Thiamine - This nutrient is also dependent on the amount present in the feed but it is also synthetized by the lumen of the gut of the cow and is therefore present in fair amounts in cow's milk. Riboflavin - The colour of the whey is due to the presence of this nutrient. Niacin - Milk is a good source of tryptophane which is a precursor of niacin. This vitamin is easily destroyed by application of heat and exposure to air. The small amount present in the milk is destroyed during pasteurisation.
Milk is a food that is highly perishable.
Thus processing it will help to store it. Spray drying of the milk to powder or condensing it are some examples. Processing, in most cases, involves high temperatures and this destroys some of the nutritive value. This loss can be overcome by fortification. This has a better nutritive value, not due to an increase in nutrients but an increase in digestibility.