Digestibilité des matières grasses chez l'homme

Abstract

Digestion of dietary fat, mainly composed of triglycerides (97%) but also of phospholi-pids (3%), is due to the successive action of different lipases of the human digestive tract. Lingual lipase acts only in the oral cavity and hydrolyses few triglycerides molecules leading to the release of fatty acids at the sn-3 position on the glycerol black-bone, which depending on their type (oleiC., linoleic or linolenic acid), will permit a more or less important orosensory detection of fat leading to preference for fatty foods and digestive anticipation process. Gastric lipase hydrolyses 25 to 40% ingested triglycerides in the stomach releasing fatty acids at the sn-3 position, and the short and medium chain fatty acids generated might be absorbed directly via the gastric mucosa. Pancreatic lipases finish the fat digestion leading to the formation of free fatty acids, 2-monoglycerides and lysophospholipids. The efficiency of the digestion might depend on different factors: fat supramolecular organization of dairy products (native fat globules, aggregates or coalesced globules, free desorganized fat), the globule size (small-sized globule are more efficiently digested), globule surface ultrastructure (species of phospholipids, presence of dairy proteins).