Cheese

Cheese production

1. SOLID CULTURED DAIRY
PRODUCTS

2. Cheese
•A food consisting of the coagulated, compressed, and
usually ripened curd of milk separated from whey
•The curd of milk separated from whey, often seasoned
and aged
•A food derived from milk curd produced in a wide range
of flavors, textures, and forms by the coagulation of the
milk protein casein

3. Etymology
The word CHEESE comes from the Latin
term caseus, from which the modern
word casein is also derived. However,
the earliest source is from the proto-
Indo-European root kwat-, which means
"to ferment, to become sour".

4. Types of Cheese

1. Fresh Requires high acidity by bacterial action
E.g., Cottage cheese, Cream cheese
2. Soft Requires slow acid development, washing
to control lactose and minimal cooking time
E.g., Brie, Camembert, Mozzarella and Gouda
3. Hard Requires high acid development and high
temperature
E.g., Cheddar, Parmesan, and EdamCheddar

5. Steps in Cheese Production

1.Curdling
•Milk Preparation
•Acidification
•Coagulation
2. Curd Processing
•Draining
•Salting
•Molding
Others: Stretching, Cheddaring, Washing
3. Ripening

6. Other Curd Processing Techniques
•Stretching (Mozzarella, Provolone) The curd is
stretched and kneaded in hot water, developing a
stringy, fibrous body.
•Cheddaring (Cheddar, other English cheeses) The
cut curd is repeatedly piled up, expelling more water.
The curd is also mixed (or milled) for a long time,
taking the sharp edges off the cut curd pieces and
influencing the final product's texture.
•Washing (Edam, Gouda, Colby) The curd is washed
in warm water, lowering its acidity and making for a
milder-tasting cheese.
11/07/14

8. CURDLING
1. Milk Preparation
•Heat treatment, filtration, and standardization
2. Acidification
•Addition of starter cultures
E.g., Streptococcus spp. for cheddar, Gouda and
cottage cheese. Lactobacillus spp. (L. bulgaricus and
L. acidophilus) for Swiss and Grana cheeses.
•These microorganisms will ferment the carbohydrates
present in milk into lactic acid
•NOTE: pH should be reduced to about 4.7, the optimum
for milk coagulation.
11/07/14

9. CURDLING
3. Coagulation
•Involves the action of rennet (rennin or chymosin) on
casein micelles in milk
•Rennet is a stomach extract of young unweaned calves
that contains chymosin
•Chymosin coagulates milk optimally at pHs 6.0-6.4 at 20-
30°C, although its optimum pH is ca. 4
•The optimum temperature for coagulation is ca. 40°C,
but milk for cheesemaking is coagulated with rennet at
31-32°C because, at this temperature, the curd is
rheologically most suitable for cheesemaking.
11/07/14

10. 11/07/14
A white, tasteless, odorless protein precipitated
from milk by rennin
•Present as macromolecular aggregates or
micelles
•Responsible for the white color of milk, which is
due to the light reflected by the micelles
•It makes milk a colloidal dispersion
CASEIN

11. •Comprises 45–50% a-casein, 25–35% b-
casein, 8–15% k-casein, and 3–7% g-casein.
•Each casein fraction differs in sensitivity to
calcium, solubility, amino acid makeup and
electrophoretic mobility.
•k-Casein Soluble in calcium solutions, which
would normally precipitate other casein
fractions. Important in stabilizing casein
micelles
11/07/14
NOTES ON CASEIN

12. CASEIN STRUCTURE
11/07/14
k-casein Other
casein

13. Milk Coagulation by Chymosin
Introducing chymosin to milk in cheesemaking,
normally at about 32°C, destabilizes the casein
micelle in a two-step reaction:
1. Primary (enzymatic) phase
2. Secondary (nonenzymatic) phase
11/07/14

14. 11/07/14
Chymosin cleaves the phenylalanine-methionine
bond (105-106) of k-casein, thus eliminating its
stabilizing action on calcium-sensitive a- and b-
caseins.
PRIMARY PHASE

15. 11/07/14
The micelles without intact k-casein aggregate in
the presence of ionic calcium in milk and form a gel
(curd).
SECONDARY PHASE
Ca
2+
Ca
2+ Ca
2+
Ca
2+
Ca
2+ Ca
2+
Ca
2+
Ca
2+
Ca
2+
Ca
2+

16. CURD PROCESSING
1. Draining
•Cutting of curd into small cubes to allow water to drain
from individual pieces of curd.
•Expulsion of whey results in shrinkage accompanied by
further degradation of κ-casein, which may lead to the
formation of new crosslinks in the rennet gel or curd and
the development of a firmer or more rubbery curd.
2. Salting
•Influences flavor, moisture and texture
•Salting also causes the removal of whey and slows down
the rate of acid development as well as inhibits growth of
undesirable bacteria
11/07/14

17. CURD PROCESSING
3. Molding or Shaping
•Most cheeses achieve their final shape when the curds
are pressed into a mold.
•During molding, the curd is comminuted and shaped in a
mold using a hydraulic press.
•The harder the cheese, the more pressure is applied.
•The pressure drives out moisture --- the molds are
designed to allow water to escape --- and unifies the curds
into a single solid body.
11/07/14

18. RIPENING
•A newborn cheese is usually salty yet bland in flavor
and, for harder varieties, rubbery in texture. Therefore,
most cheeses are ripened under controlled conditions
to develop the required texture and flavor.
•Ripening (affinage) is the ageing and maturing of
cheese.
•Lasts from a few days to several years
•As a cheese ages, microbes and enzymes transform
texture and intensify flavor. This transformation is
largely a result of the breakdown of casein proteins
and milk fat into a complex mix of amino acids, amines,
and fatty acids.
11/07/14

19. CHEDDAR CHEESE
A relatively hard, pale yellow-to-off white (unless
artificially colored) sometimes “sharp”tasting
natural cheese
•Close and firm in texture, yet mellow in character
or quality; it is rich with a tendency to melt in the
mouth, the flavor full and fine, approaching that of
hazelnut” --- Joseph Harding
•Originated from the English village of Cheddar in
Sommerset
•Most popular cheese in the UK, second in the US

20. CHEDDAR PRODUCTION PROCESS
1.Curd and whey separation using rennet.
2.Cheddaring. The curd, after heating, is
kneaded with salt, cut into cubes to drain the
whey and then stacked and turned.
3.Ripening for up to 15 months. The cheese is
kept at a constant temperature often
requiring special facilities.
NOTE: Caves provide an ideal environment
for maturing cheese.
11/07/14

21. CHEDDAR PACKAGING
Cheddar cheese used to be packaged in black
wax, which then changed to larded cloth, which
is impermeable to contaminants, but still allows
the cheese to breath. However, this practice is
now limited to artisan cheese makers.
11/07/14

22. …
(Unopened) Fridge Freezer
Past Printed DatePast Printed Date
Hard Cheese
(Parmesan, Asiago,
Romano) lasts for
2-4 Months 6-8 Months
Shredded Hard
Cheese lasts for
1-2 Month 6-8 Months
Semi-Hard Cheese
Chunk (Cheddar,
Swiss) lasts for
1-2 Months 6-8 Months
Sliced Semi-Hard
Cheese lasts for
1 Month 6-8 Months
(Opened) Refrigerator Freezer
Hard Cheese Chunk
(Parmesan, Asiago,
Romano) lasts for
3-6 Weeks 6-8 Months
Shredded Hard
Cheese lasts for
3-4 Weeks 6-8 Months
Semi-Hard Cheese
Chunk lasts for
3-6 Weeks 6-8 Months
Sliced Semi-Hard
Cheese lasts for
2 Weeks 6-8 Months
11/07/14
The shelf life of hard
cheese is influenced by a
variety of factors, such as
the type of cheese, the
processing method and
packaging date, its
exposure to heat, how the
cheese is stored and
the best by date or sell by
date. So how long does
cheese last?  When
properly stored at or
below 40° F, the shelf life
of cheese is as follows:
Shelf Life of Cheese

23. Which types of cheese can
be frozen?
Does Cheese FreezeThawed Result
Does Cream Cheese
Freeze
Not well Chunky and Watery
Does Ricotta Cheese
Freeze
Not Well
Runny – Separated
and Watery
Does Brie Cheese
Freeze
Yes Grainer texture
Does Cheddar Cheese
Freeze
Yes Crumblier
Does Mozzarella
Cheese Freeze
Yes Rubbery & Yellow
11/07/14

24. Facts about cheese freezing
•The firmer the cheese, the longer its shelf life. It’s the same
with cheese quality after freezing.
The best cheese to freeze is shredded firm cheese. Firmer
cheeses freeze better, especially if they are shredded. Blocks
of cheese also freeze well, but they tend to crumble instead
of slicing nicely after thawing.
•Softer cheeses do not freeze well because the moisture
within the cheese forms ice crystals. When defrosted, these
crystals destroy the texture of the cheese. So softer cheeses
are grainy after freezing, the texture is more noticeably
altered.
•*Note: Any cheese, once defrosted, is better if used for
cooking than just eating plain.
11/07/14