Cedar Creek Voice

[Article from Grand Traverse Herald newspaper, 8/19/08.]

FREEZING YOUR SUMMER PRODUCE

by Beth Waitrovich

Bountiful summer harvests can result in tasty fall and winter meals by preserving fresh fruits and vegetables now through canning, freezing or drying.  Freezing is a popular method because it’s quick and easy to do.  High quality results from freezing depend on a few key steps:  fresh high-quality produce,  proper methods of preparation,  proper storage materials and correct freezer temperatures.

Freezing cannot improve the quality of any food, so it’s important to start with the best quality fruits and vegetables at the peak of maturity.  Fruit should be firm yet ripe.  Vegetables should be young, tender, unwilted and garden fresh.

Fruits and vegetables contain enzymes which are slowed down but now destroyed during freezing.  If not inactivated, these enzymes can cause color and flavor changes as well as loss of nutrients.  Blanching is used to inactivate enzymes in vegetables.  In simple terms, during the blanching process the vegetables are exposed to boiling water or steam or a short period of time.  The vegetables are then cooled rapidly using ice water to stop the cooking process.  Blanching times vary for each type of vegetable;  it is important to follow recommended blanching time because over-blanching results in a cooked product and a loss of flavor, color, and nutrients.  Conversely, under-blanching stimulates enzyme activity and is worse than no blanching at all.

Keeping your produce at its optimum quality while frozen depends a great deal on using the proper storage materials.  Storage materials should be moisture-vaporresistant;  durable and leak-proof;  not become brittle and crack at low temperatures;  resistant to oil, grease, or water;  protect foods from absorption of food flavors or odors; easy to seal and easy to mark.  When purchasing containers or flexible bags or wrappings, make sure it is labled as suitable for freezing.

Check your freezer to make sure it is holding foods at 0 degrees Fahrenheit or below.  Use a freezer thermometer to determine whether your freezer is working at the correct emperature.  Storing frozen foods at higher temperatures than 0 degrees Fahrenheit shortens their life.

Freeze foods as soon as they are packed, labeled and sealed.  Make sure not to overload your freezer with unfrozen foods.  Leaving a little space between packages ensures that air can ciruculate around the foods.  Once the packages are frozen, they can then be stored closer together.

For more information on this topic, contact your county’s Michigan State University Extension Office.  MSU Extension educators are located in all 83 Michigan counties to integrate university and community resources to help families succeed.

[Sources:  "So Easy to Preserve" ,  Elizabeth L. Andress, PhD, Judy A. Harrison, PhD, Cooperative Extension Service/The University of Georgia/Athens, Fourth Edition 1999.]

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(Freezing Fruits and Vegetables; University of Minnesota; Nutrition.)

http://www.extension.umn.edu/distribution/nutrition/DJ0555.html

:::::::::::::::::::::FREEZING:::::::FRESH:::::::FRUITS::::::::::::::::::

METHODS OF PACKING FRUITS:

There are three ways to pack fruits for freezing:  sugar pack, syrup pack, and unsweetened pack.  Although some fruits may be packed without sweeteners, the flavor of many fruits is retained better with the use of sugar.  Gooseberies, currants, cranberries, blueberries, and rhubarb give good quality packs with or without sugar.

To freeze fruits using sugar pack, sprinkle the required amount of sugar over the fruit.  Gently stir until the pieces are coated with sugar and juice.

To make sugar syrup, dissolve the needed amount of sugar in cold water.  Stir the mixture and let stand until the solution is clear.

TO FREEZE FRUITS:

1.     Wash and sort fruits carefully and discard parts that are of poor quality.

2.     Prepare fruits as you will use them.

3.     Check the chart for fruit being frozen to see if an anti-browning treatment is suggested.  use ascorbic acid preparation as recommended in the chart or in the manufacturer’s instructions.

4.     Use dry sugar, or sugar syrup in proportions suggested in the chart.  Dissolve sugar needed in cold water.  Stir. Allow to stand until sugar is completely dissolved.  Do not heat.  You may hold sugar syrup 2 days in the refrigerator.  If you are preparing a sugarless pack of fruits that brown, be sure to treat with ascorbic acid or othe anti-browning agents.

5.     Pakc into good plastic bags, freezer containers or freezer jars.  Allow 1/2-inch headspace for expansion.  Pack fruits, such as peaches, that tend to darken, in rigid containers and under the syrup by placing crumpled wax paper between lid and fruit.

HOW TO PREPARE FRUITS FOR FREEZING:

            FRUITS:                                 PREPARATION:

• APPLES (Most firm-fleshed cooking varieties, especially apples suitable for pies or sauces.):     Wash in cold water, peel, core, and cut into pie slices.  An ascorbic acid powder sold in supermarkets to prevent browning of fruit may be used.  Follow package directions.  Fill container, seal, label, date and freeze.  OR:  Soak apple slices in brine solution (1/2 cup salt to 1 gallon water) for 15 minutes.  Drain.  Pack in sugar syrup using 2 cups sugar and 1/2 teasponn ascorbic acid to 1 quart water.  OR:  Wash whole apples, drain, and dry.  Place in freezer bags.  Freeze.  To use for pie, sauce or other cooked dessert, run cold water over each frozen apple just before peeling.  Pell, slice and use immediately.
• APRICOTS (Well-ripened fruits of uniform gold-yellow color.  Apricots are better canned than frozen.):    Wash in cold water and sort.  Dip six fully-ripened apricots into boiling water until skins loosen, about 15 to 20 seconds.  Chill, peel, halve and remove pits.  Fill containers one-third full of syrup–3 cups sugar to 1 quart water with 1/2 teaspoon ascorbic acid.  Pakc apricots in syrup.  OR:  halve soft ripe fruit, steam 4 minutes, crush and pack with 1 cup sugar to 8-9 cups fruit.
• BLACKBERRIES, BOYSENBERRIES, DEWBERRIES, LOGANBERRIES, YOUNGBERRIES AND NECTARBERRIES:  Wash in cold water and sort.  Pack in sugar syrup using 3 cups sugar to 1 quart water.  OR:  Crush and pack in sugar using 1 cup sugar to 7-8  cups fruit.  For pies, pack berries dry without sugar.
• BLUEBERRIES (Any good quality berry, cultivated or wild):   Wash in cold water and sort.  For desserts, pack in sugar syrup using 3 cups sugar to 1 quart water.  OR:  Pack in sugar using 1 cup sugar to 8-9 cups fruit.  For pies, pack dry without sugar or sugar syrup.
• PIE CHERRIES (Any good quality cherry):   Wash in cold water, stem and pit.  For pies, use 1-1/2 to 2 cups sugar to 4 cups cherries for 9-inch pie.  To improve color, add 1/4 teaspoon ascorbic acid.
• SWEET CHERRIES (Choose bright, fully ripe cherries):   Wash in cold water, sort, stem, and pit.  Pack insyrup using 2 cups sugar to 1 quart water, 1/2 teaspoon ascorbic acid, and either 1 teaspoon citic acid or 4 teaspoons lemon juice.
• CITRUS FRUIT MIXES (Available citrus fruits):   Wash, peel, section or slice fruit.  Sprinkle sugar over each layer of citrus fruit, sweetening to taste. Let stand in refrigerator until fruit forms its own juice.  If you wish to keep the mix 3-4 months, add 1/4 teaspoon ascorbic acid to the sugar used for each 2 pints fruit.
• CRANBERRIES (Any good quality fruit):  Wash in cold water, sort and pack without sugar.
• GOOSEBERRIES (Any good cooking variety):   Wash in cold water and sort.  Pack without sugar or syrup or mix berries an sugar called for in pie recipe.
• GROUND CHERRIES (Any available varieties):  Wash in cold water an sort.  Husk, then scald cherries for 2 minutes.  pack in sugar syrup, 3 cups sugar to 1 quart water.
• MUSKMELONS-CANTALOUPES (Use firm-fleshed fruit):  Wash in cold water.  Cut flesh into 1/2-3/4-inch cubes or balls.  Cover with sugar syrup, using 2 cups sugar to 1 quart water.  You can add whole seedless grapes.  Serve partially frozen.
• NECTARINES (Any good quality fruit):   Same as apricots for preparation and packing.
• PEACHES  (Choose well ripened fruit of good quality):   Wash in cold water and sort.  Dip 3 or 4 peaches into boiling water until skins loosen–15-20 seconds.  Chill and peel.  Freeze in a sugar syrup following directions fro apricots.  You may halve, quarter, or slice peaches.  See steps 4 and 5 under “To Freeze Fruits.”   OR:   Freeze non-browning varietieswith dry sugar using 1/2 teaspoon ascorbic acid and 4 cups sugar with 8 pounds fruit (about 4 quarts).
• PINEAPPLE (Any fruit of bright appearance, dark orange-yellow color):   Peel and core.  Dice, slice or cut into wedges.  Cover with syrup, 3 cups sugar to 1 quart water.  OR:  Pack in dry sugar, 1 cup sugar to 8-9 cups fruit.  Do not use uncooked pineapple in geletin molds.
• RASPBERRIES (Red or purple fruit of good quality):   Wash in cold water an sort.  Pack raspberries in syrup, 3 cups sugar to 1 quart water.  OR:  Pack in dry sugar, 1 cup sugar to 7-8 cups fruit.  handle gently.  Pack purple raspberries for jam without sweetening.
• RHUBARB (Select stalks that are crisp and tender and of good red color in early spring.  Do not pic after July 1.):    Remove leaves and woody ends, wash in cold water and cut in 1-inch lengths.  Do not blanch.  For sauce, pack in sugar syrup using 3-1/2 cups sugar to 1 quart water.  For pies, pack in dry sugar using 1 cup sugar to 4 cups rhubarb, or pack without sugar for a few months’ storage.
• STRAWBERRIES  (Choose firm, ripe berries of bright red color, or rich aromatic flavor.):   Wahs in cold water, sort, and stem.  Pakc whole, sliced (preferred), or crushed berries in 1 cup sugar to 7-8 cups fruit.  OR:  Pack whole berries in syrup, 3-4 cups sugar to 1 quart water.

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(Ohio State University Extension; Human Nutrition; Fact Sheet.)

Link:  http://ohioline.osu.edu/hyg-fact/5000/5333.html

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Freezing vegetables is simple and easy.  Freezing costs more than canning or drying, but preserves more nutrients and a fresher flavor if done properly.

Freezing does not completely destroy bacteria, molds, and yeasts but does retard their growth.  Once food is thawed, microorganisms may continue to grow.

Natural enzymes in vegetables cause flavor, color, texture, and nutritive value changes.  Freezing slows enzyme activity but does not stop it.  Frozen vegetables will become tough and lose flavor during storage unless enzyme activity is stopped by blanching before freezing.

Vegetables lose quality rapidly after harvesting.  Harvest only an amount you can prepare to freeze within 2 or 3 hours.  If this is not possible, refrigerate vegetables, then freeze as soon as possible.

SELECTING AND WASHING VEGETABLES

Choose young, tender vegetables to freeze.  Over-mature vegetables may be hard, tough, or flavorless. 

To remove dirt, bacteria, and pesticide residue, wash vegetables thoughly in cold water.  Drain and rinse several times with cold water.  Le4ft vegetables from water to prevent redepositing of dirt and residues.  Peel, trim, and cut into pieces asdirected for each vegetable on the chart included on pages 2 to 3 of this fact sheet.

PACKAGING VEGETABLES

Air leads to flavor loss or off-flavors.  If Moisture evaporates, frozen food becomes dry, tough, and may develop grayish spots called “freezer burn.”  To prevent air exposure and moisture loss, use only moisture-proof, vapor-proof packaging designed for freezing.  Examples are “can or freeze” glass jars, plastic freezing containers, heavyweight aluminum foil, plastic-coated freezer paper, and polyethylene wrap and bags.  Only sealing tape designated for freezer use will adhere at freezing temperatures.  Freezeer bags can be placed in rigid containers for easy stacking.

Pack vegetables tightly in freezer bags or rigid containers.  Squeeze air from bags before sealing.  Leave 1/2-inch headspace for expansion in rigid containers. 

For loose pack, freeze vegetaqbles pieces in a single layer on a tray until nearly solid.  Package at once.  Label and date product and return it to freezer immediately.

FREEZING VEGETABLES

Because water in vegetables expands during freezing and breaks cell walls, thawed foods may “leak” and have a soft texture.  To retain quality, freeze vegetables quickly at lowest possible freezer setting.  Freeze only 2 to 3 pounds of food per cubic foot of available freezer storage space in 24 hours.

STORAGE

Maintain freezer at 0 degrees Fahrenheit (F) or less.  If power fails, keep freezer closed;  food should stay frozen 24 to 48 hours.  If available, protect food with 25 pounds of dry ice per 10 cubic feet of freezer space.  Food can be safely refrozen if it still contains ice crystals.  Some loss of quality and food value will occur.

The more food put into a freezer in a year, the less the operating cost per pound.  Keep an inventory and use the oldest foods first.  Use frozen vegetables within one year.

PREPARING FROZEN VEGETABLES

Most frozen vegetables can be cooked without thawing; corn on the cob should be patrially thawed.  Cook vegetables in 1/2 cup or less of water per pint package.  Drain and season as desired.

GENERAL INSTRUCTIONS FOR FREEZING VEGETABLES:

1.     Choose young, tender vegetables at peak ripeness.  Work with small quantities at a time.

2.     Blanch or scald to stop enzyme action, wilt vegetables for easier packaging, remove earthy flavors and some undesireable bacteria, further clean product,k and “set” color.   Blanch in boiling water or steam.  Hard water may toughen vegetables;  if this occurs, use softened water.

3.     Cool vegetables immediately after blanching in ice water for time equal to blanching time.  Drain thoroughly.  Pack, label, and freeze immediately.

BOILING WATER BLANCH

Use 1 gallon of water per 1 pound of vegetables (2 gallons for leafy greens).  Place vegetables in wire basket or mesh bag; immerse in boiling water.  Cover.  Start counting blanching time immediately.

STEAM BLANCH

Place one layer of vegetables in a wire basket.  suspend in steamer above several inches of rapidly boiling water and cover.  Steam 1-1/2 times longer than boiling water blanch time.

MICROWAVE BLANCHING

Conventional blanching is more reliable than microwave blanching, which is uneven and unpredictable.  If used, follow directions given by microwave manufacturer.  Expect variable results.  Microwave blanching is suitable for small quantities only.

RECOMMENDATIONS FOR VEGETABLES TO FREEZE:

Preparation and boiling water blanch times for common vegetables:

        Vegetable:       Preparation and Boiling Water Blanch Times:

• ASPARAGUS:  Leave whole or cut into 2-inch lengths.  Blanch small stalks 2 minutes; medium stalks 3 minutes; large stalks 4 minutes. Cool promptly and drain.
• BEANS (Green and Yellow Podded):  Snip tips and sort by size.  Cut or break into suitable pieces or freeze small beans whole.  Blanch 3 minutes. Cool promptly and drain.
• BEANS (fresh LIMA):  Shell an sort.  Blanch small beans 2 minutes; medium beans 3 minutes; large beans 4 minutes.  Cool promptly and drain.
• BEETS:  Remove all but 2 inches of top; wash.  Cook tender for 25 to 30 minutes; large beans 4 minutes.  Cool promptly and drain.
• BROCCOLI and CAULIFLOWER:  Trim.  Separate into individual pieces.  Cut broccoli stalks lengthwise.  Soak 1/2 hour in salt brine (4 teaspoons of slat to 1 gallon cold water) to drive out small insects.  Rinse and drain.  Blanch 3 minutes in water or steam blanch 5 iminutes.  Cool promptly and drain.
• BRUSSELS SPROUTS:  Trim.  Soak 1/2 hour in slat brine (see above).  Rinse and drain.  Blanch small heads 3 minutes; medium heads 4 minutes; large heads 5 minutes.  Cool promptly and drain.
• CABBAGE:  Discard coarse outer leaves.  Cut into wedges or shed coarsely.  Blanch wedges 3 minutes and shredded cabbage 1-1/2 minutes.  Cool promptly and drain.
• CARROTS:  Trim and scrape.  Dice or slice 1/4-inch thick.  Blanch cut carrots 3 minutes; whole carrots 5 minutes.  Cool promptly and drain.
• SWEET CORN-ON-THE-COB:  Husk, remove silks, and trim ends.  Use a large kettle for blanching.  Blanch small ears (1-1/4 inch diameter) 7 minutes;  medium ears (1-1/4 to 1-1/2 inch diameter) 9 minutes;  large ears (over 1-1/2 inch diameter) 11 minutes.  Chill in ice water for as long as it takes to blanch or corn may become mushy and develop a cob flavor.
• SWEET CORN-CUT:  Husk, remove silks, and trim ends.  Blanch 4-6 minutes, depending on size of ear.  Chill.  Cut from cob.
• KOHLRABI:  Cut off tops and roots.  Wash and peel tough bark.  Wash and slice 1/4-inch thick, dice in 1/2-inch cubes, or leave whole.  Blanch cubes 1 minute; slices 2 minutes; whole 3 minutes.  Cool promptly and drain.
• MUSHROOMS:  Trim stem ends.  Sort by size.  freeze small ones whole;  slice larger ones.  To prevent discoloration, use 3 teaspoons lemon joice or 1/2 teaspoon ascorbic acid to 1 quart water when blanching.  Blanch whole 4 minutes; sliced, 3 minutes.  Cool and drain.  To Steam Blanch:  Dip for 5 minutes in a solution of 1 teaspoon lemon joice or 1-1/2 teaspoon citric acid to 1 pint water.  Steam whole 5 minutes; buttons or quarters 2-1/2 minutes; sliced 3 minutes.  Sauteed:  Heat small quantities of mushrooms in butter for 3 minutes.  Cool and pack. No blanching is required.
• OKRA:  Cut off stems without opening seed cells.  Blanch small pods 3 minutes; large pods 4 minutes.  Leave whole or slice crosswise.  Cool promptly and drain.
• PEAS (green, English, black-eyed):  Shell small amount at a time.  Blanch green or English for 1-1/2 minutes; black-eyed 2 minutes.  Cool promptly and drain.
• PEAS (edible pod, sugar, or Chinese):  Remove stems, blossom ends, and any string.  Leave whole.  Blanch small pods 1-1/2 minutes; large pods 2 minutes.  Cool promptly and drain.
• PEPPERS, green:  Remove stem and seeds.  halve, chop, or cut into 1/2-inch strips or rings.  May be frozen without blanching.  For use in cooking, blanch halves 3 minutes; strips or rings 2 minutes. Cool, drain, and package.
• PEPPERS, hot:  Wash and stem.  Package leaving no headspace.
• PIMENTOS:  Peel by roasting in oven 400-450 degrees F for 6-8 minutes or until skins can be rubbed off.  Wash off charred skins, cut out stems, remove seeds.  Package.
• POTATOES, IRISH (white):  Plain:  Wash and peel or scrub.  Blanch 3-5 minutes depending on size.  Cool, drain.  French fried:  Use potatoes that have been stored at least 30 days.  Wash, peel, and cut into thin strips.  Rinse in cold water, dry thoroughly.  Fry in hot fat (360 degrees F) about 5 minutes until tender, not brown.  Drain on paper towels.  Cool and package.  Finish browning at serving time in a hot oven (475 degrees F).
• POTATOES, SWEET (orange):  Choose potatoes that have been cured for at least one week.  Sort to size and wash.  Cook until almost tender (in water, pressure cooker, oven).  Cool at room temperature, peel and cut in halves, slice or mash.  To prevent darkening:  Dip whole potato or slices in a solution of 1/2 cup lemon juice to 1 quart water for 5 seconds.
• SPINACH and OTHER GREENS:  Remove damaged leaves and tough stems.  Blanch collards 3 minutes; other greens 2 minutes.  Cool promptly and drain.
• SUMMER SQUASH, ZUCCHINI:  Peel; cut in 1/2-inch slices; blanch 3 minutes.  Steam shredded zucchini 1-2 minutes or until translucent.  Cool promptly and drain.  
• TOMATOES:  Raw:  Wash and dip in boiling water for 30 seconds to loosen skins.  Core and peel. Freeze whole or in pieces.  Use for cooking or seasoning only.  Juice:  Wash, sort, and trim.  Cut in quarters or eighths.  Simmer 5-10 minutes.  Press through sieve.  If desired, add 1 teaspoon salt per quart.  Pour into containers, leaving headspace.   Stewed: Prepare as in juice.  Cover and cook until tender, 10-20 minutes.  Cool and pack leaving headspace.

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(Freezing Fruits and Vegetables; University of Minnesota; Nutrition.)

http://www.extension.umn.edu/distribution/nutrition/DJ0555.html

TO  USE  HOME  FROZEN  PRODUCE:

FRUITS:   Thaw fruit at room temperature in its original package to preserve quality and nutritive value.  If faster defrosting is required, submerge (if watertight) in cool or lukewarm water or follow microwave defrosting instructions.  Serve as soon as defrosted, preferabley while a few ice crystals remain.

VEGETABLES:   All vegetables may be cooked from the frozen state except corn-on-the-cob, which should be partiallydefrosted.  Cook frozen vegetables in a small amount of salted water (about 1/2 cup or less).  Cook only until tender–about half as long as if the same vegetable werefresh. You can use a pressure saucepan for cooking frozen vegetables.  Follow manufacturer’s directions for cooking time.  A pack should be thawed enough to break it up before pressure cooking.