Physicochemical characteristics of emulsions during fat digestion
in the human stomach and duodenum.
Armand, Martine, Patrick Borel, Berengere Pasquier, Christophe Dubois,
Michele Senft, Marc Andre, Jacques Peyrot, Jacques Salducci, and
Denis Lairon.
Unit[acute]e 130-INSERM (National Institute of Health and Medical
Research), 18 avenue Mozart, 13009 Marseille, France, INRA,
Unit[acute]e des Maladies M[acute]etaboliques, CRNH, BP 321, 58 rue
Montalembert, 63009 Clermont-Ferrand cedex 1, France, Service
d'Hepato-Gastro-Enterologie, Centre Hospitalier Universitaire Nord,
13015 Marseille, France
APStracts 2:0231G, 1995.
Seven fasting subjects were fitted with nasogastric and nasoduodenal
tubes and received intragastrically a coarsely emulsified test meal.
Gastric and duodenal aspirates were collected after 1, 2, 3 and 4 h.
In the duodenum, most lipids (>90%) were present as emulsified
droplets sizing 1-100 [mu]m. Large droplets and unemulsified material
present in the test meal (> 100 [mu]m) disappeared while smaller
droplets (1-50 [mu]m) were generated after 1h digestion. Thus, the
median lipid droplet diameter significantly decreased (19.6 vs 56.5
[mu]m in the test meal) and the droplet surface area significantly
increased (1.58 vs 0.70 m2/g fat). Intermediate figures for droplet
diameter were obtained, i.e. 34.3, 46.3, 27.6 [mu]m after 2, 3 and 4
h, respectively. In the stomach, a comparable emulsion particle-size
pattern was observed with droplet median diameters such as 17.2,
37.9, 52.4 and 41.6 [mu]m after 1, 2, 3, and 4 h. Nevertheless, the
extent of triglyceride hydrolysis was much lower in the stomach (6
-16%) than in the duodenum (42-45%) where small droplets were enriched
in lipolytic products, cholesterol and phospholipids. The present
findings show for the first time that most dietary lipids are present
in the human duodenum as emulsified droplets of size 1-50 [mu]m and
that no further marked emulsification of dietary fat occurs in the
duodenum compared to the stomach.
Received 30 May 1995; accepted in final form 4 November 1995.
APS Manuscript Number G229-5.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 30 November 95