Test 2 Flashcards
Types of cows that produce milk
Jersey, Guernsey, Brown & Holstein
Other animals that make milk
Buffalo, Camels, Sheep, Goats, Yak, Deer
Milk alternatives
Almond, Rice, Soy, Coconut, Hemp
Cow cycle of birthing
Mother cow gives birth between 1 and 3 years old. Calf nurses for 1 week then calf is fed formula of soy and reconstituted milk. Mother is then milked for 10 months and then given 2 months to rest and then bred again
pH of raw milk
6.5-6.7 (slightly acidic)
Nutrients in raw milk
protein, fat, and carbohydrate, vitamins A, E, D and riboflavin (B2)
What two major proteins are in milk
Whey and casein
Carbohydrate in milk
Lactose which breaks down to glucose and galactose
Fat in milk
Stored as globules, encased by phospholipids
Resilient to heat but not freezing
What percent of milk is casein
80%
What percent of milk is whey
20%
Casein protein
Curdle or coagulate in acids, precipitates out of solution
Whey protein
Remains suspended in liquid with acids
Leftover from cheese making
As pH nears 5.5 what happens to casein
it precipitates out
Health promotion benefits
Manufacturers isolate milk proteins
Add them to products to ↑ nutritional value
Examples of proteins that have been isolated
Milk protein concentrates
Whey protein isolate
Hydrolyzed whey protein
Whey permeate
What does raw milk contain that is valued in cheese making
white blood cells
Mammary gland cells
Bacteria
Active enzymes
Aroma of milk
Short chain fatty acids
Specific to animal
Goat and sheep offer unique fatty acids
Heating/cooking milk
produces sulfur and green leaf aromas
Heating milk above 170 degrees
vanilla, almond, butter
*check in book
Boiling milk
Maillard reactions
Butterscotch flavors
Maillard reactions
a chemical reaction between amino acids and reducing sugars that gives browned foods their desirable flavor
What can also affect aromas and flavor of milk
age
What flavor/aroma does hay and silage give milk
cheese smell
What flavor/aroma does a lush pasture give milk
sweet, fruit smells (raspberry)
Batch pasteurization
(Low temp long time)
145 for 30-35 minutes
High temp, short time pasteurization (HTST)
heated and held at a minimum of 161 degrees F for 15 seconds
Ultra High Temperature (UHT)
Heated to 280 for 2-3 seconds
Packaged under sterile technique, has long shelf life (months without refrigeration)
Some proteins & enzymes destroyed, affecting whipping, cheese production
What is the sterile packaging that ultra high temperature is packaged in
Aseptic packaging
Sterilized milk
Heated to 280-302⁰F for 2-6 seconds
Keeps indefinitely at room temperature
What is the goal of homogenization
Keep fat molecules dispersed
Process of homogenization
Hot milk pumped at high pressure through small nozzles
Fat globules broken from 4 to 1 micrometers
Broken fat globules stick to milk casein
does pasteurization or homogenization occur first
Pasteurization occurs prior to or at same time as homogenization
What percent of whole milk is fat
3.5-4%
What percent of low fat milk is fat
1-2%
What percent of skim milk is fat
.1-.5%
Fortification
Vitamin A and vitamin D added
Acidophius
lactobacillus acidophilus added
Lactaid
milk treated with lactase
Dried or powdered milk
Low fat milk, pasteurized
90% of moisture evaporated, spray dried
Keeps for several months
Concentrated milks
Condensed or evaporated milk: milk heated to 110-140⁰F in vacuum, under pressure
Homogenized and sterilized
Sweetened, condensed : table sugar added (55%)
Plant based milks
Nut Based: Almond or Coconut Milk
Legume Based: Soy Milk
Seed Based: Hemp Milk
Grain Based: Rice or Oat Milk
Example of a nut based milk
almond or coconut milk
Example of a legume based milk
soy milk
Example of a seed based milk
hemp milk
Example of a grain based milk
rice or oat milk
Why scald milk
To kill bacteria (now is done by pasteurization) Destroys enzymes (done via pasteurization now) *Denatures proteins & changes interactions during cooking or baking* ---Would kill wild yeast & bacteria present after pasteurization
What is scalding milk
Skin at top concentrated casein, calcium, whey
Other proteins concentrated at bottom
Negative reactions in cooking milk
- old milk will curdle (in hot coffee/tea)
- Acids & tannins curdle milk
Which fat content milk curdles faster
Low fat milk products
What happens to sweetened condensed milk when its heated
Caramelize in can when heated Maillard browning reaction
Foaming
proteins collect around air pockets
What types of milk make better foams
skim and low fat milks as well as cold milk
milk foaming process
Steam nozzle pushes bubbles into milk
Heats the bubbles
–unfolds and coagulates whey proteins
Works most efficiently with nozzle just below surface
Cream
High fat content
–Concentration of fat to protein (10:1)
Cream pasteurization
Pasteurized after separation from milk
–Ultrapasteruized: 2 seconds @280°F/140°C
Cream is less likely to curdle in cooking (T/F)
True
Does cream spoil quicker than butter?
yes
Half and half fat content
12%
Light cream fat content
20%
Light whipping cream content
30-36%
Whipping cream content
35% +
Heavy whipping cream fat content
38%
Lighter creams
- poured in coffee, over fruit
- Lower fat cannot stabilize foam as well as higher fat creams
- Increased risk of curdling
Heavier creams
-Whipped or used in sauces
-High fat content stabilizes foams & sauces
Note: different from eggs where fat limits foam
High fat prevents curdling
-Fat globule’s surface membrane latches onto proteins
Double, clotted, plastic creams
Spreads
whipping cream into foam
Whisk or whip pulls air bubbles into cream
- Protective fat membranes are broken
- Fat globules form walls around air bubbles
When whipping cream into foam how cold should the bowl be
40-50°F
What should you add to stabilize foam and increase whipping time
acid (lemon juice 1 tsp/cup)
What happens if cream is over beaten
the fat globules cluster together, forming butter
Steps for making butter
- concentrated cream
- pasteurize at 185 degrees F
- can add lactic acid to butter
- cool and age for 8 hours
- churn, forces fat globules together
- drain water
- add salt
*concentrated cream = 36-44% fat or heavy cream
What temperature should you cool butter to after you make it?
40 degrees F
fat will then form solid crystals
Types of butter
- sweet cream butter
- raw cream butter
- salted cream butter
- cultured cream butter
- european style butter
- whipped butter
- specialty butter
sweet cream butter
pasteurized fresh cream
raw cream butter
unpasteurized cream, is fragile & turns rancid easily
salted cream butter
1-2% added salt
cultured cream butter
European product, raw cream has been soured by lactic acid
european style butter
US made, soured with lactic acid bacteria, high fat content
whipped butter
injected w/ nitrogen gas
specialty butter
French, pastry butter, more water and milk solids removed, pure butter
what is butter consistency affected by
- diet of cow
- technique of butter maker
what makes softer butter
High polyunsaturated fat (fresh pasturage) make softer butters
what makes firmer butter
Hay/hard grains make firmer butters
Exposing fat to air and light can…
destroy fat molecules which changes flavor and increases rancidity
recommendation for storing butter
- Freezer for long term
- Dark, cold place for short term
- Wrap tightly in original wrapping
- Do not wrap in foil (metals ↑ fat oxidation)
melted butter
Heat to 250°F, H₂O boils off, sugar & proteins brown
Beurre noisette
“hazel butter,”melted & browned
Beurre noir
“black butter,” melted & cooked until very dark, acrid
Clarified butter
water & milk solids removed
- 100% milk fat, clear
- Can now use for frying without burning (can heat up to 400F°)
Ghee
Indian clarified butter
-traditionally from soured milk (lactic acid
Beurre blanc
(white butter): wine, vinegar, shallots
Hollandaise
sauce from butter, egg yolks, lemon juice)
Margarines
from liquid vegetable oils
-Soybean, cottonseed canola, sunflower, corn oils
percent fat to percent water in margarine and butter
80% fat 16% water
What is added as an emulsifier in margarine
lecithin
Hydrogenation
hardens oils, alters fatty acid structure (Trans fats)
Softer tub margarines
ess saturated
Reduced fat margarines
more water/less fat
Baking with margarine
poor quality
Yogurt
Milk fermented by lactic acid bacteria to produce curdling
bacteria in yogurt
- Lactobacillus bulgaricus & Streptococcus thermophilus
- L. acidophilus, L. casei, B. longum, B. bifidum
Frozen Yogurt
fermented milk using cultures, then mixed with milk, cream, sugar, & stabilizers
Reasons eggs are used so widely in food preparation is because they assist in _____
fomaing
binding
emulsifying
as an egg ages, what happens to the contents of the egg
1 albumin (whites) get thinner
2 the air cell sack gets larger as
the shell loses carbon dioxide through the porous shell
3the pH of the egg albumin becomes more alkaline
eggs are inspected and determined to be wholesome, unadulterated and truthfully labeled under which legislation?
The egg products inspection act of 1970
egg beaters are used for ____
lowering cholesterol in the diet
do Aracuna chicken eggs have superior nutritional content?
no - all eggs of any shell color are reasonably close in nutritional content
shell eggs that have lower cholesterol content than standard eggs are produced by
altering the feed given to the chicken
low cholesterol egg substitutes are produced how
replacing egg yolk with vegetable oil and removal of the egg yolk are both methods that can be used to produce low cholesterol eggs
The best eggs for use in making egg white foams are the ____ because _____.
fresh eggs; the whites are thicker
Lactic acid bacteria can also lower milk pH, producing curdling. Milk casein can also be coagulated through the use of a third substance, _______.
acidic substances such as citric acid, lemon juice, or vinegar.
Ultra high temp processing does what?
allows milk to be stored in aseptically sterile containers without refrigeration
regular batch pasteurization of milk occurs when milk is heated to _____ for _____.
145F for 30 or > minutes
milk based products which have bacterial cultures added for fermentation of lactose and lactic acid include
buttermilk
yogurt
acidophilus milk
kefir
What is the homogenization of milk designed to do?
disperse the fat into smaller particle size so that the fat remains distributed throughout the milk in a smooth consistent manner
The milk product sold as “acidophilus milk” has had what substance(s) added?
lactobacillus acidophilus cultures
T/F Yogurt is marketed to consumers as a good source of probiotics? This is a valid claim
True
What creates the veins found in blue cheeses such as gorgonzola, roquefort and stilton
mold ripening that occurs internally
T/F Cheeses made in europe are made from raw milk as these cheese makers value the use of the various things found in raw milk, including some bacteria, to gain the unique flavors and textures of their cheeses
True
The two main proteins in milk are curd and whey. Which one represents the largest amount?
Curds
The various flavors and aromas in the milk and cheese of cows, sheep and goats come from…
the feed given the animals, particularly hay vs fresh pasture grass
several fatty acids inherent in the animals milk
What determines whether or not cheese can be frozen?
water content
which of the following statements is true about rennet?
- it is an enzyme that traditionally was made from the stomach of a goat, calf, or lamb
- today is made from vegetable sources
- it produces a firm elastic curd
T/F high fat milk products produce better foams, such as for a latte, but the low fat milk products produce better stability in cooking, such as with cream sauces
False - opposite way around
leftover whey from cheese making is primarily used for what?
to produce nutritional supplements
main reason that clarified butter or indian ghee is used as a popular cooking medium
because the solids are removed, it can take high temperatures without burning
which butters have had lactic acid bacteria added on purpose, giving it a tangy, slightly sour taste
cultured european butter
