Industrial Preparation of Yogurt

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. INDUSTRIAL Preparation OF YOGURT BY Taimoor Shah Syed Salman Hashmi

2. INTRODUCTION A dairy product produced by Bacterial fermentation of milk. Common microbes used for fermentation are, Lactobacillus bulgaricus . 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. Whole milk for full fat yogurt. Low fat milk for low fat yogurt. 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

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.

15. QUESTIONS?