Introduction
Yogurt is a fermented milk product. It is made by mixing specific bacteria cultures in warm pasteurized milk. The culture-mixed milk is incubated at that temperature for a few hours. Yogurt is normally made from cow or buffalo milk.
Depending on the type of milk used for making the Yogurt, the Yogurt can be:
- Full-fat Yogurt (made from full-fat milk)
- Low fat Yogurt (made from toned milk)
- Or no fat Yogurt (made from no-fat milk).
When you visit the supermarket, you may be surprised to see multiple types of packed yogurt. By making small changes in the production of Yogurt, many types of Yogurt can be created by adding fruits, flavors, syrups, etc.
This article briefly discusses the following major types of Yogurts.
- Plain Yogurt
- Greek Yogurt
- Set Yogurt
- Stirred Yogurts
- Drinking Yogurt
- Flavored Yogurt
- Aseptic Yogurt
- Plant-based Yogurt
Plain Yogurt
Follow the standard step-by-step process of fermenting milk into Yogurt using the recommended starter bacteria culture and temperature program. Do not add any fruits or flavor, the resulting product will be plain Yogurt.
Qutab is a (pronounced gu’tab in Azerbaijani) stuffed dish made from dough. The stuffing can be vegetarian or non-vegetarian. The construction of Qutab is not exactly the same as Indian Paratha, but they look similar. Qutab is served with plain Yogurt. Please visit https://en.wikipedia.org/wiki/Qutab to learn more about this.
Greek Yogurt
Greek Yogurt has other names, strained Yogurt and Yogurt cheese. Greek Yogurt is obtained by straining out the whey from it. It is thicker than the normal Yogurt. It has the typical sour taste of Yogurt. It contains more protein than normal Yogurt but may lose some calcium in the drained whey.
Greek Yogurt, despite its Greek tag, did not originate in Greece! The name Greek Yogurt was popularized by a Greek company that manufactured and commercialized Yogurt.
Set Yogurt
The milk added with Yogurt culture is filled into cups and bottles. Pieces of fruit or fruit juices can be added to the cup. The cups filled with Yogurt milk are placed in a crate and moved to the incubation room maintained at 38-42 ⁰C (100-108 ⁰F). The period of incubation is 6 to 8 hours till the pH value reaches 4.5. By this time, the Yogurt will have a gel-like structure.
After incubation, the crates with set Yogurt cups are moved to the cold room. And the Yogurt cups are continuously cooled to under 10 ⁰C (50 ⁰F) by blowing cold air. The cooling should be gradual. Rapid cooling may result in a fast concentration of gel and a layer of whey may appear on the surface.
The set Yogurt packed in cups and crates are stored in cold storage at 5 ⁰C (41 ⁰F) or less till the time of dispatch.
Stirred Yogurts
The milk mixed with Yogurt culture is held at 38-42 ⁰C (100-108 ⁰F) for 6 to 8 hours in a Yogurt vat (by passing hot water in the jackets of Yogurt vat) till the pH value reaches 4.5. Now, the Yogurt is cooled to 25 ⁰C (77 ⁰F) by passing chilled water in the jackets. Allowable fruits or fruit juices are added and gently stirred.
The Yogurt is cooled to 7 ⁰C (44 ⁰F) to stop further fermentation. It is pumped into the packing machine for final packing of Stirred Yogurt in cups, bottles, etc. The structure of the stirred Yogurt is less solid compared to a set Yogurt.
Drinking Yogurt
You can say drinking yogurt is the same as stirred Yogurt but with a higher amount of stirring. The stirred Yogurt is packed after stirring. However, slight coagulation may reoccur after packing. Drinking Yogurt is served chilled.
Flavored Yogurt
Flavored Yogurt is plain Yogurt added with fruits or berries or fruit syrups. The additions are done just before packing the plain Yogurt into cups.
Aseptic Yogurt
Aseptic Yogurt is Yogurt packed in aseptic packages. Aseptic Yogurt will have a higher shelf life and refrigeration is not needed until the pack is opened. The processing of milk may be different for Aseptic Yogurt like the pasteurization process (for Yogurt milk) may follow a higher temperature cycle.
Plant-based Yogurt
Plant-based Yogurt is normally prepared using milk developed from Soy, coconut, almonds, etc. Plant-based milk does not have Lactose. Hence bacterial culture used for fermenting milk-based Yogurt cannot be used for plant-based yogurt.
Plant-based Yogurts contain different culture bacteria viz. Lactobacillus casei, Lactobacillus rhamnosus, and Bifidobacterium bifidum.
The advantage of plant-based Yogurt is it can be consumed by people allergic to lactose and vegans. However, the components and structure of plant-based milk are quite different from dairy milk. Also, the Yogurt made from plant-based milk will never have the taste of dairy milk Yogurt.
Conclusion
Dahi (curd) is the most preferred fermented milk product for Indians. However, Yogurt is slowly gaining popularity as a beverage drink, health food, and microbial characteristics. However, its popularity may be limited to the upper middle class and affluence since the cost of Yogurt is appreciably higher than Dahi.
You may read the following articles.
Difference between Dahi (curd) and Yogurt
What is Yogurt and how is it made
What is Dahi/Curd and how it is made in Dairy
Popular Fermented Milk Products in India
Caution
Yogurt is made from milk. If you have issues like allergies to milk, or lactose intolerance, you must not eat or drink any form of Yogurt without consulting your doctor.
References
https://en.wikipedia.org/wiki/Yogurt
https://www.teagasc.ie/rural-economy/rural-development/diversification/production-of-yoghurt