Structural changes of bovine milk fat globules during in vitro digestion.
An in vitro digestion model that simulated gastric and intestinal fasting conditions was used to monitor the physical, chemical, and structural changes of fat globules from raw bovine milk. During in vitro gastric digestion, the fat globules were stable under low-acidic conditions. Some peptides and β-lactoglobulin were resistant to proteolysis by pepsin. Phospholipids, proteins, and peptides stabilized the globules in the stomach model. During in vitro intestinal digestion, most of the β-lactoglobulin and residual peptides were hydrolyzed by trypsin and chymotrypsin, and the lipolytic products, released from the hydrolysis of the triglyceride core of the globules, led to destabilization and coalescence of the globules. By accumulating at the surface of the fat globules, the lipolytic products formed a lamellar phase and their solubilization by bile salts resulted in the formation of disk-shaped micelles. This study brings new interesting insights on the digestion of bovine milk.
Riddet Institute, Massey University, Private Bag 11 222, Palmerston North 4442, New Zealand. S.Gallier@massey.ac.nz
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D000818:Animals; D002417:Cattle; D002918:Chymotrypsin / Q000378:metabolism; D004063:Digestion; D006017:Glycolipids / Q000378:metabolism*; D006023:Glycoproteins / Q000378:metabolism* / Q000648:ultrastructure; D066298:In Vitro Techniques; D007782:Lactoglobulins / Q000378:metabolism; D066292:Lipid Droplets; D008066:Lipolysis; D008823:Micelles; D018613:Microscopy, Confocal; D008894:Milk Proteins / Q000378:metabolism; D059748:Proteolysis; D014357:Trypsin / Q000378:metabolism
D006017:Glycolipids; D006023:Glycoproteins; D007782:Lactoglobulins; D008823:Micelles; D008894:Milk Proteins; C110367:milk fat globule; D002918:Chymotrypsin; D014357:Trypsin