Influence of Surfactants on Lipase Fat Digestion in a Model Gastro-intestinal System.
In the present study, we use a model gastro-intestinal system to study the influence of different food-grade surface-active molecules (Sn-2 monopalmitin, beta-lactoglobulin, or lysophosphatodylcholine) on lipase activity. The interfacial activity of lipase and surfactants are assessed with the pendant drop technique, a commonly used tensiometry instrument. A mathematical model is adopted which enables quantitative determination of the composition of the water-oil interface as a function of bulk surfactant concentration in the water-oil mixtures. Our results show a decrease in gastric lipolysis when interfacially active molecules are incorporated into a food matrix. However, only the Sn-2 monopalmitin caused a systematic decrease in triglyceride hydrolysis throughout the gastro-intestinal tract. This effect is most likely due to exclusion of both lipase and triglyceride from the water-oil interface together with a probable saturation of the solubilization capacity of bile with monoglycerides. Addition of beta-lactoglobulin or lysophopholipids increased the hydrolysis of fat after the gastric phase. These results can be attributed to an increasing interfacial area with lipase and substrate present at the interface. Otherwise, beta-lactoglobulin, or lysophopholipids reduced fat hydrolysis in the stomach. From the mathematical modeling of the interface composition, we can conclude that Sn-2 monopalmitin can desorb lipase from the interface, which, together with exclusion of substrate from the interface, explains the gradually decreased triglyceride hydrolysis that occurs during the digestion. Our results provide a biophysics approach on lipolysis that can bring new insights into the problem of fat uptake.
Reis
Pedro M
PM
Raab
Thomas W
TW
Chuat
Jean Y
JY
Leser
Martin E
ME
Miller
Reinhard
R
Watzke
Heribert J
HJ
Holmberg
Krister
K
J Physiol. 1944 Dec 15;103(3):306-16
16991648
Nature. 2007 Jun 21;447(7147):959-65
17554340
J Lipid Res. 1983 Oct;24(10):1336-42
6644184
Adv Colloid Interface Sci. 2003 Dec 1;106:237-59
14672849
J Colloid Interface Sci. 2000 Dec 1;232(1):25-32
11071728
Annu Rev Physiol. 1983;45:651-77
6342528
Eur Heart J. 1985 Feb;6(2):158-67
4006968
Langmuir. 2008 Jul 15;24(14):7400-7
18547084
J Biol Chem. 1979 Dec 10;254(23):12121-5
40991
J Biol Chem. 2002 Aug 2;277(31):28070-9
11940604
Langmuir. 2008 Jun 3;24(11):5781-6
18454561
J Am Oil Chem Soc. 1966 May;43(5):286-9
5933463
Biochimie. 1976;58(6):751-3
953065
Gastroenterology. 1982 Dec;83(6):1306-12
7129034
Best Pract Res Clin Gastroenterol. 2004 Dec;18(6):1049-72
15561638
Anal Biochem. 2001 Jul 1;294(1):36-43
11412003
Langmuir. 2008 Jun 1;24(13):6812-9
18512870
Biosci Biotechnol Biochem. 2005 May;69(5):932-8
15914912
J Lipid Res. 1998 Mar;39(3):623-32
9548594
Eur J Clin Nutr. 1996 Mar;50(3):125-33
8654325
Biochim Biophys Acta. 2004 Aug 30;1684(1-3):1-7
15450204
J Colloid Interface Sci. 2004 Jun 15;274(2):496-501
15144822