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FRUITS and V~G~TABL~S iTHE LlBRARV OF THE

JUN ~ 61':Jblfor FR~~ZING

With suggestions for

choosing suitable

varieties

AGRICULTUJ

EXTENSION SERVICE IN AGRICULTURE AND HOME ECONOMIC

Circular 602

UNIVERSITY OF ILLINOIS • • COLLEGE OF

I" /JJJat:fl ~aCCflJJ • •

Start with fruits and vegetables of high quality.

Sort them carefully and make sure they are clean.

Process quickly according to tested directions.

Pack and seal in air-tight, leak-proof containers.

Place containers in the freezing unit immediately, or take to the locker as soon as possible.

Store at 0° F. or lower.

Remember that speedy, careful, efficient

handling of high-quality fruits and

vegetables is essential.

This circular was prepared by Frances O. Van Duyne, former Professor of Foods, and revised by Mary Keith, Foods Extension Specialist and Assistant Professor of Foods and Nutrition.

Urbana, Illinois Revised March, 1983

Issued in furtherance of Cooperative Extension Work, Acts of May 8 and June 30, 1914, in cooperation with the U.s. Department of Agriculture. WILLIAM R. OSCHWALD, Director, Cooperative Extension Service, University of Illinois at Urbana-Champaign.

The Illinois Cooperative Extensio n Service provides equal opportunities in programs and employment.

(r /

O~J6 How to Prepare Fruits and Vegetables

for Freezing With Suggestions for Choosing Suitable Varieties

FREEZING, when properly done, is a most satisfactory method of preserving many fruits and vegetables. 1iore of the original flavor, color, texture, and nutritive value is

usually retained during freezing than when these foods are preserved in any other way.

Freezing does not, however, add anything to the original qualities of fresh fruits and vegetables. If, therefore, these foods are to be of highest quality after they are frozen, they must be of highest quality in their fresh state, and well-tested ways of preparing them for freezing must be carefully followed.

SELECTING FRUITS AND VEGETABLES

Choose only the very best quality

Select fruits and vegetables that have been grown under favorable weather and soil conditions. Remember that freezing does not improve these foods; in fact, undesirable characteristics are likely to be magnified. Seeds in berries and woodiness in asparagus and green beans are more noticeable after these vegetables have been frozen and held in freezer storage than they were before.

Most vegetables and certain fruits should be prepared for freezing as soon after picking as possible. If they are held after harvesting, they usually lose some of their flavor and nutritive value.

Use fruits and vegetables suitably mature

The maturity of fruits and vegetables to be frozen ·is extremely important in determining the quality of the product. They should be picked at the stage when they are best for eating. Avoid overmature or starchy corn and peas. Select young and tender snap beans which have been picked before the pods have grown to more than two-thirds full size.

Do not use hard or oversoft frnit. Fruit ripened on the tree,

3

4 Circular No. 602

bush, or plant and prepared immediately for freezing is usually better than fruit picked at a less mature stage and subjected to delays between harvesting and freezing.

Choose a superior variety

Varieties that excel as fresh products have been found, in general, to be suitable for freezer storage. Ratings for a number of varieties of fruits and v~getables are shown on pages 15 and 16. These ratings are based on tests made in the food research laboratory of the Home Economics Department at the University of Illinois. They are offered only as a partial guide to selection, since many common Illinois varieties not yet tested will doubtless gi\Oe good products when frozen. A few of the fruits are not grown in Illinois. Their ratings are therefore based on lots that were bought on the local market, as Illinois people would usually buy them.

WASH AND SORT CAREFULLY

Wash the fruit or vegetable thoroughly in clean cold water. Handle fruit gently, a small amount at a time. Discard all material that is injured, bruised, or otherwise not up to standard. This treatment will remove dirt particles and reduce the number of bacteria.

Use special care in sorting because even a small quantity of inferior material can spoil the flavor of several cartons of food.

BLANCH VEGETABLES ACCORDING TO DIRECTIONS

Vegetables that are to be frozen must first be blanched (scalded) if the greatest possible amounts of color, flavor, texture, and nutritive value are to be retained. Of the vegetables that have been tested, rhubarb is the only one that is satisfactory \\"hen it is not blanched before being frozen. Precooking beets and winter squash makes them easier to handle than if they are blanched. Tomatoes are simmered before the juice is extracted.

To blanch vegetables in boiling water, weigh a small quantity of the vegetable in a wire basket or sieve, and lower into a kettle of boiling water (see Fig. 1). I-Iold there for the required time (see table on pages 6 and 7). Count the time from the moment the vegetable is put into the water.

5 Preparing Fruits and Vegetables for Freezing

Weighing the vegetable and using the right amount of boiling water are necessary for a careful job of blanching. Here 2 pounds of spinach are ready to go into 10 quarts of boiling water for one minute. (Fig. 1)

Keep the cover on the kettle during the blanching period, and heat the water continuously. Usually the water will not boil again while the vegetahle is heing hlanched.

\Vhen the vegetahle has heen in the water the required time, lift the basket or sieve out of the water and plunge it and its contents into a large container of cold water. I-lave container under cold-water faucet so you can cool the vegetable quickly in running water (see below). Ice water may be used instead of running water.

After blanching the vegetable, cool it at once in a large kettle of cold running water. When running water is not available, ice water or several kettles of cold water can be used. (Fig. 2)

If you do not have running cold water or ice, use several containers, sometimes as many as four. When the water gets slightly warm in one, put the vegetables in the next one. (Continued on page 8)

6 Circular No. 602

(Table 1)

V E G ET A B L E S: How to Prepare for Freezer Storage

First carefully wash the vegetable and discard all material not up to standard, then follow directions given below.

Asparagus Discard tough stalks. Cut tips either into lengths to fit the cartons or into pieces 1 inch long and then blanch .....

Beet greens Use tender young leaves. Wash thoroughly and blanch ........... ...... ..

Beets Use tender beets not more than 2 inches in diameter. After blanching (actually cooking in this instance) cool, remove skins and slice or dice ............. ...

Broccoli Use heads and tender portions of stalks. Cut through stalks so that pieces of heads are not more than 1 inch across, and then blanch ............ ..... . . . .

Brussels sprouts Select fairly small solid sprouts of good quality. Halve larger ones before blanching...........................

Cauliflower Divide flowerlets into pieces about 1 inch long and % to 1 inch in diameter, and then blanch ..... ............... .

Corn Use sweet corn in the milk stage. Remove husk and silks. Cut corn from cob after blanching...................

Dandelion greens Use only tender young leaves. Wash thoroughly, then blanch ..............

Lima beans Hull green lima beans of even maturity, then blanch ............... . ...... . . .

Quantity of

vegetable

lIb.

lIb.

lIb.

lIb.

lIb.

lIb.

8 medium ears

lIb.

lIb.

BLANCHING

Amount of boiling water

6 qt.

6 qt.

3 qt.

5 qt.

5 qt.

6 qt.

5 qt.

8 qt.

4 qt.

Time in water

3 min.

2 min.

25-30 min.

3-4 min.

4 min.

4 min .

4 min.

3 min.

3 min.

Count blanching time from moment vegetable Is placed in boiling water.


(Table 1 Concluded)

V E GET A B L E S: How to Prepare for Freezer Storage

First carefully wash the vegetable and discard all material not up to standard, then follow directions given below.

Mushrooms Use tender button or medium-size mushrooms. Wash in 2% salt solution (172 level tablespoons of salt to 1 qt. water). Cut off ends of stems. Brown lightly in butter 3 to 5 min. or blanch button size 3 min., medium size 5 min.

Peas Hull sweet, tender peas, then blanch . . .

Rhubarb Use tender stalks, cut into ~ inch pieces, and blanch. . . ... . ............

Snap beans Choose young tender stringless beans. Remove ends, cut into 1-inch pieces or lengthwise strips, and blanch ...... .

Soybeans Use green soybeans of edible variety. Blanch in pods, then cool and hull ... ..

Spinach Select tender green leaves and stalks. Wash thoroughly and blanch ... . . . . . ..

Squash, summer Choose young tender squash. Slice and cut into pieces, then blanch (or cook as for serving, put through sieve, cool, and package for freezing) . . .... . . . . . ..

Squash, winter Halve, remove pits, peel, and cube. Steam or boil until tender. Put through sieve, cool, and package for freezing ... .

Swiss chard Use tender young leaves. Wash thoroughly and blanch .................. .

Tomato iuice Wash tomatoes, quarter, and simmer for 10 minutes. Strain off juice and add 72 teaspoon salt for each pint .. .... .. .

Quantity of

vegetable

1 lb.

1 lb.

lIb.

1 lb.

lIb.

lIb.

lIb.

x x

lib.

x x

BLANCHING

Amount of boiling water

4 qt.

4 qt.

272 qt.

4 qt.

2 qt.

5 qt.

5 qt.

x x

4 qt.

x x

Time In water

3-5 min.

172 min.

172 min.

3 min.

5 min.

1-2 min.

4 min.

x x

2 min.

x x

8 Circular No. 602

Just as soon as the vegetable has cooled, drain it thoroughly. It is important to remove all excess water. Pack at once.

(1 f the bla1lc/zi1lg Il?ettle is large enoll.r;h, 2 pou1lds of a ve.r;etable may be put in twice the amolfnt of boiling water i1ldicated in Table 1. Blanch for the same length of time.)

Blanching water can be used more than once - as long as it stays clean and is not too discolored. Be sure to add enough water each time to bring the total amount to the full measure. Remember that the water should always be boiling when the vegetable is put into it.

USE SUGAR OR SUGAR SIRUP WITH FRUITS

Sirup may preserve the color of light fruits, such as apricots and peaches, that darken with air contact. Juicy fruits are better packed dry with sugar, as the sugar draws the fruit's juices to form the sirup. Blueberries and cranberries freeze well without sugar; raspberries and strawberries are only fair. Generally, dry packing is better for pies, and sirup packing is better for dessert uses. Use V:z cup sugar to one quart of fruit for dry packing.

For directions for processing fruits see pages 9 and 10. To make sirups with approximately the correct proportions of sugar, use the following amounts of water with each cup of sugar:

Sirup Sugar Water 30 percent. . . . . . . . . . . . . . . . . . . . . . 1 cup 2 cups 40 percent. . .. . . . . . . . . . . . . . . . . . . 1 cup 1~ cups 50 percent.. .. . . . . . . . . . . . . . . . . .. 1 cup Ys cup 60 percent. . .. . . . . . . . . . . . . . . . . .. 1 cup Y2 cup

The sugar may be dissolved in the water by stirring. I f, however, you heat the mixture to dissolve it more quickly (boiling is not necessary), be sure to cool it before usillg.

One-half cup of sugar and Vz cup of light corn sirup can be used instead of 1 cup of sugar with the above amounts of water.

Ascorbic acid helps prevent brownillg. Peaches and apricots brown less readily if ascorbic acid (vitamin C) is added to the sirup in which they are packed for freezing. Commercial preparations containing yitamin Care sold in some grocery stores under different trade names. Follow the directions of the manufacturer. Tablets or crystals of ascorbic aciJ can usually be obtained from drugstores. Dissolve three 50-milligram tablets in the amount of sug-ar sirup needed for a pint carton of fruit (abollt I cup of sirup), or add ~ teaspoon of crystals to 4 cups of sugar sirup. Tablets may make the sirup cloudy.


(Table 2)

FRUITS: How to Prepare and Pack for Freezer Storage

Fruit

Apples, slices. . . • . • • •

Apples, as sauce..•...

Apricots ...•...••••••

Blackberries and dewberries ....•••.

Blueberries ......••••

Cantaloupe .•.•••••••

Cherries, sweet •••••••

Cherries, sour ..••••••

Cranberries .••.••••••

Gooseberries..•••••••

Grapefruit •.•••••••••

Preparation

Select firm, ripe, tart fruit. \Vash, core, peel, and slice in 16ths. Or do as indicated above and then blanch slices in steam for 3 minutes.

Core, peel, and cut into 8ths. Simmer with water until soft. Put through SIeve.

Use fully ripe but not soft apricots. Peel, halve, and pit.

Choose fully ripened, uniform berries. \Vash and sort.

Use large ri pe berries. \ Vash thoroughly and discard any that are soft.

Select firm ripe fru:t. Remove seeds and rind. Cut in to small wedges.

Use firm ripe fruit. \Vash, and remove stems.

Use firm ripe fruit. \Vash, and remove stems and pits.

Choose bright, shiny, firm berries. \Vash thoroughly and sort.

Select green or ripe berries. \Vash, and remove stems.

Use firm, well-shaped fruit which is heavy for its size. Peel, scpara te sections, and carefully remove the membranes.

Type t'f pack

Cover with 40% sirup.

Pack plai n or cover wi th 40% sirup.

Add sugar to taste.

Cover with 40 to 50% sirup.

Cover with 40% sirup or add Y2 c sugar to 1 qt. fruit as dry pack.

Pack plain or cover wi t h 30% sirup or dry pack as for blackberries.

Cover wi th 40% sirup.


l\lix 1 c sugar with 3 c cherries.

Pack plain or cover wi th 50% sirup.

C over wi th 60% sirup.

Cover white sections wi th 40% sirup; cover pink with 30% sirup. Juice may be used in making sirup.

c = cup. Table is concluded on next page.

10 Circular No. 602

(Table 2 Concluded)

FRUITS: How to Prepare and Pack for Freezer Storage

Fruit

Grapes, seedless...... 1

Grapes, seeded......• 1

Honeydew melon ..... 1

Peaches.•......•..•. 1

Pineapple .........•• 1

Plums, prune••..••••• 1

Plums, red ...•..•.••• 1

Raspberries .•...•.••• 1

Strawberries I Whole .......•••••

Sliced or crushed..•. 1

Watermelon •..••.... 1

c = cup.

Preparation

Discard any soft or bruised fruit. \Vash, and remove stems.

Sort carefully and discard any soft fruit. \Vash, and remove stems. Cut in hal ves and remove pi ts.

Select firm ripe fruit. Remove seeds and rind. Cut in to small wedges.

Use only firm ripe fruit. Peel and slice enough for one carton at a time. Pack and cover with sirup immediately.

Use ripe fruit. Slice, pare, remove core, and cut into wedges.

Choose ripe, unbruised fruit. \Vash, halve, and remove pits.

Select ripe fruit without any soft spots. Halve, remove pits, and then quarter.

Choose ripe juicy berries (purple or red raspberries are better than black) . Sort and wash.

Select firm ripe berries. Wash and hull.

Prepare in same way as for whole strawberries. Then slice or crush.

Choose firm, ripe fruit. Remove seeds and rind. Cut into small wedges.

Type of pack




Cover wi th 50 to 60% sirup or dry pack.

Cover with 30 to 40% sirup or dry pack.



Pack plain; or (better) mix 1 c sugar with 5 c fruit; or (best) cover wi th 30 to 40% sirup.


Mix 1 c sugar with 5 c sliced or crushed fruit.



PACKAGING AND FREEZING

Choose a satisfactory container

Use sturdy containers of appropriate size and shape that can be sealed tight and that will not leak. The more nearly moisture-proof and vapor-proof a container is, the better the frozen product will be.

Several types of containers are on the market: rectangular cartons to be used with plastic bags, waxed cartons, glass freezer jars, and containers of aluminum, plastic, or tin. Tight seals can be obtained in most plastic bags by twisting and using rubber bands or paper-covered wire closures. A double seal made in this way affords good protection. Some of the especially prepared bags can be sealed with the heat from an electric curling iron, flat iron, or sealing iron. Different types of containers and a bag closure being used for sealing are pictured on the next page.

Package vegetables after cooling As soon as the vegetables are cooled after blanching, drain them thoroughly, then pack them and seal the containers. Rectangular cartons with plastic bags are very satisfactory for packaging vegetables.

Package fruits quickly

Put fruit in containers and cover immediately with sugar sirup, unless dry sugar is to be used. If you are using dry sugar, mix it thoroughly with the fruit before putting the fruit in the package. As soon as this is done, seal the package.

Be sure to leave space at the top of the package if you are covering the fruit with sirup or if juicy fruit is mixed with sugar. This will allow room for the contents to expand during freezing. Leave Yz inch for a pint container, 1 inch for a quart container.

Label containers

Most locker companies provide materials for stamping and labeling packages at the locker. If packages are to be kept in a home unit, be sure to label each container with the name of the product and the date on which it was prepared for freezing.

12 Circular No. 602

Cylindrical cartons, glass jars, and tin cans are easy to fill and not likely to leak. These take up more space than rectangular containers, however, and some cartons are not moisture-vapor proof. (Fig. 3)

Rectangular cartons save freezer space. Those made of moisture-vapor proof materials that can be sealed tight are very satisfactory. (Fig. 4)

A rectangular carton with a plastic bag makes a good container for vegetables. The bag may be sealed with a paper-covered wire closure or rubber band. Seals must be air-tight. (Fig. 5)


Put foods in freezer without delay

When the containers are filled and sealed, put them in the home freezing unit or take them to the locker. If the trip to the locker cannot be made immediately, the containers can be left in the refrigerator for a short time but not longer than 3 or 4 hours. The temperature of the refrigerator should be about 38° to 45° F.

Remember that the shorter the time between harvesting and freezing fruits and vegetables, the better they will be.

Store at 0° F. or lower

The temperature of freezer storage should be 0° F. or lower to maintain the best quality in fruits and vegetahles. \Vhen the temperature is higher than 0° F., undesirable changes in flavor, color, and texture may take place. The longer the period of freezer storage the more noticeable these changes hecome.

PREPARING FROZEN FOODS FOR SERVING

Keep fruits and vegetables frozen until needed

Unless the packages can be kept frozen at home, only a few should be taken out of the storage locker at one time. Once food has been removed from a freezer, it should be cooked or used as soon as possible. A fter frozen foods have thawed, the bacteria in them multiply and the food rapidly deteriorates in flavor, texture, and nutritive value.

Thaw fruits iust in time for serving

Frozen fruits may be thawed in the refrigerator, or at room temperature, or hy putting the container in cold running water. They are more appetizing if served while a few ice crystals are still present. Approximate times for thawing pint containers of sliced peaches packed with a 50 percent sugar sirup are 12 hours in the refrigerator, 3 hours at room temperature, and 1 Vz hours in cold running water. These times vary with the size of the container, the fruit being thawed, the type of pack, and the temperature in the refrigerator or room or the temperature of the water.

Leave containers sealed until the fruit is to be served. This precaution is especially important with frozen peaches, since they darken very quickly when thawed and exposed to the air.

14 Circular No. 602

Frozen fruits can be served in several ways. 1\1any of them can be used plain or mixed with other fruits. They are good as sauces for ice cream or shortcake, and they make excellent pies and cobblers. Cranberries can be used in raw cranberry relishes or cooked as a sauce. Frozen apple slices are best when they are stewed or used in pies.

Do not thaw vegetables before cooking

To prepare vegetables for the table, take them from the container and place them immediately in a small amount of boiling salted water (see table on tlzis page). \Vhen a vegetable is frozen in a solid mass (for example, spinach), break it into smaller pieces as it thaws in the hot water.

Count the cooking time from the moment the water returns to boiling after the vegetable has been added.

1\1ushrooms and squash are exceptions to the above directions. Mushrooms can be sauteed (fried lightly and quickly) in butter. Squash should be first heated in the top of a double boiler. It can then be prepared for serving in any way that cooked fresh squash is customarily prepared.

(Table 3)

DIRECTIONS FOR COOKING FROZEN VEGETABLES

Boiling BoilingVegetable Boiling Vegetable Boilingsalted salted(pint carton) time (pint carton) time water water

cups minutes cups minutes Asparagus ......... Y2 4 to 6 Soybeans . . .. . . . ... . ;Y.l 10 Beet greens ........ ;Y.l 5 to 7 Spinach . ...... .. ... ;Y.l 4 to 6 Beets ..... . ....... Y2 3 to 5 Swiss chard ..... . ... ;Y.l 8 to 10 Broccoli . ... . ...... Y2 5 to 7 Brussels sprouts . ... 1 10 Squash Cauliflower .... . ... Y2 3 to 5 I] blanched before freezing, thaw in Corn .............. Y2 2 to 4 top of double boiler. Boil over direct Dandelion greens ... ;Y.l 7 to 10 heat 2 to 4 minutes. Add sa lt. Lima beans .. . ..... ;Y.l 12 to 15 If precooked before freezing , heat in Peas.............. Y2 6 to 8 top of double boiler. Add salt. Snap beans

Rhubarb ... Use Y2 c sugar in ~ c boil. 1 inch pieces ..... ;Y.l 7 to 10 ing water and buil for 2 min utes. Lengthwise strips ;Y.l 5 to 7


Corn, peas, and snap beans are also very good cooked by a "butter boil" method. Add a pint carton of vegetable to 1 tablespoon of butter or margarine, 3 tablespoons of water, and Y2 teaspoon of salt in a heavy saucepan. Cook covered for 7 or 8 minutes, stirring once during the cooking period.

SUITABILITY OF SOME VARIETIES

Not all varieties of fruits and vegetables freeze equally well. The following ratings apply to those varieties that have been tested in the Home Economics food research laboratory at the University of Illinois. As these tests are continued, other varieties commonly grown in Illinois will doubtless prove satisfactory.* Each rating is an average of a number of tests. Four descriptive ratings are used here: very good, high good, good, and low good. Varieties of fruits and vegetables which rated high fair, fair, or low fair and varieties of vegetables not grown extensively in Illinois at present are not included.

VEGETABLES

Asparagus - Good: l\Iary vVashington.

Beet greens - Good: Early vVonder. Low good: Detroit Dark Red.

Beets - High good: Detroit Dark Red, Early vVonder.

Broccoli - High good: Early Green Sprouting, Italian Green Sprouting.

Cauliflower - Good: Snowball.

**Corn - High good: Golden Cross Bantam, Early Sunglow, Iochief, V ictory Golden. Good: Carmel Cross. Low good: Gold Rush, l\larcross.

Lima beans - Good: Fordhook 242. Low good: Henderson's Bush.

Peas - Very good: Large Podded Little Marvel. High good: Little l\lan-el , \VanJo, \Visconsin Early Sweet. Good: Thomas Laxton Dark PodJed. Low good: Laxton's Progress.

Rhubarb - High good: Strawberry, Victoria.

**Snap beans - High good: Asgro',v Stringless Dlack Valentine, Burpee Stringless Greenpod, Improved Commodore, Pencil Pod mack Wax. Good: Asgrow Stringless Greenpod, Cherokee Wax, Giant Stringless Greenpod, Improved Tendergreen, Kinghorn \Nax, Logan, Rival, Topcrop, \Vade. Low good: Kentucky vVonder.

* For other varieties which are rccommended for I11inois gardens, see Ill. Agr. Ext. Ser. Cir. 1150, Vegetable Gardening for Illinois.

**\'ariations in seasons and in degree of maturity, difficulties in securing representative samples, and possibly other factors may explain the difIerences in the ratings of some closely related strains and varieties.

16 Circular No. 602

Soybeans- Very good: ITokkaido. High good: Favorite, Jogun, Kia.Good: Aoda, Bansei, Funk's Delicious, Giant Green, Ilahto, Sanga.

Spinach - High good: Blight Resistant Savoy, Bloomsdale Long Standing, Early Ilybrid # 7, King of Denmark. Good: America.Squash, summer Good: Bush Scallop, Prolific Straightneck, ZucchiniBlack Italian IIybrid. Squash, winter - High good: Blue Hubbard, Buttercup, Butternut. Good:Delicious, Des 11oines. Swiss chard - High good: Strawberry. Good: Lucullus.

FRUITSApples - Good, sliced: Jonathan, Stayman. Low good, sliced: GoldenDelicious, \Villowtwig, \Vinesap. Very good as sauce: Jonathan, Stay

man, \Villowtwig, Winesap. Good as sauce: Golden Delicious, Grimes,Transparent. Apricots - Good: Royal,t Tilton.t Blackberries and dewberries Very good: Boysen, Logan, Young.Good: Alfred, Brainerd, Eldorado.Blueberries-High good: Jersey,t Rubel.t Good: Rancocus.tCherries - Very good: Montmorency. Good: Bing.tGooseberries - Good: Poorman.Grapes - Good: Thompson Seedless.t Low good: Red l\1alaga.tPeaches - High good: Elberta, Rio Oso Gem.t Good: Hale Haven,t Red

Haven.t Plums - Good: Santa Rosa.t Raspberries - High good: Sodus (purple). Good: Latham (red). Low

good: Chief (red). Strawberries - High good: Blakemore, Pocahontas, Good: Catskill,Chesapeake, Dixieland, Premier, Vermilion.

t These varieties were purchased on the market. The quality of the purchasedfruit lowered the rating of some of the frozen products.

To 8-84-262M-lm10M-4-87~7084

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