knh404 exam 2

During rigor mortis, the pH of the carcass: a)Rises abruptly to 9.0 before dropping b)Rises as sodium carbonate forms c)Drops as lactic acid forms from glycogen d)Drops as glycogen is formed from lactic acid

c)Drops as lactic acid forms from glycogen

The tendency of dried milk to become crystalline is due to: a)Sucrose b)Lactose c)Palmitoleic acid d)Phospholipids

b)Lactose

A flaky pastry results when: a)Gluten formation is inhibited b)Steam separates layers of dough c)Oils are used instead of solid fat d)Soft wheat flour is used

b)Steam separates layers of dough

Meat that is cooked while the carcass is in rigor would be: a)Dry b)Tough c)Juicy d)Tender

b)Tough

The sac surrounding the yolk of an egg is called the a)Latebra b)Vitelline membrane c)Chalazae d)Egg white

b)Vitelline membrane

Whole cow's milk is approximately: a)60% water b)72% water c)88% water d)95% water

c)88% water

Two proteins in gluten are: a)Amylopectin and amylose b)Gliadin and avidin c)Gliadin and glutenin d)Ferritin and glutenin

c)Gliadin and glutenin

A muffin with a peaked top has been a)Mixed just right b)Mixed too little c)Mixed too much d)Made with too little sugar

c)Mixed too much

The hormone that can increase milk production in cows is a)Casein b)Whey c)rBST d)None of these.

c)rBST

Triticale is the flour resulting from the cross-breeding of a)Rye and oats b)Oats and barley c)Barley and rye d)Wheat and oats e)Rye and wheat

e)Rye and wheat

isoelectric point

pH when an acid is electrically neutral, makes curds

The addition of baking soda promotes stability of egg white foams. a)True b)False

b)False

Connective tissue

-Binds muscle fibers -Forms ligaments and tendons -Is made up of protein and mucopolysaccharides (a type of polysaccharide)

Secondary structure

-Held together by weaker bonds, such as H -May be in alpha-helix, beta-pleated sheet, or random coil

three common parts of amino acids

-a central carbon atom bonded to a hydrogen atom -a nitrogen-containing amino group (-NH2) -a carboxylic acid group (-COOH)

The changes that occur in collagen during heating result in increased tenderness, while changes in muscle protein during heating reduce tenderness of meat. True False

True

The two major categories of proteins in muscles are: Lactalbumen and lactoglobin Collagen and elastin Actin and myosin Myoglobin and oxymyoglobin

Actin and myosin

A cake that is cracked and peaked and quite brown on the sides has been: Made with too little sugar Baked at too high a temperature Baked at too low a temperature Made with too little baking powder

Baked at too high a temperature

When using self-rising flour in place of all-purpose flour, the ingredients that need to be deleted or reduced are Baking powder and salt Sugar and salt Baking powder and sugar Baking powder and eggs

Baking powder and salt

What factors influence the stability of an egg white foam? Explain the effect of each factor.

Beating technique, temperature, careful separation of yolks and whites, additives, and type of bowl are all factors that influence the stability of egg white foam. The type of eggs that are best to use when making a foam are fresh eggs since they have thick eggs whites, which will result in a more stable foam. The beating technique used should be moderately slow and then when once the egg whites are half whipped speed of whipping should increase. Once whipped completely the egg whites should form stiff peaks. The temperature of the eggs and bowl should be at room temperature because eggs have less surface tension compared to when they are cold, which allows them to be more easily beaten. Some additives that increase the stability of egg white foam are sugar and acid. Sugar should be added at the end of whipping time so volume is not compromised. Acidic ingredients help lower the pH and allow egg whites to whip more easily. Some additives that reduce the stability of egg white foam are salt, liquid, and yolk.

Why do cakes get hard and cookies get soft? Thinking about the concentration of ingredients in these baked products helps to explain how they age.

Cakes tend to go hard if left out because they begin to experience starch retrogradation. The amylopectin reverts back to its original crystalline granules and the baked product losses moisture in the crumb and becomes more rigid. Since cakes have a higher moisture content more water can be lost and make the product staler. This is why cookies get softer when left out since they have a smaller proportion of water compared to cakes and a higher ratio of sugar and fat. When left out the cookies begin to absorb more moisture, making them go soft.

Distinguish between casein and whey proteins, including factors affecting the stability of each

Casein is 80% of the protein found in milk while whey is 20% of the protein found in milk. Casein is a group of 4 similar proteins which can be separated from other milk proteins at its isoelectric point, which is a pH of 4.6. The caseins aggregate at this pH. In milk caseins are dispersed in a suspension throughout the milk by micelles. When acid is added to milk casein precipitates and when rennin is added it results in the formation of a curd. Whey includes lactalbumins and lactoglobulins. Whey is smaller and more compact compared to casein, and is more hydrated. Whey becomes denatured by heat instead of acid like casein.

Fat in a baked product promotes tenderness by: Binding water that otherwise would be free to promote gluten development Coating the gluten strands to retard gluten development Promoting gelatinization of the starch Tying up the egg proteins so they do not interfere with gluten development

Coating the gluten strands to retard gluten development

The protein that may affect tenderness if cooked with moist heat for a long time is: Elastin Myosin Actin Collagen

Collagen

The pigment denatured globin hemichrome is a grayish brown color formed in meat with: Cooking Refrigerator storage Improper wrapping for storage Reduction of iron to the ferrous state

Cooking

Peptide bonds

Covalent bond formed between nitrogen of one amino acid and the C of the carboxyl group of another amino acid

Primary structure

Covalently bonded linear form

The change in the native state of a protein caused by heat is called Denaturation Curdling Hydrolysis Precipitation

Denaturation

Define the following terms (be specific) and give an example of where each occurs. Denaturation Coagulation Curdling

Denaturation is a change in structure of a protein that can be caused by heat, pH change, agitation, and UV light. During the process of denaturation, a protein changes from its tertiary structure to a form more closely resembling its secondary structure due to relaxation. The twisted molecules relax into their elongated form. Desaturated proteins then become less soluble and lose their functional properties. Denaturation can then result to coagulation. Once the molecules are in their elongated form the molecules can then align themselves in clumps through hydrogen bonding. Some factors that affect coagulation are heating, beating, change in pH, and the use of sugar and salt. Curdling happens beyond denaturation and coagulation and is very undesirable. Cuddling causes a product to shrink and become tough. An example where denaturation, coagulation, and curdling happens is the process of cooking eggs. The beating of egg whites causes the egg proteins to become denatured and then they coagulate back together when cooked. When the eggs are cooked beyond coagulation curdling happens and the eggs become tough.

Oven spring in the early part of bread baking is the result of: Explosion of baking powder Increased production of carbon dioxide Expansion of carbon dioxide and/or other gases Death of yeast

Expansion of carbon dioxide and/or other gases

Cake flour contains more gluten forming proteins than bread flour. True False

False

Careful attention to sanitation during storage and handling of eggs prevents infection with Salmonella enteritidis. True False

False

Certified raw milk is safe to drink because careful inspections mean that no dangerous organisms are present. True False

False

Meat is packaged in an oxygen permeable wrap that preserves the bright red color of metmyoglobin. True False

False

The change occurring in elastin during braising is of much practical significance in tenderizing meat. True False

False

Briefly explain the roles of each of the following in baked products: flour, liquid, eggs, fats, sugar, salt, and leavening agents.

In baked products flour provides structure to baked goods because of its protein and starch components. Starch gelatinizes and makes the crumbs more rigid. Liquid hydrates the flour in the mixture and allows for gluten formation. The liquid can also activate the yeast and create some steam for leavening. Eggs contribute to the structure of the finished product and reduce tenderness. Eggs also act as emulsifiers in batters and provide color and flavor to a product. Fats make a product tender, flakey, contribute to flavor, and help prevent the staling process of baked products. Sugar makes a product tender because the sugar in a recipe absorbs the water, which makes less water available for gluten formation and starch gelatinization. Sugar also contributes to volume, flavor, and color. Salt provides flavor and controls yeast growth. Leavening agents become incorporated into a structure and form gases, which contributes to baked goods structure.

One of the problems caused by using honey in place of sugar in a cake is that honey causes: Increased browning and a more acidic batter Increased browning and an increase in pH Limited browning due to reduction in pH The cake to fall

Increased browning and a more acidic batter

Hydrolysis

Increased solubility and decrease thickening ability

As eggs deteriorate, the pH of the egg white Denatures Disappears Is lowered Is raised

Is raised

The following is a characteristic of a high-quality fresh egg: Large proportion of thick white Wide, flat yolk Large air cell Off-centered yolk

Large proportion of thick white

A particularly important emulsifying agent in egg yolk is: Ovalbumin Avidin Vitelline Lecithin

Lecithin

Compare the efficacy of each of the following in tenderizing steaks. Note also any other differences between treatment that would influence consumer acceptance.

Mechanical methods such as grinding or pounding physically breaks down the muscle cells and does not produce a mushy texture sometime found in cuts tenderized by enzymes. This method also makes the meat easier to chew. Meat tenderizer sprinkled on the surface makes it so that the enzymes will only tenderize the surface of the meat due to the limited penetrating properties enzymes have. Meat tenderizer perforated into the meat allows for the enzyme to reach more deeply. The perforation helps carry the enzymes onto the interior of the meat so more of the meat becomes tenderized. Acid marinade ingredients can provide flavor and break down the outside surface of the meat. Some ingredients can be wine, lemon juice, and tomato juice. Fresh pineapple juice on the surface is made up of the enzyme bromelain which is not active at room temperature and reached only during heating. Uniform distribution of this enzyme is important and using too much can cause the meat to have an unappetizing texture.

At the isoelectric point, the neutral nature of the molecule makes a protein have: No pH The ability to form very stable emulsions Minimum solubility Maximum solubility

Minimum solubility

When preparing meat, what ultimately will determine whether you use a dry- or moist-heat cookery method? Give examples of a few cuts of meat that work with moist-heat and others that are better for dry-heat cooking methods.

Moist heat cooking uses water or liquid to convert collagen to gelatin to make meats more tender during the cooking process. Moist heating methods are good for less tender cuts of meat, such as over exercised muscles or muscles from older animals. Some specific cuts of meat that are less tender are beef top round, pork, and lamb, which would all be good options for moist heat cooking. Some types of moist heat cooking are braising, stewing, steaming, and pressure cooking. Dry heat cooking is good for tender cuts of meat, like beef tenderloin and T-bone steak, since they have less collagen and the methods do not have any tenderizing effect. Dry heat techniques use hot air or fat to transfer heat to the meat and results in a rich flavor. Some examples of dry heat cooking methods are roasting, broiling, and frying.

The primary structure of a protein is broken during denaturation. a)True b)False

b)False

If your pastry recipe called for hydrogenated fat and you wanted to substitute butter, you would use: Less butter, since it is not as plastic as hydrogenated fat It is not desirable to substitute butter for hydrogenated fat More butter as it is only 80% fat Same amount of butter since fat is fat

More butter as it is only 80% fat

Tertiary structure

More complex proteins; form by which many occur in nature

In most cakes, air is responsible during baking for : A large portion of the increasing volume Only a small portion of the increasing volume About half of the increasing volume None of the increasing volume

Only a small portion of the increasing volume

The most abundant protein in egg white is: Ovomucin Avidin Ovalbumin Conalbumen

Ovalbumin

The fat globule membrane contains: Lactose and sucrose Phospholipids only Lactose and proteins Phospholipids and proteins

Phospholipids and proteins

The fibrous nature of collagen is due to the comparatively large amounts of: None of these. Methionine and tryptophan Proline and hydroxyproline Leucine and isoleucine

Proline and hydroxyproline

Quaternary structure

Protein consisting of more than one amino acid chain

Just as in cooking red meat, cooking poultry to a high internal temperature results in less juicy meat. a)Ture b)False

a)Ture

What is rigor mortis? How does it affect the tenderness of meat? Describe the changes that occur in meat during aging.

Rigor mortis is the temporary rigidity of muscles that develops after the death of an animal. The muscles stiffen and become hard due to the loss of extensibility of actin and myosin proteins. When the energy reserves become nonexistent the oxygen does not reach the cells. Some water gets forced out of the meat making the meat less moist which can affect the overall juiciness and tenderness of the product. During the aging period many measures are taken to make sure that the meat doesn't become too dry or microbiologically unsafe. Some of these factors that are controlled are the growth of microorganisms through ultraviolet light, controlled humidity, and temperature just above freezing. All of these factors help the meat reach maximum tenderness. Also during aging some linkages between actin and myosin are broken down by proteolytic enzymes.

UHT milk storage is safely done at: Only in the refrigerator Preferably in the freezer Room temperature Room temperature before opening and refrigerated after opening

Room temperature before opening and refrigerated after opening

The type of yeast used for making bread dough is: Saccharomyces cerevisiae Escherichia coli Brewer's Trichinella spirali

Saccharomyces cerevisiae

What factors influence the volume achieved in an egg white foam? Explain the effect of each factor.

Some factors that affect the volume of an egg white foam are beating, temperature, and additives. Beating beyond stiff peaks results in dry foam that has a smaller volume. The bowl, beater, and eggs should all be at room temperature since that will allow for decreased surface tension which makes the egg whites whip more easily and create more volume. One additive that increases the volume and tenderness of the foam is water. Other additives that decrease the volume of a foam are acid, sugar, salt, and fat.

Explain the changes in beef as it is roasted to a medium rare degree of doneness. Include color, tenderness, flavor, muscle proteins, connective tissue, and fat in the discussion.

The roasting of meat uses dry heat and is good for tender cuts of meats because of their reduced collagen and high proportion of muscle protein. Roasting results in a rich flavor from browning and caramelization of surface sugars. Roasting does not have a tenderizing effect so meats should be naturally tender, which means they should have less connective tissue, if being cooked by this method. The roasting of the meat will turn its color to a brighter red because of the formation of oxymyoglobin from heating. During the roasting of beef water is lost and fat begins to melt and protein becomes denatured. Some bound water gets converted to free water, which causes the meat to remain juicy. The water binding capacity of the meat is reduced, which offsets the water that is lost and the muscle proteins shrink.

Meat that is cooked while the carcass is in rigor would be: Tough Juicy Tender Dry

Tough

Lowering the pH of fresh milk from 6.6 to between 4.6 and 5.2 will cause precipitation of casein. True False

True

Sugar and fat tenderize gluten. True False

True

Yeast breads require more time to prepare than quick breads because CO2 needs to be produced in the dough. a)True b)False

a)True

A consumer made biscuits from scratch. Early that morning s/he discovered that they had no baking powder. So they substituted baking soda alone. What were the crust appearance, crumb appearance, and flavor of the biscuits?

When used alone baking soda reacts rapidly with heat and the Co2 may escape from the batter before it has had the chance to leaven. Using baking soda alone will produce sodium carbonate in the product since there is no acid present. This causes the product to have a soapy flavor, poor volume, spotty brown color, and a yellowing of the flavonoid pigment.

Enzymes sprinkled on the surface of meat cause some tenderizing: a)On the surface only b)On the interior only c)Throughout the cut, immediately d)Throughout the cut, only after 12 hours

a)On the surface only

The shelf life of baking powders is promoted by the inclusion of: a)Starch b)Sugar c)Salt d)None of these

a)Starch

ATP catalyzes formation of actomyosin from actin and myosin in muscle tissue. a)True b)False

a)True

Air can be incorporated into batters through creaming fat and sugar, beating after adding eggs, and through beating egg whites. a)True b)False

a)True

Because enzymes are proteins, heat must be controlled to prevent denaturing the protein and halting its enzymatic function. a)True b)False

a)True

During denaturation and coagulation, the tertiary structure of proteins usually is modified. a)True b)False

a)True

Fish fibers are called myotomes which are connected to sheets of connective tissue (mycomatta). a)True b)False

a)True

If two cakes are made using the same formula except that one cake contains somewhat more sugar, the cake with the larger volume will be the one made with more sugar. a)True b)False

a)True

Proteins can undergo a shortening of their primary structure due to acid hydrolysis. a)True b)False

a)True

Ripened cheeses blend into sauces more readily than do unripened natural cheeses. a)True b)False

a)True

S. cerevisiae is the type of yeast used as a leavening agent because it produces carbon dioxide from glucose. a)True b)False

a)True

Starch contributes to the structure of baked products. a)True b)False

a)True

The gelatinous material that collects in the pan when pot roast has been braised for a long time is comparable to the gelatin used in making gelatin gels. a)True b)False

a)True

UHT milk does not have to be refrigerated until it has been opened. a)True b)False

a)True

When using the "muffin method" to prepare quick breads, approximately how many strokes should you use when mixing the wet and dry ingredients together? a)One b)A few c)10 to 15 d)25 to 30

b)A few

The relationship between collagen and elastin is that both: a)Are carbohydrates b)Are proteins c)React similarly when heated d)None of these

b)Are proteins

A peptide linkage is the same as a hydrogen bond. a)True b)False

b)False

As eggs age, the amount of thick white increases. a)True b)False

b)False

Baking powder and baking soda can be substituted in equal amounts for each other in cakes. a)True b)False

b)False

Biscuits are a type of yeast bread. a)True b)False

b)False

Dry heat meat cookery tenderizes meat. a)True b)False

b)False

Enzymes can precipitate casein by adjusting the pH to the isoelectric point of casein. a)True b)False

b)False

Excessive heating has very little effect on egg-thickened sauces. a)True b)False

b)False

For egg yolk to coagulate, at least some amino acids must be split from the primary structure. a)True b)False

b)False

Gluten is present in most flours except rice flour. a)True b)False

b)False

Grade AA eggs are guaranteed to be better in quality than grade B when purchased. a)True b)False

b)False

Homogenizing increases the amount of fat in milk. a)True b)False

b)False

More gluten can be developed in soft wheat flour than in hard wheat flour. a)True b)False

b)False

Salmonella enteritidis contamination usually occurs during storage of eggs. a)True b)False

b)False

Soymilk is a soy product that has been fermented for as long as 3 years. a)Ture b)False

b)False

Tofu is made by precipitating the proteins in egg whites. a)True b)False

b)False

Milk can be clotted by adding a)Acid b)Rennin c)Lactase d)A and B e)B and C

d)A and B

Drip cooking losses are made up of: a)Actin and myosin b)Collagen and elastin c)Protein and water d)Fat and water

d)Fat and water

The type of protein food with the least connective tissue is: a)Poultry b)Beef c)Pork d)Fish

d)Fish

A cake that is tough and dry has been made with too much: a)Milk b)Fat c)Sugar d)Flour

d)Flour

The first step in preparing unflavored, granular gelatin is to: a)Add boiling water and disperse b)Boil in sugar water c)Gelatinize the gelatin d)Hydrate in cold water

d)Hydrate in cold water

An advantage of egg substitutes is that: a)They can be separated successfully b)Volume is greater in cakes made with substitutes than with fresh eggs c)Aroma and flavor are superior to fresh eggs d)No cholesterol is present

d)No cholesterol is present

If all pastries are made using the same formula, the most tender will be the one made with: a)Butter b)Hydrogenated vegetable shortening c)Lard d)Oil

d)Oil

It is not necessary for meat to stand after forking in meat tenderizer because: a)Circulatory system carries enzyme throughout the carcass b)Too much tenderizing makes meat mushy c)Papain tenderizes meat instantaneously d)Papain is not active at room temperature

d)Papain is not active at room temperature

Processed cheese is a cheese made a)from heated cheddar cheese and blue cheese mixed with other natural ingredients. b)through minimum processing of enzyme-coagulated cheese with or without heat. c)from all-natural cheese that is melted and then remolded. d)by combining different varieties of natural cheese, heating, and adding other ingredients to produce a stable emulsion.

d)by combining different varieties of natural cheese, heating, and adding other ingredients to produce a stable emulsion.

The most abundant proteins in milk curd are casein and lactalbumin lactoglobulin and casein lactalbumin and lactoglobulin αs-casein, β-casein, and κ-casein

αs-casein, β-casein, and κ-casein

Denaturation

■Caused by stress (heat, pH change, agitation, UV light, etc.) ■Does not involve breaking of peptide bonds ■Decreases solubility ■Loss of functional properties

Form stable foams

■Low surface tension ■Increases volume ■Increases stability

Coagulation

■Precipitation of protein as molecules aggregate (physical change, not chemical) ■Caused by heating or beating ■Irreversible