Evaluation of Prebiotic Effects of High-Purity Galactooligosaccharides in vitro and in vivo

Galactooligosaccharides (GOS) are an important class of dietary prebiotics that exert beneficial effects on intestinal microbiota and gut barrier function. In this study, high-purity GOS (HP-GOS) were investigated in vitro and in vivo and confirmed as prebiotic ingredients in rat diet. HP-GOS were successfully produced using a two-step process, enzymatic hydrolysis and fermentation by yeast. They were found to serve as a good substrate and carbon source for supporting the growth of probiotic bacteria more effectively than other commercial GOS. Following administration of 1 % (by mass) of HP-GOS to rats, the growth of Bifidobacterium bifidum and B. longum in the gut increased most rapidly up to 12 h, and thereafter the increase was slow. Therefore, 1 % HP-GOS was found to be acceptable for the growth of probiotic bacteria. Groups of animals that were orally administered HP-GOS and bifidobacteria during the study, and the group administered HP-GOS during the 2nd (days 13–15) and 4th (days 28–30) period of the study had significantly (p