Standardisation of fat content in milk
The fat content (g100g-1) of yoghurt manufactured in different parts of the world can vary from as low as 0.1 to as high as 10 and in order to meet existing or proposed compositional standards for yoghurt, it is necessary to standardise the milk. For example, a typical average butterfat content in milk ranges from 3.7 to 4.2g 100g-1 (Fig. 2.3), but the fat content of commercial yoghurt averages around 1.5 g 100 g-1 (medium fat yoghurt) or 0.5 g100g-1 (low fat yoghurt).
The methods employed for standardisation are as follows:
• removal of part of the fat content from milk
• mixing full cream milk with skimmed milk
• addition of cream to full fat milk or skimmed milk
• a process which may combine some of the methods mentioned above, that is,
the use of standardising centrifuges.
The components required to achieve a standard milk, using one of the abovemethods, can be easily calculated using the Pearsons Square method.