Food Industry of Biotechnology involves preparation of different food items that are used as common part of diet throughout the world.The presentation describes the Industrial preparation of Yogurt.

1. BY
Taimoor Shah
Syed Salman Hashmi

2. INTRODUCTION
 A dairy product produced
by Bacterial fermentation
of milk.
 Common microbes used
for fermentation are,
1. Lactobacillus
bulgaricus.
2. Streptococcus
thermophilus.

3. INTRODUCTION
CONTINUED
 Lactose fermenting yeast can also be
used.
 Fermentation of lactose in milk produces
lactic acid.
 Lactic acid acts on milk proteins giving
yogurt its texture and characteristics.

4. INGREDIENTS OF
YOGURT
 Main ingredient in yogurt is milk.
 Type of milk used depends on type of yogurt.
1. Whole milk for full fat yogurt.
2. Low fat milk for low fat yogurt.
3. Skimmed milk for non fat yogurt.
 Sweeteners, flavors and fruit preparations are
used in yogurt to provide variety to the consumer.

5. STEPS IN YOGURT
PREPARATION
Adjust Milk
Composition
Pasteurize
Milk
Homogenize
Cool Milk
Inoculate
with Starter
Culture
Hold
Cool Add Flavor
or Fruits
Packaging

6. Adjust Milk Composition
 To achieve desired fats and solid
content.
 Ingredients such as stabilizers are
added at this time.
 Stabilizers include gums, starch, pectins
and gelatins etc.

7. Pasteurize Milk
 At 85°C for 30 minutes or 95°C for 10
minutes.
 A high heat treatment is used to
denature the whey (serum) proteins.
 The high heat treatment reduces the
number of spoilage organisms in the
milk and provide a better environment
for the starter cultures to grow.

8. Homogenize
 The blend is
homogenized (2000
to 2500 psi) to mix
all ingredients and
improve yogurt
consistency.

9. Cool Milk
 Homogenization is followed by cooling
milk.
 Milk is cooled to 42°C.
 Cooling is required in order to provide
ideal growth temperature for starter
culture.

10. Inoculate With Starter
Culture
 Starter culture is important for initiation
fermentation process.
 Starter culture is added into the cooled
milk.
 Microbes in the culture converts Lactose
into Lactic acid.

11. Hold
 The milk is held at 42°C until its pH
reaches 4.5.
 This temperature is suitable for starter
culture.
 This process can take several hours.

12. Cool
 The yogurt is cooled to 7°C.
 Cooling is necessary to stop
fermentation process.

13. Add Fruits and Flavors
 Fruits and flavors can
be added depending
on the type of yogurt.
 Fruits can be added in
the bottom of the cup
and inoculated yogurt
is poured on the top
and fermented.
 Fruit may also be
blended and
fermented along with
yogurt before packing.

14. Packaging
 Final step in
industrial
preparation of
yogurt.
 Yogurt is pumped
into the desired
packaging material
from the
fermentation vat.
 The packaging
material is sealed.