By – Prof.

Nirali Ambarambhai Jethaloja

Fermented milk Beverages & Manufactured Dairy

Products: Cheese,
Yogurt, Buttermilk, Acidophilus milk, Kefir

 ‘’Cheese is a type of dairy product produced in a range of

flavors, textures, and forms by coagulation of the milk protein casein.’’

 It consist proteins and fat from milk (usually the milk of cows, buffalo,
sheep).

Steps in cheesemaking

1) Prepare milk: Standardize, pasteurize, and cool milk

2) Ferment milk: Add bacteria to ferment milk and make it more acidic
3) Curdle milk: Add a coagulant to curdle milk into curds
4) Cut curd: Separate curds and whey with knives
5) Shrink curd: Cook and wash curd to dry it
6) Drain whey: Separate curds from whey
7) Salt: Add salt directly to curd, brine cheese, or rub cheese with salt
granules
8) Press: Press curds into molds to remove moisture and shape cheese
9) Age: Store cheese for days or years to develop flavor and texture
 Processing
1 ) CURDLING
 A required step in cheesemaking is to separate the milk into
solid curds and liquid whey.
 Usually this is done by acidifying (souring) the milk and adding rennet.
 The acidification can be accomplished directly by the addition of an
acid, such as vinegar.
 More commonly starter bacteria are employed instead which
convert milk sugars into lactic acid.
 Most cheeses are made with starter bacteria from
the Lactococcus, Lactobacillus, or Streptococcus genera.
 Rennet sets the cheese into a strong and rubbery gel .

2 ) CURD PROCESSING
 At this point, the cheese has set into a very moist gel.
 Some soft cheeses are now essentially complete: they are drained,
salted, and packaged.
 For most of the rest, the curd is cut into small cubes.
 This allows water to drain from the individual pieces of curd.
 Some hard cheeses are then heated to temperatures in the range of
35–55 °C (95–131 °F).
 It changes the taste of the cheese.

 Salt has roles in cheese to adding a salty flavor.

  It preserves cheese from spoiling, draws moisture from the curd.
 Some cheeses are salted from the outside with dry salt.
 Most cheeses have the salt mixed directly into the curds.

3 ) RIPENING
 Cheese ripening is the process of changing the flavor, texture, and
aroma of cheese over time.
 It can take anywhere from four weeks to 28 months, depending on the
type of cheese.

Factors that affect ripening

 Temperature: The ideal temperature for ripening is between 10–15°C.

 Humidity: The ideal humidity for ripening is between 80–90%.
 Mold: The cheese should be checked for mold growth.

Examples of ripened cheeses

 Cheddar, Swiss, Colby, brick, and Parmesan are bacteria-ripened

cheeses.
 Blue, Roquefort, Camembert, and Brie are mold-ripened cheeses.

How it happens

 Starter culture: Lactic acid bacteria in the starter culture convert

lactose into lactic acid, which lowers the pH.
 Enzymes: Enzymes released by the bacteria break down proteins into
peptides and amino acids.
 Microbes: Bacteria and mold help develop the flavor, aroma, and
texture of cheese.
 Moisture: Cheese loses moisture as it ages.

Types of chees
 ‘’Yogurt is a food produced by bacterial fermentation of milk.’’
 Fermentation of sugars in the milk by bacteria produces lactic acid,
which acts on milk protein to give yogurt.
 Cow's milk is most commonly used to make yogurt.
 Milk from buffalo, goats, mares, camels, is also used to produce yogurt.
 The milk used may be homogenized or not.
 It may be pasteurized or raw.
 Each type of milk produces substantially different results.

 Yogurt is produced using a culture of Lactobacillus

delbrueckii subsp. bulgaricus and Streptococcus thermophilus bacteria.
 Other lactobacilli and bifidobacteria are sometimes added during or
after culturing yogurt.
 Some countries require yogurt to contain a specific amount of colony-
forming units (CFU) of bacteria; for example, in China the requirement
for the number of lactobacillus bacteria is at least 1 million CFU per
milliliter.
 The bacterial culture is mixed in, and a warm temperature of 30–45 °C
(86–113 °F) is maintained for 4 to 12 hours to allow fermentation to
occur, with the higher temperatures working faster but risking a lumpy
texture or whey separation

Nutrition
 Yogurt (plain yogurt from whole milk) is 81% water, 9% protein, 5% fat,
and 4% carbohydrates, including 4% sugars .
 A 100-gram amount provides 406 kilojoules (97 kcal) of dietary energy.

Production
Flow Diagram for Yogurt Processing

Types of Yogurt
 Buttermilk is a fermented dairy drink.
 Traditionally, it was the liquid left behind after churning butter out
of cultured cream.
 made up of water, milk proteins, milk sugars (lactose) and a small
amount of fat .
 Also known as chaach, moru, majjige, majiga and mattha

Types of Butter milk

 Traditional/Churn Butter milk:
 The liquid left over from making butter is known as traditional
buttermilk.
 Traditional buttermilk is very low in fat .

Cultured buttermilk:
 Most modern buttermilk is cultured buttermilk.
 made from low-fat or skim milk and has less than 2 percent fat and
sometimes none.
 It is prepared from skim or lowfat milk by fermentation with bacteria
that produces lactic acid.
 The resulting product is thicker than traditional butter milk.
 Cultured buttermilk can be consumed as a thick and creamy beverage
or used in cooking.

Acidified Buttermilk:
 Acidified buttermilk is a related product made by adding a food-grade
acid (such as lemon juice) to milk.
 It can be produced by mixing 1 tablespoon of vinegar or lemon juice
with 1 cup of milk and letting it sit until it curdles, about 10 minutes.
 In the process which is used to produce paneer such acidification is
done in the presence of heat.
  Acidophilus milk is a probiotic drink, which is a product of milk
fermentation by the bacteria Lactobacillus acidophilus.
 Lactobacillus acidophilus produce lactic acid from lactose.
 Lb. acidophilus is considered to be a probiotic bacterium

Production
1. Heat milk to 95.8°C or higher to eliminate competing bacteria and
enhance the growth of L. acidophilus

2. Homogenize the milk

3. Cool the milk to 37.8°C

4. Inoculate the milk with 2–5% of a commercial L. acidophilus culture

5. Incubate the milk for 12–24 hours

6. Cool the milk to 58°C

7. Store the milk under refrigeration

Benefites
1) preventing or controlling intestinal infections,

2) improving lactose digestion in persons classified as lactose maldigestors,

3) helping control serum cholesterol levels

 Kefir grains are small white balls containing billions of microorganisms
that transform milk into kefir.

 Kefir is a fermented milk drink similar to a thin yogurt that is made

from kefir grains, a specific type of mesophilic symbiotic culture.

 It is prepared by inoculating the milk of cows, sheep with kefir grains.

Composition
 include dietary minerals, vitamins, essential amino acids,
and conjugated linoleic acid,
 Several dietary minerals are found in kefir, such as calcium,
iron, phosphorus, magnesium, potassium, sodium,
copper, molybdenum, manganese, and zinc.
 Kefir contains vitamins in variable amounts, including vitamin A, vitamin
B1 (thiamine), vitamin B2 (riboflavin), vitamin B3 (niacin), vitamin
B6 (pyridoxine), vitamin B9 (folic acid), vitamin
B12 (cyanocobalamin), vitamin C, vitamin D, and vitamin E.
 Essential amino acids found in kefir
include methionine, cysteine, tryptophan, phenylalanine, tyrosine, leuci
ne, isoleucine, threonine, lysine, and valine.
 Probiotic bacteria found in kefir products include: Lactobacillus
acidophilus, Bifidobacterium bifidum, Streptococcus
thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus
helveticus, Lactobacillus kefiranofaciens, Lactococcus lactis,
and Leuconostoc species.

Production
1. Pasteurize: Heat milk to 90°C for 15 minutes, then cool to 25°C.

2. Add kefir grains: Mix 5% kefir grains into the milk.

3. Incubate: Keep the milk at 18–24°C for 18 hours.

4. Separate: Strain the kefir grains out using a sieve.

5. Store: Refrigerate the kefir at 4°C.