Understanding Food

Chapter 12: Cheese

Classification of Cheeses

They can be They can be defined by their: defined by their: Microbial Microbial

characteristicscharacteristics AppearanceAppearance Mode of Mode of

packagingpackaging Place of origin Place of origin

The most common The most common ways of classifying ways of classifying cheeses are by the:cheeses are by the: Processing Processing

methodmethod Milk source (cow, Milk source (cow,

sheep, goat, sheep, goat, etc.)etc.)

Moisture content Moisture content

Classification of Cheeses

Cheeses classified Cheeses classified according to their according to their moisture content: moisture content:

FreshFresh.. Moisture Moisture content is over 80%, content is over 80%, and they are not and they are not aged.aged.

Soft.Soft. Water content Water content ranges from 50 to ranges from 50 to 75% and are aged 75% and are aged for just a short time..for just a short time..

Semi-hard.Semi-hard. 40 to 40 to 50% moisture. 50% moisture. Hard.Hard. The moisture The moisture content ranges from content ranges from 30 to 40%. Cheddar 30 to 40%. Cheddar and Swiss are and Swiss are examples.examples.

Very hard.Very hard. Water Water content of content of approximately 30% approximately 30% and are aged the and are aged the longest.. longest..

Cheese Production

No two cheese No two cheese varieties are varieties are produced by produced by exactly the same exactly the same method, but the method, but the basic steps basic steps common to them common to them all include: all include: Milk selectionMilk selection CoagulationCoagulation Curd treatmentCurd treatment

CuringCuring Ripening Ripening

The yield from 10 The yield from 10 pounds of milk is pounds of milk is approximately 1 approximately 1 pound of cheese and pound of cheese and 9 pounds of whey.9 pounds of whey.

Cheese Production

Milk selection has the greatest Milk selection has the greatest influence on classification of influence on classification of cheese.cheese.

Any mammal’s milk can be made Any mammal’s milk can be made into cheese.into cheese.

Cheese Production

Cheese-making starts Cheese-making starts with the coagulation of with the coagulation of the casein protein in the casein protein in milk. milk.

The type of method The type of method used determines many used determines many of the characteristics of the characteristics of the resulting of the resulting cheese. cheese.

The two main methods The two main methods to aid coagulation are to aid coagulation are the action of: the action of: EnzymesEnzymes AcidAcid

Cheese Production

The curd The curd produced by produced by acid has a soft acid has a soft and spongy and spongy texture. texture.

This texture is This texture is influenced by influenced by pH, becoming pH, becoming more solid and more solid and compact as the compact as the acidity acidity increases.increases.

Cheese Production

The curd may be The curd may be treated to remove treated to remove more whey by:more whey by: Cutting Cutting HeatingHeating Salting Salting Further optional Further optional

treatment treatment includes knitting includes knitting and/or pressingand/or pressing

Cheese Production

Curing: Curing: To expose cheese to controlled To expose cheese to controlled temperature and humidity during aging.temperature and humidity during aging.

Ripening:Ripening: The chemical and physical The chemical and physical changes that occur during the curing changes that occur during the curing period.period.

Cheese Production

Processed cheese:Processed cheese: A cheese made from A cheese made from blending one or more varieties of cheese, with blending one or more varieties of cheese, with or without heat, and mixing it with other or without heat, and mixing it with other ingredients.ingredients.

Purchasing Cheese

GradingGrading USDA-defined U.S. USDA-defined U.S.

Grades AA, A, B, and Grades AA, A, B, and C. C.

Graded cheeses are Graded cheeses are evaluated based on evaluated based on their:their: Variety Variety FlavorFlavor Texture Texture Finish Finish ColorColor AppearanceAppearance

Exceptions to these Exceptions to these

criteria are:criteria are:

Colby cheese, in Colby cheese, in

which color is not which color is not

considered. considered.

Swiss cheese, which Swiss cheese, which

is graded additionally is graded additionally

for its salt level and for its salt level and

eyes (holes).eyes (holes).

Food Preparation with Cheese

Cheese is most often Cheese is most often used as an used as an ingredient to add:ingredient to add: FlavorFlavor ColorColor TextureTexture

……in a variety of in a variety of ways—on pizza, in a ways—on pizza, in a taco, etc.taco, etc.

The two most The two most important important principles when principles when preparing foods preparing foods with cheese are:with cheese are: Select the best Select the best

cheese. cheese. Keep Keep

temperatures temperatures low and low and heating times heating times short.short.

Food Preparation with Cheese

Selecting a Selecting a CheeseCheese

The chemical The chemical composition of a composition of a cheese cheese determines its determines its functional functional properties and properties and dictates how it dictates how it will be used in will be used in food preparationfood preparation. .

Some of these Some of these functional properties functional properties include:include: ShredabilityShredability MeltabilityMeltability Oiling off Oiling off BlisteringBlistering BrowningBrowning StrechabilityStrechability

Storage of Cheese

Cheese must be Cheese must be stored properly to stored properly to prevent prevent deterioration. deterioration.

Most cheeses Most cheeses should be should be refrigerated.refrigerated.

Some can even Some can even be frozen. be frozen.

Processed cheese Processed cheese products can be products can be stored in a cool, stored in a cool, preferably dark, preferably dark, cupboard until cupboard until ready for use...ready for use... Though Though

refrigeration refrigeration more effectively more effectively retains desirable retains desirable qualities.qualities.

Understanding Food

Chapter 13: Eggs

Composition of Eggs

Just a few examples Just a few examples of how eggs are of how eggs are used in food used in food preparation:preparation:

Structure Structure Thickening Thickening ColorColor Emulsifying Emulsifying

Leavening Leavening Binding Binding Coating Coating Glazing Glazing ClarifyingClarifying

Composition of Eggs

The egg has five major The egg has five major components:components: YolkYolk Albumen (egg white) Albumen (egg white) Shell membranesShell membranes Air cellAir cell Shell Shell

Composition of Eggs

Chalaza (pl. chalazae):Chalaza (pl. chalazae): The ropy, The ropy, twisted strands of albumen that anchor twisted strands of albumen that anchor the yolk to the center of the thick egg the yolk to the center of the thick egg white. white.

Vitelline membrane:Vitelline membrane: The membrane The membrane surrounding the egg yolk and attached surrounding the egg yolk and attached to the chalazae. to the chalazae.

Cuticle (bloom):Cuticle (bloom): A waxy coating on an A waxy coating on an eggshell that seals the pores from eggshell that seals the pores from bacterial contamination and moisture bacterial contamination and moisture loss.loss.

Composition of Eggs

Purchasing Eggs

InspectionInspection The Egg Products Inspection Act of The Egg Products Inspection Act of

1970 requires that egg processing 1970 requires that egg processing plants be inspected and that their eggs plants be inspected and that their eggs and egg products be: and egg products be: WholesomeWholesome UnadulteratedUnadulterated Truthfully labeledTruthfully labeled

Purchasing Eggs

GradingGrading The best-quality eggs are graded The best-quality eggs are graded

USDA Grade AA, followed by USDA USDA Grade AA, followed by USDA Grade A.Grade A.

USDA Grade B, the lowest grade. USDA Grade B, the lowest grade.

Purchasing Eggs

Candling:Candling: A A method of method of determining determining egg quality egg quality based on based on observing observing eggs against eggs against a light.a light.

Purchasing Eggs

Haugh Units Haugh Units The freshness of an The freshness of an

egg can be detected egg can be detected by cracking it open by cracking it open onto a flat surface onto a flat surface and looking at the and looking at the height of its thick height of its thick albumen. albumen.

Fresh egg whites sit Fresh egg whites sit up tall and firm, up tall and firm, while older ones while older ones tend to spread out.tend to spread out.

Purchasing Eggs

Sizing is not related to grading in any way.Sizing is not related to grading in any way. Eggs are sold in cartons by various sizes determined Eggs are sold in cartons by various sizes determined

by a minimum weight for a dozen eggs in their shell.by a minimum weight for a dozen eggs in their shell.

Purchasing Eggs

Functions of Eggs in Foods

Eggs are often combined with other Eggs are often combined with other ingredients. ingredients.

Their unique ability to:Their unique ability to: FlavorFlavor Color Color Emulsify Emulsify Thicken Thicken Bind Bind Foam Foam InterfereInterfere Clarify Clarify

……makes them nearly indispensable in makes them nearly indispensable in cooking. cooking.

Functions of Eggs in Foods

Clarify:Clarify: To make To make or become clear or become clear or pure.or pure.

Preparation of Eggs

Changes in Prepared EggsChanges in Prepared Eggs The key to cooking eggs is to keep The key to cooking eggs is to keep

the temperature low and/or the the temperature low and/or the cooking time short.cooking time short.

Egg whites and yolks coagulate at Egg whites and yolks coagulate at different temperatures.different temperatures.

Preparation of Eggs

Dry-heat preparation of eggs Dry-heat preparation of eggs primarily involves frying and primarily involves frying and baking. baking.

Egg dishes that are commonly Egg dishes that are commonly fried are fried eggs, scrambled fried are fried eggs, scrambled eggs, and omelets.eggs, and omelets.

Preparation of Eggs

Moist-Heat PreparationMoist-Heat Preparation Eggs can be prepared by moist heat using a Eggs can be prepared by moist heat using a

variety of methods.variety of methods. Most common among these are:Most common among these are:

““Boiled” eggsBoiled” eggs Coddled eggs prepared in a cupCoddled eggs prepared in a cup Poached eggs Poached eggs A variety of custardsA variety of custards Eggs that are prepared using the Eggs that are prepared using the

microwave microwave In all cases, eggs are cooked at simmering In all cases, eggs are cooked at simmering

temperatures.temperatures.

Preparation of Eggs

Hard or Soft Hard or Soft “Boiled”“Boiled”

Hot-Start Method:Hot-Start Method: Soft: 3 to 4 Soft: 3 to 4

minutesminutes Medium: 5 to 7 Medium: 5 to 7

minutesminutes Hard: 12 to 15 Hard: 12 to 15

minutesminutes

Cold-Start Cold-Start Method:Method: Soft: 1 minuteSoft: 1 minute Medium: 3 to 5 Medium: 3 to 5

minutesminutes Hard: 10 minutesHard: 10 minutes

Preparation of Eggs

Microwaving Microwaving Eggs cook extremely rapidly in a Eggs cook extremely rapidly in a

microwave oven. microwave oven. Special caution should be taken to Special caution should be taken to

avoid overcooking.avoid overcooking. Manufacturer’s instructions should be Manufacturer’s instructions should be

followed for microwave egg cooking.followed for microwave egg cooking.

Storage of Eggs

Eggs begin to deteriorate as soon Eggs begin to deteriorate as soon as they are laid and lose quality as they are laid and lose quality very rapidly at room temperature. very rapidly at room temperature.

An egg will age more in one day at An egg will age more in one day at room temperature than in one room temperature than in one week in the refrigerator. week in the refrigerator.

Storage of Eggs

The size of an egg’s air cell provides another indication The size of an egg’s air cell provides another indication of its ageof its age..

Storage of Eggs

FrozenFrozen Freezing a whole egg is not possible Freezing a whole egg is not possible

because it will crack under the expanding because it will crack under the expanding liquids.liquids.

Food manufacturers solve this dilemma by Food manufacturers solve this dilemma by breaking the eggs open at the processing breaking the eggs open at the processing plants where the contents are frozenplants where the contents are frozen Whole (whites and yolk mixed together) Whole (whites and yolk mixed together) Separated as whites or yolksSeparated as whites or yolks

Storage of Eggs

Safety TipsSafety Tips The chances of an egg being The chances of an egg being

internally contaminated are internally contaminated are relatively low, less than one in relatively low, less than one in 10,000 commercial eggs.10,000 commercial eggs.

It is more common for contamination It is more common for contamination to occur during handling and to occur during handling and preparation after the egg has been preparation after the egg has been removed from its shell.removed from its shell.