Effect of heat treatment on micronutrients, fatty acids and some bioactive components of milk

Milk is a nutrient-rich food with various micronutrients and bioactive components that are affected by heat treatment depending on time-temperature norm. Pasteurisation and short time ultra high temperature treatments do not cause significant changes in most micronutrients; however, intensive heat treatments such as in-bottle sterilisation can cause severe degradation of water-soluble vitamins, essential fatty acids and hormones. Exposure of heat-treated milk to light and oxygen has a more destructive effect on oxygen-sensitive micronutrients, unsaturated fatty acids and most vitamins than heat treatment itself. Therefore, losses during evaporation and drying processes can be significant and should be considered in evaluating the nutritional value of milk. Moreover, packaging material, storage temperature and duration also contribute to the losses. Application of severe heat may also cause minor losses in minerals due to precipitation in processing lines. An integral approach is recommended for retention of the nutritional value of raw milk in processed milk products.