Title: FDNS 1301 Introduction to Foods Milk and Dairy Products
1FDNS 1301Introduction to FoodsMilk and Dairy
Products
2Composition of milkProteins
- 82 casein, rest in whey (lactalbumin,
lactoglobumin) casein dispersed in milk
serum susceptible to coagulation by low pH
(4.6) whey proteins not affected by acid but
are coagulated by heat
3 Whey Protein concentrate (WPC) and Whey
Protein Isolates (WPI) produced by
ultrafiltration (gelling agent)
4Fats
- milk is an emulsion (oil in water)
mainly composed of triglycerides fats
normally form loose clusters in unhomogenized
milk clusters grow in size during
standing results in cream layer at top
5Carbohydrates
- main sugar is lactose (glucose /
galactose) Lactose Intolerance inability
to breakdown lactose in small intestine due to
low quantities of the enzyme lactase gas,
cramping and diarrhea results simple test
(mucus reaction on tongue)
6Color
- light reflection from casein and calcium
phosphate salts contains two pigments - 1. Carotene in milkfat levels depend upon
feed and metabolism (change to Vitamin A) 2.
Riboflavin water soluble suspended in whey
7Flavor
- sweet from lactose mouth feel from fat
content off-flavors from the following1.
heat processing2. feed consumed3. bacteria
action4. chemical changes5. foreign flavors6.
oxidation
8Acid levels
- pH of 6.6 lowers over time from release
of CO2 sour milk produced from lactose in
unpasteurized pasteurized milk spoiled from
putrefactive bacteria
9Milk Classifications
- 1. Fluid Milk Whole Fresh milk from the
cow with nothing removed or added (except Vitamin
D) Skim or nonfat Most of the fat removed
(less than 0.5 ) Can be fortified
10Fluid Milk cont.
- Low fat Fat content between 0.5 and 3
Can be fortified Ultrahigh-temp. processed
sterilized milk in tetra packaging
112. Concentrated Fluid Milk
- Evaporated Milk, whole or skim with 60 of
its water removed, sterilized and canned (cooked
flavor) Condensed Whole milk with 60 of
its water removed and sweetened with sugar
123. Dry Milk (moisture 3)
134. Cultured or Fermented Products
- Yogurt Milk cultured by bacteria to a
custardlike consistency Most has additional
milk solids added Some is flavored and
sweetened
144. Cultured or Fermented Products
- Cultured Buttermilk fresh milk cultured or
soured by bacteria Real Buttermilk Liquid
remaining after the whey is drained off after
butter making Acidophilus Milk cultured by
bacteria that consume lactose Used by
lactose intolerant people
15 Milk Classifications
- 5. Filled Milks (other fat with nonfat milk
solids) 6. Imitation milks (no milk products)
16Cream
- high fat liquid separated from whole milk
min. 18 milkfat
17Types of cream
- half and half (18) light (30-36)
heavy (36 minimum) sour cream
(commercially cultured light cream) creme
fraiche (sour cream, yogurt and buttermilk
fermented together) Non-dairy Products
Cool Whip
18Sanitation concerns
- Pasteurization heating of a product to
specific temperatures to destroy most bacteria,
decrease spoilage and increase storage
times. two typesA.145F for 30
minutesB.162F for 15 seconds
19Sterilization
- ultrahigh temperatures to kill all
microbes 280F - 302F for 2 to 6 seconds
20Storage Concerns
- remember that pasteurization does not kill
all microbes refrigerate at 45F or
lower prevent light exposure (oxidation of
fat, degradation of vitamin D) tight seal to
prevent odors
21Food Preparation ConcernsEffects of heat
- whey proteins precipitate due to
insolubility coagulation at 150F
collection on bottom and sides of pots when
exposed to direct heat casein does not
coagulate at normal levels and temperatures
accelerated coagulation in presence of acid
some browning due to Maillard reaction
22Acid coagulation
- very sensitive to acid lowered pH
coagulates casein (curd)
23Enzymes
- rennet at optimum temp and pH coagulates
casein
24Freezing
- ruptured emulsifying agent fat globules
coalesce setting of proteins
25Milk foams
- foaming agent (protein) thats dispersed in
a liquid (water) with a stabilizing agent (fat)
to hold gas bubbles (air) whipping cream
sometimes not homogenized most proteins
tied up around increased fat globules not
enough to cover air bubbles
26Factors affecting Milk Foams
- 1. Temperature cold temp cream whips
better want to increase clumping of fat for
stabilization agitation results in
clumping lower temp. increases viscosity
272. Viscosity
- thicker creams have more fat globules
therefore stabilize foam aging increases
viscosity
28 Factors affecting Milk Foams
- Fat Content
- 4. Amount of Cream
- 5. Other Substances sugar decreases volume
and stiffness sugar increases time of
whipping if added at beginning of process
29Cheese and Cheese Products
- draining the whey after the coagulation of
casein due to acid and/or enzymatic activity
resulting in curds curds may have further
action by heat, bacteria or pressure high
quality milk used
30Steps to form cheese
- 1) Curd formation2) Cutting curd
into small pieces to release whey3) Heat
curds to remove additional whey4)
Draining, salting and ripening5) Curing
or ripening
31Ripening
- otherwise known as aging outer rind
formed (either naturally or by spraying with a
culture) lactose converted to lactic
acid proteins broken down and curd
softens flavors developed from above process
and initial milk components
32Types of ripening
- Interior ripened occurs throughout entire
bodybacteria cheddar, Swiss, parmesanmold
blue cheeses - Surface ripening ripening from surface to
insidebacteria limburgermold brie,
camembert - Unripened (Cottage, cream)
33Classification of cheeses
- 1) Soft, unripened (cottage)2) Firm,
unripened (mozzarella)3) Soft, ripened
(brie)4) Semisoft, ripened (Monterey
Jack)5) Firm, ripened (cheddar, Colby,
gouda)6) Very hard, ripened (parmesan,
romano)7) Blue-vein mold ripened
(blue)8) Goat Cheeses
34Cheese Products
- 1. Cold-Pack Cheese- mixture of cheeses
(cheaper Parmesan imitations) 2. Process
Cheese (Kraft slices) 3. Process Cheese Food /
Spread (Velveeta, Cheez Whiz)