Yoghurt is firm, creamy or liquid acidified milk products manufactured from pasteurized milk by use of thermophilic lactic acid bacteria.
In order to increase the dry matter content of the yoghurt in line with the given local preferences (which vary around the world), the milk can be concentrated or powder can be added to obtain a fortification - or the milk can be concentrated by means of ultrafiltration (UF). Typical standard yoghurt is not heat treated subsequent to fermentation and does not contain binding agents.
The various types of yoghurt are characterized by their structural properties. In drinking yoghurt the gel has been broken in the fermentation tank, homogenised and cooled before packaging. A lower dry matter content and homogenization after fermentation result in drinkable yoghurt with low viscosity. Normally stabilizer is added to ensure stable yoghurt without sedimentation.
The below processing parameters are general guidelines and should only be considered as such.
Processing Sequence
| Sequence |
Process/Technology |
| Processed milk |
| 1. Dry matter standardization (SNF 10-12%) |
Fortification, evaporation or UF concentration |
| 2. Deaeration (0.7-0.8 barg at 70°C) |
Deaerator module |
| 3. Homogenizing (one stage, 220 barg at 70°C) |
Homogeniser module, Niro Soavi, NANOVALVE |
| 4. Heat treatment (95°C for 5 min.) |
Heat treatment, PHE Systems/VARITHERM |
| 5. Inoculation of starter culture |
Inoculation module |
| 6. Fermentation (long or short time) |
|
| 7. Possible addition of stabilizer |
|
| 8. Homogenizing |
Homogeniser module, Niro Soavi |
| 9. Cooling |
Ecoflex/VARITHERM |
| 10. Fruit/flavour dosing |
Aseptic fruit mixing module |
| 11. Filling |
GEA Procomac |