Ex vivo digestion of raw, pasteurised and homogenised milk - Effects on lipolysis and proteolysis

This study investigated the impact of pasteurisation and homogenisation on ex vivo gastrointestinal digestion of proteins and fat in bovine milk. Milk that was homogenised at 150 bar showed the highest degree of lipolysis (78%) after 120 min duodenal digestion. In comparison, milk homogenised at 50 bar showed 56% release of fatty acids whereas raw and pasteurised milk showed 49% and 44% hydrolysis, respectively. Pasteurisation had very much less effect upon lipolysis and proteolysis. Homogenisation increased the gastric proteolysis of specifically β-lactoglobulin, and also of α-lactalbumin. However, after 5 min duodenal digestion all the proteins were degraded in all milks tested. Thus, both lipolysis and proteolysis were increased by homogenisation of the milk, making fatty acids from lipids and peptides from β-lactoglobulin more readily available to the human body.