration. Steaming fruit just until hot before packing will also control darkening. Steaming works best for fruit that will be cooked before use.
Three methods are generally used to pack fruit for freezing: syrup pack, sugar pack and unsweetened pack. The syrup or sugar pack helps the fruit retain better texture, color and flavor. But, for those watching their weight or needing to limit their sugar consumption, dry pack is acceptable.
Some foods like berries and chopped onions and peppers are especially easy to freeze. After rinsing and drying, spread on a cookie sheet and freeze. Then quickly place in a freezer container, remove as much air from the container as possible and return to the freezer. By freezing this way, the desired portion is easily removed, and the rest can remain frozen for future use.
Freezer bags, rigid plastic containers and freezer jars are all suitable for freezing. Freezer bags are better suited for dry packed foods, while rigid containers and glass are especially recommended for liquid packs, but also suitable for dry packs. If you use glass containers, make sure the jars are designed for freezing.
Keep these following tips in mind when freezing:
Pickling and Water Bath Canning
When people think of pickles, cucumber usually come to mind. But cucumbers are just one of many fruits and vegetables that can be preserved by pickling. Some other favorites are pickled like green tomatoes, okra, peppers, squash, onions, watermelon rind, beets, sauerkraut, relishes and peaches.
There are basically two categories of pickles:
If you are planning pickling produce this summer, keep in mind the following tips:
· For best quality, choose fruits and vegetables that are firm, but ripe and in good condition. Pickle your produce within 24 hours of harvest, the sooner the better.
· Remove the blossom end of cucumbers. The blossom end contains enzymes causing excessive softening of the final product.
· For a crisper pickle instead of using alum soak the cucumbers whole or sliced in ice water for a couple of hours before you pickle and then preserve them
· The vinegar used can be white or cider, of at least 5% acidity. Never decrease or dilute the amount of vinegar in a recipe because the preservative affect will be altered.
· Canning or pickling salt is best for pickling because they do not contain iodine. Iodine causes darkening. If you use reduced-sodium salt, use only for fresh-pack pickles – never for fermented or brined pickles. Fresh-pack pickles are acidified with vinegar, so they can be prepared with less or no salt. However, their flavor and texture will be affected.
· Spices used in pickles should be fresh, whole spices. Powdered spices cause darkening and a cloudy brine. If good-quality ingredients and up-to-date methods are followed, lime and alum are not needed for crispy pickles.
· Pickling solutions should be heated in unchipped enamelware, stainless steel, aluminum or glass. Never use copper, brass, galvanized or iron cookware or utensils. These metals can react with acids or salts and cause color changes in the pickles or form undesired compounds.
· Pickled products need to be processed in a boiling water bath canner to sterilize the head space and to insure a tight seal, but special precautions need to be taken so the pickles don’t cook and become mushy.
Angela Treadaway is a Regional Extension Agent in Food Safety. For any questions on food safety or preparation of vegetables, contact her at (205) 410-3696 or your local county Extension office.