PRODUCTION AND SOME PROPERTIES OF A DEXTRIN WITH A NARROW SIZE DISTRIBUTION BY THE CYCLIZATION REACTION OF BRANCHING ENZYME

Branching enzyme (BE, EC 2.4.1.18) catalyzes the cyclization of amylos e and amylopectin (Takata et al., J. Bacteriol., 178, 1600-1606, 1996; Takata et al., Carbohydr. Res., 295, 91-101, 1996). Amylopectin was c onverted to dextrin using the cyclization reaction of BE from Bacillus stearothermophilus TRBE14. The enzyme efficiently degraded amylopecti n even when the concentration of substrate was high (20-30% w/w), and the product had a narrow molecular weight distribution compared with t hose of commercial dextrins. These results suggest that BE may be usef ul as a new starch-processing enzyme. The product was highly soluble i n water to give a highly stable, clear solution. The results also sugg est that the product reduces the tendency of other dextrins to undergo retrogradation.