5. Fruit preparation applications

5.1 Yoghurts

The name "yoghurt" can only be used if fermentation is carried out by two lactic bacteria: Streptococcus thermophilus and Lactobacillus bulgaricus. Thanks to their action, which is optimal at a temperature of 44°C, milk lactose is transformed into lactic acid. Acidification of the medium (pH ~ 4.5) forms a gel and generates new aromas (acetaldehyde).

A distinction is made between firm yogurts and stirred or drinking yogurts:

• firm yogurts are packaged in jars immediately after inoculation with lactic ferments. They are then placed in an oven, where fermentation takes place. Once the desired degree of acidity has been reached, they are stored in a cool place (+4°C);

• stirred...