Tips to safely can and freeze fruits and vegetables
STILLWATER, Okla. – Gardeners from around the state are enjoying the fruits of their labor as they consume the various fruits and vegetables they have grown in their gardens or on their fruit trees. Those who do not garden have probably found a bounty of offerings at their local farmers markets.
What do you do when you have an overabundance of fresh fruits and vegetables? Depending on the type of produce, you have the option of canning or freezing to help preserve this bounty, said Barbara Brown, Oklahoma State University Cooperative Extension food specialist.
“Canning and freezing both are excellent ways to prolong the freshness of just-picked fruits and vegetables. If done correctly, you can savor the flavor all year long,” Brown said.
Blanch vegetables before freezing them. This is the process of heating or scalding vegetables in boiling water or steam for a short amount of time to slow or stop enzymatic action that reduces flavor, color and texture.
In addition, blanching removes dirt and organisms from the surface of vegetables and helps slow down vitamin loss. It also softens vegetables, making them easier to pack in freezer containers.
Blanching time is crucial and varies with the vegetable and size. Underblanching stimulates the activity of enzymes and is worse than no blanching. Overblanching causes loss of flavor, color, vitamins and minerals.
Blanching times for vegetables commonly grown in Oklahoma can be found on the website for the National Center for Home Food Preservation at http://www.uga.edu/nchfp/index.html. Water blanching is the most common method for blanching home frozen vegetables. Tools needed include a wire blanching basket and a large kettle with a fitted lid.
Use one gallon of boiling water for each pound of prepared vegetables. Place the vegetables in the wire basket, lower it into the boiling water and begin blanching time as soon as the water returns to a boil, usually within one minute. Brown said if the water takes longer than one minute to return to a boil you are using too many vegetables for the amount of water.
“Once you’ve blanched the vegetables, quickly and thoroughly cool them to stop the cooking process. To cool, plunge the basket of vegetables immediately into a large quantity of cold water, 60 F or below,” she said. “Change the water frequently or use cold running water or ice water. If ice is used, about one pound of ice for each pound of vegetable is needed. Cooling vegetables should take the same amount of time as blanching. Overcooked vegetables lose flavor, color, vitamins and minerals.”
Make sure to completely drain the vegetables as well. Inadequate draining before freezing, slow freezing or temperature fluctuations above zero also can affect the quality, texture and appearance of your vegetables.
Brown said it is important to start with high quality fresh food at optimum maturity and freshness because frozen food is only as good at the quality with which you start.
“Keep in mind that freezing doesn’t kill all bacteria, yeasts and molds in food, but it does keep them from rapidly multiplying when food remains at zero or less,” she said. “However, surviving organisms can multiply when foods are thawed.”
When canning foods always follow directions from a reliable source dated 1988 or later and be careful not to over pack jars as this can cause inadequate processing and result in unsafe food. Vegetables must be processed in a pressure canner for the required USDA processing time unless they are pickled according to a tested recipe and process schedule. Pickled foods such as cucumber pickles or pickled okra can be safely processed in a boiling water canner when directions are carefully followed.
One step that is important for safety when pressure canning, but sometimes skipped, is to allow steam to escape for 10 minutes before closing the valve or putting the weight on the vent of the pressure cooker. This allows the inside temperature to correspond to that of the pressure gauge.
If you discover an unsealed jar within 24 hours after canning, the food can safely be re-canned but the quality will be lowered. Remove the lid to check the rim of the jar for any nicks and change the jar if needed. Add a new, treated lid and reprocess using the original processing time.
“Properly canned food will retain optimum eating quality several months when stored in a cool, dry place,” Brown said.
Oklahoma State University, U.S. Department of Agriculture, State and Local Governments Cooperating: The Oklahoma Cooperative Extension Service offers its programs to all eligible persons regardless of race, color, national origin, religion, gender, age, disability, or status as a veteran, and is an equal opportunity employer.
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