Transcript Freezing - Pender County 4-H

Freezing
Rick Sloan
FCS Agent
What will we learn?
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Principles of Freezing
Freezers
Packaging Materials
Freezing Foods
Shelf-life of Frozen Foods
Emergencies
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Principles of Freezing
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Principles of Freezing
 Does not sterilize food.
 Extreme cold (0oF or colder):
 stops growth of microorganisms and
 Slows chemical changes, such as enzymatic
reactions.
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Advantages of Freezing
 Many foods can be frozen.
 Natural color, flavor, and nutritive value
retained.
 Texture usually better than other methods of
food preservation.
 Foods can be frozen in less time than they can
be dried or canned.
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Advantages of Freezing
 Simple procedures.
 Adds convenience to food preparation.
 Proportions can be adapted to needs unlike
other home preservation methods.
 Kitchen remains cool and comfortable.
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Disadvantages of Freezing
 Texture of some foods is undesirable because of
freezing process.
 Initial investment and cost of maintaining
freezer is high.
 Storage space limited by capacity of freezer.
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How Freezing Affects Food
Chemical changes
 Enzymes in vegetables
 Enzymes in fruit
 Rancidity
Texture Changes
 Expansion of food
 Ice crystals
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Freezers
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Freezer Selection
Consider:
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Size
Shape
Efficiency
Defrosting features
Available floor area
Amount of freezer space needed
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Freezer Selection
What size?
 General Rule
 Allow 6 cubic feet of freezer space per person (3 cubic
feet per person might be adequate if other methods of
food preservation are used).
 Standard Freezer
 Capacity -- 35 pounds of frozen food per cubic foot or
usable space.
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Types of Freezers
Upright
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6 to 22 cubic feet
Convenient
Uses small floor space
Easy to load and unload
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Types of Freezers
Chest
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6 to32 cubic feet
Takes more floor space
More economical to buy and to operate than upright
Loses less air when opened
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Types of Freezers
Refrigerator - Freezer Combination
 2 to 6 cubic feet
 Be sure can set temperature at 0ºF or colder
 Freezer can be above, below, or beside refrigerator
area
 Other features
 Self defrosting or manual defrost
 Receptacle clips - prevent accidental disconnecting
 Door locks and drains for defrosting
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Location and Placement of
Freezer
 Place in convenient, cool, dry, well-ventilated
area.
 Do not place by stove, range, water heater or in
the sun.
 Do not push flush against wall. Leave space for
air circulation and cleaning.
 Be sure freezer is level.
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Packaging Materials
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Packaging Materials
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Moisture-vapor resistant
Durable and leak-proof
Not become brittle and crack at low temperatures.
Resistant to oil, grease, or water
Protects foods from absorption of off-flavors or odors
Easy to seal and mark
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Types of Packaging Materials
 Rigid Containers
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Plastic freezer containers
Freezer boxes with liners
Coffee canisters
Wide mouth canning/freezing jars
 Good for liquids, soft, juicy, or liquidpacked foods
 May be reusable
 Hold their shape and can be stored upright
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Types of Packaging Materials
Non-Rigid Containers
 Bags
 Wrappings - cellophane, heavy-duty aluminum foil,
polyethylene, laminated paper
Good for firm, non-juicy foods
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Freezing Foods
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General Freezing Instructions
Selection
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Freezing does not improve quality.
Choose the highest quality available.
Freeze promptly.
Remember some foods do not freeze well.
Preparation
 Work under sanitary conditions.
 Follow recommended procedures.
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Packing Foods to be Frozen
 Cool food before freezing.
 Ice bath
 Pack in serving size quantities.
 Usually up to 1 quart
 Pack foods tightly.
 Allow for some headspace.
 Vegetables like broccoli and asparagus, bony
pieces of meat, tray packed foods, and breads,
do not need any headspace.
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Packing Foods to be Frozen
 Press all air from bagged foods, seal bags by
twisting and then folding over loose edge
(gooseneck). Secure with string, twist-tie or
rubber band.
 Use tight lid on rigid containers and keep
sealing edge clean. Use freezer tape on loose
fitting covers.
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Washing Fruits and Vegetables
 Wash fruits and vegetables in warm water
before freezer.
 The only exception to this rule is that
blueberries should not be washed before
freezing.
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Labels
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Name of product
Added ingredients
Form of food: halves, whole, or ground
Packing date
Number of servings or amount
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Freezing
 Freeze foods at <0ºF (set freezer at -10ºF at
least 24 hours before freezing foods).
 Freeze foods immediately.
 Do not overload freezer with unfrozen food.
Freeze amount that will freeze in 24 hours -- 2
to 3 pounds of food per cubic foot.
 Pack already frozen foods together so they do
not thaw.
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Freezing
 Place unfrozen foods in contact with surfaces and in
coldest parts of freezer.
 Leave space so air can circulate.
 When food is frozen, organize freezer into types of
food.
 Arrange frozen foods so that the foods frozen
longer can be used first.
 Keep a current frozen foods inventory.
 Check freezer temperature periodically.
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Sweetened Packs for Fruit
Syrup Pack
 Better texture
 Not needed for safety
 Fruits should be covered with syrup
 Place crumpled water-resistant paper in top of
container
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Sweetened Packs for Fruit
Sugar Pack
 Soft sliced fruits (strawberries, peaches, etc.) make
on syrup when mixed with the right proportion of
sugar.
 Layer fruit and sugar.
 Allow it to stand for 15 minutes.
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Unsweetened Packs for Fruit
Dry Pack
 Good for small whole fruits such as berries that
do not need sugar.
 Simply pack into containers and freeze.
 Can freeze on a tray first, so pour easily.
Pectin Syrup
 Good for strawberries and peaches.
 Mix 1 pkg. powdered pectin and 1 cup water.
Bring to boil, boil 1 minute. Remove from heat,
cool, and add 1-3/4 cups more water.
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Unsweetened Packs for Fruit
Water or Unsweetened Juice Packs
 Texture will be mushier.
 Color poorer.
 Freezes harder, takes longer to thaw.
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Packs for Purees or Juices
 Pack as is, with or without sugar.
 Add ascorbic acid if light-colored.
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Artificial Sweeteners
 Can be used in the pectin syrup, juice, or water
packs.
 Or could be added just before serving
 Do not help with color retention or texture, like
sugar does.
 Use amounts on product labels.
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Preventing Fruit Darkening
 The following work well:
 1 teaspoon (3000 mg) ascorbic acid to one
gallon of water
 Commercial ascorbic acid mixture
 Heating the fruit
 The following do not work as well:
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Citric acid solution
Lemon juice
Sugar syrup
Salt/vinegar solution
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Preventing Discoloration during
Freezing
Ascorbic Acid
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Is the most economical.
Use powdered or tablet form.
1/2 teaspoon powdered ascorbic acid = 1500 mg
Crush tablets well.
Use amount specified for each fruit.
In syrup or liquid packs, add powder to liquid.
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Preventing Discoloration during
Freezing
 In sugar or dry packs, dissolve 2 to 3 tablespoons in
cold water and sprinkle over fruit.
 For crushed fruit, purees or juices, mix with fruit
about 1/8 teaspoon per quart.
 Ascorbic Acid Mixtures
 Follow package directions
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Preventing Discoloration during
Freezing
 Citric Acid or Lemon Juice
 Not as effective
 May mask flavors
 Steaming
 Best for fruits that will be cooked before use
 Follow directions in freezing publications
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Freezing Vegetables
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Select young, tender, high-quality vegetables.
Sort for size and ripeness.
Wash and drain before removing skins or shells.
Wash small lots at a time, lifting out of water.
Do not soak.
 Work in small quantities, preparing per
instructions.
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Preventing Flavor and Color
Changes in Vegetables
Water blanching
 Use 1 gallon water per pound of vegetables.
 Place vegetables in blanching basket.
 Lower into vigorously boiling water.
 Cover and begin timing.
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Blanching Vegetables
Steam Blanching
 Use kettle with tight lid and basket.
 Put 1 to 2 inches of boiling water in the bottom of
pan.
 Vegetables should be in a single layer in basket.
 Start timing when covered.
 Takes 1-1/2 times longer than water blanching.
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Blanching Vegetables
Microwave Blanching (not recommended)
 Enzymes might not be inactivated.
 Does not save time or energy.
 Use specific directions and blanch small quantities
at a time.
 After blanching, cool immediately in cold water.
 Change water frequently.
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Types of Pack for Vegetables
Dry Pack
 Pack after blanched, cooled, and drained.
 Pack quickly, excluding air.
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Types of Pack for Vegetables
Tray Pack
 After draining, spread in a single layer on a shallow
pan.
 Freeze firm.
 After first hour, check often.
 Pack quickly, excluding air.
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Freezing Meats and Poultry
 Keep meat or poultry and everything they touch as
clean as possible.
 Keep cold until frozen.
 Never stuff poultry before freezing.
 Store-bought meats must be over-wrapped.
 Freeze meats and poultry using the drugstore or
butcher wrap (drugstore wrap preferred except for
irregular meat cuts).
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Freezing Fish
 Pre-treat as directed to control rancidity, flavor
changes or loss of liquid.
 Package using one of the following:
 Lemon-gelatin glaze
 Ice glaze
 Water
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Lemon-gelatin Glaze
 Mix 1/4 cup lemon juice and 1-3/4 cups water.
 Dissolve 1 packet unflavored gelatin into 1/2
cup of this mixture.
 Heat remaining mixture to boiling and add
dissolved gelatin.
 Cool, dip fish, wrap and freeze.
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Freezing Prepared Foods
 Many can be frozen.
 Follow directions in a credible freezer
publication.
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Foods that Do Not Freeze Well
 Cabbage, celery, cress,
cucumbers, endive, lettuce,
parsley, radishes
 White potatoes
 Cooked macaroni, spaghetti,
rice
 Egg whites
 Meringue
 Icings made from egg whites
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Cream or custard filling
Milk sauces
Sour cream
Cheese
Mayonnaise or salad
dressing
 Gelatin
 Fruit jelly
 Fried foods
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Thawing Foods for Serving
Fruits
 Best if served with ice crystals present.
 Thaw:
 In refrigerator -- 6 to 8 hours per pound of fruit in
syrup
 At room temperature -- 1 to 2 hours per pound
 At room temperature in cool water -- 1/2 to 1 hour
per pound
 In microwave oven - follow manufacturer’s
instructions.
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Thawing Foods for Serving
 Dry sugar packs thaw faster than syrup packs.
 Unsweetened packs thaw the slowest.
 When used in recipes, allow for added sugar
and more juice.
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Thawing Foods for Serving
Vegetables
 Cook without thawing except partially thaw cornon-the-cob and leafy greens.
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Thawing Foods for Serving
Meat, Poultry, and Fish
 Can be cooked when thawed or frozen (might 1-1/2
times longer if cooked frozen).
 Thaw:
 In refrigerator
 In microwave oven (follow manufacturer’s directions)
 In cold water (keep water cold)
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Shelf-Life of Frozen Foods
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Vegetable Storage
Temperature
0ºF
5ºF
10ºF
15ºF
20ºF
25ºF
30ºF
Length of Storage
1 year
5 months
2 months
1 month
2 weeks
1 week
3 days
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Emergencies
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Freezer Emergencies
 If power will be off, set freezer controls to 10ºF
to -20ºF immediately.
 Do not open door.
 Foods stay frozen longer if freezer is full, wellinsulated, and in cool area.
 Full freezer -- keeps 2 to 4 days
 Half full freezer -- 24 hours
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Freezer Emergencies
 If power interruption will be longer than 1 to
2 days, use dry ice:
 50 lbs -- keeps full 20 cubic foot freezer below
freezing for 3 to 4 days
 50 lbs -- keeps half-full freezer for 2 to 3 days
 Keep dry ice on boards or heavy cardboard on
top of food.
 Do not touch dry ice.
 Do not open freezer.
 Ventilate room.
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Refreezing Thawed Foods
 Texture will not be as good.
 General rule:
 Refreeze if freezer temperature is 40ºF or colder or
if ice crystals are still present.
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Best Advice for Freezing
Freeze foods quickly.
 Set freezer temperature at -10ºF 24 hours before
freezing foods.
 Spread packages out until frozen, then stack.
Hold at 0ºF or colder for best quality.
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