This document provides information about the manufacturing processes of yogurt and dahi. Yogurt is made by fermenting milk with Lactobacillus bulgaricus and Streptococcus thermophilus cultures, giving it a tart flavor. Dahi is similarly made by fermenting milk or cream but uses different starter cultures. Both products are high in protein and beneficial bacteria. The processing involves steps like standardizing, pasteurizing, homogenizing, cooling, inoculating with cultures, incubating, and packaging the fermented milk.

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2. Manufacturing Process of Yogurt
and Dahi
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3. Yogurt
 Fermented milk product
 Have tart and acidic flavor
 Contains characteristic bacterial cultures lactobacillus
bulgaricus and streptococcus thermophilus
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4. Dahi
 Fermented dairy product
 Pleasant acid taste with sweetish aroma and three
distinct phases:
1. Creamery layer on top
2. Homogenous body of curd and sift and glossy
surface
3. Watery portion at bottom
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5. Difference Between Yogurt and
Dahi
Yogurt Dahi
 More acidity
 Starter include
Lactobacillus
bulgaricus and Strept
ococcus thermophilus
 Addition of artifitial
sweetners and flavors
 Relatively less acidity
 Starter includes
Lactococcus lactis,
Streptococcus
thermophilus,
Lactobacillus
bulgaricus and
lactose fermenting
yeasts
 Natural flavors 6/7/20155

6. Health Benefits of Dahi and
Yogurt
Cure of
gastrointesti
nal
diseases
• Chronic
constipation,
• Diarrhea,
• Dysentery,
• Chronic
appendicitis
• Gastric ulcer
Highly
beneficial
in
treatment
of
diabetes
More
digestibilit
y than
that of
milk and a
good
source of
probiotics
Prevent
skin
disorders
and pre-
mature
aging
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7. Cont…
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8. Nutritional Facts of Yogurt
Nutrients Amount/100g
Total fat 0.4 g
cholesterol 5 mg
sodium 36 mg
potassium 141 mg
carbohydrates 3.6 g
sugar 3.2 g
protein 10g
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9. Nutritional Facts Of Dahi
Calories 179/100g
Total fat 6g
Cholesterol 0g
Total carbohydrates 27g
Sugars 23g
Proteins 4g
Dietary fiber 5g
Calcium 19%
Vitamin A&C 0%
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10. Types of Yogurt
 Natural yogurt
 Clean, slightly acidic, tart flavor
 Flavored yogurt
 Added sugar or artificial sweeteners
 Greek and Greek-style yogurt
 Deliciously thick and creamy texture
 Set yogurts
 Fairly thick, flat surface with fruit or
flavorings at base
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11. Cont…
 Made with active cultures
 Not heat-treated
 Retain live and active cultures
 Sundae or fruit-on-the-bottom
 Fruit on the bottom, so that
turned upside down
 Stirred yogurt
 Fermented in bulk with the fruit
or flavoring stirred in
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12. Cont…
12
 Drinking yogurt
 Stirred, diluted and mixed with flavors,
fruit juices
 Frozen yogurt
 Blend of sugars, stabilizers, emulsifiers
and flavors in natural stirred yogurt
 Labna
 Drained of whey to form a fresh yogurt
‘cheese’
 Flavored and rolled into balls
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13. Types of Dahi
 Plain Dahi
 Probiotic Dahi
 Have additional friendly bacteria
 Give added advantage to
consumers
 Sweet dahi
 With 0.7% acidity
 Sour dahi
 With 1% acidity
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14. Yogurt and Dahi Chemistry
 Starter cultures in yogurt
 Lactobacillus bulgaricus and streptococcus
thermophilus
 Ferment lactose to produce lactic acid
 Lactic acid
 Provides the tart flavor of yogurt
 Cause formation of a gel structure
 Decreases ph
 Causes the milk to clot
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15. Cont…
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 Milk gel
 Solid structure consisting of a protein matrix and other
components
 Has ability to immobilize the liquid phase of milk
 Curdling is induced by proteolytic enzymes, lactic
acid, heat, and other means

16. Yogurt Processing Line
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17. Cont…
17
Receiving
of milk
Initial
treatment
of milk
Standardization
of milk
components
Homogenization
Pasteurizatio
n
Inoculation/
fermentation
Incubation
Cooling
Mixing with
fruit
preparation
Packaging
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18. General Yogurt Processing
Steps
 Initial Treatment of Milk
 Centrifugal clarification to remove somatic cells and
solid impurities
 Thermalization at 60–69 °C for 20–30 s
 For killing vegetative microbs
 Partial inactivation of some enzymes
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19. Cont…
 Standardization
 Milk composition adjusted for desired fat and solids
content
 Fat content ranges from 0.1%–10%
 Addition of skim milk or milk fat
 The separation of fat from milk via centrifuge
 Evaporation,
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20. Cont…
 SNF of yogurt ranges from 9% to 16% adjusted by
addition of
 Skimmed milk powder,
 Milk concentrate,
 Whey powder,
 Sodium caseinate powder
 Sugars, sweeteners and common stabilisers gelatin,
pectin, agar, starch also added
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21. Cont…
 Pasteurization
 Pasteurized at 185°F (85°C) for 30 minutes or at
203°F (95°C) for 10 minutes.
 Denature the whey proteins, form more stable gel
 Reduces the number of spoilage organisms in the
milk
 Homogenization
 Homogenized at 2000 to 2500 psi
 Thorough mixing and improve yogurt consistency
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22. Cont…
 Cooling
 Cooled to 108°F (42°C) for the starter culture growth
 Inoculation with Starter Cultures
 Fermentation culture added in a conc. of about 2%
 Incubation
 Incubation at 108°F (42°C) until a pH 4.5 reached
 Fermentation form a soft gel and characteristic flavor
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23. Cont…
 Cooling
 At ph 4.5 yogurt cooled to 15-22°c to stop the
fermentation
 Add Fruit & Flavors
 Fruit and flavors added at different steps
 Depending on the type of yogurt
 Packaging
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24. Processing line for Dahi
Raw milk
Standardizatio
n/Evaporation
Pasteurization
and
Homogenization
Cooling
Inoculation and
Incubation
Packaging and
Storage
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25. General Yogurt Processing
Steps
 Standardization/Evaporation
 Enrichment of total solids by 2.5 to 3.0%
 Firmer and more viscous end product
 Homogenization and heat treatment
 Homogenization improves the stability and constancy
of products
 Imparts full bodied taste by preventing cream
separation
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26. Cont…
 Heat treatment of milk to 90-95˚C with holding time of
5-10 minutes
 Inoculation of starter culture and Incubation
 Optimum amount of inoculum to use (2%)
 Normally between 3 and 20 hrs
 Storage at low temperature;
 After incubation, finished product cooled to about 3-
5˚C
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28. Thank you
Any Question???
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