Yogurt is a basic fermented milk product that usually contains the basic bacterial starter cultures of Lactobacillus bulgaricus and Streptococcus thermophillus.
Although the composition of different types of yogurts changes but there is some fixed composition of fats present in them. It is important to note that all yogurts must contain at least 8.25% of solid which is not fat. The fat composition changes with the type of yogurt like full fat yogurt must contain not less than 3.25% of milk fat whereas low fat yogurt must not contain more than 2% milk fat. Also there is a category of non fat yogurt where the fat composition is even less than 0.5%.
The yogurt is basically a mixture of milk and cream which is then fermented by using a culture of Lactic acid producing bacteria. The types of milk which can be used are whole, reduced-fat, low-fat or non-fat depending on which the type of yogurt is decided. The lactic acid produced by the starter culture bacteria is basically responsible for lowering the pH of the yogurt making it acidic and tart. This finally causes the milk protein to thicken. These bacteria ferment the milk which results in the production of yogurt leads to partial digestion of the milk making it more easily digestible. In addition, these bacteria also act as a beneficial microorganisms for the human body as they act as oral-antibiotic therapy and helps in eliminating the pathogenic-bacteria from the gut and replenishing the non-pathogenic bacteria.
Ingredients of yogurt –
Sweeteners (e.g. sugar, honey, aspartame, etc)
Flavorings (e.g. vanilla, coffee, etc)
Other ingredients (e.g. fruits, preserves, stabilizers such as gelatin)
Types of yogurt –
- Set yogurt – This type of yogurt has a jelly-like structure and texture and is incubated and cooled in a final package.
- Stirred yogurt – This type is less firm than set yogurt. It is incubated in a tank and final coagulum is broken by stirring before cooling.
- Drinking yogurt – It also has coagulum broken before cooling though very little reformation of coagulum will occur.
- Frozen yogurt – This type of yogurt is incubated in the same way the stirred yogurt is incubated. It has an ice-cream like texture.
- Flavored yogurt – In this type of yogurt, flavors are added just before yogurt is poured into pots and the sugar content present in this type of yogurt is about 50%.
General processing of yogurt –
- Adjusting milk composition and blending all the ingredients
- Pasteurization of milk (at 85 degrees celcius for 85 minutes)
- Homogenization of milk (2000-2500psi)
- Cooling of milk to 42 degree celcius
- Inoculation with bacterial starter cultures into the cooled milk
- pH reduction by waiting for sometime
- Again cooling to 7 degree celcius
- Addition of fruits and flavors
- Packaging of prepared yogurt.
Health benefits of yogurt:
• Yogurt is comparably easier to digest than milk.
• It is rich in variety of vitamins.
• It is a rich source of protein.
• As it is source of protein, it may help in losing weight and gain muscles.
• It acts as a booster for immune system
• It is also important and useful for digestive system. It destroys the pathogenic microorganisms from the gut.
• It is good for bones especially for kids and elderly
• It may also be useful in lowering the blood pressure.