Exam 4 Flashcards
1
Q
What poultry does not require inspection
A
- Game birds: pheasant, wild duck, quail
- Emus and ostriches
- Rabbits
2
Q
How is poultry classified?
A
Age and Sex
3
Q
What are the types of chickens classifications?
A
- Broilers
- Fryers
- Roasters
- Capons
- Cornish game hens
4
Q
What are the types of turkey classifications?
A
- young tom
- young hen
5
Q
How is fat distributed in poultry?
A
- White meat lower in fat distribution through muscle
- Myoglobin (red pigment) content is lower in less exercised areas
- Dark meat usually higher in fat, calories and iron content
6
Q
What is market class?
A
age the bird was slaughtered
7
Q
Why is most poultry slaughtered at a young age?
A
lessens the time for connective tissue to develop so it is more tender
8
Q
Mandatory Inspection of poultry
A
- Wholesome Poultry Products Act of 1968
- USDA Food Safety and Inspection Service
- Must be done before poultry can be inspected for quality
- HACCP guidelines
9
Q
Quality Grading (voluntary)
A
◦ Voluntary and paid by the producer
◦ Determination of relative degree of excellence or value
◦ US Grade A—highest consumer grade
◦ US Grades B and C exist, but used for processed poultry (luncheon meats and hot dogs)
10
Q
US Grade A Poultry Standards
A
o Full-fleshed and meaty (amount of meat on bird)
o Good conformation (normal shape of carcass)
o No disjointed or broken bones (free of blemishes)
o Well developed and well distributed layer of fat under skin (amount and distribution of fat)
o Free of pinfeathers, exposed flesh, and discoloration (free of blemishes)
o (for carcasses only) no missing parts
11
Q
Poultry Grade Shields
A
- USDA grade A – Meaty, uniform
fat, well formed, good, clean
appearance - USDA grade B – Not as meaty
as A, occasional tear in skin,
less attractive than A - USDA grade C – May have cuts,
tears or bruises, moderate
trimming permitted
12
Q
Processed Poultry Grades
A
Grade A boneless poultry products
◦ Rolls, roasts, nuggets
◦ Free of bone, cartilage, tendons, bruises, and blood clots
Grade A frozen poultry products
◦ Free of freezing defects such as dehydration or excess moisture
13
Q
Poultry Terminology
A
- Market Class—age at which poultry is slaughtered
- Type—physical state of
poultry product (Fresh, Frozen, Canned) - Style—reflects the amount of
processing or cleaning of
product (Bone-in, Boneless, skinless, Nuggets, strips)
14
Q
What does type of poultry refer to and what can it refer to?
A
“Type” refers to whether it is:
Fresh
Frozen
Cooked
Sliced
Canned
Dehydrated
15
Q
Styles of Poultry
A
“Style” describes the degree
to which it has been cleaned
or processed:
Live
Dressed (only blood,
feathers, craw removed)
Ready-to-cook
Eviscerate: To
remove the entrails
from the body cavity.
Convenience categories
Types and Styles of Poultry
16
Q
Poultry Labeling - USDA
A
- Fresh poultry: Internal temperature never below 26 F
- Frozen: Temperature at 0 F or below
- Basted or self-basted: Bone-in poultry injected or marinated with a solution containing butter or other edible fat, broth, stock or water plus spices, flavor enhancers, or other approved substances
- Natural: Containing no artificial ingredient or added color and is only minimally processed
17
Q
Market Classes
of Chicken - Broiler/fryer
A
◦ Either sex
◦ ~7-10 weeks of age
◦ 3-5 lb., 50% yield
◦ Soft skin, tender meat, flexible
breastbone
18
Q
Market Classes
of Chicken - Roaster
A
◦ Either sex
◦ Under 12 weeks
◦ 6-8 lb., yield varies
◦ Breastbone less flexible
19
Q
Market Classes
of Chicken - Capon
A
◦ Castrated rooster at a young age
◦ ~4-8 months
◦ 12-14 lb.
20
Q
Market Classes
of Chicken - Stewing chicken (Mature chickens)
A
◦ Usually hen
◦ Greater than 10 months
◦ 2 ½ lb. +
◦ Meat is tough and breastbone less flexible
21
Q
Market Classes
of Chicken - Cornish game hen
A
◦ Hybrid of Cornish hen and White
Plymouth Rock rooster
◦ 5-6 weeks; ~2 lb.
◦ Fed acorns and flower petals to
develop “gamey” flavor
◦ Meat is tender
22
Q
Market Classes
of Turkey - Fryer-roaster
A
◦ Either sex
◦ Under 12 weeks
◦ ~7 lb.
◦ Less commonly sold in markets
23
Q
Market Classes
of Turkey - Young Tom
A
◦ Male
◦ 17-18 weeks
◦ Up to 26 lb.
24
Q
Market Classes
of Turkey - Young Hen
A
◦ Hen
◦ 14-15 weeks
◦ ~14 lb.
25
Methods of Poultry Preparation
Roasting (baked) – dry-heat method
◦ Skin and fat are a barrier to prevent evaporation
Poaching – moist-heat method
◦ Similar to braising (chicken pieces browned in oil/butter)
Grilling or broiling – dry-heat method
◦ Popular for boneless
Oven frying – dry-heat method
◦ Coated in fat and breadcrumb mixture
Deep fat frying – dry-heat method
◦ Breaded, floured, battered and submerged in hot cooking oil
26
How does skin contribute to preparation of poultry
- Skin can be removed before or after preparation. It contributes to flavor and juiciness
- Fat that naturally melts off the bird during heating can be
used to baste the poultry or to create sauces
- Basting adds flavor and helps keep the meat tender and moist
27
Whole Birds – Stuffing vs.
Dressing
If stuffed, prepare just before cooking
◦ Mix dry ingredients with other ingredients (margarine,
onion, egg, etc.)
◦ Heat thoroughly in oven until stuffing reaches a minimum
of 165o F
◦ Remove stuffing from bird immediately after cooking
◦ Store stuffing separately in refrigerator in a shallow pan
Best to prepare carcass (empty) and dressing separately in
oven
28
How to Thaw Frozen Turkey
24 hours of thawing for every 5 pounds of whole turkey
29
Determination of Doneness in Poultry
- Always heated to an internal temperature of 165 F (stuffing much also reach this temp)
- Color changes: Juices turn surface golden brown, from pink to clear
- Touch: Flesh is firm, not soft. Joints loosen (leg, wing will wiggle)
- Overdone—flesh will separate from bone; leg, wing will fall off
30
Refrigerate fresh poultry immediately below . . .
40 F
31
Use fresh poultry within . . .
3 days, or freeze
32
Frozen poultry will keep for . . .
6-12 months
33
Safe Handling of cooked poultry
Use directly from refrigerator within 4 days or freeze for up to 4 months
34
Nutrient composition of poultry
Muscle, connective tissue, fat, bone
35
Value of Eggs in the Human Diet
- Nutritional Value - Source of complete protein
- High biological value (absorbed well by humans)
36
Albumen
- white (56% of egg)
- Fat-free protein
37
Yolk and what it’s made of like what vitamins
- (31% of egg)
- Emulsified fat—phosphatidyl choline (lecithin) + cholesterol
- Fat soluble vitamins (e.g., Vitamins A & D)
- Fe (iron)
- Vitamins A and D (depends on amount of sunlight hen
receives)
38
Use of
Eggs in
Recipes
Emulsifier
Leavener
*As a foam—trapping air in liquid albumen
*Provides some structure to products in coagulated protein (when heated)
Binder or thickener
*Holds meatloaf and casserole recipes together
*Gelling agent in custards and puddings
Flavor and color
*Adds color to eggnog and lemon meringue pie
39
what is the Bloom
- cuticle, waxy covering
- Protects against bacterial
contamination
- Natural bloom (mucin) washed
away; commercial bloom applied
40
What is the shell
- outer covering of egg (12% of
egg weight)
- Porous
- Calcium carbonate
- Color dependent upon breed of
chicken
41
What is the shell membrane
- between shell and
egg white (aka, albumen)
- Air cell forms between inner and outer shell membranes
42
What is the air cell
increases in size as egg ages;
at wide end of egg
43
What is the chalazae
- anchors the yolk
- Twisted strands of albumen
44
What is the albumen
- egg white (58% of egg
weight)
- Constructed of layers differing
in viscosity (thickness)
45
What is the Vitelline membrane
surrounds yolk
46
What is the Germinal disc
Fertilization
47
What is the Yolk
- yellow center (30% of egg
weight)
- Protein
- Emulsified fat
48
Major Albumen Proteins
Ovalbumin (~54% of protein in eggs) - Gels well and easily denatured by heat. Responsible for texture of scrambled
eggs
Ovomucoid (11%) - Responsible for raw egg white texture, Inhibits trypsin
Ovotransferrin (conalbumen) (13%) - Complexes Fe, Antimicrobial
Ovomucin (1.5%) - Responsible for thickness of egg white, Reacts with viruses
Lysozyme (3.5%) - Catabolic enzyme, Antimicrobial, Avidin (0.05%) - Binds B vitamin biotin (raw egg white only)
49
Major Egg Yolk Proteins
Lipoproteins (~3 grams of protein found in egg yolk)
◦ Fat and protein complexes
◦ Useful emulsifying agents
◦ Lipovitellin
◦ Lipovitellinin
50
Egg Inspection
- Mandatory
- Egg Products Inspection Act, 1970, Law enforced by USDA
- "Restricted eggs” not allowed to be sold
51
Egg Quality
- Voluntary
Egg quality is determined by:
1. Candling
2. Measuring Haugh units
3. Evaluating appearance (shell, white,
yolk, air cell)
52
Egg Quality
& Grading
Candling: egg held above 40 watt light source to determine egg quality
◦ Quality of shell
◦ Size of air cell
◦ Positioning of yolk
◦ Presence of blood spots
Egg quality grades
◦ USDA Grade AA
◦ USDA Grade A
◦ USDA Grade B (thinner whites and somewhat flattened yolks)
53
Egg Size
- Grade and size are
unrelated
- Size of egg is based
upon the minimum
weight of a dozen
- Size varies in 3 oz.
increments, from pee
wee to jumbo
54
What are the egg sizes?
- Pee wee: 15oz/dozen
- Small: 18
- Medium: 21
- Large: 24
- X-large: 27
- Jumbo: 30
55
What is the effect of Heat on Eggs?
- Egg whites begin to coagulate at 140 F and completely coagulate at 149-158 F
- Egg yolk coagulates at 144-158 F
- Beaten eggs coagulate at 156 F
- Slow heating permits coagulation at lower end of range, rapid heating raises coagulation temperature to upper end
56
How do added ingredients change egg coagulate temperature?
- Sugar increases temperature of
coagulation to 180 F
- salt/acid lowers it
57
Hot-Start Cooked Egg
◦ Water is boiled, eggs added
◦ Many times the shells will crack
◦ Heat is reduced to “simmer”
and cooked for 3-15 minutes
◦ Soft-cooked— 3 to 4 minutes
◦ Medium cooked — 5 to 7
minutes
◦ Hard-cooked —12 to 15 minutes
58
Cold-Start
Method
◦ Preferred method that reduces
cracked shells
◦ Put eggs into cold water, bring
to boil
◦ Reduce heat at boiling and
cook for
◦ Soft-cooked—1 minute
◦ Medium cooked— 3 to 5 minutes
◦ Hard-cooked —10 minutes
OR
◦ Remove from heat immediately at
boiling and cover tightly
◦ Let stand 20 minutes
59
What are the positive effects of heat on egg protein?
Denaturation
* Smooth texture
* Flavor development of
cooked egg
* Color of cooked egg
Gelation
* Egg protein capable
of gel formation
* Homogeneous semi-rigid product
60
What are the negative effects of heat on egg protein?
All refer to loss of water caused by high heat
Overheated protein (curdling)
◦ Tough, rubbery
◦ Shrinks, giving appearance of curdling
Syneresis, weeping
◦ Escape of liquid from protein caused by
kinkiness of denatured protein
◦ Too much heat causes “tightness” of protein coil, expelling water
Beading
◦ Appearance of tiny droplets on surface of egg mixture
61
What is an Iron Sulfide Ring and what causes it?
- Green ring surrounding egg
yolk, occuring in hard cooked eggs.
- Begins to appear at 155 F
- Most frequent when older
eggs are used
- Encouraged by high heat, rapidly forms at 185 F
62
How do you lessen iron sulfide ring formation?
1. Use fresh eggs
2. Low temperature
3. Dip in cold water after
boiling
63
What type of reaction is heating an egg?
endothermic reaction which is achemical reaction that absorbs heat from its environment
64
How does the heating of an egg work?
- Heat energy is absorbed from the pan to cook the egg and coagulation takes place
- Temperature will remain constant (plateau) while
coagulation is taking place
- Temperature will begin to rise a second time when coagulation is complete
- Important when measuring temperature of stirred
custard
- When temperature rises a second time is the moment to remove mixture from heat
- If heating continues→ curdling
65
What are the methods of egg preperation?
Dry heat:
◦ Baking—similar to roasting in hot oven (Shirred eggs, meringues, soufflés)
◦ Frying—similar to grilling, using 1 tsp. fat per egg in a hot pan
(Sunny side up, over easy, over hard, over medium, scrambled)
Moist heat:
◦ Cooking: (not boiling) simmering (Hard and soft cooked eggs, coddling, poaching, stirred custards)
66
What are factors that influence egg white foam?
1. Beating technique
2. Temperature
3. Type of bowel
4. Careful separation of yolks and whites
5. Whether sugar, fluid, salt or acid are added
67
How does temperature and bowl selection influence egg white foams?
◦ Bowl, beater, and eggs should be at room temperature
◦ Decreased surface tension of room-temp. allows egg whites to whip more easily & have larger volume than cold eggs
◦ Deep bowls w/rounded bottoms are best b/c they
allow egg whites to be picked up by the beater
◦ Plastic bowls should be avoided – may have film or
grease from prior usage due to porous surface
68
How do additives influence egg white foams?
Sugar:
◦ Stabilizes egg white foam but also inhibits coagulation of proteins for foam formation
◦ Best to add sugar near end of whipping
Fluid:
◦ Increases the foam volume up to 40% but decreases its stability
Salt:
◦ Decreases stability and volume of egg-white foam
◦ Rarely added to egg whites
Acid (lemon juice, cream of tartar):
◦ Egg whites tend to be alkaline (pH ~8.4)
◦ In proper amounts, adding acid decreases pH of egg whites, which allows it to whip better into a foam
69
How do you store eggs?
◦ Refrigerate—29-32o F—reduces mold and bacterial growth
◦ Can store for about 1 month fresh (Recommended storage time is 1 week)
70
What are egg substitutes?
◦ Egg yolk contains 200+ mg cholesterol
◦ Egg substitute products contains mostly egg whites
◦ Pasteurized
71
What are value-added eggs?
Hens are fed a modified diet
◦ Lower cholesterol
◦ Higher omega-3 fatty acids
◦ Higher in vitamin E
72
How is marine life classified?
- Vertebrates
- Invertebrates
- Freshwater
- Lean or fatty
73
What makes an animal a vertebrate? Give examples
Also know as finfish, they have fins an internal skeletons.
- tuna
- cod
- salmon
- catfish
- flounder/sole
74
What makes an animal a invertebrate? Give examples
Also known as shellfish, they have external skeletons
- crustaceans (shrimp, crab, lobster, crayfish), covered in a crust-like shell with segmented bodies
- mollusk, posses a soft structure and are fully or partially encases in a hard shell
75
What are examples of freshwater marine life?
catfish, pike, trout
76
What are examples of saltwater marine life?
salmon, cod, flounder, tuna
77
What are examples of lean marine life?
cod, sole
78
What are examples of fatty marine life?
salmon, tuna, whitefish
79
What are the sources of marine life?
- Nondomesticated sources:
oceans, lakes, rivers,
domestic, imported
- Aquaculture: natural or
controlled marine or freshwater environments like fish or shellfish farms
80
In 2021, what were top commerically caught fish?
1. Menhaden AKA "Bunker" 80 million lbs
2. Atlantic Clams 15.6 million lbs
3. Ocean quahog, Clams 11.5 million lbs
4. Blue Crab 4.49 million lbs
5. Sea scallops 4.48 million lbs
81
In 2021, what were top recreationally caught fish?
1. Stripped Bass 8.3lbs million
2. Yellow fin tuna 3.9lbs million
3. Flounder, summer 3.7lbs million
aka "Fluke"
4. Blue fish 3.3lbs million
5. Tautog 2.7lbs million
82
What are the classifications of mollusks? Give examples
1. Bivalve
- clam
- mussel
- oyster
- scallop
2. Univalve
- conch
- snail
- abalone
3. Cephalopod
- octopus
- squid
83
Why is fish tender?
1. Collagen
- Fish muscle has very small amounts of collagen (~3%)
2. Amino Acid Content
- Low amounts of amino acid, hydroxyproline, in its connective tissue
- Breaks down more easily at lower temps and converts to gelatin
3. Muscle Structure
- Shorter muscles arranged into layers of short fibers called myotomes
- Separated by very thin sheets called myocommata
84
What is the composition of fish?
Protein – high protein food
Low in fat and cholesterol
- Rich source of omega-3 fatty acids, EPA and DHA
- Lean finfish and shellfish contain ~5% fat
- Fatty finfish contain a little more fat, 5-10%
Glycogen
- Small amount found in shellfish
Vitamins & Minerals
- Good source of B-vitamins (e.g., niacin, thiamin)
- Vitamins A & D
- Zinc, copper, iron, iodine (salt water), calcium (variable)
- Contaminants?
85
Why do different fish have different color flesh?
White, pink, or red—depending upon the speed the fish required in life
- Red—slow twitch fibers for long distance swimming (e.g., salmon)
- White—fast twitch fibers for quick bursts of speed (e.g., sole)
- Pink—moderate twitch fibers for short distance swimmers
Fat—higher fat content darkens flesh
- Mackerel
- tuna
Myoglobin contributes to the overall color of fish flesh
(increased myoglobin = more oxygen)
86
Explain the inspection & Grading of marine life?
- Voluntary
- Producer can pay to have fish inspected for wholesomeness and sanitary conditions of
processing plant by National Marine Fisheries Service in U.S. Dept. of Commerce
- Quality grades U.S. Grade A, B, or substandard. Based on appearance, texture, flavor, odor, absence of defects, and uniformity
87
How are shellfish shippers certified?
- U.S. Dept. of Commerce
- Monthly publication
- Waters from which shellfish are harvested that are tested and free from contamination
- Wholesale containers of shellfish must be labeled to include harvester's name,
address, and certification number, the date & location of harvest, and the type and quantity of shellfish
- Shucked products must have “sell by date” or “date shucked”
(Foodservice operations required to keep these tags for at least 90 days upon receipt)
88
What are the safe intakes of seafood?
women who may become pregnant, women who are pregnant, nursing mothers, and young children should not consume seafood
Mercury Contamination can accumulate to levels that are toxic to developing central nervous system
Fish most likely to contain mercury: shark, swordfish, king
mackerel, tilefish
89
What seafood should woman who are or may become mothers, pregnant, nursing, and children avoid?
- mackerel
- marlin
- shark
- swordfish
- tilefish
- tuna steak
90
What are some safety issues around seafood?
CDC estimates that ~10% of FBI outbreaks are due to consumption of marine products
Some potential toxins found:
- Scombroid fish poisoning caused by increased histamine
production by microorganisms
- Ciguatera fish poisoning caused by eating reef-feeding
fish that have consumed toxins in the reef
- Paralytic shellfish poisoning is caused by clams, mussels,
and scallops eating toxins in red tide
91
How much fish is consumed?
Estimated U.S. per capita consumption of fish and shellfish
is 15.5 lbs./per person
92
How much fish do DGAs recommend?
8 or more ounces of seafood each week (~26 pounds annually)
93
Factors that can contribute to seafood spoilage are . . .
Proteolytic enzymes break down muscle proteins and provide amino acids for bacterial growth
Bacterial enzymes can also break down proteins to amino acids and elevate the levels of histamine, a toxin
Excessive consumption of this toxin leads to a food borne illness known as scrombroid fish poisoning (e.g., tuna, mahi mahi, bluefish)
- Usually occurs when fish have not been chilled immediately after being caught
94
Examples of very low fat fish
less than 2.5g total fat
- clams
- cod
- mahi mahi
- scallops
- shrimp
- squid
95
Examples of low fat fish
more than 2.5g total fat but less than 5g
- bass
- catfish
- oysters
- salmon(pink)
96
Examples of fatty fish
Moderate is more than 5g but less than 10g
- mackerel (Spanish)
- salmon (Atlantic)
- whitefin
Higher fat is more than 10g
- mackerel (Atlantic)
- Salmon (King)
97
What part of fish spoils first?
Guts and heads
98
What are the market forms of finfish?
Whole or Round
- Whole fish, as caught
Drawn
- Whole fish with entrails (organs) removed
Dressed
- Head, tail, gills, and scales removed in addition to entrails
Steaks
- Cut from dressed fish by slicing from top fin to the bottom fin at a 90 degree angle at varying thickness
- Contain portion of backbone and other bones
Fillets
- Slicing fish lengthwise from front to back to avoid the bones
- Whole boneless side of fish
Sticks
- Uniform portions cut from fillets or steaks
- Minced fish that is shaped, breaded and frozen
99
Tips for purchasing fish:
- Fresh fish should not smell
- For whole or round fish, eyes should be clear, not cloudy, and scales should adhere to skin
- Should have gel
- Pay attention to the environment of the sale of fish
100
What are some popular prepared fish?
Surimi
- Whitefish, usually turbot, flavored, colored red, with added
sugar and salt
- Less costly alternative to crab and lobster
- Labeled seafood on menus
Sashimi
- Raw fish used in preparation of sushi (rice)
- CDC warning for possible contamination of bacteria, viruses, and parasites
101
How is surimi prepared?
1. Fish is minced
2. Washed to remove fat, blood, and pigments, leaving only myofibrillar protein
3. Myofibrillar protein is frozen with cryoprotectants (sucrose and sorbitol or maltodextrin and polydextrose) to protect
integrity of the fish protein
4. Later processed and fiberized to produce the elastic and chewy texture
102
What is the relationship between high moisture content and the doneness of fish.
- high moisture = high evaporative losses
- Dries out quickly
- Avoid moisture loss by wrapping fish in foil, parchment paper, etc. during cooking
- Protein coagulates = hard and chewy
103
What is the type of fish that is not deep fried?
fatty finfish because too much fat is retained = oily, fishy flavor
104
Fish and shellfish are best consumed after . . . of purchase
a day or two
105
Tips for fish and shellfish storage:
- Fish should be stored in the coldest portion of the refrigerator
- Never refrozen once it is thawed
- It should also be tightly wrapped to prevent odors
from coming in contact with other foods
- Canned fish have a shelf life of 12 months
106
What is Osteoporosis?
A condition of gradually
weakening, brittle bones
Bones lose calcium and
other minerals, becoming
more fragile and porous
107
What percentage of Americans fail to meet dairy recommendations?
90%
108
What is the most common source of milk in the US?
Bovine cows (dairy cows)
109
Why is milk almost a perfect food?
complete protein, rich in many B
vitamins, vitamins A and D (when fortified), and calcium
lacks vitamins C & E, iron, and contains no complex CHO or fiber
110
What is supplement is given to dairy cows and why?
Bovine Somatotropin (BST) (recombinant bovine growth hormone)
Improves milk producing efficiency
111
What is pasteurization of milk?
A heating process applied to foods to destroy pathogenic microorganisms
112
Explain low-temperature, longer-time pasteurization.
145 F for 30 minutes
113
Explain high-temperature, short-time pasteurization.
161 F for 15 seconds
114
Explain higher-heat, shorter-time pasteurization.
212 F for 0.01 seconds
115
Explain ultra pasteurization.
280 F for 2 seconds or more (shelf life extended)
116
Why can milk still spoil after pasteurization?
The 1 to 5% nonpathogenic
bacteria remaining can convert lactose to lactic acid.
117
What is the homogenization of milk?
mechanical process that breaks up fat globules in milk into much smaller globules and are permanently dispersed in a very fine emulsions
Milk containing fat is forced under high pressure through a sieve-like opening at 2500 lb/in2 to permanently break up the fat globules
118
What are the characteristics of homogenized milk?
Whiter in color, more viscous, more bland in flavor and foams easily
119
What is the composition of cow's milk?
can vary depending on the breed, stage of lactation, type of feed ingested and season of year
Milk is primarily water (~88%)
Neural pH of 6.6 (ideal for bacterial growth)
Remaining 13% by weight include:
CHO
Fat
Protein
Minerals & Vitamins
120
Carbs in milk
~ 5%
Lactose = disaccharide of glucose + galactose
~12 g per 8 oz. cup
Bacteria metabolize lactose → lactic acid
Creates an acid environment in GI tract which may serve as a basis of
immunity to disease (probiotic)
Acidity in GI enhances absorption of calcium
121
Protein in milk
~3%
Complete protein
8 grams per 8 oz. cup
Casein (80% of protein in milk)
Whey (18% of protein in milk)
122
What are the major proteins in milk?
Casein and whey
123
What is casein protein?
Phosphoprotein
At pH 6.6, the phosphoric acid
part of casein combines with
calcium to form calcium caseinate
Casein micelles and calcium
phosphate salts are responsible
for the white color of milk
Milk protein precipitates at pH 4.6 (curd)
124
What is whey protein?
Lactalbumin and lactoglobin (water soluble proteins)
Adding acid → curd during yogurt and cheese production
Used in food industry as emulsifier, foaming agent and gelling agent
125
What is the minimum amount of butterfat found in legal whole milk in NJ?
3.25%
126
What is milk fat?
Cream
less dense than water
127
What are the major minerals in milk?
calcium and phosphorus
1 - 8 oz. glass of milk contains 300 mg of Ca - DRI for adults = 1000 mg/day
128
What are the major vitamins in milk?
Vitamin D, Vitamin A, riboflavin
129
Is milk inspection mandatory and what is the criteria?
Every dairy farm is inspected and sampled before leaving the farm
Quality milk is produced under rigid sanitary conditions that need to meet specific criteria:
Relatively low bacteria count
Free from disease-producing microorganisms
Good flavor and appearance
High nutritive value and keeping quality
130
MILK GRADING - USDA
Voluntary – paid for by dairy industry
Primarily based upon bacterial content
Most rigid controls on production and processing of
Grade A milk (used by consumers as fluid milk)
- Grade A pasteurized milk may contain 30,000 microorganisms/cc
- Raw milk under very strict local supervision, subject to
more frequent examination
- At delivery, raw milk cannot contain more than 10,000
microorganisms/cc
131
TYPES OF FLUID MILK
Pasteurized, homogenized whole milk
Contains at least 3.25% butterfat
Contains at least 8.25% MSNF (nonfat milk solids)
Optional, but usually contains fortification of vitamins A & D
132
FAT MODIFIED MILK
Reduced fat
2% fat
Low fat
1% fat
Both must contain at least 8.25% MSNF, but if level exceeds 10%, product must be labeled protein fortified
Vitamin A fortification is mandatory, vitamin D is optional
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FAT FREE OR NON-FAT MILK
Removal of as much fat is technically impossible, so what remains is trace or less than 0.5 grams/cup
Contains not less than 8.25% MSNF
Some products use 10% or more MSNF
Vitamin A fortification is mandatory, vitamin D is optional
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ORGANIC MILK
Produced by cows not treated by:
Antibiotics
Growth hormones
Cows eat from pastures that are certified organic (fertilizer and pesticide free)
Dairy herds are free of genetically modified animals and cloning
Some are ultrapasteurized
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FLAVORED MILK
Usually chocolate
1% cocoa + 5% sugar
Chocolate whole milk—optional vitamins A and D
fortification
Chocolate fat free milk—mandatory vitamin fortification
Flavored milk drinks
Read label carefully, milk content of beverage may be <5%
Product may be marketed deceptively, in a refrigerated
gable topped container
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BUTTERMILK
Cultured milk
Liquid left after butter churned
Commercial fat free milk to which a lactic acid culture has been added
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ACIDOPHILUS MILK
(CULTURED MILK)
Lactobacillus acidophilus culture added to milk
Bacteria break down lactose to
glucose and galactose
Used in dietary modification for individuals who cannot tolerate fluid milk
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PROCESSED MILK
Evaporated
Whole or fat free
60% of water evaporated from fluid milk
Sweetened Condensed
Evaporated + 15% sugar added
Used for dessert preparation
Ultrapasteurized—brick pack—milk box
Whole or reduced fat
Dry storage, up to 3 months
Must be refrigerated after opening
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YOGURT (FERMENTED)
Cultured product produced by introducing two microorganisms into milk, lactobacillus bulgaricus and streptococcus thermophilous
Mixture is held from 108 – 115o F to develop the desired
consistency, flavor and acidity
Gelation to form a gel
If chilled following production, yogurt contains active culture
If heated after production, culture is destroyed
May have nonfat dried milk, gelatin, fruit preserves, or
sweetener added
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GREEK YOGURT
Yogurt is strained and pressed to remove whey and lactose
Resulting product is more viscous than other yogurts
6 oz contains 15-20 g protein (double than conventional yogurt)
5-8 g CHO—most lactose is removed (~1/2 the CHO
of conventional yogurt)
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KEFIR
Fermented milk product
Results in bubbles
Milk is cultured with Lactobacillus caucasius and a yeast, Saccharomyces
kefir and Torula kefir
Lactic acid production causes sour taste
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NONFAT DRY MILK
NFDM
Aka powdered, dry milk
All fluid is removed
Vitamins A and D optional
Prepare using label directions and CHILL
May be added to recipes (added to products) to improve nutritional value of the product without noticeably altering flavor or texture
Long shelf life of 1 year in cool, dry storage area
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VALUE-ADDED MILK
Fat free milk in which NFDM added
Improves viscosity (mouthfeel = more “creamy” than fat free milk
Improves nutritional value
~45% more calcium
~35% more protein
Brands
Smart Balance
Skim Plus
Over the Moon
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MILK WITH ALTERED COMPONENTS
Filled milk
MSNF + water + fat (other than milk fat)
Usually a vegetable fat
Nondairy imitation milk
Vegetable oil or fat, corn syrup solids, Na caseinate,
vegetable protein, vitamins, minerals, emulsifiers,
stabilizers, and flavoring agents
Sodium caseinate (protein found in soybeans) is
classified as a nondairy ingredient by federal and state
law
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OTHER MILKS
Lactose-free
Disaccharide lactose hydrolyzed to glucose + galactose by enzymatic action
Easier to digest if person is lactose intolerant
Fiber-enriched
Fat free milk with added fiber (cellulose gel) to improve mouthfeel
Thicker consistency than fat free milk
Enriched with Calcium
Soy (Plant-based)
Made from soybean curd
Almond milk (Plant-based)
Produced from crushed almonds and water
Many other alternative milk varieties (rice, oat, hemp, etc.)
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CREAM
High fat liquid separated from fluid milk by centrifugal force
Heavy
Heavy whip 36-40% butterfat
Light whip 30-36% butterfat
Light
Table, coffee 18-30% butterfat
Sour cream = cultured light cream (lactic acid culture)
Half and half
½ light cream + ½ whole milk = 10-18% fat
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WHIPPING CREAM
Foam is formed
Protein in cream acts as foaming agent which lowers the
surface tension of water, allowing air bubbles to be
trapped
Bubbles are surrounded by a thin film of protein
Foam cells are stabilized by coalesced fat globules
Cold temperature maintains fat globule in solid form (desirable)
Recommended to chill bowl, beaters, and cream when
making whipped cream
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STORAGE OF FLUID MILK & CREAM
Highly perishable
Requires refrigeration, remove just before using
Containers should be closed or covered to avoid rancidity, microbial contamination, and
absorption of odors from other refrigerated foods
Not exposed to sunlight—destroys riboflavin
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EFFECTS OF HEAT ON MILK
Whey
Lactalbumin and lactoglobin precipitate
Collect at the bottom of the pan and will scorch with continued heat
To prevent scorching: stir continuously or use a double boiler
Casein
Surface water evaporates when heating milk, which increased
concentrations of casein, fat, and mineral salts
Creates a film (scum, sheet of protein)
Sheet is resistant to stretching, resulting in boil over
Use low temperature and cover
Flavor
Casein, lactalbumin and lactoglobin denature and result in flavor changes
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ACID ACTIVITY IN MILK
pH of fresh milk is 6.6
At pH 4.6, colloidal dispersion of casein in water becomes
unstable and forms a curd
Sources of acids: lemon and lime juices, tomato products
and certain fruits
Similar occurrence of milk coagulating is obtained when
polyphenolic compounds (tannins) are present →
precipitation of proteins
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ACIDITY OF MILK
Factors that increase acid content of milk
Loss of CO2 in standing
Acid introduced in cooking
Bacterial production
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EFFECT OF ACID ON CASEIN
Curdling
Casein is emulsified in milk by electrostatic forces
+ and – charges of minerals or salts in milk
Change in concentration of either + or – charges by
adding H+ through acid ingredients or bacterial
production will cause the emulsion to break→ curdling
Forms basis of cheese production
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CHEESE
Preserved food made from the curd of milk
Dairy product produced from milk by precipitation of casein
Type of milk varies (e.g., cow, sheep, goat), but most domestic cheeses are produced from cow’s milk
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CLASSIFICATION OF CHEESE
* Milk source
* Fermentation and ripening condition
* Type of bacteria utilized
* Methods of pressing, sizing, and shaping
* Place of origin
Classified usually according to moisture content
* Fresh—cottage, cream cheese ricotta, feta cheese
* Soft—brie, cambert and Hispanic cheeses
* Semi-hard—bleu, muenster, brick, gouda, gorgonzola
* Hard—cheddar, swiss
* Very hard—(grating) parmesan and romano, too hard to slice
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NUTRITIVE VALUE OF CHEESE
Nutrient-dense food
1 oz. = 100kcal (most from fat)
Concentrated source of milk
10 pounds of milk are used to make 1 pound of cheese + 9
pounds of whey
Protein content is identical to protein content of the type
of milk used
Fat is mostly saturated
Contains cholesterol
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CHEESE PRODUCTION
◼ Cheese-making starts with the coagulation of the casein protein in milk
◼ The type of method used determines many of the characteristics of the
resulting cheese
◼ The two main methods to aid coagulation are the action of:
1. Enzymes (rennet, coagulants [from vegetable or bacteria])
2. Acid
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CHEESE PRODUCTION PROCESS
Curing: To expose cheese to controlled temperature
and humidity during aging
Used to improve flavor
Ripening: The chemical and physical changes that
occur during the curing period (vary from 4 weeks to
>2 years)
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What is processed cheese?
A cheese made from blending one or more varieties of cheese, with or without heat, and mixing
it with other ingredients
contains more moisture and
less fat
Must be at least 51% natural cheese by weight
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U.S. GRADES OF CHEESE
USDA-defined U.S. Grades AA, A,
B, and C.
Graded cheeses are evaluated
based on their:
Variety
Flavor
Texture
Finish
Color
Appearance
Exceptions to these criteria are:
Colby cheese, in which color is
not considered.
Swiss cheese, which is graded
additionally for its salt level and
eyes (holes).
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EFFECT OF HEAT ON CHEESE
A hard cheese, like cheddar, softens and melts when heated at low to moderate temperatures
Further heating, and high heat, will result in separation of fat and development of a tough,
rubbery curd, which will form long strings
Protect cheese from overheating
* Divide cheese (grate to increase surface area)
* Add cheese to final stage of heating process
A hard cheese, like cheddar, softens and melts
when heated at low to moderate temperatures
More highly ripened cheese (protein in curd more readily dispersed)→ blends better
Highly emulsified processed cheese—protein is protected by other ingredients → less likely to string
