681 INHIBITION OF MALTOPENTAOSE (MP) ABSORPTION BY MEDIUM AND LONG CHAIN ELEMENTS IN CORN STARCH HYDROLYSATE (CSH)

To define optimal carbohydrates for infants with limited pancreatic and intestinal mucosal function we synthesized and evaluated the absorption of ¹⁴C-MP - a glucose oligomer ideally suited to glucoamylase activity. Representative medium (degree of polymerization, DP, 4-9) and long chain (DP±75) polymers were isolated from a CSH. Using partially atrophic, pancreatic amylase-free, canine, jejunal, Thiry-Vella fistulae, absorption of DP 5 was measured: alone, in the presence of 90, 180, 270, 360 and 450 mg/dl of DP 4-8, with similar concentrations of DP±75 and with 450 mg/dl of sucrose.

Results: Absorption of DP 4-8 was greater than sucrose which exceeds DP±75. Although at 450 mg/dl there was equivalent inhibition of DP 5 absorption by DP 4-8 (46%) and DP±75 (45%), at 90 mg/dl, inhibition by DP 4-8 was significantly less than by DP 75 (10 vs. 27%, p<.01). Sucrose did not inhibit DP 5 absorption (p<.001).

Conclusions: 1)Although assimilation of glucose polymers is less efficient than shorter oligomers, both inhibit DP 5 absorption. 2)At low concentrations the greater inhibition by DP±75 probably reflects a protracted affinity for the glucoamylase enzyme. 3)Sucrose does not compete for oligomer assimilation.

Speculation: These results suggest that substitution of sucrose for a portion of the polymers in a CSH, especially the long chain elements, will improve carbohydrate absorption.