All you need to know about Yoghurt!!

 YOGHURT

It is a dairy-based fermented product produced by probiotic microbial strains such as Lactobacillus Bulgaricus, and Streptococcus Thermophilus. Probiotic bacterial strains are known for providing good gut health.

What is the difference between curd (known as dahi in India) and Yoghurt??

Both are fermented products. However, the strains used in the dahi and yoghurt are completely different. In addition to that, the total solids in the yoghurt is higher than the dahi. Other similarities between the two products include that during pre-treatment in pasteurization both curd milk and yoghurt milk are held for a long time in a holding cell. This long holding time is helpful for protein denaturation. Hence, results in good texture and mouthfeel of the end products. 

Process Flow:

Milk is initially standardised for the fat content and dry matter content. Ingredients like sugar, thickeners and stabiliser are added. Then Yoghurt milk is deaerated, homogenized and pasteurized at (90-98 deg C) for 5 minutes. After pasteurisation, at cold conditions, the inoculum is added to the yoghurt milk for fermentation. Based on the fermentation and further processing yoghurt has been classified as follows. After fermentation, inclusion is added (optional) before packaging and distributed at cold (less than 8 deg C) or ambient conditions depending on the type of yoghurt.

Types of yoghurt depending on the processing method:

1. Set yoghurt (usually fermented in the package during storage) similar to curd
2. Stirred Yoghurt (fermented in the tanks)
3. Drinking Yoghurt (fermented in tanks then viscosity is reduced by homogenizer during cooling)
4. Concentrated Yoghurt (fermented in tanks and then concentrated by means of centrifugation or filtration)- Ex. Greek yoghurt
5. Ambient Yoghurt based products (stirred yoghurt and drinking yoghurt are subjected to further heat treatment (sterlisation) for ambient distribution)

Shear sensitive:

Yoghurt is a Non-Newtonian fluid with shear thinning characteristics. This means the apparent viscosity of the yoghurt will be decreased during the increased shear rate. Shear rate during pumping and agitation disrupt the structure of yoghurt. It will reduce the viscosity of prepared yoghurt. Stirred yoghurt is the shear sensitive yoghurt.