BRANCHED FATTY-ACID TYPE AND ITS EFFECT O N TRIGLYCERIDE HYDROLYSIS BY PANCREATIC LIPASE AND INTESTINAL-ABSORPTION

In vitro, hydrolysis maximal rates (R(max)) by pancreatic lipase of tr i-isopalmitoyl glycerol and an oil without branched-chain fatty acids (BCFA), such as soybean oil, are the same (26 micromoles of released f atty acid/min/mg enzymatic proteins). With tri-(methyl-2-tridecanoyl) glycerol, the R(max) is four limes lower As a result, when tri-isopalm itoyl glycerol is given to rats cannulated thoracic duct, iso-palmitic acid is quantitatively recovered in the 24 h collected lymph. Compara tively to the corresponding iso-BCFA, the 24 h lymphatic recovery of a 2-methyl (or 3-methyl) BCFA is only 3% or 53%, according as these two BCFA are located either at the sn-1 and sn-3 positions, or at the sn- 2 position, of the triacyl glycerol fed to the rats. The distribution of iso- and anteiso-BCFA between the three sn-positions of tallow trig lycerides was determined. Except 17:0 iso, all the other BCFA were in majority, or exclusively located al the sn-2 position. This peculiar l ocalisation favours intestinal absorption, as the micellar solubility of a 2-monoglyceride is greater than that of the corresponding free fa tty acid.