Small intestinal brush border membrane vesicles (BBMV) from pig were used to evaluate the digestibility of different mixtures of galactooligosaccharides from lactose (GOS), differing in the predominant glycosidic linkage, and from lactulose (OsLu). Dissimilar hydrolysis rates were detected after BBMV digestion. Predominant glycosidic linkages and monomeric composition showed to play a key role in the resistance to intestinal mammalian digestive enzymes. β(1→3) GOS mixture was the most susceptible to hydrolysis with 50.2 % of degradation after digestion, followed by β(1→4) with 34.9 % hydrolysis, whereas β(1→6) linkages showed to be highly resistant to digestion (27.1 %). Monomeric composition seems to provide a better resistance in β(1→6) oligosaccharides from lactulose (22.8 %) as compared to β(1→6)-GOS (27.1 %). This was also observed in β-galactosyl-fructoses and β-galactosyl-glucoses disaccharides where the presence of fructose provided a higher resistance to digestion. Thus, the resistance to small intestinal digestive enzymes highly depends on structural characteristic and composition of prebiotic ingredients. Increasing knowledge on this regard could contribute to the future synthesis of new tailored prebiotic with specific functional properties.

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