3.5: Freezing

Learning Objectives

• To demonstrate that freezing is one of the most effective ways of preserving the natural color, texture and flavor of foods.
• To illustrate the relative effectiveness of various methods of preparing fruits and vegetables for freezing.
• To illustrate the effect of freezing on a variety of prepared foods.

NOTE: This lab is designed to illustrate the effects of freezing methods on a variety of fresh and prepared foods. Some of the methods outlined below are examples of processes that will not result in a standard product.

General Laboratory Instructions

This lesson is divided into two periods several weeks apart.

Preparation day

Once food has been prepared it should be frozen as quickly as possible. Cartons or packages should not be stacked or allowed to touch each other until they are frozen solid. When the food is completely frozen it may be stacked on freezer shelves.

Each frozen product should be labeled with masking tape as follows:

• Food, Treatment, and Date Frozen;
• Student Initials, Course Number, Lab Section

Evaluation Day

Place all foods in refrigerator 24 hours before class time.

Follow individual directions for reheating frozen food and preparing fresh products for comparison.

Laboratory Problems

1. Apple slices
   1. Dry pack (untreated)
   2. Dry sugar pack
   3. Steamed
   4. 35% syrup pack
   5. 35% syrup and commercial anti-darkening preparation
   6. 35% syrup plus lemon juice
2. Vegetables: Cauliflower and Carrots
3. Apple and Cherry Pies
4. Gelatin
5. Pudding
6. Spanish Rice
7. Macaroni and Cheese
8. Spice Cake
9. Egg Salad
10. Ground Beef Patties

Apple Slices

Preparation Day:

1. Wash, sort, pare, and slice apples. Use 1 apple for each part of the lab problem.
2. Treatments A-F pack in individual quart-size, labeled, freezer bags; exhaust air and fasten securely.
3. Protect these bags during storage by packing them together in 1 gallon-size freezer bag.
4. Freeze immediately.

Evaluation Day:

1. Place freezer bags in lukewarm water for 20 minutes to thaw.
2. Display samples in individual labeled sauce dishes.
3. Compare effectiveness of freezer treatments and canning.
4. Record your conclusions for obtaining standard frozen apple slices.

Observations and Explanations

Type of Treatment Before Freezing	Appearance	Texture	Flavor
A Dry pack (untreated)
B Dry sugar pack: ¼ cup sugar for each 4 parts fruit
C Fruits steamed for 3 minutes
D* ¼ cup 35% syrup pack*
E* ¼ cup 35% syrup* and ¾ tsp. commercial anti-darkening preparation
F* ¼ cup 35% syrup*, fruit sprinkled with 1 tsp. lemon juice

*For Treatments D, E, F: To prepare 35% syrup, bring 1 cup sugar and 2 cups water to a rolling boil. Chill before adding other ingredients or apple slices.

Freezing Vegetables – Cauliflower and Carrots

Preparation Day:

Unblanched Vegetables

1. Wash, peel (carrots), and slice or chop vegetables. Use 1 cup vegetable for each part of the lab problem.
2. Pack in individual small labeled plastic bags, exhaust air, and fasten securely.
3. Protect these bags during storage by packing them together in gallon-size freezer bag.
4. Freeze immediately.

Blanched Vegetables

1. Wash, peel (carrots), and slice or chop vegetables. Use 1 cup vegetable for each part of the lab problem.
2. Boil at least 1½ quarts of water for each cup of raw vegetable. Lower vegetable in basket into water and cover. Time from the moment the vegetable is immersed in water. Keep heat at high setting during blanching. Blanch carrots 2-3 minutes and cauliflower 3 minutes, or until center of vegetable is hot.
3. Chill immediately in at least two quarts of iced water. When vegetables are cool, drain thoroughly.
4. Pack in individual small labeled plastic bags, exhaust air, and fasten securely.
5. Protect these bags during storage by packing them together in gallon-size freezer bag.
6. Freeze immediately.

Evaluation Day:

1. Examine, cook, and evaluate blanched, unblanched, and fresh vegetables.
2. Record observations and explanations of changes occurring during frozen storage, comparing these vegetables whenever possible with similar canned products.
3. Record your conclusions for obtaining standard frozen vegetable products.

Observations and Explanations

Treatments	Appearance	Texture	Flavor
Carrots
A. Fresh
B. Blanched
C. Unblanched
D. Canned
Cauliflower
A. Fresh
B. Blanched
C. Unblanched

Freezing Prepared Foods – Apple and Cherry Pie

Preparation Day:

Double apple and cherry pie recipes on page 220, 221 to make 2 small pies. Use refrigerated pie crust and disposable pie tin. Mix ⅛ tsp. ascorbic acid with sugar in recipe when making apple pie.

1. Bake first pie, cool, wrap in plastic wrap and foil, label and freeze.
2. Prepare second pie (without cutting vents in crust), wrap in plastic wrap and foil, label and freeze unbaked.

Evaluation Day:

1. Prepare and bake fresh cherry and apple pies.
2. Bake unbaked pie after refrigerating overnight. Unwrap and cut vents in upper crust. Bake at 450°F for 15-20 minutes. Lower heat to 375°F to finish baking, approximately 20-30 minutes.
3. Thaw pre-baked pie in refrigerator overnight. Freshen by heating in a 350°F oven approximately 35-40 minutes. Place aluminum foil loosely over top of pie to prevent excessive browning.
4. Record your observations. (See page 221 for description of a standard two-crust pie).

Observations and Explanations

Characteristics	Pie	Fresh	Baked after Freezing	Baked before Freezing
Crust: appearance, crispness, and tenderness	Cherry
	Apple
Filling: appearance, consistency, and flavor	Cherry
	Apple
General Eating Quality	Cherry
	Apple

Freezing Prepared Foods – Gelatin

Preparation Day:

1. Mix ½ of 3 oz. package (3T plus 1½ t) of flavored gelatin following package directions.
2. Pour into a plastic freezer container.
3. Let gel, cover, and freeze.

Evaluation Day:

1. Unmold frozen sample of gelatin into casserole dish.
2. Prepare ½ of 3 oz. package (3T plus 1½ t) of flavored gelatin according to package directions and let gel.
3. Compare the two products and record your observations.

Characteristics of the Standard Product for Gelatin:

Appearance	Texture	Flavor
Clear. Retains the shape of mold.	Firm, yet resilient. Neither rubbery nor watery.	Mild, characteristic fruit flavor.

Freezing Prepared Foods – Chocolate Pudding

Preparation Day:

1. Prepare chocolate cornstarch pudding, page 111, or prepare ½ of 3 oz. package (3T plus 1½ t) pudding. (Do not use instant pudding mix.)
2. Pour into labeled plastic freezer container.
3. Let cool, cover, and freeze.

Evaluation Day:

1. Thaw pudding.
2. Prepare a fresh sample of chocolate cornstarch pudding according to directions on page 50 or prepare ½ of 3 oz. package (3T plus 1½ t) pudding.
3. Compare the two products and record your observations (see page 111) for characteristics of a standard cornstarch pudding.)

Observations and Explanations

Product	Appearance	Texture	Flavor
Gelatin	Fresh
	Frozen
Cornstarch Pudding	Fresh
	Frozen

Freezing Prepared Foods – Spanish Rice Casserole

Spanish Rice Casserole

⅓ cup long grain polished rice	Dash cayenne
¼ tsp. salt	2 tbsp. chopped green pepper
¾ cups water	1 cup canned tomatoes and juice
3 strips bacon	Salt to taste
¼ cup chopped onion

Boil rice, salt and water according to directions:

Put rice, water, and salt in heavy saucepan; cover with tight fitting lid. Bring to a full boil; reduce heat to very low boil and cook until done,* approximately 15-25 minutes depending on variety of rice and temperature. (Add more water if necessary to prevent scorching.)

Fry bacon over low heat in sauté pan until crisp. Remove and crumble bacon. Sauté onion in bacon drippings until tender. Pour off excess fat. Add cooked rice, bacon, and other ingredients. Pour into 1-pint baking dish and follow assignment directions for freezing or baking.

Preparation Day:

1. Prepare one recipe of Spanish Rice Casserole, slightly undercooking the rice.
2. Pour into casserole dish but do not bake. Cover and freeze in plastic bag

Evaluation Day:

1. Unwrap the food and bake covered at 350°F until bubbling around the edges, approximately 1 hour. NOTE: Some casserole dishes do not withstand freezer-to-oven temperature changes. For these do not preheat oven.
2. Prepare one recipe Spanish Rice Casserole and bake at 350°F for 30 minutes.
3. Record your observations.

Observations and Explanations

Spanish Rice	Long Grain Polished Rice
Characteristics	Fresh	Frozen
Appearance
Flavor
Texture

Characteristics of Standard Product:

• Rice grains: firm, yet tender; not gummy or watery
• Green pepper: comparable to fresh cooked
• Bacon: fresh smoked flavor; not rancid
• Tomatoes: comparable to fresh cooked
• Onion: comparable to fresh cooked

Freezing Prepared Foods – Macaroni and Cheese

Preparation Day:

1. Prepare recipe for macaroni and cheese, slightly undercooking macaroni. Do not bake.
2. Pour into casserole dish but do not bake. Cover and freeze in plastic bag.

Macaroni and Cheese

⅔ cup uncooked macaroni	84 grams or 3 oz. shredded Cheddar cheese (3/4 cup)
3 cups water	1 cup thin white sauce
2 tbsp. dry bread crumbs	1 tsp. butter
White Sauce:
1 Tbsp butter or margarine	1 Tbsp flour
1/8 tsp salt	1 cup milk
Melt fat in saucepan. Blend in flour and salt; remove from heat. Add milk, stirring to blend; return to heat and stir gently while heating quickly to a full boil, remove from heat.

Cook macaroni in boiling salted water until almost tender. Drain and rinse with hot water. Prepare white sauce. Wait 45 seconds, and blend cheese into sauce. Stir in macaroni; turn into 1-pint baking dish. Melt butter, mix with crumbs, and sprinkle over top. Do not bake until evaluation day. Set baking dish on wire rack in pan of hot water and bake uncovered at 350°F for 30 minutes.

Evaluation Day:

1. Unwrap frozen macaroni and cheese. Bake uncovered in water bath at 350°F until heated through and bubbling around the edges, approximately 50-60 minutes.
2. Prepare and bake one recipe macaroni and cheese.
3. Record your observations, noting especially the effect of freezing on the macaroni texture, the cheese, and the white sauce thickened with flour. See page 147 for a description of the standard product.

Observations and Explanations

Macaroni and Cheese	Fresh Casserole	Frozen Casserole
Appearance
Flavor
Texture
Consistency

Freezing Prepared Foods – Spice Cake

Quick Mix Spice Cake

½ cup sifted flour	⅛ tsp. mace
⅓ cup sugar	⅛ tsp. cloves
¼ tsp. salt	2 tbsp. shortening
¾ tsp. baking powder	¼ cup milk
¾ tsp. cinnamon	½ egg
¼ tsp. nutmeg	¼ tsp. vanilla

Grease a 5X5 inch baking pan and line with waxed paper. Sift together flour, sugar, salt, baking powder, and spices three times. Add shortening and approximately half the milk. Beat at medium speed of electric mixer for 2½ minutes. Add egg, remaining milk, and vanilla. Beat at medium speed for 3 minutes more. Pour batter into greased 5X5-inch pan. Follow assignment directions for freezing or baking.

Preparation Day:

1. Prepare a double recipe of the spice cake recipe. Pour equal weights of batter into each of two prepared pans. Wrap, label, and freeze one pan of batter. Bake remaining pan of batter at 350oF for 20-25 minutes. Cool, wrap in plastic wrap and foil, label, and freeze.

Evaluation Day:

1. Place frozen batter in refrigerator overnight. Unwrap and bake batter at 350°F for 20-25 minutes.
2. Prepare one recipe spice cake. Pour into baking pan identical to those for the frozen samples. Bake at 350°F for 20-25 minutes; cool.
3. Warm frozen baked cake in heat-proof wrapping in a 300°F oven until heated throughout, about 15-25 minutes.

Observations and Explanations

Spice Cake Characteristics	Fresh Cake	Cake Baked Before Freezing	Batter Frozen Before Freezing
Height of Center Slice
Appearance
Grain
Flavor
Mouthfeel
Conclusions

Freezing Prepared Foods – Egg Salad

Egg Salad

2 eggs	2 tbsp. mayonnaise
2 tsp. chopped green pepper	salt and pepper

Prepare hard-cooked eggs: Add egg to enough cold water to come at least 1” above egg. Bring to boil. Cover pan; remove from heat. Let egg stand in water 15-20 minutes. Cool immediately in ice water. When egg is cold, remove from shell. Chill. Chop eggs for salad. Combine eggs, green pepper, mayonnaise, and seasonings.

Preparation Day:

1. Prepare one recipe egg salad.
2. Pack in a quart-size labeled plastic freezer bag; exhaust air and fasten securely.
3. Freeze immediately.

Evaluation Day:

1. Thaw frozen sample of egg salad.
2. Prepare a fresh sample of egg salad.
3. Compare the two products. Note especially the effect of freezing on the egg white, the mayonnaise, and the green pepper.
4. Record observations regarding freezing mixtures containing cooked egg whites and/or mayonnaise.

Characteristics of the Standard Product for Egg Salad:

• Egg white should be firm yet tender.
• Egg should have a mild egg flavor.
• Mayonnaise should be a smooth emulsion.
• Green pepper should be comparable to fresh sample.

Observations and Explanations

	Appearance	Texture	Flavor
Fresh Egg Salad
Frozen Egg Salad

Freezing Prepared Foods – Ground Meat Patties

Preparation Day:

1. Raw: Shape two patties using ¼ pound ground beef for each. Wrap tightly in plastic wrap and foil. Label and freeze.
2. Shape two beef patties using ¼ pound ground beef for each. Panfry to internal temperature of 165°F. Wrap tightly in plastic wrap and foil (recommended method). Label and freeze.
3. Shape two beef patties using ¼ pound ground beef for each. Panfry to internal temperature of 165°F. Wrap in non-freezer plastic wrap or bag (not recommended method). Label and freeze.

Evaluation Day:

1. Fresh: Shape two beef patties using ¼ pound ground beef for each. Panfry to an internal temperature of 165°F.
2. Panfry raw, stored patties to an internal temperature of 165°F.
3. Reheat cooked, stored patties to an internal temperature of 165°F.
   1. recommended method – 2 patties
   2. non-freezer plastic wrap – 2 patties

Observations and Explanations

	Appearance	Flavor	Texture
Fresh
Cooked after freezing, recommended packaging
Cooked before freezing, recommended package
Cooked before freezing, non-freezer plastic wrap