Slow digestion properties of long-sized isomaltooligosaccharides synthesized by a transglucosidase from Thermoanaerobacter thermocopriae

Abstract

Isomaltooligosaccharides (IMOs) are widely used as prebiotic ingredients that promote colon health; however, recent studies revealed that these are slowly hydrolyzed to glucose within the small intestine. Here, novel alpha-glucans with a higher number of alpha-1,6 linkages were synthesized from maltodextrins using the Thermoanaerobacter thermocopriae-derived transglucosidase (TtTG) to decrease susceptibility to hydrolysis and improve slow digestion properties. The synthesized long-sized IMOs (L-IMOs; 70.1% of alpha-1,6 linkages), comprising 10-12 glucosyl units, exhibited slow hydrolysis to glucose when compared to commercial IMOs under treatment with mammalian alpha-glucosidase level. In male mice, the ingestion of L-IMOs significantly decreased the post-prandial glycemic response compared to other samples (p < 0.05). Therefore, enzymatically synthesized L-IMOs can be applied as functional ingredients for the modulation of blood glucose homeostasis in obesity, Type 2 diabetes, and other chronic diseases.