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In vitro Digestion of Emulsions in a Single Droplet via Multi Subphase Exchange of Simulated Gastrointestinal Fluids
Published on: November 18, 2022
Competition between lipases and monoglycerides at interfaces
Pedro Reis1, Krister Holmberg, Reinhard Miller
1Nestle Research Center, CH-1000 Lausanne 26, Switzerland.
Langmuir : the ACS Journal of Surfaces and Colloids
|June 13, 2008
Summary
Polar lipids from fat digestion, specifically Sn-2 monoglycerides, actively expel lipases from oil-water interfaces. This self-regulatory process impacts in vivo fat digestion by gastrointestinal lipases.
Area of Science:
- Biochemistry
- Physical Chemistry
- Digestive Physiology
Background:
- Lipases play a crucial role in dietary fat digestion by hydrolyzing triglycerides.
- The behavior of lipases at the oil-water interface is influenced by digestion products, such as polar lipids.
- Understanding lipase-interface interactions is key to comprehending fat digestion efficiency.
Purpose of the Study:
- To investigate the impact of polar lipids, generated during fat digestion, on lipase behavior at the oil-water interface.
- To differentiate the effects of Sn-1,3 regiospecific and nonregiospecific lipases on interfacial phenomena.
- To elucidate the self-regulatory mechanisms in fat digestion.
Main Methods:
- Tensiometry using the pendant drop technique to measure interfacial tension.
- Interfacial shear rheology to assess the mechanical properties of the interface.
- Ellipsometry to study interfacial layer formation and structure.
Main Results:
- Sn-2 monoglycerides, produced by Sn-1,3 regiospecific lipases, are highly interfacially active and displace lipases from the interface.
- Lipases form a sublayer in the aqueous phase beneath the monoglyceride-covered interface.
- Sn-1/3 monoglycerides are rapidly degraded, and resulting fatty acids do not effectively expel lipases.
- Noncatalytically active beta-lactoglobulin served as a control in rheology experiments.
Conclusions:
- The formation of stable, amphiphilic Sn-2 monoglycerides acts as a self-regulatory mechanism controlling fat digestion.
- Results are transferable to in vivo conditions due to the high Sn-1,3 regiospecificity of gastrointestinal lipases.
- Interfacial activity of digestion products significantly modulates lipase function and fat digestion kinetics.
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